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Sample records for brazilian semi-arid region

  1. TANNIN POTENCIAL EVALUATION OF SIX FOREST SPECIES OF BRAZILIAN SEMI-ARID REGION

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    Juarez Benigno Paes

    2006-09-01

    Full Text Available The hide tanners of Brazil Northeast region have in Anadenanthera colubrina (Vell. Brenan var. cebil (Gris. Alts. their only source of tannins. As the activity of exploration is extractiviste without the concern of recovery of explored trees and the absence of other tannin sources, exposes the specie to exhaustion and the tanners and extractivistes family to go bankruptcy. Thus, this work aimed to evaluate the tanin potential of Prosopis juliflora, Anadenanthera colubrina var. cebil, Anacardium occidentale, Mimosa tenuiflora, Mimosa arenosa and Croton sonderianus. These species, Anacardium occidentale, Mimosa arenosa and Mimosa temuiflora showed, respectively, 19.83%, 18.11% and 17.74% of tannins. The Anadenanthera colubrina showed 11.89% and was inferior them mentioned species. The Prosopis juliflora and Croton sonderianus showed 3.02% and 6.62%, respectively. The abundance of Mimosa arenosa and Mimosa tenuiflora in the Brazilian Semi-arid proposes them as potential of tannin production. However, there is need of researches to verify their technical viability for skins, as well as for other uses for tannins.

  2. Conceptual model for water management in Brazilian semi-arid regions: From intervention to sustainability, case of Lagoa Real Uranium Plant

    International Nuclear Information System (INIS)

    The world water lack problem has been already diagnosed and is acknowledged as one of the greatest challenges for this century. The scientific literature, documents and either nationals or internationals official reports like the Brazilian Water Agency (ANA) and UNESCO point out the main shortages and general management practices. Also in Brazil, it is a multi-facet problem that envelops several social agents for many decades and has tragic consequences in some regions of the country, like is the case of the northeastern semi-arid region. This work presents the strategies for expertise integration to attend demands for the establishment of partnerships that include several institutions, with different experiences in the region, to improve the acquaintance with dry climate in Brazilian semi-arid. The general objective was developing a conceptual model of technical multi-institutional arrangements as tools for aquifer management, promoting sustainable use of groundwater in the semi-arid region. Here, we present a conceptual model based in technical, political and socio-economical dimensions of sustainability that exchange information among them and with management requirements. This process must be turned in more productive agricultural systems with the introduction of new technology that respect the family arrangement of the production units. It is also expected that validation of this conceptual model allows an applicable alternative to other areas in the future, respected of course all the geo-socio-economical constraints of each site. (author)

  3. Conceptual model for water management in Brazilian semi-arid regions: From intervention to sustainability, I. Case of Lagoa Real uranium plant

    International Nuclear Information System (INIS)

    The world water lack problem has been already diagnosed and is acknowledged as one of the greatest challenges for this century. The scientific literature, documents and either nationals or internationals official reports like the Brazilian Water Agency (ANA) and UNESCO point out the main shortages and general management practices. Also in Brazil, it is a multi-facet problem that envelops several social agents for many decades and has tragic consequences in some regions of the country, like is the case of the northeastern semi-arid region. This work presents the strategies for expertise integration to attend demands for the establishment of partnerships that include several institutions, with different experiences in the region, to improve the acquaintance with dry climate in Brazilian semi-arid. The general objective was developing a conceptual model of technical multi-institutional arrangements as tools for aquifer management, promoting sustainable use of groundwater in the semi-arid region. A conceptual model is shown, based on technical, political and socio-economical dimensions of sustainability that exchange information among them and with management requirements. This process must be turned in more productive agricultural systems with the introduction of new technology that respect the family arrangement of the production units. It is also expected that validation of this conceptual model allows an applicable alternative to other areas in the future, respected of course all the geo-socio-economical constraints of each site. The newest uranium plant being operated in Brazil is located at a semi-arid region, in the municipalities of Lagoa Real and Caetite, State of Bahia, northeast region of Brazil, which shows rainfall rates of 800 mm/a. Its known resources were estimated as being of 85,000 tU at below $80/kgU cost category. The ore is mined by open pit methods and uranium is extracted by acid heap leaching. The conceptual operation plan did not include liquid

  4. Spatial and temporal distribution of free-living protozoa in aquatic environments of a Brazilian semi-arid region

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    Maria Luisa Quinino de Medeiros

    2013-08-01

    Full Text Available Free-living protozoa organisms are distributed in aquatic environments and vary widely in both qualitative and quantitative terms. The unique ecological functions they exhibit in their habitats help to maintain the dynamic balance of these environments. Despite their wide range and abundance, studies on geographical distribution and ecology, when compared to other groups, are still scarce. This study aimed to identify and record the occurrence of free-living protozoa at three points in Piancó-Piranhas-Açu basin, in a semi-arid area of Rio Grande do Norte (RN state, and to relate the occurrence of taxa with variations in chlorophyll a, pH and temperature in the environments. Samples were collected in the Armando Ribeiro Gonçalves Dam, from two lentic environments upstream and a lotic ecosystem downstream. Sixty-five taxa of free-living protozoa were found. The Student's t-test showed significant inter-variable differences (p <0.05. Similar protozoan species were recorded under different degrees of trophic status according to chlorophyll a concentrations, suggesting the organisms identified are not ideal for indicating trophic level. We hypothesize that food availability, the influence of lentic and lotic systems and the presence of aquatic macrophytes influenced protozoan dynamics during the study period.

  5. Waste biorefinery in arid/semi-arid regions.

    Science.gov (United States)

    Bastidas-Oyanedel, Juan-Rodrigo; Fang, Chuanji; Almardeai, Saleha; Javid, Usama; Yousuf, Ahasa; Schmidt, Jens Ejbye

    2016-09-01

    The utilization of waste biorefineries in arid/semi-arid regions is advisable due to the reduced sustainable resources in arid/semi-arid regions, e.g. fresh water and biomass. This review focuses on biomass residues available in arid/semi-arid regions, palm trees residues, seawater biomass based residues (coastal arid/semi-arid regions), and the organic fraction of municipal solid waste. The present review aims to describe and discuss the availability of these waste biomasses, their conversion to value chemicals by waste biorefinery processes. For the case of seawater biomass based residues it was reviewed and advise the use of seawater in the biorefinery processes, in order to decrease the use of fresh water. PMID:27072789

  6. Salinization mechanisms in semi-arid regions

    International Nuclear Information System (INIS)

    During a period of three years the basins of the Pereira de Miranda and Caxitore dams, located in the crystalline rock area of Ceara, Brazil, were studied in order to determine the mechanisms of salinization of their waters. Isotope methods (18O/16O) and hidrochemistry (determination of the of the maior ions) were applied to surface, underground and rain water in this study. An isotope model was designed and applied to the determination of evaporation and percolation of dams in semi-arid zones during the dry season. The results are compared to those from a conventional chemical model. As causes of salinization of the water in the dams, the contributions of the rain itself and the lixiviation of the soil are quantified. An interaction between the dams and the underground water is imperceptible. The salinization of the underground water is attributed to recharge of the aquifer with rain water from the surface runoff followed by evaporation of the water rising, due to capilarity, in a one-directional flow to the surface. (Author)

  7. Arbuscular mycorrhizal fungi in Mimosa tenuiflora (Willd.) Poir from Brazilian semi-arid.

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    de Souza, Tancredo Augusto Feitosa; Rodriguez-Echeverría, Susana; de Andrade, Leonaldo Alves; Freitas, Helena

    2016-01-01

    Many plant species from Brazilian semi-arid present arbuscular mycorrhizal fungi (AMF) in their rhizosphere. These microorganisms play a key role in the establishment, growth, survival of plants and protection against drought, pathogenic fungi and nematodes. This study presents a quantitative analysis of the AMF species associated with Mimosa tenuiflora, an important native plant of the Caatinga flora. AMF diversity, spore abundance and root colonization were estimated in seven sampling locations in the Ceará and Paraíba States, during September of 2012. There were significant differences in soil properties, spore abundance, percentage of root colonization, and AMF diversity among sites. Altogether, 18 AMF species were identified, and spores of the genera Acaulospora, Claroideoglomus, Dentiscutata, Entrophospora, Funneliformis, Gigaspora, Glomus, Racocetra, Rhizoglomus and Scutellospora were observed. AMF species diversity and their spore abundance found in M. tenuiflora rhizosphere shown that this native plant species is an important host plant to AMF communities from Brazilian semi-arid region. We concluded that: (a) during the dry period and in semi-arid conditions, there is a high spore production in M. tenuiflora root zone; and (b) soil properties, as soil pH and available phosphorous, affect AMF species diversity, thus constituting key factors for the similarity/dissimilarity of AMF communities in the M. tenuiflora root zone among sites. PMID:26991277

  8. Uses of tree legumes in semi-arid regions

    Energy Technology Data Exchange (ETDEWEB)

    Felker, P.

    1980-01-01

    Uses of tree legumes in semi-arid and arid regions are reviewed. This review is divided into sections according to the following general use categories: fuels; human food; livestock food; to increase yields of crops grown beneath their canopies;and control of desertification. (MHR)

  9. Geochemistry and isotope evolution of groundwater flow and recharge from the uranium production center in Brazilian semi-arid region (Caetite-BA, Brazil) - Towards sustainability or shortage?

    International Nuclear Information System (INIS)

    The semi-arid region of the Northeast of Brazil is characterized by a lack of superficial waters due to the low pluviometric precipitation and high evaporation rates. Owing to these adverse climatic conditions, intense pressure is being put on the use of groundwater resources. However, there is still insufficient knowledge of the basic aquifers characteristics leading to an over exploitation of the water resources. The prevailance of crystalline rocks is connected to a fracture aquifer type of low productivity, where wells show, generally, yield rates lower than 3 m3·h-1. This work was developed in a semi-arid area located in the center-south region of Bahia State at 900 metres a.s.l., where were discovered several radioactive anomalies by aerogeophysical surveys performed during 70's decade, that allowed to set the uranium province named Lagoa Real. There were performed isotopic and geochemical analysis of groundwater sampled from twenty-five wells placed in crystalline rocks areas (granite or gneiss) covered by short layers of residual soil or alluvial sediments. The samples were analysed in a mass spectrometer for stable isotopic ratios, like δ2H, δ18O, δ13C (per mille VSMOW) and also measured for radiocarbon activity concentration (14C) to calculate the percentage of modern carbon (PMC) by AMS. The values of δ2H and δ18O defined a local evaporation line (LEL) with slope equal to 4.6 against the value of 7.4 for the Local Meteoric Water Line (Salvador station from 1972 to 1976). The radiocarbon ages, corrected by carbonate dissolution (through δ13C and DIC), showed very young waters that were recently recharged, perhaps during the last few years to several months. The supposed old ages for the fractured aquifer are not accomplished by radiocarbon dating, showing it is unconfined with no discharge of old groundwater through deep faults and short residence time. Thus, the groundwater offer for multiple uses (in terms of quantity) seems to be assured if the

  10. Helminthological records of six-banded armadillos Euphractus sexcinctus (Linnaeus, 1758) from the Brazilian semi-arid region, Patos county, Paraíba state, including new morphological data on Trichohelix tuberculata (Parona and Stossich, 1901) Ortlepp, 1922 and proposal of Hadrostrongylus ransomi nov. comb.

    Science.gov (United States)

    Hoppe, E G L; Araújo de Lima, R C; Tebaldi, J H; Athayde, A C R; Nascimento, A A

    2009-05-01

    This work aimed to evaluate the gastrointestinal helminthfauna composition of six-banded armadillos from the Brazilian semi-arid region. Gastrointestinal contents of six road-killed adult animals from Patos County, Paraíba State, were analyzed. Six species of nematodes, comprising five genera and four families, were recovered from the analyzed animals. New morphological data on Trichohelix tuberculata is given, along with a new taxonomical proposal for Hadrostrongylus ransomi (Travassos, 1935) n. comb. This is the first record for parasitic helminths in this host from the Brazilian semi-arid.

  11. Expansive Soil Properties in a Semi-Arid Region

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    MuawiaA. Dafalla

    2012-11-01

    Full Text Available The expansive soils in semi-arid regions are of great concern to design and geotechnical engineers. Range and variations of geotechnical properties of soils are very useful for appropriate design. Saudi Arabia; a semi arid region attracted the attention of researchers and practicing engineers over the last three decades following the rapid urbanizations in different parts of the country. Advanced testing equipments were made available for this study. The research group conducted joint visits with high officials from different municipality authorities to survey the problem and study the extent of damage to various structures. The areas visited included Al Ghatt, Al Zulfi, Al Hofuf, Um Al Sahik, Al Qatif, Tabuk, Tayma and Al Qaleeba. Single and two storey buildings, boundary walls, pavements and asphalt roads suffered significant damage in many parts of the visited locations. This paper presents the outcome of survey and a general review of previous works carried out for swelling clays in Saudi Arabia. Engineering properties for typical soil formation are presented.

  12. Annual plants in arid and semi-arid desert regions

    Institute of Scientific and Technical Information of China (English)

    Xuehua LI; Xiaolan LI; Deming JIANG; Zhimin LIU; Qinghe YU

    2008-01-01

    Annual plants are the main vegetation in arid and semi-arid desert regions.Because of their unique traits,they are the optimal experimental subjects for eco-logical studies.In this article,we summarize annual plants' seed germination strategies,seedling adaptability mechanism to environments,seed dispersal,and soil seed banks.We also discuss the biotic and abiotic factors affecting the composition and dynamics of annual plant populations and communities.Because annual plants have important ecological functions in desert vegetation systems,this study on annual plants will be of great bene-fit to the conservation and restoration of desert ecosys-tems,the rational utilization of resources,and the sustainable development of desert regions.

  13. Karst characterization in a semi-arid region using gravity, seismic, and resistivity geophysical techniques.

    Energy Technology Data Exchange (ETDEWEB)

    Barnhart, Kevin Scott

    2013-10-01

    We proposed to customize emerging in situ geophysical monitoring technology to generate time-series data during sporadic rain events in a semi-arid region. Electrodes were to be connected to wireless \

  14. Outcrop Groundwater Prospecting, Drilling, and Well Construction in Hard Rocks in Semi-arid Regions

    OpenAIRE

    Chambel, António

    2014-01-01

    This chapter presents some recommendations for prospecting, drilling and well construction in hard rocks in semi-arid regions. Considering that these conditions are present in many countries where technology is not always available, the chapter concentrates on the most basic and simple methods to plan where best to drill and maximize success through the direct observation of rock types, weathering and fracturing. The advantage for the geologist and hydrogeologist in an arid or semi-arid envir...

  15. The relationship between anthropogenic dust and population over global semi-arid regions

    Science.gov (United States)

    Guan, Xiaodan; Huang, Jianping; Zhang, Yanting; Xie, Yongkun; Liu, Jingjing

    2016-04-01

    Although anthropogenic dust has received more attention from the climate research community, its dominant role in the production process is still not identified. In this study, we analysed the relationship between anthropogenic dust and population density/change over global semi-arid regions and found that semi-arid regions are major source regions in producing anthropogenic dust. The results showed that the relationship between anthropogenic dust and population is more obvious in cropland than in other land cover types (crop mosaics, grassland, and urbanized regions) and that the production of anthropogenic dust increases as the population density grows to more than 90 persons km-2. Four selected semi-arid regions, namely East China, India, North America, and North Africa, were used to explore the relationship between anthropogenic dust production and regional population. The most significant relationship between anthropogenic dust and population occurred in an Indian semi-arid region that had a greater portion of cropland, and the high peak of anthropogenic dust probability appeared with 220 persons km-2 of population density and 60 persons km-2 of population change. These results suggest that the influence of population on production of anthropogenic dust in semi-arid regions is obvious in cropland regions. However, the impact does not always have a positive contribution to the production of anthropogenic dust, and overly excessive population will suppress the increase of anthropogenic dust. Moreover, radiative and climate effects of increasing anthropogenic dust need more investigation.

  16. Tropical Warm Semi-Arid Regions Expanding Over Temperate Latitudes In The Projected 21st Century

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    Rajaud, A.; de Noblet, N. I.

    2015-12-01

    Two billion people today live in drylands, where extreme climatic conditions prevail, and natural resources are limited. Drylands are expected to expand under several scenarios of climatic change. However, relevant adaptation strategies need to account for the aridity level: it conditions the equilibrium tree-cover density, ranging from deserts (hyper-arid) to dense savannas (sub-humid). Here we focus on the evolution of climatically defined warm semi-arid areas, where low-tree density covers can be maintained. We study the global repartition of these regions in the future and the bioclimatic shifts involved. We adopted a bioclimatological approach based on the Köppen climate classification. The warm semi-arid class is characterized by mean annual temperatures over 18°C and a rainfall-limitation criterion. A multi-model ensemble of CMIP5 projections for three representative concentration pathways was selected to analyze future conditions. The classification was first applied to the start, middle and end of the 20th and 21st centuries, in order to localize past and future warm semi-arid regions. Then, time-series for the classification were built to characterize trends and variability in the evolution of those regions. According to the CRU datasets, global expansion of the warm semi-arid area has already started (~+13%), following the global warming trend since the 1900s. This will continue according to all projections, most significantly so outside the tropical belt. Under the "business as usual" scenario, the global warm semi-arid area will increase by 30% and expand 12° poleward in the Northern Hemisphere, according to the multi-model mean. Drying drives the conversion from equatorial sub-humid conditions. Beyond 30° of latitude, cold semi-arid conditions become warm semi-arid through warming, and temperate conditions through combined warming and drying processes. Those various transitions may have drastic but also very distinct ecological and sociological

  17. Karst characterization in a semi-arid region using gravity, seismic, and resistivity geophysical techniques.

    Energy Technology Data Exchange (ETDEWEB)

    Barnhart, Kevin Scott

    2013-10-01

    We proposed to customize emerging in situ geophysical monitoring technology to generate time-series data during sporadic rain events in a semi-arid region. Electrodes were to be connected to wireless %5Cnodes%22 which can be left in the eld for many months. Embedded software would then increase sampling frequency during periods of rainfall. We hypothesized that this contrast between no-volume ow in karst passageways dur- ing dry periods and partial- or saturated-volume ow during a rain event is detectable by these Wireless Sensor Network (WSN) geophysical nodes, we call this a Wireless Resistivity Network (WRN). The development of new methodologies to characterize semi-arid karst hydrology is intended to augment Sandia National Laboratorys mission to lead e orts in energy technologies, waste disposal and climate security by helping to identify safe and secure regions and those that are at risk. Development and initial eld testing identi ed technological barriers to using WRNs for identifying semi-arid karst, exposing R&D which can be targeted in the future. Gravity, seismic, and resis- tivity surveys elucidated how each technique might e ectively be used to characterize semi-arid karst. This research brings to light the importance and challenges with char- acterizing semi-arid karst through a multi-method geophysical study. As there have been very few studies with this emphasis, this study has expanded the body of practical experience needed to protect the nations water and energy security interests.

  18. Estratégias para o desenvolvimento de novas cultivares de mangueira para o semiárido brasileiro Mango strategies to develop new varieties to the Brazilian tropical semi-arid region

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    Carlos Antonio Fernandes Santos

    2010-06-01

    Full Text Available A mangueira é uma das principais fruteiras comerciais no Semiárido brasileiro, sendo que a cultivar Tommy Atkins ocupa 85% da área total cultivada com a cultura. O objetivo deste trabalho foi avaliar o emprego de estratégias para reduzir o período juvenil e as trabalhosas polinizações manuais em mangueira, de forma a acelerar o desenvolvimento de novas cultivares da espécie para o Semiárido brasileiro. Foram identificadas plantas isoladas das cultivares Haden e Espada dentro de plantios comerciais da cultivar Tommy Atkins, numa fazenda exportadora de manga, em Petrolina-PE. Mudas das progênies foram transplantadas com seis meses de idade para o campo. O manejo para a indução floral foi realizado com poda, controle da irrigação e aplicação de Paclobutrazol e nitrato de potássio. O DNA extraído das progênies e parentais foi submetido a análises com marcadores microssatélites publicados para Mangifera indica L. O manejo combinado foi eficiente para induzir a floração e a frutificação em, aproximadamente, 70% das progênies após dois anos e meio de transplantio. Dos 94 indivíduos analisados com três microssatélites, 83% foram identificados como híbridos entre 'Haden' x 'T. Atkins'. Dos 401 indivíduos analisados com um microssatélite, 10% foram identificados como híbridos entre 'Espada' x 'T. Atkins'. A estratégia adotada foi eficiente para reduzir o período juvenil e evitar os trabalhosos cruzamentos manuais em mangueira, sendo que o desenvolvimento de novas cultivares da espécie para a região pode ser concluído com oito a dez anos, incluindo as rigorosas avaliações agronômicas.Mango is one of the most important fruit crop in the Brazilian Semi-Arid region. The cultivar Tommy Atkins has been grown in 85% of total area dedicated to this crop. The goal of this research was to evaluate strategies to reduce the juvenile period and to replace the laborious hand pollinization in order to accelerate the development

  19. Dynamic of epigeous macrofauna under organic soil management in the Brazilian semi-arid regionDinâmica da macrofauna epígea sob manejo orgânico do solo no semi-árido brasileiro

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    Márcio Sampaio Pimentel

    2012-04-01

    Full Text Available Soil macrofauna is responsible for soil fertility through cycling of nutrients, tillage and fragmentation of organic matter, as well as through the association between groups of fauna with conserved and/or degraded pedoenvironments. Nevertheless, under the conditions of the Brazilian semi-arid region, there is little information about this resource. The objective of this study was to evaluate the epigeous macrofauna in successive cropping using previous green manure and subsequent planting of melon (Cucumis melo L. in Juazeiro county, Bahia, Brazil. Sampling dates were undertaken in November 2007 and February, April and July 2008, using traps containing 4 % formaldehyde for seven days in plots of 64 m2. Results obtained indicate that there is no difference among the treatments with mixed cover crops, and epigeous macrofauna is influenced by the time of collection. Diversity and uniformity are inversely correlated with total density of epigeous macrofauna. Diversification of plant species favors the increase of diversity and uniformity of epigeous macrofauna. Formicidae, followed by Isopoda, Coleoptera and Oligochaeta are the groups of fauna most numerous in the areas. A macrofauna do solo é responsável pela melhoria da fertilidade do solo através da ciclagem de nutrientes, revolvimento e fragmentação da matéria orgânica, como também, pela associação entre grupos de fauna com pedoambientes conservados e/ou degradados. No entanto, nas condições de semi-árido brasileiro pouca informação se tem a respeito deste recurso. Neste sentido, na região do sub-médio do Rio São Francisco, pólo de desenvolvimento da agricultura irrigada objetivou-se avaliar a macrofauna epígea em sucessão cultural utilizando prévia adubação verde e subseqüente plantio de melão (Cucumis melo L.. As coletas foram realizadas em novembro de 2007 e fevereiro, abril e julho de 2008 no município de Juazeiro, BA, utilizando armadilhas contendo formol 4

  20. Semi-arid Northeast Brazil: integrated modelling of regional development and global change impacts

    NARCIS (Netherlands)

    Krol, Maarten S.; Fuhr, Dagmar; Döring, Andreas; Unruh, Jon D.; Krol, Maarten S.; Kliot, Nurit

    2004-01-01

    Societies in semi-arid areas in developing regions are amongst those most vulnerable to climate variability and potentially most vulnerable to climate change. The vulnerability to climate variability emerges from a combination of the level of availability of natural resources and the human dependenc

  1. A methodology to assess and evaluate rainwater harvesting techniques in (semi-) arid regions

    NARCIS (Netherlands)

    Adham, Ammar; Riksen, Michel; Ouessar, Mohamed; Ritsema, Coen J.

    2016-01-01

    Arid and semi-arid regions around the world face water scarcity problems due to lack of precipitation and unpredictable rainfall patterns. For thousands of years, rainwater harvesting (RWH) techniques have been applied to cope with water scarcity. Researchers have used many different methodologie

  2. Cyanobacterial occurrence and detection of microcystins and saxitoxins in reservoirs of the Brazilian semi-arid

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    Jessica Roberts Fonseca

    2015-03-01

    Full Text Available Aim:The rapid spread of cyanobacteria in water sources and reservoirs has caused serious environmental damage and public health problems, and consists in a problem that challenges the institutions responsible for providing water to the population. In this study, the quantification of microcystin, saxitoxins and cyanobacteria levels was performed over 3 years in the semi-arid reservoirs of Rio Grande do Norte (Brazil. In addition, we analyzed the seasonal distribution of cyanotoxins and the percentage of cyanobacteria and cyanotoxins which were above the limit established by Brazilian law.MethodsThe study was conducted between 2009 and 2011 in four dams with six sites: Armando Ribeiro Gonçalves (ARG in Itajá, San Rafael (SR and Jucurutu; Passagem das Traíras (PT; Itans and Gargalheiras (GARG. Cyanobacteria presence were quantified and identified and the presence of microcystins (MCYs and saxitoxins (STXs was investigated by ELISA.ResultsThe densities of cyanobacteria were found to be above the permitted in 76% of cases. The ELISA results showed that of the 128 samples analyzed, 27% were above the maximum allowed by the Brazilian Ministry of Health Order 2914/2011. A seasonal pattern for the presence of MCYs was found (0.00227 to 24.1954 µg.L–1, with the highest values in the rainy season. There was no clear seasonal pattern for STXs (0.003 to 0.766 µg.L–1.ConclusionsThis study showed the importance of establishing a water quality monitoring for human consumption and its potability standards since the concentration of MCYs in some samples was above the maximum limit allowed by Brazilian law, thus posing a risk to public health since the conventional water treatment is not able to eliminate these potent hepatotoxins.

  3. A Methodology to Assess and Evaluate Rainwater Harvesting Techniques in (Semi-) Arid Regions

    OpenAIRE

    Ammar Adham; Michel Riksen; Mohamed Ouessar; Coen J Ritsema

    2016-01-01

    Arid and semi-arid regions around the world face water scarcity problems due to lack of precipitation and unpredictable rainfall patterns. For thousands of years, rainwater harvesting (RWH) techniques have been applied to cope with water scarcity. Researchers have used many different methodologies for determining suitable sites and techniques for RWH. However, limited attention has been given to the evaluation of RWH structure performance. The aim of this research was to design a scientifical...

  4. Growing Vegetables Without Irrigation. More locally grown food in semi-arid regions is possible

    OpenAIRE

    Quinn, Robert M.

    2014-01-01

    There is a growing conflict between cities and agriculture for fresh water. To learn what we can grow without irrigation in semi-arid regions, and to demonstrate the potential of a more local food production, I have been experimenting with dry land storage vegetables (potatoes, winter squash and onions) on our organic farm in North Central Montana in the Northern Great Plains of North America.

  5. Effect of irrigation systems on temporal distribution of malaria vectors in semi-arid regions

    Science.gov (United States)

    Ohta, Shunji; Kaga, Takumi

    2014-04-01

    Previous research models have used climate data to explain habitat conditions of Anopheles mosquitoes transmitting malaria parasites. Although they can estimate mosquito populations with sufficient accuracy in many areas, observational data show that there is a tendency to underestimate the active growth and reproduction period of mosquitoes in semi-arid agricultural regions. In this study, a new, modified model that includes irrigation as a factor was developed to predict the active growing period of mosquitoes more precisely than the base model for ecophysiological and climatological distribution of mosquito generations (ECD-mg). Five sites with complete sets of observational data were selected in semi-arid regions of India for the comparison. The active growing period of mosquitoes determined from the modified ECD-mg model that incorporated the irrigation factor was in agreement with the observational data, whereas the active growing period was underestimated by the previous ECD-mg model that did not incorporate irrigation. This suggests that anthropogenic changes in the water supply due to extensive irrigation can encourage the growth of Anopheles mosquitoes through the alteration of the natural water balance in their habitat. In addition, it was found that the irrigation systems not only enable the active growth of mosquitoes in dry seasons but also play an important role in stabilizing the growth in rainy seasons. Consequently, the irrigation systems could lengthen the annual growing period of Anopheles mosquitoes and increase the maximum generation number of mosquitoes in semi-arid subtropical regions.

  6. Effect of irrigation systems on temporal distribution of malaria vectors in semi-arid regions.

    Science.gov (United States)

    Ohta, Shunji; Kaga, Takumi

    2014-04-01

    Previous research models have used climate data to explain habitat conditions of Anopheles mosquitoes transmitting malaria parasites. Although they can estimate mosquito populations with sufficient accuracy in many areas, observational data show that there is a tendency to underestimate the active growth and reproduction period of mosquitoes in semi-arid agricultural regions. In this study, a new, modified model that includes irrigation as a factor was developed to predict the active growing period of mosquitoes more precisely than the base model for ecophysiological and climatological distribution of mosquito generations (ECD-mg). Five sites with complete sets of observational data were selected in semi-arid regions of India for the comparison. The active growing period of mosquitoes determined from the modified ECD-mg model that incorporated the irrigation factor was in agreement with the observational data, whereas the active growing period was underestimated by the previous ECD-mg model that did not incorporate irrigation. This suggests that anthropogenic changes in the water supply due to extensive irrigation can encourage the growth of Anopheles mosquitoes through the alteration of the natural water balance in their habitat. In addition, it was found that the irrigation systems not only enable the active growth of mosquitoes in dry seasons but also play an important role in stabilizing the growth in rainy seasons. Consequently, the irrigation systems could lengthen the annual growing period of Anopheles mosquitoes and increase the maximum generation number of mosquitoes in semi-arid subtropical regions.

  7. Isotope and radiation techniques for efficient water and fertilizer use in semi-arid regions

    International Nuclear Information System (INIS)

    The Joint FAO/IAEA Division carried out a coordinated research programme, which was concerned with the efficiency of water and fertilizer uses in semi-arid farming systems. The present publication is a summary of the individual contributions from Belgium, Chile, Ivory Coast, Cyprus, France, India, Israel, Romania, Senegal, Sri Lanka and the United States of America, over the period 1978-1984. Water and fertilizer uptake by crops are dynamic processes affected by several factors of the soil-plant-atmosphere system. The neutron moisture meters were used not only to measure soil water contents but also to understand water dynamics under field conditions. Nitrogen is the most limiting nutrient in many semi-arid regions, and as its absorption is very much related to water dynamics in the soil, experiments using N-15 labelled fertilizer were carried out, which are presented in this report

  8. ARBUSCULAR MYCORRHIZAL FUNGI IN SUCCESSIONAL STAGES OF CAATINGA IN THE SEMI-ARID REGION OF BRAZIL

    Directory of Open Access Journals (Sweden)

    Carla da Silva Sousa

    2014-03-01

    Full Text Available http://dx.doi.org/10.5902/1980509813331Caatinga is an exclusively Brazilian biome with areas in accentuated process of desertification. Arbuscularmycorrhizal fungi (AMF act in plant succession by favoring the establishment of plant species typical ofsuccessional stages and by accelerating recovery leading to a climax stage. The objective of the present workwas to evaluate the occurrence and diversity of AMF in successional stages of caatinga in the semi-aridregion of Paraíba State. Experimental plots (30 x 60 m were delimitated in 2007 in areas corresponding todifferent caatinga successional stages: early caatinga succession (natural revegetation during the previous15 years; intermediate (natural revegetation for about 35 years; late (mature caatinga with more than50 years without major disturbances; and also in pasture areas fenced and protected to represent the initialphase of succession. Plots of all four stages were implemented with three replicates. Soil and root sampleswere collected in the experimental plots, from the 0-15 cm soil layer in the dry and in the rainy seasons.All areas presented low infectivity potential suggesting that the introduction of mycorrhizal seedlings mayaccelerate the process of revegetation of degraded soils in this region. Except for the areas of late stage, theglomalin reservoirs increased along with the advancement of the succession process. Areas in the late stageof succession presented greater richness of AMF species, indicating that the establishment of the vegetationalso exerts a significant effect in the fungal community. Glomus and Acaulospora species were predominantin both seasons, possibly because they are well adapted to semi-arid conditions

  9. Assessment of the performance of water harvesting systems in semi-arid regions

    Science.gov (United States)

    Lasage, Ralph

    2016-04-01

    Water harvesting is widely practiced and has the potential to improve water availability for domestic and agricultural use in semi-arid regions. New funds are becoming available to stimulate the implementation of water harvesting projects, for meeting the Sustainable Development Goals and to help communities to adapt to climate change. For this, it is important to understand which factors determine the success of water harvesting techniques under different conditions. For this, we review the literature, including information on the crop yield impacts of water harvesting projects in semi-arid Africa and Asia. Results show that large water harvesting structures (> 500 m3) are less expensive than small structures, when taking into account investment costs, storage capacity and lifetimes. We also find that water harvesting improves crop yields significantly, and that the relative impact of water harvesting on crop yields is largest in low rainfall years. We also see that the governance, technical knowledge and initial investment are more demanding for the larger structures than for smaller structures, which may affect their spontaneous adoption and long term sustainability when managed by local communities. To support the selection of appropriate techniques, we present a decision framework based on case specific characteristics. This framework can also be used when reporting and evaluating the performance of water harvesting techniques, which is up to now quite limited in peer reviewed literature. Based on Bouma, J., Hegde, S.E., Lasage, R., (2016). Assessing the returns to water harvesting: A meta-analysis. Agricultural Water Management 163, 100-109. Lasage, R., Verburg P.H., (2015). Evaluation of small scale water harvesting techniques for semi-arid environments. Journal of Arid Environments 118, 48-57.

  10. A Methodology to Assess and Evaluate Rainwater Harvesting Techniques in (Semi-)Arid Regions

    Science.gov (United States)

    Ali, Ammar; Riksen, Michel; Ouessar, Mohamed; Ritsema, Coen

    2015-04-01

    Arid and semi-arid regions around the world are generally facing water scarcity problems due to lack of precipitation and unpredictable rainfall patterns. For thousands of years rainwater harvesting (RWH) techniques have been applied to cope with water scarcity. Many researchers have presented and applied different methodologies for determining suitable sites and techniques for RWH. However, there is still little attention given to evaluation of the performance of RWH structures. The aim of this research was to design a scientifically-based and generally applicable methodology to evaluate and assess the performance of existing RWH techniques in (semi-) arid regions. The methodology takes engineering, biophysical, and socio-economic criteria into account to assess the performance of RWH using the Analytical Hierarchy Process (AHP) supported by Geographic Information System (GIS). The Oum Zessar watershed in south-eastern Tunisia is used as a case study site to test this evaluation tool. The performance of 58 RWH locations (14 jessour and 44 tabias) in three main sub-catchments of Oum Zessar watershed were assessed and evaluated. Based on the criteria selected, 60performance, 36received good performance scores. The results very accurately represent the real performance of each site. This integrated methodology, which is highly flexible, saves time and costs, and is easy to adapt in different regions, provides a scientifically based analytical tool to support designers and decision makers aiming to improve the performance of existing and new RWH sites.

  11. The biogeophysical effect of large-scale afforestation in semi-arid regions

    Science.gov (United States)

    Yosef, Gil; Avissar, Roni; Walko, Robert; Medvigy, David; Yakir, Dan

    2015-04-01

    Forestation in the semi-arid region can significantly influence the surface energy budget and, in turn, the local atmospheric circulations. Such effects could be particularly important in regions under the influence of monsoon regimes, such as the Sahel and North Australia. In these regions, summer solar heating leads first to migration of the equatorial through and the tropical convergence zones (ITCZ) and to the monsoon rain. And second, to a meridional surface temperature gradient that generates low-level easterly jet that acts as a barrier to the penetration of the precipitation into the semi arid areas. In this study we tested the hypothesis that large-scale afforestation in these semi-regions can result in changes in local and regional atmospheric circulation and, consequently, in the precipitation and potential changes in land cover and land use. The GCM OLAM was used to performing high-resolution simulations (50km horizontal grid scale and 50 vertical layers) of afforestation scenarios in the Sahel and North Australia. These areas (Sahel 2.6 E6 km2 and North Australia 2.1 E6 km2) were afforested with a mature pine forest, using the extensive data form the long-term semi-arid Yatir forest in Israel as a reference forest for surface parameterization. The regional effect of the afforestation was analyzed for the following parameters; Surface energy budget, temperature, Easterly jet stream location and intensity, above forest atmospheric instability, water recycling and precipitation. Afforestation in the Sahel resulted in large increase of the surface net radiation (45 W m-2), mainly as a result of decrease in albedo (43 W m-2), decrease of incoming short wave radiation (21 W m-2) and increase of downward long wave radiation (13 W m-2) due to higher clouds cover, and decrease in long wave upward radiation (10 W m-2), as a result of the lower surface temperature. Increasing soil moisture because of the new forest is expressed into higher evapotranspiration, i

  12. Analysis and evaluation of tillage on an alfisol ina semi-arid tropical region of India

    OpenAIRE

    Klaij, M C

    1983-01-01

    Tillage field experiments were conducted on Alfisols in a semi-arid tropical environment in India. The research was conducted within the framework of the Farming Systems Research Program of the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT).To put the experiments into perspective, a general review is given in chapter 2 on the environment of the semi-arid tropics, its problems and the research related to agricultural production. Rainfed agriculture has failed to pro...

  13. Sediment yield assessment by EPM and PSIAC models using GIS data in semi-arid region

    Institute of Scientific and Technical Information of China (English)

    Ali Bagherzadeh; Mohammad Reza Mansouri Daneshvar

    2011-01-01

    Among land degradation processes,soil erosion is the most serious threat to soil and water conservation in semi-arid regions.At the present study,the sedimentation hazard and the erosion zonation were investigated at Kardeh watershed,north-east of Iran by Erosion Potential Method (EPM) and Pacific Sonth-west Inter Agency Committee (PSIAC) models,in combination with the geographical information system (GIS) data,satellite data and field observations.According to our investigation the study area can be categorized into heavy,moderate and slight erosion zones with the total sediment yield of 147859 and 148078 m3/a estimated by EPM and PSIAC models,respectively.The sub-basins located at the middle and south parts of the watershed are highly eroded due to the geology formation and soil erodibility conditions,while the sub-basins at the north parts are moderately eroded because of the intensive land cover.The amounts of the sediment yield in most areas are found to be consistent between the EPM and PSIAC models (R2 = 0.95).Our data suggest the applicability of both empirical models in evaluating the sediment yield in arid and semi-arid watersheds.

  14. New species and records of Anacroneuria (Plecoptera: Perlidae) from the northeastern semi-arid region of Brazil.

    Science.gov (United States)

    Duarte, Tácio; Lecci, Lucas Silveira

    2016-01-01

    The genus Anacroneuria is widely distributed in the Neotropical Region. There are about 80 species listed from Brazil, five of which are recorded from the northeastern semi-arid region of Brazil, an area characterized by irregular and low precipitation. Examination of adult Anacroneuria material from this including areas of Caatinga desert vegetation and Atlantic forest revealed two new species records, A. debilis (Pictet) and A. terere Righi-Cavallaro & Lecci. Additionally, two new species, A. calori n. sp. and A. singela n. sp., are described from this material. These new records and new species reflect a major effort to document the biodiversity of the aquatic insects of the northeastern semi-arid region of Brazil by the Research Program in Semi-arid Biodiversity. PMID:27396007

  15. Weed community and growth under the canopy of trees adapted to the brazilian semi-arid region Comunidade e crescimento de plantas daninhas sob a copa de árvores adaptadas ao semi-árido brasileiro

    Directory of Open Access Journals (Sweden)

    P.S.L. Silva

    2010-01-01

    Full Text Available The objectives of this work were to evaluate the floristic composition and dry biomass of weeds under the canopy of seven perennial species adapted to the Semi-Arid region of Brazil, and correlate these characteristics with growth traits of the perennial species. The following perennial species were evaluated in two experiments (E1 and E2: mesquite (Prosopis juliflora, jucá (Caesalpinia ferrea, white popinac (Leucaena leucocephala, mofumbo (Combretum leprosum, neem (Azadirachata indica, sabiá (Mimosa caesalpiniaefolia and tamarind (Tamarindus indica. In E1, the seven species were evaluated in a random block design with four replicates and nine plants per plot. In E2, evaluation comprised four species (mesquite, jucá, white popinac, and tamarind in a random block design with eight replicates and nine plants per plot. A circle with an area of 1.77 m² was established around the trunk of each plant, two years after they were transplanted to the permanent location. The weeds collected within this circle were cut even with the ground, classified and weighed. At this time, plant height, and crown and stem diameters were evaluated in all trees of each plot. In E1 there were no differences between tree species as to weed frequency under their canopies; however, weed growth was smaller under the canopy of sabiá trees. Mesquite and sabiá had the greatest plant height and crown diameter means, but only sabiá had the greatest stem diameter. In E2, the perennial species were not different with regard to weed frequency and growth under their canopies, but mesquite had the greatest growth, as measured by plant height (with significant results for jucá as well and crown and stem diameter.Os objetivos deste trabalho foram avaliar a composição florística e a biomassa de plantas daninhas sob a copa de sete espécies perenes adaptadas à região semi-árida do Brasil, e correlacionar essas características com características do crescimento das esp

  16. Acupunctural Afforestation for Desertification Mitigation over Semi-Arid Regions in East Asia

    Science.gov (United States)

    Myoung, B.; Choi, Y.; Park, S. K.

    2011-12-01

    Desertification over the arid/semi-arid regions in East Asia and dust transports from the regions have been serious concerns for the societies not only in adjacent Asian countries but also in the western US. One of the strategies for desertification mitigation is tree planting over the semi-arid areas. However, unless the newly planted vegetation changes the feedback characteristics between land-surface and the atmosphere, the impact is not profound and effective for a long time. Here we show afforestation effects on the coupling strength between the land-surface and atmosphere, measured by the monthly anomalies of precipitation and evapotranspiration. The coupling strength is an important parameter to diagnose the aridity of a region since the stronger coupling strength is indicative of the higher vulnerability of the local climate to droughts. Simulations of a regional vegetation-climate coupled model reveal that afforestation substantially modulates local coupling strength mainly through controlling variability of evapotranspiration. The coupling strength decreases most significantly with an increase of unit vegetation fraction over the northern and central China including Manchurian Plains and highly populated areas of Beijing and Tianjin. The coupling characteristics of these regions are expected to reduce the occurrence of extreme weather events such as droughts by alleviating positive responses of the surface to precipitation deficit. Therefore, afforestation concentrated on these regions, which is called "acupunctural afforestation", may most effectively contribute to desertification mitigation than other regions by attenuating mechanisms maintaining warm season droughts. This study suggests that our attention should be paid to understanding the coupling strength between land and the atmosphere for desertification mitigation.

  17. Satellite-based analysis of recent trends in the ecohydrology of a semi-arid region

    Directory of Open Access Journals (Sweden)

    M. Gokmen

    2013-10-01

    Full Text Available We present a regional framework for an integrated and spatiotemporally distributed assessment of human-induced trends in the hydrology and the associated ecological health of a semi-arid basin where both human activities (i.e. agriculture and natural ecosystems are highly groundwater dependent. To achieve this, we analysed the recent trends (from year 2000 to 2010 in precipitation, evapotranspiration (actual and potential and vegetation greenness (i.e. NDVI using a combination of satellite and ground-based observations. The trend assessment was applied for the semi-arid Konya Basin (Turkey, one of the largest endorheic basins in the world. The results revealed a consistent increasing trend of both yearly evapotranspiration (totally 63 MCM yr−1 from croplands and mean NDVI (about 0.004 NDVI yr−1 in irrigated croplands, especially concentrating in the plain part of the basin, while no significant trends were observed for the precipitation and potential evapotranspiration variables. On the contrary, a consistent decreasing trend of both yearly evapotranspiration (totally −2.1 MCM yr−1 and mean NDVI (−0.001 NDVI yr−1 was observed in the wetlands, which also cannot be explained by trends in precipitation and potential evapotranspiration. The emerging picture suggest that the greening trend of the vegetation and increasing of evapotranspiration in the plain are related to land cover changes (i.e. conversion into irrigated croplands and to the intensification of the supplementary irrigation for agriculture, which in turn caused drying out of some wetlands and the natural vegetation which mostly depend on the groundwater, the main source of irrigation water as well. Our study presented an example of the utility of spatially and temporally continuous RS data in assessing the regional trends in hydrological and ecological variables and their interactions in a spatially distributed manner in a semi-arid region, which can also be adapted to

  18. Analysis and evaluation of tillage on an alfisol ina semi-arid tropical region of India

    NARCIS (Netherlands)

    Klaij, M.C.

    1983-01-01

    Tillage field experiments were conducted on Alfisols in a semi-arid tropical environment in India. The research was conducted within the framework of the Farming Systems Research Program of the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT).To put the experiments into per

  19. Agricultural water productivity optimization for irrigated Teff (Eragrostic Tef) in water scarce semi-arid region of EthiopiaAgricultural water productivity optimization for irrigated Teff (Eragrostic Tef) in water scarce semi-arid region of Ethiopia

    NARCIS (Netherlands)

    Yihun, Y.M.

    2015-01-01

    Title of the PhD Thesis: ‘Agricultural Water Productivity Optimization for Irrigated Teff (Eragrostic Tef) in water Scarce Semi-Arid region of Ethiopia’ Yenesew Mengiste Yihun In water stressed regions such as the Central Rift Valley of Ethiopia, increasing Crop Water Productivity (CWP)

  20. Isotope techniques in water resource investigations in arid and semi-arid regions

    International Nuclear Information System (INIS)

    The Co-ordinated Research Project (CRP) on the Use of Isotope Techniques in Water Resources Investigations in Arid and Semi-arid Regions was initiated with the aim od contributing to the assessment of groundwater resources in arid areas through the use of environmental isotope techniques, and thereby to help in better management of these valuable fresh groundwater resources. The main emphases identified were in three key areas: (i) the evaluation of water balance components such as recharge rate estimation and recharge and discharge cycles at different spatial scales, (ii) paleohydrology and hydroclimatic change and, (iii) anthropogenic impacts and the assessment of the vulnerability of arid zone ground waters to salinisation and pollution impacts. This publication presents individual projects carried out within the frameworks of the CRP. Each paper has been indexed separately

  1. [Effect of Biochar on Soil Greenhouse Gas Emissions in Semi-arid Region].

    Science.gov (United States)

    Guo, Yan-liang; Wang, Dan-dan; Zheng, Ji-yong; Zhao, Shi-wei; Zhang, Xing-chang

    2015-09-01

    This study aimed to investigate the effects of biochar addition on the emission of greenhouse gases from farmland soil in semi-arid region. Through an in-situ experiments, the influence of sawdust biochar(J) and locust tree skin biochar (H) at three doses (1%, 3%, and 5% of quality percentage) on C2, CH4 and N2O emissions were studied within the six months in the south of Ningxiaprovince. The results indicated that soil CO2 emission flux was slightly increased with the addition doses for both biochars, and the averaged CO2 emission flux for sawdust and locust tree skin biochar was enhanced by 1. 89% and 3. 34% compared to the control, but the difference between treatments was not statistically significant. The soil CH4 emission was decreased with the increasing of biochar doses, by 1. 17%, 2. 55%, 4. 32% for J1, J3, J5 and 2. 35%, 5. 83%, 7. 32% for H1, H3, H5, respectively. However, the difference was statistically significant only for J5, H3 and H5 treatments (P effect on soil N2O emission. Our study indicated that the biochar has no significant influence on soil CO2 and N2O emissions within six months in semi-arid region and can significantly influence soil CH4 emissions (P < 0. 05). As for biochar type, the locust tree skin biochar is significantly better than the sawdust biochar in terms of restraining CH4 emission(P = 0. 048). PMID:26717703

  2. [Effect of Biochar on Soil Greenhouse Gas Emissions in Semi-arid Region].

    Science.gov (United States)

    Guo, Yan-liang; Wang, Dan-dan; Zheng, Ji-yong; Zhao, Shi-wei; Zhang, Xing-chang

    2015-09-01

    This study aimed to investigate the effects of biochar addition on the emission of greenhouse gases from farmland soil in semi-arid region. Through an in-situ experiments, the influence of sawdust biochar(J) and locust tree skin biochar (H) at three doses (1%, 3%, and 5% of quality percentage) on C2, CH4 and N2O emissions were studied within the six months in the south of Ningxiaprovince. The results indicated that soil CO2 emission flux was slightly increased with the addition doses for both biochars, and the averaged CO2 emission flux for sawdust and locust tree skin biochar was enhanced by 1. 89% and 3. 34% compared to the control, but the difference between treatments was not statistically significant. The soil CH4 emission was decreased with the increasing of biochar doses, by 1. 17%, 2. 55%, 4. 32% for J1, J3, J5 and 2. 35%, 5. 83%, 7. 32% for H1, H3, H5, respectively. However, the difference was statistically significant only for J5, H3 and H5 treatments (P effect on soil N2O emission. Our study indicated that the biochar has no significant influence on soil CO2 and N2O emissions within six months in semi-arid region and can significantly influence soil CH4 emissions (P < 0. 05). As for biochar type, the locust tree skin biochar is significantly better than the sawdust biochar in terms of restraining CH4 emission(P = 0. 048).

  3. Determine the optimum spectral reflectance of juniper and pistachio in arid and semi-arid region

    Science.gov (United States)

    Fadaei, Hadi; Suzuki, Rikie

    2012-11-01

    Arid and semi-arid areas of northeast Iran cover about 3.4 million ha are populated by two main tree species, the broadleaf Pistacia vera. L (pistachio) and the conifer Juniperus excelsa ssp. polycarpos (Persian juniper). Natural stands of pistachio in Iran are not only environmentally important but genetically essential as seed sources for pistachio production in orchards. In this study, we estimated the optimum spectral reflectance of juniper forests and natural pistachio stands using remote sensing to help in the sustainable management and production of pistachio in Iran. In this research spectral reflectance are able to specify of multispectral from Advanced Land Observing Satellite (ALOS) that provided by JAXA. These data included PRISM is a panchromatic radiometer with a 2.5 m spatial resolution at nadir, has one band with a wavelength of 0.52-0.77 μm and AVNIR-2 is a visible and near infrared radiometer for observing land and coastal zones with a 10 m spatial resolution at nadir, has four multispectral bands: blue (0.42-0.50 μm), green (0.52-0.60 μm), red (0.61-0.69 μm), and near infrared (0.76-0.89 μm). Total ratio vegetation index (TRVI) of optimum spectral reflectance of juniper and pistachio have been evaluated. The result of TRVI for Pistachio and juniper were (R2= 0.71 and 0.55). I hope this research can provide decision of managers to helping sustainable management for arid and semi-arid regions in Iran.

  4. The current bioenergy production potential of semi-arid and arid regions in sub-Saharan Africa

    NARCIS (Netherlands)

    Wicke, B.; Smeets, E.M.W.; Watson, H.; Faaij, A.P.C.

    2011-01-01

    This article assesses the current technical and economic potential of three bioenergy production systems (cassava ethanol, jatropha oil and fuelwood) in semi-arid and arid regions of eight sub-Saharan African countries. The results indicate that the availability of land for energy production ranges

  5. Alternative Crop Rotations in the Semi-arid Central Great Plains Region: How Much Fallow? Evaluating the Economics

    Science.gov (United States)

    The traditional crop production system in the semi-arid Central Great Plains Region (CGPR) of the U.S.A. is winter wheat (Triticum aestivum L.)-summer fallow (WF) or one crop every two years. This system is not a long-term sustainable dryland system. It is conducive to soil degradation and provide...

  6. Regional integrated modelling of climate change impacts on natural resources and resource usage in semi-arid Northeast Brazil

    NARCIS (Netherlands)

    Krol, Maarten S.; Bronstert, Axel

    2007-01-01

    Semi-arid regions are characterised by a high vulnerability of natural resources to climate change, pronounced climatic variability and often by water scarcity and related social stress. The analysis of the dynamics of natural conditions and the assessment of possible strategies to cope with drought

  7. Mechanisms, timing and quantities of recharge to groundwater in semi-arid and tropical regions

    International Nuclear Information System (INIS)

    Groundwater being exploited in many and and semi-arid regions at the present day was recharged during former humid episodes of the Pleistocene or Holocene and, in contrast, the amounts derived from modem recharge are small generally small and variable. Geochemical and isotopic techniques provide the most effective way to calculate modem recharge and to investigate recharge history, since physically- based water-balance methods are generally inapplicable in semiarid regions. Examples from Africa (Senegal, Niger, Nigeria, Sudan as well as Cyprus) show that direct recharge rates may vary from zero to around 40% of mean rainfall, dependent primarily on the soil depth and the lithology. Spatial variability presents a real problem in any recharge investigation but results from Senegal show that unsaturated zone profiles may be extrapolated using the chemistry of shallow groundwater. Unsaturated-zone studies show that there are limiting conditions to direct recharge through soil, but that present day replenishment of aquifers takes place via wadis and channels. In the Butana area of central Sudan the regional groundwater was also recharged during a mid-Holocene wet phase and is now in decline. The only current recharge sources, which can be recognised distinctly using stable isotopes, are Nile baseflow and ephemeral wadi floods. (author)

  8. Improving Modeling of the Summer Climate of Semi-Arid Regions

    Science.gov (United States)

    Eltahir, E.; Marcella, M.

    2009-04-01

    Presented is a study on the importance of certain land surface processes in accurately simulating the summertime climate of Southwest Asia. A nearly 4 degree C bias is simulated in summertime temperatures, by standard Regional Climate Model version 3 (RegCM3). Biases are also found in surface albedo, shortwave incident, and surface vapor pressure. Using satellite data, (Earth Radiation Budget Experiment-ERBE) modifications are introduced to match simulated surface albedo to the ERBE data. In addition, by incorporating RegCM3's dust module with sub-grid variability, surface shortwave incident biases are reduced. Lastly, representing the irrigation and marshlands of Mesopotamia reduces vapor pressure deficits in the region. All of these factors combined, along with errors in observational datasets, account for the 4 degree C warm bias in RegCM3 simulations. We conclude that accurate representations of albedo, irrigation, and dust emissions are important processes to be included for accurate summertime climate modeling in semi-arid regions around the world.

  9. Genetic resistance to natural coccidiosis infection in goats in a semi-arid region of India

    Directory of Open Access Journals (Sweden)

    P.K. Rout

    2015-12-01

    Full Text Available Coccidiosis is one of the major causes of kid mortality in tropical regions and causes significant loss to farmers by affecting growth and feed efficiency in the growing kid. The strategy to control the coccidiosis is mainly through drug usage and is not efficacious at present. Therefore, an alternative strategy is required to control the disease in goats. Increasing genetic resistance to coccidiosis may be an appropriate complementary control strategy. The purpose of this study was to analyse the genetic variation in severity of natural coccidiosis infections in kids in the semi-arid region. The observations were recorded in 227 kids of Barbari and Jamunapari goats. Barbari goats had higher mean faecal oocyst counts (FOC than Jamunapari goats at 3 and 6 months of age. The heritability for FOC was 0.05 and 0.15 at 3 and 6 months of age, respectively. All phenotypic and environmental correlations between FOC and live weight traits were low and negative, indicating a tendency for more heavily infected kids in the flock to grow more slowly. Genetic correlations were largely similar, but had large standard errors. The results suggest that genetic resistance control strategy can potentially be useful for the better performance in the existing managemental condition.

  10. Predictability and prediction of summer rainfall in the arid and semi-arid regions of China

    Science.gov (United States)

    Xing, Wen; Wang, Bin

    2016-09-01

    Northwest China (NWC) is an arid and semi-arid region where climate variability and environmental changes are sensitive to precipitation. The present study explores sources and limits of predictability of summer precipitation over NWC using the predictable mode analysis (PMA) of percentage of rainfall anomaly data. Two major modes of NWC summer rainfall variability are identified which are tied to Eurasian continental scale precipitation variations. The first mode features wet northern China corresponding to dry central Siberia and wet Mongolia, which is mainly driven by tropical Pacific sea surface temperature anomalies (SSTA). The second mode features wet western China reflecting wet Central Asia and dry Ural-western Siberia, which strongly links to Indian Ocean SSTA. Anomalous land warming over Eurasia also provides important precursors for the two modes. The cross-validated hindcast results demonstrate these modes can be predicted with significant correlation skills, suggesting that they may be considered as predictable modes. The domain averaged temporal correlation coefficient (TCC) skill during 1979 to 2015 using 0-month (1-month) lead models is 0.39 (0.35), which is considerably higher than dynamical models' multi-model ensemble mean skill (-0.02). Maximum potential attainable prediction skills are also estimated and discussed. The result illustrates advantage of PMA in predicting rainfall over dry land areas and large room for dynamical model improvement. However, secular changes of predictors need to be detected continuously in order to make practical useful prediction.

  11. Peach response to water deficit in a semi-arid region

    Science.gov (United States)

    Paltineanu, C.; Septar, L.; Moale, C.; Nicolae, S.; Nicola, C.

    2013-09-01

    During three years a deficit irrigation experiment was performed on peach response under the semi-arid conditions of south-eastern Romania. Three sprinkler-irrigated treatments were investigated: fully irrigated, deficit irrigation treatment, and non-irrigated control treatment. Soil water content ranged between 60 and 76% of the plant available soil water capacity in fully irrigated, between 40 and 62% in deficit irrigation treatment, and between 30 and 45% in control. There were significant differences in fruit yield between the treatments. Irrigation water use efficiency was maximum in deficit irrigation treatment. Fruit yield correlated significantly with irrigation application. Total dry matter content, total solids content and titrable acidity of fruit were significantly different in the irrigated treatments vs. the control. Significant correlation coefficients were found between some fruit chemical components. For the possible future global warming conditions, when water use becomes increasingly restrictive, deficit irrigation will be a reasonable solution for water conservation in regions with similar soil and climate conditions.

  12. Characterization of Pseudomonas Species Isolated from the Rhizosphere of Plants Grown in Serozem Soil, Semi-Arid Region of Uzbekistan

    OpenAIRE

    Dilfuza Egamberdiyeva

    2005-01-01

    Collections of native Pseudomonas spp. are kept at the NCAM of Uzbekistan. Some of those organisms were isolated from the rhizosphere of cotton, wheat, corn, melon, alfalfa, and tomato grown in field locations within a semi-arid region of Uzbekistan. Strains used for this study were Pseudomonas alcaligenes, P. aurantiaca, P. aureofaciens, P. denitrificans, P. mendocina, P. rathonis, and P. stutzeri. Some of the pseudomonads have been characterized in this report. These strains produced enzyme...

  13. Linking Bayesian and agent-based models to simulate complex social-ecological systems in semi-arid regions

    OpenAIRE

    Pope, Aloah J.; Gimblett, Randy

    2015-01-01

    Interdependencies of ecologic, hydrologic, and social systems challenge traditional approaches to natural resource management in semi-arid regions. As a complex social-ecological system, water demands in the Sonoran Desert from agricultural and urban users often conflicts with water needs for its ecologically-significant riparian corridors. To explore this system, we developed an agent-based model to simulate complex feedbacks between human decisions and environmental conditions in the Rio So...

  14. Linking Bayesian and agent-based models to simulate complex social-ecological systems in semi-arid regions

    OpenAIRE

    Pope, Aloah J.; Randy eGimblett

    2015-01-01

    Interdependencies of ecologic, hydrologic, and social systems challenge traditional approaches to natural resource management in semi-arid regions. As a complex social-ecological system, water demands in the Sonoran Desert from agricultural and urban users often conflicts with water needs for its ecologically-significant riparian corridors. To explore this system, we developed an agent-based model to simulate complex feedbacks between human decisions and environmental conditions in the Rio ...

  15. Decomposição e liberação de nutrientes de coquetéis vegetais para utilização no Semiárido brasileiro The decomposition and release of nutrients by plant mixtures in the Brazilian semi-arid regions

    Directory of Open Access Journals (Sweden)

    Vanderlise Giongo

    2011-09-01

    Full Text Available A decomposição e liberação de nutrientes de resíduos vegetais podem assumir importante papel no manejo da fertilidade dos solos da região semiárida. Portanto, o presente estudo teve por objetivo avaliar a taxa de decomposição da matéria seca (MS e liberação de carbono (C e nutrientes de coquetéis vegetais no Semiárido brasileiro. O experimento foi conduzido em casa de vegetação, no período de novembro de 2007 a junho de 2008, com coquetéis vegetais compostos por espécies de leguminosas (L (calopogônio, Crotalaria juncea, Crotalaria spectabilis, feijão de porco, guandu, lab-lab e não leguminosas (NL (gergelim, girassol, mamona, milheto e sorgo, combinados nos seguintes tratamentos: T1 - 100% NL; T2 - 100% L; T3 - 75% L e 25% NL; T 4 - 50% L e 50% NL; T5 - 25% L e 75% NL. As taxas de decomposição da MS e liberação dos nutrientes foram monitoradas por meio de coleta dos resíduos, realizadas aos 8; 15; 30; 60; 90; 120; 150; 180 e 210 dias após o início do experimento. Utilizou-se o delineamento experimental em blocos casualizados com três repetições. Os coquetéis apresentaram taxas de decomposição de MS e liberação de nutrientes semelhantes, exceto para Ca, Cu e Mn, em que os coquetéis compostos com predominância de espécies NL apresentaram liberação mais rápida. A partir da média dos valores de k para todos os coquetéis estabeleceu-se a seguinte ordem de liberação de macronutrientes: K > N > Ca > Mg > P e de micronutrientes: Fe > Mn > Cu > Zn > B.The decomposition and release of nutrients from plant residues can play an important role in the maintenance of soil fertility in semi-arid regions. Thus this study aimed to evaluate the rate of decomposition of dry matter (DM and the release of carbon (C and nutrients from plant mixtures used as green manure in the Brazilian Semi-arid regions. The experiment was carried out in a greenhouse, from November 2007 to July 2008, using plant mixtures made up of

  16. Integrated Water Resources Planning and Management in Arid/Semi-arid Regions: Data, Modeling, and Assessment

    Science.gov (United States)

    Gupta, H.; Liu, Y.; Wagener, T.; Durcik, M.; Duffy, C.; Springer, E.

    2005-12-01

    Water resources in arid and semi-arid regions are highly sensitive to climate variability and change. As the demand for water continues to increase due to economic and population growth, planning and management of available water resources under climate uncertainties becomes increasingly critical in order to achieve basin-scale water sustainability (i.e., to ensure a long-term balance between supply and demand of water).The tremendous complexity of the interactions between the natural hydrologic system and the human environment means that modeling is the only available mechanism for properly integrating new knowledge into the decision-making process. Basin-scale integrated models have the potential to allow us to study the feedback processes between the physical and human systems (including institutional, engineering, and behavioral components); and an integrated assessment of the potential second- and higher-order effects of political and management decisions can aid in the selection of a rational water-resources policy. Data and information, especially hydrological and water-use data, are critical to the integrated modeling and assessment for water resources management of any region. To this end we are in the process of developing a multi-resolution integrated modeling and assessment framework for the south-western USA, which can be used to generate simulations of the probable effects of human actions while taking into account the uncertainties brought about by future climatic variability and change. Data are being collected (including the development of a hydro-geospatial database) and used in support of the modeling and assessment activities. This paper will present a blueprint of the modeling framework, describe achievements so far and discuss the science questions which still require answers with a particular emphasis on issues related to dry regions.

  17. Holocene semi-arid oak woodlands in the Irano-Anatolian region of Southwest Asia: natural or anthropogenic?

    Science.gov (United States)

    Asouti, Eleni; Kabukcu, Ceren

    2014-04-01

    It is commonly accepted that, following the end of the Pleistocene, semi-arid deciduous oak woodlands did not spread in the Irano-Anatolian region of Southwest Asia as quickly as they did in the Levantine Mediterranean littoral, despite the fact that climatic improvement occurred broadly at the same time in both regions. Prehistoric impacts on woodland vegetation (such as woodcutting, burning and clearance for cultivation), the harsh continental climate of inland Southwest Asia and its distance from late Pleistocene arboreal refugia have all been discussed in the literature as likely causes of the delay. In this paper we argue that semi-arid deciduous oak woodlands should not be viewed as part of the “natural” vegetation of the Irano-Anatolian region that has been progressively destroyed by millennia of human activities since the Neolithic. They represent instead one of the earliest anthropogenic vegetation types in Southwest Asia, one that owes its very existence to prehistoric landscape practices other scholars commonly label as “destructive”. Drawing on anthracological, pollen and modern vegetation data from central Anatolia we describe how the post-Pleistocene species-rich and structurally diverse temperate semi-arid savanna grasslands were gradually substituted by low-diversity, even-aged Quercus-dominated parklands and wood pastures in the course of the early Holocene. Economic strategies that encouraged the establishment and spread of deciduous oaks included sheep herding that impacted on grass and forb vegetation, the controlling of competing arboreal vegetation through woodcutting, and woodland management practices such as coppicing, pollarding and shredding that enhanced Quercus vegetative propagation, crown and stem growth. Understanding the origin and evolution of the Irano-Anatolian semi-arid oak woodlands of Southwest Asia is of critical importance for reconstructing the changing ecologies and geographical distributions of the progenitors of

  18. Controlling stomatal aperture in semi-arid regions-The dilemma of saving water or being cool?

    Science.gov (United States)

    Chaves, M M; Costa, J M; Zarrouk, O; Pinheiro, C; Lopes, C M; Pereira, J S

    2016-10-01

    Stomatal regulation of leaf gas exchange with the atmosphere is a key process in plant adaptation to the environment, particularly in semi-arid regions with high atmospheric evaporative demand. Development of stomata, integrating internal signaling and environmental cues sets the limit for maximum diffusive capacity of stomata, through size and density and is under a complex genetic control, thus providing multiple levels of regulation. Operational stomatal conductance to water vapor and CO2 results from feed-back and/or feed-forward mechanisms and is the end-result of a plethora of signals originated in leaves and/or in roots at each moment. CO2 assimilation versus water vapor loss, proposed to be the subject of optimal regulation, is species dependent and defines the water use efficiency (WUE). WUE has been a topic of intense research involving areas from genetics to physiology. In crop plants, especially in semi-arid regions, the question that arises is how the compromise of reducing transpiration to save water will impact on plant performance through leaf temperature. Indeed, plant transpiration by providing evaporative cooling, is a major component of the leaf energy balance. In this paper we discuss the dilemma of 'saving water or being cool' bringing about recent findings from molecular genetics, to development and physiology of stomata. The question of 'how relevant is screening for high/low WUE in crops for semi-arid regions, where drought and heat co-occur' is discussed. PMID:27593463

  19. Monitoring small reservoirs in semi-arid region by satellite SAR data

    Science.gov (United States)

    Nicolina Papa, Maria; Mitidieri, Francesco; Amitrano, Donato; Ruello, Giuseppe; Di Martino, Gerardo; Iodice, Antonio; Riccio, Daniele

    2016-04-01

    The work presents a novel tool for the monitoring of small reservoirs in semi-arid regions. The pilot project was developed in the Yatenga region, a Sahelian area in northern Burkina Faso. In semi-arid regions, small reservoirs are widely employed for facing seasonal variability in water availability due to the alternation of a rainy (3 months) and a dry (9 months) season. Beside their crucial importance, the small reservoirs are not appropriately monitored, they are often built for the initiative of small local communities and even basic data as their location and capacity are not available. Another major problem is linked to soil erosion due to water and consequent reservoirs' sedimentation that reduces the amount of available water and the life span of reservoirs. This lack of data prevents the implementation of strategies for the optimization of water resources management. It is therefore necessary to improve the data availability through the development of cost-effective monitoring techniques and to adapt the hydrological modeling to the limited available data. In this context the use if satellite data can highly contribute to the achievement of crucial information at low costs, high resolution in time and wide areas. In the present work, we used COSMO-SkyMed Stripmap (3m resolution) and Spotligth (1m resolution) Synthetic Aperture Radar (SAR) data acquired under the aegis of the 2007 Italian Space Agency Announcement of Opportunity and of the HydroCIDOT project. The shorelines of the reservoirs were extracted from the series of SAR images by employing an innovative change-detection framework. A digital elevation model (DEM) of the study area was obtained via standard interferometry processing of images acquired at the end of the dry season, when small reservoirs are completely empty, and information about the surface usually covered by water can be retrieved. The obtained DEM and shorelines were used for bathymetry extraction of reservoirs. For the

  20. Theoretical simulation of small scale psychometric solar water desalination system in semi-arid region

    International Nuclear Information System (INIS)

    Many countries around the world suffer from water scarcity. This is especially true in remote and semi-arid regions in the Middle East and North Africa (MENA) where per capita water supplies decline as populations increase. This paper presents the results of a theoretical simulation of an affordable small scale solar water desalination plant using the psychometric humidification and dehumidification process coupled with an evacuated tube solar collector with an area of about 2 m2. A mathematical model was developed to describe the system's operation. Then a computer program using Simulink Matlab software was developed to provide the governing equations for the theoretical calculations of the humidification and dehumidification processes. The experimental and theoretical values for the total daily distillate output were found to be closely correlated. After the experimental calibration of the mathematical model, a model simulating solar radiation under the climatic conditions in the Middle East region proved that the performance of the system could be improved to produce a considerably higher amount of fresh water, namely up to 17.5 kg/m2 day. This work suggests that utilizing the concept of humidification and dehumidification, a compact water desalination unit coupled with solar collectors would significantly increase the potable water supply in remote area. It could be a unique solution of water shortages in such areas. -- Highlights: • An affordable small scale desalination system is proposed. • A mathematical model of the desalination system is developed and programmed using Matlab Simulink. • The model describes the psychometric process based on humidification and dehumidification. • The model is used in optimal selection of elements and operating conditions for solar desalination system. • The use of solar water desalination contributes significantly to reducing global warming

  1. Carbon dioxide and methane supersaturation in lakes of semi-humid/semi-arid region, Northeastern China

    Science.gov (United States)

    Wen, Zhidan; Song, Kaishan; Zhao, Ying; Jin, Xiuliang

    2016-08-01

    Understanding concentrations of carbon dioxide (CO2) and methane (CH4) in lakes is an important part of a comprehensive global carbon budget. We estimated data on the partial pressure of CO2 (pCO2) and CH4 (pCH4) from sampling with 95 lakes in semi-humid/semi-arid region of Northeastern China during ice-free period. Both pCO2 and pCH4 varied greatly among the study sites. p(CO2) values in these lakes ranged from 21.9 to 30,152.3 μatm (n = 403), and 91% of lakes in this survey were supersaturated with CO2. p(CH4) values ranged from 12.6 to 139,630.7 μatm with all sites in this study of CH4 sources to the atmosphere during the ice-free period. The collected urban lakes samples exhibited higher pCO2 and pCH4 than wild lakes samples. Either the mean value of p(CO2) or p(CH4) in saline waters is higher than in fresh waters. Correlation analysis implied that the partial pressure of the GHGs (CO2 and CH4) showed statistically correlations with water environment indicators like pH, dissolved organic carbon (DOC), total nitrogen (TN), total phosphorus (TP), and chlorophyll a (Chla). However, the most of the relationships showed a high degree of scatter, only pH might be used as the predictor of the gas partial pressure based on the result of this study (rpCO2 = -0.437, p carbon emission rate is 560.2 g C m-2 from 95 lakes in Northeastern China. We could not extrapolate carbon emission from these lakes to the boreal region or a wider scale because of the change of environmental conditions.

  2. Modelling long-term sustainability of irrigation practices in semi arid region

    Science.gov (United States)

    Guyennon, Nicolas; Romano, Emanuele; Portoghese, Ivan

    2016-04-01

    The impact of climate change on groundwater or surface water resources can be investigated through models simulating the hydrological and hydrogeological processes at the atmosphere/surface water/soil/groundwater interfaces. However, in aquifers extensively exploited for irrigation purposes, the water demand variability related to actual water availability, as well as to variation of the crops, and associated supply management options should be considered to evaluate impacts. Moreover, in the case of a multi-resources water supply system it is necessary to develop models able to simulate also the variation of the total demand distribution among each resource. We proposed a modeling scheme able to simulate an integrated multiple-resources and multiple-purposes water supply system by merging distributed crop water requirements with surface reservoir and ground water mass balance, considering resources availability and management, with emphasis on irrigation practices. The overall framework has been implemented for the case study of the Fortore water supply system, a semi-arid region in south Italy. It permits to simulate the conjunctive use of the water from the Occhito artificial reservoir (160 Mm3) and from groundwater to supply domestic, industrial and agricultural demand. The overall model successfully reproduces the Occhito dam level variability (both seasonal and inter-annual) as well as the observed groundwater depletion. The proposed model was forced by 60 years of meteorological observation to test the long-term sustainability of the current irrigation practices and has been extended to the next decades under a1b IPCC scenario using three ENSEMBLES member to test adaptation strategies.

  3. Disponibilidade familiar de alimentos na Zona da Mata e Semi-Árido do Nordeste do Brasil Household food availability in the Forest Zone (Zona da Mata and Semi-Arid Brazilian Northeast regions

    Directory of Open Access Journals (Sweden)

    Mônica Maria Osório

    2009-06-01

    Full Text Available OBJETIVO: Este trabalho teve como objetivo caracterizar a disponibilidade de alimentos em domicílios de Gameleira (PE e São João do Tigre (PB, municípios das referidas regiões, considerando a freqüência dos alimentos, o número de pessoas no domicílio e a escolaridade do chefe da família. MÉTODOS: A amostra foi constituída de 502 e 458 famílias, em Gameleira (PE e São João do Tigre (PB, respectivamente, de área urbana e rural de cada município. As informações, referentes aos sete dias anteriores à entrevista, foram fornecidas pelo responsável pela preparação dos alimentos. RESULTADOS: Verifica-se a disponibilidade de 33 alimentos em Gameleira (PE e 30 em São João do Tigre (PB, em mais de 20% das famílias; restringindo-se a 16 e 15 alimentos nos dois municípios respectivamente, quando considerada a disponibilidade em 50% das famílias. Os alimentos disponíveis na maioria dos domicílios possuíam alto valor energético e pertenciam aos grupos de cereais e leguminosas, em detrimento de hortaliças, frutas e produtos de origem animal. A disponibilidade alimentar sofreu pouca variação em decorrência do número de pessoas no domicílio e da escolaridade do chefe da família. CONCLUSÃO: O estímulo ao aumento qualitativo e quantitativo da disponibilidade familiar de alimentos deve ser o foco dos esforços governamentais em programas sociais de combate à fome.OBJECTIVE: The purpose of this study was to determine household food availability in Gameleira (PE and São João do Tigre (PB, municipalities in the abovementioned regions, taking into account the frequency of food consumption, number of people per household, and education level of the head of the household. METHODS: The sample consisted of 502 and 458 families in Gameleira (PE and São João do Tigre (PB, respectively, living in both urban and rural areas. Information on food consumption during the seven days prior to the interview was provided by the person in

  4. Occurrence and identification of the etiologic agents of plant diseases in cactus (Opuntia ficus-indica Mill.) in the semi-arid region of Paraiba

    OpenAIRE

    Anne Evelyne Franco de Souza; Luciana Cordeiro Nascimento; Egberto Araújo; Edson Batista Lopes; Francisca Maria Souto

    2010-01-01

    Cactus forage (Opuntia ficus-indica Mill.), intensely cultivated in dry regions of northeast Brazil, although well adapted to the harsh semi-arid climate is affected by major problems such as pests and diseases, responsible for significant losses in production. This study aimed to investigate the occurrence and diversity of the etiologic agents of diseases of cactus cultivated in 38 municipalities in the semi-arid region of Paraiba. The analyses were conducted and processed at the Laboratory ...

  5. Sustainable Land Management in African Semi-arid and Subhumid Regions: Proceedings of the SCOPE Workshop, Dakar, Senegal, 15-19 November 1993

    OpenAIRE

    Ganry, F.; Campbell, B.

    1995-01-01

    Metadata only record Maintaining the natural resource base over time in dryland areas of the tropics (which cover the arid, semi-arid, and subhumid regions) requires that desertification and land degradation be controlled. Because of their areal importance, on a global scale, their potential for food and wood production, and their vulnerability, the semi-arid regions, in particular of Africa, are of special importance. The book contains the proceedings of a SCOPE (Scientific Committee on P...

  6. ENERGETIC VALUE OF FORAGES FROM SEMI-ARID REGION AND DIGESTIBILITY OF RATIONS FOR NAKED NECK PULLETS

    Directory of Open Access Journals (Sweden)

    ALEX MARTINS VARELA DE ARRUDA

    2014-01-01

    Full Text Available The feeding programs for naked neck chickens in semi-intensive production system from brazilian equatorial semi-arid environment, must consider regional food availability and respective nutritional values. Thus, to evaluate the digestibility and metabolizable energy of alternative forages, it was used 240 naked neck pullets (Isa Label lineage receiving water and ration ad libitum, pair-housed in cages for total collection of excreta on conventional warehouse. It was used a completely randomized design with factorial arrangement (5x2: one control ration (corn and soy meal and other four experimental rations with silk flower hay (Calotropis procera, cassava leafs hay (Manihot esculenta, kills pasture hay (Senna obtusifolia or leucaena leafs hay (Leucaena leucocephala, and all rations were balanced for two growing phases, between 8 and 10 weeks (young pullets and between 14 and 16 weeks of age (old pullets. The values of apparent digestibility of nutrients for all experimental rations were lower than control ration (P <0.05 and it was observed general means of 72.18% for dry matter, 78.12% for crude protein, 66.90% for ether extract, 28.08% for neutral detergent fiber, 18.51% for the acid detergent fiber, 71.64% for gross energy and availability of 15.61% for mineral matter. The general mean of apparent and corrected metabolizable energy of alternative forages was 1217 kcal/ kg and 1108 kcal/kg, respectively, and the higher value was determined for leucaena hay and the lower value for silk flower hay (P <0.05.

