WorldWideScience

Sample records for arid land

  1. New crops for arid lands.

    Science.gov (United States)

    Hinman, C W

    1984-09-28

    Five plants are described that could be grown commercially under arid conditions. Once the most valuable component has been obtained from each plant (rubber from guayule; seed oil from jojoba, buffalo gourd, and bladderpod; and resin from gumweed), the remaining material holds potential for useful products as well as fuel. It is difficult to realize the full potential of arid land plants, however, because of the complexities of developing the necessary agricultural and industrial infrastructure simultaneously. To do so, multicompany efforts or cooperative efforts between government and the private sector will be required.

  2. Arid Lands Biofuel

    Science.gov (United States)

    Neupane, B. P.

    2013-05-01

    Dependence on imported petroleum, as well as consequences from burning fossil fuels, has increased the demand for biofuel sources in the United States. Competition between food crops and biofuel crops has been an increasing concern, however, since it has the potential to raise prices for US beef and grain products due to land and resource competition. Biofuel crops that can be grown on land not suitable for food crops are thus attractive, but also need to produce biofuels in a financially sustainable manner. In the intermountain west of Nevada, biofuel crops need to survive on low-organic soils with limited precipitation when grown in areas that are not competing with food and feed. The plants must also yield an oil content sufficiently high to allow economically viable fuel production, including growing and harvesting the crop as well as converting the hydrocarbons into a liquid fuel. Gumweed (Grindelia squarrosa) currently appears to satisfy all of these requirements and is commonly observed throughout the west. The plant favors dry, sandy soils and is most commonly found on roadsides and other freshly disturbed land. A warm season biennial, the gumweed plant is part of the sunflower family and normally grows 2-4 feet high with numerous yellow flowers and curly leaves. The gumweed plant contains a large store of diterpene resins—most abundantly grindelic acid— similar to the saps found on pine trees that are used to make inks and adhesives. The dry weight harvest on the experimental field is 5130 lbs/acre. Whole plant biomass yields between 11-15% (average 13%) biocrude when subjected to acetone extraction whereas the buds alone contains up to a maximum of 35% biocrude when harvested in 'white milky' stage. The extract is then converted to basic form (sodium grindelate) followed by extraction of nonpolar constituents (mostly terpenes) with hexane and extracted back to ethyl acetate in acidified condition. Ethyl acetate is removed under vacuum to leave a dark

  3. Arid Lands--A Study in Ecological Disaster

    Science.gov (United States)

    Eckholm, Erik

    1977-01-01

    Reports that over-grazing and unsound agricultural practices are increasing the world-wide amount of uninhabitable land. Cites some practices which have been used to successfully reclaim arid land areas. (CP)

  4. Geothermal technoecosystems and water cycles in arid lands. Information paper

    Energy Technology Data Exchange (ETDEWEB)

    Duffield, C.

    1976-01-01

    Arid lands resource information paper No. 2, 'Exploration and Exploitation of Geothermal Resources in Arid and Semiarid Lands,' first issued in 1973, is now out-of-print. The intent of the present paper was to revise that earlier literature review with its annotated bibliography, by recognizing the unusual developments in this field in the interim, with new geothermal fields discovered, new demands for geothermal energy as an alternative source to more conventional sources, and a number of new publications reflecting accelerated research. The extensive bibliography accompanying this paper was produced by ALIS, and includes over one hundred references prepared by the Office of Arid Lands Studies.

  5. 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.

  6. Documentation of Arid Land Soilscapes in Southwestern Europe

    Science.gov (United States)

    José Ibáñez, Juan; Pérez-Gómez, Rufino; Oyonarte, Cecilio; Brevik, Eric C.

    2016-04-01

    There have been no studies to date that have proven the existence of soil assemblages typical of arid lands in Europe. This study was carried out in Almería province, a representative territory of the SE part of the Iberian Peninsula which is the driest part of Europe, to determine if soils characteristic of arid lands were present. The study made use of mathematical tools previously developed in biodiversity and pedodiversity analysis, such as richness, entropy indices, abundance distribution models, diversity-area relationships and nested subset analysis to analyse the spatial distribution of soils. The study demonstrated that the soil types or pedotaxa are typical of mountainous arid lands. Shallow and weakly developed soils (e.g. Leptosols, Regosols, Arenosols), Calcisols, Gypsisols and Solonchaks cover most of the study area, and pedodiversity analysis demonstrates that the pedotaxa spatial patterns follow the same regularities as in other areas, environments and scales. In view of the fact that the class of landscapes identified in this study are unique in Europe, the Tarbernas desert and other arid lands sites of the study area merit preservation as part of the European geological, geomorphological, and pedological heritage.

  7. New crops for arid lands. [Jojoba; Buffalo gourd; Bladderpod; Gumweed

    Energy Technology Data Exchange (ETDEWEB)

    Hinman, C.W.

    1984-09-28

    Five plants are described that could be grown commercially under arid conditions. Once the most valuable component has been obtained from each plant (rubber from guayule; seed oil from jojoba, buffalo gourd, and bladderpod; and resin from gumweed), the remaining material holds potential for useful products as well as fuel. It is difficult to realize the full potential of arid land plants, however, because of the complexities of developing the necessary agricultural and industrial infrastructure simultaneously. To do so, multicompany efforts or cooperative efforts between government and the private sector will be required.

  8. Land-atmosphere feedbacks amplify aridity increase over land under global warming

    Science.gov (United States)

    Berg, Alexis; Findell, Kirsten; Lintner, Benjamin; Giannini, Alessandra; Seneviratne, Sonia I.; van den Hurk, Bart; Lorenz, Ruth; Pitman, Andy; Hagemann, Stefan; Meier, Arndt; Cheruy, Frédérique; Ducharne, Agnès; Malyshev, Sergey; Milly, P. C. D.

    2016-09-01

    The response of the terrestrial water cycle to global warming is central to issues including water resources, agriculture and ecosystem health. Recent studies indicate that aridity, defined in terms of atmospheric supply (precipitation, P) and demand (potential evapotranspiration, Ep) of water at the land surface, will increase globally in a warmer world. Recently proposed mechanisms for this response emphasize the driving role of oceanic warming and associated atmospheric processes. Here we show that the aridity response is substantially amplified by land-atmosphere feedbacks associated with the land surface's response to climate and CO2 change. Using simulations from the Global Land Atmosphere Coupling Experiment (GLACE)-CMIP5 experiment, we show that global aridity is enhanced by the feedbacks of projected soil moisture decrease on land surface temperature, relative humidity and precipitation. The physiological impact of increasing atmospheric CO2 on vegetation exerts a qualitatively similar control on aridity. We reconcile these findings with previously proposed mechanisms by showing that the moist enthalpy change over land is unaffected by the land hydrological response. Thus, although oceanic warming constrains the combined moisture and temperature changes over land, land hydrology modulates the partitioning of this enthalpy increase towards increased aridity.

  9. How Sustainable are Engineered Rivers in Arid Lands?

    Directory of Open Access Journals (Sweden)

    Jurgen Schmandt

    2013-06-01

    Full Text Available Engineered rivers in arid lands play an important role in feeding the world’s growing population. Each continent has rivers that carry water from distant mountain sources to fertile soil downstream where rainfall is scarce. Over the course of the last century most rivers in arid lands have been equipped with large engineering structures that generate electric power and store water for agriculture and cities. This has changed the hydrology of the rivers. In this paper we discuss how climate variation, climate change, reservoir siltation, changes in land use and population growth will challenge the sustainability of engineered river systems over the course of the next few decades. We use the Rio Grande in North America, where we have worked with Mexican and American colleagues, to describe our methodology and results. Similar work is needed to study future water supply and demand in engineered rivers around the world.

  10. Arid land plants: promising new tools for economic development and basic research

    Energy Technology Data Exchange (ETDEWEB)

    Felker, P.

    1980-01-01

    An overview is presented of arid land plant development stressing products and plant physiological and ecological concepts unique to arid land plants. Integration of new arid land crops into polyculture management systems is suggested utilizing specialized plant functions, e.g., drought resistance, resistance to salinity, ability to fix nitrogen, frost tolerance and capability to produce a cash crop. Impacts on arid land plant productivity on political systems of developing countries are discussed and recommendations are presented for overcoming institutional constraints facing arid land plant development. (MHR)

  11. 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.

  12. Domesticated proboscidea parviflora: a potential oilseed crop for arid lands

    Energy Technology Data Exchange (ETDEWEB)

    Berry, J.; Bretting, P.K.; Nabhan, G.P.; Weber, C.

    1981-01-01

    Wild and domesticated Proboscidea parviflora were evaluated as oilseed crops for arid lands through chemical and biological analyses. Domesticated plants grown in the Sonoran desert bore seed containing 35-40 per cent oil and 23-27 per cent protein. Yield per hectare was estimated at 1000 kg of oil and 675 kg of protein, quantities which compare favourably with other crops. An ephemeral life cycle and certain characteristics of the fruit and seed allow this plant to grow in xeric habitats unsuitable for many other plants. Several Proboscidea species hybridize with P. parviflora and could be used in future crop breeding. Rapid germination and higher oil and protein content of seed make the domesticated P. parviflora superior to the wild form as a crop. Domesticated P. parviflora thus shows promise as an oilseed crop for the Sonoran Desert and possibly for other arid regions. (Refs. 22).

  13. Mitigating Climate Change in the Arid Lands of Namibia

    Science.gov (United States)

    Schneider, Martin B.; Sorensen, Marten

    2014-05-01

    Mitigating Climate Change in the Arid Lands of Namibia Namibia is the most arid country south of the Sahara, with scarce rainfall and perennial rivers only at its borders, > 80% of the area relies solely on groundwater. This has had devastating economic effects limiting opportunities for sustainable rural livelihoods that keep the population majority living below the World Bank poverty line (IFAD, 2013). A primary example of climatic variability which affects agrarian productivity is increased bush encroachment of Namibia's arid grazing land. The result has been a severe biodiversity loss, increased desertification and diminished water-use efficiency and underground water tables. Given these factors, Namibia's arid lands provide a unique opportunity to assess and test innovative / appropriate adaptation and mitigation strategies. Working toward sustainable management, restoration, and maintenance of balanced, resilient arid ecosystems in Namibia will also be a means to support and expand economic sectors incl. opportunities for job creation and potentially provide a model for similar arid regions. Main vegetation zones are: desert (46%), savannah (37%), and dry woodlands and forests (17%), i.e. human capacities are already in place. However, overall climate variability appears significantly higher than current plans and policies take into account. To improve livelihoods, reduce poverty, and food insecurity for rural Namibians in marginal/hyper-arid lands through sustainable climate change adaptation these objectives will be implemented: 1. Identify, assess and evaluate indigenous management strategies currently used by rural communities. 2. Capture and assess cultural and gender dimensions of management strategies within stakeholder groups using participatory approaches. 3. Determine science-based alternatives for adaptive land management strategies and test their acceptability to local communities and within the current policy framework. 4. Integrate identified

  14. Mitigating Climate Change in the Arid Lands of Namibia

    Science.gov (United States)

    Schneider, Martin B.; Sorensen, Marten

    2014-05-01

    Mitigating Climate Change in the Arid Lands of Namibia Namibia is the most arid country south of the Sahara, with scarce rainfall and perennial rivers only at its borders, > 80% of the area relies solely on groundwater. This has had devastating economic effects limiting opportunities for sustainable rural livelihoods that keep the population majority living below the World Bank poverty line (IFAD, 2013). A primary example of climatic variability which affects agrarian productivity is increased bush encroachment of Namibia's arid grazing land. The result has been a severe biodiversity loss, increased desertification and diminished water-use efficiency and underground water tables. Given these factors, Namibia's arid lands provide a unique opportunity to assess and test innovative / appropriate adaptation and mitigation strategies. Working toward sustainable management, restoration, and maintenance of balanced, resilient arid ecosystems in Namibia will also be a means to support and expand economic sectors incl. opportunities for job creation and potentially provide a model for similar arid regions. Main vegetation zones are: desert (46%), savannah (37%), and dry woodlands and forests (17%), i.e. management strategies currently used by rural communities. 2. Capture and assess cultural and gender dimensions of management strategies within stakeholder groups using participatory approaches. 3. Determine science-based alternatives for adaptive land management strategies and test their acceptability to local communities and within the current policy framework. 4. Integrate identified indigenous knowledge with appropriate science and new emerging technologies to develop a training toolkit of effective strategies relevant to all stakeholders. 5. Utilize training sessions, education workshops, curriculum revisions, and appropriate information and communication technologies (ICTs) including social media outlets to disseminate the toolkit strategies. 6. Apply a modified logic

  15. Microclimates of the arid lands ecology reserve, 1968--1975

    Energy Technology Data Exchange (ETDEWEB)

    Thorp, J. M.; Hinds, W. T.

    1977-04-01

    The climatology of the Hanford Reservation Arid Lands Ecology (ALE) Reserve does not end, of course, with this report. As this goes to press the arid lands of eastern Washington are experiencing the driest winter in 65 years of record. Even without including this winter's (1976-77) data in our summaries here, we have been fortunate to have had a very dry winter (1972-73) and a very wet winter (1973-74) occur within our first 8 years of climatological measurements on the Reserve. Our primary purpose with this report has been to analyze the first 8 years of climatological measurements from the ALE Reserve and to identify persistent spatial variations between stations or groups of stations. From these variations we have been able to recognize several distinct, but related microclimates occurring within the Reserve. Secondly, we have shown that significant correlations exist between each microclimate on the Reserve and that of the Hanford Meteorological Station nearby. These correlations, coupled with the 30-year weather record at the HMS and possibly with the 32-year (1912-1944) record at the Hanford townsite, allow ALE Reserve temperature and precipitation estimates to be made for years prior to the ALE climatology program.

  16. 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.

  17. 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 ...

  18. Arid land irrigation in the United States Pacific Northwest for 2001

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This spatial data set was created by the U.S. Geological Survey (USGS) to represent the extent of arid land irrigation in the Pacific Northwest region of the United...

  19. A brief introduction to Physical Geography of Arid Land in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A book, Physical Geography of Arid Land in China, mainly edited by Prof. Xi CHEN from Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences has been published by Science Press in July of 2010.

  20. Combining Sustainable Land Management Technologies to Combat Land Degradation and Improve Rural Livelihoods in Semi-arid Lands in Kenya

    Science.gov (United States)

    Mganga, K. Z.; Musimba, N. K. R.; Nyariki, D. M.

    2015-12-01

    Drylands occupy more than 80 % of Kenya's total land mass and contribute immensely to the national economy and society through agriculture, livestock production, tourism, and wild product harvesting. Dryland ecosystems are areas of high climate variability making them vulnerable to the threats of land degradation. Consequently, agropastoralists inhabiting these ecosystems develop mechanisms and technologies to cope with the impacts of climate variability. This study is aimed to; (1) determine what agropastoralists inhabiting a semi-arid ecosystem in Kenya attribute to be the causes and indicators of land degradation, (2) document sustainable land management (SLM) technologies being undertaken to combat land degradation, and (3) identify the factors that influence the choice of these SLM technologies. Vegetation change from preferred indigenous forage grass species to woody vegetation was cited as the main indicator of land degradation. Land degradation was attributed to recurrent droughts and low amounts of rainfall, overgrazing, and unsustainable harvesting of trees for fuelwood production. However, despite the challenges posed by climate variability and recurrent droughts, the local community is engaging in simple SLM technologies including grass reseeding, rainwater harvesting and soil conservation, and dryland agroforestry as a holistic approach combating land degradation and improving their rural livelihoods. The choice of these SLM technologies was mainly driven by their additional benefits to combating land degradation. In conclusion, promoting such simple SLM technologies can help reverse the land degradation trend, improve agricultural production, food security including access to food, and subsequently improve livelihoods of communities inhabiting dryland ecosystems.

  1. Combining Sustainable Land Management Technologies to Combat Land Degradation and Improve Rural Livelihoods in Semi-arid Lands in Kenya.

    Science.gov (United States)

    Mganga, K Z; Musimba, N K R; Nyariki, D M

    2015-12-01

    Drylands occupy more than 80% of Kenya's total land mass and contribute immensely to the national economy and society through agriculture, livestock production, tourism, and wild product harvesting. Dryland ecosystems are areas of high climate variability making them vulnerable to the threats of land degradation. Consequently, agropastoralists inhabiting these ecosystems develop mechanisms and technologies to cope with the impacts of climate variability. This study is aimed to; (1) determine what agropastoralists inhabiting a semi-arid ecosystem in Kenya attribute to be the causes and indicators of land degradation, (2) document sustainable land management (SLM) technologies being undertaken to combat land degradation, and (3) identify the factors that influence the choice of these SLM technologies. Vegetation change from preferred indigenous forage grass species to woody vegetation was cited as the main indicator of land degradation. Land degradation was attributed to recurrent droughts and low amounts of rainfall, overgrazing, and unsustainable harvesting of trees for fuelwood production. However, despite the challenges posed by climate variability and recurrent droughts, the local community is engaging in simple SLM technologies including grass reseeding, rainwater harvesting and soil conservation, and dryland agroforestry as a holistic approach combating land degradation and improving their rural livelihoods. The choice of these SLM technologies was mainly driven by their additional benefits to combating land degradation. In conclusion, promoting such simple SLM technologies can help reverse the land degradation trend, improve agricultural production, food security including access to food, and subsequently improve livelihoods of communities inhabiting dryland ecosystems. PMID:26178534

  2. Combining Sustainable Land Management Technologies to Combat Land Degradation and Improve Rural Livelihoods in Semi-arid Lands in Kenya.

    Science.gov (United States)

    Mganga, K Z; Musimba, N K R; Nyariki, D M

    2015-12-01

    Drylands occupy more than 80% of Kenya's total land mass and contribute immensely to the national economy and society through agriculture, livestock production, tourism, and wild product harvesting. Dryland ecosystems are areas of high climate variability making them vulnerable to the threats of land degradation. Consequently, agropastoralists inhabiting these ecosystems develop mechanisms and technologies to cope with the impacts of climate variability. This study is aimed to; (1) determine what agropastoralists inhabiting a semi-arid ecosystem in Kenya attribute to be the causes and indicators of land degradation, (2) document sustainable land management (SLM) technologies being undertaken to combat land degradation, and (3) identify the factors that influence the choice of these SLM technologies. Vegetation change from preferred indigenous forage grass species to woody vegetation was cited as the main indicator of land degradation. Land degradation was attributed to recurrent droughts and low amounts of rainfall, overgrazing, and unsustainable harvesting of trees for fuelwood production. However, despite the challenges posed by climate variability and recurrent droughts, the local community is engaging in simple SLM technologies including grass reseeding, rainwater harvesting and soil conservation, and dryland agroforestry as a holistic approach combating land degradation and improving their rural livelihoods. The choice of these SLM technologies was mainly driven by their additional benefits to combating land degradation. In conclusion, promoting such simple SLM technologies can help reverse the land degradation trend, improve agricultural production, food security including access to food, and subsequently improve livelihoods of communities inhabiting dryland ecosystems.

  3. Aridity/humidity status of land surface in China during the last three decades

    Institute of Scientific and Technical Information of China (English)

    WU Shaohong; YIN Yunhe; ZHENG Du; YANG Qinye

    2005-01-01

    To clarify aridity/humidity status of land surface is helpful for studying environmental background and regional differences, seeking causes of environmental change, and providing a scientific basis for researches on climate change in the future. In this paper, the authors calculated potential evapotranspiration of China using data from 616 meteorological stations during the period of 1971-2000 with the Penman-Monteith model recommanded by FAO in 1998. Vysothkii's model was used to calculate aridity/humidity index. Then the calculated results of stations were interpolated to land surface using ArcGIS. Results show that the annual average potential evapotranspiration is 400-1500 mm in the whole country, 600-800 mm in most parts of it; and 350-1400 mm in growing season (April-Octobor), which is nearly 200 mm less than the annual average. According to the aridity/humidity indexes of 1.0, 1.5 and 4.0, the aridity/humidity status is categorized to four types, namely, humid, subhumid, semiarid and arid. A majority of stations (76%) are more humid in growing season than the annual average. Results of comprisons between the distribution map of aridity/humidity index with that of precipitation and vegetation indicate a good consistence of aridity/humidity status with natural environment. Therefore potential evapotranspiration calculated with modified FAO's Penman-Monteith model in combination with aridity/humidity index that considers water balance can more reasonably explain the actual land surface aridity/humidity status of China.

  4. 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.

  5. Land Use and Environmental Variability Impacts on the Phenology of Arid Agro-Ecosystems

    Science.gov (United States)

    Romo-Leon, Jose Raul; van Leeuwen, Willem J. D.; Castellanos-Villegas, Alejandro

    2016-02-01

    The overexploitation of water resources in arid environments often results in abandonment of large extensions of agricultural lands, which may (1) modify phenological trends, and (2) alter the sensitivity of specific phenophases to environmental triggers. In Mexico, current governmental policies subsidize restoration efforts, to address ecological degradation caused by abandonments; however, there is a need for new approaches to assess their effectiveness. Addressing this, we explore a method to monitor and assess (1) land surface phenology trends in arid agro-ecosystems, and (2) the effect of climatic factors and restoration treatments on the phenology of abandoned agricultural fields. We used 16-day normalized difference vegetation index composites from the moderate resolution imaging spectroradiometer from 2000 to 2009 to derive seasonal phenometrics. We then derived phenoclimatic variables and land cover thematic maps, to serve as a set of independent factors that influence vegetation phenology. We conducted a multivariate analysis of variance to analyze phenological trends among land cover types, and developed multiple linear regression models to assess influential climatic factors driving phenology per land cover analyzed. Our results suggest that the start and length of the growing season had different responses to environmental factors depending on land cover type. Our analysis also suggests possible establishment of arid adapted species (from surrounding ecosystems) in abandoned fields with longer times since abandonment. Using this approach, we were able increase our understanding on how climatic factors influence phenology on degraded arid agro-ecosystems, and how this systems evolve after disturbance.

  6. Arid lands plants as feedstocks for fuels and chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, J.J.

    1983-01-01

    The purpose of this paper is to review the recent research on arid-adapted plants that have potential as producers of fuels or chemicals. The major focus will be on plant species that appear to have commercial value. Research on guayule (Parthenium argentatum) and jojoba (Simmondsia chinensis) will be mentioned only briefly, since these plants have been discussed extensively in the literature, and excellent reviews are already in existence. In this review the literature on arid-adapted plants that have potential uses for solid fuels, liquid fuels, and chemical feedstocks is summarized, followed by an overview of the research directions and types of development that are needed in order for bio-energy production systems to reach the commercial stage. 127 references.

  7. Theoretical critical value curve and driving force formation of ecological migration in the arid land

    Institute of Scientific and Technical Information of China (English)

    ZHU Zi'an; ZHANG Xiaolei

    2006-01-01

    The features of the fragile eco-environment of the arid land decide that its capacity of disturbance-resistance is lower. The natural desert oases in the arid land are in mosaic patches distributed in a wide Gobi desert. The population distribution is greatly dependent on water resources. The population is characterized with dispersed distribution, simple production and living style, and poverty and remoteness. The reason why the ecological migrations are carried out lies in the ecological problems. "Ecological degradation" is the main driving force of the ecological migration. Then, the strength of the driving force depends on the degree of ecological degradation. Hence, whether to carry out ecological migration depends on the extent of ecological degradation.Theoretically, the critical value curve for calculating ecological migration in the arid land is put forward through comprehensive research of relative problems of ecology, economics etc., combined with the ecological migration experience in the arid land, and based on the features of the arid environment. In this article, with this curve, the theoretical research and some practice of the ecological migration have been done from the perspective of natural behavior and governmental behavior of the driving force formation of ecological migration. It analyses the active driving force (factors) and negative forces (factors), and points out the timing and steps of implementing the ecological migration in the arid land. The theoretical curve embodies certain originality and applicability,which provides a quantitative method for evaluating 196the degree of ecological degradation and the theoretical base for implementing ecological migration projects.

  8. Land cover change drives climate extremes and aridity in non-Amazonian South America

    Science.gov (United States)

    Larsen, J.; Salazar, A.; Mcalpine, C. A.; Syktus, J.; Katzfey, J.

    2015-12-01

    Increasing evidence is showing the relevance of land cover change on the regional mean climate. However, the mechanisms that explain these interactions remain a challenge in land - atmosphere interactions science. This challenge is particularly significant in understanding the role of vegetation change on climate extremes and aridity, which has been barely addressed by the literature. In this paper we focus on this gap by investigating the effects of land use and land cover change on selected climate extremes indices and aridity in non-Amazonian South America over an area of about 3 million km2. We run a 3 ensemble climate model nudged with the ERA-Interim reanalysis and stretched to 25 km resolution for present (year 2005) land cover relative to realistic historic vegetation distribution. The most important results of this experiment are that the degree of change in vegetation structure determines whether extreme daytime temperatures will increase or decrease, particularly during the dry season. This is because a large change in surface roughness promotes increased wind speeds and heat advection, whereas a small change in surface roughness does not increase wind and can increase heat build-up in the atmosphere since the sensible heat flux also increases. We also put these results in a wider context of land surface - atmospheric feedbacks by looking at the corresponding change in aridity (precipitation / potential evapotranspiration). This shows the processes that drive the changes in temperature extremes also determine whether significant changes in aridity occur, since all the change in aridity can be prescribed to changes in potential evaporation, or atmospheric water demand. We propose a conceptual model of the mechanisms that explain these alterations which is an advance in understanding land-atmosphere interactions and provides evidence of the main mechanisms responsible of changes in the feedbacks because of changes in natural vegetation.

  9. The first Editorial Board meeting of Journal of Arid Land in 2010 was held in Urumqi

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    On Sep. 5, 2010, the first Editorial Board meeting of Journal of Arid Land (JAL) was held in Urumqi. The director of Xinjiang Institute of Ecology and Geography (XIEG), Chinese Academy of Sciences (CAS) and the editor-in-chief of JAL, Professor Chen Xi, another editor-in-chief, Professor Li Bailian, University of California,

  10. A method of characterizing land-cover swap changes in the arid zone of China

    Institute of Scientific and Technical Information of China (English)

    Yecheng YUAN; Baolin LI; Xizhang GAO; Haijiang LIU; Lili XU; Chenghu ZHOU

    2016-01-01

    Net area change analysis can dramatically underestimate total change of land cover,even sometimes seriously misinterpret ecological processes of the ecosystem,especially in arid or semiarid zones.In this paper,a suite of indices are presented to characterize land-cover swaps that may seriously damage the ecosystem in arid or semiarid zones,based on swap-change areas extracted from remotely sensed images.First,swap percentage of total area and swap intensity of total changes were used to determine the status of land-cover swap change in an area.Then,dominated swap category and individual swapchange intensity for a land-cover category were used to determine flagged land-cover swap-change categories.Finally,swap-change mode and Pielou's index were used to determine the land-cover swap-change processes of dominant categories.A case study is conducted using this approach,based on two land-cover maps in the 1980s and 2000 in Naiman Qi,Tongliao City,Inner Mongolia,China.This study shows that the approach can clearly quantify the severity and flagged classes of land-cover swap-change and reveal their relationship with ecological processes of the ecosystem.These results indicate that the approach can give deep insights into swap change,which can be very valuable to land-cover policy making and management.

  11. New crops for arid lands. [Bladderpod, gumweed, guayule, jojoba, and buffalo gourd

    Energy Technology Data Exchange (ETDEWEB)

    Hinman, C.W.

    1984-09-28

    Five plants are described that could be grown commercially under arid conditions. Once the most valuable component has been obtained from each plant (rubber from guayule; seed oil from jojoba, buffalo gourd, and bladderpod; and resin from gumweed), the remaining material holds potential for useful products as well as fuel. It is difficult to realize the full potential or arid land plants, however, because of the complexities of developing the necessary agricultural and industrial infrastructure simultaneously. To do so, multicompany efforts or cooperative efforts between government and the private sector will be required. 20 references.

  12. Plant-associated microbiomes in arid lands: diversity, ecology and biotechnological potential

    KAUST Repository

    Soussi, Asma

    2015-08-28

    Background: Aridification is a worldwide serious threat directly affecting agriculture and crop production. In arid and desert areas, it has been found that microbial diversity is huge, built of microorganisms able to cope with the environmental harsh conditions by developing adaptation strategies. Plants growing in arid lands or regions facing prolonged abiotic stresses such as water limitation and salt accumulation have also developed specific physiological and molecular stress responses allowing them to thrive under normally unfavorable conditions. Scope: Under such extreme selection pressures, special root-associated bacterial assemblages, endowed with capabilities of plant growth promotion (PGP) and extremophile traits, are selected by the plants. In this review, we provide a general overview on the microbial diversity in arid lands and deserts versus specific microbial assemblages associated with plants. The ecological drivers that shape this diversity, how plant-associated microbiomes are selected, and their biotechnological potential are discussed. Conclusions: Selection and recruitment of the plant associated bacterial assemblages is mediated by the combination of the bio-pedo-agroclimatic conditions and the plant species or varieties. Diversity and functional redundancy of these associated PGPR makes them very active in supporting plant improvement, health and resistance to drought, salt and related stresses. Implementing proper biotechnological applications of the arid and desert-adapted PGPR constitute the challenge to be raised.