  7. Keeping Sediment and Nutrients out of Streams in Arid/Semi-Arid Regions: Application of Low Impact Development/Green Infrastructure Practices

    Science.gov (United States)

    Yongping, Yuan

    2015-04-01

    Climatic and hydrological characteristics in the arid/semi-arid areas create unique challenges to soil, water and biodiversity conservation. These areas are environmentally sensitive, but very valuable for the ecosystems services they provide to society. Some of these areas are experiencing the fastest urbanization and now face multiple water resource challenges. Low Impact Development (LID)/Green Infrastructure (GI) practices are increasingly popular for reducing stormwater and nonpoint source pollution in many regions around the world. However, streamflow in the arid/semi-arid regions is largely dependent on seasonal, short term, and high intensity rainfall events. LID has not been very common in the arid/semi-arid regions due to a lack of performance evaluation, as well as the perception that LID may not be very useful for regions with little annual precipitation. This study focused on investigating the hydrologic and pollutant removal performance of LID/GI systems in arid/semi-arid climates. Ten types of practices were found in use in the Western/Southwestern U.S.: rainwater harvest systems, detention ponds, retention ponds, bioretention, media filters, porous pavements, vegetated swales/buffer/strips, green roofs, infiltration trenches, and integrated LIDs. This study compared the performance of these practices in terms of their effectiveness at pollutant removal and cost-effectiveness. This analysis provides insight into the future implementation of LID/GI in the arid/semi-arid areas. Key words: LID/GI, arid/semi-arid, effectiveness of pollutant removal, cost-effectiveness analysis

  8. Carbon dioxide and methane supersaturation in lakes of semi-humid/semi-arid region, Northeastern China

    Science.gov (United States)

    Wen, Zhidan; Song, Kaishan; Zhao, Ying; Jin, Xiuliang

    2016-08-01

    Understanding concentrations of carbon dioxide (CO2) and methane (CH4) in lakes is an important part of a comprehensive global carbon budget. We estimated data on the partial pressure of CO2 (pCO2) and CH4 (pCH4) from sampling with 95 lakes in semi-humid/semi-arid region of Northeastern China during ice-free period. Both pCO2 and pCH4 varied greatly among the study sites. p(CO2) values in these lakes ranged from 21.9 to 30,152.3 μatm (n = 403), and 91% of lakes in this survey were supersaturated with CO2. p(CH4) values ranged from 12.6 to 139,630.7 μatm with all sites in this study of CH4 sources to the atmosphere during the ice-free period. The collected urban lakes samples exhibited higher pCO2 and pCH4 than wild lakes samples. Either the mean value of p(CO2) or p(CH4) in saline waters is higher than in fresh waters. Correlation analysis implied that the partial pressure of the GHGs (CO2 and CH4) showed statistically correlations with water environment indicators like pH, dissolved organic carbon (DOC), total nitrogen (TN), total phosphorus (TP), and chlorophyll a (Chla). However, the most of the relationships showed a high degree of scatter, only pH might be used as the predictor of the gas partial pressure based on the result of this study (rpCO2 = -0.437, p < 0.01, n = 382; rpCH4 = -0.265, p < 0.01, n = 400). Furthermore, salinity could be a good predictor for p(CO2) and p(CH4) in 83 freshwater lakes in our study (rpCO2 = 0.365, rpCH4 = 0.323, p < 0.01, n = 348). The mean CO2 flux increased with the decreasing lake area size. The calculated annual areal carbon emission rate is 560.2 g C m-2 from 95 lakes in Northeastern China. We could not extrapolate carbon emission from these lakes to the boreal region or a wider scale because of the change of environmental conditions.

  9. Reconstruction of paleohydrology in semi-arid regions for water resources management: Opportunities and challenges

    Science.gov (United States)

    Elshorbagy, Amin; Wagener, Thorsten; Razavi, Saman; Sauchyn, David

    2016-04-01

    Tree-ring based reconstruction of paleohydrology can be a valuable and important means to extend the available hydrological records for several centuries. Such record extension, when properly done, can improve water resources management and planning by making available realistic long records that reflect past short- and long-term hydrometeorological variabilities. This research highlights some of the important, and perhaps unresolved, issues in tree-ring based reconstruction of paleohydrology, especially in semi-arid regions. The relationships between tree growth, as represented by tree-ring chronologies (TRCs), runoff (Q), precipitation (P), and evapotranspiration (ET) are discussed within both statistical and hydrological contexts. The Oldman River Basin (OMRB), Alberta, Canada, is presented as a case study, with TRCs and hydrometeorological data used to demonstrate the relevant issues. Runoff and precipitation data were available through measurements, and actual evapotranspiration was estimated using a lumped conceptual hydrological model developed in this study for the OMRB. Correlation analysis was conducted to explore the relationships between TRCs and each of Q, P, and ET over the entire historical record (globally) as well as locally within the wet and dry subperiods. Global and local correlation strengths and linear relationships appear to be significantly different, particularly affecting tree-ring based inferences about the hydrology and wet and dry episodes from reconstructions made using regression models. This finding is not typically highlighted in the available literature. Reconstruction of paleoQ may also not be as credible as paleoP and paleoET. This is discussed within the context of the watershed storage and release functions. It was also found that a moving average window, of more than one year, of P and ET time series might be necessary for reconstruction of these variables using tree-ring chronologies. This study improves our understanding of

  10. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India.

    Science.gov (United States)

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Rajuru Ramakrishna, Reddy; Surendranair, Suresh Babu

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500nm are found to be 0.47±0.09, 0.34±0.08, 0.29±0.06 and 0.30±0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α380-1020) value is observed maximum in March (1.25±0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33±0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00-08:00 (IST) and evening 19:00-21:00 (IST) hours and one minima noticed during afternoon (13:00-16:00). The highest monthly mean BC concentration is observed in the month of January (3.4±1.2μgm(-3)) and the lowest in July (1.1±0.2μgm(-3)). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be +36.8±1.7Wm(-2), +26.9±0.2Wm(-2), +18.0±0.6Wm(-2) and +18.5±3.1Wm(-2) during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80Wm(-2)) which contributes more increase in atmospheric heating by ~1K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating. PMID:27344510

  11. Transport of multiple tracers in variably saturated humid region structured soils and semi-arid region laminated sediments

    Science.gov (United States)

    Mayes, M. A.; Jardine, P. M.; Mehlhorn, T. L.; Bjornstad, B. N.; Ladd, J. L.; Zachara, J. M.

    2003-05-01

    The processes governing physical nonequilibrium (PNE)—coupled preferential flow and matrix diffusion—are diverse between humid and semi-arid regions, and are directly related to climate and rock/sediment type, and indirectly related to subsequent soil profile development. The fate and transport of contaminants in these variably saturated undisturbed media is largely a function of the influence of PNE processes. Large cores of laminated silts and sands were collected from the US Department of Energy Pacific Northwest National Laboratory (PNNL) in semi-arid south central Washington. Additional cores of weathered, fractured interbedded limestone and shale saprolite were collected from the Oak Ridge National Laboratory (ORNL) in humid eastern Tennessee. PNNL cores were collected parallel (FBP) and perpendicular (FXB) to bedding, and the ORNL core was 30° to bedding. Saturated and unsaturated transport experiments were performed using multiple nonreactive tracers that had different diffusion coefficients (Br -, PFBA, and PIPES), in order to identify the influence of PNE on the fate and transport of solutes. In the ORNL structured saprolite, solute transport was governed by coupled preferential flow and matrix diffusion, as evidenced by tracer separation and highly asymmetric breakthrough curves (BTC). BTCs became more symmetric as preferential flowpaths became inactive during drainage. Tracer separation persisted during unsaturated flow suggesting the continued importance of nonequilibrium mass transfer between flowpaths and the immobile water that was held in the soil matrix. No evidence of PNE was observed under near-saturated conditions in the semi-arid region (PNNL) laminated silts and sands. Unsaturated flow in cores with discontinuous layering resulted in preferential flow and the development of perched, immobile water as evidenced by early breakthrough and separation of tracers. Conversely, transport parallel to laterally continuous beds did not result in

  12. a Proposed New Vegetation Index, the Total Ratio Vegetation Index (trvi), for Arid and Semi-Arid Regions

    Science.gov (United States)

    Fadaei, H.; Suzuki, R.; Sakai, T.; Torii, K.

    2012-07-01

    Vegetation indices that provide important key to predict amount vegetation in forest such as percentage vegetation cover, aboveground biomass, and leaf-area index. Arid and semi-arid areas are not exempt of this rule. Arid and semi-arid areas of northeast Iran cover about 3.4 million ha and are populated by two main tree species, the broadleaf Pistacia vera (pistachio) and the conifer Juniperus excelsa ssp. polycarpos (Persian juniper). Natural stands of pistachio in Iran are not only environmentally important but also genetically essential as seed sources for pistachio production in orchards. We investigated the relationships between tree density and vegetation indices in the arid and semi-arid regions in the northeast of Iran by analysing Advanced Land Observing Satellite (ALOS) data PRISM is a panchromatic radiometer with a 2.5 m spatial resolution at nadir, and has one band with a wavelength of 0.52-0.77 μm (JAXA EORC). AVNIR-2 is a visible and near infrared radiometer for observing land and coastal zones with a 10 m spatial resolution at nadir, and has four multispectral bands: blue (0.42-0.50 μm), green (0.52-0.60 μm), red (0.61-0.69 μm), and near infrared (0.76-0.89 μm) (JAXA EORC). In this study, we estimated various vegetation indices using maximum filtering algorithm (5×5) and examined. This study carried out of juniper forests and natural pistachio stand using Advanced Land Observing Satellite (ALOS) and field inventories. Have been compared linear regression model of vegetation indices and proposed new vegetation index for arid and semi-arid regions. Also, we estimated the densities of juniper forests and natural pistachio stands using remote sensing to help in the sustainable management and production of pistachio in Iran. We present a new vegetation index for arid and semi-arid regions with sparse forest cover, the Total Ratio Vegetation Index (TRVI), and we investigate the relationship of the new index to tree density by analysing data from the

  13. A PROPOSED NEW VEGETATION INDEX, THE TOTAL RATIO VEGETATION INDEX (TRVI, FOR ARID AND SEMI-ARID REGIONS

    Directory of Open Access Journals (Sweden)

    H. Fadaei

    2012-07-01

    Full Text Available Vegetation indices that provide important key to predict amount vegetation in forest such as percentage vegetation cover, aboveground biomass, and leaf-area index. Arid and semi-arid areas are not exempt of this rule. Arid and semi-arid areas of northeast Iran cover about 3.4 million ha and are populated by two main tree species, the broadleaf Pistacia vera (pistachio and the conifer Juniperus excelsa ssp. polycarpos (Persian juniper. Natural stands of pistachio in Iran are not only environmentally important but also genetically essential as seed sources for pistachio production in orchards. We investigated the relationships between tree density and vegetation indices in the arid and semi-arid regions in the northeast of Iran by analysing Advanced Land Observing Satellite (ALOS data PRISM is a panchromatic radiometer with a 2.5 m spatial resolution at nadir, and has one band with a wavelength of 0.52–0.77 μm (JAXA EORC. AVNIR-2 is a visible and near infrared radiometer for observing land and coastal zones with a 10 m spatial resolution at nadir, and has four multispectral bands: blue (0.42–0.50 μm, green (0.52–0.60 μm, red (0.61–0.69 μm, and near infrared (0.76–0.89 μm (JAXA EORC. In this study, we estimated various vegetation indices using maximum filtering algorithm (5×5 and examined. This study carried out of juniper forests and natural pistachio stand using Advanced Land Observing Satellite (ALOS and field inventories. Have been compared linear regression model of vegetation indices and proposed new vegetation index for arid and semi-arid regions. Also, we estimated the densities of juniper forests and natural pistachio stands using remote sensing to help in the sustainable management and production of pistachio in Iran. We present a new vegetation index for arid and semi-arid regions with sparse forest cover, the Total Ratio Vegetation Index (TRVI, and we investigate the relationship of the new index to tree density by

  14. Efficiency of water and fertilizer use in semi-arid regions

    International Nuclear Information System (INIS)

    The proceedings contain 14 papers considering problems on soil and soil water, irrigation, and the use of fertilizers in semi-arid zones. Research projects in these fields are discussed and results obtained so far are reported (tables and diagrams on the behaviour of water and fertilizers in soils). The use of radioisotope techniques is mentioned briefly. Finally, some future ''first priority'' research areas are identified and recommendations for further research programs are given. These programs aim at reducing the hazards of crop failure and at increasing production under dry farming conditions

  15. Modeling the Surface Water-Groundwater Interaction in Arid and Semi-Arid Regions Impacted by Agricultural Activities

    Science.gov (United States)

    Tian, Y.; Wu, B.; Zheng, Y.

    2013-12-01

    In many semi-arid and arid regions, interaction between surface water and groundwater plays an important role in the eco-hydrological system. The interaction is often complicated by agricultural activities such as surface water diversion, groundwater pumping, and irrigation. In existing surface water-groundwater integrated models, simulation of the interaction is often simplified, which could introduce significant simulation uncertainty under certain circumstance. In this study, GSFLOW, a USGS model coupling PRMS and MODFLOW, was improved to better characterize the surface water-groundwater interaction. The practices of water diversion from rivers, groundwater pumping and irrigation are explicitly simulated. In addition, the original kinematic wave routing method was replaced by a dynamic wave routing method. The improved model was then applied in Zhangye Basin (the midstream part of Heihe River Baisn), China, where the famous 'Silk Road' came through. It is a typical semi-arid region of the western China, with extensive agriculture in its oasis. The model was established and calibrated using the data in 2000-2008. A series of numerical experiments were conducted to evaluate the effect of those improvements. It has been demonstrated that with the improvements, the observed streamflow and groundwater level were better reproduced by the model. The improvements have a significant impact on the simulation of multiple fluxes associated with the interaction, such as groundwater discharge, riverbed seepage, infiltration, etc. Human activities were proved to be key elements of the water cycle in the study area. The study results have important implications to the water resources modeling and management in semi-arid and arid basins.

  16. Impacts of urbanization on nitrogen cycling and aerosol, surface and groundwater transport in semi-arid regions

    Science.gov (United States)

    Lohse, K. A.; Gallo, E.; Carlson, M.; Riha, K. M.; Brooks, P. D.; McIntosh, J. C.; Sorooshian, A.; Michalski, G. M.; Meixner, T.

    2011-12-01

    Semi-arid regions are experiencing disproportionate increases in human population and land transformation worldwide, taxing limited water resources and altering nitrogen (N) biogeochemistry. How the redistribution of water and N by urbanization affects semi-arid ecosystems and downstream water quality (e.g. drinking water) is unclear. Understanding these interactions and their feedbacks will be critical for developing science-based management strategies to sustain these limited resources. This is especially true in the US where some of the fastest growing urban areas are in semi-arid ecosystems, where N and water cycles are accelerated, and intimately coupled, and where runoff from urban ecosystems is actively managed to augment a limited water supply to the growing human population. Here we synthesize several ongoing studies from the Tucson Basin in Arizona and examine how increasing urban land cover is altering rainfall-runoff relationships, groundwater recharge, water quality, and long range transport of atmospheric N. Studies across 5 catchments varying in impervious land cover showed that only the least impervious catchment responded to antecedent moisture conditions while hydrologic responses were not statistically related to antecedent rainfall conditions at more impervious sites. Regression models indicated that rainfall depth, imperviousness, and their combined effect control discharge and runoff ratios (p < 0.01, r2 = 0.91 and 0.75, respectively). In contrast, runoff quality was not predictably related to imperviousness or catchment size. Rather, rainfall depth and duration, time since antecedent rainfall, and stream channel characteristics and infrastructure controlled runoff chemistry. Groundwater studies showed nonpoint source contamination of CFCs and associated nitrate in areas of rapid recharge along ephemeral channels. Aerosol measurements indicate that both long-range transport of N and N emissions from Tucson are being transported and deposited

  17. Different responses of MODIS-derived NDVI to root-zone soil moisture in semi-arid and humid regions

    Science.gov (United States)

    Wang, Xianwei; Xie, Hongjie; Guan, Huade; Zhou, Xiaobing

    2007-06-01

    SummarySurface representation of the root-zone soil moisture is investigated so that feasibility of using optical remote sensing techniques to indirectly map root-zone soil moisture is assessed. Specifically, covariation of root-zone soil moisture with the normalized difference of vegetation index (NDVI) from Moderate Resolution Imaging Spectroradiometer (MODIS) is studied at three sites (New Mexico, Arizona, and Texas) selected from the Soil Climate Analysis Network (SCAN). The three sites represent two types of vegetation (shrub and grass) and two types of climate conditions: semi-arid (New Mexico and Arizona) and humid (Texas). Collocated deseasonalized time series of soil moistures at five depths (5 cm, 10 cm, 20 cm, 50 cm, and 100 cm) and NDVI (8-day composite in 250 m resolution) during the period of February 2000 through April 2004 were used for correlation analysis. Similar analysis was also conducted for the raw time series for comparison purposes. The linear regression of both the deseasonalized time series and the raw time series was used to estimate root-zone soil moisture. Results show that (1) the deseasonalized time series results in consistent and significant correlation (0.46-0.55) between NDVI and root-zone soil moisture at the three sites; (2) vegetation (NDVI) at the humid site needs longer time (10 days) to respond to soil moisture change than that at the semi-arid sites (5 days or less); (3) the time-series of root-zone soil moisture estimated by a linear regression model based on deseasonalized time series accounts for 42-71% of the observed soil moisture variations for the three sites; and (4) in the semi-arid region, root-zone soil moisture of shrub-vegetated area can be better estimated using NDVI than that of grass-vegetated area.

  18. Diurnal regulation of photosynthesis in Jatropha curcas under drought during summer in a semi-arid region

    International Nuclear Information System (INIS)

    The diurnal photosynthetic responses to drought in Jatropha curcas have not been well assessed under field conditions in harsh semi-arid habitats. To illustrate this, diurnal changes in chlorophyll fluorescence and gas exchange rates were measured in field-grown Jatropha with or without a short (13 days) water recovery treatment under drought conditions during hot summer in a semi-arid. Sensitive stomatal closure coordinated with a drying atmosphere strictly limited a net CO2 assimilation rate with a predominant morning peak, eventually turning negative during the day. Even though the risk of excess excitation energy which potentially causes photodamage increased with the extremely low capacity for CO2 fixation, Jatropha preserved the integrity of PSII. Quantitative analysis of quenching partitioning revealed that regulated thermal energy dissipation accounted a large fraction of both instantaneous and daily absorbed energy by up to 80 and 72%, respectively, under the drought condition. Water recovery treatment more than doubled daily CO2 uptake via mitigating diurnal stomatal closure. The regulated thermal dissipation flexibly adjusted PSII quantum efficiency to capacity of CO2 fixation. In addition, downregulation of PSII quantum efficiency via sustained regulated thermal dissipation was observed and thought to be an additional photoprotective function. It is clear that Jatropha strongly rely upon the regulated thermal dissipation under drought condition, which must be critically important for this strict water conserving species, especially under a climate with high solar radiation loads as is seen in semi-arid regions. - Highlights: • Diurnal gas exchange and the fate of absorbed energy were assessed in Jatropha. • The dynamic stomatal closure was the predominant restriction under water stress. • The PSII integrity was preserved even under severe water stress. • The regulated thermal dissipation accounted by up to 72% of daily absorbed energy. • The

  19. Hierarchical distance-based fuzzy approach to evaluate urban water supply systems in a semi-arid region.

    Science.gov (United States)

    Yekta, Tahereh Sadeghi; Khazaei, Mohammad; Nabizadeh, Ramin; Mahvi, Amir Hossein; Nasseri, Simin; Yari, Ahmad Reza

    2015-01-01

    Hierarchical distance-based fuzzy multi-criteria group decision making was served as a tool to evaluate the drinking water supply systems of Qom, a semi-arid city located in central part of Iran. A list of aspects consisting of 6 criteria and 35 sub-criteria were evaluated based on a linguistic term set by five decision-makers. Four water supply alternatives including "Public desalinated distribution system", "PET Bottled Drinking Water", "Private desalinated water suppliers" and "Household desalinated water units" were assessed based on criteria and sub-criteria. Data were aggregated and normalized to apply Performance Ratings of Alternatives. Also, the Performance Ratings of Alternatives were aggregated again to achieve the Aggregate Performance Ratings. The weighted distances from ideal solution and anti-ideal solution were calculated after secondary normalization. The proximity of each alternative to the ideal solution was determined as the final step. The alternatives were ranked based on the magnitude of ideal solutions. Results showed that "Public desalinated distribution system" was the most appropriate alternative to supply the drinking needs of Qom population. Also, "PET Bottled Drinking Water" was the second acceptable option. A novel classification of alternatives to satisfy the drinking water requirements was proposed which is applicable for the other cities located in semi-arid regions of Iran. The health issues were considered as independent criterion, distinct from the environmental issues. The constraints of high-tech alternatives were also considered regarding to the level of dependency on overseas. PMID:26221535

  20. Hierarchical distance-based fuzzy approach to evaluate urban water supply systems in a semi-arid region.

    Science.gov (United States)

    Yekta, Tahereh Sadeghi; Khazaei, Mohammad; Nabizadeh, Ramin; Mahvi, Amir Hossein; Nasseri, Simin; Yari, Ahmad Reza

    2015-01-01

    Hierarchical distance-based fuzzy multi-criteria group decision making was served as a tool to evaluate the drinking water supply systems of Qom, a semi-arid city located in central part of Iran. A list of aspects consisting of 6 criteria and 35 sub-criteria were evaluated based on a linguistic term set by five decision-makers. Four water supply alternatives including "Public desalinated distribution system", "PET Bottled Drinking Water", "Private desalinated water suppliers" and "Household desalinated water units" were assessed based on criteria and sub-criteria. Data were aggregated and normalized to apply Performance Ratings of Alternatives. Also, the Performance Ratings of Alternatives were aggregated again to achieve the Aggregate Performance Ratings. The weighted distances from ideal solution and anti-ideal solution were calculated after secondary normalization. The proximity of each alternative to the ideal solution was determined as the final step. The alternatives were ranked based on the magnitude of ideal solutions. Results showed that "Public desalinated distribution system" was the most appropriate alternative to supply the drinking needs of Qom population. Also, "PET Bottled Drinking Water" was the second acceptable option. A novel classification of alternatives to satisfy the drinking water requirements was proposed which is applicable for the other cities located in semi-arid regions of Iran. The health issues were considered as independent criterion, distinct from the environmental issues. The constraints of high-tech alternatives were also considered regarding to the level of dependency on overseas.

  1. Resistência natural de nove madeiras do semiárido brasileiro a fungos xilófagos em simulares de campo Natural resistance of nine woods from the Brazilian semi-arid region to wood-destroying fungi in field simulators

    Directory of Open Access Journals (Sweden)

    Juarez Benigno Paes

    2009-06-01

    Full Text Available Os objetivos desta pesquisa foram avaliar a resistência de nove madeiras de ocorrência no semiárido brasileiro a fungos xilófagos em simuladores de campo e relacionar a resistência natural com a densidade e teor de substâncias extraídas em água quente. As madeiras estudadas foram algaroba (Prosopis juliflora, angico-vermelho (Anadenanthera colubrina var. cebil, aroeira (Myracrodruon urundeuva, braúna (Schinopsis brasiliensis, cássia (Senna siamea, craibeira (Tabebuia aurea, cumaru (Amburana cearensis, pau-d'arco (Tabebuia impetiginosa e pereiro (Aspidosperma pyrifolium. De cada espécie foram retirados corpos-de-prova de 0,5 x 1,5 x 15,0 cm, com a maior dimensão na direção das fibras, em quatro posições na direção medula-casca do tronco. As amostras permaneceram por 180 dias sob ação da microflora natural existente em três tipos de solos: de floresta, de uso agrícola e com gramíneas. Em todas as madeiras ensaiadas, a resistência ao apodrecimento foi afetada pela posição na direção medula-casca. Apenas na aroeira a resistência da madeira esteve associada à sua densidade e à quantidade de extrativos solúveis em água quente. A resistência das madeiras de algaroba, angico, craibeira e pau-d'arco não esteve associada à densidade nem ao teor de extrativos. O alburno foi a posição mais atacada em todos os solos analisados. Entre os solos testados, o de uso agrícola apresentou menos atividade biológica, deteriorando menos as madeiras testadas.The objectives of this research were to evaluate the natural resistance of nine woods from the Brazilian semi-arid region to fungi under field simulator condition and to correlate the wood natural resistance with the wood density and the content of extractives soluble in hot water. The studied woods were Prosopis juliflora, Anadenanthera colubrina var. cebil, Myracrodruon urundeuva, Schinopsis brasiliensis, Senna siamea, Tabebuia aurea, Amburana cearensis, Tabebuia

  2. Regional validity of the parameters of a distributed runoff-erosion model in the semi-arid region of Brazil

    Institute of Scientific and Technical Information of China (English)

    SRINIVASAN; Vajapeyam; Srirangachar; PAIVA; Fernanda; Maria; de; Lima

    2009-01-01

    The present paper examines the validity of the application of a distributed rainfall-runoff-erosion model on a regional basis in a semi-arid region of Brazil. The model tested is known as WESP (Water Erosion Simulation Program) developed by Lopes (1987). The model simulates the hydrograph and the sediment graph for individual events and thus, the model when properly calibrated can serve as a predictive tool for runoff and soil erosion on an individual or a continuous basis. The possibility of the existence of regionally applicable values for the parameters of the model WESP would be very interesting from the point of view of predictability of runoff and soil erosion from ungauged basins in the region. For this purpose, data collected in several experimental units in the experimental basin of Sumé as well as in the experimental basin of So Joo de Cariri have been used. The model was calibrated and validated in each of the experimental units (consisting of erosion plots and micro-basins) and the average value from all of the units for each of the parameters was considered to be the regional value. With these average values, all the events in all the experimental units were simulated. The results show that the runoff and erosion values simulated with this single parameter set were very good in all the units, being well within the acceptable deviations.

  3. Regional validity of the parameters of a distributed runoff-erosion model in the semi-arid region of Brazil

    Institute of Scientific and Technical Information of China (English)

    SRINIVASAN Vajapeyam Srirangachar; PAIVA Fernanda Maria de Lima

    2009-01-01

    The present paper examines the validity of the application of a distributed rainfall-runoff-erosion model on a regional basis in a semi-arid region of Brazil.The model tested is known as WESP (Water Erosion Simulation Program) developed by Lopes (1987).The model simulates the hydrograph and the sedi-ment graph for individual events and thus, the model when properly calibrated can serve as a predic-tive tool for runoff and soil erosion on an individual or a continuous basis.The possibility of the exis-tence of regionally applicable values for the parameters of the model WESP would be very interesting from the point of view of predictability of runoff and soil erosion from ungauged basins in the region.For this purpose, data collected in several experimental units in the experimental basin of Sume as well as in the experimental basin of Sao Joao de Cariri have been used.The model was calibrated and validated in each of the experimental units (consisting of erosion plots and micro-basins) and the av-erage value from all of the units for each of the parameters was considered to be the regional value.With these average values, all the events in all the experimental units were simulated.The results show that the runoff and erosion values simulated with this single parameter set were very good in all the units, being well within the acceptable deviations.

  4. Satellite-Based Monitoring of Decadal Soil Salinization and Climate Effects in a Semi-arid Region of China

    Institute of Scientific and Technical Information of China (English)

    WANG Hesong; JIA Gensuo

    2012-01-01

    Soil salinization is a common phenomenon that affects both the environment and the socio-economy in arid and semi-arid regions; it is also an important aspect of land cover change.In this study,we integrated multi-sensor remote sensing data with a field survey to analyze processes of soil salinization in a semi-arid area in China from 1979 to 2009. Generally,the area of salt-affected soils increased by 0.28% per year with remarkable acceleration from 1999 to 2009 (0.42% increase per year).In contrast,the area of surface water bodies showed a decreasing trend (-0.08% per year) in the same period.Decreases in precipitation and increases in aridity due to annual (especially summer) warming provided a favorable condition for soil salinization. The relatively flat terrain favored waterlogging at the surface,and continuous drought facilitated upward movement of soil water and accumulation of surface saline and calcium. Meanwhile,land-use practices also played a crucial role in accelerating soil salinization.The conversion to cropland from natural vegetation greatly increased the demand for groundwater irrigation and aggravated the process of soil salinization.Furthermore,there are potential feedbacks of soil salinization to regional climate.The salinization of soils can limit the efficiency of plant water use as well as photosynthesis; therefore,it reduces the amount of carbon sequestrated by terrestrial ecosystem.Soil salinization also reduces the absorbed solar radiation by increasing land surface albedo.Such conversions of land cover significantly change the energy and water balance between land and atmosphere.

  5. Helminth parasites and reservoir status of captive wild ruminants in the semi-arid region of north-eastern Nigeria.

    Directory of Open Access Journals (Sweden)

    Umar I Ibrahim

    Full Text Available Aim: To determine the various helminth parasites and associated helminth reservoir status of captive wild ruminants in the semi-arid region of north-eastern, Nigeria. Materials and Methods: Faecal samples were examined for nematode ova by the simple floatation technique using saturated sodium chloride solution as floatation medium. Trematode eggs were examined by the sedementation technique. The modified McMaster technique was used to determine the intensity of helminth infections among the various species of wild ruminants examined, while larval isolation and identification using the modified Baerman’s technique was used to determine the various species of parasites encountered. Results: Out of the 36 samples examined, a high parasite count due to Strongyle infection without the manifestation of overt clinical signs was observed among the captive wild ruminants. The egg counts ranged from 500 + 10.0 among the Grimm’s duicker (Sylvicaprea grimmia to 5, 350 + 51.70 among the Senegal hartebeest (Damaliscus korrigum. The helminth larvae recovered which were common to all the species of wild ruminants were those of Haemonchus contortus, Trichostrogylus axei and Strongyloides papillosus, Demographic data such as age, sex and species of wild animals showed no significant (p>0.05 variation on the prevalence of the helminth infections. Conclusion: The results of this study suggests that the captive wild ruminants in the semi-arid region of north-eastern, Nigeria, were reservoirs of various helminth parasites of medical and veterinary importance. It was therefore, recommended that improved sanitary conditions in animal enclosures, regular and strategic anthelmintic medications may on one hand protect the spread of infection to attendants and visitors to the park. On the other hand it will enhance the in-situ conservation of the rare and endangered species of wild ruminants in the area. [Vet World 2012; 5(9.000: 530-534

  6. A review of groundwater recharge estimation in humid and semi-arid African regions

    Science.gov (United States)

    Chung, Il-Moon; Kim, Nam Won

    2016-04-01

    For the review of African recharge estimation, the distinct methods such as the geochemical approach, a method using groundwater level data, the streamflow method, and the water balance methods were first outlined. The major challenge of an African recharge study is the lack of basic data. Thus, this work suggests how to deal with this limitation and from future perspective using recently developed technologies such as RS, GIS, etc. With the rapid growth of information technology, more and more data, in terms of both volume and variety, are expected to be made available on the internet in the near future. RS technology has a great potential to revolutionize the groundwater development and management in the future by providing unique and completely new hydrological and hydrogeological data. However, at present, the RS data should be considered along with the conventional field data. In spite of the weaknesses of water balance methods in semi-arid areas, recently developed water balance methods combined with GIS technology are powerful tools for estimating groundwater re-charge, when spatial-temporal variability of components in water balance is taken into account (Lerner et al., 1990; De Vries and Simmers, 2002; Eilers et al., 2007).When enough data sets are available, integrated surface-groundwater modeling is recommended for more accurate estimation of groundwater recharge and discharge. Acknowledgements This work was supported by a grant(14RDRP-B076275-01-000000) from Infrastructure and transportation technology promotion research Program funded by the Ministry of Land, Infrastructure and Transport of Korean government.

  7. Linking Bayesian and agent-based models to simulate complex social-ecological systems in semi-arid regions

    Directory of Open Access Journals (Sweden)

    Aloah J Pope

    2015-08-01

    Full Text Available Interdependencies of ecologic, hydrologic, and social systems challenge traditional approaches to natural resource management in semi-arid regions. As a complex social-ecological system, water demands in the Sonoran Desert from agricultural and urban users often conflicts with water needs for its ecologically-significant riparian corridors. To explore this system, we developed an agent-based model to simulate complex feedbacks between human decisions and environmental conditions in the Rio Sonora Watershed. Cognitive mapping in conjunction with stakeholder participation produced a Bayesian model of conditional probabilities of local human decision-making processes resulting to changes in water demand. Probabilities created in the Bayesian model were incorporated into the agent-based model, so that each agent had a unique probability to make a positive decision based on its perceived environment at each point in time and space. By using a Bayesian approach, uncertainty in the human decision-making process could be incorporated. The spatially-explicit agent-based model simulated changes in depth-to-groundwater by well pumping based on an agent’s water demand. Changes in depth-to-groundwater feedback to influence agent behavior, as well as determine unique vegetation classes within the riparian corridor. Each vegetation class then provides varying stakeholder-defined quality values of ecosystem services. Using this modeling approach allowed us to examine effects on both the ecological and social system of semi-arid riparian corridors under various scenarios. The insight provided by the model contributes to understanding how specific interventions may alter the complex social-ecological system in the future.

  8. MACROINVERTEBRATE SAMPLING TECHNIQUES FOR STREAMS IN SEMI-ARID REGIONS. COMPARISON OF THE SURBER METHOD AND A UNIT-EFFORT TRAVELING KICK METHOD

    Science.gov (United States)

    Streams of the arid and semi-arid regions of the western United States are characterized by irregular flow patterns resulting in highly unstable macroinvertebrate habitats and a sparse macrobenthic fauna. The use of a standard square-foot Surber stream-bottom sampler is of limite...

  9. Aerosol radiative effects over global arid and semi-arid regions based on MODIS Deep Blue satellite observations

    Science.gov (United States)

    Hatzianastassiou, Nikolaos; Papadimas, Christos D.; Gkikas, Antonis; Matsoukas, Christos; Sayer, Andrew M.; Hsu, N. Christina; Vardavas, Ilias

    2014-05-01

    Aerosols are a key parameter for several atmospheric processes related to weather and climate of our planet. Specifically, the aerosol impact on Earth's climate is exerted and quantified through their radiative effects, which are induced by their direct, indirect and semi-direct interactions with radiation, in particular at short wavelengths (solar). It is acknowledged that the uncertainty of present and future climate assessments is mainly associated with aerosols and that a better understanding of their physico-chemical, optical and radiative effects is needed. The contribution of satellites to this aim is important as a complementary tool to climate and radiative transfer models, as well as to surface measurements, since space observations of aerosol properties offer an extended spatial coverage. However, such satellite based aerosol properties and associated model radiation computations have suffered from unavailability over highly reflecting surfaces, namely polar and desert areas. This is also the case for MODIS which, onboard the Terra and Aqua satellites, has been providing high quality aerosol data since 2000 and 2002, respectively. These data, more specifically the aerosol optical depth (AOD) which is the most important optical property used in radiative and climate models, are considered to be of best quality. In order to address this problem, the MODIS Deep Blue (DB) algorithm has been developed which enables the retrieval of AOD above arid and semi-arid areas of the globe, including the major deserts. In the present study we make use of the FORTH detailed spectral radiative transfer model (RTM) with MODIS DB AOD data, supplemented with single scattering albedo (SSA) and asymmetry parameter (AP) aerosol data from the Global Aerosol DataSet (GADS) to estimate the aerosol DREs over the arid and semi-arid regions of the globe. The RTM is run using surface and atmospheric data from the ISCCP-D2 dataset and the NCEP global reanalysis project and computes the

  10. Simulated biomass, environmental impacts and best management practices for long-term switchgrass systems in a semi-arid region

    International Nuclear Information System (INIS)

    Long-term information on switchgrass (Panicum virgatum L.) as a biomass energy crop grown on marginally saline soil and the associated impacts on soil carbon (C) and nitrogen (N) dynamics, greenhouse gas (GHG) emissions, and best management practices (BMPs) are limited. In this study, we employed the DAYCENT model, based on a 4-year switchgrass field experiment, to evaluate the long-term biomass yield potential and environmental impacts, and further to develop BMPs for switchgrass in a semi-arid region. The model showed that long-term (14-year) annual mean biomass yields were 9.6 and 5.2 Mg ha−1 for irrigated and rainfed switchgrass systems, respectively. The simulated biomass yields correlated well with field-measured biomass with r2 values of 0.99 and 0.89 for irrigated and rainfed systems, respectively. Soil organic carbon (SOC) and soil total nitrogen (STN) accumulated rapidly after switchgrass establishment, with mean accrual rates of 0.99–1.13 Mg C ha−1 yr−1 and 0.04–0.08 Mg N ha−1 yr−1, respectively. Based on the outputs of numerous long-term model simulations with variable irrigation water supplies and N rates, the irrigation regime and N rate with the highest yield to input ratio were chosen as BMPs. The DAYCENT model predicted-BMP was irrigating every 14 days at 70% potential evapotranspiration combined with an N rate of 67 kg ha−1 yr−1. Switchgrass established and produced biomass reasonably well in this semi-arid region; however, appropriate irrigation and N fertilization were needed for optimal biomass yield. Switchgrass had a great potential to sequester C into soils with low N2O emissions while supplying significant quantities of biomass for biofuel synthesis. - Highlights: • The DAYCENT model reliably simulated the growth of switchgrass on marginal land. • Long-term biomass and environmental impacts were simulated using the DAYCENT model. • Switchgrass produced biomass well on marginal land, but irrigation and

  11. Remote Sensing Based Analysis of Recent Variations in Water Resources and Vegetation of a Semi-Arid Region

    Directory of Open Access Journals (Sweden)

    Shaowei Ning

    2015-11-01

    Full Text Available This study is designed to demonstrate use of free remote sensing data to analyze response of water resources and grassland vegetation to a climate change induced prolonged drought in a sparsely gauged semi-arid region. Water resource changes over Hulun Lake region derived from monthly Gravity Recovery and Climate Experiment (GRACE and Tropical Rainfall Measuring Mission (TRMM products were analyzed. The Empirical Orthogonal Functions (EOF analysis results from both GRACE and TRMM showed decreasing trends in water storage changes and precipitation over 2002 to 2007 and increasing trends after 2007 to 2012. Water storage and precipitation changes on the spatial and temporal scale showed a very consistent pattern. Further analysis proved that water storage changes were mainly caused by precipitation and temperature changes in this region. It is found that a large proportion of grassland vegetation recovered to its normal state after above average rainfall in the following years (2008–2012 and only a small proportion of grassland vegetation (16.5% of the study area is degraded and failed to recover. These degraded grassland vegetation areas are categorized as ecologically vulnerable to climate change and protective strategies should be designed to prevent its further degradation.

  12. A Reservoir of Natural Perchlorate in Unsaturated Zones of Arid and Semi-Arid Regions, Southwestern USA

    Science.gov (United States)

    Rao, B. A.; Stonestrom, D. A.; Anderson, T. A.; Orris, G. J.; Rajagapolan, S.; Sandvig, R. M.; Scanlon, B. R.; Walvoord, M. A.; Jackson, W.

    2006-12-01

    Natural perchlorate (ClO4-) is generally present in unsaturated zones of steppe-to-desert regions of the arid and semi-arid southwestern United States. The perchlorate is associated with atmospherically deposited chloride that has accumulated throughout the Holocene. To assess this natural reservoir, we analyzed unsaturated-zone profiles from ten sites across Nevada, New Mexico, Texas, and Utah for perchlorate and other anions. The sampled sites represent a wide range of precipitation (0.1 0.5 m yr-1), dominant vegetation, soil type, underlying geology, and include five distinct ecological regions: Chihuahuan, Mojave, and southern Great Basin deserts; Arizona-New Mexico semi-desert; and Texas High Plains dry steppe. Concentrations of perchlorate correlated closely with chloride and bromide. The perchlorate reservoir (up to 1 kg ha-1) is sufficiently large to impact groundwater when natural recharge during pluvial periods or induced recharge after conversion to agriculture flushes accumulated salts from the unsaturated zone. This little explored source can explain perchlorate in milk and other agricultural products far from anthropogenic contamination, and should be considered when evaluating overall exposure risk.

  13. Assessment of Groundwater Chemistry and Status in a Heavily Used Semi-Arid Region with Multivariate Statistical Analysis

    Directory of Open Access Journals (Sweden)

    Xuedi Zhang

    2014-07-01

    Full Text Available This hydrogeological study assessed the quality of phreatic water supplies across the semi-arid, traditional agricultural region of the Yinchuan region in northwest China, near the upper reaches of the Yellow River. We analyzed the chemical characteristics of water collected from 39 sampling stations before the 2011 summer-autumn irrigation period, using multivariate statistical analysis and geostatistical methods. We determined which factors influence the composition of groundwater, using principal component analysis (PCA and two modes of cluster analysis. PCA showed that the most important variables in the study area were the strong evaporation effect caused by the dry climate, dissolution of carbonate minerals and those containing F− and K−, and human activity including the treatment of domestic sewage and chemical fertilization. The Q-mode of cluster analysis identified three distinct water types that were distinguished by different chemical compositions, while the R-mode of analysis revealed two distinct clusters of sampling stations that appeared to be influenced by distinct sets of natural and/or anthropogenic factors.

  14. Soil surface moisture estimation over a semi-arid region using ENVISAT ASAR radar data for soil evaporation evaluation

    Directory of Open Access Journals (Sweden)

    M. Zribi

    2011-01-01

    Full Text Available The present paper proposes a method for the evaluation of soil evaporation, using soil moisture estimations based on radar satellite measurements. We present firstly an approach for the estimation and monitoring of soil moisture in a semi-arid region in North Africa, using ENVISAT ASAR images, over two types of vegetation covers. The first mapping process is dedicated solely to the monitoring of moisture variability related to rainfall events, over areas in the "non-irrigated olive tree" class of land use. The developed approach is based on a simple linear relationship between soil moisture and the backscattered radar signal normalised at a reference incidence angle. The second process is proposed over wheat fields, using an analysis of moisture variability due to both rainfall and irrigation. A semi-empirical model, based on the water-cloud model for vegetation correction, is used to retrieve soil moisture from the radar signal. Moisture mapping is carried out over wheat fields, showing high variability between irrigated and non-irrigated wheat covers. This analysis is based on a large database, including both ENVISAT ASAR and simultaneously acquired ground-truth measurements (moisture, vegetation, roughness, during the 2008–2009 vegetation cycle. Finally, a semi-empirical approach is proposed in order to relate surface moisture to the difference between soil evaporation and the climate demand, as defined by the potential evaporation. Mapping of the soil evaporation is proposed.

  15. Dimethylamine as a major alkyl amine species in particles and cloud water: Observations in semi-arid and coastal regions

    Science.gov (United States)

    Youn, J.-S.; Crosbie, E.; Maudlin, L. C.; Wang, Z.; Sorooshian, A.

    2015-12-01

    Aerosol and cloud water measurements of dimethylamine (DMA), the most abundant amine in this study, were conducted in semi-arid (Tucson, Arizona) and marine (Nucleation in California Experiment, NiCE; central coast of California) areas. In both regions, DMA exhibits a unimodal aerosol mass size distribution with a dominant peak between 0.18 and 0.56 μm. Particulate DMA concentrations increase as a function of marine biogenic emissions, sulfate, BVOC emissions, and aerosol-phase water. Such data supports biogenic sources of DMA, aminium salt formation, and partitioning of DMA to condensed phases. DMA concentrations exhibit positive correlations with various trace elements and most especially vanadium, which warrants additional investigation. Cloud water DMA levels are enhanced significantly during wildfire periods unlike particulate DMA levels, including in droplet residual particles, due to effective dissolution of DMA into cloud water and probably DMA volatilization after drop evaporation. DMA:NH4+ molar ratios peak between 0.18 and 1.0 μm depending on the site and time of year, suggesting that DMA competes better with NH3 in those sizes in terms of reactive uptake by particles.

  16. Maximizing biomass production in semi-arid regions: genotypic selection of identified species. [Saltbush and Johnson Grass

    Energy Technology Data Exchange (ETDEWEB)

    Goodin, J.R.; Newton, R.J.

    1983-08-31

    This project identifies genotypes selected from two species of unconventional plants previously identified as having exceptional potential for the production of biomass feedstock in semi-arid regions. The project involved collection of germ plasm from indigenous Atriplex canescens (saltbush) and introduced Sorghum halepense (Johnson grass). In addition, greenhouse and field screening techniques recently aplied to domesticated crop plants are used to identify exceptional biomass productivity based on drought tolerance, salinity tolerance, and seedling vigor. In both of these species, the genetic base is enormous. Saltbush is common to all of western North America, and Johnsongrass had established itself as an important forage and weedy species throughout most of the world. It would appear that artificial selection for desirable genotypes is a feasible process, and this project has demonstrated the possibility of selection from many accessions from the field. Preliminary screening for seedling vigor, drought tolerance, and salt tolerance has produced a few genotypes now ready for field testing. Propagation of these cloned genotypes is underway. 22 references, 2 figures, 1 table.

  17. Effects of adding water on seasonal variation of soil nitrogen availability under sandy grasslands in semi-arid region

    Institute of Scientific and Technical Information of China (English)

    HUANG Xiao-xing; YU Zhan-yuan; QIAN Wei; XU Da-yong; AI Gui-yan

    2007-01-01

    Water is usally thought of a limiting factor for the restoration of semi-arid ecosystem. In the growing season of 2006, a study was conducted to determine the effects of modeling precipitation on seasonal patterns in concentrations of soil-available nitrogen and to describe the seasonal patterns in soil nitrogen availability and seasonal variation in the rates of net nitrogen mineralization of topsoil at Daqinggou ecological station in Keerqin sand lands, Inner Mongolia Autonomous Region, China. Manipulation of water (80 mm) was designed to be added to experiment plots of sandy grasslands in dry season. Water addition (W) treatment and control (CK) treatment were separately taken in six replications and randomly assigned in 12 plots (4 m×4 m for each) with 2-m buffers betweens. Results showed that the content of soil inorganic nitrogen and net nitrogen mineralization rate were not affected by adding water in sandy grassland of Keerqin sand lands. Net nitrogen mineralization rates ranged from 0.5 μg·g-1·month-1 to 4 μg·g-1·month-1. The highest values of soil inorganic nitrogen and net nitrogen mineralization occurred on October 15 in control plots. The seasonal changes of soil inorganic nitrogen contents exhibited "V" shape pattern that was related to seasonal patterns of soil ammonium-N (ascending trend) and nitrate-N transformation (descending trend).

  18. A PROPOSED NEW VEGETATION INDEX, THE TOTAL RATIO VEGETATION INDEX (TRVI), FOR ARID AND SEMI-ARID REGIONS

    OpenAIRE

    H. Fadaei; Suzuki, R.; Sakai, T; Torii, K.

    2012-01-01

    Vegetation indices that provide important key to predict amount vegetation in forest such as percentage vegetation cover, aboveground biomass, and leaf-area index. Arid and semi-arid areas are not exempt of this rule. Arid and semi-arid areas of northeast Iran cover about 3.4 million ha and are populated by two main tree species, the broadleaf Pistacia vera (pistachio) and the conifer Juniperus excelsa ssp. polycarpos (Persian juniper). Natural stands of pistachio in Iran are not only environ...

  19. Applicability of the Thermal Infrared Spectral Region for the Prediction of Soil Properties Across Semi-Arid Agricultural Landscapes

    Directory of Open Access Journals (Sweden)

    Sabine Chabrillat

    2012-10-01

    Full Text Available In this study we tested the feasibility of the thermal infrared (TIR wavelength region (within the atmospheric window between 8 and 11.5 μm together with the traditional solar reflective wavelengths for quantifying soil properties for coarse-textured soils from the Australian wheat belt region. These soils have very narrow ranges of texture and organic carbon contents. Soil surface spectral signatures were acquired in the laboratory, using a directional emissivity spectrometer (μFTIR in the TIR, as well as a bidirectional reflectance spectrometer (ASD FieldSpec for the solar reflective wavelengths (0.4–2.5 μm. Soil properties were predicted using multivariate analysis techniques (partial least square regression. The spectra were resampled to operational imaging spectroscopy sensor characteristics (HyMAP and TASI-600. To assess the relevance of specific wavelength regions in the prediction, the drivers of the PLS models were interpreted with respect to the spectral characteristics of the soils’ chemical and physical composition. The study revealed the potential of the TIR (for clay: R2 = 0.93, RMSEP = 0.66% and for sand: R2 = 0.93, RMSEP = 0.82% and its combination with the solar reflective region (for organic carbon: R2 = 0.95, RMSEP = 0.04% for retrieving soil properties in typical soils of semi-arid regions. The models’ drivers confirmed the opto-physical base of most of the soils’ constituents (clay minerals, silicates, iron oxides, and emphasizes the TIR’s advantage for soils with compositions dominated by quartz and kaolinite.

  20. Establishment of a planted field with Mediterranean shrubs in Sardinia and its evaluation for climate mitigation and to combat desertification in semi-arid regions

    OpenAIRE

    De Dato GD; Loperfido L; De Angelis P; Valentini R

    2009-01-01

    Forested areas are important in arid and semi-arid regions primarily to combat desertification, but also to increase carbon sinks. To reverse the land degradation processes, restoration in the Mediterranean Basin had been frequently obtained by planting indigenous and exotic conifers, but it has been demonstrated that shrubs are nurse species for tree seedlings. Furthermore, planting indigenous shrubs is more efficient than allochthonous in restoring degraded soils. The aims of this work were...

  1. Seroprevalence of peste des petits ruminants among domestic small and large ruminants in the semi-arid region of North-eastern Nigeria

    OpenAIRE

    Abdul-Dahiru El-Yuguda; Saka Saheed Baba; Abdul Ganiyu Ambali; Godon O Egwu

    2013-01-01

    Background: Recent changes in the host range of peste des petits ruminants (PPR) virus coupled with the presence of a hugeruminant population in the study area has stimulated our interest to carry out a sero-survey for PPR among the differentdomestic ruminant populations of semi-arid region of North-eastern (NE) Nigeria.Materials and Methods: The prevalence of PPR virus antibodies among domestic animals (goat, sheep, cattle and camel)populations in NE Nigeria was studied using virus neutralis...

  2. Validation of MODIS and Deep Blue aerosol optical depth retrievals in an arid/semi-arid region of northwest China

    Institute of Scientific and Technical Information of China (English)

    Xia Li; Xiangao Xia; Shengli Wang; Jietai Mao; Yan Liu

    2012-01-01

    The global aerosol optical depth (AOD or τ) has been retrieved using the Dark Target algorithm (the C004 and C005 products) and the Deep Blue algorithm (DB product).Few validations have thus far been performed in arid/semi-arid regions,especially in northwest China.The ground-based remote sensing of AOD from sun photometers at four sites in Xinjiang during the years 2002-2003 is used to validate aerosol products,including C004,C005 and DB of the Moderate Resolution Imaging Spectroradiometer (MODIS).The results show substantial improvement in the C005 aerosol product over the C004 product.The average correlation coefficient of regression with ground measurements increased from 0.59 to 0.69,and the average offset decreased from 0.28 to 0.13.The slopes of the linear regressions tended to be close to unity.The percentage of AODs falling within the retrieval errors of 30% (or △τ =±0.1 ± 0.2τ)increased from 16.1% to 45.6%.The best retrievals are obtained over an oasis region,whereas the worst are obtained over urban areas.Both the MODIS C004 and C005 products overestimate AOD,which is likely related to improper assumptions of the aerosol model and of the estimation of surface reflectance.An encouraging result has been derived with regard to validation of the DB AOD.Overall,the average offset,slope and correlation coefficient of regression with sun-photometer measurements are -0.04,0.88 and 0.85,respectively.Approximately 73% of the DB AOD retrievals fall within the expected error of 30%.Underestimation of the AOD by the DB products is observed.The aerosol model and estimations of surface reflectance in this region require further improvements.

  3. The International Workshop on Environmental Changes and Sustainable Development in Arid and Semi-arid Regions

    Institute of Scientific and Technical Information of China (English)

    Xiaoping Yang; Arthur Conacher

    2007-01-01

    @@ Arid regions,dominated by deserts,are characterized by a severe shortage of moisture,and a lack of perennial and integrated systems of drainage.Distributed over a very large range of temperatures,from the very hot to the very cold zones,arid regions cover about one third of the world's land surface and occur in every continent,including Antarctica.

  4. Plant species diversity of wetland ecosystem in an arid and semi-arid region in northwest China

    Institute of Scientific and Technical Information of China (English)

    LI Rui; LIU Yunfang; ZHANG Kebin

    2007-01-01

    In order to study the changes of plant species diversity along the biotope gradient and its influencing factors in a wetland-add grassland ecosystem in the add and semi-arid regions of northwest China,four transect lines were set along the biotope gradient in four directions:east,northeast,west and northwest,and altogether 123 sample plots were investigated on species composition,density,foliage cover,height and biomass (calculated in fresh weight).The whole study area was divided into the Wetland zone,the ecotone and the arid grassland zone in terms of habitat characteristics and vegetation types.In this paper,we analyzed and compared the species diversity in the ecotone of a wetland-dry grassland ecosystem in Yanchi County,Ningxia Hui Autonomous Region,with the help of biodiversity software BioDiversity Pro and statistical software Microcal Origin,as well as the combined measurement of species diversity indices.The results revealed distinct differences between those three vegetation zones along each transect line.The ecotone had the highest richness indices (R) and comprehensive diversity indices (Y),reflecting the edge effect.The greatest evenness indices (E) were found in the add grassland zones.This result agreed with the phenomenon of desertification reversion,vegetation restoration and dominant communities' formation.As for the four transect lines,the east and the northeast scored higher in each diversity index than the others due to less human disturbance,gentler topography uplift and more intercepted materials and energies.The highest Simpson index value was found in the northeast transect line,which was 39.9% higher than the lowest in the Northwest.

  5. Large scale characterization of unsaturated soil properties in a semi-arid region combining infiltration, pedotransfer functions and evaporation tests

    Science.gov (United States)

    Shabou, Marouen; Angulo-Jaramillo, Rafael; Lassabatère, Laurent; Boulet, Gilles; Mougenot, Bernard; Lili Chabaane, Zohra; Zribi, Mehrez

    2016-04-01

    Water resource management is a major issue in semi-arid regions, especially where irrigated agriculture is dominant on soils with highly variable clay content. Indeed, topsoil clay content has a significant importance on infiltration and evaporation processes and therefore in the estimation of the volume of water needed for crops. In this poster we present several methods to estimate wilting point, field capacity volumetric water contents and saturated hydraulic conductivity of the Kairouan plain (680 km2), central Tunisia (North Africa). The first method relies on the Beerkan Estimation of Soil Transfer parameters (BEST) method, which consists in local estimate of unsaturated soil hydraulic properties from a single-ring infiltration test, combined with the use of pedotransfer functions applied to the Kairouan plain different soil types. Results are obtained over six different topsoil texture classes along the Kairouan plain. Saturated hydraulic conductivity is high for coarse textured and some of the fine textured soils due to shrinkage cracking-macropore soil structure. The saturated hydraulic conductivity values are respectively 1.31E-5 m.s-1 and 1.71E-05 m.s-1. The second method is based on evaporation tests on different test plots. It consists of analyzing soil moisture profile changes during the dry down periods to detect the time-to-stress that can be obtained from observation of soil moisture variation, albedo measurements and variation of soil temperature. Results show that the estimated parameters with the evaporation method are close to those obtained by combining the BEST method and pedotransfer functions. The results validate that combining local infiltration tests and pedotransfer functions is a promising tool for the large scale hydraulic characterization of region with strong spatial variability of soils properties.

  6. Hunting strategies used in the semi-arid region of northeastern Brazil

    OpenAIRE

    Lopez Luiz CS; Vieira Washington LS; Confessor Maine VA; Mendonça Lívia ET; Alves Rômulo RN

    2009-01-01

    Abstract Hunting for wild animals is stimulated by the many different human uses of faunal resources, and these animals constitute important subsistence items in local communities in the Caatinga region. In order to gain access to these resources, hunters have developed a series of techniques and strategies that are described in the present work. The principal hunting techniques encountered were: waiting, especially directed towards hunting diurnal birds; calling ("arremedo"), a technique in ...

  7. Spatial pattern of a plant community in a wetland ecosystem in a semi-arid region in northwestern China

    Institute of Scientific and Technical Information of China (English)

    Kebin ZHANG; Rui LI; Yunfang LIU; Baitian WANG; Xiaohui YANG; Ruiping HOU

    2008-01-01

    The spatial distribution characteristics of plant communities in a wetland-dry grassland ecosystem in arid and semi-arid regions in northwestern China and the main factors affecting the distribution pattern were studied. The Siertan wetland in the Haba Lake Nature Reserve was the study area. Four transect lines, each about 1 km long, were set up in the growing season along the biotope gradient in four directions: east, northeast, west and northwest. Attributes measured include frequency of occurrence, height, density, coverage, biomass and envir-onmental soil factors. The data were analyzed using a two-way indicative species analysis (TWINSPAN), detrended correspondence analysis (DCA) and Spear-man correlation coefficients. On this basis, the vegetation in the Siertan wetland was classified into three types and 14 associations. The first vegetation type was halophytic marsh vegetation, mainly distributed in the wetland zone. This type largely contains halophyte and hygric plants and its representative association is Phragmites communis + Kalidiumfoliatum. The second type was meadow vegeta-tion, distributed in the ecotone. The meadow vegetation species are mainly mesophytic and their representative association is Nitraria tangutorum+ Pennisetum flacci-dum. The third vegetation type is grassland vegetation, which mainly consists of mesophytic and xerophytes, dis-tributed in the arid grassland zone. The representative association of the third vegetation type is the association of Anaeurolepidium secalium + Saussurea runcinata. Correlation analysis between the axes of DCA and envir-onmental soil factors shows that soil moisture content, organic matter, soil salt content and total nitrogen are the main environmental factors affecting the pattern of vegetation distribution along the biotope gradients from wetland to arid grassland. Other factors affecting the vegetation are microtopography and grazing pressure. Additionally, we have reported modifications and

  8. Land Surface Model and Particle Swarm Optimization Algorithm Based on the Model-Optimization Method for Improving Soil Moisture Simulation in a Semi-Arid Region.

    Science.gov (United States)

    Yang, Qidong; Zuo, Hongchao; Li, Weidong

    2016-01-01

    Improving the capability of land-surface process models to simulate soil moisture assists in better understanding the atmosphere-land interaction. In semi-arid regions, due to limited near-surface observational data and large errors in large-scale parameters obtained by the remote sensing method, there exist uncertainties in land surface parameters, which can cause large offsets between the simulated results of land-surface process models and the observational data for the soil moisture. In this study, observational data from the Semi-Arid Climate Observatory and Laboratory (SACOL) station in the semi-arid loess plateau of China were divided into three datasets: summer, autumn, and summer-autumn. By combing the particle swarm optimization (PSO) algorithm and the land-surface process model SHAW (Simultaneous Heat and Water), the soil and vegetation parameters that are related to the soil moisture but difficult to obtain by observations are optimized using three datasets. On this basis, the SHAW model was run with the optimized parameters to simulate the characteristics of the land-surface process in the semi-arid loess plateau. Simultaneously, the default SHAW model was run with the same atmospheric forcing as a comparison test. Simulation results revealed the following: parameters optimized by the particle swarm optimization algorithm in all simulation tests improved simulations of the soil moisture and latent heat flux; differences between simulated results and observational data are clearly reduced, but simulation tests involving the adoption of optimized parameters cannot simultaneously improve the simulation results for the net radiation, sensible heat flux, and soil temperature. Optimized soil and vegetation parameters based on different datasets have the same order of magnitude but are not identical; soil parameters only vary to a small degree, but the variation range of vegetation parameters is large. PMID:26991786

  9. JOJOBA: an oil plant for arid or semi-arid regions

    Energy Technology Data Exchange (ETDEWEB)

    Marull, J.E.

    1978-01-01

    Jojoba (Simmondsia chinesis) grows in regions with a rainfall of 250 to 450 mm, producing 4.5 kg seeds/tree after 36 months and attaining an average production of 13.8 kg seeds/tree when full grown. Productivity can be maintained for up to 100 years. Planting density is about 1600 plants/ha, at distances of 1.50 x 3.00 m. The seeds contain 50% edible oil, and the press-cake 35% proteins. The characteristics of the oil are listed.

  10. Jojoba, an oil plant for arid or semi-arid regions

    Energy Technology Data Exchange (ETDEWEB)

    Marull, J.E.

    1978-01-01

    Jojoba (Simmondsia chinensis) grows in regions with a rainfall of 250-450 mm, producing 4.5 kg seeds/tree after 36 months and attaining an average production of 13.8 kg seeds/tree when full grown. Productivity can be maintained for up to 100 years. Planting density is about 1600 plants/ha, at distances of 1.50 x 3.00 m. The seeds contain 50% edible oil, and the press-cake 35% proteins. The characteristics of the oil are listed.

  11. Impact of sublimation losses in the mass balance of glaciers in semi-arid mountain regions

    Science.gov (United States)

    Ayala, Alvaro; Pellicciotti, Francesca; Burlando, Paolo; MacDonell, Shelley; McPhee, James

    2016-04-01

    Glaciers in semiarid mountain regions may lose an important part of their winter snow accumulation through sublimation processes that are enhanced by the high-elevation, intense radiation and dry atmosphere of these environments. As glaciers in these regions secure freshwater resources to lower valleys during summer and drought periods, it is important to advance in a detailed quantification of their sublimation losses. However, logistical concerns and complex meteorological features make the measuring and modelling of glacier mass balances a difficult task. In this study, we estimated the spring-summer mass balances of Tapado and Juncal Norte glaciers in the semiarid Andes of north-central Chile by running a distributed energy balance model that accounts for melt, refreezing and sublimation from the surface and blowing snow. Meteorological input data were available from on-glacier Automatic Weather Stations (AWS) that were installed during the ablation season of years 2005-06, 2008-09, 2013-14 and 2014-15. Snow pits, ablation stakes and a time-lapse camera that provided surface albedo were also available. Distributed air temperature and wind speed were dynamically downscaled from NASA MERRA reanalysis using the software WINDSIM and validated against the data from the AWSs. The rest of the meteorological variables were distributed using statistical relations with air temperature derived from the AWSs data. Initial snow conditions were estimated using satellite images and distributed manual snow depth measurements. Preliminary results show that total ablation diminishes with elevation and that, during the early ablation season (October-November), melt is the main ablation component below 4500 m with sublimation dominating the ablation above this elevation. Above 4500 m an important fraction of meltwater refreezes during night. As the ablation season advances (December-February), melt extends to higher elevations, refreezing plays a smaller role and sublimation is

  12. Hunting strategies used in the semi-arid region of northeastern Brazil.

    Science.gov (United States)

    Alves, Rômulo R N; Mendonça, Lívia E T; Confessor, Maine V A; Vieira, Washington L S; Lopez, Luiz C S

    2009-01-01

    Hunting for wild animals is stimulated by the many different human uses of faunal resources, and these animals constitute important subsistence items in local communities in the Caatinga region. In order to gain access to these resources, hunters have developed a series of techniques and strategies that are described in the present work. The principal hunting techniques encountered were: waiting, especially directed towards hunting diurnal birds; calling ("arremedo"), a technique in which the hunters imitate the animal's call to attract it to close range; hunting with dogs, a technique mostly used for capturing mammals; tracking, a technique used by only a few hunters who can recognize and follow animal tracks; and "facheado", in which the hunters go out at night with lanterns to catch birds in their nests. Additionally, many animal species are captured using mechanical traps. The types of traps used by the interviewees were: dead-fall traps ("quixó"), iron-jaw snap traps ("arataca"), wooden cages with bait ("arapuca"), iron-cage traps ("gaiola'), "visgo", multi-compartment bird cages ("alçapão"), buried ground traps with pivoted tops ("fojo"), and nooses and cages for carnivorous. The choice of which technique to use depends on the habits of the species being hunted, indicating that the hunters possess a wide knowledge of the biology of these animals. From a conservation perspective, active hunting techniques (waiting, imitation, hunting with dogs, and "facheado") have the greatest impact on the local fauna. The use of firearm and dogs brought greater efficiency to hunting activities. Additional studies concerning these hunting activities will be useful to contribute to proposals for management plans regulating hunting in the region - with the objective of attaining sustainable use of faunal resources of great importance to the local human communities. PMID:19386121

  13. Hunting strategies used in the semi-arid region of northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Lopez Luiz CS

    2009-04-01

    Full Text Available Abstract Hunting for wild animals is stimulated by the many different human uses of faunal resources, and these animals constitute important subsistence items in local communities in the Caatinga region. In order to gain access to these resources, hunters have developed a series of techniques and strategies that are described in the present work. The principal hunting techniques encountered were: waiting, especially directed towards hunting diurnal birds; calling ("arremedo", a technique in which the hunters imitate the animal's call to attract it to close range; hunting with dogs, a technique mostly used for capturing mammals; tracking, a technique used by only a few hunters who can recognize and follow animal tracks; and "facheado", in which the hunters go out at night with lanterns to catch birds in their nests. Additionally, many animal species are captured using mechanical traps. The types of traps used by the interviewees were: dead-fall traps ("quixó", iron-jaw snap traps ("arataca", wooden cages with bait ("arapuca", iron-cage traps ("gaiola', "visgo", multi-compartment bird cages ("alçapão", buried ground traps with pivoted tops ("fojo", and nooses and cages for carnivorous. The choice of which technique to use depends on the habits of the species being hunted, indicating that the hunters possess a wide knowledge of the biology of these animals. From a conservation perspective, active hunting techniques (waiting, imitation, hunting with dogs, and "facheado" have the greatest impact on the local fauna. The use of firearm and dogs brought greater efficiency to hunting activities. Additional studies concerning these hunting activities will be useful to contribute to proposals for management plans regulating hunting in the region – with the objective of attaining sustainable use of faunal resources of great importance to the local human communities.

  14. Carbonaceous aerosol over semi-arid region of western India: Heterogeneity in sources and characteristics

    Science.gov (United States)

    Sudheer, A. K.; Aslam, M. Y.; Upadhyay, M.; Rengarajan, R.; Bhushan, R.; Rathore, J. S.; Singh, S. K.; Kumar, S.

    2016-09-01

    Carbonaceous species (elemental carbon (EC), organic carbon (OC), water-soluble organic carbon (WSOC)) and water-soluble inorganic species (Na+, NH4+, K+, Ca2 +, Mg2 +, Cl-, NO3-, SO42 -) in PM10 and PM2.5 from Ahmedabad and Jodhpur (urban and semi-urban locations, respectively) in western India were measured during May-September, 2011. Stable isotope composition of carbonaceous aerosol (δ13C of TC) in PM10 samples was also determined. Average EC concentration in PM10 at Ahmedabad was 1 μg m- 3 (range: 0.34 to 3.4 μg m- 3), almost 80% of which remained in PM2.5. Similarly, 70% of EC in PM10 (average: 0.9 μg m- 3) resided in PM2.5 at Jodhpur. Average OC concentration at Ahmedabad was 6.4 μg m- 3 and ~ 52% of this was found in PM2.5. On the contrary, OC concentration at Jodhpur was 40 μg m- 3, 80% of which was found in coarse particles contributing substantially to aerosol mass. δ13C of TC (average: - 27.5‰, range: - 29.6 to - 25.8‰) along with WSOC/EC ratio shows an increasing trend at Jodhpur suggesting the possibility of aging of aerosol, since aging results in enrichment of heavier isotope. OC and WSOC show significant correlations with K+ and not with EC, indicating biogenic origin of OC. Different size distributions are also exhibited by WSOC at the two stations. On the other hand, δ13C exhibits an inverse trend with sea-salt constituents at Ahmedabad, indicating the influence of air masses transported from the western/south-western region on carbonaceous aerosol. These results suggest that a strong heterogeneity exists in the sources of carbonaceous aerosol over this region and potential sources of non-combustion emissions such as bio-aerosol that need further investigation.

  15. Comparison of energy of irrigation regimes in sugar beet production in a semi-arid region

    Energy Technology Data Exchange (ETDEWEB)

    Topak, Ramazan; Sueheri, Sinan; Acar, Bilal [Department of Agricultural Structures and irrigation, Faculty of Agriculture, Selcuk University, 42075 Konya (Turkey)

    2010-12-15

    This study analyzed the effect of three levels of drip irrigation in sugar beet (Beta vulgaris L.) production in the Middle Anatolian region of Turkey. Two deficit irrigation treatments 75% and 50% of measured soil water depletion were compared with a full irrigation control treatment. In this paper, root yield, NEY (net energy yield), EEP (efficiency of energy production) and EWUE (energy water use efficiency) were investigated. Energy consumption of irrigation was found to be about 60% of total energy input in sugar beet production under full and deficit irrigation treatments. It was found that sugar beet had the highest EEP value (6.29) under the partial deficit irrigation (representing 75% of full irrigation). However, it was observed that full and severe deficit irrigation (representing 50% of full irrigation) treatments had a lower value. Results of this study indicated that the partial deficit drip irrigation technique can be applied in sugar beet production. In practice, deficit irrigation technique can reduce irrigation water use up to 25% compared to full irrigation technique. In addition, partial deficit drip irrigation technique may save 11.2% of total energy inputs, 16.1% of irrigation energy inputs, 21.2% of total fuel use and 25% of fuel use in irrigation. (author)

  16. Root density of cherry trees grafted on prunus mahaleb in a semi-arid region

    Science.gov (United States)

    Paltineanu, Cristian; Septar, Leinar; Gavat, Corina; Chitu, Emil; Oprita, Alexandru; Moale, Cristina; Lamureanu, Gheorghe; Vrinceanu, Andrei

    2016-07-01

    Root density was investigated using the trench method in a cherry (Prunus avium grafted on Prunus mahaleb) orchard with clean cultivation in inter-rows and in-row. Trenches of 1 m width and 1.2 m depth were dug up between neighbouring trees. The objectives of the paper were to clarify the spatial distribution of root density of cherry trees under the soil and climate conditions of the region to expand knowledge of optimum planting distance and orchard management for a broad area of chernozems. Some soil physical properties were significantly worsened in inter-rows versus in-row, mainly due to soil compaction, and there were higher root density values in in-row versus inter-rows. Root density decreased more intensely with soil depth than with distance from trees. The pattern of root density suggests that the cherry tree density and fruit yield could be increased. However, other factors concerning orchard management and fruit yield should also be considered. The results obtained have a potential impact to improve irrigation and fertilizer application by various methods, considering the soil depth and distance from trees to wet soil, in accordance with root development.

  17. Strategies for Developing Drought Tolerant Cowpea varieties for the Semi-Arid regions of Nigeria

    International Nuclear Information System (INIS)

    Drought, meaning the deviation of the total amount and or distribution of precipitation from the normal is an important factor that cause untold human suffering as well as social and economic loss for any nation. Its effects are often felt by places so remote from the area of occurrence. In the agricultural sector, where its effect are most felt, drought risk greatly reduce investment in agriculture. This will no doubt contribute to national food insecurity and social unrest. Of the measures often prescribed to combat the menace of drought include the development and planting of drought resistant/tolerant crop varieties. This paper discusses the strategies for developing drought tolerant cowpea varieties for the drought-prone regions of Nigeria. These strategies include the introduction and screening of candidate drought tolerant cowpea germplasm and their utilization in developing new improved genotypes. The screening of populations will be carried out by adopting novel screening techniques in the lab as well as in the field. In addition to utilizing existing genetic variation to develop varieties with tolerance to drought, new sources of variation will be created artificially for the various traits known to confer tolerance to drought in cowpea. In creating genetic variability for drought tolerance traits artificially, the potential of irradiation induced mutation will be exploited

  18. What Climate Conditions Enhance Hillslope Erosion in Semi-Arid Regions?

    Science.gov (United States)

    Pierce, J. L.; Riley, K. E.; Kenworthy, M.; Poulos, M. J.; Weppner, K.; Nelson, N.; Svenson, L.

    2011-12-01

    Researchers have long pondered the question of how climate and climate change influence rates and processes of erosion: this question has become more relevant in the face of ongoing and future anthropogenic warming. We examine evidence of hillslope erosion and sedimentation on alluvial fans over Holocene and Quaternary timescales throughout a range of ecosystems in Idaho, USA. Records of erosion include fire-related and non-fire related deposition on alluvial fans, and landscape-scale analysis of hillslope slope angles. Over Holocene timescales, five independent records of forest-fires and fire-related erosion from sagebrush steppe, pinion-juniper, ponderosa pine, lodgepole pine and mixed conifer ecosystems indicate that sedimentation rates and processes on alluvial fans vary temporally with Holocene climate and spatially with vegetation type. Despite variations in ecosystem type and associated fire regimes, all sites show similar broad-scale temporal patterns. The mid-Holocene (~4-8 ka) is characterized by few fire-related deposits and many non-fire related sheetflooding events (vs. debris flows); this relatively fire-free interval is punctuated by fire peaks and associated sheetflooding ~7-6 ka. As regional paleoclimatic reconstructions generally indicate this time was generally warm and dry the lack of fire is somewhat counterintuitive; however, decreased fuel loads, combined with perhaps a more stable climate may reduce fire and storm intensity and frequency. Late Holocene (last ~3 ka) cooler, wetter and more variable climates (as compared to the mid-Holocene) are characterized by increased fire activity at all sites, and more large debris flows. Medieval droughts correspond with major fire and debris flow peaks ~1000-800 cal yr BP; decadal to annual droughts during the generally cooler and wetter LIA also promote fire peaks ~500-300 cal yr BP. Modern observations of hillslope erosion indicate north-facing or moister slopes are characterized by dense vegetation

  19. Population dynamics of small mammals in semi-arid regions: a comparative study of demographic variability in two rodent species.

    OpenAIRE

    Lima, Mauricio; Stenseth, Nils Chr.; Leirs, Herwig; Jaksic, Fabián M

    2003-01-01

    The seasonally determined demographic structure of two semi-arid rodents, both agricultural pest species (the leaf-eared mouse (Phyllotis darwini) in Chile and the multimammate mouse (Mastomys natalensis) in Tanzania), is analysed using capture-mark-recapture (CMR) statistical models and measures for elasticity (the relative change in the growth rate due to a relative unit change in the parameter of concern) derived from projection linear matrix models. We demonstrate that reproduction and su...

  20. Temporal and spectral characteristics of aerosol optical depths in a semi-arid region of southern India

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, K. Raghavendra; Narasimhulu, K.; Reddy, R.R.; Gopal, K. Rama [Aerosol and Atmospheric Research Laboratory, Department of Physics Sri Krishnadevaraya University, Anantapur-515 055 (India); Reddy, L. Siva Sankara [Aerosol and Atmospheric Research Laboratory, Department of Physics Sri Krishnadevaraya University, Anantapur-515 055 (India)], E-mail: rajururreddy@yahoo.co.uk; Balakrishnaiah, G. [Aerosol and Atmospheric Research Laboratory, Department of Physics Sri Krishnadevaraya University, Anantapur-515 055 (India); Moorthy, K. Krishna; Babu, S. Suresh [Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram-695 022 (India)

    2009-04-01

    The spectral and temporal variations of aerosol optical depths (AOD) observed over Anantapur (a semi-arid region) located in the Southern part of India are investigated by analyzing the data obtained from a Multiwavelength Solar Radiometer (MWR) during January 2005-December 2006 (a total of 404 clear-sky observations) using the Langley technique. In this paper, we highlighted the studies on monthly, seasonal and spectral variations of aerosol optical depth and their implications. The results showed seasonal variation with higher values during pre-monsoon (March-May) and lower in the monsoon (June-November) season at all wavelengths. The pre-monsoon increase is found to be due to the high wind speed producing larger amounts of wind-driven dust particles. The post-monsoon (December-February) AOD values decrease more at higher wavelengths, indicating a general reduction in the number of bigger particles. Also during the post-monsoon, direction of winds in association with high or low pressure weather systems and the air brings more aerosol content to the region which is surrounded by a number of cement plants, lime kilns, slab polishing and brick making units. The quantity of AOD values in pre-monsoon is higher (low during post-monsoon) for wavelength, such as shortwave infrared (SWIR) or near infrared (NIR), which shows that coarse particles contribute more compare with the sub-micron particles. The composite aerosols near the surface follow suit with the share of the accumulation mode to the total mass concentration decreasing from {approx} 70% to 30% from post-monsoon to pre-monsoon. Coarse mode particle loading observed to be high during pre-monsoon and accumulation mode particles observed to be high during post-monsoon. The backward trajectories at three representative altitudes with source point at the observing site indicate a possible transport from the outflow regions into Bay of Bengal, southern peninsular India and Arabian Sea. The temporal variations of

  1. Relating surface backscatter response from TRMM precipitation radar to soil moisture: results over a semi-arid region

    Directory of Open Access Journals (Sweden)

    H. Stephen

    2010-02-01

    Full Text Available The Tropical Rainfall Measuring Mission (TRMM carries aboard the Precipitation Radar (TRMMPR that measures the backscatter (σ° of the surface. σ° is sensitive to surface soil moisture and vegetation conditions. Due to sparse vegetation in arid and semi-arid regions, TRMMPR σ° primarily depends on the soil water content. In this study we relate TRMMPR σ° measurements to soil water content (ms in the Lower Colorado River Basin (LCRB. σ° dependence on ms is studied for different vegetation greenness values determined through Normalized Difference Vegetation Index (NDVI. A new model of σ° that couples incidence angle, ms, and NDVI is used to derive parameters and retrieve soil water content. The calibration and validation of this model are performed using simulated and measured ms data. Simulated ms is estimated using the Variable Infiltration Capacity (VIC model and measured ms is acquired from ground measuring stations in Walnut Gulch Experimental Watershed (WGEW.

    σ° model is calibrated using VIC and WGEW ms data during 1998 and the calibrated model is used to derive ms during later years. The temporal trends of derived ms are consistent with VIC and WGEW ms data with a correlation coefficient (R of 0.89 and 0.74, respectively. Derived ms is also consistent with the measured precipitation data with R=0.76. The gridded VIC data is used to calibrate the model at each grid point in LCRB and spatial maps of the model parameters are prepared. The model parameters are spatially coherent with the general regional topography in LCRB. TRMMPR σ° derived soil moisture maps during May (dry and August (wet 1999 are spatially similar to VIC estimates with correlation 0.67 and 0.76, respectively. This research provides new

  2. Mashhad Wise Water Forum: a path to sustainable water resources management in a semi-arid region of Iran

    Science.gov (United States)

    Tabatabaee, Seyyed Alireza; Neyshaboori, Shahnaz; Basirat, Ali; Tavakoli Aminiyan, Samaneh; Mirbehrooziyan, Ahmad; Sakhdari, Hossein; Shafiei, Mojtaba; Davary, Kamran

    2016-04-01

    Water is key to sustainable development especially in semi-arid regions in which the main source of water provision is groundwater. Water has value from a social, economic and environmental perspective and is required to be managed within a sound, integrated socio-economic and environmental framework. Mashhad, the second big city in Iran, has been faced with rapid growth rates of population and economic activities. The groundwater in Mashhad basin has been overexploited to meet the increasing trend of water demand during the past 20 years. Consequently, the region has faced with water scarcity and water quality problems which originates from inefficient use and poor management. To tackle the water issue on a durable basis, within the economic, ecological, and political constraints (i.e. the integrated water resources management, IWRM concept), a Non-Governmental Organization (NGO), named as Mashhad Wise Water Forum (MWWF), has been established in 2013 that encompasses contribution of experts from academia, industry, and governmental policy-makers. The MWWF considers the UN-Water IWRM spiral conceptual model (which contains four stages: Recognizing and identifying; Conceptualizing; Coordinating and planning; Implementing, Monitoring and Evaluating) by implicating participatory water management (water users' involvement) methods in Mashhad basin. Furthermore, the MWWF has planned to look at all dimensions of water crisis (i.e. physical, economic, policy and institutional) particularly institutional dimension by gathering all stockholders, beneficiaries and experts in different parts of water policy making in Mashhad basin. The MWWF vision for Mashhad basin is achieving to sustainable equilibrium of water resources and consumptions in the basin by the prospect to 2040 year. So far, the MWWF has tried to understand and deal with regional diversity in legal systems as well as conflicts between private interests and public welfare in water allocation and management. At

  3. Hierarchical distance-based fuzzy approach to evaluate urban water supply systems in a semi-arid region

    OpenAIRE

    Yekta, Tahereh Sadeghi; Khazaei, Mohammad; Nabizadeh, Ramin; MAHVI, Amir Hossein; Nasseri, Simin; Yari, Ahmad Reza

    2015-01-01

    Hierarchical distance-based fuzzy multi-criteria group decision making was served as a tool to evaluate the drinking water supply systems of Qom, a semi-arid city located in central part of Iran. A list of aspects consisting of 6 criteria and 35 sub-criteria were evaluated based on a linguistic term set by five decision-makers. Four water supply alternatives including “Public desalinated distribution system”, “PET Bottled Drinking Water”, “Private desalinated water suppliers” and “Household d...

  4. Spatial Distribution of Aboveground Carbon Stock of the Arboreal Vegetation in Brazilian Biomes of Savanna, Atlantic Forest and Semi-Arid Woodland.

    Science.gov (United States)

    Scolforo, Henrique Ferraco; Scolforo, Jose Roberto Soares; Mello, Carlos Rogerio; Mello, Jose Marcio; Ferraz Filho, Antonio Carlos

    2015-01-01

    The objective of this study was to map the spatial distribution of aboveground carbon stock (using Regression-kriging) of arboreal plants in the Atlantic Forest, Semi-arid woodland, and Savanna Biomes in Minas Gerais State, southeastern Brazil. The database used in this study was obtained from 163 forest fragments, totaling 4,146 plots of 1,000 m2 distributed in these Biomes. A geographical model for carbon stock estimation was parameterized as a function of Biome, latitude and altitude. This model was applied over the samples and the residuals generated were mapped based on geostatistical procedures, selecting the exponential semivariogram theoretical model for conducting ordinary Kriging. The aboveground carbon stock was found to have a greater concentration in the north of the State, where the largest contingent of native vegetation is located, mainly the Savanna Biome, with Wooded Savanna and Shrub Savanna phytophysiognomes. The largest weighted averages of carbon stock per hectare were found in the south-center region (48.6 Mg/ha) and in the southern part of the eastern region (48.4 Mg/ha) of Minas Gerais State, due to the greatest predominance of Atlantic Forest Biome forest fragments. The smallest weighted averages per hectare were found in the central (21.2 Mg/ha), northern (20.4 Mg/ha), and northwestern (20.7 Mg/ha) regions of Minas Gerais State, where Savanna Biome fragments are predominant, in the phytophysiognomes Wooded Savanna and Shrub Savanna.

  5. Potential of the Thermal Infrared Wavelength Region to predict semi-arid Soil Surface Properties for Remote Sensing Monitoring

    Science.gov (United States)

    Eisele, Andreas; Chabrillat, Sabine; Lau, Ian; Hecker, Christoph; Hewson, Robert; Carter, Dan; Wheaton, Buddy; Ong, Cindy; Cudahy, Thomas John; Kaufmann, Hermann

    2014-05-01

    Digital soil mapping with the means of passive remote sensing basically relies on the soils' spectral characteristics and an appropriate atmospheric window, where electromagnetic radiation transmits without significant attenuation. Traditionally the atmospheric window in the solar-reflective wavelength region (visible, VIS: 0.4 - 0.7 μm; near infrared, NIR: 0.7 - 1.1 μm; shortwave infrared, SWIR: 1.1 - 2.5 μm) has been used to quantify soil surface properties. However, spectral characteristics of semi-arid soils, typically have a coarse quartz rich texture and iron coatings that can limit the prediction of soil surface properties. In this study we investigated the potential of the atmospheric window in the thermal wavelength region (long wave infrared, LWIR: 8 - 14 μm) to predict soil surface properties such as the grain size distribution (texture) and the organic carbon content (SOC) for coarse-textured soils from the Australian wheat belt region. This region suffers soil loss due to wind erosion processes and large scale monitoring techniques, such as remote sensing, is urgently required to observe the dynamic changes of such soil properties. The coarse textured sandy soils of the investigated area require methods, which can measure the special spectral response of the quartz dominated mineralogy with iron oxide enriched grain coatings. By comparison, the spectroscopy using the solar-reflective region has limitations to discriminate such arid soil mineralogy and associated coatings. Such monitoring is important for observing potential desertification trends associated with coarsening of topsoil texture and reduction in SOC. In this laboratory study we identified the relevant LWIR wavelengths to predict these soil surface properties. The results showed the ability of multivariate analyses methods (PLSR) to predict these soil properties from the soil's spectral signature, where the texture parameters (clay and sand content) could be predicted well in the models

  6. Establishment of a planted field with Mediterranean shrubs in Sardinia and its evaluation for climate mitigation and to combat desertification in semi-arid regions

    Directory of Open Access Journals (Sweden)

    De Dato GD

    2009-06-01

    Full Text Available Forested areas are important in arid and semi-arid regions primarily to combat desertification, but also to increase carbon sinks. To reverse the land degradation processes, restoration in the Mediterranean Basin had been frequently obtained by planting indigenous and exotic conifers, but it has been demonstrated that shrubs are nurse species for tree seedlings. Furthermore, planting indigenous shrubs is more efficient than allochthonous in restoring degraded soils. The aims of this work were: 1 to illustrate an experimental area in Sardinia used as a test-site to build up afforestation and reforestation activities in arid and semi-arid areas with autochthonous shrub species; 2 to show the results on plant survival and biomass one year after plantation trying to explain the role of different densities and specific compositions; 3 to hypothesize some trends of C accumulation of this “artificial” Mediterranean semi-arid shrubland by comparison with data found in the literature. The area is located in North West Sardinia, and is characterized by a Mediterranean climate. The revegetation was set up in February 2006, planting local species (Juniperus phoenicea, Pistacia lentiscus and Rosmarinus officinalis. Three densities and three specific compositions (monospecific plots with P. lentiscus, monospecific plots with J. phoenicea and mixed plots with the three cited species were combined. One month after plantation, almost all plants were alive, but mortality increased after summer, independently of the treatments, likely due to summer drought. During the first year, no differences among the densities and the specific compositions were observed. Total above-ground biomass was in the range of 0.8-3.0 g m-2. Below-ground biomass was in the range of 0.9-1.7 g m-2. A significant lower biomass was measured in October, especially in the Pistacia plots. Higher densities and plant mixing seemed to better perform, allowing establishment of species with a

  7. Co-occurrence of arsenic and fluoride in groundwater of semi-arid regions in Latin America: genesis, mobility and remediation.

    Science.gov (United States)

    Alarcón-Herrera, María Teresa; Bundschuh, Jochen; Nath, Bibhash; Nicolli, Hugo B; Gutierrez, Melida; Reyes-Gomez, Victor M; Nuñez, Daniel; Martín-Dominguez, Ignacio R; Sracek, Ondra

    2013-11-15

    Several million people around the world are currently exposed to excessive amounts of arsenic (As) and fluoride (F) in their drinking water. Although the individual toxic effects of As and F have been analyzed, there are few studies addressing their co-occurrences and water treatment options. Several studies conducted in arid and semi-arid regions of Latin America show that the co-occurrences of As and F in drinking water are linked to the volcaniclastic particles in the loess or alluvium, alkaline pH, and limited recharge. The As and F contamination results from water-rock interactions and may be accelerated by geothermal and mining activities, as well as by aquifer over-exploitation. These types of contamination are particularly pronounced in arid and semi-arid regions, where high As concentrations often show a direct relationship with high F concentrations. Enrichment of F is generally related to fluorite dissolution and it is also associated with high Cl, Br, and V concentrations. The methods of As and F removal, such as chemical precipitation followed by filtration and reverse osmosis, are currently being used at different scales and scenarios in Latin America. Although such technologies are available in Latin America, it is still urgent to develop technologies and methods capable of monitoring and removing both of these contaminants simultaneously from drinking water, with a particular focus towards small-scale rural operations.

  8. Jojoba - a promising plant for the semi-arid regions. [North America, plants, seeds, oils, waxes, growth, cultivation, lubricants, guayule, mesquite

    Energy Technology Data Exchange (ETDEWEB)

    Yermanos, D.M.

    1979-01-01

    As a result of the world-wide concern for conservation of resources and for the development of new renewable resources a great deal of attention has been directed towards the development of jojoba as a potential new crop for semi-arid regions. Jojoba grows wild in the Southwestern U.S. and N. Mexico, in areas where the annual precipitation is 4''-15''. Under cultivation it appears to grow satisfactorily in areas of marginal soil fertility, high salinity and high atmospheric temperatures. It appears to have no major natural enemies and to be tolerant to chemical treatments, if they were to become necessary. It is perennial with an assumed life span in excess of 150 years. Jojoba seed has an average weight of about 0.5 grams per seed, and it contains a unique liquid wax which is a superior lubricant and a potential replacement of whale oil, obtained from the sperm whale, and endangered species. Thus, jojoba has a double appeal, first as a potential crop of semi-arid regions requiring low cultural and energy inputs and second as a source of a valuable commodity. It should be pointed out that a cheap and abundant source of lubricants will disappear when our stock of fossil fuels are exhausted and that none of our new sources of energy have lubricants as by-products. Finally, jojoba could be grown with other companion crops such as guayule or mesquite for more diversified farming.

  9. A Two-source Energy Balance Model for estimating evapotranspiration over an olive orchard in a semi-arid region of Morocco

    Science.gov (United States)

    Ezzahar, Jamal; Chehbouni, Abdelghani; Er-Raki, Salah; Aouade, Ghizlane; Khabba, Said; Merlin, Olivier; Boulet, Gilles; Jarlan, Lionel

    2016-04-01

    In arid and semi-arid regions, about 85% of the available water is used for irrigated agriculture, and therefore a sound and efficient irrigation practice is an important step towards achieving sustainable management of water resources in these regions. In this regard, a better understanding of the water balance is essential for exploring water-saving techniques. One of the most important components of the water balance in semi-arid areas is the evapotranspiration (ET). Therefore, a precise estimation evapotranspiration is of crucial importance for agricultural water management. In this work, a two source energy balance model (TSEB) is used to estimate ET over an irrigated olive orchard located near located near to the Marrakech city (Centre of Morocco). In addition to its simplicity, TSEB does not require a large number of input parameters that are not readily available. Evapotranspiration and micrometeorological parameters were continuously measured during the year 2003 in order to evaluate the performance of TSEB estimates. The comparison between daily estimated and measured evapotranspiration yielded a good agreement although the complexity of the study surface with a correlation coefficient of 0.78 and a root mean square of 61.9wm-².

  10. An Overview of the Land Surface Processes Experiment (Laspex) over a Semi-Arid Region of India

    Science.gov (United States)

    Vernekar, K.G.; Sinha, S.; Sadani, L.K.; Sivaramakrishnan, S.; Parasnis, S.S.; Mohan, Brij; Dharmaraj, S.; Patil, M.N.; Pillai, J.S.; Murthy, B.S.; Debaje, S.B.; Bagavathsingh, A.

    To understand and quantify the land-surface-vegetation interactionwith the atmospheric boundary layer, and validate or improve upon the existing surfaceflux parameterization schemes in various weather forecast models, a LAnd SurfaceProcesses EXperiment (LASPEX), was designed and executed in the semi-arid regionof Gujarat, India during January 1997-December 1998. Micrometeorological tower observations,soil and vegetation parameters, radiation, turbulence and upper airobservations were taken continuously for two years at five sites, separated by about60-100 km from each other. Towers of 9 m height with instruments at four levels wereinstalled at sites that are agricultural fields and characterized with a variety of soilproperties, vegetation and diverse crops. An overview of the experiment is presented.Some results, such as the seasonal variation of surface energy balance and turbulence statistics,are discussed.

  11. Application of Dempster-Shafer theory, spatial analysis and remote sensing for groundwater potentiality and nitrate pollution analysis in the semi-arid region of Khuzestan, Iran.

    Science.gov (United States)

    Rahmati, Omid; Melesse, Assefa M

    2016-10-15

    Effective management and sustainable development of groundwater resources of arid and semi-arid environments require monitoring of groundwater quality and quantity. The aim of this paper is to develop a reasonable methodological framework for producing the suitability map for drinking water through the geographic information system, remote sensing and field surveys of the Andimeshk-Dezful, Khozestan province, Iran as a semi-arid region. This study investigated the delineation of groundwater potential zone based on Dempster-Shafer (DS) theory of evidence and evaluate its applicability for groundwater potentiality mapping. The study also analyzed the spatial distribution of groundwater nitrate concentration; and produced the suitability map for drinking water. The study has been carried out with the following steps: i) creation of maps of groundwater conditioning factors; ii) assessment of groundwater occurrence characteristics; iii) creation of groundwater potentiality map (GPM) and model validation; iv) collection and chemical analysis of water samples; v) assessment of groundwater nitrate pollution; and vi) creation of groundwater potentiality and quality map. The performance of the DS was also evaluated using the receiver operating characteristic (ROC) curve method and pumping test data to ensure its generalization ability, which eventually, the GPM showed 87.76% accuracy. The detailed analysis of groundwater potentiality and quality revealed that the 'non acceptable' areas covers an area of about 1479km(2) (60%). The study will provide significant information for groundwater management and exploitation in areas where groundwater is a major source of water and its exploration is critical to support drinking water need.

  12. Cost/benefit analysis of biomass energy supply options for rural smallholders in the semi-arid eastern part of Shinyanga Region in Tanzania

    Energy Technology Data Exchange (ETDEWEB)

    Wiskerke, W.T.; Dornburg, V.; Faaij, A.P.C. [Department of Science, Technology and Society, Utrecht University, Heidelberglaan 2, 3584 CS, Utrecht (Netherlands); Rubanza, C.D.K. [Tanzania Forestry Research Institute (TAFORI)/National Forest Resource Management and Agroforestry Centre (NACRAF), P.O. Box 1257, Shinyanga (Tanzania); Malimbwi, R.E. [Faculty of Forestry and Natural Resources, Sokoine University, P.O. Box 3010, Morogoro (Tanzania)

    2010-01-15

    This study analyzes the economic feasibility of sustainable smallholder bio-energy production under semi-arid conditions. The eastern part of Shinyanga region in Tanzania was chosen as a case study area. Three different sustainable biomass energy supply systems were compared by means of cost/benefit analysis: a small-scale forestation project for carbon sequestration, a short rotation woodlot and a Jatropha plantation, thereby using the produced Jatropha oil as a substitute for fuelwood or diesel. Rotational woodlots are most profitable with a Net Present Value of up to US${sub 2007} 1165/ha, a return on labour of up to US${sub 2007} 6.69/man-day and a fuelwood production cost of US${sub 2007} 0.53/GJ, compared to a local market price of US${sub 2007} 1.95/GJ. With a production cost of US${sub 2007} 19.60/GJ, Jatropha oil is too expensive to be used as an alternative for fuelwood. Instead it can be utilized economically as a diesel substitute, at an observed diesel cost of US${sub 2007} 1.49/l. The mean annual biomass increment (MAI) in semi-arid East Shinyanga is too low to collect sufficient benefits from trading forestation carbon credits under the Clean Development Mechanism (CDM) to cover the costs of forestation and forest management. (author)

  13. Cost/benefit analysis of biomass energy supply options for rural smallholders in the semi-arid eastern part of Shinyanga Region in Tanzania

    International Nuclear Information System (INIS)

    This study analyzes the economic feasibility of sustainable smallholder bio-energy production under semi-arid conditions. The eastern part of Shinyanga region in Tanzania was chosen as a case study area. Three different sustainable biomass energy supply systems were compared by means of cost/benefit analysis: a small-scale forestation project for carbon sequestration, a short rotation woodlot and a Jatropha plantation, thereby using the produced Jatropha oil as a substitute for fuelwood or diesel. Rotational woodlots are most profitable with a Net Present Value of up to US$2007 1165/ha, a return on labour of up to US$2007 6.69/man-day and a fuelwood production cost of US$2007 0.53/GJ, compared to a local market price of US$2007 1.95/GJ. With a production cost of US$2007 19.60/GJ, Jatropha oil is too expensive to be used as an alternative for fuelwood. Instead it can be utilized economically as a diesel substitute, at an observed diesel cost of US$2007 1.49/l. The mean annual biomass increment (MAI) in semi-arid East Shinyanga is too low to collect sufficient benefits from trading forestation carbon credits under the Clean Development Mechanism (CDM) to cover the costs of forestation and forest management. (author)

  14. A Case Study of the Impacts of Dust Aerosols on Surface Atmospheric Variables and Energy Budgets in a Semi-Arid Region of China

    Institute of Scientific and Technical Information of China (English)

    LING Xiao-Lu; GUO Wei-Dong; ZHANG Le; ZHANG Ren-Jian

    2010-01-01

    The authors present a case study investigatingthe impacts of dust aerosols on surface atmospheric variables and energy budgets in a semi-arid region of China.Enhanced observational meteorological data, radiative fluxes, near-surface heat fluxes, and concentrations of dust aerosols were collected from Tongyu station, one of the reference sites of the International Coordinated Energy and Water Cycle Observations Project (CEOP), during a typical dust storm event in June 2006. A comprehensive analysis of these data show that in this semi-arid area, higher wind velocities and a continuously reduced air pressure were identified during the dust storm period.Dust storm events are usually associated with low relative humidity weather conditions, which result in low latent heat flux values. Dust aerosols suspended in the air decrease the net radiation, mainly by reducing the direct solar radiation reaching the land surface. This reduction in net radiation results in a decrease in soil temperatures at a depth of 2 cm. The combination of increased air temperature and decreased soil temperature strengthens the energy exchange of the atmosphere-earth system, increasing the surface sensible heat flux. After the dust storm event,the atmosphere was dominated by higher pressures and was relatively wet and cold. Net radiation and latent heat flux show an evident increase, while the surface sensible heat flux shows a clear decrease.

  15. Utilização de água salina e condicionador de solo na produção de beterraba no semi-árido brasileiro Effect of saline water and soil conditioner on sugar beet yield in the Brazilian semi-arid region

    Directory of Open Access Journals (Sweden)

    Gilberto G. Cordeiro

    1999-03-01

    Full Text Available O experimento foi conduzido no Campo Experimental da Embrapa Semi-Árido em Petrolina - PE, no primeiro semestre de 1997 com o objetivo de avaliar o efeito de diferentes níveis de salinidade da água de irrigação e do condicionador de solo Sper Sal (ácido polimaléico na produção de beterraba (Beta vulgaris L., cultivar Early Wonder. O delineamento experimental foi de blocos ao acaso com quatro repetições. Os tratamentos foram: água com condutividade elétrica de 0,1 (água do Rio São Francisco - testemunha 4 e 8 dS/m e água com condutividade elétrica 0,1, 4 e 8 dS/m mais Sper Sal, com parcelas de 2 m². Os resultados obtidos mostraram que as produtividades variaram de 20,2 a 65,4 t/ha para os tratamentos irrigados com água salina mais Sper Sal e água do Rio São Francisco, respectivamente. Não se verificou diferença significativa na produtividade quando do uso de água com níveis de salinidade de 4 e 8 dS/m, cujas produtividades foram 29,4 e 26,3 t/ha respectivamente. Nos tratamentos com Sper Sal, observou-se que na concentração salina de 4 dS/m, o condicionador de solo demonstrou ser mais eficiente, em relação à concentração de 8 dS/m.An experiment was carried out at an experimental field in Embrapa Semi-arid, Petrolina - PE, during the first semester of 1997, with the objective of evaluating the effect of different irrigation water salinity levels, with and without the soil conditioner Sper Sal (polymaleic acid, on the yield of sugar beet (Beta vulgaris L., cv. Early Wonder. The experiment was set up in complete randomized block design, with four replications. Six treatments were tested: water with electrical conductivity of 0.1 (control, 4 and 8 dS/m, and the levels of electrical conductivity cited above plus Sper salt. The size of the plots was 2m². The results obtained showed that the yield varied from 20.2 to 65.4 t/ha, respectively, for irrigation treatments of saline with Sper Sal and water from the S

  16. Coexistence and geographical distribution of Leguminosae in an area of Atlantic forest in the semi-arid region of Brazil

    Institute of Scientific and Technical Information of China (English)

    Jacira R. LIMA; Vidal F. MANSANO; Francisca S. ARA(U)JO

    2012-01-01

    Understanding the factors that affect plant species distribution and coexistence in areas with high plant species diversity is a challenge for ecologists.According to some authors,species occupy specific niches,but for others,species coexistence and geographical distribution patterns are random.Floristic composition of the family Leguminosae was studied on moist and dry slopes of the Baturité mountains in semi-arid northeastern Brazil and was compared with findings for other plant formations elsewhere in Brazil.Substantial floristic differences were found between the moist windward and dry leeward slopes of the Baturité mountains despite their close geographical proximity.The leeward slope was slightly more diverse than the windward slope.Similarity analyses showed that the windward face is floristically allied to the Amazon forest,whereas the leeward slope is similar to other dry-area formations of northeastern Brazil,such as thorny woodland (caatinga) and seasonal forests.The strong floristic differences that were observed between the windward and leeward slopes corroborate the theory of ecological niche conservatism,which holds that species occurrence is closely linked to environmental factors,such as temperature and precipitation.

  17. Daily global solar radiation modelling using multi-layer perceptron neural networks in semi-arid region

    Directory of Open Access Journals (Sweden)

    Mawloud GUERMOUI

    2016-07-01

    Full Text Available Accurate estimation of Daily Global Solar Radiation (DGSR has been a major goal for solar energy application. However, solar radiation measurements are not a simple task for several reasons. In the cases where data are not available, it is very common the use of computational models to estimate the missing data, which are based mainly of the search for relationships between weather variables, such as temperature, humidity, sunshine duration, etc. In this respect, the present study focuses on the development of artificial neural network (ANN model for estimation of daily global solar radiation on horizontal surface in Ghardaia city (South Algeria. In this analysis back-propagation algorithm is applied. Daily mean air temperature, relative humidity and sunshine duration was used as climatic inputs parameters, while the daily global solar radiation (DGSR was the only output of the ANN. We have evaluated Multi-Layer Perceptron (MLP models to estimate DGSR using three year of measurement (2005-2008. It was found that MLP-model based on sunshine duration and mean air temperature give accurate results in term of Mean Absolute Bias Error, Root Mean Square Error, Relative Square Error and Correlation Coefficient. The obtained values of these indicators are 0.67 MJ/m², 1.28 MJ/m², 6.12%and 98.18%, respectively which shows that MLP is highly qualified for DGSR estimation in semi-arid climates.

  18. Pandemic influenza A (H1N1 2009: epidemiological analysis of cases in a tropical/semi-arid region of Brazil

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    Roberto da Justa Pires Neto

    2013-04-01

    Full Text Available Introduction The year 2009 marked the beginning of a pandemic caused by a new variant of influenza A (H1N1. After spreading through North America, the pandemic influenza virus (H1N1 2009 spread rapidly throughout the world. The aim of this study was to describe the clinical and epidemiological characteristics of cases of pandemic influenza in a tropical/semi-arid region of Brazil. Methods A retrospective study analyzed all suspected cases of pandemic influenza (H1N1 2009 reported in the Ceará State through the National Information System for Notifiable Diseases during the pandemic period between 28 April, 2009 and November 25, 2010. Results A total of 616 suspected cases were notified, 58 (9.4% in the containment phase and 558 (90.6% in the mitigation phase. Most cases were of affected young people resident in the City of Fortaleza, the largest urban center in the State of Ceará. The most frequent symptoms presented by the cases with confirmed infection were fever, cough, myalgia, arthralgia, and nasal congestion. Mortality rate was 0.0009/1,000 inhabitants and lethality was 5.6%. Deaths were observed only in the mitigation phase. Mortality rates were similar for both sexes but were higher in the age group under 5 years. Conclusions The study suggests that the influenza A (H1N1 pandemic in this tropical/semi-arid region had a lower magnitude when compared to states in the Southern and Southeastern regions of Brazil.

  19. ESTIMATION OF EXTRACELLULAR LIPOLYTIC ENZYME ACTIVITY BY THERMOPHILIC BACILLUS SP. ISOLATED FROM ARID AND SEMI-ARID REGION OF RAJASTHAN, INDIA

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    Deeksha Gaur

    2012-10-01

    Full Text Available Thermophilic organisms can be defined as, micro-organisms which are adapted to survive at high temperatures. The enzymes secreted by thermophilic bacteria are capable of catalyzing biochemical reactions at high temperatures. Thermophilic bacteria are able to produce thermostable lipolytic enzymes (capable of degradation of lipid at temperatures higher than mesophilic bacteria. Therefore, the isolation of thermophilic bacteria from natural sources and their identification are quite beneficial in terms of discovering thermostable lipase enzymes. Due to great temperature fluctuation in hot arid and semi-arid region of Rajasthan, this area could serve as a good source for new thermophilic lipase producing bacteria with novel industrially important properties. The main objective of this research is the isolation and estimation of industrially important thermophilic lipase enzyme produced by thermophilic bacteria, isolated from arid and semi-arid region of Rajasthan. For this research purpose soil samples were collected from Churu, Sikar and Jhunjunu regions of Rajasthan. Total 16 bacterial strains were isolated and among only 2 thermostable lipolytic enzyme producing bacteria were charcterized. The thermostable lipolytic enzyme was estimated by qualitative and quantitative experiments. The isolates were identified as Bacillus sp. by microscopic, biochemical and molecular characterization. The optimum enzyme activity was observed at pH 8, temperature 60°C and 6% salt concentrations at 24 hrs time duration. Lipolytic enzyme find useful in a variety of biotechnological fields such as food and dairy (cheese ripening, flavour development, detergent, pharmaceutical (naproxen, ibuprofen, agrochemical (insecticide, pesticide and oleochemical (fat and oil hydrolysis, biosurfactant synthesis industries. Lipolytic enzyme can be further used in many newer areas where they can serve as potential biocatalysts.

  20. Future Water Management in the South Platte River Basin: Impacts of Hydraulic Fracturing, Population, Agriculture, and Climate Change in a Semi-Arid Region.

    Science.gov (United States)

    Walker, E. L.; Hogue, T. S.; Anderson, A. M.; Read, L.

    2015-12-01

    In semi-arid basins across the world, the gap between water supply and demand is growing due to climate change, population growth, and shifts in agriculture and unconventional energy development. Water conservation efforts among residential and industrial water users, recycling and reuse techniques and innovative regulatory frameworks for water management strive to mitigate this gap, however, the extent of these strategies are often difficult to quantify and not included in modeling water allocations. Decision support systems (DSS) are purposeful for supporting water managers in making informed decisions when competing demands create the need to optimize water allocation between sectors. One region of particular interest is the semi-arid region of the South Platte River basin in northeastern Colorado, where anthropogenic and climatic effects are expected to increase the gap between water supply and demand in the near future. Specifically, water use in the South Platte is impacted by several high-intensity activities, including unconventional energy development, i.e. hydraulic fracturing, and large withdrawals for agriculture; these demands are in addition to a projected population increase of 100% by 2050. The current work describes the development of a DSS for the South Platte River basin, using the Water Evaluation and Planning system software (WEAP) to explore scenarios of how variation in future water use in the energy, agriculture, and municipal sectors will impact water allocation decisions. Detailed data collected on oil and gas water use in the Niobrara shale play will be utilized to predict future sector use. We also employ downscaled climate projections for the region to quantify the potential range of water availability in the basin under each scenario, and observe whether or not, and to what extent, climate may impact management decisions at the basin level.

  1. Comparison of satellite microwave backscattering (ASCAT and visible/near-infrared reflectances (PARASOL for the estimation of aeolian aerodynamic roughness length in arid and semi-arid regions

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    C. Prigent

    2012-04-01

    Full Text Available Previous studies examined the possibility to estimate the aeolian aerodynamic roughness length from satellites, either from visible/near-infrared observations or from microwave backscattering measurements. Here we compare the potential of the two approaches and propose to merge the two sources of information to benefit from their complementary aspects, i.e. the high spatial resolution of the visible/near-infrared (PARASOL part of the A-Train and the independence from atmospheric contamination of the active microwaves (ASCAT on board MetOp. A global map of the aeolian aerodynamic roughness length at 6 km resolution is derived, for arid and semi-arid regions. It shows very good consistency with the existing information on the properties of these surfaces. The dataset is available to the community, for use in atmospheric dust transport models.

  2. Comparison of satellite microwave backscattering (ASCAT and visible/near-infrared reflectances (PARASOL for the estimation of aeolian aerodynamic roughness length in arid and semi-arid regions

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    C. Prigent

    2012-11-01

    Full Text Available Previous studies examined the possibility to estimate the aeolian aerodynamic roughness length from satellites, either from visible/near-infrared observations or from microwave backscattering measurements. Here we compare the potential of the two approaches and propose to merge the two sources of information to benefit from their complementary aspects, i.e. the high spatial resolution of the visible/near-infrared (6 km for PARASOL that is part of the A-Train and the independence from atmospheric contamination of the active microwaves (ASCAT on board MetOp with a lower spatial resolution of 25 km. A global map of the aeolian aerodynamic roughness length at 6 km resolution is derived, for arid and semi-arid regions. It shows very good consistency with the existing information on the properties of these surfaces. The dataset is available to the community, for use in atmospheric dust transport models.

  3. The photovoltaic solar technology in a semi-arid Piaui region: case study; A tecnologia solar fotovoltaica no semi-arido piauiense: estudo de caso

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, Albemerc Moura de; Trigoso, Federico B. Morante [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Centro de Engenharia, Modelagem e Ciencias Sociais Aplicadas. Programa de Pos Graduacao em Energia

    2008-07-01

    The following work has as objective to present some results of a research of field carried through in the Piaui semi-arid region that it aimed at to verify the use of the photovoltaic solar technology. For this six questionnaires in three rural communities of three municipal territories of the State in the valley of the river Caninde had been applied. It was verified that due to lack of maintenance of these systems good part of them left to still function in the first years of its installation. Although this almost all the interviewed ones had revealed signal of approval to the electric energy proceeding from these systems for the community use, however they had questioned the lack of maintenance of these and had revealed interested in possessing access in its residences of this so important good is useful, the electricity. (author)

  4. Multifonctionnalité de l'agriculture familiale et diversification des activités dans le sertão semi-aride de l'État de Bahia (Brésil)

    OpenAIRE

    Bittencourt Machado, Gustavo

    2009-01-01

    This thesis intends to understand the multifunctionality of the familial agriculture by the theoretical, conceptual and juridical approach according to the public policies that recognize the agricultural public functions or tasks for the semi-arid regions. The case study is the brazilian semi-arid sertão, specially the Sisal Territory, in the State of Bahia, using the Agrarian System Analysis-diagnostic. The agricultural multifonctionality is studied with their public functions, considering t...

  5. Occurrence and identification of the etiologic agents of plant diseases in cactus (Opuntia ficus-indica Mill. in the semi-arid region of Paraiba

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    Anne Evelyne Franco de Souza

    2010-09-01

    Full Text Available Cactus forage (Opuntia ficus-indica Mill., intensely cultivated in dry regions of northeast Brazil, although well adapted to the harsh semi-arid climate is affected by major problems such as pests and diseases, responsible for significant losses in production. This study aimed to investigate the occurrence and diversity of the etiologic agents of diseases of cactus cultivated in 38 municipalities in the semi-arid region of Paraiba. The analyses were conducted and processed at the Laboratory of Phytopathology of the Centro de Ciências Agrárias da Universidade Federal da Paraíba, in Areia – PB. Starting from sick cladodes isolations, multiplications and identifications of the found microorganisms were made. The identification of the microorganisms was achieved through observations of the macro and micromorphological characteristics of the cultures and tests of Gram and pathogenicity. Great incidence and diversity of microorganisms was verified in the cacti researched, but the highest occurrence was mainly that of fungus. The fungi of widest occurrence were: Scytallidium lignicola, Alternate tenuis, Macrophomina phaseolina, Cladosporium cladosporides, Lasiodiplodia theobromae, Fusarium oxysporum f. sp. opuntiarum, Curvularia lunata, Aspergillus niger, Nigrospora sphaerica, Colletotrichum gloeosporioides, Exserohilum turcicum, Pestalotia pitospora, Rhizopus stolonifer, Rhizoctonia solani and Sphaceloma protearum. A bacterium was also detected that was suspected to belong to the Erwinia sp. strain. Satisfaction of the Postulates of Koch proved the infectious nature of the detected microorganisms. High occurrence of the fungus S. lignicola, an agent of scale rot disease in 100% of the places researched, was observed. This fact is of great concern, since the progression of the disease can cause significant losses in production.

  6. Modelling forest lines and forest distribution patterns with remote sensing data in a mountainous region of semi-arid Central Asia

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    M. Klinge

    2014-10-01

    Full Text Available Satellite images and digital elevation models provide an excellent database to analyse forest distribution patterns and forest limits in the mountain regions of semi-arid Central Asia at the regional scale. For the investigation area in the northern Tien Shan a strong relation between forest distribution and climate conditions could be found. Additionally areas of potential human impact on forested areas are identified at lower elevations near the mountain border based on an analysis of the differences of climatic preconditions and present occurrence of forest stands. The distribution of spruce (Picea schrenkiana forests is hydrologically limited by a minimum annual precipitation of 250 mm and thermally by a minimum monthly mean temperature of 5 °C during the growing season. While the actual lower forest limit increases from 1600 m a.s.l. in the northwest to 2600 m a.s.l. in the southeast, the upper forest limit takes the same course from 1800 to 2900 m a.s.l. In accordance with the main wind directions, the steepest gradient of both forest lines and the greatest local vertical extent of the forest belt of 500 to 600 m and maximum 900 m occur at the northern and western mountain fronts. The forests in the investigation area are strongly restricted to north facing-slopes, which is a common feature in semi-arid Central Asia. Based on the presumption that variations in local climate conditions are a function of topography, the potential forest extent was analysed with regard to the parameters slope, aspect, solar radiation input and elevation. All four parameters showed a strong relationship to forest distribution, yielding a total potential forest area that is 3.5 times larger than the present forest remains of 502 km2.

  7. Ectoparasite Infestations and Canine Infection by Rickettsiae and Ehrlichiae in a Semi-Arid Region of Northeastern Brazil.

    Science.gov (United States)

    Araes-Santos, Ana Isabel; Moraes-Filho, Jonas; Peixoto, Renata M; Spolidorio, Mariana G; Azevedo, Sérgio S; Costa, Mateus M; Labruna, Marcelo B; Horta, Mauricio C

    2015-11-01

    This study investigated the prevalence of Rickettsia spp. and Ehrlichia canis infection in dogs and their ectoparasites from rural and urban areas of two municipalities, Petrolina and Juazeiro, within a semiarid region (Caatinga biome) of northeastern Brazil, by immunofluorescence assay (IFA) and polymerase chain reaction (PCR). Overall, 12.1% (61/504) and 23.0% (116/504) of canine plasma samples had antibodies reactive to Rickettsia spp. and E. canis. E. canis DNA was detected by PCR in 8.3% (42/504) of canine blood samples, whereas no blood sample was positive for Rickettsia spp. The infection by E. canis was determined by PCR in 4.9% (14/285) Rhipicephalus sanguineus sensu lato (s.l.) ticks and by Rickettsia felis in 1.1% (3/285) and 40.6% (74/182) ticks and fleas, respectively. Multivariate regression analyses revealed that canine seropositivity to Rickettsia spp. was associated statistically with the variables "to reside in Petrolina" and "presence of ectoparasites." Our results indicate that canine infection by E. canis might be endemic in the Caatinga biome as it is in other Brazilian biomes. Although no previous serosurvey for Rickettsia spp. has been conducted on dogs from the Caatinga biome, our values are much lower than the ones reported for rural dogs from other Brazilian biomes. These differences are likely related to the semiarid climate of the aatinga biome, which minimizes the exposure of rural dogs to Amblyomma spp. ticks, the most common vectors of Rickettsia spp. in Brazil. Considering that dogs are excellent sentinels for human exposure to Rickettsia spp., we can infer that the risks of human acquiring tick-borne rickettsiosis in the Caatinga region of the present study are low. The rickettsial infection rates in fleas and ticks were not related to canine seropositivity; i.e., areas with higher Rickettsia infection rates in fleas had the lowest canine seroreactivity to Rickettsia spp.

  8. Joint meteorological and hydrological drought model: a management tool for proactive water resources planning of semi-arid regions

    Science.gov (United States)

    Modaresi Rad, Arash; Ahmadi Ardakani, Samira; Ghahremani, Zahra; Ghahreman, Bijan; Khalili, Davar

    2016-04-01

    Conventionally drought analysis has been limited to single drought category. Utilization of models incorporating multiple drought categories, can relax this limitation. A copula-based model is proposed, which uses meteorological and hydrological drought indices to assess drought events for ultimate management of water resources, at small scales, i.e., sub-watersheds. The study area is a sub basin located at Karkheh watershed (western Iran), utilizing 41-year data of 4 raingauge stations and one hydrometric station located upstream and at the outlet respectively. Prior to drought analysis, time series of precipitation and streamflow records are investigated for possible dependency/significant trend. Considering the semi-arid nature of the study area, boxplots are utilized to graphically capture the rainy months, which used to evaluate the degree of correlation between streamflow and precipitation records via nonparametric correlations and bivariate tail dependence. Time scales of 3- and 12-month are considered, which are used to study vulnerability of early vegetation establishment and long-term ecosystem resilience, respectively. Among four common goodness of fit tests, the Cramér-von-Mises is found preferable for defining copula distribution functions through Akaike & Bayesian information criteria and coefficient of determination. Furthermore the uncertainty associated with different copula models is measured using the concept of entropy. A new bivariate drought modeling approach is proposed through copulas. The proposed index, named standardized precipitation-streamflow index (SPSI) is compared with two separate indices of streamflow drought index (SDI) and standardized precipitation index (SPI). According to results, the SPSI could detect onset of droughts dominated by precipitation as is similarly indicated by SPI index. It also captures discordant case of normal period precipitation with dry period streamflow and vice versa. Finally, combination of severity

  9. Políticas públicas de recursos hídricos para o semi-árido Public water resources policy for the semi-arid region

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    José Almir Cirilo

    2008-01-01

    Full Text Available As características climáticas e socioeconômicas do semi-árido brasileiro requerem tecnologias específicas de utilização e conservação dos recursos hídricos. É preciso analisar as alternativas de obtenção de água para usos diversos. Em contraposição às formas tradicionais de acumular água em pequenos reservatórios de superfície (açudes e perfuração de poços no cristalino, têm-se buscado alternativas como poços de grande profundidade nas áreas sedimentares, metodologias para redução da evaporação e controle da salinização, destinação e uso de efluentes. Por fim, obras de integração de bacias hidrográficas e transporte de água a grande distância começam a ser construídas na região. A abordagem dessas diferentes políticas hídricas para o semi-árido é o objetivo deste trabalho.The climatic, social and economic characteristics in the Brazilian semi-arid region require specific technologies of water resources uses and conservation. So, many alternatives for clean water acquisition must be analyzed. In opposition to the traditional way of accumulating water in small surface reservoirs and perforation of wells in crystalline terrains, alternatives have been looking like great depth wells in sedimentary areas, methodologies for evaporation reduction and salinization control, destination and use of effluents. Finally, works for river basins integration and water transport over long distances are starting to be built in Northeast region. The approach in those water policies for the Brazilian semi-arid region is the purpose of this paper.

  10. How to identify groundwater-caused thermal anomalies in lakes based on multi-temporal satellite data in semi-arid regions

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    U. Mallast

    2013-04-01

    Full Text Available Information on groundwater discharge over large spatial scales are essential for groundwater management particularly in (semi- arid regions. If discharge areas are known, direct measurements over larger spatial scales are complicated to obtain by conventional means, why thermal remote sensing is increasingly applied to localize and quantify groundwater discharge. In this context, mostly unconsidered is (i the influence of surface-runoff that can negatively affect groundwater focused studies and (ii the representativeness of remotely sensed groundwater discharge based on single thermal images, against the background of discharge intermittency. Addressing these issues we apply a multi-temporal SST data approach based on 19 Landsat ETM+ band 6.2 (high gain data from the year 2000 until 2002 at the example of the (semi-arid vicinity of Dead Sea. To be independent of auxiliary rain data we develop a novel approach to identify surface-runoff influenced images solely using image statistics. Compared to foregoing rain events the result reveals a general influence-time of at least two days, but also that a simple time-difference criterion to exclude possible surface-runoff is not advisable. In the second part of the study we evaluate the significance of six statistical measures calculated on a per-pixel basis on the remaining 12 surface-runoff uninfluenced sea-surface-temperature (SST data using in situ discharge measurements of the Israel Hydrological Service (IHS. We found that the spatial patterns of the standard deviation and range on the SST data series best fit to the IHS observed discharge locations and hence are suitable for detecting groundwater discharge areas.

  11. Determination of unit nutrient loads for different land uses in wet periods through modelling and optimization for a semi-arid region

    Science.gov (United States)

    Özcan, Zeynep; Kentel, Elçin; Alp, Emre

    2016-09-01

    Diffuse pollution abatement has been a challenge for decision-makers because of the intermittent nature and difficulty of identifying impacts of non-point sources. Depending on the degree of complexity of the system processes and constraints related to time, budget and human resources, variety of tools are used in diffuse pollution management. Decision-makers prefer to use rough estimates that require limited time and budget, in the preliminary assessment of diffuse pollution. The unit pollution load method which is based on the pollution generation rate per unit area and time for a given land use can aid decision-makers in the preliminary assessment of diffuse pollution. In this study, a deterministic distributed watershed model, SWAT is used together with nonlinear optimization models to estimate unit nutrient pollution loads during wet periods for different land use classes for the semi-arid Lake Mogan watershed that is dominated by agricultural activities. Extensive data sets including in-stream water quality and flowrate measurements, meteorological data, land use/land cover (LULC) map developed using remote sensing algorithms, information about agricultural activities, and soil data are used to calibrate and verify the hydraulic and water quality components of SWAT model. Results show that the unit total nitrogen (TN) and total phosphorus (TP) loads (0.46 kg TN/ha/yr and 0.07 kg TP/ha/yr) generated from the watershed during wet periods are very close to the minimum values of the loads specified in the literature and highly depend on the variations in rainfall. Estimated unit nutrient loads both at watershed scale and for different land use classes can be used to assess diffuse pollution control measures for similar regions with semi-arid conditions and heavy agricultural activity.

  12. Mapping of bare soil surface parameters from TerraSAR-X radar images over a semi-arid region

    Science.gov (United States)

    Gorrab, A.; Zribi, M.; Baghdadi, N.; Lili Chabaane, Z.

    2015-10-01

    The goal of this paper is to analyze the sensitivity of X-band SAR (TerraSAR-X) signals as a function of different physical bare soil parameters (soil moisture, soil roughness), and to demonstrate that it is possible to estimate of both soil moisture and texture from the same experimental campaign, using a single radar signal configuration (one incidence angle, one polarization). Firstly, we analyzed statistically the relationships between X-band SAR (TerraSAR-X) backscattering signals function of soil moisture and different roughness parameters (the root mean square height Hrms, the Zs parameter and the Zg parameter) at HH polarization and for an incidence angle about 36°, over a semi-arid site in Tunisia (North Africa). Results have shown a high sensitivity of real radar data to the two soil parameters: roughness and moisture. A linear relationship is obtained between volumetric soil moisture and radar signal. A logarithmic correlation is observed between backscattering coefficient and all roughness parameters. The highest dynamic sensitivity is obtained with Zg parameter. Then, we proposed to retrieve of both soil moisture and texture using these multi-temporal X-band SAR images. Our approach is based on the change detection method and combines the seven radar images with different continuous thetaprobe measurements. To estimate soil moisture from X-band SAR data, we analyzed statistically the sensitivity between radar measurements and ground soil moisture derived from permanent thetaprobe stations. Our approaches are applied over bare soil class identified from an optical image SPOT / HRV acquired in the same period of measurements. Results have shown linear relationship for the radar signals as a function of volumetric soil moisture with high sensitivity about 0.21 dB/vol%. For estimation of change in soil moisture, we considered two options: (1) roughness variations during the three-month radar acquisition campaigns were not accounted for; (2) a simple

  13. Hydrological Connectivity and Science and Policy Integration Issues for Aquatic Resource Jurisdictional Determinations in a Semi-Arid Region of the Western U.S

    Science.gov (United States)

    Caruso, B. S.

    2012-12-01

    Rivers and streams are becoming increasingly stressed and degraded, and wetlands lost, due to human development and associated management policies and actions that are generally ineffective for aquatic resources protection and restoration. In the semi-arid western U.S., these issues are more severe due to the limited quantity of water and aquatic resources, the magnified role of their ecological services in drier landscapes, and increasing impacts from urbanization and energy development. However, a significant disconnect between policy and science exists that leads to continued degradation of surface waters. Supreme Court decisions and joint Federal agency guidance for determining jurisdiction as 'waters of the US' that can be protected under Clean Water Act Section 404 (permitting discharge of dredged and fill materials into wetlands and other waters) are good examples of this disconnect. The hydrological and ecological connectivity of intermittent and ephemeral streams and wetlands with downstream navigable waters is a critical issue that must be evaluated to determine jurisdiction, but this can be a complex endeavour in semi-arid regions. The hydrological connectivity and key science and policy integration issues for stream and wetland jurisdictional determinations (JDs) were evaluated for a semi-arid region of the western U.S. (Environmental Protection Agency [EPA] Region 8), including much of the Rocky Mountains, Great Plains and Colorado Plateau. The key scientific approaches recommended in the agency guidance were analyzed in detail. An evaluation was performed of a sample of JDs reviewed by EPA Region 8 and their outcomes in terms of aquatic resources that were considered non-jurisdictional. An analysis of stream types and characteristics across the region using available digital spatial analysis tools was performed. A subset of finalized JDs issued by COE was reviewed to analyze the scientific information used to evaluate connectivity to downstream waters

  14. Estratégias na suplementação de vacas leiteiras no semi-árido do Brasil Strategies for the supplementation of dairy cows in the Brazilian semi-arid

    Directory of Open Access Journals (Sweden)

    Marcelo de Andrade Ferreira

    2009-07-01

    Full Text Available A região semi-árida do Brasil prolonga-se por uma área de 928 km² abrangendo uma parte do norte dos estados de Minas Gerais e Espírito Santo, os sertões da Bahia, Sergipe, Alagoas, Pernambuco, Paraíba, Rio Grande do Norte, Ceará e Piauí e mais 45 municípios do sudeste do Maranhão. A população é predominantemente rural e a ocupação principal de sua força de trabalho é a agropecuária. A pecuária leiteira aparece como uma das poucas opções nas regiões semi-áridas, principalmente no nordeste do Brasil, onde a alimentação dos rebanhos fundamenta-se na utilização de forrageiras cultivadas e no uso da vegetação nativa, predominantemente a caatinga, aspecto que imprime características estacionais à produção nesta região. A escassez e irregularidade acentuada na distribuição de chuvas, tanto no tempo quanto no espaço, com a ocorrência de longos períodos de estiagem, praticamente, determina a obrigatoriedade de suplementação de vacas leiteiras nos sistemas de produções em regiões semi-áridas do Brasil.Desta forma, a suplementação tem se baseado na utilização de recursos forrageiros adaptados à seca, co- produtos e resíduos da agroindústria local e em alimentos concentrados. Algumas alternativas têm sido utilizadas pelos produtores na tentativa de reduzir custos sem perder produtividade nos períodos de estiagem. Para superar as adversidades alguns sistemas de produção têm sido propostos como o CBL (Caatinga-buffel-leucena e o Sistema Glória. Além desses sistemas mencionados anteriormente, merecem destaque a utilização de co-produtos agroindustriais, restos de cultura, além de forrageiras nativas e adaptadas. Neste aspecto, a palma forrageira (Opuntia fícus indica- Mill merece atenção especial pela sua grande adaptação, valor nutritivo e produtividade.The Brazilian semi-arid region has 928 km² ranging from the northern portion of Minas Gerais and Espirito Santo States, the semi-arid lands

  15. Analysis of drought events in a North Africa semi-arid region, Using SPOT-VEGETATION and C band scatterometer satellite Data

    Science.gov (United States)

    Zribi, M.; Amri, R.; Lili-Chabaane, Z.; Wagner, W.; Hasenauer, S.; Duchemin, B.; Boulet, G.; Mougenot, B.

    2012-04-01

    In semi-arid regions, and northern Africa in particular, the scarcity of rainfall and the occurrence of long periods of drought, represent one of the main environmental factors having a negative effect on agricultural productivity. This is the case in Central Tunisia, where the monitoring of agricultural and water resources is of prime importance. Vegetation cover and soil moisture are key parameters in this objective. Remote sensing has shown in the last decades a high potential to estimate these surface parameters. This study is based on two satellite products: SPOT-VEGETATION NDVI data and ERS and ASCAT/METOP moisture products proposed by Vienna University of Technology (TU Wien) (Wagner et al., 1999). A validation of soil moisture products is realized over the studied site using ground measurements (Thetaprobe continuous measurements), inter-comparison with other satellite products and precipitation levels. Based on long time series of satellite products, two anomaly indices have been proposed. In order to estimate the state of stress of the vegetation cover, an index referred to as the Vegetation Anomaly Index (VAI) is proposed from SPOT-VGT time series. A positive VAI indicates good vegetation dynamics, whereas a negative VAI indicates the presence of vegetation stress. This index is highly correlated to precipitation, and is found to have a maximum correlation with the 4-month cumulative precipitation (CP3). The VAI index can be operationally applied in order to estimate quantitatively the effect of drought on vegetation cover. Based on SWI (Soil Water Index) products, representing root-zone soil moisture content in the first meter of the soil, we propose a simple Moisture Anomaly Index, which can provide a quantitative visualization of drought periods. This index is compared with and validated, using the SPI precipitation index. A high degree of correlation is observed between the two indices. The Moisture Anomaly Index could be a very useful tool in

  16. Dynamics and sources of soil organic C following afforestation of croplands with poplar in a semi-arid region in northeast China.

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    Ya-Lin Hu

    Full Text Available Afforestation of former croplands has been proposed as a promising way to mitigate rising atmospheric CO2 concentration in view of the commitment to the Kyoto Protocol. Central to this C sequestration is the dynamics of soil organic C (SOC storage and stability with the development of afforested plantations. Our previous study showed that SOC storage was not changed after afforestation except for the 0-10 cm layer in a semi-arid region of Keerqin Sandy Lands, northeast China. In this study, soil organic C was further separated into light and heavy fractions using the density fractionation method, and their organic C concentration and (13C signature were analyzed to investigate the turnover of old vs. new SOC in the afforested soils. Surface layer (0-10 cm soil samples were collected from 14 paired plots of poplar (Populus × xiaozhuanica W. Y. Hsu & Liang plantations with different stand basal areas (the sum of the cross-sectional area of all live trees in a stand, ranging from 0.2 to 32.6 m(2 ha(-1, and reference maize (Zea mays L. croplands at the same sites as our previous study. Soil ΔC stocks (ΔC refers to the difference in SOC content between a poplar plantation and the paired cropland in bulk soil and light fraction were positively correlated with stand basal area (R (2 = 0.48, p<0.01 and R (2 = 0.40, p = 0.02, respectively, but not for the heavy fraction. SOCcrop (SOC derived from crops contents in the light and heavy fractions in poplar plantations were significantly lower as compared with SOC contents in croplands, but tree-derived C in bulk soil, light and heavy fraction pools increased gradually with increasing stand basal area after afforestation. Our study indicated that cropland afforestation could sequester new C derived from trees into surface mineral soil, but did not enhance the stability of SOC due to a fast turnover of SOC in this semi-arid region.

  17. Integrated Surface and Ground Water modeling of a tank cascaded sub basin using physically based model in a semi-arid region

    Science.gov (United States)

    Ilampooranan, I.; Muthiah, K.; Athikesavan, R.

    2013-05-01

    Hydrological Modeling of tank (small reservoirs) cascaded sub-basin of a semi-arid region is a complex process. Physically based approach can simulate the various processes in surface, unsaturated and saturated ground water zones of such sub basin in an integrated manner. The objectives of the study are (i) to characterize the study area to replicate the physical conditions of surface and saturated zones (ii) to carryout overland flow routing of a tank cascaded basin using physically based modular approach (iii) To simulate the ground water levels in the unconfined aquifer (iv) to study the surface and groundwater dynamics on incorporation of tank cascades in the integrated model. An integrated, physically based model MIKE 11 & MIKE SHE was applied to study the hydrological processes of a tank cascaded semi-arid basin in which flow through tanks were modeled using MIKE 11 and coupled with MIKE SHE in-order to best represent the surface water dynamics in a distributed manner. Sindapalli Uppodai sub-basin, Southern Tamilnadu, India is chosen as study area. There are 15 tanks connected in series forming a tank cascade. Other tanks and depressions in the sub basin are also considered for the study and their effectiveness were analysed. DEM was obtained from SRTM data. The maps such as drainage network, land use and soil are prepared. Soil sampling was carried out. The time series data of rainfall and climate parameters are given as input. The characterization of unconfined aquifer formation was done by Geo-Resistivity survey. 71 observation and pumping wells are monitored within and periphery of sub basin which are used for calibration of the model. The flow routing over the land is done by MIKE SHE's Overland Flow Module, using the diffusive wave approximation of the Saint Venant equation. The hydrograph of routed runoff from the tank cascaded catchment was obtained. The spatial and temporal variation of hydraulic head of the saturated ground water zone is simulated

  18. Water and Carbon Fluxes in a Semi-Arid Region Floodplain: Multiple Approaches to Constrain Estimates of Seasonal- and Depth Dependent Fluxes at Rifle, Colorado

    Science.gov (United States)

    Tokunaga, T. K.; Wan, J.; Dong, W.; Kim, Y.; Williams, K. H.; Conrad, M. E.; Christensen, J. N.; Bill, M.; Faybishenko, B.; Hobson, C.; Dayvault, R.; Long, P. E.; Hubbard, S. S.

    2014-12-01

    The importance of floodplains as links between watersheds and rivers highlights the need to understand water and carbon fluxes within floodplain profiles, from their surface soil, through the vadose zone and underlying groundwater. Here, we present results of field and laboratory measurements conducted to quantify fluxes at a remediated uranium/vanadium mill tailings site on a floodplain at Rifle, Colorado. This semi-arid site has a vegetated, locally derived fill soil that replaced the original milling-contaminated soil to a depth of about 1.5 m. The fill soil overlies about 4.5 m of native sandy and cobbly alluvium containing the shallow aquifer. The aquifer generally drains into the Colorado River and is underlain by low permeability Wasatch Formation shale. Within this system, key issues being investigated include water and carbon fluxes between the vadose zone and aquifer, and CO2 fluxes through the vadose zone soil out to the atmosphere. Magnitudes of these fluxes are typically low, thus challenging to measure, yet increasingly important to quantify given the expansion of arid and semi-arid regions under changing climate. The results of field investigations demonstrated that the annual water table rise and fall are driven by snowmelt runoff into the Colorado River in late spring to early summer. Tensiometer data indicate that net recharge from the deeper part of the vadose zone into groundwater occurs later in summer, after water table decline. The effectiveness of summer evapotranspiration in limiting groundwater recharge is reflected in water potentials decreasing to as low as -3 MPa within the upper 1.5 m of the vadose zone. Examination of the historical precipitation record further indicates that net recharge only occurs in years with above-average precipitation during winter and spring. These short intervals of net recharge also facilitate C transport into groundwater because of higher organic C concentrations in the vadose zone. Fluxes of CO2 measured

  19. Diversity and structure of microcrustacean assemblages (Cladocera and Copepoda and limnological variability in perennial and intermittent pools in a semi-arid region, Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Nadson R. Simões

    2011-12-01

    Full Text Available Temporary wetlands undergo recurrent drought due to the scarcity of water, which disrupts the hydrological connectivity with adjacent aquatic systems. However, some environments retain water for longer periods, allowing greater persistence of the community. The current study evaluated differences in the microcrustacean assemblages and limnological variability between perennial and intermittent pools in a semi-arid region of Brazil. The abiotic features (water temperature, pH, total alkalinity, electrical conductivity and depth of intermittent pools were affected more than perennial pools due to loss of water volume. This may have contributed to a higher average richness and diversity index in some intermittent pools and differences in the structure of the assemblages. The lowest species richness and diversity were recorded where physical factors, such as a large quantity of suspended solids and variability in the electrical conductivity of the water and pH, make the environment unsuitable for these organisms. These results suggest that community development in intermittent pools is interrupted by the dry season; when the water returns, due to rainfall or rising groundwater, each pond undergoes a different process of colonization. In these circumstances, the biological importance of temporary aquatic environments is clear, since such pools provide shelters and have an important role in the maintenance of the regional diversity of aquatic environments.

  20. Screening of efficient arbuscular mycorrhizal fungi for Azadirachta indica under nursery condition: a step towards afforestation of semi-arid region of western India

    Directory of Open Access Journals (Sweden)

    K. Banerjee

    2013-01-01

    Full Text Available To optimize nursery practices for efficient plant production procedures and to keep up to the ever growing demand of seedlings, identification of the most suitable species of arbuscular mycorrhizal fungi (AMF, specific for a given tree species, is clearly a necessary task. Sixty days old seedlings of Neem (Azadirachta indica A. Juss raised in root trainers were inoculated with six species of AMF and a mixed inoculum (consortia and kept in green house. Performances of the treatments on this tree species were evaluated in terms of growth parameters like plant height shoot collar diameter, biomass and phosphorous uptake capabilities. Significant and varied increase in the growth parameters and phosphorous uptake was observed for most of the AMF species against control. Consortia culture was found to be the best suited AMF treatment for A.indica, while Glomus intraradices and Glomus mosseae were the best performing single species cultures. It is the first time in the state of Gujarat that a wide variety of AMF species, isolated from the typical semi-arid region of western India, were tested for the best growth performance with one of the most important tree species for the concerned region.

  1. Evaluation of hydrological balance and its variability in arid and semi-arid regions of Eurasia from ECMWF 15 year reanalysis

    Science.gov (United States)

    Yatagai, Akiyo

    2003-10-01

    Hydrometeorological cycles over arid and semi-arid regions in mid-latitude Eurasia (the Silk Road region) were investigated using meteorological reanalysis data for the period 1979-93, available from the European Centre for Medium-range Weather Forecasts (ECMWF).Results show that seasonal changes of moisture balance in Turkey and central Asia, hereafter referred to as the western region, differ from those in the Taklimakan Desert and Loess Plateau, hereafter referred to as the eastern region. Here, we equate evaporation minus precipitation with the divergence field of the vertically integrated water vapour flux. In the western region, precipitation and positive convergence C of moisture primarily occurs during October-March. In contrast, the eastern region receives precipitation and has its positive C occurring during June-August. As a result, the eastern region has nearly simultaneous seasonal peaks in precipitation P and evapotranspiration E, whereas the western region has minimum P and maximum E in summer.The main annual moisture route for the Silk Road region is from the west to east; however, moisture also comes from the north in July. Over Turkey, moisture arrives from the west and south. In central Asia, however, most of the moisture comes from the west, the convergence peaks in March, and moisture from the south and west is also greater during this month. In the Loess Plateau, moisture enters from the west, the north, and the south, and exits to the east. In July, the peak precipitation and convergence season, all moisture flows are greater for the entire region, and a large influx of moisture from the south occurs during the summer season. The moisture from the south, the monsoonal flow, has a large interannual variability. Copyright

  2. Identifying and managing risk factors for salt-affected soils: a case study in a semi-arid region in China.

    Science.gov (United States)

    Zhou, De; Xu, Jianchun; Wang, Li; Lin, Zhulu; Liu, Liming

    2015-07-01

    Soil salinization and desalinization are complex processes caused by natural conditions and human-induced risk factors. Conventional salinity risk identification and management methods have limitations in spatial data analysis and often provide an inadequate description of the problem. The objectives of this study were to identify controllable risk factors, to provide response measures, and to design management strategies for salt-affected soils. We proposed to integrate spatial autoregressive (SAR) model, multi-attribute decision making (MADM), and analytic hierarchy process (AHP) for these purposes. Our proposed method was demonstrated through a case study of managing soil salinization in a semi-arid region in China. The results clearly indicated that the SAR model is superior to the OLS model in terms of risk factor identification. These factors include groundwater salinity, paddy area, corn area, aquaculture (i.e., ponds and lakes) area, distance to drainage ditches and irrigation channels, organic fertilizer input, and cropping index, among which the factors related to human land use activities are dominant risk factors that drive the soil salinization processes. We also showed that ecological irrigation and sustainable land use are acceptable strategies for soil salinity management. PMID:26063060

  3. Identifying and managing risk factors for salt-affected soils: a case study in a semi-arid region in China.

    Science.gov (United States)

    Zhou, De; Xu, Jianchun; Wang, Li; Lin, Zhulu; Liu, Liming

    2015-07-01

    Soil salinization and desalinization are complex processes caused by natural conditions and human-induced risk factors. Conventional salinity risk identification and management methods have limitations in spatial data analysis and often provide an inadequate description of the problem. The objectives of this study were to identify controllable risk factors, to provide response measures, and to design management strategies for salt-affected soils. We proposed to integrate spatial autoregressive (SAR) model, multi-attribute decision making (MADM), and analytic hierarchy process (AHP) for these purposes. Our proposed method was demonstrated through a case study of managing soil salinization in a semi-arid region in China. The results clearly indicated that the SAR model is superior to the OLS model in terms of risk factor identification. These factors include groundwater salinity, paddy area, corn area, aquaculture (i.e., ponds and lakes) area, distance to drainage ditches and irrigation channels, organic fertilizer input, and cropping index, among which the factors related to human land use activities are dominant risk factors that drive the soil salinization processes. We also showed that ecological irrigation and sustainable land use are acceptable strategies for soil salinity management.

  4. Hydraulic parameters estimation by using an approach based on vertical electrical soundings (VES) in the semi-arid Khanasser valley region, Syria

    Science.gov (United States)

    Asfahani, Jamal

    2016-05-01

    A new alternative approach based on using Vertical electrical sounding (VES) technique is proposed for computing the hydraulic conductivity K of an aquifer. The approach takes only the salinity of the groundwater into consideration. VES measurements in the locations, where available water samples exist, are required in such an approach, in order to calibrate and establish empirical relationships between transverse resistance Dar-Zarrouck TR parameter and modified transverse resistance MTR, and between MTR and transmissivity T. Those relationships are thereafter used to extrapolate the transmissivity even in the VES points where no water samples exist. This approach is tested and practiced in the Khanasser valley, Northern Syria, where the hydraulic conductivity of the Quaternary aquifer is computed. An acceptable agreement is found between the hydraulic conductivity values obtained by the proposed approach and those obtained by the pumping test which range between 0.864 and 8.64 m/day (10-5 and 10-4 m/s). The Quaternary aquifer transmissivity of the Khanasser Valley, has been characterized by using this approach and by adapting the MTR parameter. The transmissivity varies between a minimum of 79 m2/day and a maximum of 814 m2/day, with an average of 283 m2/day and a standard deviation of 145 m2/day. The easy and inexpensive approach proposed in this paper can be applied in other semi arid regions.

  5. An empirical method for peak discharge prediction in ungauged arid and semi-arid region catchments based on morphological parameters and SCS curve number

    Science.gov (United States)

    El-Hames, A. S.

    2012-08-01

    SummaryAn empirical method that utilizes the SCS curve number and catchment characteristics has been developed to help in the prediction of peak discharge in ungauged arid and semi-arid region catchments. The morphological factors that were found to control peak discharge are catchment area and slope, and main channel length. The hydrological controls, however, are the effective rainfall that reflects the antecedent wetness condition of the catchment which was calculated from the determined catchment curve number (CN). The data incorporated in the developed method are easy to obtain from satellite images and by utilizing GIS techniques without the need for intensive field visits or relying on historical runoff records. The developed method has been calibrated and validated against 76 rainfall-runoff events from six different countries around the world and it has shown encouraging performance when compared with observed peak discharge data or the results from other models. The developed method performs very well with catchments larger than 45 km2 with coefficient of correlation of 0.92. However, for catchments with areas less than 45 km2 the obtained coefficient of correlation was 0.67. Also, the developed method performs very well with either event-based or return-period-based peak discharge prediction and it can be considered a good alternative to the rational method.

  6. Spatial and temporal analysis of the drought vulnerability and risks over eight decades in a semi-arid region (Tensift basin: Morocco)

    Science.gov (United States)

    Fniguire, Fatima; Laftouhi, Nour-Eddine; Saidi, Mohamed Elmehdi; Zamrane, Zineb; El Himer, Hicham; Khalil, Nourddine

    2016-08-01

    In the last few decades, drought has become a chronic phenomenon in Morocco. It began at the end of the 1970s and continued to the late 2000s. In the present study, hydrometeorological data sets, Standardized Precipitation Index method, and non-parametric tests were used to recognize the frequency and the severity of drought events during the period between 1929 and 2010. The Standardized Precipitation Index showed significant inter-annual fluctuation and evolution of rainfall amounts representing wet cycles (i.e., before 1975) followed by a long period of drought between 1975 and 2004. The inter-annual variability of rainfall is accompanied by shifts of stationarity in the rainfall series. The statistical test of Pettitt, Bayesian method of Lee and Heghinian, Buishand procedure, and Hubert test revealed shifts around the mid 70s. After this period, a deficit of rainfall (with a maximum value of -30 %) was registered. The probabilities of monthly Standardized Precipitation Index values were normal to below normal during the last 40 years. In fact, the increase of drought risk may be resulted from the increase of frequency and severity of meteorological drought. The proposed Standardized Precipitation Index method and non-parametric tests yielded reasonable and satisfactory results for Morocco. Therefore, this approach could be successfully applied to other semi-arid, dry, sub-humid, or semi-humid regions worldwide, where rainfall series are showing high seasonality and year-to-year variability.

  7. Identification of spatiotemporal patterns of biophysical droughts in semi-arid region – a case study of the Karkheh river basin in Iran

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    B. Kamali

    2015-06-01

    Full Text Available This study aims at identifying historical patterns of meteorological, hydrological, and agricultural (inclusively biophysical droughts in the Karkheh River Basin (KRB, one of the nine benchmark watersheds of the CGIAR Challenge Program on Water and Food. Standardized precipitation index (SPI, standardized runoff index (SRI, and soil moisture deficit index (SMDI were used to represent the above three types of droughts, respectively. The three drought indices were compared across temporal and spatial dimensions. Variables required for calculating the indices were obtained from the Soil and Water Assessment Tool (SWAT constructed for the region. The model was calibrated based on monthly runoff and yearly wheat yield using the Sequential Uncertainty Fitting (SUFI-2 algorithm. Five meteorological drought events were identified in the studied period (1980–2004, of which four corresponded with the hydrological droughts with 1–3 month lag. The meteorological droughts corresponded well with the agricultural droughts during dry months (May–August, while the latter lasted for a longer period of time. Analysis of drought patterns showed that southern parts of the catchment were more prone to agricultural drought, while less influenced by hydrological drought. Our analyses highlighted the necessity for monitoring all three aspects of drought for a more effective watershed management. The analysis on different types of droughts in this study provides a framework for assessing their possible impacts under future climate change in semi-arid areas.

  8. The problems of overexploitation of aquifers in semi-arid areas: the Murcia Region and the Segura Basin (South-east Spain case

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    T. Rodríguez-Estrella

    2012-05-01

    Full Text Available A general analysis of the problems arising from aquifer exploitation in semi-arid areas such as the Autonomous Region of Murcia, which belongs to the Segura Basin is presented, with particular reference to the Ascoy-Sopalmo aquifer, which is the most overexploited aquifer in Spain. It has suffered intense overabstraction over the last forty years, given renewable water resources of 2 Mm3 yr−1 and abstractions amounting to as much as 55 Mm3 yr−1. This has resulted in the drying of springs, continuous drawdown of water levels (5 m yr−1; piezometric drops (over 30 m in one year, as a consequence of it being a karstic aquifer; increase in pumping costs (elevating water from more than 320 m depth; abandoning of wells (45 reduced to 20, diminishing groundwater reserves, and deteriorating water quality (progressing from a mixed sodium bicarbonate-chloride facies to a sodium chloride one. This is a prime example of poor management with disastrous consequences. In this sense, a series of internal measures is proposed to alleviate the overexploitation of this aquifer and of the Segura Basin, with the aim of contributing to a sustainable future.

  9. Growth of seven perennial plant species adapted to the Brazilian Semi-Arid Crescimento de sete espécies vegetais perenes adaptadas ao Semi-Árido brasileiro

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    Paulo Sérgio Lima e Silva

    2007-12-01

    Full Text Available Measuring plant height (y and canopy diameter (x in trees may not be an easy task, but stem diameter (z can be more easily evaluated. This work's objective was two-fold: evaluate the growth of species adapted to the Brazilian Semi-Arid Region in the first two years of age, and obtain linear equations to estimate y and x from z, in those species. A random block design with four replications was employed. The values for x, z, and y were measured biannually from October/2003 to March/2005. Prosopis juliflora and Mimosa caesalpiniaefolia showed the highest stem diameter and plant height values, respectively, and both showed the highest canopy diameter. In the equations to estimate plant height from the stem diameter the value of the coefficient of determination (R² ranged from 0.76 (Tamarindus indica and Leucaena leucocephala to 0.92 (Prosopis juliflora and Azadirachta indica. In the equations that allowed to estimate the crown diameter from the stem diameter the R² value ranged from 0.70 (Leucaena leucocephala to 0.92 (Azadirachta indica.A mensuração da altura da planta (y e do diâmetro da copa (x em árvores pode não ser tarefa fácil, mas o diâmetro do caule (z pode ser avaliado mais facilmente. Este trabalho teve por objetivos avaliar o crescimento de espécies adaptadas ao Semi-Árido brasileiro, nos primeiros dois anos de idade, e obter equações lineares para estimar y e x a partir de z, nessas espécies. Utilizou-se o delineamento de blocos ao acaso com quatro repetições. Os valores de x, z e y foram medidos semestralmente de outubro/2003 a março/2005. Prosopis juliflora e Mimosa caesalpiniaefolia apresentaram os maiores diâmetros do caule e altura da planta, respectivamente, e ambas apresentaram o maior diâmetro da copa. Nas equações para estimar a altura da planta a partir do diâmetro do caule, o valor do coeficiente de determinação (R² variou de 0,76 (Tamarindus indica and Leucaena leucocephala a 0,92 (Prosopis

  10. Rivers through time: historical changes in the riparian vegetation of the semi-arid, winter rainfall region of South Africa in response to climate and land use.

    Science.gov (United States)

    Hoffman, M Timm; Rohde, Richard Frederick

    2011-01-01

    This paper examines how the riparian vegetation of perennial and ephemeral rivers systems in the semi-arid, winter rainfall region of South Africa has changed over time. Using an environmental history approach we assess the extent of change in plant cover at 32 sites using repeat photographs that cover a time span of 36-113 years. The results indicate that in the majority of sites there has been a significant increase in cover of riparian vegetation in both the channel beds and adjacent floodplain environments. The most important species to have increased in cover across the region is Acacia karroo. We interpret the findings in the context of historical changes in climate and land use practices. Damage to riparian vegetation caused by mega-herbivores probably ceased sometime during the early 19th century as did scouring events related to large floods that occurred at regular intervals from the 15th to early 20th centuries. Extensive cutting of riparian vegetation for charcoal and firewood has also declined over the last 150 years. Changes in the grazing history as well as increased abstraction and dam building along perennial rivers in the region also account for some of the changes observed in riparian vegetation during the second half of the 20th century. Predictions of climate change related to global warming anticipate increased drought events with the subsequent loss of species and habitats in the study area. The evidence presented here suggests that an awareness of the region's historical ecology should be considered more carefully in the modelling and formulation of future climate change predictions as well as in the understanding of climate change impacts over time frames of decades and centuries.

  11. Individual Land Tenure and the Challenges of Sustainable Land Use and Management in a Semi-arid Region of China Individual Land Tenure and the Challenges of Sustainable Land Use and Management in a Semi-arid Region of China

    OpenAIRE

    Yongjun Zhao

    2010-01-01

    China’s farmland tenure, characterised by a household responsibility system (HRS) and collective landownership, has contributed to the continuation of poverty and natural resource deterioration in semiarid regions. Incongruent with local ecological, social and political conditions, the HRS has been linked to rising social and political tensions. Drawing on ethnographic research in Guyuan County, North China, this paper provides peasants’ experiences of and views on the land issue and examines...

  12. How To Assess The Future Tree-Cover Potential For Reforestation Planning In Semi-Arid Regions? An Attempt Using The Vegetation Model ORCHIDEE

    Science.gov (United States)

    Rajaud, A.; De Noblet-Ducoudré, N.

    2015-12-01

    More and more reforestation projects are undertaken at local to continental scales to fight desertification, to address development challenges, and to improve local living conditions in tropical semi-arid regions. These regions are very sensitive to climatic changes and the potential for maintaining tree-covers will be altered in the next decades. Therefore, reforestation planning needs predicting the future "climatic tree-cover potential": the optimum tree-fraction sustainable in future climatic states. Global circulation models projections provide possible future climatologies for the 21st century. These can be used at the global scale to force a land-surface model, which in turn simulates the vegetation development under these conditions. The tree cover leading to an optimum development may then be identified. We propose here to run a state-of-the-art model and to assess the span and the relevance of the answers that can be obtained for reforestation planning. The ORCHIDEE vegetation model is chosen here to allow a multi-criteria evaluation of the optimum cover, as it returns surface climate state variables as well as vegetation functioning and biomass products. It is forced with global climate data (WFDEI and CRU) for the 20th century and models projections (CMIP5 outputs) for the 21st century. At the grid-cell resolution of the forcing climate data, tree-covers ranging from 0 to 100% are successively prescribed. A set of indicators is then derived from the model outputs, meant for modulating reforestation strategies according to the regional priorities (e.g. maximize the biomass production or decrease the surface air temperature). The choice of indicators and the relevance of the final answers provided will be collectively assessed by the climate scientists and reforestation project management experts from the KINOME social enterprise (http://en.kinome.fr). Such feedback will point towards the model most urging needs for improvement.

  13. Ele não quer com camisinha e eu quero me prevenir: exposição de adolescentes do sexo feminino às DST/aids no semi-árido nordestino He does not want it with condom and I want to protect myself: exposure of female adolescents to STD/AIDS in the semi-arid region of the Brazilian northeast

    Directory of Open Access Journals (Sweden)

    Juliana Sampaio

    2011-03-01

    semi-arid region located in the Northeast of Brazil. The applied methodology was supported by the qualitative approach in health, and Discursive Practices and Production of Meaning (Spink, 2004; Medrado and Spink, 1999 were used as the theoretical and methodological model. Three methodological strategies were used for data collection: 1,024 hours of participant observation, 72 semi-structured interviews and 36 focus groups, comprising two groups of actors: 72 professionals of 8 health teams and 360 adolescents of both sexes. From the analysis of results it was possible to verify that the Northeastern reality is permeated by characteristics that make the women vulnerable to STD / AIDS, such as: a low educational levels; b unequal gender relations; c absence of a prevention policy targeted at teenagers; d lack of bonds between health professionals and the population; e the frequent understanding of health services as a space exclusively for women. In light of this context, we point to the need of policies of integral health care to adolescents that approach the sexual and reproductive rights in a gender perspective for the effective prevention of STD / AIDS, exerting a direct impact on improving the quality of their lives.

  14. Analysis of drought events in a Mediterranean semi-arid region, Using SPOT-VGT and TERRA-MODIS satellite products

    Science.gov (United States)

    Zribi, Mehrez; Dridi, Ghofrane; Amri, Rim; Lili-Chabaane, Zohra

    2015-04-01

    In semi-arid regions, and northern Africa in particular, the scarcity of rainfall and the occurrence of long periods of drought, represent one of the main environmental factors having a negative effect on agricultural productivity. This is the case in Central Tunisia, where the monitoring of agricultural and water resources is of prime importance. Vegetation cover is a key parameter to analyse this problem. Remote sensing has shown in the last decades a high potential to estimate these surface parameters. This study is based on two satellite products: SPOT-VGT (1998-2012) and TERRA-MODIS (2001-2012) NDVI products. They are used to study the dynamics of vegetation and land use. Different behaviors linked to drought periods have been observed. A strong agreement is observed between products proposed by the two sensors. Low spatial resolution SPOT-VGT and TERRA-MODIS NDVI images were used to map the land into three characteristic classes: olive trees, annual agriculture and pastures. An analysis of vegetation behaviour for dry years is proposed using the Windowed Fourier Transform (WTF). The Fourier Transform is able to analyze the frequency content of a signal in the time domain by decomposing the signal as the superposition of sine and cosine basis functions. Analysis for annual agricultural areas demonstrates a combined effect between climate and farmers behaviours. In these areas, bare soils show a high increasing for drought years. Highest percent of bare soil is retrieved with TERRA-MODIS than with SPOT-VGT. This could be explained by the spatial resolution of the two sensors. The temporal series of optical images are finally used to calculate a drought index, namely the VAI (Vegetation Anomaly Index), on the plain of Kairouan (Amri et al., 2011). This index shows a high correlation with precipitation statistics.

  15. Combining hydrology and mosquito population models to identify the drivers of Rift Valley fever emergence in semi-arid regions of West Africa.

    Directory of Open Access Journals (Sweden)

    Valérie Soti

    Full Text Available BACKGROUND: Rift Valley fever (RVF is a vector-borne viral zoonosis of increasing global importance. RVF virus (RVFV is transmitted either through exposure to infected animals or through bites from different species of infected mosquitoes, mainly of Aedes and Culex genera. These mosquitoes are very sensitive to environmental conditions, which may determine their presence, biology, and abundance. In East Africa, RVF outbreaks are known to be closely associated with heavy rainfall events, unlike in the semi-arid regions of West Africa where the drivers of RVF emergence remain poorly understood. The assumed importance of temporary ponds and rainfall temporal distribution therefore needs to be investigated. METHODOLOGY/PRINCIPAL FINDINGS: A hydrological model is combined with a mosquito population model to predict the abundance of the two main mosquito species (Aedes vexans and Culex poicilipes involved in RVFV transmission in Senegal. The study area is an agropastoral zone located in the Ferlo Valley, characterized by a dense network of temporary water ponds which constitute mosquito breeding sites. The hydrological model uses daily rainfall as input to simulate variations of pond surface areas. The mosquito population model is mechanistic, considers both aquatic and adult stages and is driven by pond dynamics. Once validated using hydrological and entomological field data, the model was used to simulate the abundance dynamics of the two mosquito species over a 43-year period (1961-2003. We analysed the predicted dynamics of mosquito populations with regards to the years of main outbreaks. The results showed that the main RVF outbreaks occurred during years with simultaneous high abundances of both species. CONCLUSION/SIGNIFICANCE: Our study provides for the first time a mechanistic insight on RVFV transmission in West Africa. It highlights the complementary roles of Aedes vexans and Culex poicilipes mosquitoes in virus transmission, and recommends

  16. Influence of Different Fertilization on moisture Characteristics of Black Soil under Drought Year in Semi-arid Regions in Northeast China

    Science.gov (United States)

    Han, X.; Zou, W.