  13. New Technologies to Reclaim Arid Lands User's Manual

    Energy Technology Data Exchange (ETDEWEB)

    W. K. Ostler

    2002-10-01

    Approximately 70 percent of all U.S. military training lands are located in arid and semi-arid areas. Training activities in such areas frequently adversely affect vegetation, damaging plants and reducing the resilience of vegetation to recover once disturbed. Fugitive dust resulting from a loss of vegetation creates additional problems for human health, increasing accidents due to decreased visibility, and increasing maintenance costs for roads, vehicles, and equipment. Under conventional technologies to mitigate these impacts, it is estimated that up to 35 percent of revegetation projects in arid areas will fail due to unpredictable natural environmental conditions, such as drought, and reclamation techniques that were inadequate to restore vegetative cover in a timely and cost-effective manner. New reclamation and restoration techniques are needed in desert ranges to help mitigate the adverse effects of military training and other activities to arid-land environments. In 1999, a cooperative effort between the U.S. Department of Energy (DOE), the US. Department of Defense (DoD), and selected university scientists was undertaken to focus on mitigating military impacts in arid lands. As arid lands are impacted due to DoD and DOE activities, biological and soil resources are gradually lost and the habitat is altered. A conceptual model of that change in habitat quality is described for varying levels of disturbance in the Mojave Desert. As the habitat quality degrades and more biological and physical resources are lost from training areas, greater costs are required to return the land to sustainable levels. The purpose of this manual is to assist land managers in recognizing thresholds associated with habitat degradation and provide reclamation planning and techniques that can reduce the costs of mitigation for these impacted lands to ensure sustainable use of these lands. The importance of reclamation planning is described in this manual with suggestions about

  14. Solar energy, water, and industrial systems in arid lands: technoecological overview and annotated bibliography. Information paper

    Energy Technology Data Exchange (ETDEWEB)

    Duffield, C.

    1978-01-01

    This report presents a new conceptual framework within which the countless diverse details of the burgeoning solar energy field can be unified and easily comprehended. The bibliography offers a small but typical selection from the solar energy literature. It includes mostly recent items (1975-1977), and a few important older ones. Major focus is on introductory and review publications, and specialized works dealing with arid lands and water.

  15. Arid land irrigation in the United States Pacific Northwest for 2001 summarized for NHDPlus v2 catchments

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This spatial data set was created by the U.S. Geological Survey (USGS) to represent the area of arid land irrigation in the Pacific Northwest region of the United...

  16. Regional Cost Estimates for Reclamation Practices on Arid and Semiarid Lands

    Energy Technology Data Exchange (ETDEWEB)

    W. K. Ostler

    2002-02-01

    The U.S. Army uses the Integrated Training Area Management program for managing training land. One of the major objectives of the Integrated Training Area Management program has been to develop a method for estimating training land carrying capacity in a sustainable manner. The Army Training and Testing Area Carrying Capacity methodology measures training load in terms of Maneuver Impact Miles. One Maneuver Impact Mile is the equivalent impact of an M1A2 tank traveling one mile while participating in an armor battalion field training exercise. The Army Training and Testing Area Carrying Capacity methodology is also designed to predict land maintenance costs in terms of dollars per Maneuver Impact Mile. The overall cost factor is calculated using the historical cost of land maintenance practices and the effectiveness of controlling erosion. Because land maintenance costs and effectiveness are influenced by the characteristics of the land, Army Training and Testing Area Carrying Capacity cost factors must be developed for each ecological region of the country. Costs for land maintenance activities are presented here for the semiarid and arid regions of the United States. Five ecoregions are recognized, and average values for reclamation activities are presented. Because there are many variables that can influence costs, ranges for reclamation activities are also presented. Costs are broken down into six major categories: seedbed preparation, fertilization, seeding, planting, mulching, and supplemental erosion control. Costs for most land reclamation practices and materials varied widely within and between ecological provinces. Although regional cost patterns were evident for some practices, the patterns were not consistent between practices. For the purpose of estimating land reclamation costs for the Army Training and Testing Area Carrying Capacity methodology, it may be desirable to use the ''Combined Average'' of all provinces found in the last

  17. Regional Cost Estimates for Reclamation Practices on Arid and Semiarid Lands; TOPICAL

    International Nuclear Information System (INIS)

    The U.S. Army uses the Integrated Training Area Management program for managing training land. One of the major objectives of the Integrated Training Area Management program has been to develop a method for estimating training land carrying capacity in a sustainable manner. The Army Training and Testing Area Carrying Capacity methodology measures training load in terms of Maneuver Impact Miles. One Maneuver Impact Mile is the equivalent impact of an M1A2 tank traveling one mile while participating in an armor battalion field training exercise. The Army Training and Testing Area Carrying Capacity methodology is also designed to predict land maintenance costs in terms of dollars per Maneuver Impact Mile. The overall cost factor is calculated using the historical cost of land maintenance practices and the effectiveness of controlling erosion. Because land maintenance costs and effectiveness are influenced by the characteristics of the land, Army Training and Testing Area Carrying Capacity cost factors must be developed for each ecological region of the country. Costs for land maintenance activities are presented here for the semiarid and arid regions of the United States. Five ecoregions are recognized, and average values for reclamation activities are presented. Because there are many variables that can influence costs, ranges for reclamation activities are also presented. Costs are broken down into six major categories: seedbed preparation, fertilization, seeding, planting, mulching, and supplemental erosion control. Costs for most land reclamation practices and materials varied widely within and between ecological provinces. Although regional cost patterns were evident for some practices, the patterns were not consistent between practices. For the purpose of estimating land reclamation costs for the Army Training and Testing Area Carrying Capacity methodology, it may be desirable to use the ''Combined Average'' of all provinces found in the last row of each table

  18. Small-Scale Farmer Initiatives for Irrigating the Arid and Semi-Arid Lands of Kenya

    International Nuclear Information System (INIS)

    A survey was undertaken in Machakos , Kitui, Makueni, Mwingi and Baringo districts to Identify the major systems currently being employed with a view to assessing there performance. In Machakos, Kitui, Makueni and Mwingi districts, the main sources of water were small earth dams (micro dams), with water harnessed from run off and nearby uncultivated or grazing lands. In Baringo district, the main source of water was adam constructed across a seasonal river called Wesegess. All micro dams were excavated by their owners using mainly manual labour and skills acquired from neighbours, supplemented by owner's initiates. In the areas in Eastern province, only horticultural crops are irrigated. In Baringo district, grain and horticultural crops than in grain crops underscoring their higher water demand and importance in the household cas flow. The main irrigation system employed in the Eastern province was spot, whereas furrows was widely used in Baringo district. Availability of water within the farm freed labour from fetching water long distances and shortened walking distances for livestock. It also facilitated cultivation of high value crops to improve farmers' household cash economy

  19. Impact of climate change on arid lands agriculture

    Directory of Open Access Journals (Sweden)

    El-Beltagy Adel

    2012-04-01

    Full Text Available Abstract The planet earth, on which we live in communities, is being increasingly 'ruptured' because of human activities; its carrying capacity is under great stress because of demographic pressures. The pressure is especially affecting the people living in the dry areas because of the marginal and fragile nature of the resources they have access to. There are over 2,000 million hectares of land that have been degraded, with a loss of agrobiodiversity, increased water scarcity and increased natural resource destruction. Superimposed on this is the fact that the neglectful and exploitive use of natural resources has set the train of global climate change in motion. It is anticipated that the impact of climate change will cut across all boundaries. Crops, cropping systems, rotations and biota will undergo transformation. To maintain the balance in the system, there is a need for new knowledge, alternative policies and institutional changes. The marginalized people in dry areas are likely to be most seriously hit by the shifts in moisture and temperature regimes as a result of the global climate change. To help them cope with the challenges, there is a need for a new paradigm in agricultural research and technology transfer that makes full use of modern science and technology in conjunction with traditional knowledge. This necessitates more investment by international agencies and national governments for supporting the relevant integrated research and sustainable development efforts, with full participation of the target communities. Only such an approach can enable the vulnerable communities of the dryland areas to use the natural resources in a sustainable manner and thus help protect the environment for future generations. The clock is ticking and the future of the world lies in the collective responsibility and wisdom of all nations on this planet. This should be reflected in the endorsement of a solid future plan.

  20. An overview of the spatial patterns of land surface processes over arid and semiarid regions

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    With data from the project Collaborative Observation of Semi-arid/Arid Regions in North China, collected during July and September 2008, the spatial patterns of land surface processes over arid and semiarid regions have been investigated based on the ordinary Kriging interpolation approach. Generally, for the radiation processes, downward and upward short-wave radiation have a uniformly increasing trend with latitude, but the spatial patterns of long-wave radiation present notable regional differences: both upward and downward long-wave radiation increase with latitude in the west of North China, while in the east they vary inversely with latitude, suggesting surface temperature and clouds respectively have feedbacks to the long-wave radiation in the west and east of North China. The surface net radiation basically has a negative latitudinal trend. Long-wave radiation budget plays an important role in the spatial pattern of surface net radiation, particularly in the east of North China, although short-wave radiation budget largely determines the magnitude of surface net radiation. For the energy processes, latent and sensible heat flux varies conversely with latitude: more available land surface energy is consumed by evaporating soil water at lower latitudes while more is used for heating the atmosphere at higher latitudes. A soil heat flux maximum and minimum are found in Loess Plateau and Qinghai Plateau respectively, and a maximum is seen in the northeast China.

  1. Temporal and spatial variability response of groundwater level to land use/land cover change in oases of arid areas

    Institute of Scientific and Technical Information of China (English)

    YAN Jinfeng; CHEN Xi; LUO Geping; GUO Quanjun

    2006-01-01

    This paper conducts a case study on the impacts of land use/cover change (LUCC) on the temporal and spatial variability of the groundwater level in an arid oasis in the Sangong River Watershed by using the geographical information system (GIS),remote sensing (RS) and geostatistical methods. The temporal and spatial variability of the groundwater level in the watershed in 1978, 1987 and 1998 is regressed by using thesemivariogram model and Kriging interpolation. The LUCC classification maps derived from the aerial images in 1978, Landsat TM image in 1987 and Landsat ETM image in 1998 are used to superpose and analyze the conversion relationship of LUCC types in the regions with different isograms of the groundwater depth. The results show that the change of groundwater recharge was not so significant in the whole oasis, but the temporal and spatial LUCC was significant either in the normal flow periods or in the high flow periods during the 20-year period from 1978 to 1998, and there was a close correlation between them. There is generally a moderate spatial correlation of groundwater level (33.4%),and the spatial autocorrelation distance is 17.78 km.The regions where the groundwater level is sharply changed are also the regions where the land resources are increasingly exploited, which include mainly the exploitation of farmlands, woodlands, and building, industrial and mining lands. The study reveals that the LUCC affects strongly the temporal and spatial variability of the groundwater level in the arid oasis. The study results are of direct and practical significance for rationally utilizing shallow groundwater resources and maintaining the stability of the arid oasis.

  2. Agave proves to be a low recalcitrant lignocellulosic feedstock for biofuels production on semi-arid lands

    OpenAIRE

    Li, Hongjia; Pattathil, Sivakumar; Marcus B. Foston; Ding, Shi-You; Kumar, Rajeev; Gao, Xiadi; Mittal, Ashutosh; Yarbrough, John M; Himmel, Michael E.; Ragauskas, Arthur J.; Hahn, Michael G.; Wyman, Charles E

    2014-01-01

    Background Agave, which is well known for tequila and other liquor production in Mexico, has recently gained attention because of its attractive potential to launch sustainable bioenergy feedstock solutions for semi-arid and arid lands. It was previously found that agave cell walls contain low lignin and relatively diverse non-cellulosic polysaccharides, suggesting unique recalcitrant features when compared to conventional C4 and C3 plants. Results Here, we report sugar release data from fung...

  3. Water Resources Response to Climate and Land-Cover Changes in a Semi-Arid Watershed, New Mexico, USA

    Directory of Open Access Journals (Sweden)

    Joonghyeok Heo

    2015-01-01

    Full Text Available This research evaluates a climate-land cover-water resources interconnected system in a semi-arid watershed with minimal human impact from 1970 - 2009. We found _ increase in temperature and 10.9% decrease in precipitation. The temperature exhibited a lower increase trend and precipitation showed a similar decrease trend compared to previous studies. The dominant land-cover change trend was grass and forest conversion into bush/shrub and developed land and crop land into barren and grass land. These alterations indicate that changes in temperature and precipitation in the study area may be linked to changes in land cover, although human intervention is recognized as the major land-cover change contributor for the short term. These alterations also suggest that decreasing human activity in the study area leads to developed land and crop land conversion into barren and grass land. Hydrological responses to climate and land-cover changes for surface runoff, groundwater discharge, soil water content and evapotranspiration decreased by 10.2, 10.0, 4.1, and 10.5%, respectively. Hydrological parameters generally follow similar trends to that of precipitation in semi-arid watersheds with minimal human development. Soil water content is sensitive to land-cover change and offset relatively by the changes in precipitation.

  4. Use of Sharpened Land Surface Temperature for Daily Evapotranspiration Estimation over Irrigated Crops in Arid Lands

    Science.gov (United States)

    Rosas Aguilar, J.; McCabe, M. F.; Houborg, R.; Gao, F.

    2014-12-01

    Satellite remote sensing provides data on land surface characteristics, useful for mapping land surface energy fluxes and evapotranspiration (ET). Land-surface temperature (LST) derived from thermal infrared (TIR) satellite data has been reliably used as a remote indicator of ET and surface moisture status. However, TIR imagery usually operates at a coarser resolution than that of shortwave sensors on the same satellite platform, making it sometimes unsuitable for monitoring of field-scale crop conditions. This study applies the data mining sharpener (DMS; Gao et al., 2012) technique to data from the Moderate Resolution Imaging Spectroradiometer (MODIS), which sharpens the 1 km thermal data down to the resolution of the optical data (250-500 m) based on functional LST and reflectance relationships established using a flexible regression tree approach. The DMS approach adopted here has been enhanced/refined for application over irrigated farming areas located in harsh desert environments in Saudi Arabia. The sharpened LST data is input to an integrated modeling system that uses the Atmosphere-Land Exchange Inverse (ALEXI) model and associated flux disaggregation scheme (DisALEXI) in conjunction with model reanalysis data and remotely sensed data from polar orbiting (MODIS) and geostationary (MSG; Meteosat Second Generation) satellite platforms to facilitate daily estimates of evapotranspiration. Results are evaluated against available flux tower observations over irrigated maize near Riyadh in Saudi Arabia. Successful monitoring of field-scale changes in surface fluxes are of importance towards an efficient water use in areas where fresh water resources are scarce and poorly monitored. Gao, F.; Kustas, W.P.; Anderson, M.C. A Data Mining Approach for Sharpening Thermal Satellite Imagery over Land. Remote Sens. 2012, 4, 3287-3319.

  5. Development of technology for the design of shallow land burial facilities at arid sites

    Science.gov (United States)

    Nyhan, J. W.; Abeele, W. V.; Drennon, B. J.; Herrera, W. J.; Lopez, E. A.; Langhorst, G. J.; Stallings, E. A.; Walker, R. D.; Martinez, J. L.

    The Los Alamos field research program involving technology development for arid shallow land burial (SLB) sites is described. Field data are presented for an integrated field experiment, which was designed to test individual SLB component experiments related to erosion control, biobarriers, and subsurface capillary and migration barriers. Field tests of biointrusion barriers at waste disposal sites and in experimental plots are reported. The results of a joint DOE/NRC experiment to evaluate leaching and transport of sorbing (Cs, Sr, Li) and nonsorbing (I, Br) solutes in sandy silt backfill are presented for steady-state and unsteady-state flow conditions. A capillary barrier experiment performed in a large caisson (3-m diameter, 6.1 m deep) is described and a year's worth of field data is presented.

  6. Development of technology for the design of shallow land burial facilities at arid sites

    Energy Technology Data Exchange (ETDEWEB)

    Nyhan, J.W.; Abeele, W.V.; Drennon, B.J.; Herrera, W.J.; Lopez, E.A.; Langhorst, G.J.; Stallings, E.A.; Walker, R.D.; Martinez, J.L.

    1985-01-01

    The Los Alamos field research program involving technology development for arid shallow land burial (SLB) sites is described. Field data are presented for an integrated field experiment, which was designed to test individual SLB component experiments related to erosion control, biobarriers, and subsurface capillary and migration barriers. Field tests of biointrusion barriers at waste disposal sites and in experimental plots are reported. The results of a joint DOE/NRC experiment to evaluate leaching and transport of sorbing (Cs, Sr, Li) and nonsorbing (I, Br) solutes in sandy silt backfill are presented for steady-state and unsteady-state flow conditions. A capillary barrier experiment performed in a large caisson (3-m diameter, 6.1 m deep) is described and a year's worth of field data is presented.

  7. Ecological Analysis of Deserti Fication Processes in Semi Arid Land in Algeria Using Satellite Data

    Science.gov (United States)

    Zegrar, Ahmed

    2016-07-01

    Desertification, a phenomenon of loss of productivity of the land is both a matter of Environment and Development (Cornet, 2002). It is linked to the anthropogenic action and to climate variability but also to changes in biodiversity, in particular the Maghreb (Hobbs et al., 1995). The desertification of the steppe areas of North Africa (Algeria, Morocco and Tunisia) is considered of special concern by the specialists in these regions. Desertification, Climate Change and the erosion of biodiversity are the central issues for the development of arid, semi-­arid. In this region, the combination of two factors, climatic and anthropogenic, has fostered a deterioration of the vegetation cover, soil erosion and the scarcity of water resources. The climate of this region is characterized by periods of recurring droughts since the 1970s. The anthropogenic pressure is the result of a combination of factors among which the strong demographic growth, the intensification and extension of production systems agro-­pastoral or still further the concentration of a growing livestock on smaller spaces. In this study, the criteria for classification and identification of physical parameters for spatial ecological analysis of vegetation in the steppe region to determine the degradation and vulnerability vegetation formations and how to conduct to phenomenon of desertification. So we use some satellite data in different dates (LANDSAT) in order to determine the ecological of steppe formation and changes in land cover, sand moving and forest deterioration. The application of classification and some arithmetic combination with NDVI and MSAVI2 through specific processes was used to characterize the main steppe formations. An ecological analysis of plant communities and impact of sand move describe the nature of the desertification phenomenon and allow us to determine the impact of factors of climate and entropic activity in the Algerian steppe.

  8. Towards a Remote Sensing Based Assessment of Land Susceptibility to Degradation: Examining Seasonal Variation in Land Use-Land Cover for Modelling Land Degradation in a Semi-Arid Context

    Science.gov (United States)

    Mashame, Gofamodimo; Akinyemi, Felicia

    2016-06-01

    Land degradation (LD) is among the major environmental and anthropogenic problems driven by land use-land cover (LULC) and climate change worldwide. For example, poor LULC practises such as deforestation, livestock overstocking, overgrazing and arable land use intensification on steep slopes disturbs the soil structure leaving the land susceptible to water erosion, a type of physical land degradation. Land degradation related problems exist in Sub-Saharan African countries such as Botswana which is semi-arid in nature. LULC and LD linkage information is still missing in many semi-arid regions worldwide.Mapping seasonal LULC is therefore very important in understanding LULC and LD linkages. This study assesses the impact of seasonal LULC variation on LD utilizing Remote Sensing (RS) techniques for Palapye region in Central District, Botswana. LULC classes for the dry and rainy seasons were classified using LANDSAT 8 images at Level I according to the Food and Agriculture Organization (FAO) International Organization of Standardization (ISO) code 19144. Level I consists of 10 LULC classes. The seasonal variations in LULC are further related to LD susceptibility in the semi-arid context. The results suggest that about 985 km² (22%) of the study area is susceptible to LD by water, major LULC types affected include: cropland, paved/rocky material, bare land, built-up area, mining area, and water body. Land degradation by water susceptibility due to seasonal land use-land cover variations is highest in the east of the study area where there is high cropland to bare land conversion.

  9. 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...

  10. Transitions in Land Use Architecture under Multiple Human Driving Forces in a Semi-Arid Zone

    Directory of Open Access Journals (Sweden)

    Issa Ouedraogo

    2015-07-01

    Full Text Available The present study aimed to detect the main shifts in land-use architecture and assess the factors behind the changes in typical tropical semi-arid land in Burkina Faso. Three sets of time-series LANDSAT data over a 23-year period were used to detect land use changes and their underpinning drivers in multifunctional but vulnerable ecologies. Group discussions in selected villages were organized for mapping output interpretation and collection of essential drivers of change as perceived by local populations. Results revealed profound changes and transitions during the study period. During the last decade, shrub and wood savannahs exhibited high net changes (39% and −37% respectively with a weak net positive change for cropland (only 2%, while cropland and shrub savannah exhibited high swap (8% and 16%. This suggests that the area of cropland remained almost unchanged but was subject to relocation, wood savannah decreased drastically, and shrub savannah increased exponentially. Cropland exhibited a null net persistence while shrub and wood savannahs exhibited positive and negative net persistence (1.91 and −10.24, respectively, indicating that there is movement toward agricultural intensification and wood savannah tended to disappear to the benefit of shrub savannah. Local people are aware of the changes that have occurred and support the idea that illegal wood cutting and farming are inappropriate farming practices associated with immigration; absence of alternative cash generation sources, overgrazing and increasing demand for wood energy are driving the changes in their ecosystems. Policies that integrate restoration and conservation of natural ecosystems and promote sustainable agroforestry practices in the study zone are highly recommended.

  11. On the sensitivity of Land Surface Temperature estimates in arid irrigated lands using MODTRAN

    KAUST Repository

    Rosas, Jorge

    2015-11-29

    Land surface temperature (LST) derived from thermal infrared (TIR) satellite data has been reliably used as a remote indicator of evapotranspiration (ET) and surface moisture status. However, in order to retrieve the ET with an accuracy approaching 10%, LST should be retrieved to within 1 ◦C or better, disregarding other elements of uncertainty. The removal of atmospheric effects is key towards achieving a precise estimation of LST and it requires detailed information on water vapor. The Thermal Infrared Sensor (TIRS) onboard Landsat 8 captures data in two long wave thermal bands with 100-meter resolution. However, the US Geological Survey has reported a calibration problem of TIRS bands caused by stray light, resulting in a higher bias in one of its two bands (4% in band 11, 2% in band 10). Therefore, split-window algorithms for the estimation of LST might not be reliable. Our work will focus on the impact of using different atmospheric profiles (e.g. weather prediction models, satellite) for the estimation of LST derived from MODTRAN by using one of the TIRS bands onboard Landsat 8 (band 10). Sites with in-situ measurements of LST are used as evaluation sources. Comparisons between the measured LST and LST derived based on different atmospheric profile inputs to MODTRAN are carried out from 2 Landsat-overpass days (DOY 153 and 160 2015). Preliminary results show a mean absolute error of around 3 ◦C between in-situ and estimated LST over two different crops (alfalfa and carrot) and bare soil.

  12. A "win-win" scenario: the use of sustainable land management technologies to improve rural livelihoods and combat desertification in semi-arid lands in Kenya

    Science.gov (United States)

    Mganga, Kevin; Musimba, Nashon; Nyariki, Dickson; Nyangito, Moses; Mwang'ombe, Agnes

    2014-05-01

    Dryland ecosystems support over 2 billion people and are major providers of critical ecosystems goods and services globally. However, desertification continues to pose a serious threat to the sustainability of the drylands and livelihoods of communities inhabiting them. The desertification problem is well exemplified in the arid and semi-arid lands (ASALs) in Kenya which cover approximately 80% of the total land area. This study aimed to 1) determine what agropastoralists attribute to be the causes of desertification in a semi-arid land in Kenya, 2) document sustainable land management (SLM) technologies being undertaken to improve livelihoods and combat desertification, and 3) identify the factors that influence the choice of the sustainable land management (SLM) technologies. Results show that agropastoralists inhabiting the semi-arid lands in southeastern Kenya mainly attribute desertification to the recurrent droughts and low amounts of rainfall. Despite the challenges posed by desertification and climate variability, agropastoralists in the study area are using a combination of SLM technologies notably dryland agroforestry using drought tolerant species (indigenous and exotic), grass reseeding using perennial native and drought tolerant grass species (vegetation reestablishment) and in-situ rainwater harvesting to improve livelihoods and by extension combat desertification. Interestingly, the choice and adoption of these SLM technologies is influenced more by the additional benefits the agropastoralists can derive from them. Therefore, it is rationale to conclude that success in dryland restoration and combating desertification lies in programs and technologies that offer a "win-win" scenario to the communities inhabiting the drylands. Key words: Agroforestry; Agropastoralists; Drylands; Grass Reseeding; Rainwater Harvesting

  13. 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.

  14. Agave proves to be a low recalcitrant lignocellulosic feedstock for biofuels production on semi-arid lands

    Science.gov (United States)

    2014-01-01

    Background Agave, which is well known for tequila and other liquor production in Mexico, has recently gained attention because of its attractive potential to launch sustainable bioenergy feedstock solutions for semi-arid and arid lands. It was previously found that agave cell walls contain low lignin and relatively diverse non-cellulosic polysaccharides, suggesting unique recalcitrant features when compared to conventional C4 and C3 plants. Results Here, we report sugar release data from fungal enzymatic hydrolysis of non-pretreated and hydrothermally pretreated biomass that shows agave to be much less recalcitrant to deconstruction than poplar or switchgrass. In fact, non-pretreated agave has a sugar release five to eight times greater than that of poplar wood and switchgrass . Meanwhile, state of the art techniques including glycome profiling, nuclear magnetic resonance (NMR), Simon’s Stain, confocal laser scanning microscopy and so forth, were applied to measure interactions of non-cellulosic wall components, cell wall hydrophilicity, and enzyme accessibility to identify key structural features that make agave cell walls less resistant to biological deconstruction when compared to poplar and switchgrass. Conclusions This study systematically evaluated the recalcitrant features of agave plants towards biofuels applications. The results show that not only does agave present great promise for feeding biorefineries on semi-arid and arid lands, but also show the value of studying agave’s low recalcitrance for developments in improving cellulosic energy crops. PMID:24708685

  15. 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

  16. GRACE Gravity Satellite Observations of Terrestrial Water Storage Changes for Drought Characterization in the Arid Land of Northwestern China

    OpenAIRE

    Yanping Cao; Zhuotong Nan; Guodong Cheng

    2015-01-01

    Drought is a complex natural hazard which can have negative effects on agriculture, economy, and human life. In this paper, the primary goal is to explore the application of the Gravity Recovery and Climate Experiment (GRACE) gravity satellite data for the quantitative investigation of the recent drought dynamic over the arid land of northwestern China, a region with scarce hydrological and meteorological observation datasets. The spatiotemporal characteristics of terrestrial water storage ch...

  17. Long-term effect of land use change on soil quality: Afforestation and land abandonment in semi-arid Spain

    Science.gov (United States)

    Zethof, Jeroen; Cammeraat, Erik; Nadal-Romero, Estela

    2016-04-01

    Soils under the Mediterranean climate are vulnerable for degradation, especially after land abandonment. Abandonment is an important factor in the Mediterranean landscape as vegetation regeneration is hampered due to the characteristic semi-arid and sub-humid Mediterranean climate regime. During the past 70 year extensive afforestation projects have been conducted with the aim to protect landscapes and soils against degradation. While large investments are still being made, little is known about the impact of afforestation on soil quality on a longer time scale. During the past decade, there is a growing interest in qualifying and quantifying the carbon storage in soils by such afforestation projects, to get a better understanding of the carbon cycle and look for possibilities to fixate atmospheric CO2 in the soil. It is generally accepted that afforestation projects will increase the soil carbon pool, but data on this process is scarce. Therefore an intensive fieldwork has been carried out in Murcia, southeastern Spain to study the effects of land abandonment and afforestation on soil quality along a chronosequence and included two afforested areas (from the early '70s and 1993). The Pinus halepensis trees were planted in rows, for which the underlying calcrete was broken. Samples were taken to study changes in soil quality (Aggregate stability, Corg, N, P, K, Na), Soil Organic Carbon (SOC) stocks and soil hydraulic properties, such as infiltration and water retention, between the afforestation projects, abandoned agricultural plots of similar age, semi-natural vegetation, cereal crop fields and almond orchards. As the natural vegetation is characterized by a spotted pattern of bare areas and trees, forming so-called "islands of fertility", both bare and vegetation covered sub-sites were sampled. First results showed a positive effect of both land abandonment and afforestation on the soil aggregation. Especially the 40-year-old plots showed underneath trees

  18. Impact of climate and analysis of desertification processes in semi arid land in Algeria: using data of Alsat-1 and Landsat

    OpenAIRE

    Ahmed, Z; Habib, M; Sid Ali, H.; Sofiane, K.

    2015-01-01

    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...