    2009-04-01

    Water was a mainly limited factor for crop yield in rain-feed agriculture of semi-arid region. Whereas, fertilization can regulate capability of soil water supply. Therefore, field experiments were set up at the National Field Research Station of Agroecosystem of Chinese Academy of Science in Hailun County, Heilongjiang Province, China, in 1990, including three fertilizer treatments: no fertilizer (NF), applying chemical nitrogen and phosphorus fertilizer (NP), applying chemical nitrogen and phosphorus fertilizer plus organic manure (NPM). The experiments were carried out to investigate the effects of different fertilization on soil water supply, water consumption of maize, water use efficiency under drought year. The results showed that rainfall didn't satisfy water need of maize in drought year, the deficient water was compensated by soil water reservoir, Fertilizer application, especially organic manure application, can improve the capability of soil water supply, the ratio between soil water supply and water consumption of NF, NP, NPM were 22.23%, 23.58% and 25.99% in the whole development period of maize, respectively. Total water consumption and water consumption rate of maize were significantly impacted by different fertilization and increased with application of chemical fertilizer and organic manure, results showed total water consumption of maize were 485.82mm, 494.83mm and 509.91mm for NF, NP and NPM, respectively, while water consumption rates were 3.18mm/d, 3.23mm/d and 3.33mm/d for NF, NP and NPM, respectively. The effect of fertilizer application on water use efficiency was in the order of NPM > NP > NF. From the study, it can be concluded that soil water supply buffered and regulated soil water condition, and played an important role on guaranteeing crop yield; fertilizer application, can enhance soil water supply, increase crop yield and water use efficiency, especially organic manure application.

  17. Index-based assessment of agricultural drought in a semi-arid region of Inner Mongolia, China

    Institute of Scientific and Technical Information of China (English)

    Rui; LI; Atsushi; TSUNEKAWA; Mitsuru; TSUBO

    2014-01-01

    Agricultural drought is a type of natural disaster that seriously impacts food security.Because the relationships among short-term rainfall,soil moisture,and crop growth are complex,accurate identification of a drought situation is difficult.In this study,using a conceptual model based on the relationship between water deficit and crop yield reduction,we evaluated the drought process in a typical rainfed agricultural region,Hailar county in Inner Mongolia autonomous region,China.To quantify drought,we used the precipitation-based Standardized Precipitation Index(SPI),the soil moisture-based Crop Moisture Index(CMI),as well as the Normalized Difference Vegetation Index(NDVI).Correlation analysis was conducted to examine the relationships between dekad-scale drought indices during the growing season(May–September)and final yield,according to data collection from 2000 to 2010.The results show that crop yield has positive relationships with CMI from mid-June to mid-July and with the NDVI anomaly throughout July,but no correlation with SPI.Further analysis of the relationship between the two drought indices shows that the NDVI anomaly responds to CMI with a lag of 1 dekad,particularly in July.To examine the feasibility of employing these indices for monitoring the drought process at a dekad time scale,a detailed drought assessment was carried out for selected drought years.The results confirm that the soil moisture-based vegetation indices in the late vegetative to early reproductive growth stages can be used to detect agricultural drought in the study area.Therefore,the framework of the conceptual model developed for drought monitoring can be employed to support drought mitigation in the rainfed agricultural region of Northern China.

  18. Index-based assessment of agricultural drought in a semi-arid region of Inner Mongolia, China

    Institute of Scientific and Technical Information of China (English)

    Rui LI; Atsushi TSUNEKAWA; Mitsuru TSUBO

    2014-01-01

    Agricultural drought is a type of natural disaster that seriously impacts food security. Because the rela-tionships among short-term rainfall, soil moisture, and crop growth are complex, accurate identification of a drought situation is difficult. In this study, using a conceptual model based on the relationship between water deficit and crop yield reduction, we evaluated the drought process in a typical rainfed agricultural region, Hailar county in Inner Mongolia autonomous region, China. To quantify drought, we used the precipitation-based Standardized Precipita-tion Index (SPI), the soil moisture-based Crop Moisture Index (CMI), as well as the Normalized Difference Vegeta-tion Index (NDVI). Correlation analysis was conducted to examine the relationships between dekad-scale drought indices during the growing season (May-September) and final yield, according to data collection from 2000 to 2010. The results show that crop yield has positive relationships with CMI from mid-June to mid-July and with the NDVI anomaly throughout July, but no correlation with SPI. Further analysis of the relationship between the two drought indices shows that the NDVI anomaly responds to CMI with a lag of 1 dekad, particularly in July. To examine the feasibility of employing these indices for monitoring the drought process at a dekad time scale, a detailed drought assessment was carried out for selected drought years. The results confirm that the soil moisture-based vegetation indices in the late vegetative to early reproductive growth stages can be used to detect agricultural drought in the study area. Therefore, the framework of the conceptual model developed for drought monitoring can be employed to support drought mitigation in the rainfed agricultural region of Northern China.

  19. LAS在西北半干旱地区的观测分析%Large Aperture Scintillometers(LAS)Observation in Semi-arid Regions of Northwestern China

    Institute of Scientific and Technical Information of China (English)

    黄山; 张文煜; 左洪超; 刘欣; 史永义

    2011-01-01

    In this paper, sensible heat flux in semi-arid region of northwestern China were calculated and analyzed by use of the observation data of Large Aperture Scintillometers (LAS) recorded per 30 minutes, the temperature, pressure data, and the observation data by Eddy Covariance System at Lanzhou University Semi-arid Climate and Environment Observatory during summer and winter of 2007.The values of the sensible heat flux in summer were bigger than that in winter, and there was a lag of peak value on diurnal variation curve in winter; at the similar weather conditions, the fluctuation of sensible flux in summer was bigger than that in winter.Weather condition had a great impact on the observations of LAS, the values of the sensible heat flux in sunny days were higher than that in cloudy days at the same season.Compared with sensible heat flux observed by Eddy Covariance System, the sensible heat flux measured by LAS was a little larger, but the values by the two methods showed a good agreement, and the correlation coefficient in summer was 0.95, and it was 0.98 in winter.%利用兰州大学半干旱气候与环境观测站2007年夏冬两季LAS观测数据.结合观测站气温、气压及同期的涡动相关仪30 min时间间隔的观测数据,计算分析了西北半干旱地区显热通量的变化特征,并将LAS所测结果与涡动相关仪的测量结果进行了对比分析.结果表明,在西北半干旱地区.夏季的显热通量值整体大于冬季,冬季显热通量的日变化峰值较夏季有明显的滞后性;在类似的天气状况下,夏季测得显热通量的波动要大于冬季;天气状况对LAS的观测结果有着很大的影响,在同一季节晴天显热通量较大,阴天较小;LAS测得显热通量H的值较涡动相关所得H值略微偏大.但LAS与涡动相关仪测得的显热通量有很好的符合性,复季相关系数为0.95,冬季相关系数为0.98.

  20. Proposal for regional sustainable development in semi-arid promoted by agents of the electric sector; Proposta de desenvolvimento regional sustentavel no semi-arido promovido por agente do setor eletrico

    Energy Technology Data Exchange (ETDEWEB)

    Polizel, L.H.; Tahan, C.M.V.; Pelegrini, M.A.; Soares, B.F. [Universidade de Sao Paulo (ENERQ/USP), SP (Brazil). Centro de Estudo em Regulacao e Qualidade de Energia; Takeno, H.K. [Companhia Energetica de Petrolina (CEP), PE (Brazil); Silva, O.C. da; Monteiro, B.; Velazquez, S.M.S.G. [Universidade de Sao Paulo (CENBIO/USP), SP (Brazil). Centro Nacional de Referencia em Biomassa; Drumond, M.A.

    2006-07-01

    This paper shows a thoroughly analysis of a biodiesel production model tailored to insert in the production chain communities near fossil fuels fired power plants located in the northeast Brazilian semi-arid. Such insertion would be conduced by the replacement of diesel by a diesel-bio diesel mixture, the last produced by local families. Among the factors analyzed on this small scale bio diesel production chain are: the castor oil extraction, transesterification process, efficiency and adequacy in power plants. The aim is to turn thermal power plants into a sustainable development vector, considering social, economical and environmental aspects such as local employment and income boost, settlement increase on rural areas, decrease of green house gases emissions, clean energy production and so forth. (author)

  1. Edge effect of the ecotone of wetland and arid grassland in a semi-arid region of China

    Institute of Scientific and Technical Information of China (English)

    Ruiping HOU; Rui LI; Kebin ZHANG; Yunfang LIU

    2008-01-01

    The edge effect of plant communities was investigated in a wetland-dry grassland ecosystem at the Siertan Wetland in Yanchi County, Ningxia Hui Autonomous Region, China. Four transects lines, with each about 1 km long, were established for a vegetation survey in July 2005, along biotope gradients in four direc-tions: east, northeast, west and northwest. The data was analyzed using TWINSPAN classification method. The vegetation in this wetland was classified into three vegeta-tion types: halophytic marsh vegetation, meadow vegeta-tion and grassland vegetation. Based on the calculation of the community structure indices, the edge effect was studied which revealed distinct differences among those three vegetation zones along each transect line. The eco-tone had high richness indices (R), a high diversity index (SW) and ecological dominance (SP). Evenness, as mea-sured by the index (E), was less apparent. From the four transect lines, it appears that the ecotone in the northeast-erly direction scored higher in each community structure indicator than any of the other directions and those towards the northwest were least. The variation in the edge effect between the different transect lines is caused by human disturbances and topographic uplift.

  2. Rain gauge network evaluation and optimal design using spatial correlation approach in arid and semi-arid regions of Iran

    Science.gov (United States)

    Nazaripour, Hamid; Mansouri Daneshvar, Mohammad Reza

    2016-06-01

    The present study is aimed at evaluation of a rain gauge network in order to optimize a network design. In this regard, point rainfall estimations were assessed using a spatial correlation approach in the Kerman region, Iran. This approach was implemented based on monthly rainfall data for existing 117 rain gauge stations in the study area. The results revealed that the regular arrangement of rain gauges could provide the reliable values for accurate rainfall estimation. Low density of rain gauge combined with the low rainfall values may result in strong increase of the interpolation errors. Based on the existing rain gauge network, the relative mean error of observed rainfalls (E a ) is less than 5 % over the study area. The spatial interpolation errors (E i ) were considered to optimize the design of rain gauge network at the confidence level of 85 %, where the mean errors were exhibited from 8.5 to 14 % in districts A and B, respectively. On this basis, about 46 locations were proposed for allocation of new stations. Therefore, it was suggested to relocate about 20 existing stations in order to achieve an accurate design.

  3. Emergy-based study on eco-economic system of arid and semi-arid region:a case of Gansu province,China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Taking Gansu province as a model case,this study provides an integrated analysis on the eco-economic system of arid and semi-arid region based on emergy synthesis theory. Through calculating the values of renewable emergy flow,non-renewable resources,imported emergy,exported emergy,waste emergy,and total emergy during the period of 1978-2007,the performance of Gansu eco-economic system was analyzed. The results indicated that the renewable emergy flow within the province basically remained steady state which was estimated at 2.99×1022 solar emjoules (sej) from 1978 to 2007. The imported emergy and exported emergy were estimated at 3.75×1017 sej and 2.99×1020 sej in 1978 and increased to 1.07×1022 sej and 1.44×1022 sej respectively in 2007. The nonrenewable emergy flow was estimated at 1.62×1022 sej and increased to 1.85×1023 sej,with annual growth rate of 8.7%,while the estimated total emergy was 4.58×1022 sej in 1978 and increased to 2.11×1023 sej in 2007,with annual growth rate of 5.41%. Our results indicate a deteriorate situation between economic development and environmental protection in the region. The rapid economic growth in the past thirty years was based on a great consumption of nonrenewable resource and caused continuous decrease in the capacity of sustainable development. The environmental loading ratio was 0.53 in 1978,increased to 6.06 in 2007,indicating a rapid degradation of the regional environment quality. We calculated that the actual population was 1.53 times the renewable resource population in 1978,increased to 7.06 times in 2007. During the period of 1978-2007,the emergy rose from 2.45×1015 sej/(capita·a) to 8.07×1015 sej/(capita·a). Our analysis revealed that the emergy density presented a trend of gradual increase,and then the emergy currency ratio in Gansu decreased from 7.08×1013 sej/Chinese Yuan to 7.82×1012 sej/Chinese Yuan.

  4. Conservation tillage of rainfed maize in semi-arid Zimbabwe: A review

    NARCIS (Netherlands)

    Nyakudya, I.W.; Stroosnijder, L.

    2015-01-01

    Food security in Sub-Saharan Africa, particularly in semi-arid tropics (41% of the region; 6 months of dry season) is threatened by droughts, dry spells and infertile soils. In Zimbabwe, 74% of smallholder farming areas are located in semi-arid areas mostly in areas with soils of low fertility and w

  5. 关于中国半干旱区一种生态农业模式的探讨%Discussion on an Eco-Agriculture Model in the Semi-Arid Region of China

    Institute of Scientific and Technical Information of China (English)

    张培栋

    2005-01-01

    The semi-arid region of China covers an area of 2.2 × 106km2. Water shortage in this region is the core but not the only one factor for the sustainable de ment of agriculture. Effective application of the energy and all kinds of resources and overall maintenance of the balance of ecological environment must be emphasized for sustainable development of the agriculture in the region. The extensive development of rural yard-economy is the only way to realize the intensive agricultural development there. A modelis developed on the basis of our studies in recent years.

  6. Larvicidal potential of wild mustard (Cleome viscosa) and gokhru (Tribulus terrestris) against mosquito vectors in the semi-arid region of Western Rajasthan.

    Science.gov (United States)

    Bansal, S K; Singh, Karam V; Sharma, Sapna

    2014-03-01

    effective as compared to the fruit extracts of T. terrestris indicating that active larvicidal principle may be present in the fruits of this plant species. The studywould be of great importance while formulating the control strategy, for vectors of malaria, dengue and lymphatic filariasis, based on alternative plant based insecticides in this semi-arid region. PMID:24665757

  7. Detection and differentiation of pollution in urban surface soils using magnetic properties in arid and semi-arid regions of northwestern China

    International Nuclear Information System (INIS)

    Increasing urbanization and industrialization over the world has caused many social and environmental problems, one of which drawing particular concern is the soil pollution and its ecological degradation. In this study, the efficiency of magnetic methods for detecting and discriminating contaminates in the arid and semi-arid regions of northwestern China was investigated. Topsoil samples from six typical cities (i.e. Karamay, Urumqi, Lanzhou, Yinchuan, Shizuishan and Wuhai) were collected and a systematic analysis of their magnetic properties was conducted. Results indicate that the topsoil samples from the six cities were all dominated by coarse low-coercivity magnetite. In addition, the average magnetite contents in the soils from Urumqi and Lanzhou were shown to be much higher than those from Karamay, Yinchuan, Shizuishan and Wuhai, and they also have relatively higher χlf and χfd% when compared with cities in eastern China. Moreover, specific and distinctive soil pollution signals were identified at each sampling site using the combined various magnetic data, reflecting distinct sources. Industrial and traffic-derived pollution was dominant in Urumqi and Lanzhou, in Yinchuan industrial progress was observed to be important with some places affected by vehicle emission, while Karamay, Shizuishan and Wuhai were relatively clean. The magnetic properties of these latter three cities are significantly affected by both anthropogenic pollution and local parent materials from the nearby Gobi desert. The differences in magnetic properties of topsoil samples affected by mixed industrial and simplex traffic emissions are not obvious, but significant differences exist in samples affected by simplex industrial/vehicle emissions and domestic pollution. The combined magnetic analyses thus provide a sensitive and powerful tool for classifying samples according to likely sources, and may even provide a valuable diagnostic tool for discriminating among different cities

  8. Evaluation of the SAFRAN-ISBA-RAPID hydrometeorological chain on a mountainous catchment in a semi-arid region. Case of the Rheraya (Marrakech, Morocco)

    Science.gov (United States)

    Szczypta, Camille; Gascoin, Simon; Habets, Florence; Saaidi, Amina; Berjamy, Brahim; Marchane, Ahmed; Boulet, Gilles; Hanich, Lahoucine; Jarlan, Lionel

    2015-04-01

    The water content of snow pack is an important resource for many watershed in semi-arid areas where downstream plains are dominated by irrigated agriculture. As part of the ANR Amethyst, this work is to develop, adapt and evaluate a hydro-meteorological forecasting chain for quantifying streamflows at the outlet of a mountainous watershed (Rheraya wadi, Marrakech region, Morocco), a pilot basin instrumented since 2003 as part of SudMed project. Two sets of atmospheric forcing were used: (1) The first was generated by spatializing meteorological data observed on 6 stations (Asni, Aremdt, Tachedert, Oukaimeden, Imskerbour and Neltner) using the semi-physical module Micromet (Liston and Elder, 2006) on the hydrological period September 2003 - August 2012; (2) the second is provided by the SAFRAN re-analysis, implemented by the Metoffice of Morocco (Casablanca, Morocco), during the period August 2004 - July 2008. These two sets were then used as inputs for the ISBA surface model, within the modeling platform SURFEX. Finally, runoff and drainage simulations derived from ISBA were forced into the hydrological model RAPID to predict streamflows. The flows predictions and the snow covered area (SCA) were compared respectively to the observations available for the 2003-2009 period and to the daily MODIS products of SCA. Despite time unsystematic lags and low biases on flow values, the initial results are encouraging due to topographical and hydro-complexity of the studied area. Despite a slight tendency to underestimate the SCA for the "Micromet" run and to over-estimate for the "Safran" run, SCA is well reproduced with a determination coefficient of r²=0.76 and r²=0.79, respectively. Given the complex topography of the basin, a sensitivity analysis to the size of the grid point (from 8 km to 250 m) was conducted. If the different simulated series of SCA are close from a resolution to another, streamflows simulations are, by contrast, highly sensitive to the resolution

  9. Effects of a Reservoir Water on the GW Quality in a Coastal Aquifer of Semi-arid Region, North-east of Tunisia

    Science.gov (United States)

    Uchida, C.; Kawachi, A.; Tsujimura, M.; Tarhouni, J.

    2015-12-01

    This study investigated effects of a reservoir water in a salinized shallow aquifer based on spatial distribution of geochemical properties in groundwater (GW). In many coastal shallow aquifers of arid and semi-arid regions, groundwater table (GWT) depression and salinization have occurred due to GW overexploitation. In Korba aquifer, north-east of Tunisia, after a dam reservoir has been constructed in order to assure a water resource for irrigation, improvement of GW level and quality have been observed in the downstream area of the dam (area-A), while the GW in the other area (area-B) still has high salinity. This study, therefore, aimed to investigate the effects of the reservoir water on the GW quality. In June 2013, water quality survey and sampling were carried out at 60 wells (GW), a dam reservoir, river and the sea. Major ions, boron, bromide, and oxygen-18 and deuterium in collected samples were analyzed. From the results, in the area-B, the GWT was lower than the sea level and the high salinity were observed. The Br- concentration of the GW was correlated with the Cl- concentration, and the values of B/Cl- and Br-/Cl- of the GW were similar to the seawater. Since the GWT depression allowed the seawater to intrude into the aquifer, the GW salinization occurred in this area. On the other hand, in the area-A, GWT was higher than the seawater level, and the Na+ and Cl- concentrations were lower than the area-B. Especially, in the irrigated areas by using the reservoir water, the isotopic values, B/Cl- and Br-/Cl- of the GW were relatively higher than the others. The reservoir water has high isotopic values due to evaporation effect, and the B/Cl- and Br-/Cl- values become higher due to organic matters in sediment of the reservoir or soil in the filtration process. Thus, in addition to the direct infiltration from the reservoir into the aquifer, irrigation using a reservoir water probably has a positive impact on the GW quality in this area.

  10. Geochemistry and isotope evolution of groundwater and recharge mechanisms at a uranium production centre in the semi-arid region of Caetite-BA, Brazil: Implications for groundwater management

    International Nuclear Information System (INIS)

    The semi-arid region of the northeast of Brazil is characterized by a lack of superficial waters due to low precipitation and high evaporation rates. Due to these adverse climatic conditions, intense pressure is being put on the use of groundwater resources. However, there is still insufficient knowledge about the aquifer system which is causing an overexploitation of the water resources. Groundwater is pumped from a fractured, crystalline aquifer of low productivity, where wells show generally yield rates lower than 3 m3 · h-1. The study was carried out in a semi-arid area located in the centre-south region of Bahia State at an elevation of 900 m a.s.L, where were discovered several radioactive anomalies by aerogeophysical surveys performed during the 1970s, that give origin to the uranium province named Lagoa Real.The research approach included isotopic and geochemical analysis of groundwater sampled from 25 wells placed in crystalline rock areas (granite or gneiss) covered by thin layers of residual soil or alluvial sediments. Groundwater is Na-HCO3 type water and relative high concentrations of Cl and SO4- are observed in some groundwater.The stable isotope data (δH and δ18O) showed that evaporation plays a role in the salinization of groundwater.The radiocarbon ages, corrected by carbonate dissolution (through δ13C and DIC), showed very young waters that were recently recharged, perhaps during the last few decades These data discard the possibility that groundwater salinization was caused by discharge of deeper saline groundwater through faults associated to a regional groundwater flow system. The presence of an active shallow groundwater flow system offers better possibility for sustainable use of the groundwater resources in this semi-arid region of Brazil. (author)

  11. Dust aerosol effect on semi-arid climate over Northwest China detected from A-Train satellite measurements

    OpenAIRE

    Huang, J; Minnis, P.; Yan, H; Yi, Y.; Chen, B; Zhang, L.; J. K. Ayers

    2010-01-01

    The impact of dust aerosols on the semi-arid climate of Northwest China is analyzed by comparing aerosol and cloud properties derived over the China semi-arid region (hereafter, CSR) and the United States semi-arid region (hereafter, USR) using several years of surface and A-Train satellite observations during active dust event seasons. These regions have similar climatic conditions, but aerosol concentrations are greater over the CSR. Because the CSR is close to two major dust source regions...

  12. Environmental Effects of Irrigation in Arid and Semi-Arid Regions Efectos Ambientales del Riego en Regiones Áridas y Semi-Áridas en América Latina

    Directory of Open Access Journals (Sweden)

    Alicia Fernández Cirelli

    2009-12-01

    Full Text Available This article reviews the state of the art with respect to the environmental effects of irrigated agriculture on water and soil quality in arid and semi-arid regions on a field scale. Information is scarce and fragmentary. Examples in selected areas of other arid and semi-arid regions in the world clearly show the importance of studying the environmental impact of irrigation practices on water and soil quality. Studies mainly refer to waterlogging and salinization. As regards agrochemicals, fertilizers have been taken into account through nitrate leaching. The impact of micropollutants such as pesticides and heavy metals on water and soil quality is studied mainly by modeling. Pharmaceutical compounds emerge as pollutants when wastewater is used for irrigation without any previous treatment, situation which is now the object of new studies. There is an obvious need to study in-depth knowledge related to appropriate technologies for the use, treatment, and reuse of wastewater which is a valuable resource in arid and semi-arid regions.En este trabajo se presenta una revisión del estado del arte relativo a los efectos ambientales de la agricultura bajo riego en la calidad del agua y de los suelos en regiones semiáridas y áridas de América Latina a escala de campo. La información relevada es escasa y fragmentaria. Ejemplos en áreas seleccionadas de otras regiones del mundo muestran claramente la importancia del estudio del impacto ambiental de las prácticas de riego en la calidad de agua y del suelo. La mayor parte de los estudios se refieren a anegamiento y salinización de suelos. En relación a los agroquímicos, los fertilizantes han recibido mayor atención, en particular considerando la lixiviación de nitratos. El impacto de los microcontaminantes, como los pesticidas o los metales pesados, se ha estudiado mayormente a través de la aplicación de modelos. Los compuestos farmacéuticos surgen como contaminantes cuando las aguas servidas

  13. Biodigestor for validation of the productive system self-sustainable in the Brazil semi-arid; Biodigestor para validacao de sistema produtivo auto-sustentavel no semi-arido

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Paulo C.M. [Universidade Federal do Ceara (UFCE), Fortaleza, CE (Brazil). Dept. de Engenharia Eletrica; Silveira Neto, Jose W.; Diniz, Magilce M.N. [Instituto Joazeiro de Desenvolvimento Sustentavel, Fortaleza, CE (Brazil); Canafistula, Francisco J.F. [Universidade Federal do Ceara (UFCE), Fortaleza, CE (Brazil). Dept. de Engenharia Agricola

    2004-07-01

    The present paper shows the first phase of a project about the use of digester adapted to the conditions of the semi-arid areas of the Brazilian Northeast region. The project aims to analyze the technical, economical, financial and environmental viability of a production system based on the use of digesters. (author)

  14. Remote Sensing Analysis of Lake Dynamics in Semi-Arid Regions: Implication for Water Resource Management. Lake Manyara, East African Rift, Northern Tanzania

    OpenAIRE

    Dorothea Deus; Richard Gloaguen

    2013-01-01

    We show here that a remote sensing (RS) approach is a cost-efficient and accurate method to study water resource dynamics in semi-arid areas. We use a MODIS surface reflectance dataset and a Modified Normalized Difference Water Index (MNDWI) to map the variability of Lake Manyara’s water surface area using a histogram segmentation technique. The results indicate that Lake Manyara’s water surface coverage has been decreasing from 520.25 km2 to 30.5 km2 in 2000 and 2011 respectively. We observe...

  15. Improving estimates of water resources in a semi-arid region by assimilating GRACE data into the PCR-GLOBWB hydrological model

    Science.gov (United States)

    Tangdamrongsub, Natthachet; Steele-Dunne, Susan; Gunter, Brian; Ditmar, Pavel; Sutanudjaja, Edwin; Sun, Yu; Xia, Ting; Wang, Zhongjing

    2016-04-01

    An accurate estimate of water resources is critical for proper management of both agriculture and the local ecology, particularly in semi-arid regions where water is scarce. Imperfections in model physics, uncertainties in model land parameters and meteorological data, and the human impact on land changes often limit the accuracy of hydrological models in estimating water storages. To address this problem, this study investigated the assimilation of Terrestrial Water Storage (TWS) estimates derived from the Gravity Recovery And Climate Experiment (GRACE) data using an Ensemble Kalman Filter (EnKF) approach. The region considered was the Hexi Corridor of Northern China. The hydrological model used for the analysis was PCR-GLOBWB, driven by satellite-based forcing data from April 2002 to December 2010. The performance of the GRACE Data Assimilation (DA) scheme was evaluated in terms of its impact on the TWS as well as on the individual hydrological storage estimates. The capability of GRACE DA to adjust the storage level was apparent not only in the TWS but also in the groundwater component, which had annual amplitude, phase, and long-term trend estimates closer to the GRACE observations. This study also assessed the impact of considering correlated errors in GRACE-based estimates. These were derived based on the error propagation approach using the full error variance-covariance matrices provided as a part of the GRACE data product. The assessment was carried out by comparing the EnKF results after excluding (EnKF 1D) and including (EnKF 3D) error correlations with the in situ groundwater data from 5 well sites, and the in situ streamflow data from two river gauges. Both EnKF 1D and 3D improved groundwater and streamflow estimates compared to the results from the PCR-GLOBWB alone (Ensemble Open Loop, EnOL). Although EnKF 3D was inferior to 1D at some groundwater measurement locations, on average, it showed equal or greater improvement in all metrics. For example

  16. Surface soil moisture retrieval over a Mediterranean semi-arid region using X-band TerraSAR-X SAR data

    Science.gov (United States)

    Azza, Gorrab; Zribi, Mehrez; Baghdadi, Nicolas; Mougenot, Bernard; Boulet, Gilles; Lili-Chabaane, Zohra

    2015-04-01

    Mapping surface soil moisture with meter-scale spatial resolution is appropriate for multi- domains particularly hydrology and agronomy. It allows water resources and irrigation management decisions, drought monitoring and validation of multi-hydrological water balance models. In the last years, various studies have demonstrated the large potential of radar remote sensing data, mainly from C frequency band, to retrieve soil moisture. However, the accuracy of the soil moisture estimation, by inversing backscattering radar coefficients (σ°), is affected by the influence of surface roughness and vegetation biomass contributions. In recent years, different empirical, semi empirical and physical approaches are developed for bare soil conditions, to estimate accurately spatial soil moisture variability. In this study, we propose an approach based on the change detection method for the retrieval of surface soil moisture at a higher spatial resolution. The proposal algorithm combines multi-temporal X-band SAR images (TerraSAR-X) with different continuous thetaprobe measurements. Seven thetaprobe stations are installed at different depths over the central semi arid region of Tunisia (9°23' - 10°17' E, 35° 1'-35°55' N). They cover approximately the entire of our study site and provide regional scale information. Ground data were collected over agricultural bare soil fields simultaneously to various TerraSAR-X data acquired during 2013-2014 and 2014-2015. More than fourteen test fields were selected for each spatial acquisition campaign, with variations in soil texture and in surface soil roughness. For each date, we considered the volumetric water content with thetaprobe instrument and gravimetric sampling; we measured also the roughness parameters with pin profilor. To retrieve soil moisture from X-band SAR data, we analyzed statistically the sensitivity between radar measurements and ground soil moisture derived from permanent thetaprobe stations. Our analyses are

  17. Influência da aptidão produtiva (leite ou carne sobre a libido de bodes de raças exóticas e naturais da região semi-árida do nordeste brasileiro Influence of the productive aptitude (milk or meat on the libido of exotic male goats it is naturalized to the semi-arid area from the brazilian northeast region

    Directory of Open Access Journals (Sweden)

    Fernando Carlos Borja dos Santos

    2005-06-01

    Full Text Available Dezesseis reprodutores caprinos agrupados de acordo com a aptidão produtiva (carne ou leite foram avaliados quanto à libido. Em cada grupo racial (Anglo-Nubiano e Pardo-Sertanejo - para leite; e Boer e Moxotó - para carne, havia quatro animais. Cinco fêmeas mestiças de Anglo-Nubiano foram utilizadas, todas elas estrogenizadas. O experimento foi realizado em Patos - PB (região semi-árida do Nordeste brasileiro durante 42 dias, entre agosto e setembro de 2002. Os trinta dias iniciais foram reservados para o período adaptativo dos animais e os últimos doze dias, para o processo intensivo de coleta seminal, que obedeceu a um sistema contínuo e crescente de coletas dividido em três fases, cada uma com quatro dias: fase 1, uma coleta ao dia; fase 2, três coletas ao dia; fase 3, seis coletas ao dia. Durante as coletas seminais, todo o comportamento sexual dos bodes foi monitorado, inclusive a libido. Encontrou-se influência significativa (P Sixteen male goats were agrouped accord to productive aptitude (meat or milk and they were evaluated for the libido. In each racial group (Anglo-Nubiano and Pardo-Sertanejo - for milk; and Boer and Moxotó - for meat being a total of four animals. Five females crosbreed from Anglo-Nubiano in oestrous were used.. The experiment was conducted in Patos - PB (Brazilian Northeast, semi-area region during 42 days from August and September of 2002. The thirty initial days were reserved for the adaptadion period of the animals and the last twelve days the animals were submitted to intensive process of seminal collection in a continuous and growing system of collections divided in three phases, each one with four days: phase 1, a collection a day; phase 2, three collections a day; phase 3, six collections a day. During the seminal collections the whole sexual behavior of the male goats was monitored, besides the libido. The data shown a significant influence (P <0.05 on the productive aptitude as well the

  18. Integrating management objectives and grazing strategies on semi-arid rangelands

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Rangelands account for almost half of Nebraska's 24 million acres. Much of these expansive natural resource areas are in the semi-arid climatic region of Nebraska...

  19. Utilization of Indigenous Technical Knowledge (ITK'S) in Arid and Semi-Arid Regions of Eastern Kenya: A Coping Strategy to Shocks of Market Utilization

    International Nuclear Information System (INIS)

    Most of the farmers in the arid and semi arid are poorly endowed with resources. Market liberalisation and withdrawal of government support (subsidies) in accessing some of the modern technologies has led to decreased use of most of the modern recommended technologies due to their high prices. A a coping strategy most of the resources poor farmers have turned to utilization of the indigenous technology to sustain their agricultural production. The main objective of this paper is to document the indigenous technologies utilized by farmers, explore the possibility of refining/calibrating and up-scaling them and the advantages and disadvantages of utilizing them as identified by the farmers. The method for data collection was by use of interviews the farmers who were stratified in terms of gender and age sets (young, middle aged and old) and data analysed by use of qualitative methods. The results indicate that, most farmers do utilize indigenous technology in crops, livestock pests, diseases, soil and water conservation as cropping strategies to increase input prices due to market liberalization and withdrawal of government subsidies. It was also observed that, there is need for scientists to calibrate the most important practices for improved adoption and up-scaling of the main indigenous technologies within and outside the study areas

  20. Assessment of vulnerability in karst aquifers using a quantitative integrated numerical model: catchment characterization and high resolution monitoring - Application to semi-arid regions- Lebanon.

    Science.gov (United States)

    Doummar, Joanna; Aoun, Michel; Andari, Fouad

    2016-04-01

    Karst aquifers are highly heterogeneous and characterized by a duality of recharge (concentrated; fast versus diffuse; slow) and a duality of flow which directly influences groundwater flow and spring responses. Given this heterogeneity in flow and infiltration, karst aquifers do not always obey standard hydraulic laws. Therefore the assessment of their vulnerability reveals to be challenging. Studies have shown that vulnerability of aquifers is highly governed by recharge to groundwater. On the other hand specific parameters appear to play a major role in the spatial and temporal distribution of infiltration on a karst system, thus greatly influencing the discharge rates observed at a karst spring, and consequently the vulnerability of a spring. This heterogeneity can only be depicted using an integrated numerical model to quantify recharge spatially and assess the spatial and temporal vulnerability of a catchment for contamination. In the framework of a three-year PEER NSF/USAID funded project, the vulnerability of a karst catchment in Lebanon is assessed quantitatively using a numerical approach. The aim of the project is also to refine actual evapotranspiration rates and spatial recharge distribution in a semi arid environment. For this purpose, a monitoring network was installed since July 2014 on two different pilot karst catchment (drained by Qachqouch Spring and Assal Spring) to collect high resolution data to be used in an integrated catchment numerical model with MIKE SHE, DHI including climate, unsaturated zone, and saturated zone. Catchment characterization essential for the model included geological mapping and karst features (e.g., dolines) survey as they contribute to fast flow. Tracer experiments were performed under different flow conditions (snow melt and low flow) to delineate the catchment area, reveal groundwater velocities and response to snowmelt events. An assessment of spring response after precipitation events allowed the estimation of the

  1. Water politics in Brazil subsidiarity and humanity aspects for the semi-arid sustainable river basin management

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Patricia Borba Vilar; Xavier, Yanko Marcius de Alencarr [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. de Direito Publico

    2010-02-15

    This paper examines Brazilian national constitutional law interpretation about water resources management, environmental protection and sustainable development principles. Institutional scenario is characterized under an economical format, important to conciliate human rights guaranties, national development and water protection. We provide subsidies for legal and institutional analysis considering human rights and an equity desirable scenario. Institutional context in Brazil assumes that Federal Law No. 9433/97 determined that water management must improve its multiple uses, decentralization and social participation. Water resources management in Brazil is legally and institutionally marked by the presence of the subsidiarity principle. We analyze the case in current national scene, with its consequent conflict in Sao Francisco River Basin, a semi arid Northeastern River Basin. This work also reflects some aspects of water pricing as defined by State politics. Some parameters are discussed as an elementary presupposition for water regulatory instruments that will define respective water management policy. Therefore, when defining criteria water fees, laws must comply with constitutional principles and the parameters established by the Brazilian Water Law (Law 9.433/97). The lack of reasonability and proportionality in dealing with the formal aspects and, specially, in defining water allocation, can obstruct the subsidiary principle application as determined by the Law 9433/97 and National Water Resources Policy. The question is observed in a more detailed focus over Northeastern Brazilian semi-arid region, where scarcity and traditional relations on politics are difficult to deal with, according to a renewed vision of the State and sustainable development principles. (author)

  2. Myxomycetes ocorrentes em áreas de caatinga e brejo de altitude no sertão de Pernambuco, Brasil Myxomycetes from caatinga and brejo de altitude areas in the semi-arid region of Pernambuco, Brazil

    Directory of Open Access Journals (Sweden)

    Nylber Augusto da Silva

    2012-12-01

    Full Text Available O bioma Caatinga, localizado na região semiárida brasileira, está distribuído em nove estados, incluindo Pernambuco. Os objetivos deste estudo foram: obter informações que contribuam para a compreensão da diversidade alfa e gama da microbiota da Caatinga; comparar a composição da mixobiota em áreas de caatinga situadas nos municípios de Serra Talhada (ST e Mirandiba (M com a encontrada em um enclave de floresta úmida (brejo de altitude situado no município de Triunfo (T. Os espécimes foram coletados sobre restos lenhosos (173, folhedo (26, restos de plantas suculentas (3, casca de árvore viva (1 e fezes de herbívoros (1. Hemitrichia calyculata foi a espécie mais abundante (60 registros; outras espécies comuns foram Arcyria cinerea (20, Ceratiomyxa fruticulosa (19, A. denudata (16 e H. serpula (13. Apresenta-se uma lista comentada de 37 espécies, distribuídas em 17 gêneros, sete famílias e cinco ordens. A mixobiota dos três ambientes difere entre si: CC M/ST = 0,25; CC M/T = 0,06; CC ST/T = 0,39. A relação espécie/gênero foi muito baixa na caatinga e relativamente alta na floresta úmida (S/G M = 1,0; S/G ST= 1,3; S/G T = 2,14. A abundância de espécimes e o número de espécies (M = 4/4; ST= 26/12; T= 172/29 tendem a aumentar com a elevação da altitude e da pluviosidade. Fuligo megaspora é referida pela primeira vez para o Nordeste e Didymium perforatum é um novo registro para o Brasil.The Caatinga biome, situated in the Brazilian semi-arid region, is distributed among the territories of nine states, including Pernambuco. The objectives of this study were: (1 to understand the alpha and gamma diversity of the Caatinga myxobiota; and (2 to compare the composition of the myxobiota present in two areas of typical xerophilous vegetation situated in Serra Talhada (ST and Mirandiba (M municipalities with an enclave of rain forest situated in the municipality of Triunfo (T. Specimens were collected on woody debris (173

  3. Does total tannin content explain the use value of spontaneous medicinal plants from the Brazilian semi-arid region?

    OpenAIRE

    Julio M. Monteiro; João S.N. de Souza; Ernani M.F. Lins Neto; Keli Scopel; Elzineide F. Trindade

    2014-01-01

    Due to the current predatory exploitation and consequent extinction of native medicinal plants around the world, strategies have been proposed aiming at the sustainable use of these resources. Accordingly, this study aims at verifying the differences in tannin compounds content in the bark of eleven species with high use value (UV) and also relating the amounts of tannins with their therapeutic indications. To quantify the total phenolic content in the samples the Folin-Ciocalteu reagent was ...

  4. Dynamics of traditional knowledge of medicinal plants in a rural community in the Brazilian semi-arid region

    Directory of Open Access Journals (Sweden)

    Flávia dos Santos Silva

    2011-06-01

    Full Text Available Human beings have accumulated rich experience with natural resources over time, but such knowledge can be strongly influenced by several factors, such as age, sex and occupation. This study focuses on the influence of these factors on knowledge of medicinal plants in a rural community in northeastern Brazil. Data were collected through semi-structured interviews with 102 people, with the number of plants and uses cited studied for quantitative analysis. Through this research, it was possible to show that the social variables studied (age, sex and informants occupation have contributed to the formation of different patterns of knowledge regarding medicinal resources. The results indicate that awareness of this dynamic is necessary for the proper implementation of projects where the goal is the sustainable use of natural resources (because it indicates the different levels of knowledge within a community, for studies intended to discover new drugs (because it indicates the peculiarities of certain groups, and for biodiversity conservation strategies.

  5. The Fragile Ecosystem Types in Arid and Semi-Arid Region of China and Their Degradation Causes%我国干旱半干旱地区脆弱生态系统及其退化成因

    Institute of Scientific and Technical Information of China (English)

    关中美; 郝成元

    2013-01-01

    In ecological and environmental problems of present world,ecological vulnerability is one of the focus issues.Based on analysis on three main courses in arid and semi-arid region of China,it is analyzed on the formation and traits of main type fragile ecological systems.In this study area,main courses includes grassland degradation,desertification and salinization while main fragile ecological systems refer to degraded grassland ecosystem,irrigated oasis ecosystem,desert ecosystem,wetland ecosystem and farming-pastoral ecosystem.In conclusion,both climate anomalies and human irrational activities are main reasons,which resulted in fragile ecosystem being in a vicious circle for a long time.The former refers to both climate change and climate variability while the latter includes over-grazing,disorder-reclaiming,excessiveutilizing of water resources,misuse and gouging natural resources,et al.These conclusions will provide theoretical basis so as to prevent further deterioration of ecosystem and comprehensive harnessing in arid and semi-arid region of China.%当今世界生态与环境的诸多问题中,生态系统脆弱性是焦点问题之一.依据我国干旱半干旱地区草场退化、土地沙漠化及盐碱化等三种主要问题的剖析结果,分析了退化草原生态系统、绿洲生态系统、荒漠生态系统、湿地生态系统、农牧交错生态系统等五类主要脆弱生态系统的成因和生态性状.最后得出结论:气候异常和人类非理性活动是造成脆弱生态系统长时期处于恶性循环的主要原因,前者表现在气候变化和气候变异两方面,后者则以超载放牧、无序垦荒、无度利用有限水资源、乱樵滥采资源等四类为主.这些研究结论为我国干旱半干旱地区防止脆弱生态系统进一步退化和生态综合整治提供了理论基础.

  6. The legacy of organochlorine pesticide usage in a tropical semi-arid region (Jaguaribe River, Ceará, Brazil): Implications of the influence of sediment parameters on occurrence, distribution and fate.

    Science.gov (United States)

    Oliveira, André H B; Cavalcante, Rivelino M; Duaví, Wersângela C; Fernandes, Gabrielle M; Nascimento, Ronaldo F; Queiroz, Maria E L R; Mendonça, Kamila V

    2016-01-15

    Between the 1940s and 1990s, immeasurable amounts of organochlorine pesticides (OCPs) were used in endemic disease control campaigns and agriculture in the tropical semi-arid regions of Brazil. The present study evaluated the legacy of banned OCP usage, considering the levels, ecological risk and dependence on sediment physicochemical properties for the fate and distribution in the Jaguaribe River. The sum concentration of OCPs (ΣOCPs) ranged from 5.09 to 154.43 ng·g(-1), comparable to the levels found in other tropical and subtropical regions that have traditionally used OCPs. The environmental and geographical distribution pattern of p,p-DDT, p,p-DDD and p,p-DDE shows that the estuarine zone contained more than 3.5 times the levels observed in the fluvial region, indicating that the estuary of the Jaguaribe River is a sink. The temporal pattern indicates application of dichloro-diphenyl-trichloroethanes (DDTs) in the past; however, there is evidence of recent input of these pesticides. High ecological risk was observed for levels of γ-hexachlorocyclohexanes (γ-HCH) and heptachlor, and moderate ecological risk was observed for levels of DDTs in sediments from the Jaguaribe River. The heptachlor, γ-HCH and hexachlorobenzene (HCB) concentrations depend on the organic and inorganic fractions of sediment from the Jaguaribe River, whereas the p,p-DDE, p,p-DDD, p,p-DDT and α-endosulfan concentrations depend solely on the organic fraction of the sediment.

  7. Fuel consumption of tractor for different soil types in semi-arid regions; Consumo de combustivel de um trator agricola para diferentes tipos de solo em regioes semi-aridas

    Energy Technology Data Exchange (ETDEWEB)

    Montanha, Gustavo K. [Universidade Estadual Paulista (FAC/UNESP), Botucatu, SP (Brazil). Fac. de Ciencias Agronomicas. Dept. de Engenharia Rural], E-mail: gmontanha@fca.unesp.br; Guerra, Saulo P.S. [Universidade Estadual Paulista (UNESP), Botucatu, SP (Brazil). Dept. de Gestao e Tecnologia Agroindustrial; Andrade-Sanchez, Pedro; Heun, John [The University of Arizona, Maricopa, AZ (United States); Monteiro, Leonardo A. [The University of Arizona (MAC/UA), Maricopa, AZ (United States). Maricopa Agricultural Center

    2010-07-01

    The appropriate use of agricultural machinery enables greater operational efficiency and higher productivity for the farmer. Some factors such as soil type can influence the fuel consumption, one of the biggest costs. This study aimed to compare the fuel consumption of a tractor operating in two different conditions of soil in semi-arid regions. The area used for testing is located in the city of Maricopa, in Arizona, belonging to 'The University of Arizona'. The area 1 is classified as sandy clay loam soil (52% sand, 35% clay, 13% silt). The area 2 is classified as a sandy loam soil (71% sand, 12% clay and 17% silt). The tractor 4 x 2 TDA, with 88 kw (120 hp) engine power equipped with auto pilot system and an implement for tillage were used in the experiment. A data acquisition system was installed in the tractor to collect the data generated by the GPS and fuel consumption sensor. The results showed significant statistical difference in fuel consumption between soil textures. (author)

  8. Sustainable Small-Scale Agriculture in Semi-Arid Environments

    Directory of Open Access Journals (Sweden)

    Scott Ingram

    2011-03-01

    Full Text Available For at least the past 8000 years, small-scale farmers in semi-arid environments have had to mitigate shortfalls in crop production due to variation in precipitation and stream flow. To reduce their vulnerability to a shortfall in their food supply, small-scale farmers developed short-term strategies, including storage and community-scale sharing, to mitigate inter-annual variation in crop production, and long-term strategies, such as migration, to mitigate the effects of sustained droughts. We use the archaeological and paleoclimatic records from A.D. 900-1600 in two regions of the American Southwest to explore the nature of variation in the availability of water for crops, and the strategies that enhanced the resilience of prehistoric agricultural production to climatic variation. Drawing on information concerning contemporary small-scale farming in semi-arid environments, we then suggest that the risk coping and mitigation strategies that have endured for millennia are relevant to enhancing the resilience of contemporary farmers' livelihoods to environmental and economic perturbations.

  9. Large-scale hydrological modelling in the semi-arid north-east of Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Guentner, A.

    2002-09-01

    Semi-arid areas are characterized by small water resources. An increasing water demand due to population growth and economic development as well as a possible decreasing water availability in the course of climate change may aggravate water scarcity in future in these areas. The quantitative assessment of the water resources is a prerequisite for the development of sustainable measures of water management. For this task, hydrological models within a dynamic integrated framework are indispensable tools. The main objective of this study is to develop a hydrological model for the quantification of water availability over a large geographic domain of semi-arid environments. The study area is the Federal State of Ceara in the semi-arid north-east of Brazil. Surface water from reservoirs provides the largest part of water supply. The area has recurrently been affected by droughts which caused serious economic losses and social impacts like migration from the rural regions. (orig.)

  10. Utilization of solar electric fence for containment of caprine in familiar production of the Pernambuco semi-arid region; Utilizacao de cerca eletrica solar para confinamento de caprinos na producao familiar do semi-arido pernambucano

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Heitor Scalambrini; Costa Neto, Guilherme [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Nucleo de Apoio a Projetos de Energias Renovaveis], Email: naper@ufpe.br; Araujo, Kassia; Silva, Gerson Flavio da; Raquel, Karine [ONG NAPER SOLAR, Recife, PE (Brazil). Centro de Estudos e Projetos], Email: nsolar@terra.com.br

    2006-07-01

    The Center for Studies and Projects - Naper Solar is an NGO, which works for the dissemination of use of alternative energies resources in the semi-arid Brazilian Northeast in collaboration with the Federal University of Pernambuco. It has implemented caprine raising systems in the back lands of Pajeu in the State of Pernambuco making use of electrified fences energized by solar energy.This project was executed in a joint effort with the City Halls of Afogados da Ingazeira e Sao Jose do Egito and the NGOs Diaconia and the Northeast Woman House and has benefited 20 families of farmers from 9 rural communities. It is funded by a Technical Cooperation Program established between the National Fund for the Environment - Ministry for the Environment and the Netherlands Government. The implemented system, in opposition to the traditional extensive production system, allow for a more animal sanitary control - minimizing the risks of contamination; a more controlled and balanced feeding system - taking into account the weight gaining factor together with pasture management, leading the a guarantee of food supply for the animals. Other advantages of this system include the reduction of fence cost and less deforesting. Electrical fences used in the contention of caprine are built with only 4 straight wires, fixed with isolators on wood posts spaced 10 m from each other, while the conventional fences use 9 barbed-wire lines fixed with clamps on posts spaced 1 m from each other. Therefore, the use of electrical fences instead of the conventional one represent a cost reduction, which can go as high as 40 % of the total cost. Besides that the electrical fences have low maintenance cost, easier and faster installation and relocation. The fenced areas vary from 0.5 ha to 4 ha for the raising of 5 to 50 animals. In the electrification of a fence one needs one photovoltaic module, one electrifier, a battery, isolators (passage and corner), electric ground rods and a thunderbolt

  11. Long-term soil microbial community and enzyme activity responses to an integrated cropping-livestock system in a semi-arid region

    Science.gov (United States)

    Water availability is a significant factor limiting agriculture in many semiarid or arid regions of the world. This study is part of a larger project to develop and evaluate integrated crop and livestock systems that reduce dependence on underground water while optimizing cotton (Gossypium hirsutum)...

  12. Canola integration into semi-arid wheat cropping systems of the inland Pacific Northwestern USA

    Science.gov (United States)

    The inland Pacific Northwestern USA (iPNW) wheat-producing region has a diversity of environments and soils, yet it lacks crop diversity and is one of the few semi-arid wheat-growing regions without significant integration of oilseeds. Four major agroecological zones, primarily characterised by wate...

  13. Birds and fish as bioindicators of tourist disturbance in springs in semi-arid regions in Mexico: a basis for management

    OpenAIRE

    Palacio-Núñez, J.; Verdú, J. R.; Galante, E.; Jiménez-García, D.; Olmos-Oropeza, G.

    2007-01-01

    Tourist disturbance in semi–arid springs was analysed; birds and fish were selected as bioindicators. Media Luna spring is the biggest and most spatially complex system in the region, with the highest biodiversity levels and tourist use. Areas with the highest bird species richness and abundances showed highest structural heterogeneity and least direct human impact. No differences in species richness of fish were observed between sectors and the most abundant species were found in the sectors...

  14. Variations of Soil Moisture During the Growth Phase of Main Crops in Semi-arid Region in Gansu%黄土高原半干旱区主要作物生育期土壤水分变化

    Institute of Scientific and Technical Information of China (English)

    史晓霞

    2011-01-01

    Based on the observed soil moisture dada in the farmland of springwheat,winter wheat,benne,oat,potato and bean from 1971 to 2006 in the semi-arid region of Gansu Province,the variation character of soil moisture in the farming land was analyzed by using EOF and wavelet analysis method.Results show that the soil there kept long-term drought,and the soil moisture had 2 and 4 years variation period.The vertical change of soil moisture presented decreasing trend with soil depth increase,and soil moisture dropped down during the period of crop growth,it was smaller in summer than that in other seasons.The vertical variation of soil moisture was correlated with the sort of the crop,different crops consuming soil moisture had the obvious spatio-temporal difference.%利用黄土高原半干旱地区农业气象观测站点春小麦、冬小麦、胡麻、燕麦、马铃薯、扁豆等主要作物农田土壤含水量实测资料,采用EOF、小波等方法分析研究该区域农田土壤水分变化特征。结果表明:长期干旱是这一地区土壤水分的基本状态,土壤水分垂直分布以递减为主,深层湿度小于浅层,夏季小于其它季节,秋季得以恢复;土壤水分垂直分布的差异与不同作物关系密切,作物对土壤水分耗费存在明显时空差异。

  15. A regional field-based assessment of organic C sequestration and GHG balances in irrigated agriculture in Mediterranean semi-arid land

    Science.gov (United States)

    Virto, Inigo; Antón, Rodrigo; Arias, Nerea; Orcaray, Luis; Enrique, Alberto; Bescansa, Paloma

    2016-04-01

    In a context of global change and increasing food demand, agriculture faces the challenge of ensuring food security making a sustainable use of resources, especially arable land and water. This implies in many areas a transition towards agricultural systems with increased and stable productivity and a more efficient use of inputs. The introduction of irrigation is, within this framework, a widespread strategy. However, the C cycle and the net GHG emissions can be significantly affected by irrigation. The net effect of this change needs to be quantified at a regional scale. In the region of Navarra (NE Spain) more than 22,300 ha of rainfed agricultural land have been converted to irrigation in the last years, adding to the previous existing irrigated area of 70,000 ha. In this framework the project Life+ Regadiox (LIFE12 ENV/ES/000426, http://life-regadiox.es/) has the objective of evaluating the net GHG balances and atmospheric CO2 fixation rates of different management strategies in irrigated agriculture in the region. The project involved the identification of areas representative of the different pedocllimatic conditions in the region. This required soil and climate characterizations, and the design of a network of agricultural fields representative of the most common dryland and irrigation managements in these areas. This was done from available public datasets on climate and soil, and from soil pits especially sampled for this study. Two areas were then delimited, mostly based on their degree of aridity. Within each of those areas, fields were selected to allow for comparisons at three levels: (i) dryland vs irrigation, (ii) soil and crop management systems for non-permanent crops, and (iii) soil management strategies for permanent crops (namely olive orchards and vineyards). In a second step, the objective of this work was to quantify net SOC variations and GHG balances corresponding to the different managements identified in the previous step. These

  16. Correlations between microbial tetraether lipids and environmental variables in Chinese soils: Optimizing the paleo-reconstructions in semi-arid and arid regions

    Science.gov (United States)

    Yang, Huan; Pancost, Richard D.; Dang, Xinyue; Zhou, Xinying; Evershed, Richard P.; Xiao, Guoqiao; Tang, Changyan; Gao, Li; Guo, Zhengtang; Xie, Shucheng

    2014-02-01

    The bacterial membrane lipid-based continental paleothermometer, the MBT/CBT or MBT‧-CBT proxy (methylation index of branched tetraethers/cyclization of branched tetraethers), results in a large temperature deviation when applied in semiarid and arid regions. Here we propose new calibration models based on the investigation of >100 surface soils across a large climatic gradient, with a particular focus on semiarid and arid regions of China, and apply them to a loess-paleosol sequence. As reported elsewhere, MBT values exhibit a much higher correlation with MAAT than with summer temperature, suggesting a minimal seasonality bias; however, MBT is apparently insensitive to temperature 20 °C. Additional complexities are apparent in alkaline and arid soils, which are characterized by different relationships to climatic parameters than those in the complete Chinese (or global) dataset. For example, MBT and CBT indices exhibit a negative correlation in alkaline and arid soils, in contrast to their positive correlation in acid soils. Moreover, the cyclization ratio of bGDGTs (CBT), previously defined as a proxy for soil pH, is apparently primarily controlled by MAAT in these alkaline soils. Thus, we propose (1) a local Chinese calibration of the MBT-CBT proxy and (2) an alternative temperature proxy for use in semiarid and arid regions based on the fractional abundances of bGDGTs; the latter has a markedly higher determination factor and lower root mean square error in alkaline soils than the Chinese local calibration and is suggested to be preferred for paleotemperature reconstruction in Chinese loess/paleosol sequences. These new bGDGT proxies have been applied to the Weinan Holocene paleosol section of the Chinese Loess Plateau (CLP). The fractional abundance calibration, when applied in the Weinan Holocene paleosol, produces a total Holocene temperature variation of 5.2 °C and a temperature for the topmost sample that is consistent with the modern temperature

  17. Population Genetic Analysis Reveals a High Genetic Diversity in the Brazilian Cryptococcus gattii VGII Population and Shifts the Global Origin from the Amazon Rainforest to the Semi-arid Desert in the Northeast of Brazil.

    Science.gov (United States)

    Souto, Ana C P; Bonfietti, Lucas X; Ferreira-Paim, Kennio; Trilles, Luciana; Martins, Marilena; Ribeiro-Alves, Marcelo; Pham, Cau D; Martins, Liline; Dos Santos, Wallace; Chang, Marilene; Brito-Santos, Fabio; Santos, Dayane C S; Fortes, Silvana; Lockhart, Shawn R; Wanke, Bodo; Melhem, Márcia S C; Lazéra, Márcia S; Meyer, Wieland

    2016-08-01

    Cryptococcus neoformans and Cryptococcus gattii are responsible globally for almost one million cryptococcosis cases yearly, mostly in immunocompromised patients, such as those living with HIV. Infections due to C. gattii have mainly been described in tropical and subtropical regions, but its adaptation to temperate regions was crucial in the species evolution and highlighted the importance of this pathogenic yeast in the context of disease. Cryptococcus gattii molecular type VGII has come to the forefront in connection with an on-going emergence in the Pacific North West of North America. Taking into account that previous work pointed towards South America as an origin of this species, the present work aimed to assess the genetic diversity within the Brazilian C. gattii VGII population in order to gain new insights into its origin and global dispersal from the South American continent using the ISHAM consensus MLST typing scheme. Our results corroborate the finding that the Brazilian C. gattii VGII population is highly diverse. The diversity is likely due to recombination generated from sexual reproduction, as evidenced by the presence of both mating types in clinical and environmental samples. The data presented herein strongly supports the emergence of highly virulent strains from ancestors in the Northern regions of Brazil, Amazonia and the Northeast. Numerous genotypes represent a link between Brazil and other parts of the world reinforcing South America as the most likely origin of the C. gattii VGII subtypes and their subsequent global spread, including their dispersal into North America, where they caused a major emergence. PMID:27529479

  18. Interannual variability of a precipitation gradient along the semi-arid catchment areas for the metropolitan region of Lima- Peru in relation to atmospheric circulation at the mesoscale

    Science.gov (United States)

    Otto, Marco; Seidel, Jochen; Trachte, Katja

    2013-04-01

    The main moisture source for precipitation on the western slopes of the Central Andes is located east of the mountain range known as the Amazon basin. However, the Andean mountains, which reach up to 6000 m a.s.l., strongly influence climatic conditions along the Pacific coastline of South America as a climatic barrier for the low-level tropospheric flow and associated moisture transport from the Amazon basin. Additional, large scale subsidence caused by the South Pacific High inhabits convective rainfall at the Pacific coast where large metropolitan areas such as the Peruvian capital Lima are located. Two contrasts in precipitation can be found while crossing the Andean mountains from West to East. On the Pacific coast, at the location of the metropolitan area of Lima, no more than 10 mm mean annual rainfall occurs. In contrast, up to 1000 mm mean annual rainfall occur only 100 km east of Lima within the upper region (4000 m .a.s.l.) of the Western Cordillera. The transition takes place along the western slopes of the Western Cordillera and is characterised by a strong precipitation gradient. Here, catchment areas are located that provide most of the water resources needed to sustain an urban area of approximately 10 million people. This study investigates the interannual variability of the precipitation gradient between 1998 and 2012. The analysis is based on daily precipitation data of 22 rain gauge station, daily rainfall data of the Tropical Rainfall Mission (TRMM 3B42) at 0.25 degrees and reanalysis data at 36 km spatial resolution at the mesoscale. The reanalysis data was produced using the Weather Research and Forecasting Model. Station data was provided by the Peruvian weather service during the project "Sustainable Water and Wastewater Management in Urban Growth Centres Coping with Climate Change - Concepts for Lima Metropolitana (Peru) (LiWa)", which is financed by the German Federal Ministry of Education and Research (BMBF). We are interested in the

  19. Hydrologic modeling in semi-arid agricultural region: An integrated approach to study water resources in southern San Joaquin Valley, California

    Science.gov (United States)

    Roy, Sagarika

    deficit in the region is 135.66 +/- 11.3 mm and the total annual surplus is 291.47 +/- 24.29 mm. Irrigation should apply when this region undergoes a period of moisture deficit in the months of May to July. From September to October are months of soil water recharge; from November to early February is the period of water surplus due to winter rainfall. It was observed that the growers should apply a depth of approximately 79.37 +/- 11.3 mm to replenish the soil moisture storage over the entire field in the growing season of almond orchards.

  20. Using a Modified Soil-Plant-Atmosphere Scheme (MSPAS) to Simulate the Interaction between Land Surface Processes and Atmospheric Boundary Layer in Semi-Arid Regions

    Institute of Scientific and Technical Information of China (English)

    刘树华; 乐旭; 胡非; 刘辉志

    2004-01-01

    This paper uses a Modified Soil-Plant-Atmosphere Scheme (MSPAS) to study the interaction between land surface and atmospheric boundary layer processes. The scheme is composed of two main parts:atmospheric boundary layer processes and land surface processes. Compared with SiB and BATS, which are famous for their detailed parameterizations of physical variables, this simplified model is more convenient and saves much more computation time. Though simple, the feasibility of the model is well proved in this paper. The numerical simulation results from MSPAS show good agreement with reality. The scheme is used to obtain reasonable simulations for diurnal variations of heat balance, potential temperature of boundary layer, and wind field, and spatial distributions of temperature, specific humidity, vertical velocity,turbulence kinetic energy, and turbulence exchange coefficient over desert and oasis. In addition, MSPAS is used to simulate the interaction between desert and oasis at night, and again it obtains reasonable results.This indicates that MSPAS can be used to study the interaction between land surface processes and the atmospheric boundary layer over various underlying surfaces and can be extended for regional climate and numerical weather prediction study.

  1. Birds and fish as bioindicators of tourist disturbance in springs in semi-arid regions in Mexico: a basis for management

    Directory of Open Access Journals (Sweden)

    Palacio-Núñez, J.

    2007-06-01

    Full Text Available Tourist disturbance in semi–arid springs was analysed; birds and fish were selected as bioindicators. Media Luna spring is the biggest and most spatially complex system in the region, with the highest biodiversity levels and tourist use. Areas with the highest bird species richness and abundances showed highest structural heterogeneity and least direct human impact. No differences in species richness of fish were observed between sectors and the most abundant species were found in the sectors least perturbed by human activity. Factors that explained the bird distribution were the species´ tolerance to the effects of direct tourism (noise and direct presence of people and habitat quality, mainly riparian vegetation. Aquatic vegetation condition was very important for fish. Six bird species and two fish species were relevant as indicators of the habitat quality related to human impact. Anthropic disturbance such as tree plantation favoured some bird species, whereas aquatic vegetation removal was favourable for some fish species, such as the endemic Cichlasoma bartoni, however, both types of disturbance were unfavourable for other species; riparian vegetation removal was negative for both groups. Controlled tourism promotes good conditions for C. bartoni establishment. Efficient conservation measures such as limiting touristic distribution are necessary for all species, especially for the fish community, in order to conserve biodiversity in general.

  2. A groundwater-basin approach to conceptualize and simulate post-Pleistocene subsurface flow in a semi-arid region, southeastern New Mexico and western Texas, USA

    Science.gov (United States)

    Corbet, Thomas F.

    2000-06-01

    Numerical simulation was used to enhance conceptual understanding of the post-Pleistocene hydrogeology of a layered sequence of clastic and evaporite sediments. This work is part of an effort to evaluate the suitability of the Waste Isolation Pilot Plant (WIPP), New Mexico, USA, as a repository for transuranic waste. The numerical model is three-dimensional, extends laterally to topographic features that form the actual boundaries of a regional groundwater system, and uses a free surface with seepage face as an upper boundary condition to simulate the effect of change in recharge rate on the position of the water table. Simulation results suggest that the modern-day flow field is still adjusting to the drying of the climate that has occurred since the end of the Pleistocene Epoch. A wetter climate at the end of the Pleistocene resulted in a shallow water table, and patterns of groundwater flow were controlled by the intermediate features of the land-surface topography. As the climate became drier and the water table declined, groundwater flow began to increasingly reflect the land-surface topography at the scale of the entire groundwater basin. The modern-day flow pattern has not equilibrated with either the present recharge rate or the position of the water table.

  3. Irrigated plantations and their effect on energy fluxes in a semi-arid region of Israel - a validated 3-D model simulation

    Science.gov (United States)

    Branch, O.; Warrach-Sagi, K.; Wulfmeyer, V.; Cohen, S.

    2013-11-01

    A large irrigated biomass plantation was simulated in an arid region of Israel within the WRF-NOAH coupled atmospheric/land surface model in order to assess land surface atmosphere feedbacks. Simulations were carried out for the 2012 summer season (JJA). The irrigated plantations were simulated by prescribing tailored land surface and soil/plant parameters, and by implementing a newly devised, controllable sub-surface irrigation scheme within NOAH. Two model cases studies were considered and compared - Impact and Control. Impact simulates a hypothetical 10 km × 10 km irrigated plantation. Control represents a baseline and uses the existing land surface data, where the predominant land surface type in the area is bare desert soil. Central to the study is model validation against observations collected for the study over the same period. Surface meteorological and soil observations were made at a desert site and from a 400 ha Simmondsia chinensis (Jojoba) plantation. Control was validated with data from the desert, and Impact from the Jojoba. Finally, estimations were made of the energy balance, applying two Penman-Monteith based methods along with observed meteorological data. These estimations were compared with simulated energy fluxes. Control simulates the daytime desert surface 2 m air temperatures (T2) with less than 0.2 °C deviation and the vapour pressure deficit (VPD) to within 0.25 hPa. Desert wind speed (U) is simulated to within 0.5 m s-1 and the net surface radiation (Rn) to 25 W m-2. Soil heat flux (G) is not so accurately simulated by Control (up to 30 W m-2 deviation) and 5 cm soil temperatures (ST5) are simulated to within 1.5 °C. Impact simulates daytime T2 over irrigated vegetation to within 1-1.5 °C, the VPD to 0.5 hPa, Rn to 50 W m-2 and ST5 to within 2 °C. Simulated Impact G deviates up to 40 W m-2, highlighting a need for re-parameterisation or better soil classification, but the overall contribution to the energy balance is small (5

  4. Remote sensing for mapping soil moisture and drainage potential in semi-arid regions: Applications to the Campidano plain of Sardinia, Italy.

    Science.gov (United States)

    Filion, Rébecca; Bernier, Monique; Paniconi, Claudio; Chokmani, Karem; Melis, Massimo; Soddu, Antonino; Talazac, Manon; Lafortune, Francois-Xavier

    2016-02-01

    The aim of this study is to investigate the potential of radar (ENVISAT ASAR and RADARSAT-2) and LANDSAT data to generate reliable soil moisture maps to support water management and agricultural practice in Mediterranean regions, particularly during dry seasons. The study is based on extensive field surveys conducted from 2005 to 2009 in the Campidano plain of Sardinia, Italy. A total of 12 small bare soil fields were sampled for moisture, surface roughness, and texture values. From field scale analysis with ENVISAT ASAR (C-band, VV polarized, descending mode, incidence angle from 15.0° to 31.4°), an empirical model for estimating bare soil moisture was established, with a coefficient of determination (R(2)) of 0.85. LANDSAT TM5 images were also used for soil moisture estimation using the TVX slope (temperature/vegetation index), and in this case the best linear relationship had an R(2) of 0.81. A cross-validation on the two empirical models demonstrated the potential of C-band SAR data for estimation of surface moisture, with and R(2) of 0.76 (bias +0.3% and RMSE 7%) for ENVISAT ASAR and 0.54 (bias +1.3% and RMSE 5%) for LANDSAT TM5. The two models developed at plot level were then applied over the Campidano plain and assessed via multitemporal and spatial analyses, in the latter case against soil permeability data from a pedological map of Sardinia. Encouraging estimated soil moisture (ESM) maps were obtained for the SAR-based model, whereas the LANDSAT-based model would require a better field data set for validation, including ground data collected on vegetated fields. ESM maps showed sensitivity to soil drainage qualities or drainage potential, which could be useful in irrigation management and other agricultural applications.

  5. Decision support for on-farm water management and long-term agricultural sustainability in a semi-arid region of India

    Science.gov (United States)

    Singh, Ajay

    2010-09-01

    SummaryThe long-term success of irrigated agriculture for sustainable crop production in India depends largely on the careful management of land and water resources. Currently, some serious environmental problems of waterlogging and soil salinization are burgeoning in parts of Haryana State of India; half a million hectare area of the State is already waterlogged. Poor irrigation and drainage management and inadequate exploitation of saline ground water are the main factors responsible for this phenomenon. In order to prevent further degradation and to maintain the food production for the growing population, judicious use of natural resources is a must. A wide range of solutions could be considered to address the problems. But the effectiveness of all the solutions and their combinations cannot be verified with on-farm experiments. Simulation models by way of their predictive capability are often the only viable means of providing input to management decisions. These models can help to forecast the likely impacts of a particular alternative management strategy. In the present study a physical based one-dimensional simulation model SWASALT was employed to evaluate on-farm irrigation water management options. After successful calibration and validation with field experimentation data, several scenario building exercises have been conducted under different crop, soil and rainfall conditions. The water and salt balance component obtained for each simulation run were used to derive water management response indicators. The simulation study revealed that in most conditions, saline water of up to 7.5 dS/m can be used safely on long term basis for crop production. The simulation study further revealed that alternative use of canal and saline water had an edge over mix use. Several alternatives have been suggested for sustainable agricultural production in the region. The strategies suggested, if followed, would lend sustainability to the agricultural production besides

  6. Richness and diversity of Leguminosae in an altitudinal gradient in the tropical semi-arid zone of Brazil

    Institute of Scientific and Technical Information of China (English)

    Jacira R.LIMA; Vidal F.MANSANO; Francisca S.ARA(U)JO

    2012-01-01

    Many studies are based on the premise that,on a local scale,diversity is the result of ecological processes,whereas on a regional scale factors such as the topography,geology,hydrology,and historical and evolutionary events would influence this control.The Baturité Mountain Range (Ceará state),located in the Brazilian semi-arid zone,is considered an area of extreme importance for conservation with its vegetation varying with the altitude and slope (windward vs.leeward).On the windward (wet) slope,rainforest dominates,whereas the leeward (dry) slope is dominated by seasonal forests and thorny woodland.The aim of this study was to contribute to the knowledge of the patterns of richness and diversity of the family Leguminosae on a local scale (Baturité Mountain Range) as well as a regional scale (northeastern Brazil).The two slopes present quite distinct floras.The dry slope presents higher richness and diversity indices for Leguminosae than the wet slope.The highest diversity of Leguminosae in the dry areas did not corroborate the ideas of other studies carried out in neotropical forests (total flora) that the higher species richness was predicted for wet areas.The present study indicates that the historical and evolutionary processes influence the diversity patterns on a local scale (Baturité Mountain Range),as well as on a regional scale (Brazilian semi-arid).Our results reinforce the uniqueness of each portion of this area and its importance for conservation.

  7. An overview of biodegradation of LNAPLs in coastal (semi)-arid environment

    NARCIS (Netherlands)

    Yadav, B.K.; Hassanizadeh, S.M.

    2011-01-01

    Contamination of soil and water due to the release of light non-aqueous phase liquids (LNAPLs) is a ubiquitous problem. The problem is more severe in arid and semi-arid coastal regions where most of the petroleum production and related refinery industries are located. Biological treatment of these o

  8. Rainwater harvesting in arid and semi-arid zones (repr. 1997)

    NARCIS (Netherlands)

    Boers, Th.M.

    1994-01-01

    In arid and semi-arid regions, the scarcity of water can be alleviated by rainwater harvesting, which is defined as a method of inducing, collecting, storing, and conserving local surface runoff for agriculture. Rainwater harvesting can be applied with different systems, and this dissertation deals

  9. Fuzzy classification of arid and semi-arid region features using multi-resolution data%基于多分辨率数据的干旱和半干旱地区地物模糊分类

    Institute of Scientific and Technical Information of China (English)

    刘姣娣; 曹卫彬; 裴志远; 郭琳; 吴全

    2012-01-01

    To further improve classification accuracy of low-resolution remote data in arid and semi-arid areas,taking Shihezi county in Xinjiang province as the study area,sample windows were selected by combining PSA (purposive selection algorithm) algorithm and statistical properties of region features distribution and finally the best sample window combinations were identified. Authentic membership function was obtained by probability density estimation. Then features identifying model of the region was constructed based on category membership function,and the remote classification flowing chart of large-scale land using/covering was established by using multi-resolution data. The result showed that the classification accuracy of low-resolution data were effectively improved by extracting exquisite distribution characteristics of features in various regions through the high spatial indentifying data,compared with method of Erdas unsupervised classification,the accuracy of fuzzy classification method was improved 20%. The research provides a useful reference and guidance in the researching and application of low-resolution data.%为了进一步提高低分辨率遥感数据用于干旱和半干旱地区地物分类精度,该文以新疆石河子垦区为研究区,利用PSA(purposive selection algorithm)算法结合地物分布的统计特性对样本窗口进行选择,确定了最佳样本窗口组合;采用概率密度估计的方法获取了真实的隶属度函数,基于类别隶属度函数构建地物辨别模型;建立了多分辨率数据大尺度土地利用/覆盖遥感分类流程.研究结果表明,借助高空间分辨率数据提取各地物类别的精细分布特征,与Erdas非监督分类相比,模糊分类的总体分类精度提高了20%.该研究可为低分辨率数据的研究与应用提供借鉴.

  10. Drought Characteristics Analyzing Method Based on Palmer Index in Northeast Semi-arid Region%东北半干旱地区Palmer干旱指数特征分析方法

    Institute of Scientific and Technical Information of China (English)

    李晓辉; 杨勇; 任传友

    2013-01-01

    Palmer Index can more accurately describe the intensity of drought,but when each month or season rainfall is not balanced,the condition of disaster will be weakened because the index integrates the surplus or shortage of rainfall in each month.The improved method of combining Malikov criterion and the Palmer index to analyze the characteristics of drought is introduced.Sixty years' meteorological data,including daily precipitation,temperature,etc,from 1952 to 2011,in northeast semi-arid regionChaoyang of Liaoning province were used to analyze drought characteristics.The results show that the proposed analytic method is correct and objective.It complements the judgment of Palmer analysis by discriminating the drought characteristics of the 5 years including 1959,1960,etc.among the 60 years' experimental data from the normal years according to Palmer alone,and it can objectively reflect the actual drought features.%Palmer指标可以较准确地描述干旱的强度,但当各个月份或季节降雨量不均衡时,由于干旱指数综合了各个月份降水的盈余或短缺,使得其弱化了灾情,通过改进方法,引入了马利科夫判据与Palmer指数结合的方法分析干旱特征.分析利用东北半干旱地区辽宁省朝阳地区1952-2011年期间60年的日降水量、气温等气象数据,进行干旱特征分析,结果表明:引入马利科夫判据与Palmer指数结合的方法分析干旱特征方法正确、客观.该方法进一步对Palmer指数分析结果补充判断,有效辨别出60年的试验数据中1959,1960,1963,1993,1999年5个年份原始判定为正常旱情的年份,能够客观地反映实际旱情特征.

  11. An Overview of the Semi-arid Climate and Environment Research Observatory over the Loess Plateau

    Institute of Scientific and Technical Information of China (English)

    HUANG Jianping; ZHANG Seidou; WANG Guoyin; FENG Guanghong; YUAN Jiuyi; ZHANG Lei; ZUO Hongchao; WANG Shigong; FU Congbin; CHOU Jifan; ZHANG Wu; ZUO Jinqing; BI Jianrong; SHI Jinsen; WANG Xin; CHANG Zhoulin; HUANG Zhongwei; YANG Su

    2008-01-01

    Arid and semi-arid areas comprise about 30% of the earth's surface. Changes in climate and climate variability will likely have a significant impact on these regions. The Loess Plateau over Northwest China is a special semi-arid land surface and part of a dust aerosol source. To improve understanding and capture the direct evidence of the impact of human activity on the semi-arid climate over the Loess Plateau, the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) was established in 2005. SACOL consists of a large set of instruments and focuses on: (1) monitoring of long term tendencies in semiarid climate changes; (2) monitoring of the aerosol effect on the water cycle; (3) studies of interaction between land surface and the atmosphere; (4) improving the land surface and climate models; and (5) validation of space-borne observations. This paper presents a description of SACOL objectives, measurements, and sampling strategies. Preliminary observation results are also reviewed in this paper.

  12. Calibration,validation and application of the CERES-Maize model for sprinkled maize in the semi-arid region%半干旱地区喷灌玉米CERES-Maize模型率定验证及应用

    Institute of Scientific and Technical Information of China (English)

    温江丽; 李久生

    2015-01-01

    作物模型是确定水氮优化管理措施的有力工具,而模型的率定和验证是模拟结果推广应用的前提。利用内蒙古半干旱区2012、2013年的大型喷灌机条件下玉米水氮充足处理对 CERES-Maize模型的作物品种参数进行率定,其他不同水氮处理进行验证,并应用模型模拟了不同降雨年型下灌水施肥方案对作物产量和氮素淋失量的影响。模型验证结果表明,CERES-Maize模型可以较好地描述该地区不同水氮处理条件下玉米叶面积指数(LAI)在生育期内的变化过程。中、高灌水量处理玉米生育期内 LAI 的模拟精度(标准均方根误差 nRMSE=23.0%~37.7%,一致性指数d=0.612~0.945)优于水分亏缺较严重的处理(nRMSE=31.8%~60.6%,d=0.501~0.878)。产量和收获期干物质质量模拟值与实测值之间的相对误差变化范围为0.1%~17.7%,nRMSE变化范围为7.6%~8.7%,d变化范围为0.758~0.791,吻合程度为优。CERES-Maize模型可用以优化喷灌水氮管理措施。不同降雨年型玉米最优灌水方案为:枯水年灌水次数为10次,灌溉定额为292 mm;平水年和丰水年灌水次数分别为8次和6次,灌溉定额分别为191 mm和95 mm。不同降雨年型最优施肥方案为:基肥的施入量为40 kg/hm2,拔节期和抽穗期的施入量均为60 kg/hm2。优化水氮管理措施不仅能够获得较高的玉米产量,还能减少氮素淋失。%Crop model is an efficient tool to determine best management practices of irrigation and fertiliza⁃tion. The calibration and validation of the model is fundamentally important for applying the crop model. In this study,the data obtained from two years (2012 and 2013) experiments of maize conducted in the semi-arid region with varying irrigation and nitrogen levels under sprinkler irrigation were used to calibrate and validate the CERES-Maize model. Then the calibrated and verified model was used to evaluate the ef⁃fect of

  13. Immunomodulatory activity of extracts from Cordia superba Cham. and Cordia rufescens A. DC. (Boraginaceae, plant species native from Brazilian Semi-arid Atividade imunomoduladora de extratos de Cordia superba Cham. and Cordia rufescens A. DC. (Boraginaceae, espécies de plantas nativas do semi-árido brasileiro

    Directory of Open Access Journals (Sweden)

    José Fernando Oliveira Costa

    2008-03-01

    Full Text Available The family Boraginaceae is widely distributed in Brazil and in the Northeastern region some species are popularly used to treat symptoms of rheumatism, painful menstruation and dyspepsia. In this work we studied Cordia superba Cham. and C. rufescens A. DC., native from Brazilian Semi-arid region, in order to investigate their immunomodulatory activity. Six extracts were prepared from aerial parts of C. superba and C. rufescens. The cytotoxicity was evaluated using splenocytes from BALB/c mice. The immunomodulatory activity was determined by in vitro assays using activated mouse macrophages and lymphocytes. Peritoneal macrophages obtained from BALB/c mice were stimulated with IFN-gamma and LPS in the presence/absence of the samples. The NO production was measured indirectly through Griess method. Three samples inhibited the production of nitric oxide in values near 50% at a concentration of 100 µg/mL. To evaluate the effects of the extracts on lymphocytes, splenocytes from BALB/c mice were incubated with the samples and concanavalin A. Proliferation inhibition was determined by analysis of ³H-thymidine uptake. Samples from the two species had a strong inhibitory activity on lymphocyte proliferation and IL-2 production. Two chloroform extracts prepared from aerial parts of C. rufescens had the lowest IC50 values (7.6 and 11.0 µg/mL.A família Boraginaceae é amplamente distribuída no Brasil e na região nordeste algumas espécies são usadas popularmente no tratamento de reumatismo, dores menstruais e dispepsias. Neste trabalho foram estudadas as espécies Cordia superba Cham. and C. rufescens A. DC., nativas da região semi-árida brasileira, objetivando investigar a atividade imunomoduladora. Seis extratos foram preparados a partir de partes aéreas das espécies. A citotoxicidade foi avaliada usando culturas de esplenócitos de camundongos BALB/c. A atividade imunomoduladora foi determinada por ensaios in vitro usando macrófagos e linf

  14. A Risk-Based Assessment of Agricultural Water Scarcity Under Climate Change in a Semi-Arid and Snowmelt-Dominated River Basin

    OpenAIRE

    Moursi, Hossam

    2016-01-01

    Water scarcity is the major challenge that water managers face in semi-arid areas, especially in regions that depend on agriculture for rural livelihood. Climate change is one of the major stresses that is expected to exacerbate water scarcity problems in semi-arid regions. In this study, a risk-based approach was used to assess the climate change impacts on the risk of agricultural water scarcity in semi-arid and snowmelt-dominated river basins that are dependent on agriculture. The Sevier R...

  15. Bró, caxixe e ouricuri estratégias de sobrevivência no semi-árido baiano "Bró", chayote and uricury syagrus palm strategies of survival in the semi-arid region of Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Ana Marlúcia Oliveira Assis

    1999-08-01

    Full Text Available Trata-se de um estudo etnográfico desenvolvido no contexto do Projeto Cansanção - PROCAN - realizado no período de 1987 a 1990. Analisa-se um conjunto de informações sobre os padrões culturais que cercam o ato alimentar dos grupos sociais que habitam Cansanção, região do semi-árido baiano. Foram investigados modelos de alimentação, a partir de depoimentos das mulheres trabalhadoras rurais, observando-se as estratégias de sobrevivência alimentar, enquanto ações concretas com vistas a assegurar a reprodução da unidade familiar. O medo da proximidade da doença e da morte são referências fundamentais como modos de conceber a vida e de definições de hábitos alimentares, apoiadas pela compreensão particular de seus próprios mundos. Os hábitos que cercam o ato alimentar em Cansanção indicam uma relação entre a sobrevivência do corpo e a reprodução da unidade familiar, permeados pelo cotidiano da seca. A atividade central, o trabalho da roça, subordinado às condições precárias de vida permite a produção e reprodução de formas de conceber a vida, e em particular, define os vários conceitos e classificações sobre as necessidades de alimentar o corpo. Em algumas áreas do município de Cansanção, observa-se um modo de conceber o alimento a partir de uma razão subordinada a valores do comércio, mas o fenômeno da seca constitui ainda o determinante da cultura alimentar da população e de suas ações concretas para solucionar a carência alimentar no grupo familiar.This study was developed within the context of the project Cansanção - PROCAN- developed by the Federal University of Bahia, Brazil. The study analyzed information concerning cultural patterns which surround the eating habits of the social groups which live in the semi-arid region of Bahia. It is an ethnographic study carried out over the period of 1987 to 1990. The subject of the investigation was the cultural aspect of eating habits of

  16. Mapeamento de áreas aluvionares no semiárido brasileiro por meio de dados colaterais e imagens orbitais Mapping alluvial areas in semi-arid region of Brazil through collateral data and satellite images

    Directory of Open Access Journals (Sweden)

    Helio L. Lopes

    2013-07-01

    Full Text Available A região semiárida do Brasil possui grande potencial para armazenamento de água em áreas aluvionares, podendo potencializar a pequena agricultura. Verifica-se a necessidade de uma metodologia para mapeamento dessas áreas, com o objetivo de futuros estudos in loco para implantação de barragens subterrâneas e manejo correto dos solos aluvionares. Neste sentido, objetivou-se a aplicação de imagens Landsat- Mapeador Temático 5 em conjunto com dados colaterais, como a rede de drenagem, mapa de classes de solo e mapa de relevo para auxiliar na classificação de terraços aluviais. Teve-se, como área de estudo, a bacia do Rio Pajeú, no sertão do estado de Pernambuco. Buscou-se também, por meio de dados SRTM (Shuttle Radar Topography Mission, a avaliação topográfica das áreas classificadas. Verifica-se que a utilização única de dados orbitais traz classificação incongruente mas com a inserção de dados colaterais é possível obter melhores resultados na classificação. A rede de drenagem é fundamental no mascaramento de classificações espúrias. Quando procede à análise topográfica por meio de dados do SRTM das áreas classificadas como terraços aluvionares, observa-se a inconsistência desses dados.The semi-arid region of Brazil has great potential for storing water in alluvial areas, and may give support to small-scale family farming. There is a need to establish a methodology for mapping these areas with the objective of future studies to implement underground dams and suitable management of the soils that occur on alluvial terraces. In this way, the aim of this study was to apply Landsat-Thematic Mapper images together with collateral data such as the drainage network, map of soil classes and elevation data to assist in the classification of alluvial terraces. The study area was Pajeú River basin located in the 'Caatinga' ecosystem of the Pernambuco state. Topographic assessment of the alluvial areas was done by

  17. Impacts of Fertilizer on Avena sativa Growth in High and Semi-arid Regions%施肥量对高寒半干旱地区燕麦生长的影响

    Institute of Scientific and Technical Information of China (English)

    罗振堂; 郭连云; 侯万红; 王晓兰

    2011-01-01

    [目的]研究施肥量对高寒半干旱地区燕麦生长的影响.[方法]2009年在青海省共和盆地木格滩高寒半干旱地区种植燕麦,共设4个处理.对不同处理下燕麦的株高、分蘖数、主穗长、小穗数、穗粒数、千粒重、产量进行比较.[结果]燕麦的出苗、分蘖、拔节、抽穗、开花期各处理一致,结籽期各处理相差2~6d,成熟期各处理相差13 d.不同施肥处理对燕麦生长有明显的影响,株高、分蘖数、主穗长、小稳数、稳粒数随施肥量的增加而增大,千粒重则相反.各处理燕麦草籽产量和草捆产量变化一致,表现为施肥量与产量呈非正比关系;各处理燕麦收后茬地产量和生物产量变化相同,呈随施肥量的增多产量相应增大的趋势.[结论]为提供优质、高产量的饲草提供技术依据和实践指导.%[Objective] The aim was to study impacts of fertilizer on Avena sativa growth in high and semi-arid regions. [ Method ] The experi ment was conducted at the Mugetan in the Gonghe Basin, Qinghai Province,four controlled treatments were established. Observation items in cluded plant height, tiller numbers, length of main fringe, spikelet numbers, grain numbers of spikelets, 1 000-grain weight, production. [Results] Seedling emergence, tillering, stem elongation, heading and flowering showed no differences among the four treatment, but matu ring periods were changed significantly. Initially, seed setting periods showed differences varying from 2 days to 6 days, but later maturing pe riods showed differences that even reached 13 days. Fertilizer had significant impacts on Avena satwa development. If more fertilizer was added to Avena sativa, plant height, tiller numbers, length of main fringe, spikelet numbers, and grain numbers of spikelet would be increased. Seed and grass production changed in the same step, but their changes were not in a direct proportion with feritilizer amount. The more fertilizere was

  18. Requerimento hídrico e coeficiente de cultura da cana-de-açúcar irrigada no semiárido brasileiro Water requirement and crop coefficient of irrigated sugarcane in a semi-arid region

    Directory of Open Access Journals (Sweden)

    Thieres G. F. da Silva

    2012-01-01

    Full Text Available O objetivo deste trabalho foi determinar o requerimento hídrico e o coeficiente de cultura (Kc da cana-de-açúcar irrigada durante o ciclo de soca, variedade RB 92-579, na região semiárida do Submédio do Vale do São Francisco. O experimento foi conduzido em área de cultivo comercial de cana-de-açúcar situada no município de Juazeiro, BA. Obteve-se o requerimento hídrico da cultura por meio do método do Balanço de Energia Razão de Bowen. Foram monitoradas também a biomassa acumulada e a fração da radiação fotossinteticamente ativa interceptada pela cultura (fRFA. Com os resultados constatou-se que a evapotranspiração da cana-de-açúcar atingiu uma taxa média diária de 4,7 mm, em resposta ao acúmulo de biomassa e, mas a fRFA apresentou, entretanto, influência do tombamento da cultura durante a fase de crescimento máximo. O requerimento hídrico total da cana-de-açúcar foi de 1710 mm, e o Kc atingiu o valor médio de 1,10 na fase de crescimento máximo. As equações de estimativa do Kc mensal, tendo graus dias acumulados e dias após o corte como variáveis independentes apresentaram ótimos ajustes (R2 ~ 0,95 e 0,98 e consideram a redução nos valores de Kc devida ao tombamento da cultura.The objective of this study was to determine the water requirement and crop coefficient of the irrigated sugarcane, variety RB 92-579, in the semi-arid region of the lower middle of São Francisco Valley. The experiment was carried out in a commercial area of sugarcane located in the municipality of Juazeiro in the State of Bahia. The crop water requirement was estimated with the Bowen Ratio Energy Balance method. The accumulated biomass and the photosynthetic active radiation intercepted (fPAR by the crop were monitored. The sugarcane evapotranspiration reached a mean value of 4.7 mm d-1 in response to fPAR and accumulated biomass; however presented influence of the crop lodging during the maximum growth phase. The total water

  19. Use of water from small alluvial aquifers for irrigation in semi-arid regions Uso das águas de pequenos aquíferos aluviais para irrigação nas regiões semiáridas

    Directory of Open Access Journals (Sweden)

    Julien Daniel Pierre Burte

    2011-09-01

    Full Text Available Water from small alluvial aquifers constitutes an attractive and low-cost option for irrigation and rural development in Northeastern Brazil. Based on piezometric measurements, geochemical analyses and electrical conductivity estimates, the present case study identified the main processes determining the hydrosaline dynamics of an alluvial aquifer in a small watershed inserted in the crystalline bedrock of a semi-arid region in Ceará and evaluated the availability of water for irrigation. Accumulation of salts in soil are related to evaporative flux from the aquifer and is increased by irrigation from the groundwater of the alluvial aquifer. The water in these aquifers may be used for irrigation, but represents a risk of soil salinization and alkalinization. Integrated management of surface and underground water resources in the Forquilha watershed may help control irrigation water quality (salinity and residual alkalinity, thereby rationalizing the use of local reservoirs and minimizing losses from evaporation. It has to take into account the complex dynamic of salts and water between the reservoirs, release of water into the river, floods and irrigations.A agricultura irrigada a partir da água subterrânea dos pequenos aqüíferos aluviais é uma alternativa interessante e de baixo custo para o desenvolvimento do meio rural no Nordeste brasileiro. A partir de um estudo de caso numa micro-bacia no centro da área cristalina do semiárido cearense é analisada a contribuição de características físicas (piezometria, geoquímicas e de modelos (de balanço hidrológico e de massa para identificar a origem e os principais processos que governam a dinâmica da salinidade das águas de um pequeno aqüífero aluvial e avaliar a disponibilidade de água para irrigação. A irrigação conduz a uma redistribuição dos sais da zona saturada para a zona não saturada do aqüífero, podendo ocorrer acumulação. Devido as suas características, as

  20. Conservation and restoration of degraded ecosystems in arid and semi-arid areas of northwest China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In "West Development" of China, one of the most important activities is the Natural Forest Protection Program, designed to swiftly convert the focus of management and utilization of the natural forests from a timber orientation towards forest conservation, sustainable management and environmental protection. The project covered almost all the arid and semi-arid regions in Northwest region. Accompanying this great campaign this paper studied the conservation and restoration model of degraded ecosystems in arid and semi-arid lands in Northwest China. The past practices have resulted in considerably natural forest degradation and loss through land conversion (primarily for agriculture), over-harvesting, inadequate reforestation and lack of protection. The consequences have been the loss of soil and water resources, diminished timber production capacity on a sustainable basis, and environmental losses. This paper applied Aronson's restoration model and proposed the conservation, restoration, re-allocation and preservation program for the implementation of environmental improvement and natural forest conservation.

  1. Water balance of two earthen landfill caps in a semi-arid climate

    Energy Technology Data Exchange (ETDEWEB)

    Khire, M.V. [GeoSyntec Consultants, Boca Raton, FL (United States); Benson, C.H.; Bosscher, P.J. [Univ. of Wisconsin, Madison, WI (United States)

    1997-12-31

    Water balance data are presented that were obtained from two earthen cap test sections located in a semi-arid region. The test sections were constructed on a municipal solid waste landfill in East Wenatchee, Washington, USA. One test section represents a traditional resistive barrier, and is constructed with a compacted silty clay barrier 60 cm thick and a vegetated silty clay surface layer 15 cm thick. The other test section represents a capillary barrier and has a sand layer 75 cm thick overlain by a 15-cm-thick vegetated surface layer of silt. Extensive hydrological and meteorological data have been collected since November 1992. Unsaturated hydraulic properties of soils, hydrologic parameters, and vegetation have been extensively characterized. Results of the study show that capillary barriers can be effective caps in semi-arid and arid regions. They are also cheaper to construct and can perform better than traditional resistive barriers.

  2. Using NDVI to measure precipitation in semi-arid landscapes

    Science.gov (United States)

    Birtwhistle, Amy N.; Laituri, Melinda; Bledsoe, Brian; Friedman, Jonathan M.

    2016-01-01

    Measuring precipitation in semi-arid landscapes is important for understanding the processes related to rainfall and run-off; however, measuring precipitation accurately can often be challenging especially within remote regions where precipitation instruments are scarce. Typically, rain-gauges are sparsely distributed and research comparing rain-gauge and RADAR precipitation estimates reveal that RADAR data are often misleading, especially for monsoon season convective storms. This study investigates an alternative way to map the spatial and temporal variation of precipitation inputs along ephemeral stream channels using Normalized Difference Vegetation Index (NDVI) derived from Landsat Thematic Mapper imagery. NDVI values from 26 years of pre- and post-monsoon season Landsat imagery were derived across Yuma Proving Ground (YPG), a region covering 3,367 km2 of semiarid landscapes in southwestern Arizona, USA. The change in NDVI from a pre-to post-monsoon season image along ephemeral stream channels explained 73% of the variance in annual monsoonal precipitation totals from a nearby rain-gauge. In addition, large seasonal changes in NDVI along channels were useful in determining when and where flow events have occurred.

  3. Runoff from soils on marls under semi-arid mediterranean conditions

    OpenAIRE

    D. Garnet; Blum, W. E. H.

    1996-01-01

    In semi-arid Mediterranean regions the pressure on natural resources such as water and soil is increasing. In the Maghreb, soil degradation and reservoir sedimentation are serious problems, particularly in catchment areas with a high proportion of marls. As part of an Algerian-German project of scientific-technical cooperation, the runoff from soils on marls was studied, using modern rain simulators. A description of the rainfall experiments is followed by the presentation of a simple and app...

  4. Ethno-ornithology and conservation of wild birds in the semi-arid Caatinga of northeastern Brazil

    OpenAIRE

    Alves, Rômulo Romeu Nóbrega; Leite, Railson Cidennys Lourenço; Souto, Wedson Medeiros Silva; Dandara M.M. Bezerra; Loures-Ribeiro, Alan

    2013-01-01

    The utilization of birds as pets has been recognized as one of the principal threats to global avifauna. Most of the information about the use and sale of birds as pets has been limited to areas of high biodiversity and whose impacts of anthropic actions have been widely broadcast internationally, for example for the Amazon Forest and forest remnants of Southeast Asia. The Caatinga predominates in the semi-arid region of Brazil, and is one of the semi-arid biomes with the greatest biological ...

  5. Soil Moisture Retrieval Using a Two-Dimenional L-Band Synthetic Aperture Radiometer in a Semi-Arid Environment

    Science.gov (United States)

    Surface soil moisture was retrieved from L-band radiometer data collected in semi-arid regions during the Soil Moisture Experiment in 2004 (SMEX04). The two-dimensional synthetic aperture radiometer (2D-STAR) was flown over regional-scale study sites located in Arizona, USA and Sonora, Mexico. The s...

  6. 半干旱黄土丘陵区人工植被深层土壤干化效应%Soil desiccation in deep soil layers under different vegetation types in the semi-arid loess hilly region

    Institute of Scientific and Technical Information of China (English)

    杨磊; 卫伟; 陈利顶; 蔡国军; 贾福岩

    2012-01-01

    科学评估不同植被恢复模式的土壤干化效应是目前黄土高原生态恢复一个亟需解决的关键问题。本文以半干旱黄土丘陵区14种典型人工植被为例,通过构建土壤水分相对亏缺指数CSWDI和样地土壤水分相对亏缺指数PCSWDI,定量评估了不同植被深层土壤干化效应。研究发现:除农地和撂荒草地外,各植被深层土壤水分均随土层深度的增加而升高,深层土壤水分含量同土层深度之间呈一元线性关系。不同人工植被深层土壤相对干化程度存在差异,以油松林地最高,杨树侧柏混交林地最低。不同植被类型受其自身蒸腾耗水、根系特征和耕作等影响,土壤干化的程度在剖面上存在差异,但总体趋势为随深度增加而降低。针阔叶植被配置模式土壤水分状况要稍好于阔叶纯林的配置模式。%Artificial vegetation restoration as an effective way to control serious soil erosion and improve environment conditions has taken several positive environmental effects. However, serious soil desiccation as one of negative effects also appears associated with artificial vegetation restoration lack of scientific guidance, especially in deep soil layers. To recover the fragile ecosystem of the Loess Plateau and maintain sustainable development of this region, proper artificial vegetation types should be selected based on local soil water conditions. However, methods to quantitatively evaluate soil water effect based on local rainfall and soil water conditions is urgently needed to improve, which is one of the top priorities in current research. To quantitatively evaluate the soil desiccation degree in veg- etation types, 14 vegetation types were selected to analyze the eco-hydrological effect in deep soil layers in the typical semi-arid loess hilly region. Compared Soil Water Deficit In- dex (CSWDI) and Plot Compared Soil Water Deficit Index (PCSWDI) were induced to

  7. Estratégias de Gestão da Água em Situação de Escassez: Regiões Semiáridas e Mediterrânicas Water management strategies in a scarcity situation: Semi-arid and Mediterranean regions

    Directory of Open Access Journals (Sweden)

    Joana Rosado

    2010-12-01

    Full Text Available No início do século XXI a escassez da água é inquestionável constituindo uma ameaça para a humanidade e para a biosfera. Esta situação é sentida nas regiões Áridas, Semiáridas e Mediterrânicas. A gestão dos recursos aquáticos e da disponibilidade de água é um tema complexo e de uma enorme importância estratégica para o desenvolvimento sustentável. O principal objectivo deste trabalho é apresentar e discutir estratégias de gestão da água em regiões Semiáridas e Mediterrânicas através da revisão da literatura disponível. Conclui-se que as regiões Semiáridas, devido às suas características específicas, sofrerão mais com a escassez. Relativamente ao Mediterrâneo, todos os cenários de evolução futura prevêem uma diminuição da precipitação, tendência que trará graves impactes em termos sociais e ambientais. Interessará às regiões Mediterrânicas implementar as técnicas simples e de baixo custo utilizadas nas regiões Semiáridas, muitas das quais presentemente abandonadas mas com tradições centenárias na história do Mediterrâneo.At the beginning of the 21st century, the shortage of water is unquestionable constituting a threat to humanity and the biosphere. This situation is experienced in arid, Semi-arid and Mediterranean regions. The management of aquatic resources and the availability of water is a complex issue and of a huge strategic importance for sustainable development. The main objective of this paper is to present and discuss strategies for water management in the Mediterranean and Semi-arid regions through a literature review. As a conclusion, the semi-arid regions, due to its specific characteristics, will suffer more with water scarcity. Regarding the Mediterranean, all scenarios of future developments foresee a decline in rainfall, a trend which will bring serious impacts on society and environment. Hence, Mediterranean regions should focus in implementing simple techniques and

  8. Time Profile of Three Semi-Arid Ecosystems in Africa

    Science.gov (United States)

    Anyamba, A.; Damoah, R.; Small, J. L.; Tucker, C. J.

    2015-12-01

    We examine the spatio-temporal variability of rainfall and satellite derived-vegetation index of three endorheic semi-arid ecosystems in Africa: Lake Chad (in the Sahel region), Okavango and Etosha (Southern Africa) to infer the nature and trends of the variability during the satellite data instrumental record. We utilize African Rainfall Climatology Precipitation Estimates (1983-2014) and Normalized Difference Vegetation Index (NDVI) derived from the Advanced Very High Resolution Radiometer (AVHRR: 1981-2014) and Moderate Resolution Imaging Spectroradiometer (MODIS: 2001:2014) to examine the aspects of the annual cycle and interannual variability using both time series plots and time-space diagrams. With respect to Lake Chad region, the first two decades of the series (1981-2000) show predominantly dryer than long-term average conditions with the periods 1989, 1992 and 1996/1997 as the signature drought periods coinciding with the desiccation of the Sahel region during the 1980s to early 1990s decades. The period 2000 to present is dominated by above average rainfall and NDVI with 2003, 2007 and 2012 being the most pronounced wet/greener years. The southern African ecosystems (Okavango and Etosha) show more or less a similar temporal pattern to that of Lake Chad basin, however, the wet periods are more amplified and persistent especially 2000, 2006, 2010 and 2014, with corresponding above average NDVI departures. The amplified nature of wet and dry periods present in the southern African ecosystem time series are consistent with the El Niño Southern Oscillation teleconnection patterns. Overall these three ecosystems serve as detectable fingerprints of changing climate conditions and ecosystems in these arid regions.

  9. Tailoring conservation agriculture technologies to West Africa semi-arid zones: Building on traditional local practices for soil restoration

    NARCIS (Netherlands)

    Lahmar, R.; Bationo, B.A.; Lamso, N.D.; Guéro, Y.; Tittonell, P.A.

    2012-01-01

    Low inherent fertility of tropical soils and degradation, nutrient deficiency and water stress are the key factors that hamper rainfed agriculture in semi-arid West Africa. Conservation Agriculture (CA) is currently promoted in the region as a technology to reduce soil degradation, mitigate the effe

  10. Ocorrência de ectoparasitos em avestruzes (Struthio camelus criadas no semi-árido baiano Occurence of ectoparasites in ostriches (Struthio camelus reared in semi-arid region of Bahia

    Directory of Open Access Journals (Sweden)

    Maria Ângela O. Almeida

    2008-09-01

    Full Text Available No período de maio a agosto de 2005, foram visitados 19 planteis de avestruzes na região semi-árida do município de Irecê, Bahia, objetivando identificar os ectoparasitos. As aves, predominantemente da raça "African Black", eram criadas em sistema intensivo e distribuídas, por faixa etária, em colônias, trio, casal ou creche. Durante a inspeção das aves, as plumas colhidas aleatoriamente, de várias regiões do corpo, foram acondicionadas em sacos plásticos e as larvas, colhidas das miíases, em álcool etílico a 70%. Em 74% (14/19 e 47% (04/19 dos plantéis encontravam-se avestruzes infestadas, respectivamente, pelas espécies Struthiopterolichus bicaudatus e Struthiolipeurus rheae. Somente em um plantel (5,3% foi encontrado um animal parasitado por larvas de Cochliomyia hominivorax.In the period of May to August of 2005, 19 ostrich's farms were visited in the semi-arid area of the Irecê, Bahia, in order to describe the ectoparasites. The African Black ostriches were reared in intensive system, and distributed for age group, in colonies, trio, couple or crèche. In each farm, after visually inspection of the ostrich, the feathers were taken in several areas of the body and were kept in plastic bags. The screwworms found were collected and stored in 70% ethanol. In 74% (14/19 and 47% (04/19 of the flocks were found ostriches infested, respectively, for the Struthiopterolichus bicaudatus (acari and Struthiolipeurus rheae (mallophaga. In only one flock (5.3% it was found an animal with Cochliomyia hominivorax larvae.

  11. Experimental Study on the Short-term Forecasting Model of Monthly Average Relative Humidity in Semi-arid Regions%半干旱区月平均相对湿度短期预报模型的求解及优化

    Institute of Scientific and Technical Information of China (English)

    刘丹; 孙西欢; 李永业; 石继忠

    2015-01-01

    Taking the daily measured relative humidity 52 years' data in Datong city (a typical semi-arid area) as material, based on the hydrological sequence of analysis,the characteristics of autocorrelation and partial correlation analysis were studied with the composition of stationary random sequence by eliminating uncertainty component, jump, cycle component, and seasonal forecast model A R (1) was established through the comparison of A R (P) models. The results showed that the forecast model accuracy met the requirements, which could be used for the short-term forecast of the relative humidity in Datong city in the future, and could also be used for on semi-arid areas. The average relative humidity statistical characteristic analysis and short-term forecast is benefit for promoting regional agricultural development.%以典型半干旱区大同市1996~2011年实测日相对湿度资料剔除确定性成分、跳跃成分、周期成分得到的平稳随机成分序列进行自相关和偏相关分析,对比AR(P)模型建立了季节性AR(1)预报模型.验证模型表明,预报模型精度符合要求,可对未来大同市相对湿度进行短期预报,也可用于半干旱区月平均相对湿度的统计特征分析和短期预报,进而促进地区农业发展.

  12. Situação nutricional e alimentar de pré-escolares no semi-árido da Bahia (Brasil: I.Avaliação antropométrica Nutritional status of pre-school children of the semi-arid region of Bahia (Brazil: I. Anthropometric status

    Directory of Open Access Journals (Sweden)

    Leonor M.P. Santos

    1995-12-01

    Full Text Available Foram estudados 754 pré-escolares de áreas urbanas de sete municípios do semi-árido da Bahia, Brasil. Os objetivos foram determinar a prevalência de déficit ponderal e estatural, indicativos de desnutrição atual e/ou pregressa e sua associação com a idade, sexo, renda em salário-mínimo (SM, escolaridade materna e adequação do consumo alimentar. Encontrou-se 22,9% de crianças com altura/idade abaixo de -2,0 DP (desnutrição pregressa, 19,1% com peso/idade e 3,6% com peso/altura abaixo de -2,0 DP (desnutrição atual. Em relação ao inquérito dietético somente 6,8% das crianças haviam consumido no dia anterior uma dieta que suprisse os requerimentos energéticos para sua faixa etária. Houve forte associação entre os indicadores A/l e P/l inadequados com renda familiar per capita (p=0,001 e p=0,000, respectivamente; crianças de famílias com renda per capita 1/2 SM. Em relação ao P/A como também P/l, os pré-escolares estudados no semi-árido apresentaram prevalências significativamente superiores às encontradas por pesquisa nacional realizada na mesma época (p=0,047 e p=0,000, respectivamente. Esses achados surpreendem, já que nas últimas décadas tem sido demonstrada no Brasil uma melhoria signifivativa na desnutrição e mortalidade infantil e parecem indicar que as crianças do semi-árido não lograram ainda alcançar os mesmos benefícios que o restante da população infantil brasileira.A survey of 754 preschool children was undertaken in the urban areas of seven small towns of the semi-arid region of Bahia, Northeast Brazil. The study set out to determine the prevalence of weight and height deficits, as well as to correlate them with variables such as age, family income, mother's schooling and food consumption. A prevalence of 22.9% of Height for Age (HA below -2.0 SD was found (stunting and prevalence of 19.1% and 3.6% were determined, respectively for Weight for Age (WA and Weight for Height (WH below -2

  13. Semi-arid development: competitiveness factors in biodiesel productive chain

    OpenAIRE

    Breno Barros Telles do Carmo; Dmontier Pinheiro Aragão; Heráclito Lopes Jaguaribe Pontes; Bruno Magalhães Ribeiro; Marcos Ronaldo Albertin

    2009-01-01

    The new global market competitiveness considerer the competition between productive chains (PC) or supply chains, not just between enterprises. In this case, it can be observed collaboration and cooperation enterprises that dispute with others productives chain. The PC competitiveness can be impaired if is subject by inhibitors factors, that can impairer the performance. This paper analyses these competitiveness factors inhibitors in biodiesel productive chain (CPB) in semi-arid area: exporte...

  14. 干旱半干旱地区藓结皮人工培养研究进展%A Review on the Studies of Moss Crust Artificial Cultivation in Arid and Semi-arid Region

    Institute of Scientific and Technical Information of China (English)

    王显蓉; 赵允格; 王媛

    2014-01-01

    In arid and semi-arid areas,moss crust play important ecological roles,such as improving soil resistance to wind and water erosion and enhancing soil fertility.In recent years,many studies have focused on artificial culture of moss crusts and its application in desertification control.This paper reviewed the research status and achievements on artificial moss crust cultivation in recent decades from the the aspects of reproductive biology,characteristics of growth and development of mosses,factors that affect the formation of moss crust and maintenance ability.Researches demonstrated that moss crusts could be successfully constructed in indoor and outdoor environment.However,this kind of moss crust performs poorly in maintenance ability.The majority of research for factors that affect the formation of moss crust was conducted in indoor environment,the influence mechanism in outdoor was not entirely clear.The research should be focused on how to combine the indoor training methods with the field methods,and to cultivate the moss crusts successfully in a fast and effective way.%在干旱半干旱地区,以藓类植物为优势物种的生物结皮,在抗风蚀、水蚀及增强土壤肥力等方面发挥着重要的作用.近年来随着人们对干旱半干旱地区生态环境的重视,藓结皮人工培养及其在土壤沙漠化防控方面的应用备受关注.从藓类植物的繁殖生物学、生长发育特点、藓结皮形成的影响因素及后期维持能力等方面综述了藓结皮人工培养的研究现状及主要进展,研究表明在室内和野外环境可成功构建藓结皮,然而其后期维持能力较差;藓结皮形成影响因素的研究多于室内环境下完成,野外环境下影响因素研究少见.将室内和野外培养方法相互结合,快速有效的培养藓结皮,是未来研究的重点.

  15. An Overview of Biodegradation of LNAPLs in Coastal (Semi)-arid Environment.

    Science.gov (United States)

    Yadav, Brijesh Kumar; Hassanizadeh, S Majid

    2011-09-01

    Contamination of soil and water due to the release of light non-aqueous phase liquids (LNAPLs) is a ubiquitous problem. The problem is more severe in arid and semi-arid coastal regions where most of the petroleum production and related refinery industries are located. Biological treatment of these organic contaminated resources is receiving increasing interests and where applicable, can serve as a cost-effective remediation alternative. The success of bioremediation greatly depends on the prevailing environmental variables, and their remediation favoring customization requires a sound understanding of their integrated behavior on fate and transport of LNAPLs under site-specific conditions. The arid and semi-arid coastal sites are characterized by specific environmental extremes; primarily, varying low and high temperatures, high salinity, water table dynamics, and fluctuating soil moisture content. An understanding of the behavior of these environmental variables on biological interactions with LNAPLs would be helpful in customizing the bioremediation for restoring problematic sites in these regions. Therefore, this paper reviews the microbial degradation of LNAPLs in soil-water, considering the influences of prevailing environmental parameters of arid and semi-arid coastal regions. First, the mechanism of biodegradation of LNAPLs is discussed briefly, followed by a summary of popular kinetic models used by researchers for describing the degradation rate of these hydrocarbons. Next, the impact of soil moisture content, water table dynamics, and soil-water temperature on the fate and transport of LNAPLs are discussed, including an overview of the studies conducted so far. Finally, based on the reviewed information, a general conclusion is presented with recommendations for future research subjects on optimizing the bioremediation technique in the field under the aforesaid environmental conditions. The present review will be useful to better understand the

  16. An Overview of Biodegradation of LNAPLs in Coastal (Semi)-arid Environment.

    KAUST Repository

    Yadav, Brijesh Kumar

    2011-02-22

    Contamination of soil and water due to the release of light non-aqueous phase liquids (LNAPLs) is a ubiquitous problem. The problem is more severe in arid and semi-arid coastal regions where most of the petroleum production and related refinery industries are located. Biological treatment of these organic contaminated resources is receiving increasing interests and where applicable, can serve as a cost-effective remediation alternative. The success of bioremediation greatly depends on the prevailing environmental variables, and their remediation favoring customization requires a sound understanding of their integrated behavior on fate and transport of LNAPLs under site-specific conditions. The arid and semi-arid coastal sites are characterized by specific environmental extremes; primarily, varying low and high temperatures, high salinity, water table dynamics, and fluctuating soil moisture content. An understanding of the behavior of these environmental variables on biological interactions with LNAPLs would be helpful in customizing the bioremediation for restoring problematic sites in these regions. Therefore, this paper reviews the microbial degradation of LNAPLs in soil-water, considering the influences of prevailing environmental parameters of arid and semi-arid coastal regions. First, the mechanism of biodegradation of LNAPLs is discussed briefly, followed by a summary of popular kinetic models used by researchers for describing the degradation rate of these hydrocarbons. Next, the impact of soil moisture content, water table dynamics, and soil-water temperature on the fate and transport of LNAPLs are discussed, including an overview of the studies conducted so far. Finally, based on the reviewed information, a general conclusion is presented with recommendations for future research subjects on optimizing the bioremediation technique in the field under the aforesaid environmental conditions. The present review will be useful to better understand the

  17. A geochemical and isotopic approach to recharge evaluation in semi-arid zones. Past and present

    International Nuclear Information System (INIS)

    The magnitude of any recharge to aquifers in semi-arid and arid zones is the principal uncertainty in estimating a water balance. Recent studies in Cyprus and Libyan Arab Jamahiriya are currently being used to demonstrate the application of geochemical and isotopic techniques, to the determination of both current and palaeo-recharge. In Cyprus, solute profiles of the unsaturated zone have been interpreted to provide estimates of the direct recharge component using a steady-state, mass-balance approach; results from the chloride profiles compare well with recharge estimates using tritium. In addition, it is found that some solute peaks, notably for specific electrical conductance, give a reasonably accurate record of the rainfall history during the period 1950-1975. The solute profile method is relatively unsophisticated and could be more widely applied to recharge estimation in other semi-arid areas of the world. In Libya, a clear distinction can be made using the combined isotopic, hydrological and geochemical results between regional groundwaters recharged to the upper, unconfined aquifer of the Sirte Basin before 13,000 years BP and younger waters recharged locally during the period 5000-7800 years BP. A well-defined fresh-water channel, superimposed upon the regional water quality pattern, can be traced within the aquifer for some 130 km and represents direct evidence of recharge during the Holocene. Some shallow groundwaters of similar composition to the fresh-water channel are also considered to represent recent, if intermittent, recharge which took place during historical times. It is concluded that geochemical and isotopic studies of both the unsaturated zone and of shallow groundwaters in semi-arid regions, can be used to determine not only the present-day direct recharge component, but also a recharge chronology of immediate historic times, which may be important in the estimation of long-term water resources. (author)

  18. Characteristics of black carbon aerosol and carbonaceous gases and their emission sources in semi-arid region%半干旱地区黑碳气溶胶和含碳气体特征及来源

    Institute of Scientific and Technical Information of China (English)

    陈霖; 张镭; 张磊; 曹贤洁; 黄建平; 张武; 张北斗

    2012-01-01

    Adopting observational data of multi angle absorption photometer (MAAP-5012) and the gas composition mixing ratio data of CO and CO2 of Semi-Arid Climate Observatory and Laboratory (SACOL) from September 2009 to June 2010, the characteristics and effects of source of black carbon aerosol and carbon gas in semi-arid areas of Northwest China, and the types of emissions which have impact on the concentration of black carbon were analyzed. The result indicated that average concentrations of BC, CO and CO2 were 1.75ug/m3, 601.71×10-9and 387.78x10-6, respectively. Hybrid Single Particle Lagrangian Integrated model (HYSPLIT-4) was used to distinguish the flow areas from eastern and western of the observation station. When the airstreams came from the east, the concentrations of BC, CO, CO2 were 1.38ng/m3, 462.79× 10-9 and 383.03x 10-6, respectively. When the airstreams came from the west, the concentrations of BC, CO, CO2 are 2.2ug/m3, 768.38×10-9 and 393.47×10-6, respectively. Taking the clustering analysis on the origin places of the airstreams in the height of 500m, 1500m and 3000m, get the results that when the airstreams of different height flow respective from the Middle East, Central Asia, and Europe, the concentrations of BC, CO, CO2 were higher and the values of ABC/ACO, ACO/ACO2 were larger, indicating the efficiency of fuel combustion was lower; when the airstreams transmits from Central and Northern China, the concentrations of BC, CO, CO2 were lower, and the values of ABC/ACO, ACO/ACO, were smaller, indicating the efficiency of fuel combustion is higher.%利用2009年9月~2010年6月兰州大学半干旱气候与环境观测站(SACOL)多角度吸收分光光度计(MAAP-5012)观测数据、CO和CO2气体成分混合比数据,分析了西北半干旱地区黑碳气溶胶和含碳气体特征、影响源地,以及影响黑碳浓度的捧放物类型.结果表明BC、CO、CO2平均浓度分别为1.75μg/m3、601.71×10-9、387.78×10-6.利用后向轨迹

  19. Dynamics in carbon exchange fluxes for a grazed semi-arid savanna ecosystem in West Africa

    DEFF Research Database (Denmark)

    Tagesson, Torbern; Fensholt, Rasmus; Cropley, Ford;

    2015-01-01

    The main aim of this paper is to study land-atmosphere exchange of carbon dioxide (CO2) for semi-arid savanna ecosystems of the Sahel region and its response to climatic and environmental change. A subsidiary aim is to study and quantify the seasonal dynamics in light use efficiency (ε) being a key...... that results in compensatory growth and fertilization effects. We also conclude that vegetation phenology, soil moisture, radiation, VPD and temperature were major components in determining the seasonal dynamics of CO2 fluxes. Despite the height of the peak of the growing season CO2 fluxes, the annual C budget...

  20. Rainwater harvesting in arid and semi-arid zones (repr. 1997)

    OpenAIRE

    Boers, Th.M.

    1994-01-01

    In arid and semi-arid regions, the scarcity of water can be alleviated by rainwater harvesting, which is defined as a method of inducing, collecting, storing, and conserving local surface runoff for agriculture. Rainwater harvesting can be applied with different systems, and this dissertation deals with the system of micro-catchments. A microcatchment consists of a runoff area and a basin area in which a tree is planted. The purpose of this study was to develop a design procedure for micro-ca...

  1. Effects of irrigation and plastic mulch on soil properties on semi-arid abandoned fields

    OpenAIRE

    Meulen, van der, A.; Nol, L.; Cammeraat, L.H.

    2006-01-01

    The Guadalentín Basin in Spain is one of the driest areas of Europe and has problems with high evaporation rates, and high risks of desertification exist including soil quality loss and soil erosion. Farmers in this semi-arid region use polyethylene covers on their irrigated croplands to reduce evaporation in order to enhance crop yield. When farmers abandon the acres, they leave the plastic covers on the fields. Up to now research has been concentrating on the effects of plastic covers on cr...

  2. Diet and breeding success of long-eared owls in a semi-arid environment

    OpenAIRE

    Charter M.; Izhaki I.; Leshem Y.; Roulin A.

    2012-01-01

    Only a few studies, and mostly in temperate climates in Europe, have examined the breeding and diet of long-eared owls (Asia otus) compared to studies of cavity-breeding owls, possibly because of the difficulties in reaching the nests of the former. Here we studied a population of long-eared owls, monitoring the diet of breeding owls and that of owls at a communal roost, every two to three months during 2006 -2009, in a semi-arid region in Israel. It was found that the studied owls produced m...

  3. Role of radiatively forced temperature changes in enhanced semi-arid warming over East Asia

    Directory of Open Access Journals (Sweden)

    X. Guan

    2015-08-01

    Full Text Available As the climate change occurred over East Asia since 1950s, intense interest and debate have arisen concerning the contribution of human activities to the warming observed in previous decades. In this study, we investigate surface temperature change using a recently developed methodology that can successfully identify and separate the dynamically induced temperature (DIT and radiatively forced temperature (RFT changes in raw surface air temperature (SAT data. For regional averages, DIT and RFT make 43.7 and 56.3 % contributions to the SAT over East Asia, respectively. The DIT changes dominate the SAT decadal variability and are mainly determined by internal climate variability, such as the North Atlantic Oscillation (NAO, Pacific Decadal Oscillation (PDO, and Atlantic Multi-decadal Oscillation (AMO. The radiatively forced SAT changes made major contribution to the global-scale warming trend and the regional-scale enhanced semi-arid warming (ESAW. Such enhanced warming is also found in radiatively forced daily maximum and minimum SAT. The long-term global-mean SAT warming trend is mainly related to radiative forcing produced by global well-mixed greenhouse gases. The regional anthropogenic radiative forcing, however, caused the enhanced warming in the semi-arid region, which may be closely associated with local human activities. Finally, the relationship between global warming hiatus and regional enhanced warming is discussed.

  4. Photosynthesis characteristics and yield of broomcorn millet under film mulching on ridge-furrow for harvesting rainwater model in semi-arid region of Northern Shaanxi%沟垄覆膜集水模式提高糜子光合作用和产量

    Institute of Scientific and Technical Information of China (English)

    苏旺; 屈洋; 冯佰利; 柴岩

    2014-01-01

    The crop productivity is low and unstable in arid and semi-arid region, and water is an important factor limiting crop yield. How to effectively use water and steadily increase crop productivity becomes the focus of attention. Broomcorn millet is one of important crops with large planting area in semi-arid region of Northern Shaanxi, China. In this study, the mechanism of increasing yield under film mulching on ridge-furrow for harvesting rainwater was investigated to provide theoretical support about high yield farming technology of broomcorn millet in arid and semi-arid areas. To explore the effects of film mulching on ridge-furrow for harvesting rainwater on photosynthesis characteristics and yield of broomcorn millet in semi-arid region of Northern Shaanxi, China, a three-year field experiment was conducted with four different widths of ridge and furrow from 2010 to 2012, and the bare land flat sowing as the control (CK). The width of ridge and furrow were 40 cm : 40 cm (P40), 60 cm : 60 cm (P60), 80 cm : 80 cm (P80), and 100 cm : 100 cm (P100), respectively. The field experiment used a randomized block arrangement with three replications. The plant density was 5.0×105 plants/hm2, and the average row spacing was 40 cm. Before sowing, soil preparation, fertilization and film covering had been performed. The organic fertilizer, urea and calcium phosphate were applied in 7 500, 75 and 75 kg/hm2, respectively. The white plastic film used in the experiment was 0.008 mm thick. Net photosynthetic rate, stomatal conductance and intercellular CO2 concentration were measured at 9:00-11:00 am on sunny and windless day, and yield traits were measured in the maturity stage of broomcorn millet. The results showed that film mulching on ridge-furrow for harvesting rainwater could significantly increase the photosynthetic rate and stomatal conductance, and decrease the intercellular CO2 concentration at each growth stage of broomcorn millet. With the increase of ridge and

  5. 半干旱区近地层动量热通量计算%Analysis of momentum and sensible heat fluxes in surface layer in the semi-arid regions

    Institute of Scientific and Technical Information of China (English)

    鲍婧; 张镭; 张燕; 史晋森

    2009-01-01

    By using the tower observation data on wind, temperature, and humidity in the semi-arid climate and environment observatory of Lanzhou University from Dec 2006 to Feb 2007, the friction velocity, friction temperature, turbulent momentum flux and sensible heat flux were analyzed with the gradient calculation method; then the flux value was compared with the result of the eddy-covariance flux measurement in Feb 2007. The results show that the turbulent momentum flux and sensible heat flux have a close connection with the atmospheric stability, and they both decrease with decrease of the stability. They all have obvious diurnal variation, the biggest appears at noon and the smallest at night. The momentum fluxes are always downward transfering regardless of the stability, but sensible heat fluxes are upward transfering at daytime, and downward transfering at night. The monthly mean momentum flux and sensible heat flux are the smallest in Dec, the largest in Feb, and the monthly mean momentum flux is far less than that of the sensible heat flux. In Feb, the slope of turbulent momentum flux scatter diagram is 1.096, and correlation coefficient is 0.761; the slope of sensible heat flux scatter diagram is 1.015, and correlation coefficient is 0.957.%利用兰州大学半干旱气候与环境观测站2006年12月-2007年2月铁塔观测所得的7层风、温、湿资料,采用梯度法计算了摩擦速度、摩擦温度、湍流动量通量和感热通量,并将2007年2月的通量计算值与开路涡度协方差系统观测值进行比较.结果表明:动量通昔和感热通量与稳定度有密切关系.均随稳定度的增加而减小.动量通量和感热通量均有明显的日变化,中午时段最大,夜晚最小.动量通昔无论在何种稳定度条件下均是由上向下输送;感热通量白天均是由下向上输送,夜间均是由上向下输送.在冬季,动量通量和感热通量的月平均值都是在12月最小,在2月最大,且动量通量

  6. 黄土高原干旱半干旱地区气溶胶光学厚度遥感分析%Analyses on Aerosol Optical Depth over Arid and Semi-Arid Region of Loess Plateau Using Remote Sensor Data

    Institute of Scientific and Technical Information of China (English)

    胡蝶; 张镭; 王宏斌

    2013-01-01

    The characteristics of diurnal,monthly change of aerosol optical depth (AOD),and monthly change of Angstrom index (α-index) were analyzed using data of Sun Photometer (CE-318) at the SemiArid Climate and Environment Observatory of Lanzhou University (SACOL) from August 2006 to October 2008,it is found that the amplitude of the diurnal AOD change in spring is larger than that in other seasons,and it shows the double-peak characteristic.AOD is smaller in September and larger in April and December,α-index reaches its minimum in April,and maximum in July.Correlation coefficients of 550 nm AOD retrieved from sun photometer data and that from Terra and Aqua MODIS data are 0.69/0.62.The errors are analyzed from aspects of surface albedo assumption,aerosol model,and influence of clouds.Additionally,Terra and Aqua MODIS data are used for analyzing spatial and seasonal characteristics of AOD above the arid and semi-arid regions of Loess Plateau.Results show that east region has larger AOD,and local maximums are corresponding to capital cities of those provinces.AOD above the arid and semi-arid regions reaches maximum in spring and minimum in autumn.The Deep Blue algorithm for Aqua-MODIS is a good supplement for the retrieval of AOD above bright surface of deserts in Northwest China.%利用兰州大学半干旱气候与环境观测站2006年8月-2008年10月太阳光度计(CE-318)观测资料和同期卫星MODIS(Terra和Aqua)产品资料,分析了该站气溶胶光学厚度(AOD)日变化、月变化和Angstrom波长指数(α指数)月变化特征,发现春季AOD日变幅最大,存在双峰现象,秋、冬季较小;9月AOD最小,4月和12月AOD较大;α指数在4月最小,7月最大.采用太阳光度计反演的550 nm AOD与Terra-MODIS和Aqua-MODIS AOD产品相比较,Terra-MODIS与太阳光度计AOD相关系数为0.69,大于Aqua-MODIS的0.62.并从地表反照率假设、气溶胶模型选择和云影响等方面分析了产生对比偏差的原因,进一步分析了

  7. Remote Sensing Parameterization of Land Surface Heat Fluxes over Arid and Semi-arid Areas

    Institute of Scientific and Technical Information of China (English)

    马耀明; 王介民; 黄荣辉; 卫国安; MassimoMENENTI; 苏中波; 胡泽勇; 高峰; 文军

    2003-01-01

    Dealing with the regional land surfaces heat fluxes over inhomogeneous land surfaces in arid and semi-arid areas is an important but not an easy issue. In this study, one parameterization method based on satellite remote sensing and field observations is proposed and tested for deriving the regional land surface heat fluxes over inhomogeneous landscapes. As a case study, the method is applied to the Dunhuang experimental area and the HEIFE (Heihe River Field Experiment, 1988-1994) area. The Dunhuang area is selected as a basic experimental area for the Chinese National Key Programme for Developing Basic Sciences: Research on the Formation Mecbanism and Prediction Theory of Severe Climate Disaster in China (G1998040900, 1999-2003). The four scenes of Landsat TM data used in this study are 3 June 2000,22 August 2000, and 29 January 2001 for the Dunhuang area and 9 July 1991 for the HEIFE area. The regional distributions of land surface variables, vegetation variables, and heat fluxes over inhomogeneous landscapes in arid and semi-arid areas are obtained in this study.

  8. Application of spatially varying storage capacity model for runoff parameterization in semi-arid catchment

    Institute of Scientific and Technical Information of China (English)

    Li-liang REN; Gui-zuo WANG; Fang LU; Tian-fang FANG

    2009-01-01

    This paper introduces the method of designation of water storage capacity for each grid cell within a catchment, which considers topography, vegetation and soil synthetically. For the purpose of hydrological process simulation in semi-arid regions, a spatially varying storage capacity (VSC) model was developed based on the spatial distribution of water storage capacity and the vertical hybrid runoff mechanism. To verify the applicability of the VSC model, both the VSC model and a hybrid runoff model were used to simulate daily runoff processes in the catchment upstream of the Dianzi hydrological station from 1973 to 1979. The results showed that the annual average Nash-Sutcliffe coefficient was 0.80 for the VSC model, and only 0.67 for the hybrid runoff model. The higher annual average Nash-Sutcliffe coefficient of the VSC model means that this hydrological model can better simulate daily runoff processes in semi-arid regions. Furthermore, as a distributed hydrological model, the VSC model can be applied in regional water resource management.

  9. Semi-arid development: competitiveness factors in biodiesel productive chain

    Directory of Open Access Journals (Sweden)

    Breno Barros Telles do Carmo

    2009-04-01

    Full Text Available The new global market competitiveness considerer the competition between productive chains (PC or supply chains, not just between enterprises. In this case, it can be observed collaboration and cooperation enterprises that dispute with others productives chain. The PC competitiveness can be impaired if is subject by inhibitors factors, that can impairer the performance. This paper analyses these competitiveness factors inhibitors in biodiesel productive chain (CPB in semi-arid area: exported product, market knowledge, competitiveness position, opportunities to aggregate value in chain, cooperation between enterprises, enterprises way of thinking and paternalism by government. It was done this analyses to compare CPB with the world.

  10. Interaction of water components in the semi-arid Huasco and Limarí river basins, North Central Chile

    OpenAIRE

    Strauch, G; R. Oyarzún; F. Reinstorf; J. Oyarzún; M. Schirmer; K. Knöller

    2009-01-01

    For sustainable water resource management in semi-arid regions, sound information is required about interactions between the different components of the water system: rain/snow precipitation, surface/subsurface run-off, groundwater recharge. Exemplarily, the Huasco and Limarí river basins as water stressed river catchments have been studied by isotope and hydrochemical methods for (i) the origin of water, (ii) water quality, (iii) relations of surface and groundwater.

    App...

  11. Detecting soil erosion in semi-arid mediterranean environments using simulated EnMAP data

    Science.gov (United States)

    Bracken, Ashley H.

    Soil is an essential nature resource. Management of this resource is vital for sustainability and the continued functioning of earths atmospheric, hydrospheric and lithospheric functioning. The assessment and continued monitoring of surface soil state provides the information required to effectively manage this resource. This research used a simulated Environmental Mapping and Analysis Program (EnMAP) hyperspectral image cube of an agricultural region in semi- arid Mediterranean Spain to classify soil erosion states. Multiple Endmember Spectral Mixture Analysis (MESMA) was used to derive within pixel fractions of eroded and accumulated soils. A Classification of the soil erosion states using the scene fraction outputs and digital terrain information. The information products generated in this research provided an optimistic outlook for the applicability of the future EnMAP sensor for soil erosion investigations in semi-arid Mediterranean environments. Additionally, this research verifies that the launch of the EnMAP satellite sensor in 2018 will provide the opportunity to further improve the monitoring of earth finite soil resources.

  12. Performance of fenugreek bioinoculated with Rhizobium meliloti strains under semi-arid condition.

    Science.gov (United States)

    Singh, N K; Patel, D B

    2016-01-01

    Rhizobium meliloti strains were isolated from the fields of S.D. Agricultural University (Gujarat, India) and were maintained in the Congo Red Yeast Extract Mannitol Agar medium. These strains were tested for their effectiveness for fenugreek crop grown under semi-arid condition. Among the six Rhizobium strains, FRS-7 strain showed best plant growth parameters like shoot length, shoot dry weight, shoot total nitrogen, root length, root dry weight, root total nitrogen, seed yield, 1000 grain weight, number of root nodules, and nodules fresh and dry weight. The performance of this strain was better as compared to 20 kgN ha(-1) treatment through urea and was even far better over control plot. Seed yields obtained with FRS-7 during two years were 10.14 and 9.66 q ha(-1); which was about 36.8% and 45.9% high over control. This strain resulted in saving of about 20 kgN ha(-1) accompanied with better crop yield and soil health. Results of the present experiments can be utilized in integrated nutrient management for cultivation of fenugreek in semi-arid areas to provide sustainability to agricultural productivity in such regions. PMID:26930857

  13. Groundwater Diffuse Recharge and its Response to Climate Changes in Semi-Arid Northwestern China

    Directory of Open Access Journals (Sweden)

    Lin Deng

    2015-01-01

    Full Text Available Understanding the processes and rates of groundwater recharge in arid and semi-arid areas is crucial for utilizing and managing groundwater resources sustainably. We obtained three chloride profiles of the unsaturated-zone in the desert/loess transition zone of northwestern China and reconstructed the groundwater recharge variations over the last 11, 21, and 37 years, respectively, using the generalized chloride mass balance (GCMB method. The average recharge rates were 43.7, 43.5, and 45.1 mm yr-1, respectively, which are similar to those evaluated by the chloride mass balance (CMB or GCMB methods in other semi-arid regions. The results indicate that the annual recharge rates were not in complete linear proportion to the corresponding annual precipitations, although both exhibited descending tendencies on the whole. Comparisons between the daily precipitation aggregate at different intensity and recharge rates reveal that the occurrence of relatively heavy daily precipitation per year may contribute to such nonlinearity between annual precipitation and recharge. The possible influences of vegetation cover alterations following precipitation change cannot be excluded as well. The approximately negative correlation between the average annual recharge and temperature suggests that changes in temperature have had significant influences on recharge.

  14. Determining erosion and sedimentation chronology on semi-arid catchments using radioisotopes.

    Science.gov (United States)

    Polyakov, Viktor; Nichols, Mary; Nearing, Mark

    2015-04-01

    Semi-arid environment is defined by high magnitude, low frequency rainfalls that produce highly variable soil erosion rates. This study attempted to establish erosion dynamic of past 70 years on three small semi-arid catchments with history of grazing and vegetation change. Activity of Cs-137 and excess Pb-210 from 18 cores collected from sedimentation ponds were measured using gamma spectrometer. The sediment was dated using constant initial concentration (CIC) and constant rate of supply (CRS) models. These estimates were compared with direct measurement of aggradation from historic topographic surveys. Sedimentation in the ponds ranged between 3.1 and 5.4 cm/year and the long term average erosion rates on catchments varied between 0.8 and 1.4 t/ha/year. The distribution of excess Pb-210 in the cores was better described by CRS model. Estimated erosion rates were in agreement with those established by other methods for similar catchments in the region. Past variation in sedimentation rates were identified and correlated with recorded history of grazing, vegetation management, and anthropogenic disturbance. Cs-137 and Pb-210 methods are suitable for use in arid environment and can complement each other to increase reliability of sedimentation rate estimates under highly variable hydrologic regimes.

  15. Richness and distribution of aquatic macrophytes in Brazilian semi-arid aquatic ecosystems Riqueza e distribuição de macrófitas aquáticas em ecossistemas aquáticos do semi-árido brasileiro

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    Gustavo Gonzaga Henry-Silva

    2010-06-01

    Full Text Available AIM: The aim of this study was to evaluate the richness and distribution of the aquatic macrophytes in the basin of the Apodi/Mossoró River, in the semi-arid region (caatinga of Rio Grande do Norte, Brazil; METHODS: A survey of the floristic composition of the aquatic macrophytes was made at 20 sampling stations in the basin at four seasons (August/2007, November/2007, February/2008, May/2008. Specimens of each species were collected and deposited in the Dárdano de Andrade Lima Herbarium of the Universidade Federal Rural do Semi-Árido; RESULTS: We found 40 species of aquatic macrophytes, in 33 genera and 22 families. The families with the most species were Poaceae and Cyperaceae, and the most species-rich genera were Cyperus and Eleocharis. The most common plant form was amphibian (42.5%, followed by emergent (27.5%, free-floating (12.5%, rooted-submersed (10.0%, and floating-leaved (7.5%. The lowest richness was observed at the estuarine region (3 species, and the highest richness in the upper basin (17 species. The rooted-submersed Hydrothrix gardneri Hooker f. and Ceratophyllum demersum L. were observed in great abundance and frequency in the Santa Cruz Reservoir of Apodi, especially in areas close to cage farms of Nile tilapia (Oreochromis niloticus (Linnaeus, 1758. The most common free-floating species were Eichhornia crassipes (Mart. Solms., Pistia stratiotes L., and Salvinia auriculata Aubl., predominantly in stretches that run through urban centers; CONCLUSION: The species richness of aquatic macrophytes in aquatic environments of the caatinga is similar to that observed in other basins of Brazil. Because of the many dams and reservoirs in the semi-arid Northeast, inventory and monitoring of aquatic macrophytes have become essential, especially in basins that will receive water from the diversion of the São Francisco River.OBJETIVO: Nós objetivamos avaliar a riqueza e a distribuição das macrófitas aquáticas nos ambientes aqu

  16. Evaluation of the adaptability of dairy goats in the Brazilian semiarid region with the aid of infrared thermography

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    Elisângela Maria Nunes da Silva

    2014-07-01

    Full Text Available The objective of this study was to evaluate the adaptability of dairy goats with aid of infrared thermography in the environmental conditions of the Brazilian semiarid region. Were used 36 female goats, with a mean of 2.5 years and an average weight of 45 kg, distributed in a completely randomized design 2 x 2 in a factorial arrangement; two genotypes (Anglo Nubian and Alpine Brown and two shifts (morning and afternoon, with 18 repetitions. Analysis of variance showed that the shift had significant effect (P<0.05 on rectal temperature (RT, average surface temperature (AST and thermal gradients, but the breed had no significant effect (P>0.05 and there was no significant interaction between breed and shift. With respect to physiological parameters: respiratory rate (RR and surface temperature of the muzzle of cinnamon there was significant effect of breed and shift and significant interaction between breed and shift (P<0.05. Positive correlations between physiological parameters and room temperature and negative correlation between thermal gradients and more parameters. The Anglo Nubian breed had become more adapted to the semi-arid environmental conditions representing a good alternative for breeding programs. The Alpine breed increased respiratory effort required to dissipate heat and maintain homeothermy, proving to be more demanding regarding system creation and management in the semi-arid climatic conditions.

  17. Economic valuation of sheep genetic resources: implications for sustainable utilization in the Kenyan semi-arid tropics.

    Science.gov (United States)

    Omondi, I; Baltenweck, I; Drucker, A G; Obare, G; Zander, K K

    2008-12-01

    Sheep, recognised as one of the important livestock species especially in the semi-arid tropics with high genetic resource potentials, can be exploited through sustainable utilization in order to improve livestock keepers' livelihoods. This study presents the evaluation of the economic values of sheep genetic resources (SGR) in terms of the important non-market traits embedded in sheep and how this information can be utilised to improve livelihoods in semi-arid regions. The results obtained from mixed logit models results derived from stated choice data collected from 157 respondents in the semi-arid Marsabit district of Kenya reveal that disease resistance is the most highly valued trait whose resultant increment results into a welfare improvement of up to KShs.1537. Drought tolerance and fat deposition traits were found to be implicitly valued at KShs.694 and 738 respectively. The results further point out that for livestock stakeholders to effectively improve the livelihoods of poor livestock-keepers, development strategies for improving the management and/or utilisation of SGR in terms of drought tolerance, should not only be tailor made to target regions that are frequently devastated by drought but should also succeed other strategies or efforts that would first lead to the improvement of producers' economic status.

  18. Introdução e seleção de espécies arbóreas forrageiras exóticas na região semi-árida do Estado de Sergipe Introduction and selection of arboreal forage species in the semi-arid region of Sergipe State

    Directory of Open Access Journals (Sweden)

    Marcos Antônio Drumond

    1999-12-01

    Sergipe, Brazil. Fifteen species from the semi-arid area of Central America were introduced in the region: Acacia farnesiana, Albizia caribaea, Albizia guachepele, Ateleia herbert-smithii, Caesalpinia coriaria, Caesalpinia eryostachys, Caesalpinia velutina, Enterolobium cyclocarpum, Gliricidia sepium, Leucaena diversifolia, Leucaena leucocephala, Leucaena shannoni, Parkinsonia aculeata, Pithecellobium dulce and Senna otomaria. The species were planted in the Experimental Field of Glória, Embrapa Semi-Árido, in Nossa Senhora da Glória, Sergipe State, in holes of 30cmx30cm, without fertilization, 3.0mx2.0m apart in a randomized block design with three replications and 36 plants per plot. They were evaluated for survival, height, diameter at the height of 1.30m from the soil surface, 55 months after planting. G. sepium and A. guachepelle showed higher growth than the other species, with mean heights (± standard deviation, of 4.0±0.4 and 4.3±0.2m respectively, and mean diameters (± standard deviation of 4.4±0.5 and 6.3±0.1cm, and survival rates of 100 and 98%. Although L. leucocephala showed excellent growth in height (5.0±0.3m and in diameter (6.0±1.5cm, its survival rate was 44%. L. diversifolia and A. farnesiana have shown 100% mortality in the studied plots. Gliricidia sepium and Albizia guachepele were outstanding, with great potentiality for the semi-arid areas in the State of Sergipe. Acacia farnesiana, Leucaena diversifolia and Senna otomaria did not show a good performance in the semi-arid conditions of the region.

  19. Seasonal dynamics of soil CO2 efflux in biodiverse semi-arid ecosystems of Western Australia

    Science.gov (United States)

    Muñoz-Rojas, Miriam; Lewandrowski, Wolfgang; Martini, Dylan; Erickson, Todd; Merritt, David; Dixon, Kingsley

    2015-04-01

    Introduction In recent years, soil respiration (Rs) has been a major research focus given the increase in atmospheric CO2 emissions and the large contribution of CO2 fluxes from soils. Rs is the second largest carbon flux in terrestrial ecosystems and globally accounts for 98±12 CO2-C yr-1 or ten times that produced by fossil fuel combustion. In addition to its importance in the global carbon cycle, Rs is a key indicator of ecosystem state and functioning. Despite the global importance of this process, there is still limited knowledge of its and responses to abiotic and biotic processes, particularly in arid and semi-arid areas. In this research we investigated the seasonal variations and controlling factors of Rs for different vegetation types in biodiverse ecosystems of the Pilbara region (Western Australia). This region, with a semi-arid climate and two main seasons (wet-summer and dry-winter), is an ancient landscape with diverse geology and high levels of regional endemism. Methods This research was conducted in seven study sites across the Pilbara region with similar native soils and analogous ecosystems representative of the area. A permanent plot was defined at each site which included three of the most representative and dominant vegetation cover types of the Pilbara ecosystems: trees (Corymbia spp.), shrubs (Acacia spp.), grasses (Triodia spp.), and bare soil. Soil sampling and field measurements were carried out in February 2014 (wet-summer season) and July 2014 (dry-winter season). Rs was measured with a portable soil CO2 flux chamber attached to a Li-Cor 6400 and, simultaneously, both temperature and soil moisture were determined. Results Soil CO2 efflux ranged from 0.57 µmol m-2 s-1 to 1.96 µmol m-2 s-1 in the dry-winter season and from 1.57 µmol m-2 s-1 to 3.91 µmol m-2 s-1 in the wet-summer season. Higher Rs rates were found in the wet-summer season in all vegetation types and below Corymbia spp. in both periods. Rs differed significantly

  20. Hydrologic feasibility of artificial forestation in the semi-arid Loess Plateau of China

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    T. T. Jin

    2011-08-01

    Full Text Available Hydrologic viability, in terms of moisture availability, is fundamental to ecosystem sustainability in arid and semi-arid regions. In this study, we examine the spatial distribution and after-planting variations of soil moisture content (SMC in black locust tree (Robinia pseudoacacia L. plantings in the Loess Plateau of China at a regional scale. Thirty sites (5 to 45 yr old were selected, spanning an area of 300 km by 190 km in the northern region of the Shaanxi Province. The SMC was measured to a depth of 100 cm at intervals of 10 cm. Geographical, topographic and vegetation information was recorded, and soil organic matter was evaluated. The results show that, at the regional scale, SMC spatial variability was most highly correlated with rainfall. The negative relationship between the SMC at a depth of 20–50 cm and the stand age was stronger than at other depths, although this relationship was not significant at a 5 % level. Watershed analysis shows that the after-planting SMC variation differed depending upon precipitation. The SMC of plantings in areas receiving sufficient precipitation (e.g., mean annual precipitation (MAP of 617 mm may increase with stand age due to improvements in soil water-holding capacity and water-retention abilities after planting. For areas experiencing water shortages (e.g., MAP = 509 mm, evapotranspiration may cause planting soils to dry within the first 20 yr of growth. It is expected that, as arid and semi-arid plantings age, evapotranspiration will decrease, and the soil profile may gradually recover. In extremely dry areas (e.g., MAP = 352 mm, the variation in after-planting SMC with stand age was found to be negligible. The MAP can be used as an index to divide the study area into different ecological regions. Afforestation may sequentially exert positive, negative and negligible effects on SMCs with a decrease in the MAP. Therefore, future restoration measures should correspond to the local climate

  1. Stem Biomass Production of Paulownia elongata × P. fortunei under Low Irrigation in a Semi-Arid Environment

    Directory of Open Access Journals (Sweden)

    Francisco Antonio García-Morote

    2014-10-01

    Full Text Available In semi-arid regions, afforestation with fast-growing species cultured with low irrigation can be an effective approach for environmental protection. An experiment was conducted to evaluate the stem biomass production of Paulownia in a semi-arid climate and clay soils under contrasting low-irrigation and fertilization treatments. The stem biomass at the stand level was estimated by applying allometric equations fitted in sample resprouts and inventory data. The results show that biomass production improved when either irrigation or fertilizer was added, but the combination of a higher dose of irrigation and fertilization did not lead to the highest biomass production; thus water availability was the main factor controlling biomass production. Under the higher dose of irrigation, the absence of a fertilizer effect would be due in part to the fertile soil, which could supply sufficient nutrients for Paulownia growth at the higher level of soil moisture. The stem biomass estimated ranged from 2.14 to 4.50 t×ha−1 (lower irrigation dose without fertilization, and higher irrigation with fertilization. The greater production was similar to other studies in the Mediterranean area receiving more irrigation. Thus, this study permitted us to understand the potential of Paulownia to provide biomass in semi-arid environments with low irrigation due to water use restrictions.

  2. Management implications of the ecology of free-roaming horses in semi-arid ecosystems of the western United States

    Science.gov (United States)

    Beever, Erik A.

    2003-01-01

    Compared to other ungulates of North America, free-roaming horses (Equus caballus) possess a unique evolutionary history that has given rise to a distinct suite of behavioral, morphological, and physiological traits. Because of their unique combination of cecal digestion, an elongate head with flexible lips, and non-uniform use of the landscape, horses represent a unique disturbance agent in semi-arid ecosystems of the western United States. Consequently, it is inappropriate to assume that influences of horses on the structure, composition, function, and pattern of arid and semi-arid ecosystems will mirror influences of cattle or other artiodactyls. Although management areas for free-roaming horses occupy 18.6 million ha of land across western North America, we know relatively little about how western ecosystems and their components have responded to this uniquely managed ungulate. I draw on my research of horse habitats in the western Great Basin (U.S.A.) to examine predictions of horses' unique influence, and advocate for continued research to refine our understanding of synecological relationships among horses and diverse ecosystem components in arid and semi-arid regions.

  3. Effects of legume cover crop and sub-soiling on soil properties and Maize (Zea mays L) growth in semi arid area of Machakos district, Kenya = Efecto del cultivo de cobertua y el subsolado sobre las propiedades del suelo y crecimiento de maiz (Zea mays L.) en la region semi arida de Machakos, Kenia

    NARCIS (Netherlands)

    Karuma, A.; Gachene, C.K.K.; Gicheru, P.; Mwangombe, A.W.; Mwangi, H.W.; Clavel, D.; Verhagen, A.; Kaufmann, Von R.; Francis, J.; Ekaya, W.

    2011-01-01

    Low crop yields in the semi arid areas of Kenya have been attributed to, among other factors, low soil fertility, low farm inputs, labour constraints and inappropriate tillage practices that lead to pulverized soils. The aim of this study was to determine the effects of legume cover crops (LCC) on s

  4. Soil biogenic emissions of nitric oxide from a semi-arid savanna in South Africa

    Science.gov (United States)

    Feig, G. T.; Mamtimin, B.; Meixner, F. X.

    2008-12-01

    Soils of arid and semi-arid ecosystems are important biogenic sources of atmospheric nitric oxide (NO), however, there is still a shortage of measurements from these systems. Here we present the results of a laboratory study of the biogenic emission of NO from four different landscape positions of the Kruger National Park (KNP), a large conservation area in a semi-arid region of South Africa. Results show that the highest net potential NO fluxes come from the low lying (footslope) landscape regions, which have the largest nitrogen stocks and highest rates of nitrogen input into the soil. Net potential NO fluxes from midslope and crest regions were considerably lower. The maximum release of NO occurred at fairly low soil moisture contents of 10%-20% water filled pore space. Using soil moisture and temperature data obtained in situ at the Kruger National Park flux tower site, net potential NO fluxes obtained in the laboratory were converted to field fluxes for each of the four landscape positions for the period 2003 to 2005. The highest field NO flux is from footslope positions, during each of these years and emissions ranged from 1.5-8.5 kg ha a (in terms of mass of nitrogen). Remote sensing and Geographic Information Systems techniques were used to up-scale field NO fluxes on a regional basis indicating that the highest emissions occurred from the midslope positions, due to their large geographical extent in the considered research area. Emissions for the KNP Skukuza land type (56 000 ha) ranged from 20×103 kg in 2004 to 34×103 kg in 2003. The importance of landscape characteristics in the determination of regional biogenic NO soil emission is emphasized.

  5. Understanding runoff processes in a semi-arid environment through isotope and hydrochemical hydrograph separations

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    V. V. Camacho

    2015-01-01

    Full Text Available The understanding of runoff generation mechanisms is crucial for the sustainable management of river basins such as the allocation of water resources or the prediction of floods and droughts. However, identifying the mechanisms of runoff generation has been a challenging task, even more so in arid and semi-arid areas where high rainfall and streamflow variability, high evaporation rates, and deep groundwater reservoirs increase the complexity of hydrological process dynamics. Isotope and hydrochemical tracers have proven to be useful in identifying runoff components and their characteristics. Moreover, although widely used in humid-temperate regions, isotope hydrograph separations have not been studied in detail in arid and semi-arid areas. Thus the purpose of this study is to determine if isotope hydrograph separations are suitable for the quantification and characterization of runoff components in a semi-arid catchment considering the hydrological complexities of these regions. Through a hydrochemical characterization of the surface water and groundwater sources of the catchment and two and three component hydrograph separations, runoff components of the Kaap Catchment in South Africa were quantified using both, isotope and hydrochemical tracers. No major disadvantages while using isotope tracers over hydrochemical tracers were found. Hydrograph separation results showed that runoff in the Kaap catchment is mainly generated by groundwater sources. Two-component hydrograph separations revealed groundwater contributions between 64 and 98% of total runoff. By means of three-component hydrograph separations, runoff components were further separated into direct runoff, shallow and deep groundwater components. Direct runoff, defined as the direct precipitation on the stream channel and overland flow, contributed up to 41% of total runoff during wet catchment conditions. Shallow groundwater defined as the soil water and near-surface water component

  6. Large-scale transcriptome analysis in chickpea (Cicer arietinum L.), an orphan legume crop of the semi-arid tropics of Asia and Africa

    Science.gov (United States)

    Chickpea (Cicer arietinum L.) is an important legume crop in the semi-arid regions of Asia and Africa. Gains in crop productivity have been low however, particularly due to biotic and abiotic stresses. To help enhance crop productivity using molecular breeding techniques, next generation sequencing ...

  7. Surficial weathering of iron sulfide mine tailings under semi-arid climate

    Science.gov (United States)

    Hayes, Sarah M.; Root, Robert A.; Perdrial, Nicolas; Maier, Raina; Chorover, Jon

    2014-01-01

    Mine wastes introduce anthropogenic weathering profiles to the critical zone that often remain unvegetated for decades after mining cessation. As such, they are vulnerable to wind and water dispersion of particulate matter to adjacent ecosystems and residential communities. In sulfide-rich ore tailings, propagation to depth of the oxidative weathering front controls the depth-variation in speciation of major and trace elements. Despite the prevalence of surficial mine waste deposits in arid regions of the globe, few prior studies have been conducted to resolve the near-surface profile of sulfide ore tailings weathered under semi-arid climate. We investigated relations between gossan oxidative reaction-front propagation and the molecular speciation of iron and sulfur in tailings subjected to weathering under semi-arid climate at an EPA Superfund Site in semi-arid central Arizona (USA). Here we report a multi-method data set combining wet chemical and synchrotron-based X-ray diffraction (XRD) and X-ray absorption near-edge spectroscopy (XANES) methods to resolve the tight coupling of iron (Fe) and sulfur (S) geochemical changes in the top 2 m of tailings. Despite nearly invariant Fe and S concentration with depth (130–140 and 100–120 g kg−1, respectively), a sharp redox gradient and distinct morphological change was observed within the top 0.5 m, associated with a progressive oxidative alteration of ferrous sulfides to (oxyhydr)oxides and (hydroxy)sulfates. Transformation is nearly complete in surficial samples. Trends in molecular-scale alteration were co-located with a decrease in pH from 7.3 to 2.3, and shifts in Fe and S lability as measured via chemical extraction. Initial weathering products, ferrihydrite and gypsum, transform to schwertmannite, then jarosite-group minerals with an accompanying decrease in pH. Interestingly, thermodynamically stable phases such as goethite and hematite were not detected in any samples, but ferrihydrite was observed even

  8. Surficial weathering of iron sulfide mine tailings under semi-arid climate.

    Science.gov (United States)

    Hayes, Sarah M; Root, Robert A; Perdrial, Nicolas; Maier, Raina; Chorover, Jon

    2014-09-15

    Mine wastes introduce anthropogenic weathering profiles to the critical zone that often remain unvegetated for decades after mining cessation. As such, they are vulnerable to wind and water dispersion of particulate matter to adjacent ecosystems and residential communities. In sulfide-rich ore tailings, propagation to depth of the oxidative weathering front controls the depth-variation in speciation of major and trace elements. Despite the prevalence of surficial mine waste deposits in arid regions of the globe, few prior studies have been conducted to resolve the near-surface profile of sulfide ore tailings weathered under semi-arid climate. We investigated relations between gossan oxidative reaction-front propagation and the molecular speciation of iron and sulfur in tailings subjected to weathering under semi-arid climate at an EPA Superfund Site in semi-arid central Arizona (USA). Here we report a multi-method data set combining wet chemical and synchrotron-based X-ray diffraction (XRD) and X-ray absorption near-edge spectroscopy (XANES) methods to resolve the tight coupling of iron (Fe) and sulfur (S) geochemical changes in the top 2 m of tailings. Despite nearly invariant Fe and S concentration with depth (130-140 and 100-120 g kg(-1), respectively), a sharp redox gradient and distinct morphological change was observed within the top 0.5 m, associated with a progressive oxidative alteration of ferrous sulfides to (oxyhydr)oxides and (hydroxy)sulfates. Transformation is nearly complete in surficial samples. Trends in molecular-scale alteration were co-located with a decrease in pH from 7.3 to 2.3, and shifts in Fe and S lability as measured via chemical extraction. Initial weathering products, ferrihydrite and gypsum, transform to schwertmannite, then jarosite-group minerals with an accompanying decrease in pH. Interestingly, thermodynamically stable phases such as goethite and hematite were not detected in any samples, but ferrihydrite was observed even in

  9. Coupled flow and salinity transport modelling in semi-arid environments

    DEFF Research Database (Denmark)

    Bauer-Gottwein, Peter; Held, R.J.; Zimmermann, S.;

    2006-01-01

    and transpirative salt enrichment. An existing numerical code for coupled flow/transport simulations (SEAWAT) was adapted to this situation. Model results were checked against a large set of field data including water levels, water chemistry, isotope data and ground and airborne geophysical data. The resulting......Numerical groundwater modelling is used as the base for sound aquifer system analysis and water resources assessment. In many cases, particularly in semi-arid and arid regions, groundwater flow is intricately linked to salinity transport. A case in point is the Shashe River Valley in Botswana....... A freshwater aquifer located around an ephemeral stream is depleted by the combined effect of transpiration and pumping. Quantitative system analysis reveals that the amount of water taken by transpiration is far more than the quantities pumped for water supply. Furthermore, the salinity distribution...