  19. Detection and prediction of land cover changes using Markov chain model in semi-arid rangeland in western Iran.

    Science.gov (United States)

    Fathizad, Hassan; Rostami, Noredin; Faramarzi, Marzban

    2015-10-01

    The study of changes and destruction rate in the previous years as well as the possibility of prediction of these changes in the following years has a key role in optimal planning, controlling, and restricting non-normative changes in the future. This research was approached to detecting land use/cover changes (1985-2007) and to forecast the changes in the future (2021) use of multitemporal satellite imagery in semi-arid area in western Iran. A supervised classification of multilayer perceptron (MLP) was applied for detecting land use changes. The study area was classified into five classes, those of forest, rangeland, agriculture, residential, and barren lands. The change detection analysis indicated a decreasing trend in forest cover by 30.42%, while other land uses were increased during 1985 to 2007. The land use changes were predicted using Markov chain model for 2021. The model was calibrated by comparing the simulated map with the real detected classes of land cover in 2007. Then, for further model processing, an acceptable accuracy at 83% was achieved between them. Finally, land use changes were predicted by using transition matrix derived from calibrated approach. The findings of this study demonstrate a rapid change in land use/cover for the coming years. Transforming the forest into other land uses especially rangeland and cropland is the main land cover changes in the future. Therefore, the planning of protection and restoration of forest cover should be an essential program for decision-makers in the study area. PMID:26373304

  20. Land Cover Land Use change and soil organic carbon under climate variability in the semi-arid West African Sahel (1960-2050)

    Science.gov (United States)

    Dieye, Amadou M.

    Land Cover Land Use (LCLU) change affects land surface processes recognized to influence climate change at local, national and global levels. Soil organic carbon is a key component for the functioning of agro-ecosystems and has a direct effect on the physical, chemical and biological characteristics of the soil. The capacity to model and project LCLU change is of considerable interest for mitigation and adaptation measures in response to climate change. A combination of remote sensing analyses, qualitative social survey techniques, and biogeochemical modeling was used to study the relationships between climate change, LCLU change and soil organic carbon in the semi-arid rural zone of Senegal between 1960 and 2050. For this purpose, four research hypotheses were addressed. This research aims to contribute to an understanding of future land cover land use change in the semi-arid West African Sahel with respect to climate variability and human activities. Its findings may provide insights to enable policy makers at local to national levels to formulate environmentally and economically adapted policy decisions. This dissertation research has to date resulted in two published and one submitted paper.

  1. Coupled Soil Water and Heat Transport Near the Land Surface in Arid and Semiarid Regions - Multi-Domain Modeling

    Science.gov (United States)

    Mohanty, Binayak; Yang, Zhenlei

    2016-04-01

    Understanding and simulating coupled water and heat transfer appropriately in the shallow subsurface is of vital significance for accurate prediction of soil evaporation that would improve the coupling between land surface and atmosphere, which consequently could enhance the reliability of weather as well as climate forecast. The theory of Philip and de Vries (1957), accounting for water vapor diffusion only, was considered physically incomplete and consequently extended and improved by several researchers by explicitly taking water vapor convection, dispersion or air flow into account. It is generally believed that the soil moisture is usually low in the near surface layer under highly transient field conditions, particularly in arid and semiarid regions, and that accurate characterization of water vapor transport is critical when modeling simultaneous water and heat transport in the shallow field soils. The first objective of this study is thus mainly to test existing coupled water and heat transport theories and to develop reasonable and simplified numerical models using field experimental data collected under semi-arid and arid hydro-climatic conditions. In addition, more complex multi-domain models are developed for ubiquitous heterogeneous terrestrial surfaces such as horizontal textural contrasts or structured heterogeneity including macropores (fractures, cracks, root channels, etc.). This would make coupled water and heat transfer models applicable in such non-homogeneous soils more meaningful and enhance the skill of land-atmosphere interaction models at a larger context.

  2. Developing User-Driven Climate Information Services to Build Resilience Amongst Groups at Risk of Drought and Flood in Arid and Semi-Arid Land Counties in Kenya

    Science.gov (United States)

    Githungo, W. N.; Shaka, A.; Kniveton, D.; Muithya, L.; Powell, R.; Visman, E. L.

    2014-12-01

    The Arid and Semi-Arid Land (ASAL) counties of Kitui and Makueni in Kenya are experiencing increasing climate variability in seasonal rainfall, including changes in the onset, cessation and distribution of the two principal rains upon which the majority of the population's small-holder farmers and livestock keepers depend. Food insecurity is prevalent with significant numbers also affected by flooding during periods of intense rainfall. As part of a multi-partner Adaptation Consortium, Kenya Meteorological Services (KMS) are developing Climate Information Services (CIS) which can better support decision making amongst the counties' principal livelihoods groups and across County Government ministries. Building on earlier pilots and stakeholder discussion, the system combines the production of climate information tailored for transmission via regional and local radio stations with the establishment of a new SMS service. SMS are provided through a network of CIS intermediaries drawn from across key government ministries, religious networks, non-governmental and community groups, aiming to achieve one SMS recipient per 3-500 people. It also introduces a demand-led, premium-rate SMS weather information service which is designed to be self-financing in the long term. Supporting the ongoing process of devolution, KMS is downscaling national forecasts for each county, and providing seasonal, monthly, weekly and daily forecasts, as well as warnings of weather-related hazards. Through collaboration with relevant ministries, government bodies and research institutions, including livestock, agriculture, drought management and health, technical advisories are developed to provide guidance on application of the climate information. The system seeks to provide timely, relevant information which can enable people to use weather and climate information to support decisions which protect life and property and build resilience to ongoing climate variability and future change.

  3. Preliminary criteria for shallow-land storage/disposal of low-level radioactive solid waste in an arid environment

    International Nuclear Information System (INIS)

    Preliminary criteria for shallow land storage/disposal of low level radioactive solid waste in an arid environment were developed. Criteria which address the establishment and operation of a storage/disposal facility for low-level radioactive solid wastes are discussed. These were developed from the following sources: (1) a literature review of solid waste burial; (2) a review of the regulations, standards, and codes pertinent to the burial of radioactive wastes; (3) on site experience; and (4) evaluation of existing burial grounds and practices

  4. Hydrological response to land cover changes and human activities in arid regions using a geographic information system and remote sensing.

    Science.gov (United States)

    Mahmoud, Shereif H; Alazba, A A

    2015-01-01

    The hydrological response to land cover changes induced by human activities in arid regions has attracted increased research interest in recent decades. The study reported herein assessed the spatial and quantitative changes in surface runoff resulting from land cover change in the Al-Baha region of Saudi Arabia between 1990 and 2000 using an ArcGIS-surface runoff model and predicted land cover and surface runoff depth in 2030 using Markov chain analysis. Land cover maps for 1990 and 2000 were derived from satellite images using ArcGIS 10.1. The findings reveal a 26% decrease in forest and shrubland area, 28% increase in irrigated cropland, 1.5% increase in sparsely vegetated land and 0.5% increase in bare soil between 1990 and 2000. Overall, land cover changes resulted in a significant decrease in runoff depth values in most of the region. The decrease in surface runoff depth ranged from 25-106 mm/year in a 7020-km2 area, whereas the increase in such depth reached only 10 mm/year in a 243-km2 area. A maximum increase of 73 mm/year was seen in a limited area. The surface runoff depth decreased to the greatest extent in the central region of the study area due to the huge transition in land cover classes associated with the construction of 25 rainwater harvesting dams. The land cover prediction revealed a greater than twofold increase in irrigated cropland during the 2000-2030 period, whereas forest and shrubland are anticipated to occupy just 225 km2 of land area by 2030, a significant decrease from the 747 km2 they occupied in 2000. Overall, changes in land cover are predicted to result in an annual increase in irrigated cropland and dramatic decline in forest area in the study area over the next few decades. The increase in surface runoff depth is likely to have significant implications for irrigation activities.

  5. Hydrological response to land cover changes and human activities in arid regions using a geographic information system and remote sensing.

    Directory of Open Access Journals (Sweden)

    Shereif H Mahmoud

    Full Text Available The hydrological response to land cover changes induced by human activities in arid regions has attracted increased research interest in recent decades. The study reported herein assessed the spatial and quantitative changes in surface runoff resulting from land cover change in the Al-Baha region of Saudi Arabia between 1990 and 2000 using an ArcGIS-surface runoff model and predicted land cover and surface runoff depth in 2030 using Markov chain analysis. Land cover maps for 1990 and 2000 were derived from satellite images using ArcGIS 10.1. The findings reveal a 26% decrease in forest and shrubland area, 28% increase in irrigated cropland, 1.5% increase in sparsely vegetated land and 0.5% increase in bare soil between 1990 and 2000. Overall, land cover changes resulted in a significant decrease in runoff depth values in most of the region. The decrease in surface runoff depth ranged from 25-106 mm/year in a 7020-km2 area, whereas the increase in such depth reached only 10 mm/year in a 243-km2 area. A maximum increase of 73 mm/year was seen in a limited area. The surface runoff depth decreased to the greatest extent in the central region of the study area due to the huge transition in land cover classes associated with the construction of 25 rainwater harvesting dams. The land cover prediction revealed a greater than twofold increase in irrigated cropland during the 2000-2030 period, whereas forest and shrubland are anticipated to occupy just 225 km2 of land area by 2030, a significant decrease from the 747 km2 they occupied in 2000. Overall, changes in land cover are predicted to result in an annual increase in irrigated cropland and dramatic decline in forest area in the study area over the next few decades. The increase in surface runoff depth is likely to have significant implications for irrigation activities.

  6. The potential of intercropping food crops and energy crop to improve productivity of a degraded agriculture land in arid tropics

    Directory of Open Access Journals (Sweden)

    I.K.D. Jaya

    2014-04-01

    Full Text Available Degraded agricultural lands in the arid tropics have low soil organic carbon (SOC and hence low productivity. Poor farmers that their livelihoods depend highly on these types of lands are suffering. Cropping strategies that are able to improve the soil productivity are needed. In the present study, some intercropping models of food crops with bio-energy crop of castor (Ricinus communis L. were tested to assess their potential to improve the degraded land productivity. The intercropping models were: (1 castor - hybrid maize, (2 castor – short season maize, (3 castor – mungbean, and (4 castor –short season maize – mungbean. The results show that yields of the component crops in monoculture were relatively the same as in intercropping, resulted in a high Land Equivalent Ratio (LER. The highest LER (3.07 was calculated from intercropping castor plants with short season maize crops followed by mungbean with intercropping productivity of IDR 15,097,600.00 ha-1. Intercropping has a great potential to improve degraded agriculture land productivity and castor is a promising plant to improve biodiversity and area coverage on the land.

  7. Seed viability and germination success of Acacia tortilis along land-use and aridity gradients in the Eastern Sahara.

    Science.gov (United States)

    Andersen, Gidske Leknæs; Krzywinski, Knut; Gjessing, Håkon K; Pierce, Richard Holton

    2016-01-01

    Our study focuses on the keystone species Acacia tortilis and is the first to investigate the effect of domestic ungulates and aridity on seed viability and germination over an extensive part of the Eastern Sahara. Bruchids infest its seeds and reduce their viability and germination, but ingestion by ruminant herbivores diminishes infestation levels and enhances/promotes seed viability and germination. The degree of these effects seems to be correlated with animal body mass. Significantly reduced numbers of wild ruminant ungulates have increased the potential importance of domestic animals and pastoral nomadism for the functionality of arid North African and Middle Eastern ecosystems. We sampled seeds (16,543) from A. tortilis in eight areas in three regions with different aridity and land use. We tested the effect of geography and sampling context on seed infestation using random effects logistic regressions. We did a randomized and balanced germination experiment including 1193 seeds, treated with different manure. Germination time and rates across geography, sampling context, and infestation status were analyzed using time-to-event analyses, Kaplan-Meier curves and proportional hazards Cox regressions. Bruchid infestation is very high (80%), and the effects of context are significant. Neither partial infestation nor adding manure had a positive effect on germination. There is a strong indication that intact, uningested seeds from acacia populations in the extremely arid Western Desert germinate more slowly and have a higher fraction of hard seeds than in the Eastern Desert and the Red Sea Hills. For ingested seeds in the pastoralist areas we find that intact seeds from goat dung germinate significantly better than those from camel dung. This is contrary to the expected body-mass effect. There is no effect of site or variation in tribal management. PMID:26811790

  8. 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.

  9. Getting ‘holistic’ about land rehabilitation in hot arid regions

    Institute of Scientific and Technical Information of China (English)

    Adrian Williams

    2002-01-01

    The paper describes Western Australian examples and causes of land degradation. Itoutlines shortcomings in the methodologies used to rehabilitate these areas. From this a protocolis suggested for an ‘holistic' approach to land rehabilitation.

  10. LAND SUITABILITY SCENARIOS FOR ARID COASTAL PLAINS USING GIS MODELING: SOUTHWESTERN SINAI COASTAL PLAIN, EGYPT

    OpenAIRE

    Ahmed Mohamed Wahid; Marguerite Madden; Fikry Khalaf; Ibtehal Fathy

    2009-01-01

    Site selection analysis was carried out to find the best suitable lands for development activities in an example of promising coastal plains, southwestern Sinai, Egypt. Two GIS models were developed to represent two scenarios of land use suitability in the study area using GIS Multi Criteria Analysis Modeling. The factors contributed in the analysis are the Topography, Land cover, Existing Land use, Flash flood index, Drainage lines and Water points. The first scenario was to classify the are...

  11. 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

  12. Response of soil nutrients to different cropping systems in the oasis of arid land

    Institute of Scientific and Technical Information of China (English)

    XU Wenqiang; LUO Geping; CHEN Xi

    2006-01-01

    In the process of transformation of tropic rain forest and semi-arid grassland to farmland, the soil degradation usually occurs. But the transformation of arid desert to oasis is likely to differ from that of tropic rain forest and semi-arid grassland. Taking an alluvial plain oasis as a study case, the oasis soil properties during the process of the transformation of different cropping systems have been investigated and evaluated. Selected cropping systems consist of saline tolerance crop (STC), food crop (FC), melon and vegetables (MV), Economic plants-cotton (EP-C),economic plants-grape (EP-G), Economic plants-Hop (EP-H). Surface soil (0-20 cm) samples were collected in 1982, 1999 and 2003. Soil, organic matter (OM), and available N (AN), available P (AP) and available K (AK) were determined for each soil sample. SPSS statistical software was used to analyze the soil property data. The transformation of cropping systems in the Sangong River watershed was affected directly by the policy, law and market. The soil OM contents experienced a decline during 1982-1999, then a rise during 1999-2003. AN, AP and AK contents increased significantly with cultivated time.Soil OM tends to decrease during the conversion from STC and FC to cotton but increase during the conversion from the cotton to the grape. The soil OM was increased gradually with the cultivation time, so the oasis soil presented carbon sink, which indicates that human activities was reasonable and favorable for improvement of the oasis-ecosystem.

  13. Recycled Urban Wastewater for Irrigation of Jatropha curcas L. in Abandoned Agricultural Arid Land

    Directory of Open Access Journals (Sweden)

    María Dorta-Santos

    2014-10-01

    Full Text Available In a global context in which obtaining new energy sources is of paramount importance, the production of biodiesel from plant crops is a potentially viable alternative to the use of fossil fuels. Among the species used to produce the raw material for biodiesel, Jatropha curcas L. (JCL has enjoyed increased popularity in recent years, due partly to its ability to grow in degraded zones and under arid and semi-arid conditions. The present study evaluates the potential for JCL production under irrigation with non-conventional water resources in abandoned agricultural soils of the island of Fuerteventura (Canary Islands, Spain, which is one of the most arid parts of the European Union. JCL growth and productivity are compared during the first 39 months of cultivation in two soil types (clay-loam and sandy-loam and with two irrigation water qualities: recycled urban wastewater (RWW and desalinated brackish water (DBW. The results indicate that JCL growth (in terms of plant height and stem diameter was significantly influenced both by soil type and water quality, with better development observed in the sandy-loam soil under RWW irrigation. Productivity, measured as cumulative seed production, was not affected by soil type but was affected by water quality. Production under RWW irrigation was approximately seven times greater than with DBW (mean ~2142 vs. 322 kg·ha−1. The higher nutrient content, especially P, K and Mg, and lower B content of the RWW were found to be key factors in the greater productivity observed under irrigation with this type of water.

  14. Field studies of erosion-control technologies for arid shallow land-burial sites at Los Alamos

    International Nuclear Information System (INIS)

    The field research program involving corrective measures technologies for arid shallow land-burial sites is described. Research performed for a portion of this task, the identification, evaluation, and modeling of erosion control technologies, is presented in detail. In a joint study with USDA-ARS, soil erosion and infiltration of water into a simulated trench cap with various surface treatments was measured and compared with data from undisturbed soil surfaces with natural plant cover. The distribution of soil particles in the runoff was measured for inclusion in CREAMS (a field scale model for Chemicals, Runoff and Erosion from Agricultural Management Systems). Neutron moisture gauge data collected beneath the erosion plots are presented to show the seasonal effects of the erosion control technologies on the subsurface component of water balance. 12 references, 4 figures, 4 tables

  15. Solar energy, water and industrial systems in arid lands: techno-ecological overview and annotated bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Duffield, C.P.

    1978-01-01

    Techno-ecology is described as the study of large complex industrial systems in a manner analogous to the analysis of biological ecosystems. This study serves as a framework within which diverse solar energy technologies can be holistically comprehended and managed. Solar energy systems and sun-powered bio-ecosystems are seen to have many parallels at the organizational and ecosystem levels, with solar collectors being analogous to plants in design, organization and adaptation to arid conditions. Solar technologies for water processing (pumps, drainage, storage conservation and desalination and evaporation) and use (solar energy collection, storage, distribution; cooling; and helio-hydroelectric and salinity gradient power plants) are reviewed. It is seen that the complex symbiosis of solar and water technologies may prove advantageous. Large solar energy systems could counteract desertification and atmospheric CO/sub 2/ increases. Solar energy technologies are seen to be vital to the future survival or arid, oil-rich countries with their use in other developing countries also of importance at the appropriate scale. 100 abstracts are included in the bibliography. 133 references.

  16. Simulating the hydrologic impacts of land cover and climate changes in a semi-arid watershed

    Data.gov (United States)

    U.S. Environmental Protection Agency — Changes in climate and land cover are among the principal variables affecting watershed hydrology. This paper uses a cell-based model to examine the hydrologic...

  17. 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...

  18. Evaluating the use of sharpened land surface temperature for daily evapotranspiration estimation over irrigated crops in arid lands

    KAUST Repository

    Rosas, Jorge

    2014-12-01

    Satellite remote sensing provides data on land surface characteristics, useful for mapping land surface energy fluxes and evapotranspiration (ET). Land-surface temperature (LST) derived from thermal infrared (TIR) satellite data has been reliably used as a remote indicator of ET and surface moisture status. However, TIR imagery usually operates at a coarser resolution than that of shortwave sensors on the same satellite platform, making it sometimes unsuitable for monitoring of field-scale crop conditions. This study applies the data mining sharpener (DMS; Gao et al., 2012) technique to data from the Moderate Resolution Imaging Spectroradiometer (MODIS), which sharpens the 1 km thermal data down to the resolution of the optical data (250-500 m) based on functional LST and reflectance relationships established using a flexible regression tree approach. The DMS approach adopted here has been enhanced/refined for application over irrigated farming areas located in harsh desert environments in Saudi Arabia. The sharpened LST data is input to an integrated modeling system that uses the Atmosphere-Land Exchange Inverse (ALEXI) model and associated flux disaggregation scheme (DisALEXI) in conjunction with model reanalysis data and remotely sensed data from polar orbiting (MODIS) and geostationary (MSG; Meteosat Second Generation) satellite platforms to facilitate daily estimates of evapotranspiration. Results are evaluated against available flux tower observations over irrigated maize near Riyadh in Saudi Arabia. Successful monitoring of field-scale changes in surface fluxes are of importance towards an efficient water use in areas where fresh water resources are scarce and poorly monitored. Gao, F.; Kustas, W.P.; Anderson, M.C. A Data Mining Approach for Sharpening Thermal Satellite Imagery over Land. Remote Sens. 2012, 4, 3287-3319.

  19. 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

  20. LAND SUITABILITY SCENARIOS FOR ARID COASTAL PLAINS USING GIS MODELING: SOUTHWESTERN SINAI COASTAL PLAIN, EGYPT

    Directory of Open Access Journals (Sweden)

    Ahmed Mohamed Wahid

    2009-12-01

    Full Text Available Site selection analysis was carried out to find the best suitable lands for development activities in an example of promising coastal plains, southwestern Sinai, Egypt. Two GIS models were developed to represent two scenarios of land use suitability in the study area using GIS Multi Criteria Analysis Modeling. The factors contributed in the analysis are the Topography, Land cover, Existing Land use, Flash flood index, Drainage lines and Water points. The first scenario was to classify the area according to various gradual ranges of suitability. According to this scenario, the area is classified into five classes of suitability. The percentage of suitability values are 51.16, 6.13, 22.32, 18.49 and 1.89% for unsuitable, least suitable, low suitable, suitable and high suitable, respectively. The second scenario is developed for a particular kind of land use planning; tourism and recreation projects. The suitability map of this scenario was classified into five values. Unsuitable areas represent 51.18% of the study area, least suitable 16.67%, low suitable 22.85%, suitable 8.61%, and high suitable 0.68%. The best area for locating development projects is the area surrounding El-Tor City and close to the coast. This area could be an urban extension of El-Tor City with more economical and environmental management.

  1. Land Surface Temperature Retrieval from MODIS Data by Integrating Regression Models and the Genetic Algorithm in an Arid Region

    Directory of Open Access Journals (Sweden)

    Ji Zhou

    2014-06-01

    Full Text Available The land surface temperature (LST is one of the most important parameters of surface-atmosphere interactions. Methods for retrieving LSTs from satellite remote sensing data are beneficial for modeling hydrological, ecological, agricultural and meteorological processes on Earth’s surface. Many split-window (SW algorithms, which can be applied to satellite sensors with two adjacent thermal channels located in the atmospheric window between 10 μm and 12 μm, require auxiliary atmospheric parameters (e.g., water vapor content. In this research, the Heihe River basin, which is one of the most arid regions in China, is selected as the study area. The Moderate-resolution Imaging Spectroradiometer (MODIS is selected as a test case. The Global Data Assimilation System (GDAS atmospheric profiles of the study area are used to generate the training dataset through radiative transfer simulation. Significant correlations between the atmospheric upwelling radiance in MODIS channel 31 and the other three atmospheric parameters, including the transmittance in channel 31 and the transmittance and upwelling radiance in channel 32, are trained based on the simulation dataset and formulated with three regression models. Next, the genetic algorithm is used to estimate the LST. Validations of the RM-GA method are based on the simulation dataset generated from in situ measured radiosonde profiles and GDAS atmospheric profiles, the in situ measured LSTs, and a pair of daytime and nighttime MOD11A1 products in the study area. The results demonstrate that RM-GA has a good ability to estimate the LSTs directly from the MODIS data without any auxiliary atmospheric parameters. Although this research is for local application in the Heihe River basin, the findings and proposed method can easily be extended to other satellite sensors and regions with arid climates and high elevations.

  2. GRACE Gravity Satellite Observations of Terrestrial Water Storage Changes for Drought Characterization in the Arid Land of Northwestern China

    Directory of Open Access Journals (Sweden)

    Yanping Cao

    2015-01-01

    Full Text Available Drought is a complex natural hazard which can have negative effects on agriculture, economy, and human life. In this paper, the primary goal is to explore the application of the Gravity Recovery and Climate Experiment (GRACE gravity satellite data for the quantitative investigation of the recent drought dynamic over the arid land of northwestern China, a region with scarce hydrological and meteorological observation datasets. The spatiotemporal characteristics of terrestrial water storage changes (TWSC were first evaluated based on the GRACE satellite data, and then validated against hydrological model simulations and precipitation data. A drought index, the total storage deficit index (TSDI, was derived on the basis of GRACE-recovered TWSC. The spatiotemporal distributions of drought events from 2003 to 2012 in the study region were obtained using the GRACE-derived TSDI. Results derived from TSDI time series indicated that, apart from four short-term (three months drought events, the study region experienced a severe long-term drought from May 2008 to December 2009. As shown in the spatial distribution of TSDI-derived drought conditions, this long-term drought mainly concentrated in the northwestern area of the entire region, where the terrestrial water storage was in heavy deficit. These drought characteristics, which were detected by TSDI, were consistent with local news reports and other researchers’ results. Furthermore, a comparison between TSDI and Standardized Precipitation Index (SPI implied that GRACE TSDI was a more reliable integrated drought indicator (monitoring agricultural and hydrological drought in terms of considering total terrestrial water storages for large regions. The GRACE-derived TSDI can therefore be used to characterize and monitor large-scale droughts in the arid regions, being of special value for areas with scarce observations.

  3. Soil moisture variability and land use in a seasonally arid environment

    Science.gov (United States)

    Williams, A. G.; Ternan, J. L.; Fitzjohn, C.; de Alba, S.; Perez-Gonzalez, A.

    2003-02-01

    Soil moisture patterns were recorded for six different land uses, including oak forest, matorral scrub, olives, and a cultivated field, in central Spain during 1998-99. Volumetric water content was determined using time domain reflectometry at more than 140 sites in each, extending across a range of topographic units. Soil moisture content was a function of land use, with the oak forest being wetter than either the matorral shrubby area or the cultivated site. The spatial patterns for a wet period were kriged and are presented as interpolated contour plots. Geo-statistical analysis confirmed that the patterns were highly heterogeneous, as the variograms showed a pure nugget for each land use, except for the two olive sites, where some spatial structure could be observed. During the investigation the soils were in the dry state and the soil moisture distribution was controlled by local factors; it was not possible to determine which environmental factor had the most influence.

  4. Stress resistance strategy in an arid land shrub: interactions between developmental instability and fractal dimention

    Science.gov (United States)

    Escos, J.; Alados, C.L.; Pugnaire, F. I.; Puigdefábregas, J.; Emlen, J.

    2000-01-01

    This paper investigates allocation of energy to mechanisms that generate and preserve architectural forms (i.e. developmental stability, complexity of branching patterns) and productivity (growth and reproduction) in response to environmental disturbances (i.e. grazing and resource availability). The statistical error in translational symmetry was used to detect random intra-individual variability during development. This can be thought of as a measure of developmental instability caused by stress. Additionally, we use changes in fractal complexity and shoot distribution of branch structures as an alternate indicator of stress. These methods were applied to Anthyllis cytisoides L., a semi-arid environment shrub, to ascertain the effect of grazing and slope exposure on developmental traits in a 2×2 factorial design. The results show that A. cytisoidesmaintains developmental stability at the expense of productivity. Anthyllis cytisoides was developmentally more stable when grazed and when on south-facing, as opposed to north-facing slopes. On the contrary, shoot length, leaf area, fractal dimension and reproductive-to-vegetative allocation ratio were larger in north- than in south-facing slopes. As a consequence, under extreme xeric conditions, shrub mortality increased in north-facing slopes, especially when not grazed. The removal of transpiring area and the reduction of plant competition favoured developmental stability and survival in grazed plants. Differences between grazed and ungrazed plants were most evident in more mesic (north-facing) areas.

  5. Social-biophysical feedbacks and land change in an arid rangeland region

    Science.gov (United States)

    Studies of human-dominated ecosystems have traditionally externalized human agents and their behavior. Rangelands of the southwestern U.S. are no exception: in spite of century-long studies of vegetation change, the specific role of human decisions and their feedbacks with land condition are unknown...

  6. Land-surface and boundary layer processes in a semi-arid heterogeneous landscape

    NARCIS (Netherlands)

    Jochum, A.M.

    2003-01-01

    The European Field Experiment in a Desertification-threatened Area (EFEDA) provides a comprehensive land-surface dataset for a semiarid Mediterranean environment. It is used here to study heat and moisture transport processes in the atmospheric boundary layer (ABL), to derive grid-scale surface flux

  7. Estimation of water requirement per unit carbon fixed by Eucalyptus camaldulensis in semi-arid land of Western Australia

    Institute of Scientific and Technical Information of China (English)

    T. Kojima; Y. Tanaka; S. Katoh; K. Tahara; N. Takahashi; K, Yamada

    2002-01-01

    Afforestation in arid land is a promising method for carbon fixation, but the effective utili-zation of water is highly important and required. Thus, the evaluation of the amount of water perunit carbon fixed with the tree growth is required to minimize the amount of water supplied to theplants. In this research, a tree is regarded as a carbon fixation reactor with inflows of water andnutrients from roots, and CO2 as the carbon source from leaves with outflow of water vapor fromleaves and accumulation in the tree itself. In the process of photosynthesis and respiration nutri-tional elements are dissolved in water flow in trees. They do not flow out by these reactions, butare accumulated in trees. Thus, we have treated the behaviour of nutrients as a marker to evaluatethe water/carbon ratio. Assuming that nutrient concentration is constant in sap, and the differences in the ratios ofnutrient to carbon in living trees and dead (i.e. litter fall, etc.) are negiected, the ratio of the usedwater to fixed carbon is given as the ratio of nutrient to carbon in the tree body divided by the ratioof nutrient to water in sap. However, some nutrients are translocated and concentrated within thetree and some may be discarded through litter fall. Thus it is important to examine which nutrientelement is the most suitable as the tracer. In this paper, the results of the above method applied to Eucalyptus camaldulensis in semi-arid land of Western Australia are shown. The value of water requirement per unit carbon fixationdetermined from potassium balance is between 421 kg-H2O/kg-C for mature trees and 285kg-H2O/k9-C for young trees, while the values from calcium balance are much larger than these.The cause of the discrepancy between these values is discussed based on the measured elementconcentrations in sap and trees and the plant physiology. Finally, the actual average value throughthe life of a tree is suggested to fall between the two values.