  10. Transfer of 137Cs in Zea mays and Phaseolus vulgaris in a semi-arid ecosystem

    International Nuclear Information System (INIS)

    With the objective to analyse the transference of 137 Cs from soil to plants, it is realized a study in maize and bean plants in the Radioactive Waste Storage Center (CADER). This site is located in a semi-arid region with a characteristic vegetation of a sub humid temperature zone. So those plants maize and beans were cultivated in four zones near CADER during a four years period. The obtained results for 1991 to 1994 for 137 Cs in soil samples for those zones showed an evident contamination in zone 1, due to a rupture of an industrial source. In 1994 the effect of decontamination was evident since the values of specific activity found in roots were around magnitude lesser than found in 1992. In spite of exhaustive studies have been reported about the transference factors for 137 Cs in different agricultural foods, relatively few of them have paid attention to the interactions between cereals and leguminous associated in semiarid ecosystems. (Author)

  11. Prevalência e determinantes de obesidade e sobrepeso em mulheres em idade reprodutiva residentes na região semiárida do Brasil Prevalence and determinants of obesity and overweight among reproductive age women living in the semi-arid region of Brazil

    Directory of Open Access Journals (Sweden)

    Luciano Lima Correia

    2011-01-01

    Full Text Available O estudo estimou a prevalência e identificou fatores determinantes do sobrepeso e obesidade em mulheres em idade fértil na região semiárida do Brasil. Na amostra por conglomerados de oito mil domicílios do estado do Ceará, foram pesquisadas 6.845 mulheres. Sobrepeso e obesidade foram medidos pelo Índice de Massa Corporal, utilizando-se a análise multivariada para a identificação dos fatores determinantes. As prevalências de sobrepeso e obesidade foram de 32,6% e 16,1%, respectivamente. Na análise ajustada, a obesidade esteve positivamente associada a: idade >30 anos (RP=1,55, estado civil casada (RP=1,36, escolaridade fundamental (RP=1,40, idade na menarca 1 filho (RP=1,65, uso de contraceptivos (RP=1,31. Os fatores relacionados à saúde e à nutrição, referentes à obesidade mórbida, foram: hipertensão arterial (RP=3,11, diabetes (RP=2,08, insatisfação com a imagem corporal (RP=4,26 e procedimentos para perder peso (RP=2,73. Sobrepeso e obesidade são altamente prevalentes na região semiárida. A educação foi o único fator socioeconômico passível de ser modificado. Os fatores reprodutivos identificados apontam para a necessidade de mobilização dos serviços de pré-natal, pós-parto e planejamento familiar na prevenção e no controle da obesidade.The study estimated the prevalence and determinants of overweight and obesity in women of reproductive age in the Semi-Arid Region of Brazil. In the cluster sampling of 8,000 households of the state of Ceará, 6,845 women were surveyed. Overweight and obesity were measured by the body mass index and risk factors identified by multivariate analysis. The prevalences of overweight and obesity were 32.6% and 16.1%, respectively. After adjusted analysis, obesity was positively associated with age >30 years (PR = 1.55, marital status, married (PR = 1.36, elementary education (PR = 1.40, age at menarche 1 child (PR = 1.65 and contraceptive use (PR = 1.31. Specific health and

  12. Comportamento de seis variedades de pomelo (Citrus paradisi Macfad. cultivadas sob irrigação na região semi-árida de Pernambuco Behavior of six grapefruit varieties grown under irrigation at the semi-arid region of Pernambuco - Brazil

    Directory of Open Access Journals (Sweden)

    Ildo Eliezer Lederman

    2005-08-01

    Full Text Available O uso da irrigação nas regiões semi-áridas do Nordeste brasileiro tem viabilizado o cultivo comercial de inúmeras fruteiras, tais como a uva, a manga, a goiaba, o coco e a banana. Outras espécies, como o pomelo, ou grapefruit, vêm sendo ainda objeto de estudos e avaliações. Uma coleção formada de 06 variedades de pomelos (Citrus paradisi, de polpas com coloração rosa-avermelhada ('Marsh Foster', 'Star Ruby', 'Rio Red' e 'Red Blush' e amarelada ('Triumph' e 'Marsh Foster Nucelar', foi implantada em 1993 na Estação Experimental de Ibimirim, localizada no município de Ibimirim, no Vale do Rio Moxotó - região semi-árida de Pernambuco. Contando com cinco plantas por parcela, a coleção foi conduzida sob irrigação localizada e as avaliações realizadas durante três anos (2000 a 2002. Os resultados demostraram alta variabilidade na produção de frutos, tendo a variedade 'Marsh Foster Nucelar' alcançado a produção média de 135,0 kg/planta, enquanto a 'Star Ruby' atingiu apenas 31,0 kg/planta. O peso médio dos frutos variou de 285,5g ('Red Blush' até um máximo de 401,6g na variedade 'Triumph'. O volume de suco extraído, os sólidos solúveis totais (SST, a acidez total titulável (ATT e a relação SSS/ATT também apresentaram mudanças entre as variedades estudadas.The use of irrigation at the semi-arid region of Northeast Brazil has made feasible several commercial fruit trees crops such as grapevines, mango, guava, coconut, banana and others, like grapefruit, which actually is being studied. A collection formed by six grapefruit varieties showing a pink-red pulp color (Marsh Foster, Star Ruby, Rio Red and Red Blush and a creamy color (Triumph and Marsh Foster Nucelar and consisting of five plants/plot was installed in 1993 at the Ibimirim Experimental Station, located in the Moxotó river valley at the semi-arid region of Pernambuco - Northeast Brazil, under irrigation. Evaluations carried out during three years (from

  13. Distributed Hydrological Modeling in Semi-Arid Region in Northeast China:A Case Study in the Taoer River Basin%东北半干旱地区流域分布式水文模拟——以洮儿河流域为例

    Institute of Scientific and Technical Information of China (English)

    尹雄锐; 章光新; 杨帆; 许斌

    2011-01-01

    This study takes Taoer River basin, a typical basin in semi-arid region of Northeast China, as study area, and simulates its hydrological process by the soil and water assessment tool (SWAT) model. Parameter sensitivity analysis is carried out on the upper sub-basin and middle-lower sub-basin to identify the sensitive parameters affecting stream flow. Results show spatial heterogeneity of several parameters' sensitivities, and the reason is the difference of runoff generating mode caused by spatial heterogeneities of climate and underlying surface. Calibration and verification of hydrological model are carried out by daily hydrological and meteorological data from 1988 to 1997, and the results show that average Nash-Sutcliffe efficiency coefficient (EC) of monthly runoff simulation at main stream gauging stations is 0.78 for calibration period and 0.72 for verification period, relative coefficient is more than 0.86, relative error of water budget is within 20%, and daily runoff simulation is also fairly good;while the simulation is not satisfied for dry period due to the inadequacy of precipitation gauging station to capture spatial and temporal distribution of precipitation. These researches show the applicability of SWAT model in modeling runoff generation and relative hydrological process in semi-arid region in Northeast China with scarce-data, and meanwhile it provides foundation and tool for improving further study in water resources integrated management of Taoer River basin.%以东北半干旱地区典型流域--洮儿河流域为研究对象,应用SWAT模型对流域水文过程进行了模拟研究;选择流域上游子流域和中下游子流域分别进行参数敏感性分析,识别出影响模拟结果的敏感参数,研究发现部分参数敏感性存在空间变异性,分析主要原因在于气候和下垫面的空间异质性导致了流域上下游产流模式存在差异.采用1988-1997年水文气象数据进行模型率定

  14. Implementation of a 3-D groundwater flow model in a semi-arid region using MODFLOW and GIS tools : The Zeramdine-Beni Hassen Miocene aquifer system (east-central Tunisia)

    OpenAIRE

    Lachaal, F.; Mlayah, A; Bedir, M.; Tarhouni, J.; Leduc, Christian

    2012-01-01

    In this work, an integrated methodology was developed to investigate hydrological processes in Zeramdine-Beni Hassen Miocene aquifer and to validate the groundwater proprieties deduced from the geological, geophysical, hydrodynamic and hydrochemical studies done in the region, using the coupling of groundwater flow model MODFLOW 2000 code with Geographic Information System tools. A 3-D groundwater flow model was developed for this aquifer using a large amount of available geological and hydro...

  15. Quantifying the thermal heat requirement of Brassica in assessing biophysical parameters under semi-arid microenvironments

    Science.gov (United States)

    Adak, Tarun; Chakravarty, N. V. K.

    2010-07-01

    Evaluation of the thermal heat requirement of Brassica spp. across agro-ecological regions is required in order to understand the further effects of climate change. Spatio-temporal changes in hydrothermal regimes are likely to affect the physiological growth pattern of the crop, which in turn will affect economic yields and crop quality. Such information is helpful in developing crop simulation models to describe the differential thermal regimes that prevail at different phenophases of the crop. Thus, the current lack of quantitative information on the thermal heat requirement of Brassica crops under debranched microenvironments prompted the present study, which set out to examine the response of biophysical parameters [leaf area index (LAI), dry biomass production, seed yield and oil content] to modified microenvironments. Following 2 years of field experiments on Typic Ustocrepts soils under semi-arid climatic conditions, it was concluded that the Brassica crop is significantly responsive to microenvironment modification. A highly significant and curvilinear relationship was observed between LAI and dry biomass production with accumulated heat units, with thermal accumulation explaining ≥80% of the variation in LAI and dry biomass production. It was further observed that the economic seed yield and oil content, which are a function of the prevailing weather conditions, were significantly responsive to the heat units accumulated from sowing to 50% physiological maturity. Linear regression analysis showed that growing degree days (GDD) could indicate 60-70% variation in seed yield and oil content, probably because of the significant response to differential thermal microenvironments. The present study illustrates the statistically strong and significant response of biophysical parameters of Brassica spp. to microenvironment modification in semi-arid regions of northern India.

  16. Uso e qualidade da água subterrânea para irrigação no semi-árido piauiense Use and quality of groundwater for irrigation in semi-arid region of the Piauí State, Brazil

    Directory of Open Access Journals (Sweden)

    Aderson S. de Andrade Júnior

    2006-12-01

    Full Text Available A região semi-árida do Estado do Piauí é caracterizada por baixa intensidade pluviométrica e elevadas taxas de evapotranspiração. Porém a reserva de água subterrânea torna possível o desenvolvimento de atividades antrópicas, potencializada, na maioria dos casos, pelas características hidrogeológicas do subsolo, que permitem explotações de alta vazão de água com boa qualidade; todavia, alguns poços atingem formações de baixa vazão e qualidade de água com concentração de sais elevada e que, se utilizada para irrigação, pode ocasionar a salinização e a sodificação dos solos. Dessa forma, objetivou-se caracterizar as formas de uso e a qualidade das águas subterrâneas em parte da região semi-árida do Piauí, visando ao seu uso para irrigação. Coletaram-se amostras em 225 poços distribuídos espacialmente, nas quais foram analisadas as seguintes variáveis: condutividade elétrica, sódio, cálcio, magnésio, relação de adsorção de sódio, carbonato, bicarbonato, cloreto e sulfato. Em relação ao uso da água, predominou o uso doméstico (53,61%, seguido pela irrigação (21,17%, com os seguintes métodos: gotejamento (14,03%; microaspersão (3,83%; aspersão convencional (16,11%; canhão e autopropelido (13,66%; superfície (16,76% e outros métodos artesanais (35,52%. Os mapas de classes de risco de uso para irrigação, gerados a partir da qualidade da água subterrânea, evidenciam a ocorrência de sub-áreas com as seguintes classes: nenhuma restrição, moderada restrição e severa restrição.The semi-arid region in the State of Piauí, Brazil, is characterized by low rain fall and high evapotranspiration. However, the groundwater reserves make possible the economic development by underground hydrogeology characteristics, which allow extractions of high water flow with good quality, in most of the cases. However, some wells reached formations that have low discharge and water with high salt

  17. Were Semi-Arid Areas Wetter or Drier during the Pliocene?

    Science.gov (United States)

    Feakins, S. J.; Liddy, H.; Tierney, J. E.

    2014-12-01

    Drying is projected for many semi-arid areas under global warming scenarios. The Pliocene provides a natural analog for global warmth, allowing us to test the terrestrial response to past warming. Today North East Africa (O to 12 N, 38 to 50 E) includes C3 shrubs in arid areas, C4 grasslands in semi-arid areas and C3 trees in the moister uplands. Here we take a biomarker approach to reconstructing terrestrial vegetation and hydrological changes in NE Africa during the Pliocene and develop complementary records of sea surface temperature (SST) changes in the Western Indian Ocean. We find the plant leaf wax carbon isotopic negative anomaly to be ambiguous. Woody cover interpretations suggest afforestation with C3 trees. But an alternative explanation, an increase of dry C3 shrublands, appears more likely based on drying evidence from hydrogen isotopes and pollen for an expansion of shrub taxa. Either change implies a contraction of the Miocene C4 grasslands. To explore the mechanisms for drying we look to the Western Indian Ocean and find biomarker trends show a coincident cooling (in contrast to Mg/Ca), providing a mechanism to reduce moisture supply to the continent. We are adding to the resolution and coverage of the d13C, dD, pollen and TEX86 records in order to assess whether this Pliocene scenario is robust. Specifically we are testing the hypothesis that a cooling trend in the Western Indian Ocean is coincident with a drying and C3 shrubland expansion. Our work to resolve these quite different scenarios (afforestation or aridification on land) is key, since model simulations have offered up both wetter and drier regional responses to Pliocene global warmth and questions about the direction of SST changes (warming or cooling Indian Ocean across the Pliocene) forms part of the larger present debate about the fidelity of Pliocene SST proxies.

  18. Modeling mechanisms of vegetation change due to fire in a semi-arid ecosystem

    Science.gov (United States)

    White, J.D.; Gutzwiller, K.J.; Barrow, W.C.; Randall, L.J.; Swint, P.

    2008-01-01

    Vegetation growth and community composition in semi-arid environments is determined by water availability and carbon assimilation mechanisms specific to different plant types. Disturbance also impacts vegetation productivity and composition dependent on area affected, intensity, and frequency factors. In this study, a new spatially explicit ecosystem model is presented for the purpose of simulating vegetation cover type changes associated with fire disturbance in the northern Chihuahuan Desert region. The model is called the Landscape and Fire Simulator (LAFS) and represents physiological activity of six functional plant types incorporating site climate, fire, and seed dispersal routines for individual grid cells. We applied this model for Big Bend National Park, Texas, by assessing the impact of wildfire on the trajectory of vegetation communities over time. The model was initialized and calibrated based on landcover maps derived from Landsat-5 Thematic Mapper data acquired in 1986 and 1999 coupled with plant biomass measurements collected in the field during 2000. Initial vegetation cover change analysis from satellite data showed shrub encroachment during this time period that was captured in the simulated results. A synthetic 50-year climate record was derived from historical meteorological data to assess system response based on initial landcover conditions. This simulation showed that shrublands increased to the detriment of grass and yucca-ocotillo vegetation cover types indicating an ecosystem-level trajectory for shrub encroachment. Our analysis of simulated fires also showed that fires significantly reduced site biomass components including leaf area, stem, and seed biomass in this semi-arid ecosystem. In contrast to other landscape simulation models, this new model incorporates detailed physiological responses of functional plant types that will allow us to simulated the impact of increased atmospheric CO2 occurring with climate change coupled with fire

  19. When does colonisation of a semi-arid hillslope generate vegetation patterns?

    Science.gov (United States)

    Sherratt, Jonathan A

    2016-07-01

    Patterned vegetation occurs in many semi-arid regions of the world. Most previous studies have assumed that patterns form from a starting point of uniform vegetation, for example as a response to a decrease in mean annual rainfall. However an alternative possibility is that patterns are generated when bare ground is colonised. This paper investigates the conditions under which colonisation leads to patterning on sloping ground. The slope gradient plays an important role because of the downhill flow of rainwater. One long-established consequence of this is that patterns are organised into stripes running parallel to the contours; such patterns are known as banded vegetation or tiger bush. This paper shows that the slope also has an important effect on colonisation, since the uphill and downhill edges of an isolated vegetation patch have different dynamics. For the much-used Klausmeier model for semi-arid vegetation, the author shows that without a term representing water diffusion, colonisation always generates uniform vegetation rather than a pattern. However the combination of a sufficiently large water diffusion term and a sufficiently low slope gradient does lead to colonisation-induced patterning. The author goes on to consider colonisation in the Rietkerk model, which is also in widespread use: the same conclusions apply for this model provided that a small threshold is imposed on vegetation biomass, below which plant growth is set to zero. Since the two models are quite different mathematically, this suggests that the predictions are a consequence of the basic underlying assumption of water redistribution as the pattern generation mechanism. PMID:26547308

  20. Heterogeneous aquifer system modelisation under semi-arid climate

    Science.gov (United States)

    Drias, Tarek; Toubal, Ahmed Cherif

    2010-05-01

    The studied zone is a part of the Mellegne's (North-East of Algeria) under pound, this zone is characterised by its semi-arid climate. The water bearing system is formed by the plio-quaternairy alluviums resting on a marley substratuim of age Eocene. The geostatiscitcs approach of the hydrodynamics parameters (Hydrolic load, transmisivity) allowed the study of their spatial distrubution (casting) by the method of Krigeage by blocks and the identification of zones with water-bearing potentialities. In this respect, the zone of Ain Chabro which, is situated in the South of the plain shows the best values of the transmisivity...... The use of a bidimensinnel model in the differences ended in the permanent regime allowed us to establish the global balence sheet (overall assessment) of the tablecloth and to refine the transmisivity field. These would vary more exactley between 10-4 to 10-2 m²/s. The method associating the probability appraoch of Krigeage to that determining the model has facilited the wedging of the model and clarified the inflitration value. Keys words: hydrodynamics, geostatiscitcs, Modeling, Chabro, Tébessa.

  1. Antiproliferative Activity, Antioxidant Capacity and Tannin Content in Plants of Semi-Arid Northeastern Brazil  

    Directory of Open Access Journals (Sweden)

    Silene Carneiro do Nascimento

    2010-11-01

    Full Text Available The objective of this study was to evaluate antiproliferative activity, antioxidant capacity and tannin content in plants from semi-arid northeastern Brazil (Caatinga. For this study, we selected 14 species and we assayed the methanol extracts for antiproliferative activity against the HEp-2 (laryngeal cancer and NCI-H292 (lung cancer cell lines using the (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazole (MTT method. In addition, the antioxidant activity was evaluated with the DPPH (2,2-diphenyl-2-picrylhydrazyl assay, and the tannin content was determined by the radial diffusion method. Plants with better antioxidant activity (expressed in a dose able to decrease the initial DPPH concentration by 50%, or IC50 and with higher levels of tannins were: Poincianella pyramidalis (42.95 ± 1.77 µg/mL IC50 and 8.17 ± 0.64 tannin content, Jatropha mollissima (54.09 ± 4.36µg/mL IC50 and 2.35 ± 0.08 tannin content and Anadenanthera colubrina (73.24 ± 1.47 µg/mL IC50 and 4.41 ± 0.47 tannin content. Plants with enhanced antiproliferative activity (% living cells were Annona muricata (24.94 ± 0.74 in NCI-H292, Lantana camara (25.8 ± 0.19 in NCI-H292, Handroanthus impetiginosus (41.8 ± 0.47 in NCI-H292 and Mentzelia aspera (45.61 ± 1.94 in HEp-2. For species with better antioxidant and antiproliferative activities, we suggest future in vitro and in vivo comparative studies with other pharmacological models, and to start a process of purification and identification of the possible molecule(s responsible for the observed pharmacological activity. We believe that the flora of Brazilian semi-arid areas can be a valuable source of plants rich in tannins, cytotoxic compounds and antioxidant agents.

  2. Fungal weathering of asbestos in semi arid regions of India.

    Science.gov (United States)

    Bhattacharya, Shabori; John, P J; Ledwani, Lalita

    2016-02-01

    The science of Geomicrobiology, which deals with mineral- microbe interaction in nature contributes effectively to three important processes namely- mineral and metal bioremediation, biomining and soil mineral formation by microbes. Bioremediation one of the important process of the above, degrades or transforms hazardous contaminants to less toxic compounds. Several groups of fungi have proved highly efficient in this aspect, with asbestos being one such toxic entity in the environment on which their activity was studied. The present investigation uses the same tool as a device for detoxifying asbestos, a potent carcinogenic entity; with fungal isolates native to the asbestos mines of Rajasthan, India, being investigated for the first time. The cellular mechanism of asbestos toxicity is mainly attributed to the presence of iron in its chemical composition which catalyzes generation of free radicals leading to oxidation of biomolecules. The two dominant novel species found therein, identified as Aspergillus tubingenesis and Coemansia reversa have proved capable of actively removing iron from asbestos fibers as studied by scanning electron microscopy- electron diffraction X-ray (SEM-EDX) analysis. This probably could lead to a reduction in toxicity of asbestos, due to reduced iron concentration as reported in related studies. Many fungi are known to release iron chelating compounds, siderophores, which could be instrumental in the study. The findings related to two new fungal species being added to the list of earlier identified fungal bioremediators of asbestos, widens the prospect of using bioremediation as an effective tool for asbestos detoxification.

  3. The use of soil quality indicators to assess soil functionality in restored semi-arid ecosystems

    Science.gov (United States)

    Muñoz-Rojas, Miriam; Erickson, Todd E.; Dixon, Kingsley W.; Merritt, David J.

    2016-04-01

    Keywords: Pilbara, 1-day CO2 test, microbial activity, mine restoration, soil health, ecosystem services. Introduction Semi-arid and arid environments are highly vulnerable to land degradation and their restoration has commonly showed low rates of success (James et al., 2013). A systematic knowledge of soil functionality is critical to successful restoration of degraded ecosystems since approximately 80% of ecosystem services can be connected to soil functions. The assessment of soil functionality generally involves the evaluation of soil properties and processes as they relate to the ability of soil to function effectively as a component of a healthy ecosystem (Costantini et al., 2015) Using soil quality indicators may be a valuable approach to assess functionality of topsoil and novel substrates used in restoration (Muñoz-Rojas et al., 2014; 2015). A key soil chemical indicator is soil organic C, that has been widely used as an attribute of soil quality because of the many functions that it provides and supports (Willaarts et al., 2015). However, microbial indicators can be more sensitive to disturbances and could be a valuable addition in soil assessment studies in restoration programs. Here, we propose a set of soil quality indicators to assess the soil status in restored soils (topsoil and waste material) of semi-arid environments. The study was conducted during March 2015 in the Pilbara biogeographical region (northwestern Australia) at an iron ore mine site rehabilitated in 2011. Methods Soil samples were collected from two sub-areas with different soil materials used as growth media: topsoil retrieved from nearby stockpiles and a lateritic waste material utilised for its erosive stability and physical competence. An undisturbed natural shrub-grassland ecosystem dominated by Triodia spp. and Acacia spp. representative of the restored area was selected as the analogue reference site. Soil physicochemical analysis were undertaken according to standard methods

  4. Ethno-ornithology and conservation of wild birds in the semi-arid Caatinga of northeastern Brazil.

    Science.gov (United States)

    Alves, Rômulo Romeu Nóbrega; Leite, Railson Cidennys Lourenço; Souto, Wedson Medeiros Silva; Bezerra, Dandara M M; Loures-Ribeiro, Alan

    2013-01-01

    The utilization of birds as pets has been recognized as one of the principal threats to global avifauna. Most of the information about the use and sale of birds as pets has been limited to areas of high biodiversity and whose impacts of anthropic actions have been widely broadcast internationally, for example for the Amazon Forest and forest remnants of Southeast Asia. The Caatinga predominates in the semi-arid region of Brazil, and is one of the semi-arid biomes with the greatest biological diversity in the world, where 511 species of birds exist. Many of these birds are used as pets, a common practice in the region, which has important conservationist implications but has been little studied. Therefore, the aim of the present study was to detail aspects of the use of birds as pets in a locality in the semi-arid region of Northeast Brazil. Information on the use of avifauna was obtained through interviews and visits to the homes of 78 wild bird keepers. A total of 41 species of birds were recorded, mostly of the families Emberizidae (n = 9 species), Columbidae (n = 7 species), Icteridae (n = 6 species) and Psittacidae (n = 3 species). The birds that were most often recorded were Paroaria dominicana (n = 79 especimens), Sporophila albogularis (n = 67), Aratinga cactorum (n = 49), Sporophila lineola (n = 36), Sicalis flaveola (n = 29) and Sporophila nigricollis (n = 27). The use of wild birds in the area studied, as an example of what occurs in other places in the semi-arid Northeast, demonstrates that such activities persist in the region, in spite of being illegal, and have been happening in clandestine or semi-clandestine manner. No statistically significant correlation were found between socioeconomic factors and keeping birds as pets reflects the cultural importance of this practice of rearing wild birds for pets in the region, which is widespread among the local population, independent of socioeconomic factors. Obviously, human pressure on the avifauna

  5. Utilisation Of Micro-Finance Institutions’ Funds By Borrowers In Arid And Semi-Arid Lands In Kenya

    OpenAIRE

    Nzioki, Paul M.; Taragon, Geoffrey; Kalio, A. M.

    2013-01-01

    Despite a lot of efforts in terms of resource mobilisation in Arid and Semi-Arid Lands (ASAL) , the poverty levels are still very high and the defaulted loans from the four Micro-Finance Institutions (MFIs) in Maralal town amounts KES 15 million. The study sought to establish whether economic characteristics of entrepreneurs and whether literacy levels affect application and usage of borrowed funds in the ASAL regions of Africa. The study was limited to Maralal Town, one of the main towns in ...

  6. Aquatic systems in semi-arid Brazil: limnology and management Ecossistemas aquáticos do semi-árido brasileiro: aspectos limnológicos e manejo

    Directory of Open Access Journals (Sweden)

    José Etham de Lucena Barbosa

    2012-03-01

    Full Text Available Aquatic systems in semi-arid Brazil include natural shallow lakes, artificial reservoirs and intermittent streams and rivers. These systems are distinctive features in the semi-arid landscape and comprise a range of associated systems functioning as an ever-changing mosaic of dry/wet patches. Lakes and reservoirs in semi-arid Brazil are subject to important periods of water shortages, whereas rivers and streams are characterized as highly variable and driven by the extremes of water flow and its absence. Within this view a catchment-scale approach must be used to create a holistic model to conceptualize and comprehend these aquatic systems, since the aquatic environment types in the semi-arid region of Brazil incorporate broader aspects within the catchment scale such as geomorphology, vegetation, climate and land use. This paper summarizes some of the information on the aquatic systems of the Brazilian semi-arid region and shows the importance of limnological studies in this region. It also attempts to establish perspectives for future research considering the catchment as a scale for surveying biological processes and limnological characteristics of the various aquatic systems. It is presented information on their overall structure and functioning, as well as characteristics of some biological communities, such as phytoplankton, periphyton, aquatic macrophytes, benthic invertebrates and fish. The importance of the understanding of eutrophication in reservoirs and the role of the dry phase in streams is emphasized, and information on possible actions of planning and management to improve water quality of reservoirs are presented.Os ecossistemas no semiárido brasileiro englobam lagos rasos naturais, reservatórios artificiais e rios e riachos intermitentes. Estes sistemas são particularidades na paisagem do semiárida e compreendem uma grande variedade de sistemas associados, funcionando como um mosaico em constante mudança entre épocas de

  7. A groundwater development program for semi-arid northeast Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Maurice, Y. [Geological Survey of Canada, Ottawa, ON (Canada)

    2001-07-01

    A four-year technology transfer program, the Northeastern Brazil Groundwater Project, was initiated by the Geological Survey of Canada and the Geological Survey of Brazil (CPRM), in collaboration with several public and private institutions in both countries and was approved in April 2000. The program also benefits from support from the Canadian International Development Agency. The objective of the program is to develop the groundwater resources of northeast Brazil to provide the long-term stability socio-economic of the region. The area covers approximately one million square kilometres, touches three states and is frequently affected by droughts. The population hovers around the 25 million mark. The groundwater is brackish and contained in open bedrock fractures in the Precambrian basement and shallow alluvial aquifers. The difficulty associated with the predictability of the distribution forced many communities to store rain water in small reservoirs, increasing the risk of contamination and causing evaporation problems. A groundwater resource assessment program of the entire area was launched by CPRM in early 2000, which involved geological mapping, inventorying water wells, and measuring standard well and groundwater parameters, documenting water usage and supply and quality problems. The harder hit regions are the sites of more technologically advanced activities combined with considerable social work performed by Canadians and Brazilians alike. Seminars, short courses, in-field demonstrations of techniques and equipment, joint pilot-scale projects, technical visits and the training of Brazilians in Canada are the methods of choice for the transfer of technology and know-how by Canadians. Ground and airborne geophysics,remote sensing, hydrofrac, artificial aquifer recharge, groundwater modeling and geographic information system techniques are the technologies to be introduced. Great expectations are placed on the use of airborne electromagnetics (EM) for the

  8. Semi-Arid Water Resource Challenges - Can Water Harvesting Close the Gap?

    Science.gov (United States)

    Meixner, T.; Niraula, R.; Norman, L.; Pivo, G.; Gerlak, A.; Pavao-Zuckerman, M.; Henry, A.

    2015-12-01

    Water resource availability restricts development in arid and semi-arid regions of world. Past observations show that urban areas can increase stream discharge at least on a local scale. These results suggest that urbanization may increase the availability of wet water capable of being used by urban society. Here we present a combination of observational work demonstrating the increase of available water in urban areas of southern Arizona; and a modelling study demonstrating that future land use change may significantly increase river discharge across the Santa Cruz watershed which is ~12% urban. The observational data comes from over 30 watersheds varying in cover from undeveloped to highly urban and in spatial scale from a few square meters to thousands of square kilometers. The modelling study includes a conservation (~35% urban), megalopolitan (~34% urban) and business as usual scenario (~38% urban) for land use change due to regional population growth. All land use change scenarios result in significant increases in watershed streamflow. Depending upon pattern of urbanization, streamflow increased as much 88% in some watershed locations; demonstrating the potential to partially meet water resources demands in the region with water produced by the urbanization process. This water could be used regionally or locally, and significant efforts at implementing water harvesting in the region have been pursued. However, the ability to scale such implementation and overcome the physical, and social barriers to implementation are currently unquantified.

  9. Biogeochemical factors contributing to enhanced carbon storage following afforestation of a semi-arid shrubland

    Directory of Open Access Journals (Sweden)

    J. M. Grünzweig

    2007-07-01

    Full Text Available Ecosystems in dry regions are generally low in productivity and carbon (C storage. We report, however, large increases in C sequestration following afforestation of a semi-arid shrubland with Pinus halepensis trees. Using C and nitrogen (N inventories, based in part on site-specific allometric equations, we measured an increase in the standing ecosystem C stock from 2380 g C m−2 in the shrubland to 5840 g C m−2 in the forest after 35 years, with no significant change in N stocks. The total amount of C produced by the forest was estimated as 6250 g C m−2. Carbon sequestration following afforestation was associated with increased N use efficiency as reflected by an overall increase in C/N ratio from 7.6 in the shrubland to 16.6 in the forest. The C accumulation rate in the forest was particularly high for soil organic C (SOC; increase of 1760 g C m−2 or 50 g C m−2 yr−1, which was associated with the following factors: 1 Analysis of a small 13C signal within this pure C3 system combined with size fractionation of soil organic matter indicated a significant addition of new SOC derived from forest vegetation (68% of total forest SOC and a considerable portion of the old original shrubland SOC (53% still remaining in the forest. 2 A large part of both new and old SOC appeared to be protected from decomposition as about 60% of SOC under both land-use types were in mineral-associated fractions. 3 A short-term decomposition study indicated decreased decomposition of lower-quality litter and SOC in the forest, based on reduced decay rates of up to 90% for forest compared to shrubland litter. 4 Forest soil included a significant component of live and dead roots. Our results showed the considerable potential for C sequestration, particularly in soils, following afforestation in semi-arid regions, which is particularly relevant in light of persistent

  10. Management of nutrients and water in rainfed arid and semi-arid areas. Proceedings of a consultants meeting

    International Nuclear Information System (INIS)

    Sustainable food security is needed for the arid and semi-arid regions of the tropical, subtropical and warm-temperate climatic zones. In these regions the supply of locally grown food is unreliable because much of it is produced in conditions of highly variable rainfall. Even in favourable seasons, these regions re becoming increasingly dependent on imported food. The IAEA's involvement in field studies on soil-water use dates back several years. A five year Co-ordinated Research Project on ''The Use of Nuclear and Related Techniques in Assessment of Irrigation Schedules of Field Crops to Increase Effective Use of Water in Irrigation Projects''. That project, completed in 1995, laid a solid foundation for future research. Because of a scarcity of water in many developing countries and increasing needs for sustainable food security in the face of increasing populations and lack of funds for irrigation schemes of significant dimension, research must focus on improved management of (i) the modest quantities of fertilizers that are available to farmers, (ii) the natural resources that are available to farmers for increasing soil organic matter content, and (iii) rain water. The Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture held a Consultants Meeting on Management of Nutrients and Water in Rainfed Arid and Semi-Arid Areas for Increasing Crop Production, 26-29 May 1997

  11. Caracterização de solos em uma topoclimossequência no maciço de triunfo - sertão de pernambuco Soil characterization along a climatic gradient in the triunfo mountain range, semi-arid region of pernambuco state, Brazil

    Directory of Open Access Journals (Sweden)

    Rômulo Vinícius Cordeiro Conceição de Souza

    2010-08-01

    ável pela diferenciação dos solos ao longo da topoclimossequência, devendo-se ressaltar, também, a influência do material de origem e do relevo.Highland forests in mountains of Northeast Brazil are islands of humid Atlantic forest in the midst of the semi-arid region. The climatic conditions are rather atypical, improved by the occurrence of orographic rainfall, which can reach 1,200 mm per year. In the state of Pernambuco, most of the scientific studies in these humid highland forests are focused on botanical and zoological aspects only, with very little information about soils. Aiming to study the soils of the humid mountains in the semi-arid region and to evaluate the influence of the various soil-forming factors on formation and evolution, three soil profiles were characterized for morphological, physical, chemical, and mineralogical properties in the Triunfo mountain range, at different altitude levels. The soil profiles were located in the municipalities of Serra Talhada (P1, Santa Cruz da Baixa Verde (P2 and Triunfo (P3, along a moisture and altitude gradient (topo-climatic sequence. The soils were morphologically similar, due to the low development degree, mainly in the soil profiles P3 (Triunfo and P2 (Santa Cruz, classified, respectively, as Oxic Haplustept and Typic Haplustept. In the lower part of profile P1 (Serra Tallhada, a low clay content and greater textural gradient classified the soil as Typic Haplustult. The results showed that all studied soils were developed from syenitic rocks, with influence of sediments from the upper part of the relief. The development degree of the soil of Triunfo, with the highest rainfall levels, was higher than of the others. Climate, acting mainly by the variation in moisture, was however not the only soil forming factor responsible for soil differentiation along the sequence, but parent material and relief were important as well.

  12. Spatial variation of size distribution of Sarcopoterium spinosum in semi-arid rangelands

    Science.gov (United States)

    Pariente, Sarah

    2014-05-01

    Rangelands of semi-arid regions exhibit a three-phase mosaic spatial pattern comprising three representative patches: shrubs, trampling routes, and the remaining intershrubs area (hereafter: intershrubs). These patches differ in their soil properties, vegetation, and hydrological characteristics, and the differences are attributed to the differing intensities of animal hoof impacts and trampling: highest in the routes, sporadic in the intershrubs and minimal in the shrubs. A study conducted in the area described below revealed that soil moisture and organic matter contents, and topographic incline varied in the increasing order: routes distance from the routes, i.e., shrubs located near trampling routes are expected to be bigger than those far from them. The research was conducted in the Goral Hills, in the northern Negev region of Israel. This is a hilly, semi-arid area, 350-500 m above sea level, with mean annual rainfall of 300 mm that falls between October/December and May. Average daily temperatures range from 10° C in the winter to 25° C in the summer. The lithology is chalk and limestone of the Eocene era. The soil is shallow, generally not deeper than 20 or 40 cm in the open spaces between shrubs and beneath shrubs, respectively. The research area, like many other semi-arid areas of the Old World, has been grazed by flocks of sheep and goats since prehistoric times. The predominant shrub in the area is Sarcopoterium spinosum. To confirm the above hypothesis 10 representative hillslopes - five south-facing and five north-facing - were randomly selected within the research area. On each, a plot measuring 3 X 18 m running down the backslope was randomly selected and divided into squares of 1 m2. The shrubs - Sarcopoterium spinosum - and routes were mapped and, for each shrub, the height, maximal length, and width at the middle of the canopy were measured, in order to determine the area of the canopy and the volume of the shrub. The shrubs were divided into

  13. Atributos químicos de solos sob diferentes usos em perímetro irrigado no semiárido de Pernambuco Soil chemical properties under different uses in an irrigated area in the semi arid region of Pernambuco, Brazil

    Directory of Open Access Journals (Sweden)

    Rossini Mattos Corrêa

    2009-04-01

    salinização do solo, tornando suas utilizações agrícolas menos sustentáveis.Soils developed at semi-arid climate can present salt accumulation, which compromise the agricultural use, being increased by inadequate irrigation management. Based on the use, the degradation of these soils can occur at higher or smaller intensity. This study aimed to evaluate the effect of soil uses based on physical and chemical properties of an irrigated area in the semi-arid region of northeastern Brazil. The soil uses were annual crops (C, fruticulture (F, pasture (P, discarded lands (D, or native vegetation (V. Disturbed soil samples were collected from the 0-10, 10-30 and 30-60 cm layers for chemical analysis, and undisturbed samples from the first two layers for soil density analysis. The indicators pH and electrical conductivity of the saturation extract, soil pH, available phosphorus, total organic carbon, exchangeable cations, calcium, magnesium, potassium, and sodium, cation exchange capacity, sum of bases, base saturation percentage, percentage of exchangeable sodium, and carbon stocks were subjected to multivariate analysis by Principal Component Analysis, and clustering by the Tocher method. The soil chemical properties under production systems was different from V; the chemical quality of the production systems C and D, and that of C and P was similar. For the uses C, D, P, and F, the values of the soil properties (pH, pH and electrical conductivity of the saturation extract, exchangeable calcium and magnesium, sum of bases, base saturation and available phosphorus was higher than for V in the three analyzed layers. The highest total organic carbon content was observed under F and P. The electrical conductivity of the saturation extract was higher under C, D and P than under F and V, indicating the beginning of a soil salinization process, thus characterizing them as less sustainable land uses.

  14. Effectiveness of conservation agriculture practices on soil erosion processes in semi-arid areas of Zimbabwe

    Science.gov (United States)

    Chikwari, Emmanuel; Mhaka, Luke; Gwandu, Tariro; Chipangura, Tafadzwa; Misi Manyanga, Amos; Sabastian Matsenyengwa, Nyasha; Rabesiranana, Naivo; Mabit, Lionel

    2016-04-01

    - The application of fallout radionuclides (FRNs) in soil erosion and redistribution studies has gained popularity since the late 1980s. In Zimbabwe, soil erosion research was mostly based on conventional methods which included the use of erosion plots for quantitative measurements and erosion models for predicting soil losses. Only limited investigation to explore the possibility of using Caesium-137 (Cs-137) has been reported in the early 1990s for undisturbed and cultivated lands in Zimbabwe. In this study, the Cs-137 technique was applied to assess the impact of soil conservation practices on soil losses and to develop strategies and support effective policies that help farmers in Zimbabwe for sustainable land management. The study was carried out at the Makoholi research station 30 km north of the Masvingo region which is located 260 km south of Harare. The area is semi-arid and the study site comprises coarse loamy sands, gleyic lixisols. The conservation agriculture (CA) practices used within the area since 1988 include (i) direct seeding (DS) with mulch, (ii) CA basins with mulch, and (iii) 18 years direct seeding, left fallow for seven years and turned into conventional tillage since 2012 (DS/F/C). The Cs-137 reference inventory was established at 214 ± 16 Bq/m2. The mean inventories for DS, CA basins and DS/F/C were 195, 190 and 214 Bq/m2 respectively. Using the conversion Mass Balance Model 2 on the Cs-137 data obtained along transects for each of the practices, gross erosion rates were found to be 7.5, 7.3 and 2.6 t/ha/yr for direct seeding, CA basins and the DS/F/C while the net erosion rates were found to be 3.8, 4.6 and 0 t/ha/yr respectively. Sediment delivery ratios were 50%, 63% and 2% in the respective order. These preliminary results showed the effectiveness of DS over CA basins in erosion control. The efficiency of fallowing in controlling excessive soil loss was significant in the plot that started as DS for 18 years but left fallow for 7

  15. Aquaculture and mangrove ecosys of temproductivity in arid and semi-arid Balochistan coastal environments

    International Nuclear Information System (INIS)

    A survey of coastal shrimp-pond operations, and the structure and functioning of coastal mangrove forest ecosystems with particular reference to Ecuador, indicates that certain physical parameters may be good predictors of key biological processes. The most important factors are those associated with the regional water balance, tidal and surface water circulation patterns, and the physicochemical properties of the underlying soils. One important conclusion to emerge from the analyses is that at both regional and local levels, well-developed and productive mangrove forest areas often represent the least desirable sites for the construction and operation of commercial shrimp ponds. In certain regards semi-arid and arid coastal environments where mangroves are poorly developed, shrimp ponds that are constructed on barren mud flats and inland salt pans appear to have the potential to produce higher yields of shrimp with fewer management problems and at a relatively lower production cost. The data and research results from coast of Baluchistan and elsewhere are briefly summarized to suggest why productive mangrove ecosystems to not make the best areas in which to obtain maximum shrimp-pond yields. (author)

  16. Biogeochemical and ecological impacts of livestock grazing in semi-arid southeastern Utah, USA

    Science.gov (United States)

    Fernandez, D.P.; Neff, J.C.; Reynolds, R.L.

    2008-01-01

    Relatively few studies have examined the ecological and biogeochemical effects of livestock grazing in southeastern Utah. In this study, we evaluated how grazing has affected soil organic carbon and nitrogen to a depth of 50 cm in grasslands located in relict and actively-grazed sites in the Canyonlands physiographic section of the Colorado Plateau. We also evaluated differences in plant ground cover and the spatial distribution of soil resources. Results show that areas used by domestic livestock have 20% less plant cover and 100% less soil organic carbon and nitrogen compared to relict sites browsed by native ungulates. In actively grazed sites, domestic livestock grazing also appears to lead to clustered, rather than random, spatial distribution of soil resources. Magnetic susceptibility, a proxy for soil stability in this region, suggests that grazing increases soil erosion leading to an increase in the area of nutrient-depleted bare ground. Overall, these results, combined with previous studies in the region, suggest that livestock grazing affects both plant cover and soil fertility with potential long-term implications for the sustainability of grazing operations in this semi-arid landscape. ?? 2007 Elsevier Ltd. All rights reserved.

  17. On the value of combined event runoff and tracer analysis to improve understanding of catchment functioning in a data-scarce semi-arid area

    OpenAIRE

    M. Hrachowitz; Bohte, R.; Mul, M.L.; Bogaard, T.A.; Savenije, H. H. G.; S. Uhlenbrook

    2011-01-01

    Hydrological processes in small catchments are not quite understood yet, which is true in particular for catchments in data scarce, semi-arid regions. This is in contrast with the need for a better understanding of water fluxes and the interactions between surface- and groundwater in order to facilitate sustainable water resources management in such environments, where both floods and droughts can result in severe crop loss. In this study, event runoff coefficient analysis and limited tracer ...

  18. Mapping Ecological Processes and Ecosystem Services for Prioritizing Restoration Efforts in a Semi-arid Mediterranean River Basin

    Science.gov (United States)

    Trabucchi, Mattia; O'Farrell, Patrick J.; Notivol, Eduardo; Comín, Francisco A.

    2014-06-01

    Semi-arid Mediterranean regions are highly susceptible to desertification processes which can reduce the benefits that people obtain from healthy ecosystems and thus threaten human wellbeing. The European Union Biodiversity Strategy to 2020 recognizes the need to incorporate ecosystem services into land-use management, conservation, and restoration actions. The inclusion of ecosystem services into restoration actions and plans is an emerging area of research, and there are few documented approaches and guidelines on how to undertake such an exercise. This paper responds to this need, and we demonstrate an approach for identifying both key ecosystem services provisioning areas and the spatial relationship between ecological processes and services. A degraded semi-arid Mediterranean river basin in north east Spain was used as a case study area. We show that the quantification and mapping of services are the first step required for both optimizing and targeting of specific local areas for restoration. Additionally, we provide guidelines for restoration planning at a watershed scale; establishing priorities for improving the delivery of ecosystem services at this scale; and prioritizing the sub-watersheds for restoration based on their potential for delivering a combination of key ecosystem services for the entire basin.

  19. UNESCO's G-WADI Program - Developing and Delivering Tools for Improved Water Management in Semi-arid and Arid Lands

    Science.gov (United States)

    Woodard, G. C.; Imam, B.; Sorooshian, S.

    2007-12-01

    UNESCO's Water and Development Information for Arid Lands - A Global Network (G-WADI) aims to strengthen the capacity to manage the water resources of arid and semi-arid areas around the globe through a network of international and regional cooperation. Six centers, including SAHRA headquartered at the University of Arizona and CHRS at UC-Irvine, are cooperating to improve water resource management by sharing knowledge and tools. Specific objectives include: improved understanding of the special characteristics of hydrological systems and water management needs in arid areas, through shared data and experiences; capacity building of individuals and institutions; raising awareness of advanced technologies for data provision, data assimilation, and system analysis; and promoting integrated basin management and the use of appropriate decision support tools. SAHRA coordinates G-WADI's information dissemination via G-WADI's web site and publications. Web-based resources include Global Water News Watch and the subscription service, Water News Tracker, plus access to remotely sensed precipitation data from HyDIS. Information on use of isotopes and chemical tracers is also featured. Materials and outcomes from various workshops and short courses on modeling, water harvesting, and impacts of climate change also are provided. While the intent is to benefit water resource managers in semi- arid and arid developing countries, the collaboration among international water centers, and perspectives and traditional knowledge gained from users, has benefitted U.S. researchers in many ways.

  20. Land degradation assessment by geo-spatially modeling different soil erodibility equations in a semi-arid catchment.

    Science.gov (United States)

    Saygın, Selen Deviren; Basaran, Mustafa; Ozcan, Ali Ugur; Dolarslan, Melda; Timur, Ozgur Burhan; Yilman, F Ebru; Erpul, Gunay

    2011-09-01

    Land degradation by soil erosion is one of the most serious problems and environmental issues in many ecosystems of arid and semi-arid regions. Especially, the disturbed areas have greater soil detachability and transportability capacity. Evaluation of land degradation in terms of soil erodibility, by using geostatistical modeling, is vital to protect and reclaim susceptible areas. Soil erodibility, described as the ability of soils to resist erosion, can be measured either directly under natural or simulated rainfall conditions, or indirectly estimated by empirical regression models. This study compares three empirical equations used to determine the soil erodibility factor of revised universal soil loss equation prediction technology based on their geospatial performances in the semi-arid catchment of the Saraykoy II Irrigation Dam located in Cankiri, Turkey. A total of 311 geo-referenced soil samples were collected with irregular intervals from the top soil layer (0-10 cm). Geostatistical analysis was performed with the point values of each equation to determine its spatial pattern. Results showed that equations that used soil organic matter in combination with the soil particle size better agreed with the variations in land use and topography of the catchment than the one using only the particle size distribution. It is recommended that the equations which dynamically integrate soil intrinsic properties with land use, topography, and its influences on the local microclimates, could be successfully used to geospatially determine sites highly susceptible to water erosion, and therefore, to select the agricultural and bio-engineering control measures needed.

  1. Diurnal and Seasonal Variation of Surface Urban Cool and Heat Islands in the Semi-Arid City of Erbil, Iraq

    Directory of Open Access Journals (Sweden)

    Azad Rasul

    2016-09-01

    Full Text Available The influence of land surface temperature (LST makes the near-surface layer of the troposphere a key driver of urban climate. This paper assesses the temporal formation of the daytime Surface Urban Cool Island (SUCI and night-time Surface Urban Heat Island (SUHI effect in Erbil, Iraq, situated in a semi-arid climate region. LST retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS Aqua and Terra and MODIS Normalized Difference Vegetation Index (NDVI from January 2003 to December 2014 are analysed. The relationships of LST with NDVI and the Normalized Multi-band Drought Index (NMDI are investigated in order to assess the influence of vegetation and moisture on the observed patterns of LST and the SUCI/SUHI. The results indicate that during the daytime, in summer, autumn and winter, densely built-up areas had lower LST acting as a SUCI compared to the non-urbanised area around the city. In contrast, at night-time, Erbil experienced higher LST and demonstrated a significant SUHI effect. The relationship between LST and NDVI is affected by seasonality and is strongly inverted during spring (r2 = 0.73; p < 0.01. Contrary to previous studies of semi-arid cities, a SUCI was detected, not only in the morning, but also during the afternoon.

  2. Mapping ecological processes and ecosystem services for prioritizing restoration efforts in a semi-arid Mediterranean river basin.

    Science.gov (United States)

    Trabucchi, Mattia; O'Farrell, Patrick J; Notivol, Eduardo; Comín, Francisco A

    2014-06-01

    Semi-arid Mediterranean regions are highly susceptible to desertification processes which can reduce the benefits that people obtain from healthy ecosystems and thus threaten human wellbeing. The European Union Biodiversity Strategy to 2020 recognizes the need to incorporate ecosystem services into land-use management, conservation, and restoration actions. The inclusion of ecosystem services into restoration actions and plans is an emerging area of research, and there are few documented approaches and guidelines on how to undertake such an exercise. This paper responds to this need, and we demonstrate an approach for identifying both key ecosystem services provisioning areas and the spatial relationship between ecological processes and services. A degraded semi-arid Mediterranean river basin in north east Spain was used as a case study area. We show that the quantification and mapping of services are the first step required for both optimizing and targeting of specific local areas for restoration. Additionally, we provide guidelines for restoration planning at a watershed scale; establishing priorities for improving the delivery of ecosystem services at this scale; and prioritizing the sub-watersheds for restoration based on their potential for delivering a combination of key ecosystem services for the entire basin.

  3. Interaction of water components in the semi-arid Huasco and Limarí river basins, North Central Chile

    Directory of Open Access Journals (Sweden)

    G. Strauch

    2009-10-01

    Full Text Available For sustainable water resource management in semi-arid regions, sound information is required about interactions between the different components of the water system: rain/snow precipitation, surface/subsurface run-off, groundwater recharge. Exemplarily, the Huasco and Limarí river basins as water stressed river catchments have been studied by isotope and hydrochemical methods for (i the origin of water, (ii water quality, (iii relations of surface and groundwater.

    Applying the complex multi-isotopic and hydrochemical methodology to the water components of the Huasco and Limarí basins, a differentiation of water components concerning subsurface flow and river water along the catchment area and by anthropogenic impacts are detected. Sulphate and nitrate concentrations indicate remarkable input from mining and agricultural activities along the river catchment.

    The 2H-18O relations of river water and groundwater of both catchments point to the behaviour of river waters originated in an arid to semi-arid environment.

    Consequently, the groundwater from several production wells in the lower parts of the catchments is related to the rivers where the wells located, however, it can be distinguished from the river water. Using the hydrological water balance and the isotope mixing model, the interaction between surface and subsurface flows and river flow is estimated.

  4. Fixation kinetics of chelated and non-chelated zinc in semi-arid alkaline soils: application to zinc management

    Science.gov (United States)

    Udeigwe, Theophilus K.; Eichmann, Madeleine; Menkiti, Matthew C.

    2016-07-01

    This study was designed to examine the fixation pattern and kinetics of zinc (Zn) in chelated (ethylenediaminetetraacetic acid, EDTA) and non-chelated mixed micronutrient systems of semi-arid alkaline soils from the Southern High Plains, USA. Soils were characterized for a suite of chemical and physical properties and data obtained from extraction experiments fitted to various kinetic models. About 30 % more plant-available Zn was fixed in the non-chelated system within the first 14 days with only about 18 % difference observed between the two systems by day 90, suggesting that the effectiveness of the chelated compounds tended to decrease over time. The strengths of the relationships of change in available Zn with respect to other micronutrients (copper, iron, and manganese) were higher and more significant in the non-chelated system (average R2 of 0.83), compared to the chelated (average R2 of 0.42). Fixation of plant-available Zn was best described by the power-function model (R2 = 0.94, SE = 0.076) in the non-chelated system, and was poorly described by all the models examined in the chelated system. Reaction rate constants and relationships generated from this study can serve as important tools for micronutrient management and for future micronutrient modeling studies on these soils and other semi-arid regions of the world.

  5. Short Communication: Rhizosphere bacteria containing ACC-deaminase conferred drought tolerance in wheat grown under semi-arid climate

    Directory of Open Access Journals (Sweden)

    Masood Ahmad Shakir

    2012-05-01

    Full Text Available Certain rhizobacteria have the potential of lowering endogenous ethylene levels in plants because of their 1- aminocyclopropane-1-carboxylate (ACC-deaminase activity and promoting root growth. This mechanism is of great agronomic significance under stress environments, which are known to induce accelerated production of ethylene. Thirty rhizobacteria were isolated from rhizosphere of wheat (Triticum aestivum L. growing in the Southern Punjab, a semi-arid region of Pakistan. Rhizobacteria were screened for ACC-deaminase activity and their potential to confer drought tolerance in wheat crop. Results of laboratory study revealed that selected rhizobacteria lowered endogenous ethylene levels in the rhizosphere as measured by Gas Chromatograph. Axenic studies showed that inoculation increased root-shoot length, root-shoot mass and lateral root number of the inoculated plants by 141, 44, 196, 52 and 30%, respectively, over control. Better-developed roots because of inoculation with plant growth promoting rhizobacteria (PGPR helped plants, a better crop stand that enhanced moisture and nutrient feeding volume resulting-in improved growth and yields of wheat crop. Two-year multi-location field trials inferred optimum yields with low delta water in semi-arid climate by PGPR containing ACC-deaminase. The enzyme ACC-deaminase probably lowered harmful ethylene levels which partially eliminated drought stress consequently utilizing soil moisture from lower profiles through proliferated roots.

  6. Desenvolvimento local ou migração? uma reflexão sobre as alternativas para os jovens do semiárido brasileiro. A reflection on the alternatives for young people in semi-arid regions of Brazil. Local development or Migration?

    Directory of Open Access Journals (Sweden)

    José Geraldo Wizniewsky

    2013-06-01

    Full Text Available Este trabalho tem como objetivo principal discutir a realidade da migração da mão de obra jovem, de uma comunidade localizada no semi-árido brasileiro. Como metodologia para este trabalho utilizou-se: uma pesquisa bibliográfica em artigos científicos e pesquisa documental em materiais técnicos disponibilizados por órgãos públicos, para coletar dados primários utilizou-se a observação direta e a discussão em grupo focal com 12 jovens, realizada em janeiro de 2010 numa cidade do interior do estado da Paraíba no nordeste Brasileiro. Entre os resultados, pode se observar que o fenômeno das migrações traz conseqüências para as regiões de saída e chegada. Desta forma é importante observar o que este fenômeno significa para o desenvolvimento do local, se existem implicações para o futuro da região o fato da mão de obra jovem estar sendo utilizada em outra região. Ao que parece o dinheiro que retorna ou que é enviado pelos migrantes amenizam a situação durante um curto espaço de tempo, mas a perda de jovens resulta em um prejuízo muito maior para a cidade a médio e longo prazo, favorecendo a manutenção de estruturas arcaicas que tanto prejudicam a região.The main objective of this essay is to discuss the reality of migration of young workforce from a community located in the semi-arid regions of Brazil. The methodology used for this essay was: a literature review in scientific articles and a documentary research on technical materials, made available by public organizations. In order to collect primary data, it was used direct observation and a discussion with a focused group of 12 young people, held in January 2010 in a city in the state of Paraiba, in northeastern Brazil. Among the results, it was noticed that the phenomenon of migration has consequences for the regions of departure and arrival, showing a complex reality with alarming rates of depletion of some small cities at certain times of the year. Another

  7. 基于生态足迹的半干旱草原区生态承载力与可持续发展研究——以内蒙古锡林郭勒盟为例%Ecological footprint analysis of a semi-arid grassland region facilitates assessment of its ecological carrying capacity: a case study of Xilinguole League

    Institute of Scientific and Technical Information of China (English)

    杨艳; 牛建明; 张庆; 张艳楠

    2011-01-01

    The development and testing of regional sustainable development indicators is an active research area. This study uses quantitative indicators to determine whether nature's ecological carrying capacity can satisfy the needs of humans. There are many quantitative measuring methods for sustainable development, but the ecological footprint analysis has a more widespread application. This method is used to calculate ecological footprints by looking at need and the ecological carrying capacity in terms of support, and study the use degree of humanity to natural. Using these results, the circumstances of an area or country's sustainable development may be .established.Xilinguole League is located 111°59'-120°00'E and 42°32'-6°41'N. The total area is 201442 km2, with agrassland area of 192000 km2, and covers one-quarter grassland area of the Inner Mongolia Autonomous Region.In this study we conducted an ecological footprint analysis of the Xilinguole League, using statistical data from 1981 to 2008. The computed ecological carrying capacity and its 30-year dynamics revealed the major development trends of this semi-arid grassland region. Our findings showed the following. (1) Rapid industrialization and urbanization altered the area's per capita ecological footprint dramatically. The area increased from 1.0868 hm2 in 1981 to 24.2176 hm2 in 2008, surpassing China's national average and that of other domestic grassland areas. The main driver of this increase was the rapid expansion of areas involved in the extraction of fossil fuels and other grassland uses. (2) Rapid population growth resulted in the decline of per capita ecological carrying capacity for this region, with grassland-cropland capacities being most affected. The total per capita ecological carrying capacity decreased from 3.1565 hm2 in 1981 to 2.3915 hm2 in 2008. (3) Development has been accompanied by a shift from a regional ecological surplus to an ecological deficit.Two factors are responsible for

  8. Analysis of Climate Characteristics of Land Surface Temperature and Energy in the Semi-arid Region in the Loess Plateau%黄土高原半干旱区陆面温度和能量的气候特征分析

    Institute of Scientific and Technical Information of China (English)

    孙昭萱; 张强

    2011-01-01

    利用黄土高原半干旱区"定西陆面过程综合观测试验站"2004年11月至2005年10月的各种陆面物理量综合资料,比较系统地研究了黄土高原半干旱区土壤温度、降水量、地表反照率、地表辐射分量和能量平衡分量的年变化和日变化特征及其影响机制。结果显示,黄土高原陆面过程特征与其他地区有很大不同。土壤温度变化向下传播速度约为2.5~3.5 h/10cm;地表反照率随土壤湿度的增大而减小,两者的相关系数达到了0.5338;而地表反照率随降雪量增大而增大,与降雪量的相关系数为0.6645;长波辐射年最大值出现的时间比总辐射迟1个月左右,年平均日变化中地表和大气对太阳辐射加热大约需要1个小时的响应时间;潜热通量夏季是冬季的5倍多,感热通量有了两个比较明显的峰值,潜热通量、感热通量和土壤热通量的日峰值比净辐射滞后30 min~1 h。%By making use of integrated data of a variety of land surface physical parameters observed in Dingxi Synthetical Experimental Observatory of Land Surface Process in the Loess Plateau from November,2004 to October,2005,annual and daily variations characteristics of soil temperature,precipitation,land surface albedo,surface radiation components and energy balance components in the semi-arid region are systematically analyzed,as well as their influencing mechanism.Results show that the characteristics of land surface process over the Loess Plateau are different from in other regions.Downward transfer velocity of soil temperature is about 2.5~3.5 h/10cm.The land surface albedo decreases with soil moisture increasing,and their correlation coefficient is 0.5338;the land surface albedo increases with snowfall increasing,and the correlation coefficient is 0.6645.The maximum value of long-wave radiation appears later about 1 month than the total radiation.It takes one hour for solar radiation to heat the land surface and atmosphere

  9. Impacts of climate change on nutrient cycling in semi-arid and arid ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Belnap, J. [National Biological Survey, Moab, UT (United States)

    1995-09-01

    Effective precipitation is a major factor in determining nutrient pathways in different ecosystems. Soil flora and fauna play a critical role in nutrient cycles of all ecosystems. Temperature, timing, and amounts of precipitation affect population composition, activity levels, biomass, and recovery rates from disturbance. Changes in these variables can result in very different inputs and outputs for different nutrients. As a result, areas with less effective precipitation have very different nutrient cycles than more mesic zones. Climate change, therefore, can profoundly affect the nutrient cycles of ecosystems. Nitrogen cycles may be especially sensitive to changes in temperature and to timing and amounts of precipitation. Rainfall contains varying amounts of nitrogen compounds. Changes in amounts of rainfall will change amounts of nitrogen available to these systems. Because rainfall is limited in semi-arid and regions, these systems tend to be more dependent on microbial populations for nitrogen input. Consequently, understanding the effects of climate change on these organisms is critical in understanding the overall effect on ecosystems.

  10. Effects of stubble and mulching on soil erosion by wind in semi-arid China

    Science.gov (United States)

    Cong, Peifei; Yin, Guanghua; Gu, Jian

    2016-07-01

    Soil erosion is a growing challenge for agricultural production in Northern China. To explore the effect of variation in stubble height and mulching biomass on soil erosion caused by wind, we conducted a field experiment using a quadratic rotation combination design. Results showed that the quantity of straw mulch was the dominant factor affecting soil erosion, and stubble height was of secondary importance. The soil water content in stubble and straw mulching treatments was higher than in a control treatment at 0-20 cm soil, and the tendency in the amount of soil water content was opposite to the amount of wind erosion (r = -0.882, n = 10, p soil water content observed in the stubble and mulch treatments at the 15-20 cm depth was higher than the change from 0-5 cm to 5-10 cm. Combined, the influence of a stubble height of 34 cm and mulch quantity of 4260 kg·ha-1 lowered the amount of erosion to 0.42 t·ha-1, and increased the corn yield to 11900 kg·ha-1. We determined that those were the most appropriate levels of stubble height and straw mulch for crop fields in the semi-arid regions of Northern China.

  11. Coupled flow and salinity transport modelling in semi-arid environments: The Shashe River Valley, Botswana

    Science.gov (United States)

    Bauer, Peter; Held, Rudolf J.; Zimmermann, Stephanie; Linn, Flenner; Kinzelbach, Wolfgang

    2006-01-01

    Numerical groundwater modelling is used as the base for sound aquifer system analysis and water resources assessment. In many cases, particularly in semi-arid and arid regions, groundwater flow is intricately linked to salinity transport. A case in point is the Shashe River Valley in Botswana. A freshwater aquifer located around an ephemeral stream is depleted by the combined effect of transpiration and pumping. Quantitative system analysis reveals that the amount of water taken by transpiration is far more than the quantities pumped for water supply. Furthermore, the salinity distribution in and around Shashe River Valley as well as its temporal dynamics can be satisfactorily reproduced if the transpiration is modelled as a function of groundwater salinity. The location and dynamics of the saltwater-freshwater interface are highly sensitive to the parameterization of evaporative and transpirative salt enrichment. An existing numerical code for coupled flow/transport simulations (SEAWAT) was adapted to this situation. Model results were checked against a large set of field data including water levels, water chemistry, isotope data and ground and airborne geophysical data. The resulting groundwater model was able to reproduce the long-term development of the freshwater lens located in Shashe River Valley as well as the decline in piezometric heads observed over the last decade. Furthermore, the old age of the saline water surrounding the central freshwater lens could be explained.

  12. Characterising root density of peach trees in a semi-arid Chernozem to increase plant density

    Science.gov (United States)

    Paltineanu, Cristian; Septar, Leinar; Gavat, Corina; Chitu, Emil; Oprita, Alexandru; Moale, Cristina; Calciu, Irina; Vizitiu, Olga; Lamureanu, Gheorghe

    2016-01-01

    The available information on root system in fully mature peach orchards in semi-arid regions is insufficient. This paper presents a study on the root system density in an irrigated peach orchard from Dobrogea, Romania, using the trench technique. The old orchard has clean cultivation in inter-row and in-row. The objectives of the study were to: test the hypothesis that the roots of fully mature peach trees occupy the whole soil volume; find out if root repulsive effect of adjacent plants occurred for the rootstocks and soil conditions; find relationships between root system and soil properties and analyse soil state trend. Some soil physical properties were significantly deteriorated in inter-row versus in-row, mainly due to soil compaction induced by technological traffic. Density of total roots was higher in-row than inter-row, but the differences were not significant. Root density decreased more intensely with soil depth than with distance from tree trunks. Root density correlated with some soil properties. No repulsive effect of the roots of adjacent peach trees was noted. The decrease of root density with distance from trunk can be used in optimising tree arrangement. The conclusions could also be used in countries with similar growth conditions.

  13. The management of nutrients and water in the west African semi-arid tropics

    International Nuclear Information System (INIS)

    At present, the farming systems in the west African semi-arid tropics are unsustainable, low in productivity, and destructive to the environment. A striking feature of the soils is their inherently low fertility, with negative plant-nutrient balance in many cropping systems. Research in N-use efficiency (NUE) indicated that calcium ammonium nitrate (CAN) significantly outperformed urea on millet. Fertilizer losses, greater for urea (53%) than for CAN (25%) were believed to be due to ammonia volatilization. Continuous cropping resulted in lower yields compared to a cereal grown after cowpea or groundnut, and NUE was improved with crop rotation. Phosphorus deficiency is a major constraint. Phosphate rock (PR), indigenous to the region, e.g. at Tahoua in Niger and Tilemsi in Mali, is suitable for direct application. Partial acidulation of low-solubility PR improves agronomic effectiveness. Long-term soil-fertility management trials indicate that although application of mineral fertilizers increase yields, they alone cannot sustain productivity. When mineral fertilizers are combined with other technologies, such as the return of crop residues and manure, productive and sustainable production systems are possible. Water-use efficiency increased dramatically with the addition of plant nutrients. Technologies for land surface management and water harvesting, and appropriate cropping systems with careful varietal selection all contribute to the optimization of soil-water use. Future research should focus on water and nutrient interactions and on understanding why presently available improved technologies are not adopted by farmers even when using a participatory approach. (author)

  14. Adaptation to drought in arid and semi-arid environments: Case of the Zambezi Valley, Zimbabwe

    Directory of Open Access Journals (Sweden)

    Emmanuel Mavhura

    2015-02-01

    Full Text Available Small-scale rain-fed agriculture is the main livelihood in arid to semi-arid regions of subSaharan Africa. The area is characterised by erratic rainfall and frequent droughts, making the capacity for coping with temporal water shortages essential for smallholder farmers. Focusing on the Zambezi Valley, Zimbabwe, this study investigates the impact of drought on food security and the strategies used by smallholder farmers to cope with drought. We used meteorological data and interviews to examine the rainfall variability in the study area and the drought-coping mechanisms employed by smallholder famers respectively. The results show that there are various strategies used by smallholder farmers to cope with the impact of drought. These strategies include drought-tolerant crop production, crop variety diversification, purchasing cereals through asset sales, non-governmental organisations’ food aid and gathering wild fruit. However, consecutive droughts have resulted in high food insecurity and depletion of household assets during droughts. Smallholder farmers in the valley have also resorted to a number of measures taken before, during and after the drought. Still, these strategies are not robust enough to cope with this uncertainty

  15. Can groundwater in the discharge area receive recharge from rainfall in semi-arid areas?

    Science.gov (United States)

    Jiang, Xiao-Wei; Sun, Zhi-Chao; Zhao, Ke-Yu; Wan, Li; Wang, Xu-Sheng

    2016-04-01

    The definition of discharge area, which could be traced back to Toth (1962), is an area where the flow of groundwater is directed upward with respect to the water table. However, such a definition is subjected to criticism because it is usually accepted that rainfall can infiltrate into the subsurface and recharge the aquifer. In this study, the water table and soil moisture in the discharge area of an inland watershed in northwestern China with a semi-arid climate are monitored. The water table is recorded using Diver, while soil moistures at ten different depths are recorded using 5TM. The hourly rainfall data is also available in a nearby weather station. Both groundwater and soil water are found to have responses to heavy rainfalls. Soil moisture in the shallow part (soil moisture is dependent on the amount of rainfall. Soil moisture in the deep part (>90 cm) also have response to heavy rainfalls, however, they have a more direct relation to the dynamics of the water table. Based on the variations in soil moisture, we conclude that the rise in water table is not caused by the in situ infiltration of rainfall, and the infiltrated rainfall got evaporated before arriving at the water table. The vertical flux from regional groundwater flow is found to be the main contribution of water supply to support evaporation.

  16. Great Basin semi-arid woodland dynamics during the late quaternary

    Energy Technology Data Exchange (ETDEWEB)

    Wigand, P.E.; Hemphill, M.L.; Sharpe, S.E. [Univ. and Community College System of Nevada, Reno, NV (United States)] [and others

    1995-09-01

    Semi-arid woodlands have dominated the middle elevations of Great Basin mountain ranges during the Holocene where subalpine woodlands prevailed during the Pleistocene. Ancient woodrat middens, and in a few cases pollen records indicate in the late Pleistocene and early Holocene woodland history lowered elevation of subalpine woodland species. After a middle Holocene retrenchment at elevations in excess of 500 meters above today, Juniper-dominated semi-arid woodland reached its late Holocene maximum areal extent during the Neoglacial (2 to 4 ka). These records, along with others indicate contracting semi-arid woodland after the Neoglacial about 1.9 ka. Desert shrub community expansion coupled with increased precariousness of wetland areas in the southern Great Basin between 1.9 and 1.5 ka coincide with shrinking wet-lands in the west-central and northern Great Basin. Coincident greater grass abundance in northern Great Basin sagebrush steppe, reaching its maximum between 1.5 and 1.2 ka, corresponds to dramatic increases in bison remains in the archaeological sites of the northern Intermontane West. Pollen and woodrat midden records indicate that this drought ended about 1.5 ka. Succeeding ameliorating conditions resulted in the sudden northward and downward expansion of pinon into areas that had been dominated by juniper during the Neoglacial. Maximum areal extent of pinon dominated semi-arid woodland in west-central Nevada was centered at 1.2 ka. This followed by 100 years the shift in dominance from juniper to pinon in southern Nevada semi-arid woodlands. Great Basin woodlands suffered from renewed severe droughts between .5 to .6 ka. Effectively wetter conditions during the {open_quotes}Little Ice Age{close_quotes} resulted in re-expansion of semi-arid woodland. Activities related to European settlement in the Great Basin have modified prehistoric factors or imposed new ones that are affecting woodland response to climate.

  17. WATER AND SEDIMENT TOXICITY ASSESSMENT OF THE JABURU RESERVOIR (CEARÁ-BR IN THE SEMI-ARID REGION = AVALIAÇÃO DA TOXIDADE DA ÁGUA E SEDIMENTO DO AÇUDE JABURU (CEARÁ-BR NA REGIÃO DO SEMI-ÁRIDO

    Directory of Open Access Journals (Sweden)

    Milena Viana de Sousa

    2012-01-01

    Full Text Available The reservoirs are the only resource available to people supply in semi-arid region during the dry season. However, these reservoirs are also used for crop irrigation, which is done on the vicinity of the reservoir. Due to the continuous use of fertilizers and pesticides, these products are carried to the water polluting them. The Jaburu reservoir, located in northwestern of Ceará’ State, is used for supplying eight cities and eight villages and districts. Acute toxicity tests were done in this reservoir on water and sediment, using the organisms Daphnia magna, algae Pseudokirchneriella subcapitata and lettuce seeds, and also chronic toxicity test in the water with Daphnia magna. It was assessed three points in three different depths to determine the stratification effect, during the dry and rainy seasons. Acute toxicity was not detected in the water in the all sampled points. In the chronic test, toxicity was detected in both periods, dry and rainy, and it was more severe during the dry season. In the sediment, there was acute toxicity in water during the dry season for only D. magna, while for the other organisms no toxicity was detected. Results showed that the Jaburu reservoir was not severely impacted yet, but the chronic tests showed contamination of water by pollutants in low concentrations, causing long-term effect. Appropriate regulatory management should be done to prevent future impact on this ecosystem. = Os açudes são o único recurso disponível para abastecimento de água da população na região semi-árida durante a estação seca. Esse recurso, porém, também é utilizado na agricultura desenvolvida no entorno do açude, para irrigação. Devido ao uso contínuo de fertilizantes e pesticidas, esses produtos podem ser carreados para as águas, poluindo-as. O Açude Jaburu, localizado na região noroeste do Estado do Ceará, é responsável pelo abastecimento de oito cidades e oito vilas e distritos. Nele, foram realizados

  18. Análise espaço-temporal do uso da terra em parte do semi-árido cearense Spatial and temporal-time analysis of land use in part of the semi-arid region of Ceará State, Brazil

    Directory of Open Access Journals (Sweden)

    J. B. Andrade

    2004-04-01

    Full Text Available A cobertura vegetal exerce papel imprescindível à proteção e conservação dos recursos naturais, principalmente no que diz respeito aos solos. Este estudo teve como objetivo avaliar e analisar a dimensão espacial e temporal da ação antrópica na cobertura vegetal de parte do semi-árido cearense, utilizando imagens LANDSAT TM-5, de 1985 e 1994, e técnicas de geoprocessamento, para verificar a hipótese de que a degradação ambiental vem sendo intensificada. Foram confeccionadas cartas de vegetação, uso da terra, solos e hidrografia, obtendo-se cartas de sobreposição, por meio das quais se constatou o aumento de áreas degradadas nas diferentes unidades fitoecológicas. No período de uma década, comprovou-se o processo progressivo da degradação nas áreas dos municípios de Independência, Pedra Branca, Mombaça e Tauá, tendo as áreas do município de Pedra Branca apresentado menor degradação. A unidade fitoecológica mais degradada, dentre as estudadas, foi a Caatinga Arbórea Aberta, desencadeando processos de degradação e transformação das unidades circunvizinhas. Grande parte da área foi atingida por processos de degradação ambiental, com forte pauperização da biodiversidade, acompanhados por um rebaixamento geral das formações vegetais.The vegetation cover plays a key role in protection and conservation of natural resources, particularly concerning soils. This study had as objective to analyze space and time dimensions of anthropic influence on the vegetation cover in part of the semi-arid region of the Ceará State, Brazil. LANDSAT TM-5 satellite images of 1985 and 1994 combined with geoprocessing techniques were used to verify the hypothesis of intensification of environmental degradation. Maps of the vegetation cover, land use, soils, and hydrography were elaborated. They pointed out to an increase in degraded areas of the different phytoecological units. During this decade, a progressive degradation

  19. Perfil microbiológico, celular e fatores de risco associados à mastite subclínica em cabras no semiárido da Paraíba Cellular and microbiological profiles and risk factors for subclinical mastitis in goats in the semi-arid region of Paraíba

    Directory of Open Access Journals (Sweden)

    Patrícia B. Neves

    2010-05-01

    Full Text Available Foi realizado um estudo da mastite subclínica em nove rebanhos de cabras leiteiras no semiárido paraibano com o objetivo de determinar a ocorrência da infecção, avaliar o perfil microbiológico e celular do leite, testar a sensibilidade dos microorganismos isolados frente a antimicrobianos além de identificar os fatores de risco. Foram utilizadas 131 cabras leiteiras das quais foram colhidas 261 amostras de leite para exame microbiológico e 131 para contagem de células somáticas (CCS. Na ocasião das colheitas foi realizado o California Mastitis Test (CMT e aplicado um questionário epidemiológico por propriedade. Houve crescimento bacteriano em 30 amostras (11,49% com 25 (83,33% dos isolados identificados como Staphylococcus coagulase negativa e cinco (16,66% Staphylococcus aureus. A média de CCS foi de 1,39x10(6 células/ml. O CMT apresentou baixa sensibilidade (46,7% e baixa especificidade (60,6% quando comparado ao exame microbiológico. A gentamicina e a associação da neomicina, bacitracina e tetraciclina foram os antimicrobianos contra os quais os microrganismos isolados apresentaram 100% de sensibilidade. Penicilina e ampicilina foram os de maiores índices de resistência (66,67% e 63,89%, respectivamente. A caprinocultura não ser a atividade principal da propriedade e o não isolamento de animais doentes, foram identificados como fatores de risco para a mastite subclínica caprina nas propriedades estudadas. Programas de controle e profilaxia da mastite devem ser implementados enfocando as medidas de higiene na ordenha e correção dos fatores de risco identificados nesse estudo.A subclinical mastitis study was conducted in nine dairy goat herds in the semi-arid region of Paraíba state, Northeastern Brazil, to determine the occurrence of infection, to evaluate microbiological and cellular profiles of the milk, to test the sensitivity of isolated microorganisms to antimicrobials, and to identify risk factors. One hundred

  20. Simulation of spectral bands of the MERIS sensor to estimate chlorophyll-a concentrations in a reservoir of the semi-arid region = Simulação de bandas espectrais do sensor MERIS para estimativas das concentrações de clorofila-a em reservatório da região semiárida

    Directory of Open Access Journals (Sweden)

    Fernando Bezerra Lopes

    2016-07-01

    Full Text Available Nowadays, the monitoring of water is essential for the sustainability and better management of water resources. The use of remote sensing data is important, since it allows evaluation of dynamic problems in aquatic systems, such as the eutrophication of bodies of water and suspended sediment. The aim of this study was to estimate chlorophyll-a concentrations in a reservoir of the semi-arid region of Brazil using simulated orbital-sensor data, as an aid in the management of water resources. The study area corresponded to the Orós reservoir, in the State of Ceará, Brazil. Water samples for analysis of the chlorophyll-a and measurements of the spectral radiance of the aquatic system were collected from 20 points. The radiance was measured by spectroradiometer. The data were collected in June and August of 2011. The model using three bands of the MERIS sensor (7, 9 and 10 presented an R2 of 0.84. For the two-band model (7 and 9, the value of R2 was 0.85. The waters of the Orós reservoir were all classified as eutrophic. The main optically active component in modelling the shape of the spectra was chlorophyll-a. The models showed a mean absolute error (MAE of 3.45 and 3.61 μg L-1 for the three- and two-band models respectively. The models displayed high coefficients of determination, i.e. the simulations show the feasibility of estimating chlorophyll-a concentration from the data of the MERIS orbital sensor. = O monitoramento da água nos dias atuais é essencial para a sustentabilidade e para a melhor gestão dos recursos hídricos. O uso de dados de sensoriamento remoto é relevante, uma vez que permite a avaliação de problemas dinâmicos em sistemas aquáticos, tais como a eutrofização de corpos de água e dos sedimentos em suspensão. Objetivou-se estimar as concentrações de clorofila-a em reservatório da região semiárida do Brasil, usando dados simulados de sensor orbital, como suporte à gestão dos recursos hídricos. A área de

  1. Comunidade microbiana e mesofauna edáficas em solo sob caatinga no semi-árido da Paraíba Soil microbial community and mesofauna under dry forest vegetation in the semi-arid region of Paraíba, Brazil

    Directory of Open Access Journals (Sweden)

    Patrícia Carneiro Souto

    2008-02-01

    Full Text Available A atividade biológica do solo é responsável por inúmeras transformações físicas e químicas dos resíduos orgânicos que são depositados, mantendo, assim, a sustentabilidade do ambiente. O presente estudo objetivou avaliar a distribuição da comunidade microbiana e da mesofauna edáfica no semi-árido da Paraíba. Para determinação da população de microrganismos, foram coletadas amostras de solo na profundidade de 0-15 cm. A contagem total de fungos e de bactérias foi realizada em meios de cultura específicos. A extração da mesofauna foi feita pelo método de Berlese-Tullgren modificado. Oscilações no conteúdo de água do solo e na temperatura promoveram variações na população microbiana. A população de fungos foi superior à de bactérias nos dois anos de observação, provavelmente devido ao pH do solo da área de estudo, que é ligeiramente ácido. O índice de diversidade de Shannon (H e o de Pielou (e variaram de acordo com a época de coleta. Os grupos mais freqüentes da mesofauna do solo foram Diptera (42,5 %, Acarinae (40,3 % e Collembola (8,8 %, indicando que esses organismos possuem papel importante na ciclagem de nutrientes em área de Caatinga.The biological soil activity is responsible for several physical and chemical transformations of deposited organic residues, therefore maintaining the environmental sustainability. The aim of this study was to evaluate the distribution of the soil microbial community and mesofauna in a dry forest (Caatinga in the semi-arid region of Paraíba, northeastern Brazil. To determine the microorganism population soil samples from the 0-15 cm soil layer were evaluated. Total counts of fungi and bacteria were evaluated in specific culture media. The Berleusse-Tüllgren modified method was used to extract the soil mesofauna. Oscillations in the soil water content and high temperatures promoted variations in the microbial population. The fungi population was larger than that of

  2. Manejo de colheita e espaçamento da palma-forrageira, em consórcio com sorgo granífero, no Agreste de Pernambuco Harvest managing and plant spacing of spinelles fodder cactus, under grain sorghum intercropping at the semi-arid region of Pernambuco State, Brazil

    Directory of Open Access Journals (Sweden)

    IDERVAL FARIAS

    2000-02-01

    Full Text Available Este trabalho foi realizado na zona semi-árida de Pernambuco e teve como objetivo investigar o efeito de espaçamento, e a freqüência e intensidade de colheitas da palma-forrageira (Opuntia ficus-indica Mill. consorciada com sorgo granífero (Sorghum bicolor (L. Moench. O delineamento experimental foi o de blocos ao acaso em parcelas subdivididas, sendo os espaçamentos alocados nas parcelas principais, e as freqüências e intensidades de colheitas, nas subparcelas. Os resultados são de um período de 12 anos, e as produções de matéria seca de palma, de grãos e restolhos de sorgo foram: 5,23, 1,65 e 2,07; 4,51, 1,30 e 2,10; 2,75, 1,97 e 3,51 t/ha/ano, em espaçamentos de 2,0 m x 1,0 m; 3,0 m x 1,0 m x 0,50 m e 7,0 m x 1,0 m x 0,50 m, respectivamente. A produção de matéria seca foi diferente entre as freqüências de corte, quando foram conservados os artículos primários: 4,08 t/ha/ano na freqüência de quatro anos, e de 3,43 t/ha/ano na freqüência de dois anos. A produção de palma aumentou com o período de crescimento da planta, nas duas intensidades de corte estudadas. A composição química dos artículos de palma e dos restolhos de sorgo foi pouco afetada pelos tratamentos.This trial was carried out in the semi-arid region of Pernambuco, aiming to study plant spacing and harvest frequencies and intensities of forage cactus (Opuntia ficus-indica Mill.. An experimental design in a split plot design was applied, in which plant spacing were used as the main plots and harvest frequencies and intensities as the subplots. Results presented in this work are related to a twelve-year period. The dry matter yields of forage cactus, sorghum grains and stover were: 5.23, 1.65 and 2.07; 4.51, 1.30 and 2.10; 2.75, 1.97 and 3.5 ton/ha/year, for plant spacing 2.0 m x 1.0 m; 3.0 m x 1.0 m x 0.50 m and 7.0 m x 1.0 m x 0.50 m, respectively. Dry matter yield was different between harvest frequencies, when primary articles were conserved: 4

  3. Appropriate technology for sustainable family agriculture in the semi-arid: solar water pumping for located irrigation; Tecnologia apropriada para a agricultura familiar sustentavel do semi-arido brasileiro: bombeamento solar de agua para irrigacao localizada

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Heitor Scalambrini [Universidade Federal de Pernambuco (NAPER/UFPE), Recife, PE (Brazil). Nucleo de Apoio a Projetos de Energias Renovaveis], Email: naper@ufpe.br

    2006-07-01

    Water and energy are the physic factor, which are most influential on the life conditions in the semi-arid rural environment as a whole and in the agriculture production systems in particular. Water is a resource, which - even though not rare - is found in limited quantities and not always is available on the ground surface, meaning that it should be retrieved through either proper wells or deep holes excavated into ground. Therefore, its use should be optimized. In the rural environment to turn water into an available resource in a sufficient amount in order to improve the population life conditions is still a challenge. In the rural semi-arid regions the electric energy distribution is small compared to the other regions of the country. Nevertheless the geographic position of the Brazilian Northeast - close to the equator - adds to this region high levels of insolation - something close to 3,000 hours of sunshine per year - turning this energy resource into a very abundant one. It is known that the use of solar energy, among the use of other resources, has increased the most worldwide in the last decade. The use of photovoltaic cells has increased around 17% per year in the 90's. In the last years several applications, which had the sun as their electric energy resource, were implemented in the rural areas of many countries. The Brazilian Northeast region was the preferred target of programs and projects aiming at the dissemination of the photovoltaic solar technology. Water pumping is one among the most noble applications of the photovoltaic solar technology. There are many pumping systems configurations for either deep or shallow wells, which use either superficial, immerse or floating motor-pumps, which in turn can be driven by either continuum or alternate current. In this work the usage of water pumped with solar energy from Amazon wells (also called 'cacimboes') for small family-based areas of localized irrigation (less than 1 ha), whose main

  4. The effects of clouds and aerosols on net ecosystem CO2 exchange over semi-arid Loess Plateau of Northwest China

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    H. Yu

    2010-05-01

    Full Text Available The impacts of clouds and atmospheric aerosols on the terrestrial carbon cycle at semi-arid Loess Plateau in Northwest China are investigated, by using the observation data obtained at the SACOL (Semi-Arid Climate and Environment Observatory of Lanzhou University site. Daytime (solar elevation angles of larger than 50° NEE of CO2 obtained during the midgrowing season (July–August are analyzed with respect to variations in the diffuse radiation, cloud cover and aerosol optical depth (AOD. Results show a significant impact by clouds and aerosols on the CO2 uptake by the grassland (with smaller LAI values located in a semi-arid region, quite different from areas covered by forests and crops. The light saturation levels in canopy are lower, with a value of about 434.8 W m−2. Thus, under overcast conditions of optically thick clouds, the CO2 uptake increases with increasing clearness index, and a maximum CO2 uptake and light use efficiency of vegetation occur with the clearness index of about 0.37 and lower air temperature. Under other sky conditions the CO2 uptake decreases with the cloudiness but the light use efficiency is enhanced, due to increase in the fraction of diffuse PAR. Additionally, under cloudy conditions, changes in the NEE of CO2 also result from the interactions of many environmental factors, especially the air temperature. In contrast to its response to changes in solar radiation, the carbon uptake shows a negative response to increased AOD. The reason for the difference in the response of the semi-arid grassland from that of the forest and crop lands may be due to the difference in the canopy's architectural structure.

  5. Land use change and carbon cycle in arid and semi-arid lands of East and Central Asia

    Institute of Scientific and Technical Information of China (English)

    Togtohyn; Chuluun; Dennis; Ojima

    2002-01-01

    Dramatic changes in land use have occurred in arid and semi-arid landsof Asia during the 20th century. Grassland conversion into croplands and ecosystem degradation is widespread due to the high growth rate of human population and political reforms of pastoral systems. Rangeland degradation made many parts of this region vulnerable to environmental and political changes. The collapse of the livestock sector in some states of central Asia, expansion of livestock inChina and intensive degradation of grasslands in China are examples of the responses of pastoral systems to these changes over the past decades. Carbon dynamics in this region is highly variable in space and time. Land use/cover changes with widespread reduction of forest and grasslands increased carbon emission from the region.

  6. Pattern selection and hysteresis in the Rietkerk model for banded vegetation in semi-arid environments.

    Science.gov (United States)

    Dagbovie, Ayawoa S; Sherratt, Jonathan A

    2014-10-01

    Banded vegetation is a characteristic feature of semi-arid environments. It occurs on gentle slopes, with alternating stripes of vegetation and bare ground running parallel to the contours. A number of mathematical models have been proposed to investigate the mechanisms underlying these patterns, and how they might be affected by changes in environmental conditions. One of the most widely used models is due to Rietkerk and co-workers, and is based on a water redistribution hypothesis, with the key feedback being that the rate of rainwater infiltration into the soil is an increasing function of plant biomass. Here, for the first time, we present a detailed study of the existence and stability of pattern solutions of the Rietkerk model on slopes, using the software package wavetrain (www.ma.hw.ac.uk/wavetrain). Specifically, we calculate the region of the rainfall-migration speed parameter plane in which patterns exist, and the sub-region in which these patterns are stable as solutions of the model partial differential equations. We then perform a detailed simulation-based study of the way in which patterns evolve when the rainfall parameter is slowly varied. This reveals complex behaviour, with sudden jumps in pattern wavelength, and hysteresis; we show that these jumps occur when the contours of constant pattern wavelength leave the parameter region giving stable patterns. Finally, we extend our results to the case in which a diffusion term for surface water is added to the model equations. The parameter regions for pattern existence and stability are relatively insensitive to small or moderate levels of surface water diffusion, but larger diffusion coefficients significantly change the subdivision into stable and unstable patterns. PMID:25142517

  7. Assessing water availability in a semi-arid watershed of southern India using a semi-distributed model

    Science.gov (United States)

    Perrin, J.; Ferrant, S.; Massuel, S.; Dewandel, B.; Maréchal, J. C.; Aulong, S.; Ahmed, S.

    2012-08-01

    SummaryAppropriate groundwater resource management becomes a priority for the States of the semi-arid southern India. Because of the highly increasing groundwater demand, the number of drought-prone regions where the groundwater resource is classified as over-exploited by the Government is critically increasing. Thus there is a need to develop quantitative methodologies adapted to the regional context that are capable to assess water resources at watershed scale and the impact of management measures. This study demonstrates the calibration and use of an integrated water resource assessment model (SWAT) in an 84 km2 representative semi-arid crystalline watershed of southern India with no perennial surface water source. The model can reproduce (i) the recharge rate estimates derived independently by a groundwater balance computation, (ii) runoff and surface water storage occurring in tanks that spread along the drainage system, (iii) groundwater table fluctuations monitored at a monthly time step. Results show that even if the calibration period (2006-2010) was more humid than long-term average, the watershed is sensitive to the monsoon inter-annual variability with water-stress during the dry years and an associated loss in agricultural production. The impact of these dry years is spatially variable with higher vulnerability for sub-basins having proportionally larger irrigated paddy areas, lower groundwater resource, and/or lower recharge potential (i.e., due to land use and repartition of percolation tanks). The scope for additional recharge by means of managed aquifer recharge structures is limited and demand-side management measures are needed to mitigate pumping. A wishful management objective may be to see groundwater reserves as a supplementary resource in case of monsoon failure and not as the main water resource to be used indiscriminately. SWAT proved to be an adequate modeling framework for the simulation of water resource in semi-arid hard-rock context

  8. Coupling stable isotope and satellite to inform a snow accumulation and melt model for data poor, semi-arid watersheds

    Science.gov (United States)

    Hublart, Paul; Sproles, Eric; Soulsby, Chris; Tetzlaff, Doerthe; Hevía, Andres

    2016-04-01

    At the most basic level watersheds catch, store, and release water. In semi-arid northern central Chile (29°-32°) snow and glacier melt dominate these basic hydrological stages. In this region precipitation is typically limited to three to five events per year that falls as snow in the High Cordillera at elevations above 3000 m a.s.l. The rugged topography and steep gradient makes snowfall rates highly variable in space and time. Despite its critical importance for water supply, high elevation meteorological data and measurements of snowpack are scarce due to limited winter access above 3000 m a.s.l. Due to the critically limited understanding of catch, store, and release processes most conceptual watershed models for this region remain speculative, are prone to over-parameterization, and greatly inhibits hydrological prediction in the region. Focused on two headwater watersheds of the Elqui River basin (1615-6040 m a.s.l., 429-566 km2) this study couples stable isotope and Moderate Resolution Imaging Spectrometer (MODIS) data to develop an improved conceptual model of how semi-arid mountain watersheds catch, store, and release water. MODIS snow-cover and land surface temperature data are used to inform an enhanced temperature-index Snow Accumulation and Melt (SAM) model. The use of remotely-sensed temperature data as input to this model is evaluated by comparison with an interpolated dataset derived from a few available meteorological stations. The outputs from the SAM model are used as inputs to a conceptual catchment model including two water stores (one standing for surface/subsurface processes and the other for deeper groundwater storage). The model is calibrated and evaluated from a Bayesian perspective using discharge data measured at the catchment outlets over a 15-year period (2000-2015). Stable isotope data collected during 2015-2016 is applied to better constrain model outputs. The combination of MODIS-based and isotope-based information proves very

  9. Extensive Green Roof Species and Soilless Media Evaluations in Semi-arid Colorado

    Science.gov (United States)

    In the high elevation, semi-arid climate of Colorado, green roofs have not been scientifically tested. This research examined alternative plant species, soilless media blends and plant interactions on an existing, modular-extensive (shallow, 10 cm deep) green roof in Denver, Colo...

  10. Comparison of groundwater recharge estimation methods for the semi-arid Nyamandhlovu area, Zimbabwe

    NARCIS (Netherlands)

    Sibanda, T.; Nonner, J.C.; Uhlenbrook, S.

    2009-01-01

    The Nyamandhlovu aquifer is the main water resource in the semi-arid Umguza district in Matebeleland North Province in Zimbabwe. The rapid increase in water demand in the city of Bulawayo has prompted the need to quantify the available groundwater resources for sustainable utilization. Groundwater r

  11. Site-specific properties and irreversible vegetation changes in semi-arid grazing systems

    NARCIS (Netherlands)

    Rietkerk, M; vandenBosch, F; vandeKoppel, J

    1997-01-01

    There is an urgent need to develop a mechanistic understanding of how site-specific properties can lead to irreversible vegetation changes. We show, by means of a bifurcation analysis of two mathematical models, how site-specific properties determine the resilience of vegetation changes in semi-arid

  12. Infiltration and planting pits for improved water management and maize yield in semi-arid Zimbabwe

    NARCIS (Netherlands)

    Nyakudya, I.W.; Stroosnijder, L.; Nyagumbo, I.

    2014-01-01

    Realising that rainwater harvesting (RWH) improves crop productivity, smallholder farmers in semi-arid Zimbabwe modified contour ridges traditionally used for rainwater management by digging infiltration pits inside contour ridge channels in order to retain more water in crop fields. However, scient

  13. Understanding hydrological variability for improved water management in the Semi-Arid Karkheh basin, Iran

    NARCIS (Netherlands)

    Masih, I.

    2011-01-01

    This study provides a hydrology based assessment of (surface) water resources and its continuum of variability and change at different spatio-temporal scales in the semi-arid Karkheh Basin, Iran, where water is scarce, competition among users is high and massive water resources development is under

  14. Tillage and farmyard manure efects on crusting and compacting soils at Katumani, Semi-arid Kenya

    NARCIS (Netherlands)

    Biamah, E.K.; Sterk, G.; Stroosnijder, L.

    2008-01-01

    In semi-arid Kenya, the most dominatn soil types are of limited agricultural productivity due to crusting and compaction. The occurence of soil crusting and compaction is attributed to seasonal rainfall characteristics, physical soil properties and bad tillage practices. Soil crusting and compaction

  15. Runoff controlling factors in various sized catchments in a semi-arid Mediterranean environment in Spain

    NARCIS (Netherlands)

    Wit, A.M.W. de

    2001-01-01

    Understanding land degradation in a semi-arid Mediterranean environment is very difficult because of the contributing factors: precipitation, infiltration vegetation cover and discontinuity of flow and the temporal and spatial levels of resolution at which these factors are acting. Therefore it is s

  16. Soil quality improvement for crop production in semi-arid West Africa

    NARCIS (Netherlands)

    Ouédraogo, E.

    2004-01-01

    Soil quality maintenance and crop production improvement in semi-arid West Africa require appropriate cropping technologies, which are ecologically sound and economically viable. Thus, on-farm and on-station experiments have been carried out on the central plateau and in the south of Burkina Faso Th

  17. Contour hedgerows and grass strips in erosion and runoff control in semi-arid Kenya

    NARCIS (Netherlands)

    Kinama, J.M.; Stigter, C.J.; Ong, C.K.; Ng'ang'a, J.K.; Gichuki, F.N.

    2007-01-01

    Most early alley cropping studies in semi-arid Kenya were on fairly flat land while there is an increase in cultivated sloping land. The effectiveness of aging contour hedgerows and grass strips for erosion control on an about 15% slope of an Alfisol was compared. The five treatments were Senna siam

  18. Necrophagous beetles associated with carcasses in a semi-arid environment in northeastern Brazil: implications for forensic entomology.

    Science.gov (United States)

    Mayer, Ana C G; Vasconcelos, Simão D

    2013-03-10

    Data on the ecology and bionomics of necrophagous beetles are scarce in tropical countries despite their relevance in forensic investigations. We performed a survey on the diversity and temporal pattern of colonization of beetles on pig carcasses in a fragment of dry forest in northeastern Brazil. We collected 1550 adults of diverse feeding habits from 12 families, of which 96% had necrophagous and/or copro-necrophagous habits and belonged to four families: Dermestidae, Scarabaeidae, Cleridae and Trogidae. Three species, Dermestes maculatus, Necrobia rufipes and Omorgus suberosus are reported for the first time with an expanded geographical distribution that includes the semi-arid region in Brazil. Adult beetles were collected as early as 24h after death. One endemic species, Deltochilum verruciferum, stood out in terms of numerical dominance and temporal occurrence during different stages of decomposition. Its intimate association with carrion emphasizes their potential role in forensic entomology in the region.

  19. The problems of over exploitation of aquifers in semi-arid areas: characteristics and proposals for mitigation

    International Nuclear Information System (INIS)

    This article presents a general analysis of the problems arising from overexploited aquifers in semi-arid areas, based on research carried out in the Region of Murcia (one of the most over-exploited areas in Europe). Among the negative impacts of this over exploitation are: the drying up of springs, the continuous drawdown of water levels (up to 10 m/y), piezo metric drops (over 30 m in one year if it is a karstic aquifer), an increase in pumping costs (elevating water from a depth of more than 450 m), abandonment of wells, diminishing groundwater reserves, deteriorating water quality, presence of CO2, compartmentalizing of aquifers, etc. A series of internal measures is proposed to alleviate the over exploitation of the region. (Author)

  20. The problems of over exploitation of aquifers in semi-arid areas: characteristics and proposals for mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Estrella, T.

    2014-06-01

    This article presents a general analysis of the problems arising from overexploited aquifers in semi-arid areas, based on research carried out in the Region of Murcia (one of the most over-exploited areas in Europe). Among the negative impacts of this over exploitation are: the drying up of springs, the continuous drawdown of water levels (up to 10 m/y), piezo metric drops (over 30 m in one year if it is a karstic aquifer), an increase in pumping costs (elevating water from a depth of more than 450 m), abandonment of wells, diminishing groundwater reserves, deteriorating water quality, presence of CO{sub 2}, compartmentalizing of aquifers, etc. A series of internal measures is proposed to alleviate the over exploitation of the region. (Author)

  1. Land cover/land use change in semi-arid Inner Mongolia: 1992-2004

    International Nuclear Information System (INIS)

    The semi-arid grasslands in Inner Mongolia (IM) are under increasing stress owing to climate change and rapid socio-economic development in the recent past. We investigated changes in land cover/land use and landscape structure between 1992 and 2004 through the analysis of AVHRR and MODIS derived land cover data. The scale of analysis included the regional level (i.e. the whole of IM) as well as the level of the dominant biomes (i.e. the grassland and desert). We quantified proportional change, rate of change and the changes in class-level landscape metrics using the landscape structure analysis program FRAGSTATS. The dominant land cover types, grassland and barren, 0.47 and 0.27 million km2, respectively, have increased proportionally. Cropland and urban land use also increased to 0.15 million km2 and 2197 km2, respectively. However, the results further indicated increases in both the homogeneity and fragmentation of the landscape. Increasing homogeneity was mainly related to the reduction in minority cover types such as savanna, forests and permanent wetlands and increasing cohesion, aggregation index and clumpy indices. Conversely, increased fragmentation of the landscape was based on the increase in patch density and the interspersion/juxtaposition index (IJI). It is important to note the socio-economic growth in this fragile ecosystem, manifested by an increasing proportion of agricultural and urban land use not just at the regional level but also at the biome level in the context of regional climate change and increasing water stress.

  2. Modeled Impacts of Chronic Wasting Disease on White-Tailed Deer in a Semi-Arid Environment

    Science.gov (United States)

    Hewitt, David G.; DeYoung, Charles A.; DeYoung, Randy W.; Schnupp, Matthew J.

    2016-01-01

    White-tailed deer are a culturally and economically important game species in North America, especially in South Texas. The recent discovery of chronic wasting disease (CWD) in captive deer facilities in Texas has increased concern about the potential emergence of CWD in free-ranging deer. The concern is exacerbated because much of the South Texas region is a semi-arid environment with variable rainfall, where precipitation is strongly correlated with fawn recruitment. Further, the marginally productive rangelands, in combination with erratic fawn recruitment, results in populations that are frequently density-independent, and thus sensitive to additive mortality. It is unknown how a deer population in semi-arid regions would respond to the presence of CWD. We used long-term empirical datasets from a lightly harvested (2% annual harvest) population in conjunction with 3 prevalence growth rates from CWD afflicted areas (0.26%, 0.83%, and 2.3% increases per year) via a multi-stage partially deterministic model to simulate a deer population for 25 years under four scenarios: 1) without CWD and without harvest, 2) with CWD and without harvest, 3) with CWD and male harvest only, and 4) with CWD and harvest of both sexes. The modeled populations without CWD and without harvest averaged a 1.43% annual increase over 25 years; incorporation of 2% annual harvest of both sexes resulted in a stable population. The model with slowest CWD prevalence rate growth (0.26% annually) without harvest resulted in stable populations but the addition of 1% harvest resulted in population declines. Further, the male age structure in CWD models became skewed to younger age classes. We incorporated fawn:doe ratios from three CWD afflicted areas in Wisconsin and Wyoming into the model with 0.26% annual increase in prevalence and populations did not begin to decline until ~10%, ~16%, and ~26% of deer were harvested annually. Deer populations in variable environments rely on high adult

  3. Soil Moisture Variability and its Effects on Herbage Production in Semi-arid Rangelands of Kenya

    International Nuclear Information System (INIS)

    Results obtained from recent studies focused on rangelands potential as influenced by human activity and climatic factors in the semi-arid and arid pastoral ecosystems of Northern Kenya indicated great temporal and spatial forage production variability. The objective of the studies was to document primary production in relation to water stress (drought), herbivory and direct human activities. Efforts also focused on finding possibilities of increasing productivity while conserving the finite resources for sustainable use. Laboratory, field and numerical methods were employed over several seasons and years. Forb and grass production was more variable than that of the browse (dwarf shrub) layer. Compared to forbs and dwarf shrubs, the grass layer contributed less to the total production in all seasons, indicating that the region had less potential for grazers compared to browsers. Spatial-temporal variation in rangeland carrying capacity reflected the great spatial heterogeneity in vegetation types and production. Similarly, seasonal differences were very evident, with highest estimates in the long rainy and the lowest during the dry and short rainy seasons, respectively. Factors limiting rangeland production potential were identified to be moisture deficiency, resource-use conflicts, an increasing and partially sedentarised nomadic population, overgrazing, tree felling, and land degradation (desert encroachment). Measures that can improve rangeland production potential and provide a better way of life for the inhabitants of the region include: (a) identification of land degradation (e.g. by means of bio-indicators and Geographical Information Systems, GIS); (b) technical interventions (i.e. soil and water conservation, restoration of degraded areas, fodder production); (c) social-economic interventions (i.e. resolution of resource-use conflicts, alleviation of poverty, infrastructure development improvement of livestock marketing channels etc.) and (d) continued

  4. An improved conceptual understanding of snowmelt and groundwater dynamics in the semi-arid Andes

    Science.gov (United States)

    Sproles, Eric; Hevia, Andres; Soulsby, Chris; Tetzlaff, Doerthe

    2016-04-01

    The contribution of snowmelt to groundwater has long been recognized as an important component of the hydrological cycle in semi-arid northern central Chile (29°-32°S). Despite its importance as a water resource, this transition to groundwater remains poorly understood. Climatically, the High Cordillera in northern central Chile receives approximately 10 times as much annual precipitation as the valley bottoms, falling almost exclusively as snow above 3500 m during the winter months. Geologically, the High Cordillera is characterized by steep topography and a highly dissected landscape underlain by bedrock. Groundwater stores in the mountain headwaters are assumed to be constrained to the valley bottoms. The current working hypothesis of watershed processes in the High Cordillera describes fluxes of spring melt moving through the hillslope via local flowpaths to valley aquifers that recharge streams throughout the headwater reaches. Previous studies in the region indicate Pre-Cordilleran aquifers, located in lower elevation dry ephemeral valleys, are hydrologically disconnected from the High Cordillera. These watersheds have no seasonal snowpack, and recharge occurs primarily during infrequent rain events. These isolated Pre-Cordilleran aquifers serve as an important water resource for rural residents and infrastructure. We present stable isotope, geochemical, and groundwater level data from the wet El Niño winter of 2015 that suggests a topographically disconnected aquifer in the Pre-Cordillera received considerable recharge from High Cordillera snowmelt. These novel findings are indicative of deep groundwater flow paths between the Pre- and High Cordillera during the wet winter and spring of 2015, and improve the conceptual understanding of hydrological processes in the region. Additionally, these results will directly benefit groundwater management in the Pre-Cordillera and better inform modeling efforts in the High Cordillera. While this study is limited to

  5. Situação nutricional e alimentar de pré-escolares no semi-árido da Bahia (Brasil: II ­ Hipovitaminose A Nutritional status of pre-school children of the semi-arid region of Bahia (Brazil: II ­ Vitamin A deficiency

    Directory of Open Access Journals (Sweden)

    Leonor M.P. Santos

    1996-02-01

    Full Text Available Foram estudados 754 pré-escolares de áreas urbanas de sete municípios do semi-árido do Estado Bahia, Brasil, com o objetivo de determinar a prevalência da hipovitaminose A e sua associação com a idade, sexo, renda em salário-mínimo, escolaridade materna e adequação dietética em vitamina A. Na amostra estudada não se registrou nenhum caso de sinais e/ou sintomas de xeroftalmia durante o exame clínico-oftalmológico. Em 563 crianças foi possível a coleta de sangue para determinação de retinol sérico; encontrou-se um valor médio de 20,3 µg/dl (DP=10,8µg/dl e uma prevalência de 15,3% de níveis deficientes (abaixo de 10,0 µg/dl. Em todos os sete municípios estudados a prevalência de retinol sérico deficiente foi superior a 5,0% que é nível crítico proposto pela OMS para considerar a hipovitaminose A como problema de saúde pública. A distribuição de retinol sérico encontrada não teve relação com o sexo das crianças, mas com a idade, diminuindo a prevalência de níveis deficientes e baixos na medida em que a idade aumenta. Não se encontrou associação entre renda familiar per capita ou escolaridade materna e a prevalência de níveis de retinol deficiente. Os resultados de consumo alimentar provenientes do inquérito recordatório de 24h mostraram que apenas 8% das crianças consumiram quantidades adequadas de retinol ou de seus precursores; 66% ingeriam abaixo da metade e quase 35% delas não chegaram a ingerir nem um quarto da quantidade recomendada para sua faixa etária. A carência de vitamina A deve ser considerada como problema de saúde pública severo, tanto pela alta prevalência de níveis deficientes de retinol em todos os municípios como também pela dimensão da inadequação dietética.A survey of 754 preschool children was undertaken in the urban areas of seven small towns of the semi-arid region of Bahia, Northeastern Brazil, to determine the prevalence of vitamin A deficiency, as well as its

  6. An integrative approach to characterize hydrological processes and water quality in a semi-arid watershed in Northeastern Brazil

    Science.gov (United States)

    Franklin, M. R.; Fernandes, N.; Veiga, L. H. S.; Melo, L. R.; Santos, A. C. S.; Araujo, V. P.

    2014-12-01

    Arid and semi-arid regions face serious challenges in the management of scarce water resources. This situation tends to become worse with the increasing population growth rates and consequently increasing water demand. Groundwater is the most important water resource in these areas and, therefore, the sustainability of its use depends on the effectiveness in which it is managed, both in terms of quantity and quality. The Caetité Experimental Basin (CEB), located in a semi-arid region of Northeastern Brazil, faces not only the challenges associated with water scarcity, but also changes in landscape and potential contamination processes due to mining activity. The only active uranium production center in Brazil (URA) is located in this watershed and the sustainability of mining and milling operations as well as the survival of the local community are highly dependent on the availability of groundwater resources. Hydrogeological studies in this area are scarce, and the potential contamination and overexploitation of groundwater can not be ruled out. Therefore, a national project was launched in order to improve the understanding and quantification of the interaction between the hydrogeological system and human health. The methodological approach involved hydrological and geochemical monitoring and characterization of the CEB, use of isotopic techniques, groundwater modeling, water quality diagnosis and human health risk assessment due to water ingestion. The results suggested that the groundwater in the CEB are not totally connected, with evidence of a mixture of recent and old waters. The Na-Ca-HCO3-Cl is the dominant water type (50%) followed by Ca-Na-HCO3-Cl water type (17%). The relevant non-radioactive contaminants are Mn, F, NO3 and Ba, mostly from natural origin, with the exception of NO3 that could be associated with the livestock activities. The estimated effective doses due to groundwater ingestion containing radionuclides are below the recommended

  7. Two-Source Energy Balance Model Evaluation for Mapping Evapotranspiration on the Semi- arid Southern High Plains

    Science.gov (United States)

    Gowda, P. H.; Chavez, J. L.; Colaizzi, P. D.; Evett, S. R.; Howell, T. A.; Copeland, K.

    2007-05-01

    Evapotranspiration (ET) is an essential component of the water balance and a major consumptive use of irrigation water and precipitation on cropland. In this study, we applied the Two-Source Energy Balance (T-SEB) model to estimate hourly ET from Landsat Thematic Mapper (TM) data for the semi-arid Southern High Plains of the United States where more than 90 percent of the groundwater withdrawals are used for irrigation. For this purpose, a Landsat TM image covering a major portion of the Southern High Plains (parts of Texas Panhandle and northeastern New Mexico) was acquired for 23 July 2006 for the overpass at 11:26 AM CST. Atmospheric correction on the TM imagery was done using MODTRAN, an atmospheric radiative transfer model. Comprehensive ground-truth data were collected to develop a detailed land use map showing major crops grown in the region. Performance of the T SEB model was evaluated by comparing mapped ET data with measured hourly ET data on five weighing lysimeters at Bushland, TX [35 Deg. 11' N, 102 Deg. 06' W; 1,170 m elevation MSL] managed by the Conservation and Production Research Laboratory, USDA-ARS. Lysimeter-measured ET rates varied from 0.24 to 0.71 mm/h. Comparison of estimated hourly mapped ET values with lysimetric measurements had an accuracy within 6% of the measured ET (r2=0.99), with a root mean squared error of 0.03 mm/h. These results support the use of the T-SEB model for the semi-arid Southern High Plains; however, more evaluation is needed for different agroclimatological conditions in the region.

  8. Physical-chemical determinant properties of biological communities in continental semi-arid waters.

    Science.gov (United States)

    da Rocha, Francisco Cleiton; de Andrade, Eunice Maia; Lopes, Fernando Bezerra; de Paula Filho, Francisco José; Filho, José Hamilton Costa; da Silva, Merivalda Doroteu

    2016-08-01

    Throughout human history, water has undergone changes in quality. This problem is more serious in dry areas, where there is a natural water deficit due to climatic factors. The aims of this study, therefore, were (i) to verify correlations between physical attributes, chemical attributes and biological metrics and (ii) from the biological attributes, to verify the similarity between different points of a body of water in a tropical semi-arid region. Samples were collected every 2 months, from July 2009 to July 2011, at seven points. Four physical attributes, five chemical attributes and four biological metrics were investigated. To identify the correlations between the physicochemical properties and the biological metrics, hierarchical cluster analysis (HCA) and canonical correlation analysis (CCA) were applied. Nine classes of phytoplankton were identified, with the predominance of species of cyanobacteria, and ten families of macroinvertebrates. The use of HCA resulted in the formation of three similar groups, showing that it was possible to reduce the number of sampling points when monitoring water quality with a consequent reduction in cost. Group I was formed from the waters at the high end of the reservoir (points P1, P2 and P3), group II by the waters from the middle third (points P4 and P5), and group III by the waters from the lower part of the reservoir (points P6 and P7). Richness of the phytoplanktons Cyanophyceae, Chorophyceae and Bacillariophyceae was the attribute which determined dissimilarity in water quality. Using CCA, it was possible to identify the spatial variability of the physicochemical attributes (TSS, TKN, nitrate and total phosphorus) that most influence the metrics of the macroinvertebrates and phytoplankton present in the water. Low macroinvertebrate diversity, with a predominance of indicator families for deterioration in water quality, and the composition of phytoplankton showing a predominance of cyanobacteria, suggests greater

  9. Impacts of groundwater extraction on salinization risk in a semi-arid floodplain

    Science.gov (United States)

    Alaghmand, S.; Beecham, S.; Hassanli, A.

    2013-12-01

    In the lower River Murray in Australia, a combination of a reduction in the frequency, duration and magnitude of natural floods, rising saline water tables in floodplains, and excessive evapotranspiration have led to an irrigation-induced groundwater mound forcing the naturally saline groundwater onto the floodplain. It is during the attenuation phase of floods that these large salt accumulations are likely to be mobilised and discharged into the river. This has been highlighted as the most significant risk in the Murray-Darling Basin and the South Australian Government and catchment management authorities have subsequently developed salt interception schemes (SIS). The aim of these schemes is to reduce the hydraulic gradient that drives the regional saline groundwater towards the River Murray. This paper investigates the interactions between a river (River Murray in South Australia) and a saline semi-arid floodplain (Clark's floodplain) that is significantly influenced by groundwater lowering due to a particular SIS. The results confirm that groundwater extraction maintains a lower water table and a higher amount of fresh river water flux to the saline floodplain aquifer. In terms of salinity, this may lead to less solute stored in the floodplain aquifer. This occurs through three mechanisms, namely extraction of the solute mass from the system, reducing the saline groundwater flux from the highland to the floodplain and changing the floodplain groundwater regime from a losing to a gaining one. It is shown that groundwater extraction is able to remove some of the solute stored in the unsaturated zone and this can mitigate the floodplain salinity risk. A conceptual model of the impact of groundwater extraction on floodplain salinization has been developed.

  10. Research Note:Derivation of temperature lapse rates in semi-arid south-eastern Arizona

    Directory of Open Access Journals (Sweden)

    R. C. Harlow

    2004-01-01

    Full Text Available Ecological and hydrological modelling at the regional scale requires distributed information on weather variables, and temperature is important among these. In an area of basin and range topography with a wide range of elevations, such as south-eastern Arizona, measurements are usually available only at a relatively small number of locations and elevations, and temperatures elsewhere must be estimated from atmospheric lapse rate. This paper derives the lapse rates to estimate maximum, minimum and mean daily temperatures from elevation. Lapse rates were calculated using air temperatures at 2 m collected during 2002 at 18 locations across south-eastern Arizona, with elevations from 779 to 2512 m. The lapse rate predicted for the minimum temperature was lower than the mean environmental lapse rate (MELR, i.e. 6 K km–1, whereas those predicted for the mean and maximum daily temperature were very similar to the MELR. Lapse rates were also derived from radiosonde data at 00 and 12 UTC (5 pm and 5 am local time, respectively. The lapse rates calculated from radiosonde data were greater than those from the 2 m measurements, presumably because the effect of the surface was less. Given temperatures measured at Tucson airport, temperatures at the other sites were predicted using the different estimates of lapse rates. The best predictions of temperatures used the locally predicted lapse rates. In the case of maximum and mean temperature, using the MELR also resulted in accurate predictions. Keywords: near surface lapse rates, semi-arid climate, mean minimum and maximum temperatures, basin and range topography

  11. Physical-chemical determinant properties of biological communities in continental semi-arid waters.

    Science.gov (United States)

    da Rocha, Francisco Cleiton; de Andrade, Eunice Maia; Lopes, Fernando Bezerra; de Paula Filho, Francisco José; Filho, José Hamilton Costa; da Silva, Merivalda Doroteu

    2016-08-01

    Throughout human history, water has undergone changes in quality. This problem is more serious in dry areas, where there is a natural water deficit due to climatic factors. The aims of this study, therefore, were (i) to verify correlations between physical attributes, chemical attributes and biological metrics and (ii) from the biological attributes, to verify the similarity between different points of a body of water in a tropical semi-arid region. Samples were collected every 2 months, from July 2009 to July 2011, at seven points. Four physical attributes, five chemical attributes and four biological metrics were investigated. To identify the correlations between the physicochemical properties and the biological metrics, hierarchical cluster analysis (HCA) and canonical correlation analysis (CCA) were applied. Nine classes of phytoplankton were identified, with the predominance of species of cyanobacteria, and ten families of macroinvertebrates. The use of HCA resulted in the formation of three similar groups, showing that it was possible to reduce the number of sampling points when monitoring water quality with a consequent reduction in cost. Group I was formed from the waters at the high end of the reservoir (points P1, P2 and P3), group II by the waters from the middle third (points P4 and P5), and group III by the waters from the lower part of the reservoir (points P6 and P7). Richness of the phytoplanktons Cyanophyceae, Chorophyceae and Bacillariophyceae was the attribute which determined dissimilarity in water quality. Using CCA, it was possible to identify the spatial variability of the physicochemical attributes (TSS, TKN, nitrate and total phosphorus) that most influence the metrics of the macroinvertebrates and phytoplankton present in the water. Low macroinvertebrate diversity, with a predominance of indicator families for deterioration in water quality, and the composition of phytoplankton showing a predominance of cyanobacteria, suggests greater

  12. Impacts of urbanization on groundwater quality and recharge in a semi-arid alluvial basin

    Science.gov (United States)

    Carlson, Mark A.; Lohse, Kathleen A.; McIntosh, Jennifer C.; McLain, Jean E. T.

    2011-10-01

    SummaryThe management of groundwater resources is paramount in semi-arid regions experiencing urban development. In the southwestern United States, enhancing recharge of urban storm runoff has been identified as a strategy for augmenting groundwater resources. An understanding of how urbanization may impact the timing of groundwater recharge and its quality is a prerequisite for mitigating water scarcity and identifying vulnerability to contamination. We sampled groundwater wells along the Rillito Creek in southern Arizona that had been previously analyzed for tritium in the late 1980s to early 1990s and analyzed samples for tritium ( 3H) and helium-3 ( 3H/ 3He) to evaluate changes in 3H and age date groundwaters. Groundwater samples were also analyzed for chlorofluorocarbons (CFCs) and basic water quality metrics. Substantial changes in 3H values from waters sampled in the early 1990s compared to 2009 were identified after accounting for radioactive decay and indicate areas of rapid recharge. 3H- 3He groundwater ages ranged from 22 years before 2009 to modern recharge. CFC-11, -12 and -113 concentrations were anomalously high across the basin, and non-point source pollution in runoff and/or leaky infrastructure was identified as the most plausible source of this contamination. CFCs were strongly and positively correlated to nitrate ( r2 = 0.77) and a mobile trace metal, nickel ( r2 = 0.71), suggesting that solutes were derived from a similar source. Findings from this study suggest new waters from urban non-point sources are contributing to groundwater recharge and adversely affecting water quality. Reducing delivery of contaminants to areas of focused recharge will be critical to protect future groundwater resources.

  13. The role of upland wetlands in modulating snowmelt runoff in the semi-arid Andes

    Science.gov (United States)

    Hevia, Andres; Sproles, Eric; Soulsby, Chris; Tetzlaff, Doerthe

    2016-04-01

    The wetlands, or bofedales, of semi-arid northern central Chile (29°-32°S) provide a critical store of water that modulate spring snowmelt runoff. Water released from bofedales helps sustain flows throughout the dry portions of the year, providing fresh water to downstream residents and a robust tourist, agricultural, and mining economy. In the Río Claro watershed (30°S, 1515 km2, 800m to 5500 m a.s.l.) a series fourteen bofedales have formed at natural choke points in the valley bottoms of the headwater reaches. The highly erosive dynamic of this watershed provides ample sediment, and some of these bofedales are up to 30 m deep. Annual precipitation in the region is limited to 4-6 events annually that fall primarily as snow at elevations above 3500 m. The subsurface storage of the headwaters is limited by the steep terrain of the headwater catchments that are devoid of soils and primarily underlain by granite bedrock. Downstream, irrigated area has increased by 200% between 1985 and 2005, driven by the cultivation of table grapes for export. For over 70 years local water managers have flooded the bodfedales during spring runoff to augment late season flow when irrigation demand peaks. While this low-tech strategy has worked in the past, a recent 8-year drought has raised concerns over long-term water security. We apply geophysical and geographic measurements, water quality, and stable isotopic tracers to calculate the volume of water storage and residence times in the bofedales of Río Claro. This information will be used to evaluate the reliability of the bofedale system as compared to a proposed reservoir in the headwaters of the Río Claro. Additionally, estimating the storage and residence times of the will help reduce uncertainty for modeling efforts currently underway in Río Claro.

  14. Large-scale hydrological modelling in the semi-arid north-east of Brazil

    Science.gov (United States)

    Güntner, Andreas

    2002-07-01

    Semi-arid areas are, due to their climatic setting, characterized by small water resources. An increasing water demand as a consequence of population growth and economic development as well as a decreasing water availability in the course of possible climate change may aggravate water scarcity in future, which often exists already for present-day conditions in these areas. Understanding the mechanisms and feedbacks of complex natural and human systems, together with the quantitative assessment of future changes in volume, timing and quality of water resources are a prerequisite for the development of sustainable measures of water management to enhance the adaptive capacity of these regions. For this task, dynamic integrated models, containing a hydrological model as one component, are indispensable tools. The main objective of this study is to develop a hydrological model for the quantification of water availability in view of environmental change over a large geographic domain of semi-arid environments. The study area is the Federal State of Ceará (150 000 km2) in the semi-arid north-east of Brazil. Mean annual precipitation in this area is 850 mm, falling in a rainy season with duration of about five months. Being mainly characterized by crystalline bedrock and shallow soils, surface water provides the largest part of the water supply. The area has recurrently been affected by droughts which caused serious economic losses and social impacts like migration from the rural regions. The hydrological model Wasa (Model of Water Availability in Semi-Arid Environments) developed in this study is a deterministic, spatially distributed model being composed of conceptual, process-based approaches. Water availability (river discharge, storage volumes in reservoirs, soil moisture) is determined with daily resolution. Sub-basins, grid cells or administrative units (municipalities) can be chosen as spatial target units. The administrative units enable the coupling of Wasa in

  15. Perched groundwater-surface interactions and their consequences in stream flow generation in a semi-arid headwater catchment

    Science.gov (United States)

    Molenat, Jerome; Bouteffeha, Maroua; Raclot, Damien; Bouhlila, Rachida

    2013-04-01

    In semi-arid headwater catchment, it is usually admitted that stream flow comes predominantly from Hortonian overland flow (infiltration excess overland flow). Consequently, subsurface flow processes, and especially perched or shallow groundwater flow, have not been studied extensively. Here we made the assumption that perched groundwater flow could play a significant role in stream flow generation in semi-arid catchment. To test this assumption, we analyzed stream flow time series of a headwater catchment in the Tunisian Cap Bon region and quantified the flow fraction coming from groundwater discharge and that from overland flow. Furthermore, the dynamics of the perched groundwater was analyzed, by focusing on the different perched groundwater-surface interaction processes : diffuse and local infiltration, diffuse exfiltration, and direct groundwater discharge to the stream channel. This work is based on the 2.6 km² Kamech catchment (Tunisia), which belongs to the long term Mediterranean hydrological observatory OMERE (Voltz and Albergel, 2002). Results show that even though Hortonian overland flow was the main hydrological process governing the stream flow generation, groundwater discharge contribution to the stream channel annually accounted for from 10% to 20 % depending on the year. Furthermore, at some periods, rising of groundwater table to the soil surface in bottom land areas provided evidences of the occurrence of saturation excess overland flow processes during some storm events. Reference Voltz , M. and Albergel , J., 2002. OMERE : Observatoire Méditerranéen de l'Environnement Rural et de l'Eau - Impact des actions anthropiques sur les transferts de masse dans les hydrosystèmes méditerranéens ruraux. Proposition d'Observatoire de Recherche en Environnement, Ministère de la Recherche.

  16. Qualitative soil moisture assessment in semi-arid Africa: the role of experience and training on inter-rater reliability

    Directory of Open Access Journals (Sweden)

    M. Rinderer

    2015-03-01

    Full Text Available Soil and water management is particularly relevant in semi-arid regions to enhance agricultural productivity. During periods of water scarcity soil moisture differences are important indicators of the soil water deficit and are traditionally used for allocating water resources among farmers of a village community. Here we present a simple, inexpensive soil wetness classification scheme based on qualitative indicators which one can see or touch on the soil surface. It incorporates the local farmers' knowledge on the best soil moisture conditions for seeding and brick making in the semi-arid environment of the study site near Arusha, Tanzania. The scheme was tested twice in 2014 with farmers, students and experts (April: 40 persons, June: 25 persons for inter-rater reliability, bias of individuals and functional relation between qualitative and quantitative soil moisture values. During the test in April farmers assigned the same wetness class in 46% of all cases while students and experts agreed in about 60% of all cases. Students who had been trained in how to apply the method gained higher inter-rater reliability than their colleagues with only a basic introduction. When repeating the test in June, participants were given improved instructions, organized in small sub-groups, which resulted in a higher inter-rater reliability among farmers. In 66% of all classifications farmers assigned the same wetness class and the spread of class assignments was smaller. This study demonstrates that a wetness classification scheme based on qualitative indicators is a robust tool and can be applied successfully regardless of experience in crop growing and education level when an in-depth introduction and training is provided. The use of a simple and clear layout of the assessment form is important for reliable wetness class assignments.

  17. Qualitative soil moisture assessment in semi-arid Africa - the role of experience and training on inter-rater reliability

    Science.gov (United States)

    Rinderer, M.; Komakech, H. C.; Müller, D.; Wiesenberg, G. L. B.; Seibert, J.

    2015-08-01

    Soil and water management is particularly relevant in semi-arid regions to enhance agricultural productivity. During periods of water scarcity, soil moisture differences are important indicators of the soil water deficit and are traditionally used for allocating water resources among farmers of a village community. Here we present a simple, inexpensive soil wetness classification scheme based on qualitative indicators which one can see or touch on the soil surface. It incorporates the local farmers' knowledge on the best soil moisture conditions for seeding and brick making in the semi-arid environment of the study site near Arusha, Tanzania. The scheme was tested twice in 2014 with farmers, students and experts (April: 40 persons, June: 25 persons) for inter-rater reliability, bias of individuals and functional relation between qualitative and quantitative soil moisture values. During the test in April farmers assigned the same wetness class in 46 % of all cases, while students and experts agreed on about 60 % of all cases. Students who had been trained in how to apply the method gained higher inter-rater reliability than their colleagues with only a basic introduction. When repeating the test in June, participants were given improved instructions, organized in small subgroups, which resulted in a higher inter-rater reliability among farmers. In 66 % of all classifications, farmers assigned the same wetness class and the spread of class assignments was smaller. This study demonstrates that a wetness classification scheme based on qualitative indicators is a robust tool and can be applied successfully regardless of experience in crop growing and education level when an in-depth introduction and training is provided. The use of a simple and clear layout of the assessment form is important for reliable wetness class assignments.

  18. Qualitative soil moisture assessment in semi-arid Africa: the role of experience and training on inter-rater reliability

    Science.gov (United States)

    Rinderer, M.; Komakech, H.; Müller, D.; Seibert, J.

    2015-03-01

    Soil and water management is particularly relevant in semi-arid regions to enhance agricultural productivity. During periods of water scarcity soil moisture differences are important indicators of the soil water deficit and are traditionally used for allocating water resources among farmers of a village community. Here we present a simple, inexpensive soil wetness classification scheme based on qualitative indicators which one can see or touch on the soil surface. It incorporates the local farmers' knowledge on the best soil moisture conditions for seeding and brick making in the semi-arid environment of the study site near Arusha, Tanzania. The scheme was tested twice in 2014 with farmers, students and experts (April: 40 persons, June: 25 persons) for inter-rater reliability, bias of individuals and functional relation between qualitative and quantitative soil moisture values. During the test in April farmers assigned the same wetness class in 46% of all cases while students and experts agreed in about 60% of all cases. Students who had been trained in how to apply the method gained higher inter-rater reliability than their colleagues with only a basic introduction. When repeating the test in June, participants were given improved instructions, organized in small sub-groups, which resulted in a higher inter-rater reliability among farmers. In 66% of all classifications farmers assigned the same wetness class and the spread of class assignments was smaller. This study demonstrates that a wetness classification scheme based on qualitative indicators is a robust tool and can be applied successfully regardless of experience in crop growing and education level when an in-depth introduction and training is provided. The use of a simple and clear layout of the assessment form is important for reliable wetness class assignments.

  19. The dominant role of semi-arid ecosystems in the trend and variability of the land CO2 sink

    DEFF Research Database (Denmark)

    Ahlström, Anders; Raupach, Michael R.; Schurgers, Guy;

    2015-01-01

    The growth rate of atmospheric carbon dioxide (CO2) concentrations since industrialization is characterized by large interannual variability, mostly resulting from variability in CO2 uptake by terrestrial ecosystems (typically termed carbon sink). However, the contributions of regional ecosystems...... regions. Whereas the mean sink is dominated by highly productive lands (mainly tropical forests), the trend and interannual variability of the sink are dominated by semi-arid ecosystems whose carbon balance is strongly associated with circulation-driven variations in both precipitation and temperature....

  20. Tillage for soil and water conservation in the semi-arid tropics

    OpenAIRE

    Hoogmoed, W. B.

    1999-01-01

    Soil tillage is the manipulation of soil which is generally considered as necessary to obtain optimum growth conditions for a crop. In the same time the resulting modification of soil structure has serious implications for the behaviour of the soil to erosive forces by water and wind. In Chapter 1 an introduction is given to the most important aspects: the objectives of tillage, the conflicting requirements set to tillage, the characteristics of soil and water conservation in the semi-arid tr...

  1. Farm level adoption decisions of soil and water management technologies in semi-arid Eastern Kenya

    OpenAIRE

    Bett, Charles

    2004-01-01

    In this paper the conceptual framework of individual farmers' adoption decisions of new agricultural technologies is used to identify factors that influence adoption modified fanya juu terraces in semi-arid eastern Kenya. The adoption decision model was specified using farm and farmers' characteristics and technology characteristics though likely to influence farmers' adoption behaviour. To test intensity of adoption a Torbit model was specified and estimated. Results of logit regression anal...

  2. Who Engages in Water Scarcity Conflicts? A Field Experiment with Irrigators in Semi-arid Africa

    OpenAIRE

    D'Exelle, Ben; Lecoutere, Els; Van Campenhout, Bjorn

    2010-01-01

    Does water scarcity induce conflict? And who would engage in a water scarcity conflict? In this paper we look for evidence of the relation between water scarcity and conflictive behavior. With a framed field experiment conducted with smallholder irrigators from semi-arid Tanzania that replicates appropriation from an occasionally scarce common water flow we assess what type of water users is more inclined to react in conflictive way to scarcity. On average, water scarcity induces selfish appr...

  3. The challenges of rehabilitating denuded patches of a semi-arid environment in Kenya

    OpenAIRE

    Mganga, K.Z.; Nyangito, M.M.; Musimba, N.K.R.; Nyariki, D.M.; Mwangombe, A.W.; Ekaya, W.N.; Muiri, W.M.; Clavel, D; Francis, J.; Kaufmann, Von, R.; Verhagen, J.

    2010-01-01

    Land degradation is a major problem in the semi-arid environments of Sub-Saharan Africa. Fighting land degradation is essential to ensure the sustainable and long-term productivity of the habited semiarid lands. In Kenya, grass reseeding technology has been used to combat land degradation. However, despite the use of locally adapted perennial grass species namely Cenchrus ciliaris (African foxtail grass), Eragrostis superba (Maasai love grass) and Enteropogon macrostachyus (Bush rye) failure ...

  4. Geochemical Processes Controlling the Generation and Environmental Impacts of Acid Mine Drainage in Semi Arid Conditions

    OpenAIRE

    Magombedze, Chris

    2006-01-01

    This study evaluates the geochemical processes that control the geochemistry of acid mine drainage in semi arid conditions. The central objective is to characterise and understand the evolution of acid mine drainage and its potential environmental impacts on the Mazowe River sub-catchment, in north east Zimbabwe. The work is based on a case study at three neighbouring metal sulphide mines, namely Trojan Nickel Mine, Mazowe Gold Mine and Iron Duke Pyrites.The methodology used in this research ...

  5. Understanding runoff processes in a semi-arid environment through isotope and hydrochemical hydrograph separations

    OpenAIRE

    Camacho Suarez, V. V.; Saraiva Okello, A. M. L.; Wenninger, J.W.; Uhlenbrook, S.

    2015-01-01

    The understanding of runoff generation mechanisms is crucial for the sustainable management of river basins such as the allocation of water resources or the prediction of floods and droughts. However, identifying the mechanisms of runoff generation has been a challenging task, even more so in arid and semi-arid areas where high rainfall and streamflow variability, high evaporation rates, and deep groundwater reservoirs may increase the complexity of hydrological process dyna...

  6. Understanding runoff processes in a semi-arid environment through isotope and hydrochemical hydrograph separations

    OpenAIRE

    V. V. Camacho; Saraiva Okello, A. M. L.; Wenninger, J.W.; Uhlenbrook, S.

    2015-01-01

    The understanding of runoff generation mechanisms is crucial for the sustainable management of river basins such as the allocation of water resources or the prediction of floods and droughts. However, identifying the mechanisms of runoff generation has been a challenging task, even more so in arid and semi-arid areas where high rainfall and streamflow variability, high evaporation rates, and deep groundwater reservoirs increase the complexity of hydrologica...

  7. Spatial variations of shallow and deep soil moisture in the semi-arid Loess Plateau, China

    OpenAIRE

    Yang, L; Wei, W.; Chen, L.; Jia, F.; B. Mo

    2012-01-01

    Soil moisture in deep soil layers is an important relatively stable water resource for vegetation growth in the semi-arid Loess Plateau of China. Characterizing the spatial variations of deep soil moisture with respect to the topographic conditions has significant importance for vegetation restoration. In this study, we focused on analyzing the spatial variations and factors influencing soil moisture content (SMC) in shallow (0–2 m) and deep (2–8 m) soil layers, based on soil moisture observa...

  8. Nursery pre-conditioning of plants for revegetation, gardening and landscaping in semi-arid environments

    OpenAIRE

    Franco Leemhuis, José Antonio; Martínez Sánchez, Juan José; Fernández Hernández, Juan Antonio; Bañón Arias, Sebastián del Pilar; Ochoa Rego, Jesús; Vicente Colomer, María José

    2010-01-01

    In landscaping and xerogardening projects, under semi-arid conditions, appropriate techniques used in the nursery during seedling production are crucial for the establishment, survival and subsequent growth of plants after transplanting (Figure 1). Morphological and anatomical adaptations in seedlings include reductions in shoot height and/or leaf area, rises in root-collar diameter and root growth potential and, often, a reduction in the shoot:root ratio; in addition, there are physiological...

  9. Inventory of Semi-Arid Rangelands in South Texas with LANDSAT Data

    OpenAIRE

    Everitt, J. H.; Richardson, A.J.; Wiegand, C. L.

    1981-01-01

    A 39,000-ha semi-arid rangeland test site in Starr and Zapata Counties, Texas, was used to compare rangeland inventory and other landuse categories estimated by digital pattern recognition methods (maximum likelihood ratio classification) with percentages estimated from a ground-correlated print enlarged to 1:100,000 scale from a LANDSAT color composite transparency. Five land-use categories were identified (grassland, mixed brush rangeland, saline rangeland, cropland, and water). We found a ...

  10. Geochemical Weathering Increases Lead Bioaccessibility in Semi-Arid Mine Tailings

    OpenAIRE

    Hayes, Sarah M.; Webb, Sam M.; Bargar, John R.; O'Day, Peggy A; Maier, Raina M.; Chorover, Jon

    2012-01-01

    Mine tailings can host elevated concentrations of toxic metal(loid)s that represent a significant hazard to surrounding communities and ecosystems. Eolian transport, capable of translocating small (micrometer-sized) particles, can be the dominant mechanism of toxic metal dispersion in arid or semi-arid landscapes. Human exposure to metals can then occur via direct inhalation or ingestion of particulates. The fact that measured doses of total lead (Pb) in geomedia correlate poorly with blood P...

  11. Timing and climatic drivers for glaciation across semi-arid western Himalayan-Tibetan orogen

    Science.gov (United States)

    Dortch, Jason M.; Owen, Lewis A.; Caffee, Marc W.

    2013-10-01

    Mapping and forty-seven new 10Be ages help define the timing of glaciation in the Ladakh and Pangong Ranges in Northwest India. Five new local glacial stages are defined for the Ladakh Range. From oldest to youngest these include: the Ladakh-4 glacial stage at 81 ± 20 ka; the Ladakh-3 glacial stage (not dated); the Ladakh-2 glacial stage at 22 ± 3 ka; the Ladakh-1 glacial stage (not dated); and the Ladakh Cirque glacial stage at 1.8 ± 0.4 ka. Three local glacial stages are defined for the Pangong Range, which include: the Pangong-2 glacial stage at 85 ± 15 ka; the Pangong-1 glacial stage at 40 ± 3 ka; and the Pangong Cirque glacial stage at 0.4 ± 0.3 ka. The new 10Be ages are combined with 645 recalculated 10Be ages from previous studies to develop the first regional framework of glaciation across the dryland regions of the Greater Himalaya, Transhimalaya, Pamir and Tian Shan at the western end of the Himalayan-Tibetan orogen. Nineteen regional glacial stages are recognized that are termed semi-arid western Himalayan-Tibetan stages (SWHTS). These include: SWHTS 9 at 311 ± 32 ka; SWHTS 7 at 234 ± 44 ka [tentative]; SWHTS 6 at 146 ± 18 ka; SWHTS 5E at 121 ± 11 ka; SWHTS 5A at 80 ± 5 ka; SWHTS 5A- at 72 ± 8 ka; SWHTS 4 at 61 ± 5 ka; SWHTS 3 at 46 ± 4 ka; SWHTS 2F at 30 ± 3 ka; SWHTS 2E at 20 ± 2 ka; SWHTS 2D at 16.9 ± 0.7 ka; SWHTS 2C at 14.9 ± 0.8 ka; SWHTS 2B at 13.9 ± 0.5 ka; SWHTS 2A at 12.2 ± 0.8 ka; SWHTS 1E at 8.8 ± 0.3 ka [tentative]; SWHTS 1D at 6.9 ± 0.2 ka [tentative]; SWHTS 1C at 3.8 ± 0.6 ka; SWHTS 1B at 1.7 ± 0.2 ka; and SWHTS 1A at 0.4 ± 0.1 ka. Regional glacial stages older than 21 ka are broadly correlated with strong monsoons. SWHTS that are 21 ka or younger, have smaller uncertainties and broadly correlate with global ice volume given by marine Oxygen Isotope Stages, and northern hemisphere climatic events (Oldest Dryas, Older Dryas, Younger Dryas, Roman Humid Period, and Little Ice Age).

  12. Groundwater Recharge Evaluation in Semi-Arid Northeast Mexico in Response to Projected Climate Change

    Science.gov (United States)

    Wolaver, B. D.

    2007-12-01

    This research evaluates the effects of projected climate change on mountain recharge in the semi-arid Cuatrocinegas Basin (CCB) of northeast Mexico. The CCB UNESCO Biosphere Reserve is located in Coahuila, Mexico (~27° N, ~102° W) and includes > 500 springs that discharge from a regional flow system to wetlands with > 70 endemic species and to an irrigation network. This study tests the hypothesis that projected climate changes will reduce CCB recharge. In CCB, ~75% of annual precipitation (~220 mm at 700 m, ~400 mm at 2350 m) falls between May and October and ~40% falls during the North American Monsoon in June, July, and August. Environmental isotopes indicate aquifer residence times of > 50 years. Stable isotopes (O and H) show that mountain precipitation (at an elevation of ~1170 to 2350 m) dominates groundwater recharge. Recharge is insignificant at lower- elevation valleys that cover the majority of the study area due to high evapotranspiration rates. A Cl--balance water-budget recharge analysis estimates a spatially distributed recharge rate of ~1 to 3% of precipitation to provide at least 35x106 m3/year spring discharge (as measured in canals that drain dozens of springs). IPCC AR4 climate projections predict an annual temperature increase of 3.0 to 3.5°C and an annual precipitation decrease of 5 to 10% for Subregion CNA (located adjacent to CCB) by 2099. During June to August, models project a temperature increase of 3.5 to 4.0°C and a precipitation increase of 0 to 5%. Although global and regional circulation models evaluate mountain regions poorly, a first-order evaluation of climate projections on CCB recharge is needed input to develop effective long-term groundwater management policies. Climate projections suggest that the minimum elevation at which recharge occurs in CCB may increase by ~615 m to 1785 m, which would limit recharge to the highest mountain elevations. If annual precipitation is reduced by 5 to 10% and temperatures increase as

  13. High spatial resolution remote sensing imagery improves GPP predictions in disturbed, semi-arid woodlands

    Science.gov (United States)

    Krofcheck, D. J.; Eitel, J.; Vierling, L. A.; Schulthess, U.; Litvak, M. E.

    2012-12-01

    Climate across the globe is changing and consequently the productivity of terrestrial vegetation is changing with it. Gross primary productivity (GPP) is an integral part of the carbon cycle, yet challenging to measure everywhere, all the time. Efforts to estimate GPP in the context of climate change are becoming continually more salient of the need for models sensitive to the heterogeneous nature of drought and pest induced disturbance. Given the increased availability of high spatial resolution remotely sensed imagery, their use in ecosystem scale GPP estimation is becoming increasingly viable. We used a simple linear model with inputs derived from RapidEye time series data (5 meter spatial resolution) as compared to MODIS inputs (250 meter spatial resolution) to estimate GPP in intact and girdled PJ woodland to simulate drought and pest induced disturbance. An area equal to the MODIS pixels measured was aggregated using RapidEye data centered on the flux towers for comparison purposes. We generated four model runs, two using only MODIS or RapidEye spectral vegetation indices (VIs) and two using MODIS and RapidEye VIs combined at both the control and disturbed tower site. Our results suggest that for undisturbed regions, MODIS derived VIs perform better than the higher spatial resolution RapidEye VIs when a moisture sensitive index is incorporated into the model (RMSE of 17.51for MODIS vs. 22.71 for RapidEye). Modeling GPP in disturbed regions however benefits from the inclusion of high spatial resolution data (RMSE of 14.83 for MODIS vs. 14.70 for RapidEye). This discrepancy may have to do with the disparate scale of a MODIS pixel and the size of the tower fetch. Our results suggest that the best source of VI's for the modeling GPP in semi-arid woodlands depends on the level of disturbance in the landscape. Given that the rate and extent of drought and insect induced mortality events in terrestrial forests are projected to increase with our changing climate

  14. Spatiotemporal modelling of groundwater extraction in semi-arid central Queensland, Australia

    Science.gov (United States)

    Keir, Greg; Bulovic, Nevenka; McIntyre, Neil

    2016-04-01

    The semi-arid Surat Basin in central Queensland, Australia, forms part of the Great Artesian Basin, a groundwater resource of national significance. While this area relies heavily on groundwater supply bores to sustain agricultural industries and rural life in general, measurement of groundwater extraction rates is very limited. Consequently, regional groundwater extraction rates are not well known, which may have implications for regional numerical groundwater modelling. However, flows from a small number of bores are metered, and less precise anecdotal estimates of extraction are increasingly available. There is also an increasing number of other spatiotemporal datasets which may help predict extraction rates (e.g. rainfall, temperature, soils, stocking rates etc.). These can be used to construct spatial multivariate regression models to estimate extraction. The data exhibit complicated statistical features, such as zero-valued observations, non-Gaussianity, and non-stationarity, which limit the use of many classical estimation techniques, such as kriging. As well, water extraction histories may exhibit temporal autocorrelation. To account for these features, we employ a separable space-time model to predict bore extraction rates using the R-INLA package for computationally efficient Bayesian inference. A joint approach is used to model both the probability (using a binomial likelihood) and magnitude (using a gamma likelihood) of extraction. The correlation between extraction rates in space and time is modelled using a Gaussian Markov Random Field (GMRF) with a Matérn spatial covariance function which can evolve over time according to an autoregressive model. To reduce computational burden, we allow the GMRF to be evaluated at a relatively coarse temporal resolution, while still allowing predictions to be made at arbitrarily small time scales. We describe the process of model selection and inference using an information criterion approach, and present some

  15. Effects of Phosphorus Application in Different Soil Layers on Root Growth, Yield, and Water-Use Efifciency of Winter Wheat Grown Under Semi-Arid Conditions

    Institute of Scientific and Technical Information of China (English)

    KANG Li-yun; YUE Shan-chao; LI Shi-qing

    2014-01-01

    Deep phosphorus application can be a usefull measure to improve crops’ performance in semi-arid regions, but more knowledge of both its general effects and effects on speciifc crops is required to optimize treatments. Thus, the aims of this study were to evaluate the effects of phosphorus (P) application at different soil layers on root growth, grain yield, and water-use efifciency (WUE) of winter wheat grown on the semi-arid Loess Plateau of China and to explore the relationship between root distribution and grain yield. The experiment consisted of four P treatments in a randomized complete block design with three replicates and two cultivars: one drought-sensitive (Xiaoyan 22, XY22) and one drought-tolerant (Changhan 58, CH58). The four P treatments were no P (control, CK), surface P (SP), deep P (DP), and deep-band P application (DBP). CH58 produced larger and deeper root systems, and had higher grain yields and WUE, under the deep P treatments (DP and DBP) than under SP, clearly showing that deep P placement had beneifcial effects on the drought-tolerant cultivar. In contrast, the grain yield and root growth of XY22 did not differ between DP or DBP and SP treatments. Further, root dry weight (RW) and root length (RL) in deep soil layer (30-100 cm) were closely positively correlated with grain yield and WUE of CH58 (but not XY22), highlighting the connections between a well-developed subsoil root system and both high grain yield and WUE for the drought-tolerant cultivar. WUE correlated strongly with grain yield for both cultivars (r=0.94,P<0.001). In conclusion, deep application of P fertilizer is a practical and feasible means of increasing grain yield and WUE of rainfed winter wheat in semi-arid regions, by promoting deep root development of drought-tolerant cultivars.

  16. Radical scavenging, antioxidant and cytotoxic activity of Brazilian Caatinga plants.

    Science.gov (United States)

    David, Juceni P; Meira, Marilena; David, Jorge M; Brandão, Hugo N; Branco, Alexsandro; de Fátima Agra, M; Barbosa, M Regina V; de Queiroz, Luciano P; Giulietti, Ana M

    2007-04-01

    Extracts of 32 plants from the Brazilian northeastern semi-arid region called Caatinga were evaluated through DPPH radical scavenging assay, beta-carotene bleaching, and brine shrimp lethality tests (BST). Among the extracts studied Byrsonima cf. gardneriana, Mascagnia coriacea, Cordia globosa, Diodia apiculata and Hypenia salzmannii showed the highest activities in DPPH radical scavenging test. In the beta-carotene bleaching test the highest activities were observed for Passiflora cincinnata, Chamaecrista repens, B. cf. gardneriana, Rollinia leptopetala, Serjania glabrata, Diospyros gaultheriifolia, C. globosa, Mimosa ophtalmocentra, M. coriacea and Lippia cf. microphylla. In contrast, R. leptopetala, Zornia cf. brasiliensis and Leonotis nepetifolia were the most active species in the BST.

  17. Radical scavenging, antioxidant and cytotoxic activity of Brazilian Caatinga plants.

    Science.gov (United States)

    David, Juceni P; Meira, Marilena; David, Jorge M; Brandão, Hugo N; Branco, Alexsandro; de Fátima Agra, M; Barbosa, M Regina V; de Queiroz, Luciano P; Giulietti, Ana M

    2007-04-01

    Extracts of 32 plants from the Brazilian northeastern semi-arid region called Caatinga were evaluated through DPPH radical scavenging assay, beta-carotene bleaching, and brine shrimp lethality tests (BST). Among the extracts studied Byrsonima cf. gardneriana, Mascagnia coriacea, Cordia globosa, Diodia apiculata and Hypenia salzmannii showed the highest activities in DPPH radical scavenging test. In the beta-carotene bleaching test the highest activities were observed for Passiflora cincinnata, Chamaecrista repens, B. cf. gardneriana, Rollinia leptopetala, Serjania glabrata, Diospyros gaultheriifolia, C. globosa, Mimosa ophtalmocentra, M. coriacea and Lippia cf. microphylla. In contrast, R. leptopetala, Zornia cf. brasiliensis and Leonotis nepetifolia were the most active species in the BST. PMID:17331673

  18. Agricultural sustainability in the semi-arid Near East

    Directory of Open Access Journals (Sweden)

    F. Hole

    2007-05-01

    Full Text Available Agriculture began in the eastern Mediterranean Levantine Corridor about 11000 years ago toward the end of the Younger Dryas when aridity had diminished wild food resources. During the subsequent Climatic Optimum, agricultural villages spread rapidly but subsequent climatic changes on centennial to millennial scales resulted in striking oscillations in settlement, especially in marginal areas. Natural climate change thus alternately enhanced and diminished the agricultural potential of the land. Growing populations and more intensive land us, both for agriculture and livestock, have led to changes in the structure of vegetation, hydrology, and land quality. Over the millennia, political and economic interventions, warfare and incursions by nomadic herding tribes all impacted sustainability of agriculture and the ability of the land to supports its populations. In much of the region today, agricultural land use is not sustainable given existing technology and national priorities. The Near Eastern case is instructive because of the quality of information, the length of the record, and the pace of modern change.

  19. Agricultural sustainability in the semi-arid Near East

    Directory of Open Access Journals (Sweden)

    F. Hole

    2006-07-01

    Full Text Available Agriculture began in the eastern Mediterranean Levantine Corridor about 11 000 years ago toward the end of the Younger Dryas when aridity had diminished wild food resources. During the subsequent Climatic Optimum, agricultural villages spread rapidly but subsequent climatic changes on centennial to millennial scales resulted in striking oscillations in settlement, especially in marginal areas. Natural climate change thus alternately enhanced and diminished the agricultural potential of the land. Growing populations and more intensive land use, both for agriculture and livestock, have led to changes in the structure of vegetation, hydrology, and land quality. Over the millennia, political and economic interventions, warfare and incursions by nomadic herding tribes all impacted sustainability of agriculture and the ability of the land to support its populations. In much of the region today, agricultural land use is not sustainable given existing technology and national priorities. The Near Eastern case is instructive because of the quality of information, the length of the record, and the pace of modern change.

  20. Management of Meloidogyne incognita with Chemicals and Cultivars in Cotton in a Semi-Arid Environment.

    Science.gov (United States)

    Wheeler, T A; Siders, K T; Anderson, M G; Russell, S A; Woodward, J E; Mullinix, B G

    2014-06-01

    Management of Meloidogyne incognita (root-knot nematode) in cotton in the United States was substantially affected by the decision to stop production of aldicarb by its principle manufacturer in 2011. The remaining commercially available tools to manage M. incognita included soil fumigation, nematicide seed treatments, postemergence nematicide application, and cultivars partially resistant to M. incognita. Small plot field studies were conducted on a total of nine sites from 2011-2013 to examine the effects of each of these tools alone or in combinations, on early season galling, late-season nematode density in soil, yield, and value ($/ha = lint value minus chemical costs/ha). The use of a partially resistant cultivar resulted in fewer galls/root system at 35 d after planting in eight of nine tests, lower root-knot nematode density late in the growing season for all test sites, higher lint yield in eight of nine sites, and higher value/ha in six of nine sites. Galls per root were reduced by aldicarb in three of nine sites and by 1,3-dichloropropene (1,3-D) in two of eight sites, relative to the nontreated control (no insecticide or nematicide treatment). Soil fumigation reduced M. incognita density late in the season in three of nine sites. Value/ha was not affected by chemical treatment in four of nine sites, but there was a cultivar × chemical interaction in four of nine sites. When value/ha was affected by chemical treatment, the nontreated control had a similar value to the treatment with the highest value/ha in seven of eight cultivar-site combinations. The next "best" value/ha were associated with seed treatment insecticide (STI) + oxamyl and aldicarb (similar value to the highest value/ha in six of eight cultivar-site combinations). The lowest valued treatment was STI + 1,3-D. In a semi-arid region, where rainfall was low during the spring for all three years, cultivars with partial resistance to M. incognita was the most profitable method of managing root

  1. Simple, spatial and predictive approach for cereal yield prediction in the semi-arid areas

    Science.gov (United States)

    Toumi, Jihad; Khabba, Said; Er-Raki, Salah; Le page, Michel; Chahbi Bellakanji, Aicha; Lili Chabaane, Zohra; Ezzahar, Jamal; Zribi, Mehrez; Jarlan, Lionel

    2016-04-01

    The objective is to develop a simple, spatial and predictive approach of dry matter (DM) and grain yield (GY) of cereal in the semi-arid areas. The proposed method is based on the three efficiencies model of Monteith (1972). This approach summarizes the transformation of solar radiation to the dry matter (DM) by the climate (ɛc), interception (ɛi) and conversion (ɛconv) efficiencies. The method combines the maximum of ɛi and ɛconv (noted ɛimax and ɛconvmax) into a single parameter denoted ɛmax, calculating as a function of cumulating growing degree day (CGDD). Also, the stress coefficient ks, which affects the conversion of solar radiation to the biomass was calculated by the surface temperature or the water balance at the root zone. In addition, the expression of ks has been improved by the consideration of the results achieved by deficit irrigation (AquaCrop and STICS models) which showed that the value of ks from 0.7 to 1 didn't affect significantly the cereal production. For the partitioning of the dry matter developed, between straw and grain, the method proposed calculates a variable Harvest Index coefficient (HI). HI is deducted from CGDD and HI0max (maximal final harvest Index in the region of study). Finally, the approach calculates DM depending Satellite Information (NDVI and surface temperature Ts) and climatic data (solar radiation and air temperature). In the case of no availability of Ts, the amount of irrigation is required to calculate ks. Until now, the developed model has been calibrated and validated on the irrigated area R3, located 40 Km east of Marrakech. The evolutions of DM and GY were reproduced satisfactorily. R2 and RMSE are respectively 0.98 and 0.35 t/ha and 0.98 and 0.19 t/ha, respectively. Currently, additional tests are in progress on data relating to the Kairouan plain of Tunisia.

  2. Evaporative loss from irrigated interrows in a highly advective semi-arid agricultural area

    Science.gov (United States)

    Agam, Nurit; Evett, Steven R.; Tolk, Judy A.; Kustas, William P.; Colaizzi, Paul D.; Alfieri, Joseph G.; McKee, Lynn G.; Copeland, Karen S.; Howell, Terry A.; Chávez, Jose L.

    2012-12-01

    Agricultural productivity has increased in the Texas High Plains at the cost of declining water tables, putting at risk the sustainability of the Ogallala Aquifer as a principal source of water for irrigated agriculture. This has led area producers to seek alternative practices that can increase water use efficiency (WUE) through more careful management of water. One potential way of improving WUE is by reducing soil evaporation (E), thus reducing overall evapotranspiration (ET). Before searching for ways to reduce E, it is first important to quantify E and understand the factors that determine its magnitude. The objectives of this study were (1) to quantify E throughout part of the growing season for irrigated cotton in a strongly advective semi-arid region; (2) to study the effects of LAI, days after irrigation, and measurement location within the row on the E/ET fraction; and (3) to study the ability of microlysimeter (ML) measures of E combined with sap flow gage measures of transpiration (T) to accurately estimate ET when compared with weighing lysimeter ET data and to assess the E/T ratio. The research was conducted in an irrigated cotton field at the Conservation & Production Research Laboratory of the USDA-ARS, Bushland, TX. ET was measured by a large weighing lysimeter, and E was measured by 10 microlysimeters that were deployed in two sets of 5 across the interrow. In addition, 10 heat balance sap flow gages were used to determine T. A moderately good agreement was found between the sum E + T and ET (SE = 1 mm or ˜10% of ET). It was found that E may account for >50% of ET during early stages of the growing season (LAI < 0.2), significantly decreasing with increase in LAI to values near 20% at peak LAI of three. Measurement location within the north-south interrows had a distinct effect on the diurnal pattern of E, with a shift in time of peak E from west to east, a pattern that was governed by the solar radiation reaching the soil surface. However, total

  3. Avaliação antropométrica e consumo alimentar em crianças menores de cinco anos residentes em um município da região do semiárido nordestino com cobertura parcial do programa bolsa família Anthropometric assessment and food intake of children younger than 5 years of age from a city in the semi-arid area of the Northeastern region of Brazil partially covered by the bolsa família program

    Directory of Open Access Journals (Sweden)

    Silvia Regina Dias Médici Saldiva

    2010-04-01

    Full Text Available OBJETIVO: Avaliar as condições de saúde e nutrição de crianças menores de cinco anos, e associar a qualidade do consumo alimentar aos beneficiários do Programa Bolsa Família de um município do semiárido brasileiro. MÉTODOS: Foram avaliadas 189 crianças, a partir de uma amostragem de 411 domicílios do município de João Câmara (RN. Foram realizadas medidas de peso e altura, e levantadas às condições socioeconômicas e determinação dos hábitos alimentares. Para o diagnóstico nutricional das crianças foram utilizados os indicadores Peso/Idade, Altura/Idade e Peso/Altura. Análises univariadas foram realizadas e modelos bivariados e multivariados de regressão logística foram construídos para testar a hipótese do estudo. RESULTADOS: O déficit de peso foi de 4,3% e o de altura de 9,9%, e o excesso de peso de 14,0%. Não foram encontradas diferenças estatísticas entre o estado nutricional de crianças beneficiárias e não beneficiárias do Programa Bolsa Família. Em ambos os grupos, os consumos de frutas, verduras e legumes foram baixos e semelhantes entre si. As crianças do programa bolsa família têm risco três vezes maior de consumir guloseimas (OR 3,06 - IC 1,35-6,95. CONCLUSÃO: Os resultados do padrão de consumo alimentar dessa população apontam para uma situação de "risco alimentar e nutricional", e exigem uma intervenção por parte dos profissionais de saúde para a promoção da alimentação saudável.OBJECTIVE: The objective of this study was to assess the health and nutritional status of children under five years of age and to associate the quality of the foods consumed with the Bolsa Família Program in a city located in the Brazilian semi-arid region. METHOD: A total of 189 children from a sample of 411 households in the city of João Câmara (RN were assessed. Weight and height were measured and socioeconomic and food habits were determined with the use of questionnaires. The nutritional status of

  4. Latent heat loss and sweat gland histology of male goats in an equatorial semi-arid environment

    Science.gov (United States)

    de Melo Costa, Cíntia Carol; Maia, Alex Sandro Campos; Neto, José Domingues Fontenele; Oliveira, Steffan Edward Octávio; de Queiroz, João Paulo Araújo Fernandes

    2014-03-01

    The objective of this work was to quantify the heat loss by cutaneous evaporation of goats in an equatorial semi-arid environment. The latent heat loss from the body surfaces of these ten undefined breed goats was measured using a ventilated capsule in sun and shade and in the three body regions (neck, flank and hindquarters). Skin samples from these three regions were histologically analyzed to relate the quantity of sweat glands, the area of sweat glands and the epithelium thickness of each of these regions to the heat loss by cutaneous evaporation of the examined goats. The epithelium thickness that was measured varied significantly for body regions with different quantities and areas of sweat glands ( P sweat glands from the flank had the biggest area (43330.51 ± 778.71 μm2) and quantity per square centimeter (390 ± 9 cm-2). After the animals were exposed to sun, the flanks lost the greatest amount of heat by cutaneous evaporation (73.03 ± 1.75 W m-2) and possessed the highest surface temperatures (39.47 ± 0.18 °C). The histological characteristics may have influenced the heat loss by cutaneous evaporation that was observed in the flank region after the animals were exposed to sun.