  8. Geomorphic changes leading to natural desertification versus anthropogenic land conservation in an arid environment, the Negev Highlands, Israel

    Science.gov (United States)

    Avni, Yoav; Porat, Naomi; Plakht, Joseph; Avni, Gideon

    2006-12-01

    onto natural desertification of the region. The historical intervention by establishment of runoff-harvesting agriculture, which as a by-product resulted in the accumulation of redeposited loess sediments, counteracted the natural trend of soil erosion. This was in fact a land-conservation act, applied by the ancient farmers in the semi-arid regions of the Middle East deserts. This activity and its geomorphic consequences are in contrast to the well-documented land degradation trend generated by recent anthropogenic impact on marginal lands elsewhere. In any case, the human impact, either contributing to land degradation or to soil conservation, is super-imposed on the natural long-term trend leading toward desertification.

  9. Soil Moisture Mapping in an Arid Area Using a Land Unit Area (LUA Sampling Approach and Geostatistical Interpolation Techniques

    Directory of Open Access Journals (Sweden)

    Saeid Gharechelou

    2016-03-01

    Full Text Available Soil moisture (SM plays a key role in many environmental processes and has a high spatial and temporal variability. Collecting sample SM data through field surveys (e.g., for validation of remote sensing-derived products can be very expensive and time consuming if a study area is large, and producing accurate SM maps from the sample point data is a difficult task as well. In this study, geospatial processing techniques are used to combine several geo-environmental layers relevant to SM (soil, geology, rainfall, land cover, etc. into a land unit area (LUA map, which delineates regions with relatively homogeneous geological/geomorphological, land use/land cover, and climate characteristics. This LUA map is used to guide the collection of sample SM data in the field, and the field data is finally spatially interpolated to create a wall-to-wall map of SM in the study area (Garmsar, Iran. The main goal of this research is to create a SM map in an arid area, using a land unit area (LUA approach to obtain the most appropriate sample locations for collecting SM field data. Several environmental GIS layers, which have an impact on SM, were combined to generate a LUA map, and then field surveying was done in each class of the LUA map. A SM map was produced based on LUA, remote sensing data indexes, and spatial interpolation of the field survey sample data. The several interpolation methods (inverse distance weighting, kriging, and co-kriging were evaluated for generating SM maps from the sample data. The produced maps were compared to each other and validated using ground truth data. The results show that the LUA approach is a reasonable method to create the homogenous field to introduce a representative sample for field soil surveying. The geostatistical SM map achieved adequate accuracy; however, trend analysis and distribution of the soil sample point locations within the LUA types should be further investigated to achieve even better results. Co

  10. Policies, Land Use, and Water Resource Management in an Arid Oasis Ecosystem

    Science.gov (United States)

    Xue, Xian; Liao, Jie; Hsing, Youtian; Huang, Cuihua; Liu, Famin

    2015-05-01

    This paper addresses two questions concerning the relationship between state policies and environmental transformation in China in the past four decades. The first one deals with the promotion of agricultural productivity since the 1980s; the second, the water conservation measures as a response to the water crisis that peaked in the early 2000s. We had chosen Minqin County in northwestern China, one of the most fragile arid oasis systems in the world, as the study area. We found that the irrigated farmland in up and midstream areas had greatly expanded between the 1980s and the 2000s under the government policy of promoting commodity grain production. As a result, the runoff flowing into Minqin Oasis had reduced 80 % from the 1950s to early 2000s. Irrigated farmland in Minqin Oasis expanded 15.76 % from 1995 to 2000. In the 2000s, because of the changing policy discourse that has shifted from productivity to conservation, a new set of environmentally framed policies has restructured agricultural production in Minqin by 2005. These new policies included establishing a watershed-level water management system, promoting drought resistant crops, introducing water-saving irrigation measures, and forced reduction of irrigated farming acreage. These policies have produced positive results in terms of greater coverage of vegetation, rising ground water table, and reduction of evaporation. Nevertheless, new policies have also brought new challenges to both farmers and policy makers to keep the balance between poverty reduction and environmental sustainability in Minqin Oasis in the historically poor region in China's Northwest.

  11. Modeling Soil Moisture in Support of the Revegetation of Military Lands in Arid Regions.

    Science.gov (United States)

    Caldwell, T. G.; McDonald, E. V.; Young, M. H.

    2003-12-01

    The National Training Center (NTC), the Army's primary mechanized maneuver training facility, covers approximately 2600 km2 within the Mojave Desert in southern California, and is the subject of ongoing studies to support the sustainability of military lands in desert environments. Revegetation of these lands by the Integrated Training Areas Management (ITAM) Program requires the identification of optimum growing conditions to reestablish desert vegetation from seed and seedling, especially with regard to the timing and abundance of plant-available water. Water content, soil water potential, and soil temperature were continuously monitored and used to calibrate the Simultaneous Heat And Water (SHAW) model at 3 re-seeded sites. Modeled irrigation scenarios were used to further evaluate the most effective volume, frequency, and timing of irrigation required to maximize revegetation success and minimize water use. Surface treatments including straw mulch, gravel mulch, soil tackifier and plastic sheet

  12. Ecological soil quality affected by land use and management on semi-arid Crete

    Science.gov (United States)

    van Leeuwen, J. P.; Moraetis, D.; Lair, G. J.; Bloem, J.; Nikolaidis, N. P.; Hemerik, L.; de Ruiter, P. C.

    2015-03-01

    Land use and soil management practice can have strong effects on soil quality, defined in terms of soil fertility, carbon sequestration and conservation of biodiversity. In this study, we investigate whether ecological soil quality parameters are adequate to assess soil quality under harsh conditions, and are able to reflect different land uses and intensities of soil management practices. We selected three sites as main representatives for the dominant types of land use in the region: an intensively cultivated olive orchard (annually tilled), an extensively used olive orchard (not tilled) and a heavily grazed pasture site in the Koiliaris catchment (Crete/Greece). Soil quality was analysed using an ecosystem approach, studying soil biological properties such as soil organism biomass and activity, and taxonomic diversity of soil microarthropods, in connection to abiotic soil parameters, including soil organic matter contents, and soil aggregate stability. The intensively cultivated olive orchard had a much lower aggregate water stability than the extensive olive orchard and the pasture. Contents of soil organic C and N were higher in the extensively used olive orchard than in the intensively cultivated orchard, with intermediate concentrations in the pasture. This was mainly caused by the highest input of organic matter, combined with the lowest organic matter decomposition rate. Soil organism biomasses in all sites were relatively low compared to values reported from less harsh systems, while microarthropod richness was highest in the pasture compared to both the intensive and extensive olive orchards. From the present results we conclude that microarthropod taxonomic richness is a very useful indicator for ecological soil quality, because it is not only able to separate harsh sites from other systems, but it is also sensitive enough to show differences between land management practices under harsh conditions. Microbial biomass and especially microarthropod

  13. On the operationalization of a spatially explicit evaluation of the complexity of land use trajectories in semi-arid Mediterranean agro-ecosystems

    DEFF Research Database (Denmark)

    Nainggolan, Doan

    of the interacting effects of various types of drivers. The thesis highlights conceptual and practical challenges in undertaking an integrated evaluation of land use change complexity. Future policy making should consider the various factors that are jointly shaping agricultural land use trajectories.......This thesis aims to unpack the complexity of trajectories of land use change in semi-arid Mediterranean agro-ecosystems – illustrated using findings from the Torrealvilla catchment in south-eastern Spain. The research looks at multiple dimensions of land use change and addresses the past, present...... for further expansion of irrigated farming, the agent-based scenario analysis indicates the opposite. Overall the thesis confirms that land use changes in Mediterranean agro-ecosystems are indeed complex entailing multiple, contrasting, and perhaps competing trajectories and are the manifestation...

  14. Habitat Fragmentation in Arid Zones: A Case Study of Linaria nigricans Under Land Use Changes (SE Spain)

    Science.gov (United States)

    Peñas, Julio; Benito, Blas; Lorite, Juan; Ballesteros, Miguel; Cañadas, Eva María; Martinez-Ortega, Montserrat

    2011-07-01

    Habitat fragmentation due to human activities is one of the most important causes of biodiversity loss. In Mediterranean areas the species have co-evolved with traditional farming, which has recently been replaced for more severe and aggressive practices. We use a methodological approach that enables the evaluation of the impact that agriculture and land use changes have for the conservation of sensitive species. As model species, we selected Linaria nigricans, a critically endangered plant from arid and semiarid ecosystems in south-eastern Spain. A chronosequence of the evolution of the suitable habitat for the species over more than 50 years has been reconstructed and several geometrical fragmentation indices have been calculated. A new index called fragmentation cadence (FC) is proposed to quantify the historical evolution of habitat fragmentation regardless of the habitat size. The application of this index has provided objective forecasting of the changes of each remnant population of L. nigricans. The results indicate that greenhouses and construction activities (mainly for tourist purposes) exert a strong impact on the populations of this endangered species. The habitat depletion showed peaks that constitute the destruction of 85% of the initial area in only 20 years for some populations of L. nigricans. According to the forecast established by the model, a rapid extinction could take place and some populations may disappear as early as the year 2030. Fragmentation-cadence analysis can help identify population units of primary concern for its conservation, by means of the adoption of improved management and regulatory measures.

  15. Survey of Revegetated Areas on the Fitzner/Eberhardt Arid Lands Ecology Reserve: Status and Initial Monitoring Results

    Energy Technology Data Exchange (ETDEWEB)

    Downs, Janelle L.; Link, Steven O.; Rozeboom, Latricia L.; Durham, Robin E.; Cruz, Rico O.; Mckee, Sadie A.

    2011-09-01

    During 2010, the U.S. Department of Energy (DOE), Richland Operations Office removed a number of facilities and debris from the Fitzner/Eberhardt Arid Lands Ecology Reserve (ALE), which is part of the Hanford Reach National Monument (HRNM). Revegetation of disturbed sites is necessary to stabilize the soil, reduce invasion of these areas by exotic weeds, and to accelerate re-establishment of native plant communities. Seven revegetation units were identified on ALE based on soils and potential native plant communities at the site. Native seed mixes and plant material were identified for each area based on the desired plant community. Revegetation of locations affected by decommissioning of buildings and debris removal was undertaken during the winter and early spring of 2010 and 2011, respectively. This report describes both the details of planting and seeding for each of the units, describes the sampling design for monitoring, and summarizes the data collected during the first year of monitoring. In general, the revegetation efforts were successful in establishing native bunchgrasses and shrubs on most of the sites within the 7 revegetation units. Invasion of the revegetation areas by exotic annual species was minimal for most sites, but was above initial criteria in 3 areas: the Hodges Well subunit of Unit 2, and Units 6 and 7.

  16. 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

  17. 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.

  18. Screening Prosopis (mesquite) species for biofuel production on semi-arid lands. Final report, April 1, 1978-March 30, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Felker, P; Cannell, G H; Clark, P R; Osborn, J F; Nash, P

    1985-01-01

    Arid adapted nitrogen fixing trees and shrubs of the genus Prosopis (mesquite) have been examined for woody biomass production on semi-arid lands of southwestern United States. A germ-plasm collection of 900 accessions from North and South America and Africa was assembled. Field studies screening for biomass production, frost tolerance, response to irrigation, pod production and heat/drought tolerance involved a total of 80 accessions. Selections made from survivors of coal/frost screening trial had more frost tolerance and biomass productivity than prostrate selections from the ranges of Arizona, New Mexico and west Texas. Thirteen Prosopis species were found to nodulate, reduce acetylene to ethylene, and grow on a nitrogen free media in greenhouse experiments. The salinity tolerance of six Prosopis species was examined on a nitrogen free media in greenhouse experiments. No reduction in growth occurred for any species tested at a salinity of 6000 mg NaC1/L which is considered too saline for normal agricultural crops. Individual trees have grown 5 to 7 cm in basal diameter, and 2.0 to 3.7 meters in height per year and have achieved 50 kg oven dry weight per tree in 2 years with 600 mm water application per year. Vegetative propagation techniques have been developed and clones of these highly productive trees have been made. Small pilots on 1.5 x 1.5 m spacing in the California Imperial Valley had a first and second season dry matter production of 11.7 and 16.9 T/ha for P. chilensis (0009), 7.1 and 6.9 T/ha for P. glandulosa var. torreyana (0001), 9.8 and 19.2 T/ha for P. alba (0039) and 7.9 and 14.5 T/ha for progency of a California ornamental (0163). The projected harvested costs of $25.00 per oven dry ton or $1.50 per million Btu's compare favorable with coal and other alternative fuel sources in South Texas.

  19. Novel ideas for maximising dew collection to aid plant establishment to combat desertification and restore degraded dry and arid lands

    Science.gov (United States)

    Kotzen, Benz

    2014-05-01

    This paper focuses on the potential of dew to provide water to plants and potentially to people as well in remote and difficult to reach areas where rainfall and underground water cannot be harvested. The combat of desertification and the restoration of degraded and desertified dry and arid lands has never been more urgent. A key practical component of this strategy is the restoration of habitat with planting. But for habitat and planting to survive there needs to be an adequate supply of water. In most cases providing water to the plant's roots is vital. In some areas where habitats have been destroyed, sufficient water is immediately available, for example through seasonal rainfall, or it can be harvested to concentrate adequate supplies of water to the roots. However, in arid and hyper arid areas, as well as in some dryland areas, a consistent and adequate supply of water cannot be provided by any conventional proven method. Thus, as the need to combat desertification and to restore desertified dry and arid land increases, so the need to find novel methods of establishing and maintaining planting and thus habitat increases. In more traditional land management scenarios this can be achieved through manipulating landform on a micro and macro scale, for example, by creating catchments, thereby collecting precipitation and directing it to the plants. Where this cannot be done, other means of water supply are usually required. Bainbridge (2007) and others have shown that supplying water to plants is possible through a number of traditional methods, for example, using clay pots. But most of these techniques require an introduced source of water, for example, obtained through water harvesting methods or by delivering water to site in tanks and by water bowser. This can work but requires continuous manpower. It is expensive and can be physically prohibitive in areas where access is difficult and/or remote. The concept of using dew to supply water in drylands is not new

  20. Bacterial community structure and nitrogen transformation in hyporheic zones of arid-land streams

    Science.gov (United States)

    Zeglin, L. H.; Crenshaw, C. L.; Dahm, C. N.; Takacs-Vesbach, C.

    2007-12-01

    Hyporheic zones of desert streams can be areas of high biological activity and consequent nutrient transformation, particularly where land use change increases nutrient concentrations in a stream. Does hyporheic bacterial community composition vary, and does this biotic heterogeneity covary with water and nutrient supply? Bromide (Br-) and 15N-NO3- was injected for 24 hr in six streams (three "natural" reference streams, three streams in agricultural/urbanized catchments) in New Mexico and Arizona, USA. Four transects of 3 to 4 wells were placed along a longitudinal gradient within the study reach, and from these hyporheic water and gas samples were collected during and after each experiment. Gas samples were analyzed for O2, 15N2O, and 15N2. Hyporheic water samples were analyzed for major cations and anions, DOC, 15NO3- and 15NH4+. Bacterial diversity of hyporheic water was assessed using Denaturing Gradient Gel Electrophoresis (DGGE). There was high spatial and temporal variability in hyporheic bacterial community structure, connection with surface water and nutrient concentrations both within and among streams. For example, mean subsurface DGGE band richness per stream ranged from 9 to 21, and surface water comprised between 0 to 100 percent of hyporheic water in each well. There were strong differences in bacterial richness between streams (ANOVA, p nutrient concentration. 15NH4+ levels were higher in modified stream than reference stream subsurface waters, suggesting dissimilatory nitrate reduction to ammonium (DNRA) may be an important process in these hyporheic sediments. Our results to date suggest that though hyporheic microbial community structure is highly heterogeneous, this biological variability may be due to different factors than variability in stream nitrogen cycling function. Further work will identify dominant sequences within these bacterial communities and investigate within-stream heterogeneity.

  1. Changes in Lipids Utilisation During Moisture and Temperature Stress of Infective (L3 and its Implication on the Epidemiology of Haemonchus contortus in Arid and Semi Arid Lands

    Directory of Open Access Journals (Sweden)

    D.N. Siamba

    2011-03-01

    Full Text Available A study was undertaken to establish the pattern and level of lipid utilization in third stage infective larvae (L3 of Haemonchus contortus under temperature and moisture stress conditions. The stress factors were representative of an arid and semi arid site in Kenya. The L3 were subjected to gradual increase and reduction in temperature and moisture, respectively, using a programmable cold/heat testing chamber. Optical density per area (Corrected average pixels derived from image analysis of individual stained larvae using an image analysis software (UN SCAN IT gel(r, were used to estimate the lipid content of larvae subjected to different stress treatments. It was observed that lipid content of the L3 declined and was negatively correlated with duration of exposure with significantly (p = 0.012 lower rates in moisture compared to temperature stressed L3. It was also observed that the decline occurred in phases signifying possible adaptive physiological process aimed at preserving lipid reserves and viability. During revival, there was a drastic decline in lipid reserves probably as a result of increased lipid utilisation by the reviving larvae. The epidemiological significance of these findings in field larvae is discussed.

  2. Evaluation of Land Surface Temperature Retrieval from FY-3B/VIRR Data in an Arid Area of Northwestern China

    Directory of Open Access Journals (Sweden)

    Jinxiong Jiang

    2015-05-01

    Full Text Available This paper uses the refined Generalized Split-Window (GSW algorithm to derive the land surface temperature (LST from the data acquired by the Visible and Infrared Radiometer on FengYun 3B (FY-3B/VIRR. The coefficients in the GSW algorithm corresponding to a series of overlapping ranges for the mean emissivity, the atmospheric Water Vapor Content (WVC, and the LST are derived using a statistical regression method from the numerical values simulated with an accurate atmospheric radiative transfer model MODTRAN 4 over a wide range of atmospheric and surface conditions. The GSW algorithm is applied to retrieve LST from FY-3B/VIRR data in an arid area in northwestern China. Three emissivity databases are used to evaluate the accuracy of different emissivity databases for LST retrieval, including the ASTER Global Emissivity Database (ASTER_GED at a 1-km spatial resolution (AG1km, an average of twelve ASTER emissivity data in the 2012 summer and emissivity spectra extracted from spectral libraries. The LSTs retrieved from the three emissivity databases are evaluated with ground-measured LST at four barren surface sites from June 2012 to December 2013 collected during the HiWATER field campaign. The results indicate that using emissivity extracted from ASTER_GED can achieve the highest accuracy with an average bias of 1.26 and −0.04 K and an average root mean square error (RMSE of 2.69 and 1.38 K for the four sites during daytime and nighttime, respectively. This result indicates that ASTER_GED is a useful emissivity database for generating global LST products from different thermal infrared data and that using FY-3B/VIRR data can produce reliable LST products for other research areas.

  3. Modelling ecogeomorphic feedbacks: investigating mechanisms of land degradation in semi-arid grassland and shrubland

    Science.gov (United States)

    Turnbull, Laura; Mueller, Eva; Tietjen, Britta; Wainwright, John

    2014-05-01

    Across vast areas of the world's drylands, land degradation is exacerbated by ecohydrological processes, which alter the structure, function and connectivity of dryland hillslopes. These processes are often interlinked through feedback mechanisms in such a way that a trigger may result in a re-organization of the affected landscape. Here, we present a spatially explicit process-based ecogeomorphic model, MAHLERAN-EcoHyD to enhance our understanding of complex linkages between abiotic and biotic drivers and processes of degradation in drylands. This ecogeomorphic modelling approach is innovative in two main ways: it couples biotic and abiotic processes, and simulates intra and inter-event dynamics, thus overcoming a key limitation of previous modelling approaches in terms of their temporal scaling, by simulating key ecogeomorphic processes at process-relevant time steps. Redistribution of water, sediment and nutrients during high-intensity rainstorms is simulated at 1-sec time steps, soil moisture and transpiration dynamics at daily time steps, and vegetation dynamics (establishment, growth, mortality) at 14-day time steps, over a high-resolution 1x1 m grid. We use this innovative modelling approach to investigate soil-vegetation feedback mechanisms within a grassland-shrubland transition zone at the Sevilleta Long Term Ecological Research site in the south-western United States. Results from three modelling experiments are presented: the first modelling experiment investigates the impact of annual variations in individual high-intensity storms to assess long-term variations in runoff, soil-moisture conditions and sediment and nutrient fluxes over two decades; the second modelling experiment assesses the impact of vegetation composition on spatial changes in surface soil texture due to soil erosion by water; and the third modelling experiment investigates how long-term changes in vegetation alter feedbacks between biotic and abiotic processes using scenarios for

  4. Water, land, climate change and agrarian livelihood in an arid region riparian corridor: Rayón, Sonora, Mexico

    Science.gov (United States)

    Lee, R.; Scott, C. A.; Curl, K.; House-Peters, L.; Buechler, S.

    2012-12-01

    Results of recent fieldwork in Rayón, Sonora, Mexico (funded by NSF's "Strengthening Resilience of Arid Region Riparian Corridors") indicate that the coupled natural and human (CNH) system that has persisted since the town's founding in 1626 is being degraded and destabilised by a confluence of social and ecological pressures. System change or loss of key system services and products has important implications for ecological services and human economic activity in the riparian corridor. Less water quantity is the primary factor responsible for driving system degradation and change. Drought caused by climate change is widely perceived by agriculturists as responsible for reduced water quantity in the riparian area. Reductions in water quantity are so severe that the once perennial Rio San Miguel did not run during 2012's summer months for the first time in residents' memory. Ninety-percent of wells are dry. Fields irrigated by surface-water acequias were not planted. Starvation or dehydration has thinned herd sizes. Residents fear they will lose the ability to practice their traditional livelihoods: ranching, farming and cheese production. Drought conditions and resource management in response to climatic change have had a net negative impact on ecological services. Agriculturists have responded to less forage and pasture for cattle by clearing mesquite forests, putting land into production, and increasing water demand. From interviews it appears this process is cyclical: agriculturists widely believe access to more water or an end to the drought are the only ways to improve conditions. Interviews also reveal (a) agriculturists view technology, especially that which is able to improve water-use efficiency, as means to reduce stress in the CNH system and (b) a holistic view that couples natural well-being to human well-being is absent from the majority of respondents' worldviews. Technological and adoption of holistic perceptions are adaptations that may potentially

  5. 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....

  6. 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.

  7. Shifts in Abundance and Diversity of Soil Ammonia-Oxidizing Bacteria and Archaea Associated with Land Restoration in a Semi-Arid Ecosystem.

    Directory of Open Access Journals (Sweden)

    Zhu Chen

    Full Text Available The Grain to Green Project (GGP is an unprecedented land restoration action in China. The project converted large areas (ca 10 million ha of steep-sloped/degraded farmland and barren land into forest and grassland resulting in ecological benefits such as a reduction in severe soil erosion. It may also affect soil microorganisms involved in ammonia oxidization, which is a key step in the global nitrogen cycle. The methods for restoration that are typically adopted in semi-arid regions include abandoning farmland and growing drought tolerant grass (Lolium perenne L. or shrubs (Caragana korshinskii Kom.. In the present study, the effects of these methods on the abundance and diversity of ammonia-oxidizing bacteria (AOB and ammonia-oxidizing archaea (AOA were evaluated via quantitative real-time PCR, terminal restriction fragment length polymorphism and clone library analysis of amoA genes. Comparisons were made between soil samples from three restored lands and the adjacent farmland in Inner Mongolia. Both the abundance and community composition of AOB were significantly different between the restored lands and the adjacent control. Significantly lower nitrification activity was observed for the restored land. Clone library analysis revealed that all AOB amoA gene sequences were affiliated with Nitrosospira. Abundance of the populations that were associated with Nitrosospira sp. Nv6 which had possibly adapted to high concentrations of inorganic nitrogen, decreased on the restored land. Only a slight difference in the AOB communities was observed between the restored land with and without the shrub (Caragana korshinskii Kom.. A minor effect of land restoration on AOA was observed. In summary, land restoration negatively affected the abundance of AOB and soil nitrification activities, suggesting the potential role of GGP in the leaching of nitrates, and in the emission of N2O in related terrestrial ecosystems.

  8. 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

  9. Fractal Characteristics of Soil under Different Land-Use Patterns in the Arid and Semi-Arid Region of the Western Tibet Plateau, China

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-dan; LIU Shu-zhen; LIU Gang-cai

    2005-01-01

    The fractal geometry to the study of soil structure, its dynamics, and physical processes appears to be a useful tool in reaching a better understanding of system performance. This research was designed to apply fractal models for mass into computing Dp and Da values. As a result, the relationships among land use methods, fractal dimension and soil fertility have been discussed. The study conclusions include that (i) fractal dimension indicates not only characteristics of soil texture but also effects of natural environment changes and human activities on soil properties, (ii) soil fertility is best when Dp <2.65 and Da <2.44, (iii) maximal values of Dp under all land use patterns are equal and appear in the range the depth of 15-20 cm in the study area, but maximal values of Da are different and distribute in various profile depth. These results can provide an important support to understand soil properties in plateau soil-forming environment, and be helpful to conduct scientific soil tillage and management.

  10. Land use change and its effects on water quality in typical inland lake of arid area in China.

    Science.gov (United States)

    Cui, Hong; Zhou, Xiaode; Guo, Mengjing; Wei, Wu

    2016-07-01

    Land-use change is very important for determining and assessing the influence of human activity on aquatic environment of rivers and lakes. The present work with Bosten River basin as the subject, analyzes features of dynamic land-use change of the basin from 1993 to 2013, in order to study the influence of land-use pattern change on the basin water quality, according to the land-use/land-cover(LUCC) chart from 2000 to 2013 made by ArcGIS and ENVI. It shows cultivated land, wetland and forestland constitute most of Bosten River basin, taking up over 41.7% of the total; from 1993-2000, LUCC of the basin is relatively small, with an increase of cultivated land, residential-industry land, water wetlands by 15.09%-18.33%,most of which are transformed from forestland, grassland and unused land; from 2000-2013, LUCC of the basin is relatively significant, with a continuing and bigger increase of cultivated land and Residential-industry area, most of which are transformed from water wetlands and unused land. Based on analysis of landuse pattern and water quality index, it can be told that water pollution is positively correlated to cultivated land and residential-industry area and negatively correlated to water and grassland. Also, the influence of land-use pattern change on water quality has been discussed, whose finding can serve as the scientific evidence for land-use optimization and water pollution control. PMID:27498508

  11. Land use change and its effects on water quality in typical inland lake of arid area in China.

    Science.gov (United States)

    Cui, Hong; Zhou, Xiaode; Guo, Mengjing; Wei, Wu

    2016-07-01

    Land-use change is very important for determining and assessing the influence of human activity on aquatic environment of rivers and lakes. The present work with Bosten River basin as the subject, analyzes features of dynamic land-use change of the basin from 1993 to 2013, in order to study the influence of land-use pattern change on the basin water quality, according to the land-use/land-cover(LUCC) chart from 2000 to 2013 made by ArcGIS and ENVI. It shows cultivated land, wetland and forestland constitute most of Bosten River basin, taking up over 41.7% of the total; from 1993-2000, LUCC of the basin is relatively small, with an increase of cultivated land, residential-industry land, water wetlands by 15.09%-18.33%,most of which are transformed from forestland, grassland and unused land; from 2000-2013, LUCC of the basin is relatively significant, with a continuing and bigger increase of cultivated land and Residential-industry area, most of which are transformed from water wetlands and unused land. Based on analysis of landuse pattern and water quality index, it can be told that water pollution is positively correlated to cultivated land and residential-industry area and negatively correlated to water and grassland. Also, the influence of land-use pattern change on water quality has been discussed, whose finding can serve as the scientific evidence for land-use optimization and water pollution control.

  12. Assessing the biophysical and socio-economic potential of Sustainable Land Management and Water Harvesting Technologies for rainfed agriculture across semi-arid Africa.