  5. Fotossensibilização primária em eqüídeos e ruminantes no semi-árido causada por Froelichia humboldtiana (Amaranthaceae Primary photosensitization in equidae and ruminants in the Brazilian semi-arid caused by Froelichia humboldtiana (Amaranthaceae

    Directory of Open Access Journals (Sweden)

    Luciano A. Pimentel

    2007-01-01

    colocados na mesma pastagem com F. humboldtiana por um período de 44 dias. A égua, que não tinha áreas de pele despigmentadas não apresentou lesões, no entanto o potro desenvolveu dermatite nas áreas brancas de pele 25 dias após o início do pastejo. Após serem retirados da pastagem o potro recuperou-se totalmente em 15 dias. Estes experimentos indicam que F. humboldtiana causa fotossensibilização primária em animais domésticos. A ausência de lesões nos animais que ingeriram a planta após ser coletada e mantida em geladeira sugere que a planta perde sua toxicidade depois da coleta. A ausência de lesões oculares características da intoxicação por furocumarinas sugere que F. humboldtiana contém derivados da naftodiantrona, similares aos encontrados em Fagopyrum esculentum e Hypericum perforatum que não causam lesões oculares.Photosensitization is common in the Brazilian semiarid, affecting mainly horses, but also donkeys, mules, sheep and cattle. The dermatitis affects mainly non pigmented skin, and the animals recover after being withdrawn from the pastures. To demonstrate the etiology of the disease, Froelichia humboldtiana (Roem. et Schult. Seub., collected in the field one or two times a week and kept in the refrigerator for 1-4 days, was administered for 30 or more days as the only food ad libitum to 2 donkeys and one white sheep, and as the only forage ad libitum, to one white horse. No clinical signs were observed in those animals, and serum activities of aspartate-aminotransferase (AST, alanine-aminotransferase (AST, and gamma-glutamyltransferase (GGT were within normal ranges. In another experiment, one sheep was tied by a rope, during the day, in a pasture of exclusively F. humboldtiana for a 26 days period. Skin lesions characteristic of photosensitization appeared 4-5 days after the start of the experiment and became severe until day 26. After the withdrawal of the animal from the pasture on day 26 it fully recovered within 30 days. In

  6. Understanding environmental drivers in the regulation of soil respiration dynamics after fire in semi-arid ecosystems

    Science.gov (United States)

    Muñoz-Rojas, Miriam; Lewandrowski, Wolfgang; Erickson, Todd E.; Dixon, Kingsley W.; Merritt, David J.

    2016-04-01

    Keywords: Pilbara, soil CO2 efflux, soil C, soil moisture, soil temperature Introduction Soil respiration (Rs) has become a major research focus given the increase in atmospheric CO2 emissions and the large contribution of these CO2 fluxes from soils (Van Groenigen et al., 2014). In addition to its importance in the global C cycle, Rs is a fundamental indicator of soil health and quality that reflects the level of microbial activity and provides an indication of the ability of soils to support plant growth (Oyonarte et al., 2012; Munoz-Rojas et al., 2015). Wildfires can have a significant impact on Rs rates, with the scale of the impact depending on environmental factors such as temperature and moisture, and organic C content in the soil. Vegetation cover can have a significant effect on regulating organic C contents; and while advances are made into understanding the effects of fire on organic C contents and CO2 fluxes (Granged et al., 2011; Willaarts et al., 2015; Muñoz-Rojas et al., 2016), there is limited knowledge of the variability of Rs across ecosystem types, vegetation communities, and responses to fire. In this research we aimed to assess the impacts of a wildfire on the soil CO2 fluxes and soil respiration in a semi-arid ecosystem of Western Australia (Pilbara biogeographical region), and to understand the main environmental drivers controlling these fluxes in different vegetation types. The study has application for other arid and semi-arid regions of the world. Methods The study area was selected following a wildfire that affected 25 ha in February 2014. Twelve plots were established in the burnt site (B) within a 400 m2 area, and 12 plots in an adjacent unburnt control site. At each site, three plots were installed below the canopy of each of the most representative vegetation types of the areas: Eucalyptus trees, Acacia shrubs and Triodia grasses, and three on bare soil. Soil sampling and measurement of soil CO2 efflux, temperature and moisture were

  7. Avaliação da atividade antibacteriana e prospecção fitoquímica de Solanum paniculatum Lam. e Operculina hamiltonii (G. Don D. F. Austin & Staples, do semi-árido paraibano Evaluation of antibacterial activity and phytochemical prospection of Solanum paniculatum Lam. and Operculina hamiltonii (G. Don D. F. Austin & Staples from the semi-arid region of Paraíba State, Brazil

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    K.M.S Lôbo

    2010-06-01

    Full Text Available Devido ao aparecimento de populações de parasitos resistentes, as drogas farmacêuticas, alternativas de controle, estão sendo pesquisadas utilizando plantas medicinais. O objetivo deste estudo foi avaliar a atividade antibacteriana e realizar a análise fitoquímica do extrato etanólico de duas espécies do semi-árido paraibano, Solanum paniculatum Lam. e Operculina hamiltonii (G. Don D. F. Austin & Staples. As referidas espécies são muito utilizadas pela população rural contra verminoses gastrintestinais de ovinos. A prospecção fitoquímica foi obtida a partir dos extratos etanólicos para análise dos constituintes químicos existentes nas duas espécies. As análises dos extratos indicaram a presença de taninos flobabênicos, flavononóis, flavononas e alcalóides em ambas as espécies. A atividade antibacteriana foi determinada inicialmente pelo método de difusão em cavidade. A espécie S. paniculatum apresentou atividade contra Staphylococcus aureus (ATCC 12692, Escherichia coli (ATCC 25922 e Pseudomonas aeruginosa (ATCC 15442, no entanto O. hamintonii não demonstrou atividade contra as linhagens bacterianas testadas.The emergence of resistant parasite populations has led to the study of pharmaceutical drugs, which represent an alternative control. This study aimed to evaluate the antibacterial activity and to perform the phytochemical analysis of the ethanol extract from two species belonging to the semi-arid region of Paraíba State, Brazil: Solanum paniculatum Lam. and Operculina hamiltonii (G. Don D. F. Austin & Staples. Such species have been largely used by the rural population against ovine gastrointestinal helminthes. Phytochemical prospection was obtained from ethanol extracts for analysis of chemical compounds present in both species. Extract analyses indicated the presence of condensed tannins, flavonols, flavanones, and alkaloids in both species. The antibacterial activity was initially determined by the cavity

  8. Relações entre a concentração de íons e a salinidade de águas subterrâneas e superficiais, visando à irrigação, no sertão de Pernambuco Relationship between ions concentration and salinity of subsurface and surface waters for irrigation in the semi-arid region of Pernambuco State, Brazil

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    José Nunes Filho

    2000-01-01

    Full Text Available Objetivando-se verificar as relações entre a condutividade elétrica de águas subterrâneas e superficiais (CEa, em dS m-1 a 25ºC e a concentração dos íons: Na+, Ca++ Mg2+ e Cl-, em mmol c L-1, procedeu-se à análise de regressão desses parâmetros em 175 amostras, sendo 75 de águas subterrâneas e 100 de águas superficiais, em 33 municípios do Sertão de Pernambuco. Os resultados evidenciam que os elementos: Na+, Ca2+ + Mg2+ e Cl-, podem ser estimados com bastante confiabilidade, através de equações do tipo: Y= a + bx, conforme discriminação a seguir: a águas subterrâneas; (Na+ = - 0,710 + 4,765(CEa, R² = 0,91; (Ca2+ + Mg2+ = 0,287 + 4,673(CEa, R² = 0,83; (Cl- = - 0,569 + 6,152(CEa, R²= 0,93 e b águas superficiais; (Na+ = - 0,666 + 5,072(CEa, R² = 0,94; (Ca2+ + Mg2+ = 0,978 + 3,223(CEa, R² = 0,78; (Cl- = - 0,874 + 6,890(CEa, R² = 0,94.The objective of the study was to determine the relationship between the electrical conductivity of subsurface and surface water (ECw in dS/m at 25ºC and the ion concentration of Na+, Ca2+ + Mg2+ and C1- (in mmol c L-1. The study was based on 75 and 100 samples collected from subsurface and surface waters, respectively, in 33 counties in the semi-arid region of the Pernambuco State. Results showed that elements Na+, Ca2+ + Mg2+ and C1- may be estimated by a single linear regression of the type, Y = a + bx, as described below: a subsurface water; (Na+ = - 0.710 + 4.765(ECw, R² = 0.91; (Ca2+ + Mg2+ = 0.287 + 4.673 (ECw, R² = 0.83; (C1- = - 0.569 + 6.152 (ECw, R² = 0.93 and b surface water; (Na+ = - 0.666 + 5.072 (ECw, R² = 0.94; (Ca2+ + Mg2+ = 0.978 + 3.223 (ECw, R² = 0 78; (C1- = - 0.874 + 6.890 (ECw, R²= 0.94.

  9. Geochemical Weathering Increases Lead Bioaccessibility in Semi-Arid Mine Tailings

    Science.gov (United States)

    Hayes, Sarah M.; Webb, Sam M.; Bargar, John R.; O'Day, Peggy A.; Maier, Raina M.; Chorover, Jon

    2012-01-01

    Mine tailings can host elevated concentrations of toxic metal(loid)s that represent a significant hazard to surrounding communities and ecosystems. Eolian transport, capable of translocating small (micrometer-sized) particles, can be the dominant mechanism of toxic metal dispersion in arid or semi-arid landscapes. Human exposure to metals can then occur via direct inhalation or ingestion of particulates. The fact that measured doses of total lead (Pb) in geomedia correlate poorly with blood Pb levels highlights a need to better resolve the precise distribution of molecularly-speciated metal-bearing phases in the complex particle mixtures. Species distribution controls bioaccessibility, thereby directly impacting health risk. This study seeks to correlate Pb-containing particle size and mineral composition with lability and bioaccessibility in mine tailings subjected to weathering in a semi-arid environment. We employed X-ray absorption spectroscopy (XAS) and X-ray fluorescence (XRF), coupled with sequential chemical extractions, to study Pb speciation in tailings from the semi-arid Arizona Klondyke State Superfund Site. Representative samples ranging in pH from 2.6 to 5.4 were selected for in-depth study of Pb solid-phase speciation. The principle lead-bearing phase was plumbojarosite (PbFe6(SO4)4(OH)12), but anglesite (PbSO4) and iron oxide-sorbed Pb were also observed. Anglesite, the most bioavailable mineral species of lead identified in this study, was enriched in surficial tailings samples, where Pb concentrations in the clay size fraction were 2–3 times higher by mass relative to bulk. A mobile and bioaccessible Pb phase accumulates in surficial tailings, with a corresponding increase in risk of human exposure to atmospheric particles. PMID:22553941

  10. Recovery of microbial community structure and functioning after wildfire in semi-arid environments: optimising methods for monitoring and assessment

    Science.gov (United States)

    Muñoz-Rojas, Miriam; Martini, Dylan; Erickson, Todd; Merritt, David; Dixon, Kingsley

    2015-04-01

    Introduction In semi-arid areas such as northern Western Australia, wildfires are a natural part of the environment and many ecosystems in these landscapes have evolved and developed a strong relationship with fire. Soil microbial communities play a crucial role in ecosystem processes by regulating the cycling of nutrients via decomposition, mineralization, and immobilization processes. Thus, the structure (e.g. soil microbial biomass) and functioning (e.g. soil microbial activity) of microbial communities, as well as their changes after ecosystem disturbance, can be useful indicators of soil quality and health recovery. In this research, we assess the impacts of fire on soil microbial communities and their recovery in a biodiverse semi-arid environment of Western Australia (Pilbara region). New methods for determining soil microbial respiration as an indicator of microbial activity and soil health are also tested. Methodology Soil samples were collected from 10 similar ecosystems in the Pilbara with analogous native vegetation, but differing levels of post-fire disturbance (i.e. 3 months, 1 year, 5, 7 and 14 years after wildfire). Soil microbial activity was measured with the Solvita test which determines soil microbial respiration rate based on the measurement of the CO2 burst of a dry soil after it is moistened. Soils were dried and re-wetted and a CO2 probe was inserted before incubation at constant conditions of 25°C during 24 h. Measurements were taken with a digital mini spectrometer. Microbial (bacteria and fungi) biomass and community composition were measured by phospholipid fatty acid analysis (PLFA). Results Immediately after the fire (i.e. 3 months), soil microbial activity and microbial biomass are similar to 14 years 'undisturbed' levels (53.18±3.68 ppm CO2-CO and 14.07±0.65 mg kg-1, respectively). However, after the first year post-fire, with larger plant productivity, microbial biomass and microbial activity increase rapidly, peaking after 5

  11. VNIR-SWIR-TIR hyperspectral airborne campaign for soil and sediment mapping in semi-arid south african environments

    Science.gov (United States)

    Milewski, Robert; Chabrillat, Sabine; Eisele, Andreas

    2016-04-01

    Airborne hyperspectral remote sensing techniques has been proven to offer efficient procedures for soil and sediment mineralogical mapping in arid areas on larger scales. Optical methods based on traditional remote sensing windows using the solar reflective spectral wavelength range from the visible-near infrared (VNIR: 0.4-1.1 μm) to the short-wave infrared region (SWIR: 1.1-2.5 μm) allow mapping of common soil properties such as iron oxides, textural characteristics and organic carbon. However, soil mapping in semi-arid environments using VNIR-SWIR is currently limited due to specific spectral characteristics. Challenges appear in such environments due to the common presence of sandy soils (coarse textured) which grain size distribution is driven by the dominant mineral, quartz (SiO2), and which lacks any distinctive Si-O bond related spectral features within the VNIR-SWIR. Furthermore, another challenge is represented by the common presence of other specific spectral features due to different salts (gypsum, halite) or coatings of different forms (cyanobacteria, iron-oxides and/or -oxyhydroxides) for which few studies exists or that oft prevent detection of any other potential spectral feature of e.g. soil organics. In this context, more methodological developments are needed to overcome current limitations of hyperspectral remote sensing for arid areas, and to extent its scope using the thermal infrared (TIR) wavelength region within the atmospheric window between 8 and 14 μm (longwave infrared). In 2015 an extensive VNIR-SWIR-TIR airborne hyperspectral dataset consisting of HySpex-VNIR, HySpex-SWIR (NEO) and Hyper-Cam (TELOPS) data has been acquired in various Namibian and South African landscapes part of the Dimap/GFZ campaign in the frame of the BMBF-SPACES Geoarchive project. Research goals are 1) to demonstrate the capabilities to extract information from such a dataset and 2) to demonstrate the potential of advanced hyperspectral remote sensing

  12. Ammonia-oxidising bacteria not archaea dominate nitrification activity in semi-arid agricultural soil

    OpenAIRE

    Banning, Natasha C.; Maccarone, Linda D.; Fisk, Louise M.; Murphy, Daniel V.

    2015-01-01

    Ammonia-oxidising archaea (AOA) and bacteria (AOB) are responsible for the rate limiting step in nitrification; a key nitrogen (N) loss pathway in agricultural systems. Dominance of AOA relative to AOB in the amoA gene pool has been reported in many ecosystems, although their relative contributions to nitrification activity are less clear. Here we examined the distribution of AOA and AOB with depth in semi-arid agricultural soils in which soil organic matter content or pH had been altered, an...

  13. Comparison of groundwater recharge estimation methods for the semi-arid Nyamandhlovu area, Zimbabwe

    OpenAIRE

    Sibanda, T.; Nonner, J.C.; Uhlenbrook, S.

    2009-01-01

    The Nyamandhlovu aquifer is the main water resource in the semi-arid Umguza district in Matebeleland North Province in Zimbabwe. The rapid increase in water demand in the city of Bulawayo has prompted the need to quantify the available groundwater resources for sustainable utilization. Groundwater recharge estimation methods and results were compared: chloride mass balance method (19–62 mm/year); water-table fluctuation method (2–50 mm/year); Darcian flownet computations (16–28 mm/year); 14C ...

  14. A max-to-min technique for making projections of NDVI change in semi-arid Africa for food security early warning

    Science.gov (United States)

    Brown, M. E.; Funk, C. C.

    2005-12-01

    Climatic hazards such as droughts and floods often result in a decline in food production in economically vulnerable pre-industrial economies such as those in Africa. Early warning systems (EWS) have been developed to identify slow onset disasters such famine and epidemic disease that may result from hazardous environmental conditions. These conditions often precede food crises by many months, thus effective monitoring via satellite and in situ observations can allow for successful mitigation activities. Accurate forecasts of NDVI could increase monitoring lead times and allow for effective institutional planning of intervention, making early warning earlier. This paper presents a simple empirical max-to-min model for making 1 to 4 month NDVI projections. These statistical projections are based on parameterized satellite rainfall estimates (RFE) and relative humidity demand (RHD). A heuristic example in central Zimbabwe introduces the RFE growth and RHD loss terms. A quasi-global, one month ahead, 1 degree study then demonstrates reasonable accuracies in many semi-arid regions. In Africa, a 0.1 degree cross-validated skill assessment quantifies the technique's applicability at 1 to 4 month forecast intervals. These results suggest that useful projections can be made over many semi-arid, food insecure regions of Africa, with plausible extensions to drought prone areas of Asia, Australia and South America.

  15. Applicability of passive compost bioreactors for treatment of extremely acidic and saline waters in semi-arid climates.

    Science.gov (United States)

    Biermann, Vera; Lillicrap, Adam M; Magana, Claudia; Price, Barry; Bell, Richard W; Oldham, Carolyn E

    2014-05-15

    Extremely acidic and saline groundwater occurs naturally in south-western Australia. Discharge of this water to surface waters has increased following extensive clearing of native vegetation for agriculture and is likely to have negative environmental impacts. The use of passive treatment systems to manage the acidic discharge and its impacts is complicated by the region's semi-arid climate with hot dry summers and resulting periods of no flow. This study evaluates the performance of a pilot-scale compost bioreactor treating extremely acidic and saline drainage under semi-arid climatic conditions over a period of 2.5 years. The bioreactor's substrate consisted of municipal waste organics (MWO) mixed with 10 wt% recycled limestone. After the start-up phase the compost bioreactor raised the pH from ≤3.7 to ≥7 and produced net alkaline outflow for 126 days. The bioreactor removed up to 28 g/m(2)/d CaCO3 equivalent of acidity and acidity removal was found to be load dependent during the first and third year. Extended drying over summer combined with high salinity caused the formation of a salt-clay surface layer on top of the substrate, which was both beneficial and detrimental for bioreactor performance. The surface layer prevented the dehydration of the substrate and ensured it remained waterlogged when the water level in the bioreactor fell below the substrate surface in summer. However, when flow resumed the salt-clay layer acted as a barrier between the water and substrate decreasing performance efficiency. Performance increased again when the surface layer was broken up indicating that the negative climatic impacts can be managed. Based on substrate analysis after 1.5 years of operation, limestone dissolution was found to be the dominant acidity removal process contributing up to 78-91% of alkalinity generation, while bacterial sulfate reduction produced at least 9-22% of the total alkalinity. The substrate might last up to five years before the limestone

  16. 辽西半干旱区垄膜沟种方式对春玉米水分利用和产量的影响%Effect of Ridge Film Mulching Technique and Furrow Seeding of Spring Corn on Water Use and Yield in Semi-Arid Region in Liaoxi Area

    Institute of Scientific and Technical Information of China (English)

    肖继兵; 孙占祥; 蒋春光; 刘志; 郑家明; 冯良山

    2014-01-01

    order of increase of soil water storage in different treatments was T2>T1>CK>T3 after an effective rainfall. T1 and T2 enhanced water infiltration depth to 60㎝ in planting area compared with the control, which was 40 cm. The runoff efficiency was 61%and the rate of increase of soil moisture storage of T1 and T2 was 72%and 88%. The average of soil water of T1, T2, T3 and the control was 135.27 mm, 140.93 mm, 127.85 mm and 118.98 mm during growth stages of spring corn, increased by 13.69%, 18.45%and 7.46%, respectively, compared with the control. The yield of T1-T3 increased by 24.31%-32.58%, 9.95%-17.81%, 32.12%-37.16%, 16.58%-27.96%, 2.50%-9.40%, 10.85%-29.33%and 4.14%-17.95%in 2007-2013, the average production of T1, T2 and T3 increased by 14.52%, 20.01%and 23.44%compared with the control. The water use efficiency of T1-T3 increased by 24.66%-36.07%, 14.12%-23.73%, 38.34%-53.89%, 29.07%-35.68%, 1.20%-19.60%and 9.02%-32.55%, the average of water use efficiency of T1, T2 and T3 increased by 20.39%, 27.94%and 28.02%compared with the control. It was also found that the effect of increase of yield and water use efficiency was significant under lower rainfall.[Conclusion] The effect of Micro-rainwater-collecting planting mode by ridge film mulching and furrow seeding in dry farmland on rainwater harvesting, water storage and soil moisture conservation was definite after 7 years of study in semi-arid region in Liaoxi area. The technique could mitigate the negative impact of drought on spring sowing and seedlings growth in spring and enrich the theoretical basis of the rain-harvesting agriculture of dry farming in the area. By application and dissemination of the technique, it could improve rainfall resources utilization and water use efficiency and promote stable and high yield of spring corn and healthy and sustainable development of dry farming in the area. The study will provide important references for development of the rain-harvesting agriculture of dry farming in the

  17. The Brazilian semi-arid environment influences the physiological responses of goats

    Directory of Open Access Journals (Sweden)

    Laylson da Silva Borges

    2015-12-01

    Full Text Available In this review, we compile information about the physiologic responses of goats to north-eastern Brazil’s semiarid environment and suggest some strategies to avoid the thermal discomfort of these small ruminants. Due to recent weather changes, the number of studies seeking to improve animal welfare has intensified to minimize the economic losses on animal production in the tropics. Among the climatic variables, the high room temperature, air humidity, and direct solar radiation are the main causes of physiological discomfort in animals that decrease their productivity. Therefore, it is very important to study the components that interact in the thermoregulation process, the consequences of disequilibrium in this process, and ways to ease these effects, aiming to provide thermal comfort to and seek the animal welfare of the animals. Therefore, it is essential to know the interaction between animals and the environment and the adaptability of the species and breeds that are exploited to make decisions about farming systems and management strategies to maximize productivity.

  18. Impact of climate and analysis of desertification processes in semi arid land in Algeria: using data of Alsat-1 and Landsat

    Science.gov (United States)

    Ahmed, Z.; Habib, M.; Sid Ali, H.; Sofiane, K.

    2015-04-01

    The degradation of natural resources in arid and semi-arid areas was highlighted dramatically during this century due to population growth and transformation of land use systems. The Algerian steppe has undergone a regression over the past decade due to drought cycle, the extension of areas cultivated in marginal lands, population growth and overgrazing. These phenomena have led to different degradation processes, such as the destruction of vegetation, soil erosion, and deterioration of the physical environment. In this study, the work is mainly based on the criteria for classification and identification of physical parameters for spatial analysis, and multi-sources factors to determine the vulnerability of steppe formations and their impact on desertification. To do this, we used satellite data Alsat-1 (2009) IRS (2009) and LANDSAT TM (2001). These cross-sectional data with exogenous information could monitor the impact of the semi arid ecological diversity of steppe formations. A hierarchical process including the supervised image classification was used to characterize the main steppe formations. An analysis of the vulnerability of plant was conducted to assign weights and identify areas most susceptible to desertification. Vegetation indices combined with classification are used to characterize the forest and steppe formations to determine changes in land use. The results of this present study provide maps of different components of the steppe, formation that could assist in highlighting the magnitude of the degradation pathways, which affects the steppe environment, allowing an analysis of the process of desertification in the region.

  19. On the potential for regolith control of fluvial terrace formation in semi-arid escarpments

    Science.gov (United States)

    Norton, K. P.; Schlunegger, F.; Litty, C.

    2016-02-01

    Cut-fill terraces occur throughout the western Andes, where they have been associated with pluvial episodes on the Altiplano. The mechanism relating increased rainfall to sedimentation is, however, not well understood. Here, we apply a hillslope sediment model and reported cosmogenic nuclide concentrations in terraces to examine terrace formation in semi-arid escarpment environments. We focus on the Pisco river system in western Peru in order to determine probable hillslope processes and sediment transport conditions during phases of terrace formation. Specifically, we model steady-state and transient hillslope responses to increased precipitation rates. The measured terrace distribution and sediment agree with the transient predictions, suggesting strong climatic control on the cut-fill sequences in western Peru primarily through large variations in sediment load. Our model suggests that the ultimate control for these terraces is the availability of sediment on the hillslopes, with hillslope stripping supplying large sediment loads early in wet periods. At the Pisco river, this is manifest as an approximately 4-fold increase in erosion rates during pluvial periods. We suggest that this mechanism may also control terrace occurrence other semi-arid escarpment settings.

  20. Climate change mitigation by carbon stock - the case of semi-arid West Africa

    Science.gov (United States)

    Lykke, A. M.; Barfod, A. S.; Tinggaard Svendsen, G.; Greve, M.; Svenning, J.-C.

    2009-11-01

    Semi-arid West Africa has not been integrated into the afforestation/reforestation (AR) carbon market. Most projects implemented under the Clean Development Mechanism (CDM) have focused on carbon emission reductions from industry and energy consumption, whereas only few (only one in West Africa) have been certified for AR carbon sequestration. A proposed mechanism, Reducing Emissions from Deforestation and Degradation (REDD) to be discussed under COP15 aims to reduce emissions by conserving already existing forests. REDD has high potential for carbon stocking at low costs, but focuses primarily on rain forest countries and excludes semi-arid West Africa from the preliminary setup. African savannas have potential to store carbon in the present situation with degrading ecosystems and relatively low revenues from crops and cattle, especially if it is possible to combine carbon stocking with promotion of secondary crops such as food resources and traditional medicines harvested on a sustainable basis. Methods for modelling and mapping of potential carbon biomass are being developed, but are still in a preliminary state. Although economic benefits from the sale of carbon credits are likely to be limited, carbon stocking is an interesting option if additional benefits are considered such as improved food security and protection of biodiversity.

  1. Ammonia-oxidising bacteria not archaea dominate nitrification activity in semi-arid agricultural soil

    Science.gov (United States)

    Banning, Natasha C.; Maccarone, Linda D.; Fisk, Louise M.; Murphy, Daniel V.

    2015-06-01

    Ammonia-oxidising archaea (AOA) and bacteria (AOB) are responsible for the rate limiting step in nitrification; a key nitrogen (N) loss pathway in agricultural systems. Dominance of AOA relative to AOB in the amoA gene pool has been reported in many ecosystems, although their relative contributions to nitrification activity are less clear. Here we examined the distribution of AOA and AOB with depth in semi-arid agricultural soils in which soil organic matter content or pH had been altered, and related their distribution to gross nitrification rates. Soil depth had a significant effect on gene abundances, irrespective of management history. Contrary to reports of AOA dominance in soils elsewhere, AOA gene copy numbers were four-fold lower than AOB in the surface (0-10 cm). AOA gene abundance increased with depth while AOB decreased, and sub-soil abundances were approximately equal (10-90 cm). The depth profile of total archaea did not mirror that of AOA, indicating the likely presence of archaea without nitrification capacity in the surface. Gross nitrification rates declined significantly with depth and were positively correlated to AOB but negatively correlated to AOA gene abundances. We conclude that AOB are most likely responsible for regulating nitrification in these semi-arid soils.

  2. Balanço hídrico em solo com cultivos de subsistência no semi-árido do nordeste do Brasil Water budget in a soil with food crops in the semi-arid region of northeast Brazil

    Directory of Open Access Journals (Sweden)

    Antonio Celso Dantas Antonino

    2000-04-01

    Full Text Available Tendo em vista ser a água limitante e haver poucos estudos sobre o balanço hídrico em cultivos do semi-árido nordestino, instalou-se um experimento em Coxixola, PB, com quatro tratamentos (plantios de milho e de feijão, solo nu e com cobertura morta, parcelas de 7,7 x 10 m e espaçamento de plantio de 1,1 x 1,0 m. Foram medidos chuva, evaporação (Tanque "classe A" e armazenamento de água no solo (sonda de nêutrons. A chuva pouca (212 mm e mal distribuída causou restrição hídrica na parte final do experimento e foi responsável pelas baixas eficiências de uso de água e baixas produtividades do milho (grãos e biomassa total, 282 e 1141 kg ha-1 e do feijão (166 e 558 kg ha-1. Solo nu e com cobertura morta tiveram comportamento semelhante, com grandes perdas de água (1,57 e 1,48 mm dia-1, respectivamente e apenas pequenos aumentos nas lâminas armazenadas no perfil do solo, ao final do experimento (28 e 35 mm, respectivamente. O pequeno aumento e a dificuldade de obtenção de resíduos vegetais fazem com que esta cobertura morta não seja prática promissora na região.Considering that water is a limiting factor and there are few studies on water balance in the semi-arid Northeastern Brazil, an experiment was established at Coxixola, PB, Brazil, with four treatments (corn and beans crops, bare soil and soil covered with mulch, in plots of 7.7 x 10 m and plant spacing of 1.1 x 1.0 m. Rainfall, evaporation (Class A tank and soil water (neutron probe were monitored. Low (212 mm and irregular rainfall resulted in water deficit towards the final period of the experiment and was responsible for the low water use efficiencies and low productivity of corn (grain and total biomass, 282 and 1141 kg ha-1 and beans (166 and 558 kg ha-1. Bare soil and mulch had similar results, with high water losses, 1.57 and 1.48 mm day-1, respectively, and only small increases in stored soil water (28 and 35 mm, respectively were observed at the end of

  3. Fertilizer induced nitrous oxide emissions from Vertisols and Alfisols during sweet sorghum cultivation in the Indian semi-arid tropics.

    Science.gov (United States)

    Ramu, Karri; Watanabe, Takeshi; Uchino, Hiroshi; Sahrawat, Kanwar L; Wani, Suhas P; Ito, Osamu

    2012-11-01

    Nitrous oxide (N(2)O) emissions from Vertisols and Alfisols during sweet sorghum cultivation in the Indian semi-arid tropics were determined using a closed chamber technique during the rainy season (June-October) of 2010. The study included two treatments, nitrogen (N) at a rate of 90 kg/ha and a control without N fertilizer application. The N(2)O emissions strongly coincided with N fertilization and rainfall events. The cumulative N(2)O-N emission from Alfisols was 1.81 N(2)O-N kg/ha for 90 N treatment and 0.15 N(2)O-N kg/ha for the 0 N treatment. Similarly, the N(2)O-N emission from Vertisols was 0.70 N(2)O-N kg/ha for 90 N treatment and 0.09 N(2)O-N kg/ha for the 0 N treatment. The mean N(2)O-N emission factor for fertilizer induced emissions from the Alfisols was 0.90% as compared to 0.32% for Vertisols. Our results suggest that the N(2)O emissions are dependent on the soil properties. Therefore, the monitoring of N(2)O emissions from different agro-ecological regions, having different soil types, rainfall characteristics, cropping systems and crop management practices are necessary to develop comprehensive and accurate green house gas inventories. PMID:22967492

  4. Vulnerability and policy relevance to drought in the semi-arid tropics of Asia – A retrospective analysis

    Directory of Open Access Journals (Sweden)

    Naveen P. Singh

    2014-06-01

    Full Text Available Of all the natural hazards, drought affects the maximum number of people globally causing devastating impacts. It is a reality that drought results in sets of socio-economic impacts starting with crop-yield failure, unemployment, erosion of assets, income decrease, poor nutrition and decreasing risk absorptive capacity, thereby increasing the vulnerability of the community. This paper gives a brief of the existing approaches that focus on vulnerability and impact assessment aid to characterize and identify regions, sectors and communities which are at risk for drought currently and in the future. It also discusses the limitation, constraints and pre-requisites in these approaches and highlights the importance of micro-level information to have a more realistic understanding of impact and vulnerability through illustration, with reference to the recent study conducted by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT. This exercise will provide a guiding framework for devising action plans to improve adaptive capacity among vulnerable populations.

  5. Fertilizer induced nitrous oxide emissions from Vertisols and Alfisols during sweet sorghum cultivation in the Indian semi-arid tropics.

    Science.gov (United States)

    Ramu, Karri; Watanabe, Takeshi; Uchino, Hiroshi; Sahrawat, Kanwar L; Wani, Suhas P; Ito, Osamu

    2012-11-01

    Nitrous oxide (N(2)O) emissions from Vertisols and Alfisols during sweet sorghum cultivation in the Indian semi-arid tropics were determined using a closed chamber technique during the rainy season (June-October) of 2010. The study included two treatments, nitrogen (N) at a rate of 90 kg/ha and a control without N fertilizer application. The N(2)O emissions strongly coincided with N fertilization and rainfall events. The cumulative N(2)O-N emission from Alfisols was 1.81 N(2)O-N kg/ha for 90 N treatment and 0.15 N(2)O-N kg/ha for the 0 N treatment. Similarly, the N(2)O-N emission from Vertisols was 0.70 N(2)O-N kg/ha for 90 N treatment and 0.09 N(2)O-N kg/ha for the 0 N treatment. The mean N(2)O-N emission factor for fertilizer induced emissions from the Alfisols was 0.90% as compared to 0.32% for Vertisols. Our results suggest that the N(2)O emissions are dependent on the soil properties. Therefore, the monitoring of N(2)O emissions from different agro-ecological regions, having different soil types, rainfall characteristics, cropping systems and crop management practices are necessary to develop comprehensive and accurate green house gas inventories.

  6. Safe greywater reuse to augment water supply and provide sanitation in semi-arid areas of rural India.

    Science.gov (United States)

    Godfrey, S; Labhasetwar, P; Wate, S; Jimenez, B

    2010-01-01

    Water reuse is recognized as a tool to increase water supply in peri-urban areas of semi-arid and arid regions of the world. However, it is an option rarely explored for rural areas in developing countries, and has not been documented extensively in the scientific literature. This paper presents results from 6 greywater reuse systems which were built with the objective to augment water supply and to provide sanitation in rural low income areas of Madhya Pradesh, India. The systems are based on reclaiming greywater from bathing for the use in toilet flushing and kitchen garden irrigation. The reuse systems were implemented based on the scientific rationale presented in the WHO (2006) guidelines. The paper presents evidence from the operation and evaluation of the greywater treatment plants under field conditions between 2005 and 2008. The paper concludes that greywater is a highly cost effective solution for water scarcity. In this study, reusing greywater resulted in a 60% increase in water availability, a reduction in open defecation and a fourfold increase in food availability.

  7. Mapping Soil hydrologic features in a semi-arid irrigated area in Spain

    Science.gov (United States)

    Jiménez-Aguirre, M.° Teresa; Isidoro, Daniel; Usón, Asunción

    2016-04-01

    The lack of soil information is a managerial problem in irrigated areas in Spain. The Violada Irrigation District (VID; 5234 ha) is a gypsic, semi-arid region in the Middle Ebro River Basin, northeast Spain. VID is under irrigation since the 1940's. The implementation of the flood irrigation system gave rise to waterlogging problems, solved along the years with the installation of an artificial drainage network. Aggregated water balances have been performed in VID since the early 1980's considering average soil properties and aggregated irrigation data for the calculations (crop evapotranspiration, canal seepage, and soil drainage). In 2008-2009, 91% of the VID was modernized to sprinkler irrigation. This new system provides detailed irrigation management information that together with detailed soil information would allow for disaggregated water balances for a better understanding of the system. Our goal was to draw a semi-detailed soil map of VID presenting the main soil characteristics related to irrigation management. A second step of the work was to set up pedotransfer functions (PTF) to estimate the water content and saturated hydraulic conductivity (Ks) from easily measurable parameters. Thirty four pits were opened, described and sampled for chemical and physical properties. Thirty three additional auger holes were sampled for water holding capacity (WHC; down to 60 cm), helping to draw the soil units boundaries. And 15 Ks tests (inverse auger hole method) were made. The WHC was determined as the difference between the field capacity (FC) and wilting point (WP) measured in samples dried at 40°C during 5 days. The comparison with old values dried at 105°C for 2 days highlighted the importance of the method when gypsum is present in order to avoid water removal from gypsum molecules. The soil map was drawn down to family level. Thirteen soil units were defined by the combination of five subgroups [Typic Calcixerept (A), Petrocalcic Calcixerept (B), Gypsic

  8. A 500-year history of floods in the semi arid basins of south-eastern Spain

    Science.gov (United States)

    Sánchez García, Carlos; Schulte, Lothar; Peña, Juan Carlos; Carvalho, Filpe; Brembilla, Carla

    2016-04-01

    Floods are one of the natural hazards with higher incidence in the south-eastern Spain, the driest region in Europe, causing fatalities, damage of infrastructure and economic losses. Flash-floods in semi arid environments are related to intensive rainfall which can last from few hours to days. These floods are violent and destructive because of their high discharges, sediment transport and aggradation processes in the flood plain. Also during historical times floods affected the population in the south-eastern Spain causing sever damage or in some cases the complete destruction of towns. Our studies focus on the flood reconstruction from historical sources of the Almanzora, Aguas and Antas river basins, which have a surface between 260-2600 km2. We have also compiled information from the Andarax river and compared the flood series with the Guadalentín and Segura basins from previous studies (Benito et. al., 2010 y Machado et al., 2011). Flood intensities have been classified in four levels according to the type of damage: 1) ordinary floods that only affect agriculture plots; 2) extraordinary floods which produce some damage to buildings and hydraulic infrastructure; 3) catastrophic floods which caused sever damage, fatalities and partial or complete destruction of towns. A higher damage intensity of +1 magnitude was assigned when the event is recorded from more than one major sub-basin (stretches and tributaries such as Huércal-Overa basin) or catchment (e.g. Antas River). In total 102 incidences of damages and 89 floods were reconstructed in the Almanzora (2.611 km2), Aguas (539 km2), Antas (261 km2) and Andarax (2.100 km2) catchments. The Almanzora River was affected by 36 floods (1550-2012). The highest events for the Almanzora River were in 1580, 1879, 1973 and 2012 producing many fatalities and destruction of several towns. In addition, we identified four flood-clusters 1750-1780, 1870-1900, 1960-1977 and 1989-2012 which coincides with the periods of

  9. Deriving seasonal dynamics in ecosystem properties of semi-arid savanna grasslands from in situ-based hyperspectral reflectance

    DEFF Research Database (Denmark)

    Tagesson, Håkan Torbern; Fensholt, Rasmus; Huber, S.;

    2015-01-01

    This paper investigates how hyperspectral reflectance (between 350 and 1800 nm) can be used to infer ecosystem properties for a semi-arid savanna grassland in West Africa using a unique in situ-based multi-angular data set of hemispherical conical reflectance factor (HCRF) measurements. Relations......This paper investigates how hyperspectral reflectance (between 350 and 1800 nm) can be used to infer ecosystem properties for a semi-arid savanna grassland in West Africa using a unique in situ-based multi-angular data set of hemispherical conical reflectance factor (HCRF) measurements...

  10. 半干旱区气候变化背景下近20年内蒙古武川县耕地质量变化%Cultivated land quality change of Wuchuan county in Inner Mongolia under background of climate change in semi-arid regions during recent 20 years

    Institute of Scientific and Technical Information of China (English)

    王立为; 安萍莉; 潘志华; 赫迪; 董智强

    2013-01-01

    Cultivated land quality is a key factor of national economic and social sustainable development. The change of cultivated land quality with climate change has become one of the hot research areas in global change in recent years. Based on the meteorological data, soil information and field experimental data were used, utilizing the Wageninngen method recommended by the Food and Agriculture Organization (FAO) to calculate the potential productivity of potato and spring wheat from 1989 to 2009 in Wuchuan County, Inner Mongolia, a typical semi-arid climate-sensitive area in North China. We examined the influence of climate change on production potential, the standard cropping system, and the yield. Further, by the method of regulations of Farmland classification, we used the data of potential productivity and land use to analyze the changes of natural quality grades and utilization grades under climate change. The results showed that:(1) The annual temperature of Wuchuan County increased at an average rate of 0.57℃/10a during 1967-2009. The precipitation varied greatly among the years, and the annual precipitation declined slightly over time. The soil relative humidity in soil layers 0-10 cm and 10-20 cm depth in crop growing season (April-September) in the period 1989-2009 had a decreasing trend with an average rate of 1.8%/a and 1.5%/a, respectively. Drought index increased noticeably. In conclusion, Wuchuan County was getting warmer and dryer under climate change. (2) Most of the cultivated lands were the dry lands in Wuchuan county (accounting for more than 90%), but the irrigated lands increased in recent years. The main crop in Wuchuan county was potatoes in 2009 instead of spring wheat in 1989. The planting area of potatoes increased from 8.4%to 39.8%, while spring wheat planting area decreasing from 52.1%to 17.1%in the period 1989-2009. (3) The production potential of the potatoes and spring wheat showed a declining trend under the dry warming climate in

  11. Burning crop residues under no-till in semi-arid land, Northern Spain - effects on soil organic matter, aggregation, and earthwor populations.

    NARCIS (Netherlands)

    Virto, I.; Imaz, M.J.; Enrique, A.; Hoogmoed, W.B.; Bescansa, P.

    2007-01-01

    Stubble burning has traditionally been used in semi-arid land for pest and weed control, and to remove the excess of crop residues before seeding in no-tillage systems. We compared differences in soil properties in a long-term (10 years) tillage trial on a carbonated soil in semi-arid north-east Spa

  12. Semi-arid savanna of the Potlake Nature Reserve and surrounding areas in Sekhukhuneland, South Africa

    Directory of Open Access Journals (Sweden)

    S.J. Siebert

    2003-12-01

    Full Text Available A hierarchical classification, description, and ecological and floristic interpretations are presented on the vegetation types of the semi-arid northern savanna of the Sekhukhuneland Centre of Plant Endemism. Relevés were compiled in 47 stratified random plots. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed eight plant communities, classified as four associations, one of which is subdivided into five sub-associations. For each plant community, the floristic richness, endemism and conservation status was determined. Much of the plant community distribution can be ascribed to environmental factors and anthropogenic disturbance. An ordination (DECORANA, based on floristic data, showed environmental gradients that possibly exist between plant communities and associated habitats. The floristic information, proposed classification, general description and vegetation key, can be used for the identification and monitoring of protected areas, land-use planning, and further conservation research.

  13. IMPACT OF ZOOTECHNICAL PARAMETERS ON CELL QUALITY OF CATTLE MILK (SEMI-ARID COSTAL TUNISIA

    Directory of Open Access Journals (Sweden)

    R. HAJ MBAREK

    2015-09-01

    Full Text Available The work was realized on a sample of 50 cattle herds, conducted in aboveground, in a coastal area of the semi-arid Tunisia, by using investigation related to cows and their breeding and milking conditions as well as despoliation in milk control data. Analysis of the data relating to the parameters of udder conformation and cow cleanliness revealed that “Udder depth” settings “Udder cleanliness” have been shown to affect the ICC and are considered factors risk of bovine mastitis. The study of breeding and milking conditions highlight some significant factors on changes on the variation of cell counts and the probability of the spread of mastitis, especially the "No disinfection of teat." The level of housing, the analysis revealed that the use of a litter reduced to half the average of ICC which proved highly related to the cleanliness of both the sleeping area as the udder.

  14. The causes of stemflow variation in three semi-arid growing species of northeastern Mexico

    Science.gov (United States)

    Návar, José

    1993-05-01

    This study was conducted to determine the role of some plant parameters on stemflow generation. Stemflow measurements in individual shrubs of three semi-arid growing species ( Diospyrus texana, Acacia farnesiana and Prosopis laevigata) were carried out under natural and simulated rainfall conditions in northeastern Mexico. Stemflow coefficients for individual shrubs were developed. The analysis of variance showed a significant difference among the species for both natural and simulated rainfall conditions. The multiple linear models suggested that the number of branches and position on the canopy, instead of total projected branch area, controls stemflow. There were also suggestions that bark roughness, leaf and twig position may also explain some of the interspecific stemflow variation. This contribution was suggested by an introduced funnelling ratio.

  15. Dependence of juvenile reef fishes on semi-arid hypersaline estuary microhabitats as nurseries.

    Science.gov (United States)

    Sales, N S; Dias, T L P; Baeta, A; Pessanha, A L M

    2016-07-01

    The differences between fish assemblages in three microhabitat types, in relation to vegetation and sediment characteristics of a hypersaline estuary located in an semi-arid zone in north-eastern Brazil, were investigated. Fishes were collected using a beach seine during the rainy and dry seasons in 2012. A total of 78 species were recorded, with the most common families being Gerreidae, Lutjanidae and Tetraodontidae. The majority of species were represented by juveniles, with Eucinostomus argenteus, Ulaema lefroyi and Sphoeroides greeleyi being the dominant species. The fish assemblage structures differed significantly among microhabitat types, with the narrow intertidal flat adjacent to the mangrove fringe supporting the most diverse fish fauna. In addition, only 27 species were common to all of the microhabitats. The results support the hypothesis that hypersaline estuaries serve as important nursery areas for various reef fish species, due to the structural complexity provided by their macroalgae beds and mangroves.

  16. Demographic noise and resilience in a semi-arid ecosystem model

    CERN Document Server

    Realpe-Gomez, John; Galla, Tobias; McKane, Alan J; Rietkerk, Max

    2013-01-01

    The scarcity of water characterizing drylands forces vegetation to adopt appropriate survival strategies. Some of these generate water-vegetation feedback mechanisms that can lead to spatial self-organisation of vegetation. To date these phenomena have mostly been studied with models representing plants by a density of biomass, varying continuously in time and space. Such models disregard the discrete nature of plant individuals and their intrinsically stochastic behaviour. These features give rise to demographic noise, which can influence the qualitative dynamics of ecosystem models. In the present work we explore the effects of demographic noise on the resilience of a model semi-arid ecosystem. We introduce a spatial stochastic eco-hydrological hybrid model in which plants are modelled as discrete entities subject to stochastic dynamical rules, while the dynamics of surface and soil water are described by continuous variables. The model has a deterministic approximation very similar to previous continuous m...

  17. Climate change in semi-arid Malawi: Perceptions, adaptation strategies and water governance

    Directory of Open Access Journals (Sweden)

    Miriam K. Joshua

    2016-03-01

    Full Text Available Climate change and variability are a threat to sustainable agricultural production in semi-arid areas of Malawi. Overdependence on subsistence rain-fed agriculture in these areas calls for the identification of sustainable adaptation strategies. A study was therefore conducted in Chikwawa, a semi-arid district in southern Malawi, to: (1 assess community’s perception of a changing climate against empirical evidence, (2 determine their local adaptive measures, (3 evaluate the potential of irrigated agriculture as an adaptive measure in household food security and (4 challenges over access to available water resources. The study employed focus group discussions and key informant interviews to assess people’s perceptions of climate change and variability and their desired interventions. To validate the people’s perceptions, rainfall and temperature data for the period 1960–2010 were analysed. A participatory complete randomised experimental design in both rain-fed and dry season–irrigated conditions was conducted to assess a maize cropping system that would improve adaptation. The study established persistent declining yields from rain-fed production in part because of perennial rainfall failure. In response, the community has shifted its focus to irrigation as an adaptation strategy, which has in turn triggered water conflicts in the community over the control of the resource. Water legislation however fails to adequately provide for rules governing sharing of water resources between various stakeholders. This article therefore recommends development of an appropriate institutional framework that forms a strong basis for equitable distribution of water for irrigation in areas most vulnerable to extreme climate events – including droughts and floods.Keywords: Food Security; Climate Change and Variability; Rainfall Variability; Irrigation; Water Resources; Governance Crisis

  18. Strategies to reducing GHG emissions in semi-arid rangelands of Mexico

    Directory of Open Access Journals (Sweden)

    Heriberto Díaz Solís

    2016-03-01

    Full Text Available SESS (Simple Ecological Sustainability Simulator model was modified to evaluate 3 management strategies that could increase CO2 sequestration and reduce methane emissions in cow-calf production systems in semi-arid rangelands. The management strategies included (1 maintenance of a high and constant stocking rate (CONTROL, which is the most common current practice, (2 maintenance of a low and constant stocking rate (LOW SR and (3 adjustment of stocking rate before the beginning of each breeding season based on the amount of precipitation during the previous growing season (REPLA-PPT. The model was parameterized to represent a typical extensive (5 000 ha cow-calf production system in the northeastern portion of the Mexican state of Coahuila under an historical (1950 to 1994 precipitation regime, and compared carbon sequestration, methane emissions, animal performance and net profit resulting from each strategy. Results of the 45-year simulations indicated the REPLA-PPT stocking rate strategy had the greatest improvement of range condition, captured more CO2 in vegetation, had the lowest methane emissions, substantially improved mean body condition score and reduced annual mortality of cattle, compared to the constant stocking rate strategies. REPLA-PPT also showed the highest values for calves weaned, and kg weaned per ton of methane produced and highest long-term net profit. This suggests that adaptive management of extensive cow-calf production systems in semi-arid environments could increase carbon sequestration in soils and reduce methane emissions, while improving range production, maintaining animal production and giving the greatest long-term net profit.

  19. Contribution of semi-arid ecosystems to interannual variability of the global carbon cycle.

    Science.gov (United States)

    Poulter, Benjamin; Frank, David; Ciais, Philippe; Myneni, Ranga B; Andela, Niels; Bi, Jian; Broquet, Gregoire; Canadell, Josep G; Chevallier, Frederic; Liu, Yi Y; Running, Steven W; Sitch, Stephen; van der Werf, Guido R

    2014-05-29

    The land and ocean act as a sink for fossil-fuel emissions, thereby slowing the rise of atmospheric carbon dioxide concentrations. Although the uptake of carbon by oceanic and terrestrial processes has kept pace with accelerating carbon dioxide emissions until now, atmospheric carbon dioxide concentrations exhibit a large variability on interannual timescales, considered to be driven primarily by terrestrial ecosystem processes dominated by tropical rainforests. We use a terrestrial biogeochemical model, atmospheric carbon dioxide inversion and global carbon budget accounting methods to investigate the evolution of the terrestrial carbon sink over the past 30 years, with a focus on the underlying mechanisms responsible for the exceptionally large land carbon sink reported in 2011 (ref. 2). Here we show that our three terrestrial carbon sink estimates are in good agreement and support the finding of a 2011 record land carbon sink. Surprisingly, we find that the global carbon sink anomaly was driven by growth of semi-arid vegetation in the Southern Hemisphere, with almost 60 per cent of carbon uptake attributed to Australian ecosystems, where prevalent La Niña conditions caused up to six consecutive seasons of increased precipitation. In addition, since 1981, a six per cent expansion of vegetation cover over Australia was associated with a fourfold increase in the sensitivity of continental net carbon uptake to precipitation. Our findings suggest that the higher turnover rates of carbon pools in semi-arid biomes are an increasingly important driver of global carbon cycle inter-annual variability and that tropical rainforests may become less relevant drivers in the future. More research is needed to identify to what extent the carbon stocks accumulated during wet years are vulnerable to rapid decomposition or loss through fire in subsequent years.

  20. The importance of plant water use on evapotranspiration covers in semi-arid Australia

    Science.gov (United States)

    Schneider, A.; Arnold, S.; Doley, D.; Mulligan, D. R.; Baumgartl, T.

    2012-10-01

    We estimated the evapotranspiration (ET) for an area vegetated with characteristic semi-arid native Australian plant species on ET mine waste cover systems. These systems aim to minimise drainage into underlying hazardous wastes by maximising evaporation (E) from the soil surface and transpiration from vegetation. An open top chamber was used to measure diurnal and daily ET of two plant species - Senna artemisioides (silver cassia) and Sclerolaena birchii (galvanised burr) - after a simulated rainfall event, as well as E from bare soil. Both ET and E decreased with increasing time after initial watering. Different temporal patterns were observed for daily ET from the two plant species and E from bare soil, revealing Senna artemisioides as intensive and Sclerolaena birchii as extensive water exploiters. A strong positive linear relationship was identified between ET (and E), and the atmospheric water demand represented by the vapour pressure deficit. The relationship always was more pronounced in the morning than in the afternoon, indicating a diminishing water supply from the soil associated with a declining unsaturated hydraulic conductivity of the soil in the afternoon. The slopes of the regression lines were steepest for Senna artemisioides, reflecting its intensive water-exploiting characteristics. We used the derived estimates of ET and E to predict the effect of species composition on plot ET in relation to total vegetation coverage. Although both species proved suitable for an operational ET cover system, vegetation coverage should exceed at least 50% in order to markedly influence plot ET, a value which is likely to be unsustainable in semi-arid climates.

  1. The importance of plant water use on evapotranspiration covers in semi-arid Australia

    Directory of Open Access Journals (Sweden)

    A. Schneider

    2012-10-01

    Full Text Available We estimated the evapotranspiration (ET for an area vegetated with characteristic semi-arid native Australian plant species on ET mine waste cover systems. These systems aim to minimise drainage into underlying hazardous wastes by maximising evaporation (E from the soil surface and transpiration from vegetation. An open top chamber was used to measure diurnal and daily ET of two plant species – Senna artemisioides (silver cassia and Sclerolaena birchii (galvanised burr – after a simulated rainfall event, as well as E from bare soil. Both ET and E decreased with increasing time after initial watering. Different temporal patterns were observed for daily ET from the two plant species and E from bare soil, revealing Senna artemisioides as intensive and Sclerolaena birchii as extensive water exploiters. A strong positive linear relationship was identified between ET (and E, and the atmospheric water demand represented by the vapour pressure deficit. The relationship always was more pronounced in the morning than in the afternoon, indicating a diminishing water supply from the soil associated with a declining unsaturated hydraulic conductivity of the soil in the afternoon. The slopes of the regression lines were steepest for Senna artemisioides, reflecting its intensive water-exploiting characteristics. We used the derived estimates of ET and E to predict the effect of species composition on plot ET in relation to total vegetation coverage. Although both species proved suitable for an operational ET cover system, vegetation coverage should exceed at least 50% in order to markedly influence plot ET, a value which is likely to be unsustainable in semi-arid climates.

  2. Impact of debris dams on hyporheic interaction along a semi-arid stream

    Science.gov (United States)

    Lautz, Laura K.; Siegel, Donald I.; Bauer, Robert L.

    2006-01-01

    Hyporheic exchange increases the potential for solute retention in streams by slowing downstream transport and increasing solute contact with the substrate. Hyporheic exchange may be a major mechanism to remove nutrients in semi-arid watersheds, where livestock have damaged stream riparian zones and contributed nutrients to stream channels. Debris dams, such as beaver dams and anthropogenic log dams, may increase hyporheic interactions by slowing stream water velocity, increasing flow complexity and diverting water to the subsurface.Here, we report the results of chloride tracer injection experiments done to evaluate hyporheic interaction along a 320 m reach of Red Canyon Creek, a second order stream in the semi-arid Wind River Range of Wyoming. The study site is part of a rangeland watershed managed by The Nature Conservancy of Wyoming, and used as a hydrologic field site by the University of Missouri Branson Geologic Field Station. The creek reach we investigated has debris dams and tight meanders that hypothetically should enhance hyporheic interaction. Breakthrough curves of chloride measured during the field experiment were modelled with OTIS-P, a one-dimensional, surface-water, solute-transport model from which we extracted the storage exchange rate and cross-sectional area of the storage zone As for hyporheic exchange. Along gaining reaches of the stream reach, short-term hyporheic interactions associated with debris dams were comparable to those associated with severe meanders. In contrast, along the non-gaining reach, stream water was diverted to the subsurface by debris dams and captured by large-scale near-stream flow paths. Overall, hyporheic exchange rates along Red Canyon Creek during snowmelt recession equal or exceed exchange rates observed during baseflow at other streams.

  3. Effect of Supplemental Irrigation on Lentil Yield and Growth in Semi-Arid Environment

    Directory of Open Access Journals (Sweden)

    Abdullah KAHRAMAN

    2016-06-01

    Full Text Available Lentil is one of the most promising legume crops providing nutritional and food assurance to human beings. Due to extensive production of lentil crop in rain-fed agriculture system, its growth and yield are mainly determined by the levels of precipitation. Consequently, it usually faces drought stress during the generative stage resulting in low yield. In such scenario, controlled supplemental irrigation (SI can improve and stabilize the productivity. Therefore, the present study was conducted to determine the effect of supplemental irrigation on the growth and yield of lentil crop under semi-arid climate conditions of Turkey. An experiment was performed during two consecutive crop seasons at Sanliurfa, Turkey with annual mean rainfall of 196 and 275 mm in the first and second experimental year, respectively. Six supplementary irrigation treatments were given using drip irrigation system [no supplement irrigation (I0, 25% (I25, 50% (I50, 75% (I75, 100% (I100, full irrigation and 125% (I125 supplement irrigation depending on the available soil water content]. Results obtained in the study indicated that in both study years, highest biomass, harvest index and grain yield values were obtained from fully irrigated treatments (I100, while non-supplementary irrigated treatments have provided lowest values. It should be clearly noticed that growth parameters including yield were lower under over-irrigation treatment (I125. Hence, it is recommended that farmers need to optimize the supplemental irrigation technique to obtain desired yields. This study will support the successful usage of the supplemental irrigation technology to improve lentil productivity, particularly under semi-arid environment.

  4. Productivity and residual benefits of grain legumes to sorghum under semi-arid conditions in southwestern Zimbabwe

    NARCIS (Netherlands)

    Ncube, B.; Twomlow, S.J.; Wijk, van M.T.; Dimes, J.P.; Giller, K.E.

    2007-01-01

    The productivity and residual benefits of four grain legumes to sorghum (Sorghum bicolor) grown in rotation were measured under semi-arid conditions over three cropping seasons. Two varieties of each of the grain legumes; cowpea (Vigna unguiculata); groundnut (Arachis hypogaea); pigeon pea (Cajanus

  5. Small-Scale Farming in Semi-Arid Areas: Livelihood Dynamics between 1997 and 2010 in Laikipia, Kenya

    Science.gov (United States)

    Ulrich, Anne; Speranza, Chinwe Ifejika; Roden, Paul; Kiteme, Boniface; Wiesmann, Urs; Nusser, Marcus

    2012-01-01

    The rural population of semi-arid lands in Kenya face multiple challenges that result from population growth, poor markets, land use and climatic changes. In particular, subsistence oriented farmers face various risks and opportunities in their attempt to secure their livelihoods. This paper presents an analysis on how livelihood assets and…

  6. Simply obtained global radiation, soil temperature and soil moisture in an alley cropping system in semi-arid Kenya

    NARCIS (Netherlands)

    Mungai, D.N.; Stigter, C.J.; Coulson, C.L.; Ng'ang'a, J.K.

    2000-01-01

    Global radiation, soil temperature and soil moisture data were obtained from a 4-6 year old Cassia siamea/maize (CM) alley cropping (or hedgerow intercropping) system, at a semi-arid site at Machakos, Kenya, in the late eighties. With the growing need to explore and manage variations in agro-ecosyst

  7. Phenotypic nutrient up-take differences in an alley cropping system in semi-arid Machakos, Kenya

    NARCIS (Netherlands)

    Mungai, D.N.; Coulson, C.L.; Stigter, C.J.; Ng'ang'a, J.K.; Mugendi, D.N.

    2001-01-01

    Alley cropping of Cassia siamea and maize was studied in semi-arid Kenya for soil fertility improvement. Katumani composite maize was planted except in the short rains of 1988 (SR88) when a hybrid variety was sown. Therefore the grain yield per row increased differently in the alley cropped maize (C

  8. Off-farm income, risk, and agricultural production: a case study of smallholders in India's semi-arid tropics

    NARCIS (Netherlands)

    Berg, van den M.M.

    2001-01-01

    The purpose of the current study was to determine to what extent development of the nonfarm sector stimulates crop production and agricultural employment in India's semi-arid tropics (SAT). Two characteristics of India's SAT agriculture formed the basis for the study: i) that the major agricultural

  9. Rainfed agriculture in a semi-arid tropical climate. Aspects of land- and water management for red soils in India

    NARCIS (Netherlands)

    Huibers, F.P.

    1985-01-01

    Rainfed agriculture is defined as the production of field crops that completely depend on the local precipitation for their water supply. Although in the semi-arid tropics the mean annual precipitation might seem to be sufficient to grow (adapted) crops, its variability over the years and its errati

  10. Process-based modelling of a headwater catchment in semi-arid conditions: the influence of macropore flow

    NARCIS (Netherlands)

    Schaik, N.L.M.B.; Bronstert, A.; Jong, S.M.; Jetten, V.G.; Dam, van J.C.; Ritsema, C.J.; Schnabel, S.

    2014-01-01

    Subsurface stormflow is thought to occur mainly in humid environments with steep terrains. However, in semi-arid areas, preferential flow through macropores can also result in a significant contribution of subsurface stormflow to catchment runoff for varying catchment conditions. Most hydrological m

  11. Process-based modelling of a headwater catchment in a semi-arid area : The influence of macropore flow

    NARCIS (Netherlands)

    van Schaik, N. L M B; Bronstert, A.; de Jong, S. M.; Jetten, V. G.; van Dam, J. C.; Ritsema, C. J.; Schnabel, S.

    2014-01-01

    Subsurface stormflow is thought to occur mainly in humid environments with steep terrains. However, in semi-arid areas, preferential flow through macropores can also result in a significant contribution of subsurface stormflow to catchment runoff for varying catchment conditions. Most hydrological m

  12. Water-scarcity patterns : spatiotemporal interdependencies between water use and water availability in a semi-arid river basin

    NARCIS (Netherlands)

    Oel, van Pieter Richard

    2009-01-01

    This thesis addresses the interdependencies between water use and water availability and describes a model that has been developed to improve understanding of the processes that drive changes and variations in the spatial and temporal distribution of water resources in a semi-arid river basin. These

  13. Effects of feral free-roaming horses on semi-arid rangeland ecosystems: an example from the sagebrush steppe

    Science.gov (United States)

    Feral horses (Equus caballus) are viewed as a symbol of freedom and power; however, they are also a largely unmanaged, non-native grazer in North America, South America, and Australia. Information on their influence on vegetation and soil characteristics in semi-arid rangelands has been limited by ...

  14. Soil tillage and water infiltration in semi-arid Morocco: the role fo surface and sub-surface soil conditions

    NARCIS (Netherlands)

    Dimanche, P.H.; Hoogmoed, W.B.

    2002-01-01

    Production of cereals in a dryland farming system forms an important part of agricultural production in Morocco. Yield levels on the Saïs Plateau between Meknès and Fez in the semi-arid zone, however, remain low possibly because of sub-optimum water use due to inefficient tillage systems. A study wa

  15. Approaches of Integrated Watershed Management Project: Experiences of the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)

    Science.gov (United States)

    Mula, Rosana P.; Wani, Suhas P.; Dar, William D.

    2008-01-01

    The process of innovation-development to scaling is varied and complex. Various actors are involved in every stage of the process. In scaling the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)-led integrated watershed management projects in India and South Asia, three drivers were identified--islanding approach,…

  16. 'If only it would rain': Farmers' perceptions of rainfall and drought in semi-arid central Tanzania

    NARCIS (Netherlands)

    Slegers, M.F.W.

    2008-01-01

    Farmers in semi-arid East Africa prioritize drought as their major productivity-reducing problem, while scientists identify soil degradation as a major threat. The question that needs to be addressed is how farmers perceive drought. Insight into farmers¿ perceptions of drought could be the missing l

  17. Using remote-sensing technologies in combination with Cesium-137 measurements to estimate soil-erosion quantity in semi-arid steppe areas

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Soil erosion by wind is one of the most important processes in the changing the earth’s surface in semi-arid areas,Thus it is of great importance to study soil-erosion action.Using integrated technologies of remote sensing and geochemistry radioactivity iso-tope to extract regional soil-erosion information and to calculate quantity of soil erosion is accomplished successfully in this paper by means of beneficial experiments in the Talatan region of the Gonghe Basin,which is located in northeastern Qinghai-Tibet Pla-teau in China.The results show that the soil erosion by wind is not intensive in this region;the erosion types belong to the classes of very-soft erosion and soft-erosion type,which account for 47.12 percent and 35.58 percent,respectively,of the total study area.In total,two kinds of soil erosion account for 82.70 percent of the study area;only a small area belongs to the classes of severe erosion and very-severe erosion;this area is about 22.14 km2.Severe deposition activity has taken place in this region,and has appeared in a large area(322.67 km2),which accounts for 11.78 percent of the total study area.The results of this study show that soil erosion and deposition inventories are 870,000-1,150,000 tons and 550,000-780,000 tons,respectively,per year.The soil in-ventory shows about 320,000-370,000 tons from Talatan to Longyangxia reservoir per year.Using remote-sensing technology and 137Cs techniques is a valid means to analyze and to evaluate the quantity of soil erosion by wind in semi-arid environments.

  18. Using remote-sensing technologies in combination with Cesium-137 measurements to estimate soil-erosion quantity in semi-arid steppe areas

    Institute of Scientific and Technical Information of China (English)

    ZhanJiang Sha; HaiZhou Ma; LingQin Li; Jinzhou Du; FeiQuan Wu; QiShun Fan

    2009-01-01

    Soil erosion by wind is one of the most important processes in the changing the earth's surface in semi-arid areas, Thus it is of great importance to study soil-erosion action. Using integrated technologies of remote sensing and geochemistry radioactivity isotope to extract regional soil-erosion information and to calculate quantity of soil erosion is accomplished successfully in this paper by means of beneficial experiments in the Talatan region of the Gonghe Basin, which is located in northeastern Qinghai-Tibet Plateau in China. The results show that the soil erosion by wind is not intensive in this region; the erosion types belong to the classes of very-soft erosion and soft-erosion type, which account for 47.12 percent and 35.58 percent, respectively, of the total study area.In total, two kinds of soil erosion account for 82.70 percent of the study area; only a small area belongs to the classes of severe erosion and very-severe erosion; this area is about 22.14 km2. Severe deposition activity has taken place in this region, and has appeared in a large area (322.67 km2), which accounts for 11.78 percent of the total study area. The results of this study show that soil erosion and deposition inventories are 870,000-1,150,000 tons and 550,000-780,000 tons, respectively, per year. The soil inventory shows about 320,000-370,000 tons from Talatan to Longyangxia reservoir per year. Using remote-sensing technology and 137Cs techniques is a valid means to analyze and to evaluate the quantity of soil erosion by wind in semi-arid environments.

  19. Entomological studies for surveillance and prevention of dengue in arid and semi-arid districts of Rajasthan, India

    Directory of Open Access Journals (Sweden)

    Anil Purohit

    2008-05-01

    Full Text Available Background & objectives: Rajasthan is one of the dengue endemic states of India. Very few studies have been published on entomological aspects of dengue in this state. Owing to water scarcity, inhabitants in desert areas overstore domestic water which leads to the persistence of dengue vectors within the domestic premises. Area specific knowledge on breeding, key containers and seasonal rhythms of vector population is essential for preparing an effective prevention plan against dengue. Present paper reports results of entomological investigations on dengue vectors in arid and semi-arid districts of Rajasthan. Methods: Longitudinal studies were undertaken during 2004–06 in one arid and two semi-arid dengue endemic districts of Rajasthan. Adult and larval Aedes were collected from the randomly selected houses in representative towns and villages with associated details of container types and water storage practices of inhabitants. Results: In urban areas during all the seasons adult house index (AHI of Aedes aegypti was maximum in desert zone (25 and least in semi-arid area with saline river III (1. The difference of AHI during three seasons was statistically significant (c2 = 16.1, p <0.01 for urban; and c2 = 50.71, p < 0.001 for rural. Breeding of Ae. aegypti among urban settings was maximum in desert zone. During all the seasons cement tanks were the key breeding habitats for Ae. aegypti in desert as well as semi-arid areas. Interpretation & conclusion: Water storage habits during summer season emerged to be the risk factor of vector abundance in urban areas of arid and semi-arid settings. A carefully designed study of key containers targeting cement tanks as the primary habitats of mosquito control may lead to commendable results for dengue prevention.

  20. Climate change impact on future water resources availability for a semi-arid area (Ferghana Valley, Central Asia)

    Science.gov (United States)

    Radchenko, Iuliia; Breuer, Lutz; Mannig, Birgit; Frede, Hans-Georg

    2014-05-01

    Considering increasing temperatures and glacier recession during the last decades, it is of high interest to study the climate change impact on water resources availability in semi-arid regions of Central Asia. The Ferghana Valley is surrounded by the Tien-Shan and Pamiro-Alay mountain systems that store big amounts of water in snowpacks and glaciers. In the valley the agricultural activity of local people strongly depends on available water from the Syrdarya River. The river is formed by the confluence of the Naryn and Karadarya Rivers, which are mainly fed by the glacier and snow melt from the Akshiirak and Ferghana ridges of the aforementioned mountain systems. The small upper river basins of the valley also contribute with runoff (~34 %) to the Syrdarya River. These small rivers are mainly fed by precipitation and seasonal snow melt. Thus, because of climate change and glacier decline, it is necessary to investigate the comparative contribution of the small catchments versus two big river basins to the Syrdarya River system, as these small upper catchments could become more important for future water consumption. In this study the conceptual hydrological HBV-light model has been calibrated and validated for the period 1980-1985 over 18 upper catchments that feed the Syrdarya River from the surrounding mountain ridges. Dynamically downscaled climate change scenarios were then applied up to the year 2100 for these basins. The scenarios were generated by means of Global Circulation Model (ECHAM5) and Regional Climate Model (REMO) with a baseline period from 1971 till 2000. We will present modelling results of water resources, the contribution of small rivers to the Syrdarya River and to what extent this contribution is likely to change in the future. Moreover, the results of simulated potential runoff will be used to develop future climate change adaptation strategies regarding socio-economic and environmental sustainable water use.

  1. Forests and water - Friends or foes?. Hydrological implications of deforestation and land degradation in semi-arid Tanzania

    International Nuclear Information System (INIS)

    In the study area in Babati District in Tanzania a multi-component research approach was attempted. Two catchments, one forested and one deforested-degraded, were studied regarding soil properties, runoff and groundwater recharge. This was done both in the field and with the use of two computer models: one simulating groundwater recharge as a function of rainfall variability, and one simulating hydrological implications of massive land cover conversion on the flooding of nearby Lake Babati. Three major findings came out of the study. The first is that most forested catchments (in various hydroclimates and landscapes) will increase the runoff following deforestation (due to less evapotranspiration). This is well-established knowledge, but it also depends on the actual conditions at hand. These conditions are defined as hydroclimate, soil texture and slope. In humid-temperate climates with coarse soils on flat land, the conditions strongly favor increased runoff following deforestation. However, in dry regions with fine textured soils on hilly ground, and where deforestation also implies land degradation, less dry season flow is likely to develop after a considerable adjustment period has been allowed. Secondly, the prevalence of preferential flow in a forest soil, as compared to a compacted and eroded soil, must be a key component in an explanation of why more dry season flow can emerge from a forested as compared to a deforested catchment in the dry tropics. Thirdly, there are several aspects of semi-arid and arid tropical hydrology which make comparisons with humid-temperate regions difficult and require special attention in the management of water resources in the dry tropics. 14 refs, 18 figs, 1 tab

  2. Study on Rangeland production Potential and its Limitations in the Semi-Arid lands of Northern Kenya

    International Nuclear Information System (INIS)

    Results obtained from recent studies focused on rangeland potential as influenced by human activity and climatic factors in the semi-arid and pastoral ecosystems of Northern Kenya indicated great temporal and spatial forage production variability. The objective of the studies was to document the primary production potential in relation to water stress (drought), herbivory and direct human activities. Efforts also focused on finding possibilities of increasing productivity while conserving the finite resources for sustainable use. Laboratory field and numeric methods were employed over several seasons and years. Forb and grass production was more viable than that of the brows (dwarf shrub) layer. Compared to forbs and dwarf shrubs, The grass layer contributed less to the total of production in all seasons, indicating that the region had less potential for grazers compared to browsers. Spatial-temporal variations in rangeland carrying capacity reflected the great spatial heterogeneity in vegetation types and production. Similarly, seasonal difference were very evident, with highest estimates in the long rainy and lowest during the dry and short rainy seasons, respectively. Factors limiting rangeland production potential and were identified to be moisture deficiency, resource-use conflicts, an increasing and partial sedentarised nomadic population, overgrazing, tree felling, and land degradation (desert encroachment). Measures that can increase rangelands production potential and provide a better way of life for the inhabitants of the region include: (a) identification of land degradation (e.g. by means of bio-indicators and Geographical Information systems, GIS); (b) technical interventions (i.e. soil and water conservation,restoration of degraded ares, fodder production); (c)socio-economic interventions (i.e. resolution of resource-use conflicts, alleviation of poverty, infrastructure development, improvement of livestock marketing channels, etc) and (d) continued

  3. Do protected areas networks ensure the supply of ecosystem services? Spatial patterns of two nature reserve systems in semi-arid Spain

    DEFF Research Database (Denmark)

    Castro, Antonio J.; Martín-López, Berta; López, Enrique;

    2015-01-01

    Protected areas are essential for conserving biodiversity, and these lands have traditionally been set aside for this purpose alone. However, the increasing global demand for agricultural and forestry commodities creates conflict and tradeoffs between dedicating land for conservation versus food...... that protected areas provide social and economic benefits that can be used to build political support and raise funds for conservation. We analyzed the capability of current protected area networks in the semi-arid region of Spain to provide intermediate regulating services (habitat preservation for threatened...... and groundwater recharge. Our results demonstrate that the integration of systematic analyses of ecosystem services gaps in protected area planning could contribute substantially to safeguarding ecosystem services and biodiversity jointly. However, our study also reveals substantial differences in intermediate...

  4. Using ISBA model for partitioning evapotranspiration into soil evaporation and plant transpiration of irrigated crops under semi-arid climate

    Science.gov (United States)

    Aouade, Ghizlane; Jarlan, Lionel; Ezzahar, Jamal; Er-raki, Salah; Napoly, Adrien; Benkaddour, Abdelfettah; Khabba, Said; Boulet, Gilles; Chehbouni, Abdelghani; Boone, Aaron

    2016-04-01

    The Haouz region, typical of southern Mediterranean basins, is characterized by a semi-arid climate, with average annual rainfall of 250, whilst evaporative demand is about 1600 mm per year. Under these conditions, crop irrigation is inevitable for growth and development. Irrigated agriculture currently consumes the majority of total available water (up to 85%), making it critical for more efficient water use. Flood irrigation is widely practiced by the majority of the farmers (more than 85 %) with an efficiency which does not exceed 50%. In this context, a good knowledge of the partitioning of evapotranspiration (ET) into soil evaporation and plant transpiration is of crucial need for improving the irrigation scheduling and thus water use efficiency. In this study, the ISBA (Interactions Soil-Biosphere-Atmosphere) model was used for estimating ET and its partition over an olive orchard and a wheat field located near to the Marrakech City (Centre of Morocco). Two versions were evaluated: standard version which simulates a single energy balance for the soil and vegetation and the recently developed multiple energy balance (MEB) version which solves a separate energy balance for each of the two sources. Eddy covariance system, which provides the sensible and latent heat fluxes and meteorological instruments were operated during years 2003-2004 for the Olive Orchard and during years 2013 for wheat. The transpiration component was measured using a Sap flow system during summer over the wheat crop and stable isotope samples were gathered over wheat. The comparison between ET estimated by ISBA model and that measured by the Eddy covariance system showed that MEB version yielded a remarkable improvement compared to the standard version. The root mean square error (RMSE) and the correlation coefficient (R²) were about 45wm-2 and 0.8 for MEB version. By contrast, for the standard version, the RMSE and R² were about 60wm-2 and 0.7, respectively. The result also showed that

  5. Impacts of Present and Future Climate Variability and Change on Agriculture and Forestry in the Arid and Semi-Arid Tropics

    International Nuclear Information System (INIS)

    The arid and semi-arid regions account for approximately 30% of the world total area and are inhabited by approximately 20% of the total world population. Issues of present and future climate variability and change on agriculture and forestry in the arid and semi-arid tropics of the world were examined and discussion under each of these issues had been presented separately for Asia, Africa and Latin America. Several countries in tropical Asia have reported increasing surface temperature trends in recent decades. Although, there is no definite trend discernible in the long-term mean for precipitation for the tropical Asian region, many countries have shown a decreasing trend in rainfall in the past three decades. African rainfall has changed substantially over the last 60 yr and a number of theoretical, modelling and empirical analyses have suggested that noticeable changes in the frequency and intensity of extreme events, including floods may occur when there are only small changes in climate. Climate in Latin America is affected by the El Nino-southern oscillation (ENSO) phases and there is a close relationship between the increase and decrease of rainfall depending upon the warm or cold phases of the phenomenon. Over land regions of Asia, the projected area-averaged annual mean warming is likely to be 1.6 ± 0.2C in the 2020s, 3.1 ± 0.3C in the 2050s, and 4.6 ± 0.4C in the 2080s and the models show high uncertainty in projections of future winter and summer precipitation. Future annual warming across Africa is projected to range from 0.2C per decade to more than 0.5C per decade, while future changes in mean seasonal rainfall in Africa are less well defined. In Latin America, projections indicate a slight increase in temperature and changes in precipitation. Impacts of climate variability and changes are discussed with suitable examples. Agricultural productivity in tropical Asia is sensitive not only to temperature increases, but also to changes in the nature

  6. Systematic revision of the marbled velvet geckos (Oedura marmorata species complex, Diplodactylidae) from the Australian arid and semi-arid zones.

    Science.gov (United States)

    Oliver, Paul M; Doughty, Paul

    2016-03-08

    Lizards restricted to rocky habitats often comprise numerous deeply divergent lineages, reflecting the disjunct nature of their preferred habitat and the capacity of rocky habitats to function as evolutionary refugia. Here we review the systematics and diversity of the predominantly saxicoline Australian marbled velvet geckos (genus Oedura) in the Australian arid and semi-arid zones using newly-gathered morphological data and previously published genetic data. Earlier work showed that four largely allopatric and genetically divergent lineages are present: Western (Pilbara and Gascoyne regions), Gulf (west and south of the Gulf of Carpentaria), Central (central ranges) and Eastern (Cooper and Darling Basins). None of these four populations are conspecific with true O. marmorata, a seperate species complex that is restricted to the Top End region of the Northern Territory. Top End forms share a short, bulbous tail whereas the other four lineages treated here possess a long, tapering tail. Morphological differences among the arid and semi-arid lineages include smaller body size, tapering lamellae and a shorter tail for the Gulf population, and a partially divided rostral scale in the Western population compared to the Central and Eastern populations. Accordingly, we resurrect O. cincta de Vis from synonymy for the Central and Eastern lineages, and regard this species as being comprised of two evolutionary significant units. We also describe the Gulf and Western lineages as new species: Oedura bella sp. nov. and O. fimbria sp. nov., respectively. We note that a predominantly arboreal lineage (the Eastern lineage of O. cincta) is more widely distributed than the other lineages and is phylogenetically nested within a saxicoline clade, but tend