    Science.gov (United States)

    Irvine, Brian; Fleskens, Luuk; Kirkby, Mike

    2016-04-01

    Stakeholders in recent EU projects identified soil erosion as the most frequent driver of land degradation in semi-arid environments. In a number of sites, historic land management and rainfall variability are recognised as contributing to the serious environmental impact. In order to consider the potential of sustainable land management and water harvesting techniques stakeholders and study sites from the projects selected and trialled both local technologies and promising technologies reported from other sites . The combined PESERA and DESMICE modelling approach considered the regional effects of the technologies in combating desertification both in environmental and socio-economical terms. Initial analysis was based on long term average climate data with the model run to equilibrium. Current analysis, primarily based on the WAHARA study sites considers rainfall variability more explicitly in time series mode. The PESERA-DESMICE approach considers the difference between a baseline scenario and a (water harvesting) technology scenario, typically, in terms of productivity, financial viability and scope for reducing erosion risk. A series of 50 year rainfall realisations are generated from observed data to capture a full range of the climatic variability. Each realisation provides a unique time-series of rainfall and through modelling can provide a simulated time-series of crop yield and erosion risk for both baseline conditions and technology scenarios. Subsequent realisations and model simulations add to an envelope of the potential crop yield and cost-benefit relations. The development of such envelopes helps express the agricultural and erosional risk associated with climate variability and the potential for conservation measures to absorb the risk, highlighting the probability of achieving a given crop yield or erosion limit. Information that can directly inform or influence the local adoption of conservation measures under the climatic variability in semi-arid

  13. Project 5322 Mid-Term Report: Key Eco-Hydrological Parameters Retrieval And Land Data Assimilation System Development In A Typical Inland River Basin Of Chinas Arid Region

    Science.gov (United States)

    Faivre, R.; Colin, J.; Menenti, M.; Lindenbergh, R.; Van Den Bergh, L.; Yu, H.; Jia, L.; Xin, L.

    2010-10-01

    Improving the understanding and the monitoring of high elevation regions hydrology is of major relevance from both societal and environmental points of view for many Asian countries, in particular in terms of flood and drought, but also in terms of food security in a chang- ing environment. Satellite and airborne remote sensing technologies are of utmost for such a challenge. Exist- ing imaging spectro-radiometers, radars, microwave ra- diometers and backscatter LIDAR provide a very com- prehensive suite of measurements over a wide rage of wavelengths, time frequencies and spatial resolu- tions. It is however needed to devise new algorithms to convert these radiometric measurements into useful eco-hydrological quantitative parameters for hydrologi- cal modeling and water management. The DRAGON II project entitled Key Eco-Hydrological Parameters Re- trieval and Land Data Assimilation System Development in a Typical Inland River Basin of Chinas Arid Region (ID 5322) aims at improving the monitoring, understand- ing, and predictability of hydrological and ecological pro- cesses at catchment scale, and promote the applicability of quantitative remote sensing in watershed science. Ex- isting Earth Observation platforms provided by the Euro- pean Space Agency as well as prototype airborne systems developed in China - ENVISAT/AATSR, ALOS/PRISM and PALSAR, Airborne LIDAR - are used and combined to retrieve advanced land surface physical properties over high elevation arid regions of China. The existing syn- ergies between this project, the CEOP-AEGIS project (FP7) and the WATER project (CAS) provide incentives for innovative studies. The investigations presented in the following report focus on the development of advanced and innovative methodologies and algorithms to monitor both the state and the trend of key eco-hydrological vari- ables: 3D vegetation properties, land surface evaporation, glacier mass balance and drought indicators.

  14. Estimates of net infiltration in arid basins and potential impacts on recharge and solute flux due to land use and vegetation change

    Science.gov (United States)

    Robertson, Wendy Marie; Sharp, John M.

    2015-03-01

    Human impacts on land use and vegetation in arid basins have, in some regions, altered infiltration, recharge, and groundwater chemistry. However, some modeling approaches currently used do not account for these effects. In the Trans-Pecos region of Texas the presence of modern water, increasing groundwater NO3- concentrations, and vadose zone cores flushed of naturally accumulated solutes belie the notion that basin groundwater is unaffected by overlying land use and vegetation change. Recharge to the Trans-Pecos basins is spatially and temporally variable, and due to human impacts it has likely changed since pre-western settlement time (circa 1850s). By using the INFIL 3.0.1 model, a spatially distributed model of net infiltration, the volume and spatial distribution of net infiltration was examined for two basins, Wild Horse/Michigan Flats and Lobo/Ryan Flats, with model simulations designed to examine the effects of irrigated agriculture and human impacts on vegetation. Model results indicate that recharge to the basins is not limited to mountain-front zones and discrete features (i.e., alluvial channels), rather, irrigation return flow contributes an estimated 6.3 × 107 m3 (408 mm) of net infiltration over 40 yrs and net infiltration on the basin floors could contribute between 7% and 11.5% of annual basin recharge. Model results also indicate that net infiltration may be higher under current vegetation regimes than in pre-western settlement conditions; the removal of thick dense grasslands in INFIL model simulations enhanced net infiltration by 48% or more. Results from distributed models (like INFIL) improve upon scientific understanding of the links between vegetation regime and hydrological processes; this is important for the sustainable management of arid basin aquifers in Texas and elsewhere.

  15. Hydrological and land use control of watershed exports of dissolved organic matter in a large arid river basin in northwestern China

    Science.gov (United States)

    Hu, Yue; Lu, YueHan; Edmonds, Jennifer W.; Liu, Chuankun; Wang, Sai; Das, Oindrila; Liu, Jie; Zheng, Chunmiao

    2016-02-01

    We evaluated variation in dissolved organic matter (DOM) export as a function of hydrology and land use from a large arid river basin in northwestern China. Two soil-derived, humic-like (C1 and C2) and three protein-like fluorescence components (C3, C4, and C5) were identified. During high discharges, river water DOM had higher values of DOC concentration, percent humic fluorescence, and humification index, but lower values of fluorescence index and percent protein fluorescence than found at base flow, suggesting that flow paths shifted to shallower depths flushing out topsoil organic matter. Loading of DOC and soil-derived humic fluorescence were driven largely by discharge, with values over 10 times higher during high discharges than at base flow. Furthermore, both δ13C-DOC and C1 at high flows positively correlated with %agricultural lands within 1 km river buffers, demonstrating that near-river agricultural activities enhanced storm export of soil DOM. At base flow, C4 positively correlated with %agricultural lands, showing stimulation of aquatic bacterial carbon production as a result of elevated nutrient inputs from agricultural lands. Percent contributions of humic fluorescence in groundwater varied with well depths in shallow wells, but this pattern was not observed for deeper groundwater, suggesting that humic DOM could serve as a water source tracer indicating deeper aquifers were isolated from river water and shallow groundwater. Together, our data demonstrate that hydrology and land use controlled the sources and amount of riverine DOM in this large agricultural basin and that regulating storm runoff and near-river agricultural activities should be incorporated in ecosystem-based management of water resources.

  16. Changes of soil bacterial diversity as a consequence of agricultural land use in a semi-arid ecosystem.

    Directory of Open Access Journals (Sweden)

    Guo-Chun Ding

    Full Text Available Natural scrublands in semi-arid deserts are increasingly being converted into fields. This results in losses of characteristic flora and fauna, and may also affect microbial diversity. In the present study, the long-term effect (50 years of such a transition on soil bacterial communities was explored at two sites typical of semi-arid deserts. Comparisons were made between soil samples from alfalfa fields and the adjacent scrublands by two complementary methods based on 16S rRNA gene fragments amplified from total community DNA. Denaturing gradient gel electrophoresis (DGGE analyses revealed significant effects of the transition on community composition of Bacteria, Actinobacteria, Alpha- and Betaproteobacteria at both sites. PhyloChip hybridization analysis uncovered that the transition negatively affected taxa such as Acidobacteria, Chloroflexi, Acidimicrobiales, Rubrobacterales, Deltaproteobacteria and Clostridia, while Alpha-, Beta- and Gammaproteobacteria, Bacteroidetes and Actinobacteria increased in abundance. Redundancy analysis suggested that the community composition of phyla responding to agricultural use (except for Spirochaetes correlated with soil parameters that were significantly different between the agricultural and scrubland soil. The arable soils were lower in organic matter and phosphate concentration, and higher in salinity. The variation in the bacterial community composition was higher in soils from scrubland than from agriculture, as revealed by DGGE and PhyloChip analyses, suggesting reduced beta diversity due to agricultural practices. The long-term use for agriculture resulted in profound changes in the bacterial community and physicochemical characteristics of former scrublands, which may irreversibly affect the natural soil ecosystem.

  17. Relation between seasonally detrended shortwave infrared reflectance data and land surface moisture in semi-arid Sahel

    DEFF Research Database (Denmark)

    Olsen, Jørgen Lundegaard; Ceccato, Pietro; Proud, Simon Richard;

    2013-01-01

    In the Sudano-Sahelian areas of Africa droughts can have serious impacts on natural resources, and therefore land surface moisture is an important factor. Insufficient conventional sites for monitoring land surface moisture make the use of Earth Observation data for this purpose a key issue...

  18. Sustainability of land reclamation measures in erosional badlands: A comparative perspective on semi-arid landscapes of South Morocco and Central India

    Science.gov (United States)

    Marzolff, Irene; Pani, Padmini; Mohapatra, Surya; Ghafrani, Hassan; Aït Hssaine, Ali

    2015-04-01

    Semi-arid regions around the world, where gully erosion is a major land-degradation process, are particularly vulnerable to the effects of population growth and land-use change. In regions with high pressure on land as a resource - either due to population pressure or to agricultural intensification or both - erosion-affected areas are increasingly being reclaimed as agricultural land in an endeavour to turn marginal or unused land into fields, plantations, greenhouses or even building ground. Depending on the severity and depth of the erosion processes, this may be done by ploughing (for ephemeral gullying), land-levelling with bulldozers (for permanent gullies and badlands) or infilling with ex situ material (for large and deep gullies and badlands). The success of such measures, which also depends on subsequent soil-erosion protection, varies strongly and is not yet well researched. The little developed part of Lower Chambal Valley (Madhya Pradesh) is one of the four regions most badly affected by gully and badland erosion in India. Around 80% of the rural population are dependent on agriculture, an estimated 5000 km² are affected by gullies and badlands as deep as 80 m. Various land reclamation measures have been conducted on widely different spatial scales both by governmental and non-governmental agencies and individual farmers. However, the reclamation strategies of rich and poor farmers also exhibit significant differences, and agricultural use that often is based on short-term economic needs of households leads to inefficient land-use practices particularly in land-levelled and reclaimed areas. Although set in rural surroundings as well, the Souss Valley (South Morocco) is characterized by highly dynamic land-use changes with transformations from traditional agriculture to vast agro-industrial plantations of citrus fruits, bananas and vegetables. These plantations, as well as other arable land, are threatened by gullies and other forms of soil erosion

  19. Development of Novel Water-extraction System with Thermoelectric Module Using Solar and Wind Power in Arid Land

    Institute of Scientific and Technical Information of China (English)

    HAYASHI Tsutomu; TAGAWA Kotaro; TANAKA Kenji; MORITA Yasunari

    2010-01-01

    This study aimed to develop a water-extraction system which could produce the fresh water from the air in arid regions and which used renewable energies as the electric power source. In this paper, the experiments for water extraction from the air were carried out by using the novel multi-stage water-extraction device with Peltier deices for two cases of temperature and related humidity of the air. One was the case where the temperature and the related humidity of the air were constant, and the other was the case where they were simulated the variation of the temperature and related humidity of the air in a day of summer and spring in Loess Plateau, China. The effects of the temperature and related humidity of the atmospheric air and supply the electric power to Peltier devices on performance of water production of the device were investigated and reported.

  20. Revegetation Plan for Areas of the Fitzner-Eberhardt Arid Lands Ecology Reserve Affected by Decommissioning of Buildings and Infrastructure and Debris Clean-up Actions

    Energy Technology Data Exchange (ETDEWEB)

    Downs, Janelle L.; Durham, Robin E.; Larson, Kyle B.

    2011-01-01

    The U.S. Department of Energy (DOE), Richland Operations Office is working to remove a number of facilities on the Fitzner Eberhardt Arid Lands Ecology Reserve (ALE), which is part of the Hanford Reach National Monument. Decommissioning and removal of buildings and debris on ALE will leave bare soils and excavated areas that need to be revegetated to prevent erosion and weed invasion. Four main areas within ALE are affected by these activities (DOE 2009;DOE/EA-1660F): 1) facilities along the ridgeline of Rattlesnake Mountain, 2) the former Nike missile base and ALE HQ laboratory buildings, 3) the aquatic research laboratory at Rattlesnake Springs area, and 4) a number of small sites across ALE where various types of debris remain from previous uses. This revegetation plan addresses the revegetation and restoration of those land areas disturbed by decommissioning and removal of buildings, facilities and associated infrastructure or debris removal. The primary objective of the revegetation efforts on ALE is to establish native vegetation at each of the sites that will enhance and accelerate the recovery of the native plant community that naturally persists at that location. Revegetation is intended to meet the direction specified by the Environmental Assessment (DOE 2009; DOE/EA-1660F) and by Stipulation C.7 of the Memorandum of Agreement (MOA) for the Rattlesnake Mountain Combined Community Communication Facility and InfrastructureCleanup on the Fitzner/Eberhardt Arid Lands Ecology Reserve, Hanford Site, Richland Washington(DOE 2009; Appendix B). Pacific Northwest National Laboratory (PNNL) under contract with CH2M Hill Plateau Remediation Company (CPRC) and in consultation with the tribes and DOE-RL developed a site-specific strategy for each of the revegetation units identified within this document. The strategy and implementation approach for each revegetation unit identifies an appropriate native species mix and outlines the necessary site preparation activities

  1. Detecting new Buffel grass infestations in Australian arid lands: evaluation of methods using high-resolution multispectral imagery and aerial photography.

    Science.gov (United States)

    Marshall, V M; Lewis, M M; Ostendorf, B

    2014-03-01

    We assess the feasibility of using airborne imagery for Buffel grass detection in Australian arid lands and evaluate four commonly used image classification techniques (visual estimate, manual digitisation, unsupervised classification and normalised difference vegetation index (NDVI) thresholding) for their suitability to this purpose. Colour digital aerial photography captured at approximately 5 cm of ground sample distance (GSD) and four-band (visible–near-infrared) multispectral imagery (25 cm GSD) were acquired (14 February 2012) across overlapping subsets of our study site. In the field, Buffel grass projected cover estimates were collected for quadrates (10 m diameter), which were subsequently used to evaluate the four image classification techniques. Buffel grass was found to be widespread throughout our study site; it was particularly prevalent in riparian land systems and alluvial plains. On hill slopes, Buffel grass was often present in depressions, valleys and crevices of rock outcrops, but the spread appeared to be dependent on soil type and vegetation communities. Visual cover estimates performed best (r 2 0.39), and pixel-based classifiers (unsupervised classification and NDVI thresholding) performed worst (r 2 0.21). Manual digitising consistently underrepresented Buffel grass cover compared with field- and image-based visual cover estimates; we did not find the labours of digitising rewarding. Our recommendation for regional documentation of new infestation of Buffel grass is to acquire ultra-high-resolution aerial photography and have a trained observer score cover against visual standards and use the scored sites to interpolate density across the region.

  2. Small-Scale Vertical Distribution of Bacterial Biomass and Diversity in Biological Soil Crusts from Arid Lands in the Colorado Plateau

    Science.gov (United States)

    Garcia-Pichel, F.; Johnson, S.L.; Youngkin, D.; Belnap, J.

    2003-01-01

    We characterized, at millimeter resolution, bacterial biomass, diversity, and vertical stratification of biological soil crusts in arid lands from the Colorado Plateau. Microscopic counts, extractable DNA, and plate counts of viable aerobic copiotrophs (VAC) revealed that the top centimeter of crusted soils contained atypically large bacterial populations, tenfold larger than those in uncrusted, deeper soils. The plate counts were not always consistent with more direct estimates of microbial biomass. Bacterial populations peaked at the immediate subsurface (1-2 mm) in light-appearing, young crusts, and at the surface (0-1 mm) in well-developed, dark crusts, which corresponds to the location of cyanobacterial populations. Bacterial abundance decreased with depth below these horizons. Spatially resolved DGGE fingerprints of Bacterial 16S rRNA genes demonstrated the presence of highly diverse natural communities, but we could detect neither trends with depth in bacterial richness or diversity, nor a difference in diversity indices between crust types. Fingerprints, however, revealed the presence of marked stratification in the structure of the microbial communities, probably a result of vertical gradients in physicochemical parameters. Sequencing and phylogenetic analyses indicated that most of the naturally occurring bacteria are novel types, with low sequence similarity (83-93%) to those available in public databases. DGGE analyses of the VAC populations indicated communities of lower diversity, with most types having sequences more than 94% similar to those in public databases. Our study indicates that soil crusts represent small-scale mantles of fertility in arid ecosystems, harboring vertically structured, little-known bacterial populations that are not well represented by standard cultivation methods.

  3. Utilisation of priority traditional medicinal plants and local people's knowledge on their conservation status in arid lands of Kenya (Mwingi District

    Directory of Open Access Journals (Sweden)

    Njoroge Grace N

    2010-08-01

    Full Text Available Abstract Mwingi District lies within the Kenyan Arid and Semiarid lands (ASALs in Eastern Province. Although some ethnobotanical surveys have been undertaken in some arid and semiarid areas of Kenya, limited studies have documented priority medicinal plants as well as local people's awareness of conservation needs of these plants. This study sought to establish the priority traditional medicinal plants used for human, livestock healthcare, and those used for protecting stored grains against pest infestation in Mwingi district. Further, the status of knowledge among the local people on the threat and conservation status of important medicinal species was documented. This study identified 18 species which were regarded as priority traditional medicinal plants for human health. In terms of priority, 8 were classified as moderate, 6 high, while 4 were ranked highest priority species. These four species are Albizia amara (Roxb. Boiv. (Mimosacaeae, Aloe secundiflora (Engl. (Aloaceae, Acalypha fruticosa Forssk. (Euphorbiaceae and Salvadora persica L. (Salvadoraceae. In regard to medicinal plants used for ethnoveterinary purposes, eleven species were identified while seven species were reported as being important for obtaining natural products or concoctions used for stored grain preservation especially against weevils. The data obtained revealed that there were new records of priority medicinal plants which had not been documented as priority species in the past. Results on conservation status of these plants showed that more than 80% of the respondents were unaware that wild medicinal plants were declining, and, consequently, few of them have any domesticated species. Some of the species that have been conserved on farm or deliberately allowed to persist when wild habitats are converted into agricultural lands include: Croton megalocarpus Hutch., Aloe secundiflora, Azadirachta indica A. Juss., Warburgia ugandensis Sprague, Ricinus communis L. and

  4. Land cover change detection based on satellite data for an arid area to the south of Aksu in Taklimakan desert

    Institute of Scientific and Technical Information of China (English)

    Kiyoshi; TSUCHIYA; Tamotsu; IGARSHI; Muhtar; QONG

    2010-01-01

    An experiment is made to detect the land-cover change in the area located to the south of Aksu in the northern Taklimakan desert through analyses of satellite data pixel by pixel basis. The analyzed data are those observed in the late summer and early autumn of 1973, 1977, 1993 and 1995. As a parameter of land-cover, SAVI (Soil Adjusted Vegetation Index) derived from the data of Landsat MSS and JERS-1 OPS (Optical Sensor) is used. The result indicates the increase of vegetation in the oasis areas, confluent area of the Yarkant and Kashgar Rivers and around reservoirs while little change occurs in the desert area. The 1973 satellite image shows the abundant flow in the Yarkant River while the river is almost dried up in the satellite images of later years. The trend of the decrease in the Hotan River flow is recognized although not so dramatic as that of the Yarkant River.

  5. Evaluating the effect of land use land cover change in a rapidly urbanizing semi-arid watershed on estuarine freshwater inflows

    Science.gov (United States)

    Sahoo, D.; Smith, P.; Popescu, S.

    2006-12-01

    Estuarine freshwater inflows along with their associated nutrient and metal delivery are influenced by the land use/land cover (LULC) and water management practices in the contributing watershed. This study evaluates the effect of rapid urbanization in the San Antonio River Watershed on the amount of freshwater inflow reaching the San Antonio-Guadalupe estuary on the Gulf Coast of Texas. Remotely sensed data from satellite imagery provided a source of reliable data for land use classification and land cover change analysis; while long time series of the geophysical signals of stream flow and precipitation provided the data needed to assess change in flow in the watershed. LULC was determined using LANDSAT (5 TM and 7 ETM) satellite images over 20 years (1985-2003). The LANDSAT images were classified using an ENVI. ISODATA classification scheme. Changes were quantified in terms of the urban expansion that had occurred in past 20 years using an urban index. Streamflow was analyzed using 20 years (1985-2004) of average daily discharge obtained from the USGS gauging station (08188500) closest to the headwaters of the estuary. Baseflow and storm flow were partitioned from total flow using a universally used baseflow separation technique. Precipitation data was obtained from an NCDC station in the watershed. Preliminary results indicate that the most significant change in land use over the 20 year period was an increase in the total amount of impervious area in the watershed. This increase in impervious area was accompanied by an increase in both total streamflow and in baseflow over the same period. The investigation did not show a significant change in total annual precipitation from 1990 to 2004. This suggests that the increase in streamflow was more influenced by LULC than climate change. One explanation for the increase in baseflow may be an increase in return flows resulting from an increase in the total number of wastewater treatment plants in the watershed.

  6. Validation of the CORINE land cover database in a pilot zone under semi-arid conditions in La Mancha (Spain)

    OpenAIRE

    Mañas, Martín de Santa Olalla; Soria, Cabañero; Ramírez, Artigao

    2003-01-01

    El programa CORINE (iniciado en 1985) ha creado un Sistema de Información referido a los países de la Unión Europea, que suministra datos administrativos, geográficos, de usos del suelo, cubierta vegetal, así como diferentes parámetros ambientales (CORINE, 1994). La base de datos CORINE de cobertura terrestre (land cover)  ofrece una valiosa información acerca de las distintas cubiertas del suelo en el área cartografiada. Actualmente, toda la Península Ibérica se encuentra accesible en esta b...

  7. Soils of the Pacific Northwest shrub-steppe. Occurrence and properties of soils on the Arid Land Ecology Reserve, Hanford Reservation

    International Nuclear Information System (INIS)

    The soils of the Arid Land Ecology Reserve, encompassing the IBP Grassland Biome intensive study site on the ERDA Hanford Reservation, are representative of a larger geographical region including much of the Columbia Plateau and Pacific Northwest shrub-steppe. This results from a unique diversity in parent materials of mixed origin derived from the loess eolian, lacustrine and stream-laid material including glacial outwashes, river terraces, flood plains and alluvial fans and meteorological factors accompanying a marked change in altitude within the Reserve resulting in development of soils over a range in temperature, moisture and vegetative regimes. The Reserve and the IBP Grassland Biome intensive study site serve as valuable, representative areas for the study of soil genesis and morphology in the shrub-steppe. The role of soils can be determined in basic environmental processes involving the flow of energy, cyclization of nutrients or the fate and behavior of pollutants. These processes may be examined to provide baseline information for comparison to other, more disturbed areas. Or, for investigative purposes, processes may be systematically altered to determine the influence of soil-perturbing activities such as agriculture, mining and industry on the terrestrial ecosystem

  8. Biological soil crusts: An organizing principle in dryland ecosystems (aka: the role of biocrusts in arid land hydrology)

    Science.gov (United States)

    Chamizo, Sonia; Belnap, Jayne; Elridge, David J; Issa, Oumarou M

    2016-01-01

    Biocrusts exert a strong influence on hydrological processes in drylands by modifying numerous soil properties that affect water retention and movement in soils. Yet, their role in these processes is not clearly understood due to the large number of factors that act simultaneously and can mask the biocrust effect. The influence of biocrusts on soil hydrology depends on biocrust intrinsic characteristics such as cover, composition, and external morphology, which differ greatly among climate regimes, but also on external factors as soil type, topography and vegetation distribution patterns, as well as interactions among these factors. This chapter reviews the most recent literature published on the role of biocrusts in infiltration and runoff, soil moisture, evaporation and non-rainfall water inputs (fog, dew, water absorption), in an attempt to elucidate the key factors that explain how biocrusts affect land hydrology. In addition to the crust type and site characteristics, recent studies point to the crucial importance of the type of rainfall and the spatial scale at which biocrust effects are analyzed to understand their role in hydrological processes. Future studies need to consider the temporal and spatial scale investigated to obtain more accurate generalizations on the role of biocrusts in land hydrology.

  9. Numerical model to evaluate the mitigation strategies to combat desertification and drought in the arid land of northern Chile.

    Science.gov (United States)

    Salinas, Carla; Mendieta, Jon

    2014-05-01

    Desertification is considered a global environmental problem with political and socioeconomic implications. Desertification, exacerbated by climate change, is the largest environmental problem in Chile affecting almost two third of the national territory. This study takes place in a latitudinal gradient of the north-central Chilean drylands, where desertification is a threat to agriculture, livestock and forestry (ALF). The critical areas or priority areas for combating desertification are the northernmost areas of the region under study. In the context of the United Nations Convention to Combat Desertification (UNCCD) and the implementation of the Chilean National Action Programme (NAP), the country is conducting policies and investing in mitigation strategies to combat land degradation and desertification. The main objective of this study is the development of an integrative methodological approach using real data of the territorial and socioeconomic indicators. With the proposed methodology we assess the impact of the mitigation and land degradation strategies supported by the ALF promotion agencies in the fight against desertification, projecting different scenarios of change. The data were collected in 2008 in Santiago, Chile. The results of the Principal Component Analysis (PCA) suggest that technical irrigation and the improvement of grasslands and pastures play an important role in the fight against desertification. The results of the model projections are consistent, suggesting that the efforts of the ALF promotion agencies have a positive impact in fighting desertification. Inaction of ALF mitigation strategies would increase desertification. This methodological approach, performed with real data, can also determine the main causes of desertification in such a complex area as the studied one, where we can find the desert itself, and its desertification endangered valleys, the Andean plateau, the transitional area and the southern regions. Ii is also a

  10. CHARACTERISTICS OF ARIDITY CONDITIONS IN SOUTH DOBRUDJA

    OpenAIRE

    A. TISCOVSCHI; GABRIELA MANEA; O. COCOS; IULIANA VIJULIE; ROXANA CUCULICI

    2013-01-01

    Characteristics of Aridity Conditions in South Dobrudja. For most people, the arid and semi-arid lands are those where precipitation is low (less than 200 mm per year), and yet enough for supplying streams capable of temporarily carrying the debris resulted from weathering, but insufficient for encouraging the development of a vegetal cover meant to protect the soil blanket against eroding agents. The drought is a major and permanent climatic risk for the Dobrudja territory as a whole and for...

  11. HAPEX-Sahel: a large-scale study of land-atmosphere interactions in the semi-arid tropics

    Directory of Open Access Journals (Sweden)

    J.-P. Goutorbe

    Full Text Available The Hydrologic Atmospheric Pilot EXperiment in the Sahel (HAPEX-Sahel was carried out in Niger, West Africa, during 1991 - 1992, with an intensive observation period (IOP in August - October 1992. It aims at improving the parameterization of land surface atmosphere interactions at the Global Circulation Model (GCM gridbox scale. The experiment combines remote sensing and ground based measurements with hydrological and meteorological modelling to develop aggregation techniques for use in large scale estimates of the hydrological and meteorological behaviour of large areas in the Sahel. The experimental strategy consisted of a period of intensive measurements during the transition period of the rainy to the dry season, backed up by a series of long term measurements in a 1° by 1° square in Niger. Three "supersites" were instrumented with a variety of hydrological and (micro meteorological equipment to provide detailed information on the surface energy exchange at the local scale. Boundary layer measurements and aircraft measurements were used to provide information at scales of 100 - 500 km2. All relevant remote sensing images were obtained for this period. This programme of measurements is now being analyzed and an extensive modelling programme is under way to aggregate the information at all scales up to the GCM grid box scale. The experimental strategy and some preliminary results of the IOP are described.

  12. How rural land use management facilitates drought risk adaptation in a changing climate - A case study in arid northern China.

    Science.gov (United States)

    Lei, Yongdeng; Zhang, Hailin; Chen, Fu; Zhang, Linbo

    2016-04-15

    Under a warming climate, frequent drought and water scarcity in northern China have severely disrupted agricultural production and posed a substantial threat to farmers' livelihoods. Based on first-hand data collected through in-depth interviews with local managers and farmer households, this study evaluated the effectiveness of rural land use management in mitigating drought risk, ensuring food security and improving farmers' livelihoods. Our findings indicate that a) reforestation on low-yield cropland not only can improve the eco-environment but can also prominently mitigate the production risk to local farmers; b) replacing the traditional border irrigation with sprinkler irrigation has substantially curbed agricultural water usage and increased the per unit of output; and c) in recent years, instead of planting water-intensive grain crops, local farmers cultivated more forage crops to raise animals, which greatly diversified their income sources and reduced the drought risk of agricultural production. By performing an empirical case study in drought-prone Inner Mongolia, this study provides decision-makers with insights into how to strategically adapt to drought risk and reduce rural poverty within the broader context of climate change. PMID:26815296

  13. Characterization of water and energy exchanges for rainfed olive orchards in a semi-arid land : modeling and integration of remote sensing data

    Science.gov (United States)

    Chebbi, Wafa; Le Dantec, Valérie; Boulet, Gilles; Lili Chabaane, Zohra; Fanise, Pascal; Mougenot, Bernard; Ayari, Hassan; Cheheb, Hechmi; Rivalland, Vincent; Zribi, Mehrez

    2016-04-01

    Evapotranspiration is one of the most important fluxes of the water balance in semi-arid areas. The components of evapotranspiration are soil evaporation (E) and transpiration (T) through the stomata of the plants. The estimation of crop actual transpiration is a major issue in central and south Tunisia because it affects irrigation scheduling, crop growth and yield. Olive is well adapted to the soil and climate conditions of Tunisia and covers an entire agricultural land of 1.7 million hectares representing nearly 79% of the total tree area. The southern part of the Mediterranean basin faces climate change and could affect olive tree production in rainfed conditions. The hydrological functioning of sparse olive trees is difficult to characterize because of its low LAI. For a good comprehension of the functionning of the water and energy transfers throuigh the Soil-Plant-Atmosphere continuum, we combine the eddy covariance method, soil water content measurements and sap flow method. The main objectives of this study are 1) to characterize the eco-hydrological processes of sparse olive trees from a dedicated experimental protocol and a SVAT model adapted to the sparse characteristic of such crop 2) to analyze the vulnerability of the system to climate change. First, we identify the factors of changes of transpiration at different time steps and characterized the different water stress levels by the combined use of different types of ecophysiological (sap flow) and spectral (photochemical reflectance index) measurements. Then, we estimate the percentage of evaporation, transpiration and the total evapotranspiration (ET). We compared scaled evapotranspiration values (the fraction of cover fraction contributing to the footprint of total ET fluxes) with scaled sap flow values. The sum of soil evaporation and transpiration matches well the total ET. A SVAT model is currently be applied and expanded to represent the impact of canopy structure on radiative and turbulent

  14. 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.

  15. The water balance of two semi-arid shrubs on abandoned land in South-Eastern Spain after cold season rainfall

    Directory of Open Access Journals (Sweden)

    N. Archer

    2002-01-01

    Full Text Available The inland, mountainous marginal areas (land abandoned by farming and colonised by shrubs of the Iberian Peninsular, Spain, generally receive a higher rainfall than the coastal areas (Lazaro and Rey, 1991 and may store water after cold season (autumn and winter rainfall. By measuring runoff, change of soil water content and rainfall, this study tests the hypothesis that two shrubs on two sites on abandoned land do not use all the water available after cold season rainfall. One site was on an upper alluvial slope dominated by Anthyllis cytisoides and the other on a lower alluvial slope dominated by Retama sphaerocarpa. The root systems of A. cytisoides and R. sphaerocarpa penetrate to 3 m and 20 m, respectively. A. cytisoides senesces during the dry season and R. sphaerocarpa is evergreen. The water balance is dominated by high actual evapotranspiration (ET, which is limited by rainfall. Reference evapotranspiration was high; runoff was low and soil water storage occurred above 2 m depth. ET and water storage were highest under A. cytisoides shrubs. Runoff was lower on the ‘Anthyllis’ site. The spatial variability of soil water is high and the problems of its measurement are discussed. The quantity of rainfall infiltrated was greater under shrubs than grass-areas, suggesting that shrub roots facilitated preferential flow. The growing season of A. cytisoides began when water was available in the upper soil layers and senescence occurred when the upper soil layers dried to less than 4% water content. A. cytisoides, therefore, relies on water from these layers. The main growth of R. sphaerocarpa occurred when the upper soil layers were relatively dry, so that R. sphaerocarpa must extract water from deeper layers. Results suggest that A. cytisoides accumulates rainfall and runoff and directs water to lower layers for later use, while R. sphaerocarpa extracts water from deeper soil layers. By mid-summer both shrubs had extracted all the available

  16. Shallow land burial technology - ARID

    International Nuclear Information System (INIS)

    Scope of the tasks being performed by Los Alamos will be identified. Emphasis will be placed upon the geotechnical work. Important geotechnical properties of a low-level waste disposal site include hydraulic conductivity consolidation, and shear strength of the applicable medium. The hydraulic conductivity of crushed Bandelier tuff has been assessed using the instantaneous profile method. The best fit of hydraulic conductivity as a function of water content was found to be a power function. The coefficient of consolidation was difficult to measure because of the relatively high hydraulic conductivity. The repose angle for crushed tuff is higher than the normally expected range. This is probably because of a higher than average angularity and surface roughness. The high coefficient of consolidation and high internal friction angle make finely crushed tuff a material with ideal mechanical characteristics. The drawback is that a high coefficient of consolidation is linked to a high hydraulic conductivity

  17. 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

  18. Fiscal 1997 report on the survey of biological CO2 fixation using arid land and oligotrophic waters; 1997 nendo chosa hokokusho (kansochi, hin`eiyo kaiiki wo riyoshita seibutsuteki CO2 kotei ni kansuru chosa)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    This survey is aimed to investigate various measures to be taken for biological CO2 fixation, to synthetically study feasibilities of the measures from various aspects of CO2 fixation mechanism, scale, speed, and environmental effects and technical problems in case of introducing those, and to assess the measures quantitatively. In this fiscal year, a study was proceeded with of possibilities of carbon fixation by afforestation and that by fertilization into ocean. The paper defined significance of afforestation in arid land, and especially advantages in conducting researches in West Australia. Relationships were examined among afforestation, precipitation and topography. The result of the survey was described of water- and salt-transfer simulation methods. Studies of arid land were made in terms of photosynthetic speed, transpiration speed, soil characteristics, measuring methods for precipitation and vaporization amount, and the examples. Seven places of Leonora where water source and water quality were examined were selected, and the measuring results were described. The paper summed up the state of utilization of biomass energy obtained from forest and commented on a scenario on tree-planting. Finally, a possibility was stated of the carbon fixation by fermentation into ocean. 178 refs., 121 figs., 53 tabs.

  19. Land Degradation Control in Arid Ecosystem Under Climate Change Context%气候变化背景下干旱生态系统土地退化防治

    Institute of Scientific and Technical Information of China (English)

    江泽慧

    2012-01-01

    气候变化是当今全球陆地生态系统所面临的最大胁迫因素。探讨气候变化背景下干旱生态系统土地退化防治,增强减缓和适应气候变化的能力,逐步恢复土地生态系统原先所具有的综合生产潜力,是亟待解决的重要课题。文中分析了气候变化对干旱生态系统土地退化的影响,从综合生态系统管理的视角,探讨了保护与恢复森林、草地、农田生态系统以增强应对气候变化的能力以及改善民生的途径,以期为全球气候变化背景下土地退化防治和干旱生态系统可持续管理提供新的思路。%Climate change is the largest stress factor challenging global territorial ecosystem.The discussion on land degradation control in arid ecosystem under the context of climate change for increasing the capacity to mitigate and adapt to the climate change and gradually restoring the integrated production potential originally possessed by land ecosystem is a pressing issue to address.The paper analyzed the effect of climate change on land degradation in arid ecosystem,and described the protection and rehabilitation of forest,grassland and farmland ecosystems,the enhancement of the response to climate change and the improvement of people's livelihood from the viewpoint of integrated ecosystem management.This study is expected to offer a new concept for land degradation control and sustainable management of arid ecosystem in the context of global climate change.

  20. What does the future hold for semi-arid Mediterranean agro-ecosystems? - Exploring cellular automata and agent-based trajectories of future land use change

    NARCIS (Netherlands)

    Nainggolan, D.; Termansen, M.; Fleskens, L.; Hubacek, K.; Reed, M.S.; Vente, de J.; Boix-Fayos, C.

    2012-01-01

    Exploring how land use and the management of agro-ecosystems may evolve in the future is important for advancing scientific understanding and for informing policy makers and land managers of ways to respond and adapt sustainably to future change. In this paper, we investigate the future land-use tra

  1. Simulation of Sediment Yield in a Semi-Arid River Basin under Changing Land Use: An Integrated Approach of Hydrologic Modelling and Principal Component Analysis

    Directory of Open Access Journals (Sweden)

    Charles Gyamfi

    2016-11-01

    Full Text Available Intensified human activities over the past decades have culminated in the prevalence of dire environmental consequences of sediment yield resulting mainly from land use changes. Understanding the role that land use changes play in the dynamics of sediment yield would greatly enhance decision-making processes related to land use and water resources management. In this study, we investigated the impacts of land use and cover changes on sediment yield dynamics through an integrated approach of hydrologic modelling and principal component analysis (PCA. A three-phase land use scenario (2000, 2007 and 2013 employing the “fix-changing” method was used to simulate the sediment yield of the Olifants Basin. Contributions in the changes in individual land uses to sediment yield were assessed using the component and pattern matrixes of PCA. Our results indicate that sediment yield dynamics in the study area is significantly attributed to the changes in agriculture, urban and forested lands. Changes in agriculture and urban lands were directly proportional to sediment yield dynamics of the Olifants Basin. On the contrary, forested areas had a negative relationship with sediment yield indicating less sediment yield from these areas. The output of this research work provides a simplistic approach of evaluating the impacts of land use changes on sediment yield. The tools and methods used are relevant for policy directions on land and water resources planning and management.

  2. STATUS AND DEVELOPMENT OF FLOOD LAND IN THE WEST SEMI-ARID AREA IN HEILONGJIANG PROVINCE%黑龙江省西部半干旱区河滩地治理开发构想

    Institute of Scientific and Technical Information of China (English)

    王丽敏; 高凤山; 张福平; 华淑丽

    2001-01-01

    cording to the natural conditions and the management situation of the flood land of the west semi-arid Area of Heilongjiang province, it was presented a framing conception for controlling and developing the flood land, that was to comprehensively control, for example, taking the vegetation construction as basis and by means of engineering measures, to develop all-round of agriculture, forestry, animal husbantry, water conservancy, fishery, sideline and enterprise, and to combine control with development so that flood land can become a benign system that both the local economy and the ecology will be developed.%从黑龙江省西部半干旱地区自然概况及河滩地经营现状出发,提出了以植被建设为基础,工程措施为手段,进行全面治理;根据滩地的实际情况,结合农、林、牧、水、渔、副、企各业进行综合开发,治理与开发并举,使滩地成为生态经济良性系统,促进地方经济发展与生态恢复。

  3. Community based conservation and ecotourism as an environmental management practice for climate change adaptation in Ewaso Nyiro arid land ecosystem, Samburu County Kenya

    Directory of Open Access Journals (Sweden)

    Ogara OW

    2013-05-01

    Full Text Available Communities inhabiting the fragile Arid and Semi-Arid (ASALs ecosystems of Northern Kenya are strongly impacted by climate variability and change. Their pastoral livelihoods are threatened. Community based approach to environmental resources conservation and ecotourism have provided an alternative source of livelihood worth considering. This study was conducted in two districts; Samburu and Laikipia, Northern Kenya in three community based conservancies of Namunyak, Naibung’a and Westgate. The study used quantitative and qualitative participatory research design. The findings indicated that community based conservation and ecotourism indeed was an appropriate practice for community adaptation to climate change impacts in the ASALs. It offered opportunities for livelihood diversification away from pastoralism that was resilient enough to climate change, and provided the community with a sense of ownership for their resources and created community cohesion which is an important asset for rural community social capital. The study concluded that community based conservation should be looked at as a strategy for climate change adaptation and community resource management.

  4. 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.

  5. Assessing the Impacts of Land Use Change from Cotton to Perennial Bioenergy Grasses on Hydrological Fluxes and Water Quality in a Semi-Arid Agricultural Watershed Using the APEX Model

    Science.gov (United States)

    Chen, Y.; Ale, S.; Rajan, N.

    2015-12-01

    The semi-arid Texas High Plains (THP) region, where cotton (Gossypium hirsutum L.) is grown in vast acreage, has the potential to grow perennial bioenergy grasses. A change in land use from cotton cropping systems to perennial grasses such as Alamo switchgrass (Panicum virgatum L.) and Miscanthus giganteus (Miscanthus sinensis Anderss. [Poaceae]) can significantly affect regional hydrologic cycle and water quality. Assessing the impacts of this potential land use change on hydrology and water quality enables the environmental assessment of feasibility to grow perennial grasses in this region to meet the U.S. national bioenergy target of 2022. The Agricultural Policy/Environmental eXtender (APEX) model was used in this study to assess the impacts of replacing cotton with switchgrass and Miscanthus on water and nitrogen balances in the upstream subwatershed of the Double Mountain Fork Brazos watershed in the THP, which contains 52% cotton land use. The APEX model was initially calibrated against observed streamflow and crop yield data. Since observed data on nitrogen loads in streamflow was not available for this subwatershed, we calibrated the APEX model against the SWAT-simulated nitrogen loads at the outlet of this subwatershed, which were obtained in a parallel study. The calibrated APEX model was used to simulate the impacts of land use change from cotton to Miscanthus and switchgrass on surface and subsurface water and nitrogen balances. Preliminary results revealed that the average (1994-2009) annual surface runoff decreased by 84% and 66% under the irrigated and dryland switchgrass scenarios compared to the baseline scenarios. Average annual percolation increased by 106% and 57% under the irrigated and dryland switchgrass scenarios relative to the baseline scenarios. Preliminary results also indicated Miscanthus and switchgrass appeared to be superior to cotton in terms of better water conservation and water quality, and minimum crop management requirements.

  6. The water balance of two semi-arid shrubs on abandoned land in South-Eastern Spain after cold season rainfall

    OpenAIRE

    Archer, N; Hess, T.; Quinton, J

    2002-01-01

    The inland, mountainous marginal areas (land abandoned by farming and colonised by shrubs) of the Iberian Peninsular, Spain, generally receive a higher rainfall than the coastal areas (Lazaro and Rey, 1991) and may store water after cold season (autumn and winter) rainfall. By measuring runoff, change of soil water content and rainfall, this study tests the hypothesis that two shrubs on two sites on abandoned land do not use all the water available after cold season rainfall. One site was on ...

  7. The water balance of two semi-arid shrubs on abandoned land in South-Eastern Spain after cold season rainfall

    OpenAIRE

    Archer, N; Hess, T.; Quinton, J

    2002-01-01

    The inland, mountainous marginal areas (land abandoned by farming and colonised by shrubs) of the Iberian Peninsular, Spain, generally receive a higher rainfall than the coastal areas (Lazaro and Rey, 1991) and may store water after cold season (autumn and winter) rainfall. By measuring runoff, change of soil water content and rainfall, this study tests the hypothesis that two shrubs on two sites on abandoned land do not use all the water available after cold season rainfall...

  8. Assessing the effects of land use changes on soil sensitivity to erosion in a highland ecosystem of semi-arid Turkey.

    Science.gov (United States)

    Bayramin, Ilhami; Basaran, Mustafa; Erpul, Günay; Canga, Mustafa R

    2008-05-01

    There has been increasing concern in highlands of semiarid Turkey that conversion of these systems results in excessive soil erosion, ecosystem degradation, and loss of sustainable resources. An increasing rate of land use/cover changes especially in semiarid mountainous areas has resulted in important effects on physical and ecological processes, causing many regions to undergo accelerated environmental degradation in terms of soil erosion, mass movement and reservoir sedimentation. This paper, therefore, explores the impact of land use changes on land degradation in a linkage to the soil erodibility, RUSLE-K, in Cankiri-Indagi Mountain Pass, Turkey. The characterization of soil erodibility in this ecosystem is important from the standpoint of conserving fragile ecosystems and planning management practices. Five adjacent land uses (cropland, grassland, woodland, plantation, and recreational land) were selected for this research. Analysis of variance showed that soil properties and RUSLE-K statistically changed with land use changes and soils of the recreational land and cropland were more sensitive to water erosion than those of the woodland, grassland, and plantation. This was mainly due to the significant decreases in soil organic matter (SOM) and hydraulic conductivity (HC) in those lands. Additionally, soil samples randomly collected from the depths of 0-10 cm (D1) and 10-20 cm (D2) with irregular intervals in an area of 1,200 by 4,200 m sufficiently characterized not only the spatial distribution of soil organic matter (SOM), hydraulic conductivity (HC), clay (C), silt (Si), sand (S) and silt plus very fine sand (Si + VFS) but also the spatial distribution of RUSLE-K as an algebraically estimate of these parameters together with field assessment of soil structure to assess the dynamic relationships between soil properties and land use types. In this study, in order to perform the spatial analyses, the mean sampling intervals were 43, 50, 64, 78, 85 m for

  9. 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.

  10. 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

  11. The Change of Land Use/Cover and Characteristics of Landscape Pattern in Arid Areas Oasis: An Application in Jinghe, Xinjiang

    Institute of Scientific and Technical Information of China (English)

    ZHANG Fei; TASHPOLAT·Tiyip; Hsiang-te KUNG; DING Jianli

    2010-01-01

    This paper uses 3S technology in macroscopic. Combining the integrated technology of ecological quantity analytical method with GIS technology through ArcGIS and Fragstats, the authors study the images of 1972, 1990, 2001, and 2005 and obtained land use data in Jinghe County. Then, the change of land use/cover and landscape pattern had been analyzed in the Jinghe County of Xinjiang. The conclusions were as follows: (1) The trend of LUCC is that the area of oasis expands slowly in nearly 33years between 1972 to 2005 in Jinghe County. (2) The water area is mainly influenced by Ebinur Lake, so the area expands a little in this period. (3) The area of salinization-land expands at first and reduces later. The area of sand land decreases and the other land class increases, while the probability of transfer is always high. (4) Landscape change is also obvious throughout the decades.Overall, landscape density increases, the largest path index decreases at first and expends later, the weight area index decreases, and the shape of landscape becomes regulated. The nearest distances, the degrees of reunite, and outspread decreases. It shows that the connection of the main path in 1972 is better than 2005, wherein the patch becomes more complex. From the changes of Shannon's Diversity Index and Shannon's Evenness Index, we know that the diversity of landscape and the Interspersion Juxtaposition Index increase. The degree of diversity landscape and fragmentation increase also shows that the land uses become more complex. All in all, it is essential to intensify the spatial relationships among landscape elements and to maintain the continuity of landscape ecological process and pattern in the course of area expansion.

  12. 典型干旱区荒漠戈壁陆面参数的观测研究%Observation and Study of Land Surface Parameters over Gobi in Typical Arid Region

    Institute of Scientific and Technical Information of China (English)

    张强; 曹晓彦; 卫国安; 黄荣辉

    2002-01-01

    According to the need of popular land surface process models, characteristics and rules of some key land surface process and soil parameters over Gobi in typical arid region of Northwest China are analyzed by using the data observed during the intensive observation period of the Dunhuang Land-Surface Process Field Experiment (DLSPFE) (May-June 2000). Using the relative reflection as weighting factor, the weighted mean of the surface albedo over Dunhuang Gobi in typical arid region is calculated and its values are 0.255 -+ 0.021. After canceling the interference of the buildings, the mean values of the roughness length averaged with logarithm is 0.0019-+ 0.00071 m. After removing the influence of the oasis, the soil wetness factor computed with data under condition of no precipitation is 0.0045. After removing the influence of the precipitation, the mean values of the soil heat capacity over Dunhuang Gobi in typical arid region is 1.12 ×l06 J m -3K-1, a bit smaller than the values observed in HEIFE. But the soil heat diffusivity and conductivity are about one of those observed in HEIFE. The soil water content over Dunhuang Gobi in typical synoptic condition is very little and does not exceed 1% basically.%根据目前流行的陆面过程模式的需要,利用2000年5-6月敦煌陆面过程野外观测实验加强期的观测资料,分析了西北典型干旱区荒漠戈壁的一些关键陆面过程和土壤参数的特征和规律.并且利用相对反射为权重加权平均,计算得到典型干旱区敦煌荒漠戈壁的平均反射率为0.255±0.021;剔除建筑物干扰后,利用对数平均法计算的粗糙度长度平均值为0.0019±0.0007l m;剔除绿洲影响后,用无降水影响的资料确定出土壤湿度影响因子为0.0045;剔除降水影响后,用观测资料计算的敦煌典型干旱区荒漠戈壁的热容量平均值为l 1 2×l06J m-3 K-1,比"黑河试验"在戈壁和在其它沙漠观测的有关值略小一些,但热扩散率和热传

  13. The potential for SLM, facing human constraints, the case of the semi-arid agro-pastoral lands in the Atlantic plateaus, Morocco

    Science.gov (United States)

    Laouina, A.; Chaker, M.; Aderghal, M.; Machouri, N.; Alkarkouri, J.

    2012-04-01

    The agro-pastoral activity through its evolution, in the Atlantic plateaus of Morocco, led to unsuitable forms of resources use, which carried damage in the balance of water and the stability of land. It was thus necessary to start a revision of these practices and to set up improved forms of land use. The research made in the framework of the DESIRE project concerns the Sehoul commune, which presents a high rate of poverty and illiteracy, in spite of its location near Rabat, the capital of the country. Farming has as main objective to feed the livestock. The rain-based cereal cultivations, which still occupy more than 80% of the agricultural surface, reveals the stagnation of the techniques adopted and of the local knowledge. In collaboration with various stakeholders, technicians and farmers, the assessment with the WOCAT approach permitted to identify the main factors of constraints, responsible of the current spreading of land degradation mechanisms (forest clearing, shrubs cutting on the pastoral slopes, soil erosion, constitution of rills in the recently ploughed fields, incision of gullies and channels, mass movements on the banks of the deepest channels). These constraints derive from social evolution of the population during the last 60 years and mainly the rapid transformation of the rural structure of families to a new kind of farmers, more interested by what they can earn during their frequent movements to the city than by their own traditional agriculture. Due to the penetration of urban investment, direct overgrazing and indirect effect related to mismanagement of land for fodder production, operate massive damages to the vegetation cover and to the soil. It is why the SLM behavior, approaches and techniques have a very low rate of chance for success, without a deep change in term of land ownership, law constraints, agrarian structures, relations between the city and its vicinity, etc. Scenarios were built, based on various rates of land management

  14. Analyzing the anisotropy of thermal infrared emissivity over arid regions using a new MODIS land surface temperature and emissivity product (MOD21)

    OpenAIRE

    García Santos, Vicente; Coll Company, César; Valori Micó, Enric; Niclòs Corts, Raquel; Caselles Miralles, Vicente

    2015-01-01

    The MOD21 Land Surface Temperature and Emissivity (LST&E) product will be included in forthcoming Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 6. Surface temperature and emissivities for thermal bands 29 (8.55 μm), 31 (11 μm) and 32 (12 μm) will be retrieved using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Temperature and Emissivity Separation (TES) method adapted to MODIS at-sensor spectral radiances, previously corrected with the Water Vap...

  15. Sustainability of Smallholder Agriculture in Semi-Arid Areas under Land Set-aside Programs: A Case Study from China’s Loess Plateau

    Directory of Open Access Journals (Sweden)

    Qirui Li

    2016-04-01

    Full Text Available This article analyzes agricultural sustainability in the context of land degradation, rural poverty and social inequality, taking China’s Loess Hills as an example. The analysis attempts to understand the multi-dimensionality of sustainability at the farm level and its relationship with physical-socio-economic-infrastructural-technological framework conditions in the context of the land set-aside program viz. the Grain for Green Project (GGP. We developed composite indices of sustainability and its environmental, economic and social dimensions using a principal component analysis (PCA-based weighting scheme. Regression analyses were conducted to examine the relationship between the estimated sustainability indicators and the variables representing framework conditions of knowledge, demographics, resource endowment and production techniques. The stated analysis was conducted on a dataset collected by means of household surveys in 2014 in valleys and flood plain areas in Yanhe Township. Findings reveal hidden correlations among the indicators of environmental, economic, and social pillars of sustainability. The ratio of land under the conservation program to actual farmland emerged as a key determinant of overall agricultural sustainability and its social dimension, which reaches the maximum when the ratio is around 0.56 and 0.64, respectively. The results also show that there is need to balance off-farm and on-farm income diversification as well as highlight the role of women in ensuring the sustainability of farming households. The core achievement of the article is the definition of the thresholds for the land set-aside program and the identification of major determinants of agricultural sustainability in the rural Chinese context in particular and in rural farming communities in general.

  16. 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.

  17. The causes of land landscape changes in semi-arid area of Northwest China:a case study of Yulin city%中国西北半干旱区土地景观变化成因--以榆林市为例

    Institute of Scientific and Technical Information of China (English)

    郭丽英; 任志远; 刘彦随

    2006-01-01

    Rapid land landscape change has taken place in many arid and semi-arid regions such as the vulnerable ecological area over the last decade. In this paper, we quantified land landscape change of Yulin in this area between 1985 and 2000 using remote sensing and GIS. It was found that fallow landscape decreased by 125,148 hm2 while grassland and woodland increased by 107,975 hm2 and 17,157hm2, respectively. The major factors responsible for these changes are identified as the change in the government policy on preserving the environment, continued growth in mining, and urbanization. The efforts in restoring the deteriorated ecosystem have reaped certain benefits in reducing the spatial extent of sandy land through replacement by non-irrigated farmland, woodland and grassland. On the other hand,continued expansion of mining industry and urbanization has exerted adverse impacts on the land landscape. At present regional economic development conflicts directly with the protection of the natural environment. Such a conflict has caused the destruction to the land resources and fragmentation of the landscape accompanied by land desertification, the case is even serious in some localities.

  18. The water balance of two semi-arid shrubs on abandoned land in South-Eastern Spain after cold season rainfall

    Science.gov (United States)

    Archer, N.; Hess, T.; Quinton, J.

    The inland, mountainous marginal areas (land abandoned by farming and colonised by shrubs) of the Iberian Peninsular, Spain, generally receive a higher rainfall than the coastal areas (Lazaro and Rey, 1991) and may store water after cold season (autumn and winter) rainfall. By measuring runoff, change of soil water content and rainfall, this study tests the hypothesis that two shrubs on two sites on abandoned land do not use all the water available after cold season rainfall. One site was on an upper alluvial slope dominated by Anthyllis cytisoides and the other on a lower alluvial slope dominated by Retama sphaerocarpa. The root systems of A. cytisoides and R. sphaerocarpa penetrate to 3 m and 20 m, respectively. A. cytisoides senesces during the dry season and R. sphaerocarpa is evergreen. The water balance is dominated by high actual evapotranspiration (ET), which is limited by rainfall. Reference evapotranspiration was high; runoff was low and soil water storage occurred above 2 m depth. ET and water storage were highest under A. cytisoides shrubs. Runoff was lower on the ‘Anthyllis’ site. The spatial variability of soil water is high and the problems of its measurement are discussed. The quantity of rainfall infiltrated was greater under shrubs than grass-areas, suggesting that shrub roots facilitated preferential flow. The growing season of A. cytisoides began when water was available in the upper soil layers and senescence occurred when the upper soil layers dried to less than 4% water content. A. cytisoides, therefore, relies on water from these layers. The main growth of R. sphaerocarpa occurred when the upper soil layers were relatively dry, so that R. sphaerocarpa must extract water from deeper layers. Results suggest that A. cytisoides accumulates rainfall and runoff and directs water to lower layers for later use, while R. sphaerocarpa extracts water from deeper soil layers. By mid-summer both shrubs had extracted all the available water

  19. Utilization of satellite and close range digital data for mapping soils and soil properties in arid rangeland and agricultural rainfed and irrigated lands, Morocco

    Science.gov (United States)

    Naimi, Mustapha

    SPOT multispectral, spectroradiometric and ERS-1 radar data were used for mapping soils at Aarid and Sais sites in Morocco. Spectral curves at the Aarid site showed differences between soils and a significant amount of variability within soils. The reflectance variation was explained by the crusting, stoniness, and carbonate content of the soil surface. Although these factors explained some reflectance variation, intrinsic factors were used in regression models to predict color hue (Rsp2 = 0.34), and carbonates (0.66). Spectral reflectance differences at the Sais site were insignificant to discriminate soil types. Similar spectral behavior and low amplitude between soil curves were striking. Besides, soil intrinsic factors seemed meaningful in explaining reflectance variability. But, only sand and clay, carbonate, CEC, iron oxides and organic matter could be predicted. Extrinsic soil factors, such as tillage, crop residues and stoniness determined the reflectance. Use of SPOT imagery in mapping Aarid soils allowed us to conclude that: more than one soil transect was needed; primary SPOT data were as good as enhanced bands in mapping soils and land cover; mapping soils in locations away from the training site locations was difficult. Identification of soils using vegetation was very reliable for Stipa-covered soils. Although combined dual SPOT data was more suitable to depict linear features and geometric polygons, merged data improved significantly visual quality and image spatial detail for refining soil and land cover boundaries. Despite spectral differences between soils at the Sais site, soil mapping using multispectral data was very difficult because soil natural boundaries interfere with artificial borders of parcels. The integration of digital elevation model helped overcome limitations of SPOT digital data. Relationships between ERS-1 sigmasp0 and soil surface moisture and roughness were studied. Simple regressions between sigmasp0 and moisture was

  20. Mean Characteristics of Land Surface Key Parameters in Semi-Arid and Arid Regions of China in Summer of 2008%2008年夏季中国干旱-半干旱区陆面主要物理参数的平均特征

    Institute of Scientific and Technical Information of China (English)

    曾剑; 张强

    2012-01-01

    By picking 12stations whose underlying land surfaces include grassland,cropland,orchard and forest,the climatic characteristics of land surface key parameters are investigated using the data measured from July to September 2008,provided the Northern China Observation Coordination and Integration Research in Semiarid and Arid Regions.The roughness lengths for momentum,sensible heat and water vapor,and bulk transfer coefficient,albedo,and soil thermal conductivity and diffusivity are calculated and compared within various underlying land surfaces.The results are compared with the model theoretic reference values as well.It shows that the thermal-hydrologic properties of vegetated land surface and vegetation height significantly influence some key land surface parameters,and that there is no evident relations between soil thermal conductivity and diffusivity and underlying surface types.Specifically aerodynamic roughness length and momentum drag coefficient increase with increasing vegetation height,but albedo decreases with vegetation height.The measured aerodynamic roughness length of grassland is smaller than model reference value,but it is not true for cropland and orchard.The measured momentum drag coefficient is larger than model reference value over grassland,but it is smaller than model reference value in other underlying surfaces.The measured albedo is basically lower than its model reference value although it lies between visible albedo and near-infrared albedo.%采用2008年7-9月观测的中国干旱-半干旱区试验观测协同与集成研究资料,选取12个测站(涵盖不同气候环境区的草地、农田、果林和森林等下垫面)比较分析了干旱-半干旱区的动力、热力和水汽粗糙度长度、总体输送系数、反照率以及土壤热传导率和热扩散率的夏季平均特征,并与陆面模式的理论参考值进行了对比。结果表明,植被下垫面的水、热特性和植被高度对主要陆面参数有重

  1. Best land-use strategies towards sustainable biodiversity and land degradation management in semi-arid western rangelands in southern Africa, with special reference to ants as bio-indicators / Marisa Coetzee.

    OpenAIRE

    Coetzee, Marisa

    2006-01-01

    In South Africa, the unsustainable use of natural resources by domestic livestock has led to resource depletion and serious land degradation. Rangeland degradation, especially bush encroachment and soil erosion, is particularly acute in the North-West Province, where all districts show signs of desertification and a loss of biodiversity resulting in a deterioration of human and animal health. This has a major impact on livestock productivity and the economic viability of livestock farmi...

  2. Impact of tsetse control on land use in the semi-arid zone of Zimbabwe. Phase 2: Analysis of land use change by remote sensing imagery (NRI Bulletin 70)

    OpenAIRE

    Pender, J.; Mills, A. P.; Rosenberg, L. J

    1997-01-01

    Tsetse control is carried out to facilitate the expansion of livestock-based production systems in areas cleared of the threat of bovine trypanosomiasis. There is a growing awareness of the need for tsetse control to be considered an integral component of rural development and of the importance of monitoring and evaluating both the causes and consequences of potential land-use changes as a prerequisite for planning control operations. As part of an international programme to evaluate the envi...

  3. 1982~2010年气候与土地利用变化对无定河流域干旱指数变化的影响%Effects of Climate and Land Use Change on Changes of Aridity Index in Wudinghe River Basin, China:1982 to 2010

    Institute of Scientific and Technical Information of China (English)

    王志伟; 杨胜天; 孙影; 董宝恩; 赵长森; 赵海根; 周旭; 娄和震; 刘晓林

    2016-01-01

    基于1982~2010年无定河流域的遥感影像、气象和土地利用数据,利用PriestLey-TayLor公式计算出潜在蒸散发,进而得到干旱指数,将各气象因子与干旱指数差值进行叠加、逐象元相关分析,得到了无定河流域1982~2010年干旱指数的时空变化,并分析了气候和土地利用变化对干旱指数变化的影响。结果显示:(1)1982年、2010年干旱指数分别为2.01和2.13,总体趋势是趋干旱的;(2)干旱指数2.0以下的区域迅速减少,2.15以上的区域明显扩张;(3)干旱指数均呈现增加趋势,显著增加的区域集中于无定河流域中游和下游地区;(4)干旱指数变化同气温、水汽压、净辐射的变化成正相关,同降水量变化成负相关;(5)各种土地利用类型的干旱指数均呈现增长趋势,但是增长的幅度有所不同:林地>耕地>草地>建筑用地>水域>未利用地。(6)土地利用对干旱指数平均值的影响非常微弱,干旱指数的变化主要是由于气候变化导致的。%Based on the remote sensing images, meteoroLogicaL and Land use data of the Wudinghe River basin during 1982-2010, we used PriestLey-TayLor formuLa to caLcuLate potentiaL evapotranspiration, then got aridity index of this period. With overLaying the meteoroLogicaL factors and aridity index difference, pixeL-by-correLation anaLysis, the aridity index variations over spatiaL and tempo-raL in the study area during this period were anaLyzed, and the infLuence of the cLimate and Land use variations on the aridity in-dex changes was studied. The resuLts show that: (1) The aridity indexes of the year 1982 and 2010 were 2.01and 2.13 respectiveLy. The trend was drought; (2) There was a rapid decLine in the regionaL aridity index of 2.0 or Less, whiLe a significant expansion of the area above 2.15; (3) It showed an increasing trend with the aridity index, a significant increase in the region focused on the middLe reaches and

  4. 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

  5. Oils and rubber from arid land plants

    Science.gov (United States)

    Johnson, J. D.; Hinman, C. W.

    1980-05-01

    In this article the economic development potentials of Cucurbita species (buffalo gourd and others), Simmondsia chinensis (jojoba), Euphorbia lathyris (gopher plant), and Parthenium argentatum (guayule) are discussed. All of these plants may become important sources of oils or rubber.

  6. Organic Matter and Water Addition Enhance Soil Respiration in an Arid Region

    OpenAIRE

    Liming Lai; Jianjian Wang; Yuan Tian; Xuechun Zhao; Lianhe Jiang; Xi Chen; Yong Gao; Shaoming Wang; Yuanrun Zheng

    2013-01-01

    Climate change is generally predicted to increase net primary production, which could lead to additional C input to soil. In arid central Asia, precipitation has increased and is predicted to increase further. To assess the combined effects of these changes on soil CO2 efflux in arid land, a two factorial manipulation experiment in the shrubland of an arid region in northwest China was conducted. The experiment used a nested design with fresh organic matter and water as the two controlled par...

  7. Land use

    International Nuclear Information System (INIS)

    Justification for large land holdings at the Hanford Reservation has centered around a need for security and also as a buffer zone in the event of accidents. In recent years the importance of these large land holdings have become nationally recognized as highly desirable locations for ecological research concerning the function and structure of terrestrial ecosystems and as places to investigate the response of terrestrial ecosystems to long-term man-imposed environmental stresses. Carefully selected and protected land areas exist on the 110 square mile Arid Land Ecology Reserve (ALE) at Hanford. The projects described here provide supporting research for several applied projects that deal with environmental impact and land restoration. Information gained from this research has wide use and applicability to all kinds of energy technologies centered in the semi-arid shrub-steppe region of the northwestern United States. Ecological information reported includes: biotic characterization, including description of major habitats and endangered or threatened species; performances of native plant species, including determination of growth habits, nutrient requirements, and productivity; and, mineral cycling, including particularly the estimation of availability and behavior of airborne deposits to green plants

  8. Impact of grazing on range plant community components under arid Mediterranean climate in northern Syria

    NARCIS (Netherlands)

    Niane, A.A.

    2013-01-01

    Keywords: Rotational grazing, full protection, continuous grazing species richness, species diversity, soil seed bank, Bayesian methods, Salsola vermiculata, seed longevity, rangeland management, Syria.   Rangelands represent 70% of the semi-arid and arid Mediterranean land mass. It is a n

  9. CHARACTERISTICS OF ARIDITY CONDITIONS IN SOUTH DOBRUDJA

    Directory of Open Access Journals (Sweden)

    A. TISCOVSCHI

    2013-04-01

    Full Text Available Characteristics of Aridity Conditions in South Dobrudja. For most people, the arid and semi-arid lands are those where precipitation is low (less than 200 mm per year, and yet enough for supplying streams capable of temporarily carrying the debris resulted from weathering, but insufficient for encouraging the development of a vegetal cover meant to protect the soil blanket against eroding agents. The drought is a major and permanent climatic risk for the Dobrudja territory as a whole and for South Dobrudja in particular, a territory where hydrographic network is underdeveloped, streams are ephemeral, and semi-endorheic areas are well developed. When the period of moisture deficiency lasts longer, it can bring about a significant water imbalance, which results in crop losses or restrictions in water consumption, thus leading to a number of economic problems. Under the circumstances, the risk of aridity expansion is significant, this being the reason why a better water management system in Romania is urgently needed. In the last decades, the numerous specialty studies undertaken in the area have emphasized an intensification of the process of dryness, because atmospheric and pedological droughts have become more and more serious. Romania is a member of the United Nations Convention to Combat Desertification (UNCCD and the World Meteorological Organization (WMO. It actively participates within the drought management network and the Drought Management Center for Southeastern Europe, which comprises 11 countries. The scope is to work together and exchange experience with the neighboring countries that have recorded positive results and acquired a rich experience in terms of drought management. The employment of appropriate pluvial indices in identifying the areas prone to aridity may prove to be convenient tool for finding practical solutions meant to mitigate the impact of this phenomenon on the local communities living in South Dobrudja.

  10. Aridity under conditions of increased CO2

    Science.gov (United States)

    Greve, Peter; Roderick, Micheal L.; Seneviratne, Sonia I.

    2016-04-01

    A string of recent of studies led to the wide-held assumption that aridity will increase under conditions of increasing atmospheric CO2 concentrations and associated global warming. Such results generally build upon analyses of changes in the 'aridity index' (the ratio of potential evaporation to precipitation) and can be described as a direct thermodynamic effect on atmospheric water demand due to increasing temperatures. However, there is widespread evidence that contradicts the 'warmer is more arid' interpretation, leading to the 'global aridity paradox' (Roderick et al. 2015, WRR). Here we provide a comprehensive assessment of modeled changes in a broad set of dryness metrics (primarily based on a range of measures of water availability) over a large range of realistic atmospheric CO2 concentrations. We use an ensemble of simulations from of state-of-the-art climate models to analyse both equilibrium climate experiments and transient historical simulations and future projections. Our results show that dryness is, under conditions of increasing atmospheric CO2 concentrations and related global warming, generally decreasing at global scales. At regional scales we do, however, identify areas that undergo changes towards drier conditions, located primarily in subtropical climate regions and the Amazon Basin. Nonetheless, the majority of regions, especially in tropical and mid- to northern high latitudes areas, display wetting conditions in a warming world. Our results contradict previous findings and highlight the need to comprehensively assess all aspects of changes in hydroclimatological conditions at the land surface. Roderick, M. L., P. Greve, and G. D. Farquhar (2015), On the assessment of aridity with changes in atmospheric CO2, Water Resour. Res., 51, 5450-5463

  11. Simulation of water use and herbage growth in arid regions

    NARCIS (Netherlands)

    Keulen, van H.

    1975-01-01

    The and and semi-arid regions of the world, totalling about 30% of the land surface of the earth, are predominantly used for extensive grazing, as low and erratic rainfall presents too high a risk for arable farming. The population that can be sustained by the animal products -meat, milk or wool- is

  12. 干旱区典型绿洲土地利用动态变化分析——以且末绿州为例%Analysis on Dynamic Change of Land Use in Typical Arid Region Oasis -- A Case Study of Qerqen Oasis

    Institute of Scientific and Technical Information of China (English)

    努尔比娅·乌斯曼; 李新国; 吐尔逊古丽·托合提; 吐尔逊·艾山乳

    2011-01-01

    文章以干旱区典型的条带状绿洲一且末绿洲为例,以1972年MSS、1990年TM、2000年和2005年ETM+遥感影像为数据源.结合野外考察数据,选择适宜的分类指标体系,对遥感图像进行了监督分类,并获得了研究区土地利用/覆盖转移矩阵。研究结果表明,近33年来耕地面积一直呈现出增加的趋势,增加了92.588km^2,耕地面积的增加量主要是由草地和林地的转化而来,是增加最快的土地利用类型;林地和草地面积一直呈逐渐减少的趋势,其中减少最多的土地类型是林地,减少了65.641km^2,林地面积的减少由林地转移草地、水体和耕地的比例超过草地转移林地的比例而引起;草地面积减少了62.01km^2,这主要是由一部分草地转移耕地、一部分转移未利用地而引起;水域面积总体上有增加趋势,增加了22.073km^2,这主要由草地和未利用地转移水体而引起;未利用地变化幅度不大,有缓慢增加的趋势,增加了13.105km^2。%Qerqan Oasis-a typical Oasis in arid area was chosen as an example, the remote sensing images of MSS in 1972, TM in 1990, ETM+ in 2000 and 2005 were used as major data sources, be combined with fieldwork data, the appropriate disaggregated indicators system was selected to classify the images, and classified the images, and then obtained the different types of land use / cover transition matrix. The results showed that the cultivated area had been showing an increasing trend in the last 33 years, it was increased 92. 588km^2 , the increase of the cultivated land is mainly from the conversion of grassland and woodland, the cultivated land is the fastest growing land use type. Woodland and grassland had been gradually decreasing trend, and most reduced land type was the forest land, it was decreased 65. 641km^2. This was mainly caused by the conversion proportion area of woodland to the grassland,water land and

  13. 应用空间技术研究干旱和半干旱地区由盐化作用造成的土地退化%Land Degradation Due to Salinization in Arid and Semi-arid Regions with the Aid of Geo-information Techniques

    Institute of Scientific and Technical Information of China (English)

    Mushtak T.Jabbar; 陈晓玲

    2008-01-01

    This study applied a computerized parametric methodology to monitor, map, and quantify land degradation by salinization risk detection techniques at a 1: 250000 mapping scale using geo-information technology. The northern part of the Shaanxi province in China was taken as a case. Multi-temporal remotely sensed materials of both Landsat TM and thematic maps (ETM+) were used as the bases to provide comprehensive views of surface conditions such as vegetation cover and salinization detection. With ERDAS ver. 9.1 software, the Normalized Differential Salinity Index (NDSI) and Salinity Index (S. I.) were computed and then evaluated for land degradation by salinization. Arc/Info ver. 9.2 software was used along with field observation data (GPS) for analysis. Using spatial analysis methods, results showed that 19973.1km2 (72%) of land had no risk of land degradation by salinization, 3684.7km2 (13%) had slight land degradation by salinization risk, 2797.9km2 (10%) had moderate land degradation by salinization risk, and 1218.9km2 (4%) of the total land area was at a high risk of land degradation by salinization. The study area, in general, is exposed to a high risk of soil salinization.

  14. 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.

  15. 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 ...

  16. Spatial distribution and comparison of aridity indices in Extremadura, southwestern Spain

    Science.gov (United States)

    Moral, Francisco J.; Rebollo, Francisco J.; Paniagua, Luis L.; García-Martín, Abelardo; Honorio, Fulgencio

    2015-09-01

    In semi-arid lands with warm climates, aridity is a real hazard, with the threat of desertification because of greater precipitation variability and prolonged droughts. Aridity indices can be used to identify areas prone to desertification. The present study aimed to analyse the spatial distribution of aridity in Extremadura, southwestern Spain, using three indices: the De Martonne aridity index (I DM), the Pinna combinative index (I P), and the Food and Agriculture Organization (FAO) aridity index (I F). Temperature, precipitation, and evapotranspiration data from 90 weather stations located throughout Extremadura and 27 along boundaries with at least 30-year length (within the 1980-2011 period) were used to compute each index at each station. The statistical properties of each aridity index were assessed, and later, they were mapped by means of an integrated geographic information system (GIS) and a multivariate geostatistical (regression-kriging) algorithm in which exhaustive secondary information on elevation was incorporated. Annual and seasonal I DM and I F, and annual I P-kriged maps were generated. According to annual I DM, the semi-arid and Mediterranean conditions are predominant in the region, covering about 70 % of the territory, while about 94 % of the areas are classified as dry and semi-dry Mediterranean based on annual I P and about 86 % are classified as semi-arid and dry categories based on annual I F. The most vulnerable to aridity are the natural regions located to the west, the south, and the southeast of Extremadura, especially during summer, when arid conditions are found across the region. Although the three aridity indices were highly correlated, displaying similar spatial patterns, I DM was preferred because it can better discriminate different climate conditions in Extremadura.

  17. 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

  18. 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

  19. Study on Land Surface Characteristics and Its Relationship with Land Surface Thermal Environment of Typical City in Arid Region%干旱区典型城市下垫面特征及其与地表热环境的关系研究

    Institute of Scientific and Technical Information of China (English)

    买买提江·买提尼亚孜; 阿里木江·卡斯木

    2015-01-01

    Landsat TM images of August 11th, 2011 were used to acquire the abundance of impervious surface Area (ISA) and vegetation fraction (FV) information of Urumqi city’s build-up area based on Linear Spectral. Unmixing Model, and land surface temperature (LST) was retrieved using Mono-Window Algorithm of that area as well, then spatial distribution characteristics of these factors were analyzed based on hierarchical method. On basis of this, the correlation relationship between abundance of ISA, FV and LST was analyzed respectively. The results show that: (1)Linear Spectral Unmixing Model is proved to be a method with low cost and high precision in extracting ISA when using medium resolution remote sensing image in this case (RMS is 0.003, much smaller than the threshold value 0.02), and it has advantages of distinguishing urban construction land and bare soil which have similar spectral characteristics; (2) Abundance of ISA is positively correlated with LST with R square of 0.69, and FV is negatively correlated with LST with R square of 0.74; (3) Bare soil has significant influence on the formation of heat island and the surface thermal environment of cities in arid region because of extremely high LST, so reducing and changing bare soil of cities in arid region is very helpful to mitigate urban heat island effect and improve the thermal environment of the whole city.%基于2011年8月11日Landsat TM遥感影像,利用混合光谱线性分解模型提取乌鲁木齐市建成区下垫面不透水面丰度和植被覆盖度信息,利用单窗算法定量反演建成区地表温度,并通过分级方法分析两个要素的空间分布特征;在此基础上,利用回归模型对乌鲁木齐市建成区不透水面丰度、植被覆盖度与地表热环境之间的关系进行相关性分析。结果表明:(1)利用混合光谱线性分解方法,基于中等分辨率TM影像提取干旱区城市乌鲁木齐建成区不透水面,成本低,精度高

  20. 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

  1. Characteristics and laws of MODS coupling relation in arid zone under global change

    Institute of Scientific and Technical Information of China (English)

    WANG Ranghui; ZHANG Huizhi; HUANG Qing

    2006-01-01

    Global change has influenced the distribution pattern and spatio-temporal changes of resources in arid zone, and has restrained the land use and land cover change, which is shown by water-heat state, landscape structure, climate effect, and human activities. The above-mentioned characteristics have a close coupling relation with the mountain-oasisdesert system (MODS). The climate in Central Asia arid zone is warm and wet, which is different from that in northern China which takes a tendency of aridity, and the mechanism has restricted the characteristics and laws of MODS. Systematic interface characteristics and process, especially the formation,transformation and consumption laws of water resource reflect directly MODS's response to global change in arid zone. Spatio-temporal pattern, dynamic change, scale change and coupling mode of MODS reflect the ecology mechanism between the systems and within the systems.

  2. 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

  3. Impact of grazing on range plant community components under arid Mediterranean climate in northern Syria

    OpenAIRE

    Niane, A.A.

    2013-01-01

    Keywords: Rotational grazing, full protection, continuous grazing species richness, species diversity, soil seed bank, Bayesian methods, Salsola vermiculata, seed longevity, rangeland management, Syria.   Rangelands represent 70% of the semi-arid and arid Mediterranean land mass. It is a natural habitat for millions of people whose livelihood depends on animal husbandry. The revolutionary developments in the animal husbandry and veterinary medicines resulted in exponential increases in h...

  4. 宁夏干旱沙区速生杨苗圃地化学除草试验%Experiment on Chemical Weeding on Land of Fast-growing Poplar Nursery in Arid Sandy Area of Ningxia

    Institute of Scientific and Technical Information of China (English)

    张发国; 孙小华; 周维维

    2012-01-01

    对宁夏干旱沙区不同土壤类型速生杨苗圃地进行化学除草试验,结果表明,用草甘膦与施田补120倍液混配剂防除效果最好,杂草死亡率达89%~92%,持效期可达30 d,对苗木生长无不良影响,可防除多年生冰草及阔叶性杂草;其次是草甘膦120倍液,杂草死亡率88%~90%。风沙土苗圃地杂草死亡率略低于沙壤土中杂草死亡率。%An experiment on chemical weeding on different types of soil of fast growing poplar nursery in arid sandy area of Ningxia was conducted.The result showed that the control effect was best when glyphosate and Shi Tianbu 120 times solution mixture was used and weed mortality up to 89%~92% and effective duration up to 30 days.No adverse effect on seedling growth.Perennial ice grass and broadleaf weed could be weeded.The control effect was second-best when glyphosate 120 times solution was used and weed mortality up to 88%~90%.The weed mortality of Aeolian sandy soil nursery was little bit lower than that of sand loam nursery.

  5. 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.

  6. Agave Lechuguilla as a Potential Biomass Source in Arid Areas

    Directory of Open Access Journals (Sweden)

    Ahmad Houri

    2016-03-01

    Full Text Available Biomass productivity presents a challenging problem in arid and semi-arid areas.  Despite a large need for energy in the form of solid biomass, liquid fuel or needs for animal feed, these regions remain largely unproductive.  A convenient way to overcome this challenge is to utilize plants with high water-use efficiency.  Agave lechuguilla is an example of a highly productive (3.8 tons ha-1 yr-1 desert plant that holds the potential for producing biomass with minimal water resources.  For this purpose, a global suitability map has been developed showing areas where this plant can be planted, and its productivity was assessed.  A Maxent model was used and was further refined by excluding protected areas and used lands (urban, agriculture, etc...  Productivity assessment provides a good way forward for prioritizing the regional utilization of this plant.   This study provides an initial analysis for the use of arid and semi-arid regions for biomass production.  Results indicate the potential generation of 93.8 million tons per year of dry biomass if the suitable areas were fully utilized.  The analytical method can be readily applied to other potential plant species to optimize the use of certain areas.

  7. To make a land use inventory and its change with time and development. To investigate how this area in the semi-arid climate is developing, and the ecological impact with the construction of several government projects in Central Mexico

    Science.gov (United States)

    Acoustadelcampo, C. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. Comparison between ERTS-1 image scale 1:1,000,000 and CETENAL's charts scale 1:50,000 in irrigated land surface determination in one selected spot gave the following results: Surface on CETENAL's charts 129,900 Has. and arbitrarily we gave 100 percent to this value. Surface on image 122,400 Has., 94.5 percent of the first value. It is necessary to use all four bands to have optimum results on the interpretation. The Principal investigator made use of photointerpretation techniques only, mostly monoscopically.

  8. 半干旱区不同类型土地利用的蒸散量及水分收支差异分析--以通榆为例%Analysis of Evapotranspiration and Water Budget for Various Land Use in Semi-Arid Areas of Tongyu, China

    Institute of Scientific and Technical Information of China (English)

    赵钱飞; 郭维栋; 凌肖露; 刘野; 王国印; 解静

    2013-01-01

    determined to be 51.1 mm, which is 35.6%lower than that of the degraded grassland. In the growing season, the water budgets of both sites were positive. Although the water budget in the degraded grassland remained positive during the non-growing season, that in the cropland was negative. These results indicate that the cropland ecosystem, which involves a higher extent of human activities, is affected by more severe water supply issues in semi-arid areas and that land usage changes introduced by human activities aggravate aridity trends. Moreover, further analysis suggests that a positive water budget does not necessarily guarantee that the land surface includes an ample water supply. The Priestley-Taylor coefficients of both sites were determined to be far less than 1.0, which indicates that the actual evapotranspiration value did not reach the equilibrium evapotranspiration value due to limited water availability at the land surface. Therefore, the surface soil of the semi-arid area was adversely affected by an insufficient water supply. This result is illustrated by the soil texture of the semi-arid area, which is characterized by severe erosion and high porosity. Under such conditions, although the water budget is positive;however, the precipitation is likely to infiltrate to deeper soil layers that serve as groundwater storage, eventually resulting in water shortage at the shallow layer of soil.

  9. Stability measures in arid ecosystems

    Science.gov (United States)

    Nosshi, M. I.; Brunsell, N. A.; Koerner, S.

    2015-12-01

    Stability, the capacity of ecosystems to persist in the face of change, has proven its relevance as a fundamental component of ecological theory. Here, we would like to explore meaningful and quantifiable metrics to define stability, with a focus on highly variable arid and semi-arid savanna ecosystems. Recognizing the importance of a characteristic timescale to any definition of stability, our metrics will be focused scales from annual to multi-annual, capturing different aspects of stability. Our three measures of stability, in increasing order of temporal scale, are: (1) Ecosystem resistance, quantified as the degree to which the system maintains its mean state in response to a perturbation (drought), based on inter-annual variability in Normalized Difference Vegetation Index (NDVI). (2) An optimization approach, relevant to arid systems with pulse dynamics, that models vegetation structure and function based on a trade off between the ability to respond to resource availability and avoid stress. (3) Community resilience, measured as species turnover rate (β diversity). Understanding the nature of stability in structurally-diverse arid ecosystems, which are highly variable, yields theoretical insight which has practical implications.

  10. 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

  11. Land use classification in arid region based on multi-seasonal linear spectral mixture analysis and decision tree method%基于多季相光谱混合分解和决策树的干旱区土地利用分类

    Institute of Scientific and Technical Information of China (English)

    姜宛贝; 孙强强; 曲葳; 刘晓娜; 于文婧; 孙丹峰

    2016-01-01

    该文利用2015年Landsat 8多季相数据,以民勤县为例探讨了干旱区土地覆被/利用分类方法。首先进行了研究区多季相遥感数据的主成分变换,确定了Landsat OLI光谱空间的内在维数。其次通过对各季相主成分空间的分析,确定了光谱混合分解的端元类型及各自的代表性季相。获取端元光谱之后,采用全约束线性光谱混合模型分解各个季相的遥感影像,估计各端元组分占像元的面积百分比(端元丰度值)。最后利用端元丰度值的多季相估计结果,依据先验知识和训练样本建立决策树分类规则进行土地覆被/利用分类。分类方法的总体精度达到90.94%,Kappa系数为0.90。研究表明:将物理意义明确的端元丰度值作为分类变量,能够快速、有效地获取分类规则,生成树的结构简单、合理、清晰,对训练数据的依赖性较低,因此具有应用于整个旱地系统土地覆被/利用分类的潜力。%Land-cover/land-cover pattern of arid ecosystem in China, which determines ecosystem service value, is undergoing accelerated changes due to natural and anthropogenic disturbances. To provide a basis for ecosystem service assessment, in this article, we adopted 2015 multi-seasonal data of Landsat 8 for exploring the land cover/use classification method in arid region using the Minqin oasis as a case study area. We firstly conducted a principle component transform on the multi-seasonal remote data for identifying the inherent dimensionality of Landsat OLI spectral space. Then endmember classes and respective representative season were determined through the analysis of principal component feature space for each season. After extracting the endmember spectra by averaging the reflectance of 200~400 endmember pixels, fully-constrained linear spectral mixture model was performed on each seasonal image for yielding quantitative estimates of the areal abundance of

  12. 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.

  13. 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.

  14. 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…

  15. Study on retrieval model of land surface temperature in Jinghe watershed in arid region%干旱区精河流域地表温度的模型反演研究

    Institute of Scientific and Technical Information of China (English)

    王明霞; 毋兆鹏

    2014-01-01

    Based on Landsat ETM+ image data in Jinghe watershed oasis ,both methods of mono-window algorithm and single-channel algorithm were adopted to retrieve land surface temperature (LST ) in the study area ,and the compari-son between the retrieved results and MODIS temperature products (MODIS LST ) was made .The results showed :(1 ) The retrieved results from these two algorithms were similar each other in overall trend ,and the mean temperature differ-ence of the whole study area was about 2k .(2) The retrieval accuracy could be improved effectively by using modified soil-adjusted vegetation index (MSAVI ) instead of normalized differential vegetation index (NDVI ) to compute land sur-face emissivity ,and the retrieval accuracy of single-window algorithm was higher than that of single-channel algorithm . The correlation coefficients between the retrieved data of these two algorithms and MODIS LST were 0 .925 and 0 .8651 , respectively .(3) In the urban areas ,the correlation coefficient between the retrieved data of single-channel algorithm and MSAVI was 0 .8136 ,being higher than that of mono-window algorithm .Therefore ,the method of single-channel al-gorithm was more suitable for the retrieval research of LST in urban areas in large scale .%以精河流域绿洲为研究区,使用Landsat ETM+数据,采用单窗算法和普适性单通道算法对研究区地表温度进行反演,并将这两种算法的反演结果与研究区MODIS温度产品(MODIS LST )进行比较。结果表明:(1)单窗算法和普适性单通道算法反演的结果总体趋势比较接近,研究区整体的平均温度相差约2k;(2)采用改进型土壤调整植被指数(MSAVI )代替归一植被指数(NDVI )计算地表比辐射率可有效提高反演精度,并且同等条件下单窗算法的反演精度高于普适性单通道算法,两种算法的反演结果与MODIS LST的相关系数分别是0.9255和0.8651;(3)在城镇区域,普适

  16. 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

  17. On water repellency, humidity, fire, and wind erosion in arid landscapes

    Science.gov (United States)

    Studies of water repellent soils have usually focused on their effect on infiltration and runoff. In arid regions, however, the landscape is often shaped more by wind than by water, with important implications for ecology and land management. In a series of field, laboratory, and theoretical experim...

  18. Statut organique des sols en milieu aride : étude de la région de Coquimbo (Chili)

    OpenAIRE

    Soto, Gerardo

    2009-01-01

    Because of arid climate (70 mm precipitations/yr), the Coquimbo region, Chile, (30ªS), is the scene of environmental extreme contrasts. In fact, from a social point of view, this region shows the coexistence of three different kinds of arid lands : a) an irrigated agricultural sector, modern and open to international markets; b) an irrigated sector of traditional use; c) a non-irrigated sector consisting of sparse and eroded areas. The Coquimbo region is especially sensitive to any activities...

  19. Propágulos de fungos micorrízicos arbusculares em solos deficientes em fósforo sob diferentes usos, da região semi-arida no nordeste do Brasil Propagules of arbuscular mycorrhizae in p-deficient soils under different land uses, in semi-arid NE Brazil

    Directory of Open Access Journals (Sweden)

    Regina Lúcia Félix de Aguiar Lima

    2007-04-01

    Full Text Available A conversão de áreas de caatinga em agricultura e pecuária de subsistência é uma das características marcantes da região semi-árida do Nordeste do Brasil. O presente estudo investigou o efeito dessa conversão sobre os propágulos de fungos micorrízicos arbusculares (FMA em 10 locais diferentes, distribuídos nos Estados da Paraíba e de Pernambuco. Cada local consistiu de uma área de vegetação nativa (caatinga contígua com uma área cultivada, na mesma posição de encosta. Amostras de solo foram coletadas a intervalos de 20-30 m, nas profundidades de 0-7,5 e 7,5-15 cm (10 locais x 2 usos do solo x 2 profundidades com 4 pontos amostrais ao longo de uma transecção que cruzava as áreas contíguas. As raízes (The conversion of tropical dry forest into areas used for subsistence agriculture or livestock production is a common feature of the semi-arid region of NE Brazil. Our study looked into the effect of these land use changes on propagules of arbuscular mycorrhizal fungi (AMF at ten sites distributed in the states of Paraíba and Pernambuco. Each site consisted of an area under native vegetation (Dry-Forest adjacent to a cultivated area in the same slope position. Soil samples were taken at distance intervals of 20-30 m from two depths (0-7.5 and 7.5-15 cm along a transect crossing the adjacent areas (10 sites x 2 land uses x 2 depths x 4 sampling points. Roots (< 2 mm found in the soil samples (n = 160 were stained with trypan blue to assess the percentage of AMF colonization as well as the type of fungal structures. The AMF spores were separated from soil by wet sieving, incubated in iodonitrotetrazolium chloride (INT solution and counted; those stained with INT were considered viable. Soil samples were analyzed for resin-extractable P and total organic carbon (TOC. For data analysis, the 10 areas under dry forest were separated in two sub-groups: Undisturbed-Dry-Forest (UDF, n = 6 and Disturbed-Dry-Forest (DDF, n = 4, owing

  20. The Sand Land Soil System and Society

    Science.gov (United States)

    Mahjoory, R. A.

    Worldwide arid soils such as Latterites from African Savannas to the Xeralfs and Xererts of the Mediterranean Basin Ortents and Orthids of Asian Deserts are uniquely different in their strategic roles for utilizing the land in places where a delicate balance between annual climatic cycles and general trends toward desertification predominate Arid lands cover 1 3 of global land surface and contain irreplaceable natural resources with potential productivity of meeting the demands of more than two billion people and serving as sources and sinks of atmospheric CO2 to combat global warming The soil system in these arid areas are being degraded underutilized and kept in a stage of obliviousness due to inadequate public literacy and most importantly in-sufficient scientific evaluations based on pedology and soil taxonomy standards Implementation of food security projects and sustainable development programs on randomly selected sites and assessment of land degradation worldwide by powerful computers and satellite imagery techniques without field work and identification of Representative Soil Units are data producing and grant attracting but counter productive We live in a world in which there is an order out there and things are precisely measured and categorized for efficient utilization Why not the soils mainly in arid areas How we could generalize the world of soils under our feet by concept of soils are the same Expansion of educational programs quantification of multiple ecosystems within the arid regions through detailed and correlated

  1. Estimation of soil moisture-thermal infrared emissivity relation in arid and semi-arid environments using satellite observations

    Science.gov (United States)

    Grazia Blasi, Maria; Masiello, Guido; Serio, Carmine; Venafra, Sara; Liuzzi, Giuliano; Dini, Luigi

    2016-04-01

    The retrieval of surface parameters is very important for various aspects concerning the climatological and meteorological context. At this purpose surface emissivity represents one of the most important parameters useful for di fferent applications such as the estimation of climate changes and land cover features. It is known that thermal infrared (TIR) emissivity is aff ected by soil moisture, but there are very few works in literature on this issue. This study is aimed to analyze and fi nd a relation between satellite soil moisture data and TIR emissivity focusing on arid and semi-arid environments. These two parameters, together with the land surface temperature, are fundamental for a better understanding of the physical phenomena implied in the soil-atmosphere interactions and the surface energy balance. They are also important in several fi elds of study, such as climatology, meteorology, hydrology and agriculture. In particular, there are several studies stating a correlation between soil moisture and the emissivity at 8-9 μ m in desertic soils, which corresponds to the quartz Reststrahlen, a feature which is typical of sandy soils. We investigated several areas characterized by arid or semi-arid environments, focusing our attention on the Dahra desert (Senegal), and on the Negev desert (Israel). For the Dahra desert we considered both in situ, provided by the International Soil Moisture Network, and satellite soil moisture data, from ASCAT and AMSR-E sensors, for the whole year 2011. In the case of the Negev desert soil moisture data are derived from ASCAT observations and we computed a soil moisture index from a temporal series of SAR data acquired by the Cosmo-SkyMed constellation covering a period of six months, from June 2015 to November 2015. For both cases soil moisture data were related to the retrieved TIR emissivity from the geostationary satellite SEVIRI in three di erent spectral channels, at 8.7 μm, 10.8 μ m and 12 μ m. A Kalman lter

  2. Arid-zone groundwater recharge and palaeorecharge: insights from the radioisotope chlorine-36

    International Nuclear Information System (INIS)

    AGSO's collaborative 'Western water' study of groundwater resources in Aboriginal lands in the southwest Northern Territory arid zone, has applied the radioisotope 36CI and 14C to investigate the sustainability of community water supplies drawn from shallow aquifers in the Papunya-Kintore-Yuendumu area. The 36CI results have important implications for groundwater management throughout the arid zone, because substantial recharge occurs only during favourable, wet, interglacial climatic regimes. this has important implications for groundwater management in this area and elsewhere in central Australia, where most of the community water supplies depend on 'old' stored groundwater

  3. 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.

  4. 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.

  5. 光敏型高丹草在陇东旱塬的生物学特性和营养成分比较研究%Biological characteristics and nutrients of the photoperiod-sensitive Sorghum×Sudan-grass varieties in the arid land of east Gansu

    Institute of Scientific and Technical Information of China (English)

    何振富; 贺春贵; 魏玉明; 刘陇生

    2015-01-01

    We studied the biological characteristics,the change in nutritional value at different growth stages and the impact of cutting frequency on production with three photoperiod-sensitive Sorghum×Sudangrass vari-eties:Monster,Big Kahuna and BJ0603 in the arid land of east Gansu.All varieties were sown in late April and were at the heading or flowering stage when harvested in early October.Hence the reproductive growth stage was not completed.At harvest,the differences in plant height,node number,leaf number and stem diameter among varieties were not significant,but the differences in the weight of leaf and single stem (stalk and leaves) were significant.The standardised grass yield (65% moisture content)and the dry matter production under one cut in one year were higher than those under two cuts,but not significantly different,while the fresh grass pro-duction under two cuts was significantly higher.The differences in the fresh grass production,the standardised grass yield and the dry matter production were significant among varieties whether under one or two cuts,with the yield ranking:Monster>BJ0603>Big Kahuna.From the early jointing stage to the booting stage,the lev-els of crude protein (CP)and ether extract (EE)in the stem decreased,while the acid detergent fiber (ADF) and neutral detergent fiber (NDF)values increased.The crude fiber (CF)and soluble sugar levels increased and then decreased,while the crude ash content (ASH)dropped sharply and the nitrogen free extract (NFE) values first decreased and then increased.The contents of CP,ADF,NDF,ASH,NFE and soluble sugar dif-fered significantly among varieties,while no significant difference in EE and CF content was observed.Based on the variation in yield and nutrient content,the best utilisation strategy for photoperiod-sensitive Sorghum× Sudangrass was to cut once per year as silage and to harvest before the first frost.If utilized as hay or green chop,the best strategy in the arid land of east Gansu would be to

  6. Structure Optimization of Urban Industy in Arid Land Based on Water Footprint:A Case Study of Urumqi%水足迹视角下干旱区城市工业结构优化研究--以乌鲁木齐市为例

    Institute of Scientific and Technical Information of China (English)

    李啸虎; 杨德刚

    2015-01-01

    The development of urban industry in arid lands is constrained by the severe contradiction between the supply of available water and the demand for water resources, as well as increasing water pollution. We calculated the water consumption of industrial sectors from the perspective of their water footprints, and optimized the industrial structure to achieve the goals of water conservation and reduction of water pollution. These are of great significance to guarantee sustainable urban development in arid lands. In this study, we generated industrial water footprint (WFi), and multi-objective programming(MOP) models based on the concept of water footprint. Then we selected Urumqi as a case study, and estimated the water consumption of its industrial sectors using the WFi model. Based on this, we performed a cluster analysis of the industrial sectors. Finally, based on the cluster results and the industrial development plan for Urumqi, we examined the program for future industrial development using the MOP model. This study revealed the following. ①Based on the industrial added value, as well as blue and grey footprints of every industrial sector, we divided the industrial sectors into four categories. These were sectors with strong economic contribution, high water consumption, and much pollution; sectors with strong economic contribution, low water consumption, and little pollution; sectors with weak economic contribution, low water consumption, and little pollution;and sectors with weak economic contribution, high water consumption, and much pollution. ② On this basis, using the MOP model, we selected the sustainable mode as the best future program for industrial development in Urumqi. According to it, the WFi would be 3. 13×108 m3 in Urumqi in 2015, and assumes that the industrial blue water footprint would be 0. 72×108 m3 and the industrial grey water footprint would be 2. 41×108 m3. Industrial output value and added value would be 2. 34×1011RMB Yuan,1

  7. 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.

  8. On the Role of Hyper-arid Regions within the Virtual Water Trade Network

    Science.gov (United States)

    Aggrey, James; Alshamsi, Aamena; Molini, Annalisa

    2016-04-01

    Climate change, economic development, and population growth are bound to increasingly impact global water resources, posing a significant threat to the sustainable development of arid regions, where water consumption highly exceeds the natural carrying capacity, population growth rate is high, and climate variability is going to impact both water consumption and availability. Virtual Water Trade (VWT) - i.e. the international trade network of water-intensive products - has been proposed as a possible solution to optimize the allocation of water resources on the global scale. By increasing food availability and lowering food prices it may in fact help the rapid development of water-scarce regions. The structure of the VWT network has been analyzed by a number of authors both in connection with trade policies, socioeconomic constrains and agricultural efficiency. However a systematic analysis of the structure and the dynamics of the VWT network conditional to aridity, climatic forcing and energy availability, is still missing. Our goal is hence to analyze the role of arid and hyper-arid regions within the VWN under diverse climatic, demographic, and energy constraints with an aim to contribute to the ongoing Energy-Water-Food nexus discussion. In particular, we focus on the hyper-arid lands of the Arabian Peninsula, the role they play in the global network and the assessment of their specific criticalities, as reflected in the VWN resilience.

  9. Agave: a biofuel feedstock for arid and semi-arid environments

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Stephen; Martin, Jeffrey; Simpson, June; Wang, Zhong; Visel, Axel

    2011-05-31

    Efficient production of plant-based, lignocellulosic biofuels relies upon continued improvement of existing biofuel feedstock species, as well as the introduction of newfeedstocks capable of growing on marginal lands to avoid conflicts with existing food production and minimize use of water and nitrogen resources. To this end, specieswithin the plant genus Agave have recently been proposed as new biofuel feedstocks. Many Agave species are adapted to hot and arid environments generally unsuitable forfood production, yet have biomass productivity rates comparable to other second-generation biofuel feedstocks such as switchgrass and Miscanthus. Agavesachieve remarkable heat tolerance and water use efficiency in part through a Crassulacean Acid Metabolism (CAM) mode of photosynthesis, but the genes andregulatory pathways enabling CAM and thermotolerance in agaves remain poorly understood. We seek to accelerate the development of agave as a new biofuelfeedstock through genomic approaches using massively-parallel sequencing technologies. First, we plan to sequence the transcriptome of A. tequilana to provide adatabase of protein-coding genes to the agave research community. Second, we will compare transcriptome-wide gene expression of agaves under different environmentalconditions in order to understand genetic pathways controlling CAM, water use efficiency, and thermotolerance. Finally, we aim to compare the transcriptome of A.tequilana with that of other Agave species to gain further insight into molecular mechanisms underlying traits desirable for biofuel feedstocks. These genomicapproaches will provide sequence and gene expression information critical to the breeding and domestication of Agave species suitable for biofuel production.

  10. Hydrological Impacts of Land Use changes on Water Resources Management and Socio-economic Development of Upper Ewaso Ng'iro River Basin in Kenya

    NARCIS (Netherlands)

    Ngigi, S.N.

    2006-01-01

    Population pressure and depletion of natural resources are forcing land use changes that are intended to improve agricultural productivity. Farmers from high potential highlands are migrating into semi-arid lowlands in search of land and livelihoods. The semi-arid areas were primarily used for ranch

  11. SCIENCES IN COLD AND ARID REGIONS

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Aims and Scope Sciences in Cold and Arid Regions, an international Engiish-language journal, is devoted to publishing the latest research achievements on the process and the pattern of Earth surface system in cold and arid regions. Researches in cold regions 1) emphasize particularly on the cold-region-characterized physical, chemical and biological processes and their interactions, and on the response of Cryosphere to Global change and Human activities as well as its effect to environment and the acclimatizable

  12. 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...

  13. Feasibility of groundwater recharge dam projects in arid environments

    Science.gov (United States)

    Jaafar, H. H.

    2014-05-01

    A new method for determining feasibility and prioritizing investments for agricultural and domestic recharge dams in arid regions is developed and presented. The method is based on identifying the factors affecting the decision making process and evaluating these factors, followed by determining the indices in a GIS-aided environment. Evaluated parameters include results from field surveys and site visits, land cover and soils data, precipitation data, runoff data and modeling, number of beneficiaries, domestic irrigation demand, reservoir objectives, demography, reservoirs yield and reliability, dam structures, construction costs, and operation and maintenance costs. Results of a case study on more than eighty proposed dams indicate that assessment of reliability, annualized cost/demand satisfied and yield is crucial prior to investment decision making in arid areas. Irrigation demand is the major influencing parameter on yield and reliability of recharge dams, even when only 3 months of the demand were included. Reliability of the proposed reservoirs as related to their standardized size and net inflow was found to increase with increasing yield. High priority dams were less than 4% of the total, and less priority dams amounted to 23%, with the remaining found to be not feasible. The results of this methodology and its application has proved effective in guiding stakeholders for defining most favorable sites for preliminary and detailed design studies and commissioning.

  14. Aridity, desalination plants and tourism in the eastern Canary Islands

    Directory of Open Access Journals (Sweden)

    José-León García-Rodríguez

    2016-05-01

    Full Text Available The islands of Lanzarote and Fuerteventura are the easternmost of the Canary Islands, and are located on the southern edge of the temperate zone, in the subtropical anticyclone belt. With less than 150 mm of rainfall a year, they are classified as an arid zone. Their inhabitants have devised original agricultural systems to combat the aridity, although low yields have historically limited socio-economic development and population growth. These systems were used until the introduction of seawater desalination plants and the arrival of tourism in the last third of the twentieth century, which improved living standards for the local population but also led to a cultural transition. Nevertheless, these farming systems have left behind an important regional heritage, with an environmental and scenic value that has played an integral role in the latest phase of development. The systems have become a tourist attraction and have been central to the two islands being designated biosphere reserves by UNESCO. This article aims to analyse the main socioeconomic and land-use changes that have come about as a result of desalination technology.

  15. INVESTIGATION OF THE GROUNDWATER SUITABILITY FOR IRRIGATION PRACTICES IN AN ARID REGION: CASE STUDY

    OpenAIRE

    Ahmed Murad

    2014-01-01

    Groundwater is an important source of acceptable water for irrigation in the arid regions and in particular in the United Arab Emirates (UAE). Demand for groundwater is increasing in the UAE due to population growth and significant economic advancement associated with political stability. As agricultural practices are the main land use in Al Hayer area, southeast UAE, majority of extracted groundwater from major aquifer is used to meet the increasing demands of irrigation. This study is aimed...

  16. 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.

  17. The yearly amount and characteristics of deep-buried phreatic evaporation in hyper-arid areas

    OpenAIRE

    Li, H.; Wang, W; Zhan, H.; Qiu, F.; Wu, F.; Zhang, G.

    2015-01-01

    Water scarcity is the primary cause of land deterioration, so finding new available water resources is crucial to ecological restoration. We investigated a hyper-arid Gobi location in the Dunhuang Mogao Grottoes in this work wherein the burial depth of phreatic water is over 200 m. An air-conditioner was used in a closed greenhouse to condense and measure the yearly amount of phreatic evaporation (PE) from 2010 to 2015. The results show that the annual quant...

  18. Functional diversity enhances the resistance of ecosystem multifunctionality to aridity in Mediterranean drylands

    OpenAIRE

    Maestre, Fernando; Le Bagousse-Pinguet, Yoann; Quero, José; Tamme, Riin; Börger, Luca; Garcia-Gomez, Miguel; Gross, Nicolas

    2015-01-01

    We used a functional trait-based approach to assess the impacts of aridity and shrub encroachment on the functional structure of Mediterranean dryland communities (functional diversity and community-weighted mean trait values [CWM]), and to evaluate how these functional attributes ultimately affect multifunctionality (i.e., the provision of several ecosystem functions simultaneously).Shrub encroachment (the increase in the abundance/cover of shrubs) is a major land cover change that is taking...

  19. 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 ...

  20. 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

  1. 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

  2. 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.

  3. 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

  4. 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

  5. Pipeline monitoring with interferometry in non-arid regions

    Energy Technology Data Exchange (ETDEWEB)

    McCardle, Adrian; Rabus, Bernhard; Ghuman, Parwant [MacDonald Dettwiler, Richmond, BC (Canada); Freymueller, Jeff T. [University of Alaska, Fairbanks (United States)

    2005-07-01

    Interferometry has become a proven technique for accurately measuring ground movements caused by subsidence, landslides, earthquakes and volcanoes. Using space borne sensors such as the ERS, ENVISAT and RADARSAT satellites, ground deformation can be monitored on a millimeter level. Traditionally interferometry has been limited to arid areas however new technology has allowed for successful monitoring in vegetated regions and areas of changing land-cover. Analysis of ground movement of the Trans-Alaskan pipeline demonstrates how these techniques can offer pipeline engineers a new tool for observing potential dangers to pipeline integrity. Results from Interferometric Point Target Analysis were compared with GPS measurements and speckle tracking interferometry was demonstrated to measure a major earthquake. (author)

  6. Algae from the arid southwestern United States: an annotated bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, W.H.; Gaines, S.R.

    1983-06-01

    Desert algae are attractive biomass producers for capturing solar energy through photosynthesis of organic matter. They are probably capable of higher yields and efficiencies of light utilization than higher plants, and are already adapted to extremes of sunlight intensity, salinity and temperature such as are found in the desert. This report consists of an annotated bibliography of the literature on algae from the arid southwestern United States. It was prepared in anticipation of efforts to isolate desert algae and study their yields in the laboratory. These steps are necessary prior to setting up outdoor algal culture ponds. Desert areas are attractive for such applications because land, sunlight, and, to some extent, water resources are abundant there. References are sorted by state.

  7. Assessment of the desertification vulnerability of the Cappadocian district (Central Anatolia, Turkey based on aridity and climate-process system

    Directory of Open Access Journals (Sweden)

    Murat Türkeş

    2011-03-01

    Full Text Available The present study discusses climate of the Cappadocian district in Turkey on the basis of Thornthwaite’s climate classification and water budget, Erinç’s aridity index and United Nations Convention to Combat Desertification (UNCCD aridity index, along with the spatial and inter-seasonal variations of precipitation and air temperatures. Vulnerability of the Cappadocia to desertification processes was also investigated with respect to the aridity, lithology dominated by tuffs and climate-process system and present land-use features of the district. The data analysis revealed that coefficients of variation (CV of the mean and maximum temperatures are the greatest in summer and the smallest in winter. Nevşehir and Kayseri environs are the most continental parts of the Cappadocia with a high inter-annual variability and low temperatures. Cappadocia is characterized with a continental rainfall regime having a maximum precipitation in spring. Variability of summer precipitation totals is greater than that of other seasons, varying from 65.7% to 78%. The CVs of the annual precipitation totals are about 18% at north and about 20% at south. Semi-arid and dry sub-humid or semi-humid climate types prevail over Cappadocia according to Thornthwaite’s moisture and Erinç’s aridity indices. Steppe is the dominant vegetation formation with sparse dry trees. The Cappadocia is vulnerable to the desertification processes due to both natural factors (e.g. degree of aridity, climate-process system, weathering of tuffs, erosion, climate change, etc. and human-involvement (e.g. land degradation and intensive tourism, etc.. In order to mitigate desertification and to preserve the historical and cultural heritages in Cappadocia, sustainable land-use management and tourism planning applications are urgently needed.

  8. Assessment of the desertification vulnerability of the Cappadocian district (Central Anatolia, Turkey based on aridity and climate-process system

    Directory of Open Access Journals (Sweden)

    Murat Türkeş

    2011-03-01

    Full Text Available The present study discusses climate of the Cappadocian district in Turkey on the basis of Thornthwaite’s climate classification and water budget, Erinç’s aridity index and United Nations Convention to Combat Desertification (UNCCD aridity index, along with the spatial and inter-seasonal variations of precipitation and air temperatures. Vulnerability of the Cappadocia to desertification processes was also investigated with respect to the aridity, lithology dominated by tuffs and climate-process system and present land-use features of the district. The data analysis revealed that coefficients of variation (CV of the mean and maximum temperatures are the greatest in summer and the smallest in winter. Nevşehir and Kayseri environs are the most continental parts of the Cappadocia with a high inter-annual variability and low temperatures. Cappadocia is characterized with a continental rainfall regime having a maximum precipitation in spring. Variability of summer precipitation totals is greater than that of other seasons, varying from 65.7% to 78%. The CVs of the annual precipitation totals are about 18% at north and about 20% at south. Semi-arid and dry sub-humid or semi-humid climate types prevail over Cappadocia according to Thornthwaite’s moisture and Erinç’s aridity indices. Steppe is the dominant vegetation formation with sparse dry forests. The Cappadocia is vulnerable to the desertification processes due to both natural factors (e.g. degree of aridity, climate-process system, weathering of tuffs, erosion, climate change, etc. and human-involvement (e.g. land degradation and intensive tourism, etc.. In order to mitigate desertification and to preserve the historical and cultural heritages in Cappadocia, sustainable land-use management and tourism planning applications are urgently needed.

  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

    effect of aerosols at the top of atmosphere (TOA) fluxes (DRETOA), the atmospheric absorption of solar radiation (DREatmab) and the incoming and absorbed surface solar radiative fluxes (DREsurf and (DREnetsurf, respectively). The results are obtained for the period from January 2003 till December 2009, i.e. seven (7) years, on a monthly mean basis. The RTM results indicate that aerosols significantly enhance the absorbed solar radiation in the atmosphere, especially over the major deserts of Africa and Asia, by amounts ranging from 15 to 55 W/m2 (maximum values in Bodele, Sahara). On the other hand, through scattering and absorption, they decrease the surface absorption of solar radiation, by 10-45 W/m2 over the same areas, thus producing a significant surface radiative cooling. As a result of significant solar atmospheric absorption over the highly reflecting desert surface, aerosols decrease the reflected solar radiation to space, by up to 17 W m-2, producing a decrease of planetary albedo and an important planetary warming. Even larger values are obtained on a seasonal basis, while the average values of DREatmab and DREnetsurf over global land arid and semi-arid regions are equal to 8.9 and -11.3 W/m2, respectively. Significant intra- and inter-annual variations and changes of DREs are also identified.

  10. Changes in terrestrial aridity for the period 850-2080 from the Community Earth System Model

    Science.gov (United States)

    Fu, Qiang; Lin, Lei; Huang, Jianping; Feng, Song; Gettelman, Andrew

    2016-03-01

    This study examines changes in terrestrial aridity due to both natural and anthropogenic forcing for the period 850-2080 by analyzing the Community Earth System Model (CESM) Last Millennium Ensemble simulations for 850-2005 and the CESM Large Ensemble simulations for 1920-2080. We compare terrestrial aridity in the Medieval Warm Period (MWP) (950-1250) with that in the Little Ice Age (LIA) (1550-1850), present day (PD) (1950-2005) with the last millennium (LM) (850-1850), and the future (F8.5) (2050-2080) with the LM, to place anthropogenic changes in the context of changes due to natural forcings. The aridity index defined as the ratio of annual precipitation to potential evapotranspiration, averaged over land, becomes smaller (i.e., a drier terrestrial climate) by 0.34% for MWP versus LIA (MWP-LIA), 1.4% for PD versus LM (PD-LM), and 7.8% for F8.5 versus LM (F8.5-LM). The change of terrestrial-mean aridity in PD-LM and F8.5-LM due to anthropogenic forcing is thus 4 and 20 times of that from MWP-LIA due to natural forcing, respectively. It is shown that a drier climate in PD than LM is largely due to a decrease of precipitation while a drier climate in F8.5 than LM, and MWP than LIA, is mainly caused by an increase of temperature. The terrestrial-mean aridity change in PD-LM is, however, largely driven by greenhouse gas increases as in F8.5-LM. This is because anthropogenic aerosols have a small effect on terrestrial-mean aridity but at the same time they totally alter the attributions of aridity changes to meteorological variables by causing large negative anomalies in surface air temperature, available energy, and precipitation. Different from MWP-LIA and F8.5-LM, there are large spatial inhomogeneities in P/PET changes for PD-LM in both magnitudes and signs, caused by anthropogenic aerosols, greenhouse gases, and land surface changes. The changes of terrestrial-mean P and P - E (precipitation minus evaporation) for 850-2080 are also examined. The relative

  11. 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.

  12. Identifying Groundwater Recharge in Arid Regions

    Science.gov (United States)

    Thomas, B. F.; Famiglietti, J. S.

    2015-12-01

    Recharge epodicity in arid regions provides a method to estimate annual groundwater recharge given a relationship expressed as the recharge to precipitation ratio. Traditionally, in-situ observations are required to identify aquifer recharge events, while more advanced approaches such as the water-table fluctuation method or the episodic master recession method are necessary to delineate the recharge event. Our study uses the Gravity Recovery and Climate Experiment (GRACE) observations to estimate monthly changes in groundwater storage which are attributed to the combination of groundwater abstraction and episodic recharge in the arid southwestern United States. Our results illustrate the ability of remote sensing technologies to identify episodic groundwater recharge in arid regions which can be used within sustainable groundwater management frameworks to effectively manage groundwater resources.

  13. Organic matter and water addition enhance soil respiration in an arid region.

    Directory of Open Access Journals (Sweden)

    Liming Lai

    Full Text Available Climate change is generally predicted to increase net primary production, which could lead to additional C input to soil. In arid central Asia, precipitation has increased and is predicted to increase further. To assess the combined effects of these changes on soil CO2 efflux in arid land, a two factorial manipulation experiment in the shrubland of an arid region in northwest China was conducted. The experiment used a nested design with fresh organic matter and water as the two controlled parameters. It was found that both fresh organic matter and water enhanced soil respiration, and there was a synergistic effect of these two treatments on soil respiration increase. Water addition not only enhanced soil C emission, but also regulated soil C sequestration by fresh organic matter addition. The results indicated that the soil CO2 flux of the shrubland is likely to increase with climate change, and precipitation played a dominant role in regulating soil C balance in the shrubland of an arid region.

  14. The ecohydrology of the soil-vegetation system restoration in arid zones: a review

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Arid zones, which cover approximately 40 percent of the earth’s land surface, support complicated and widely varied ecological systems. As such, arid zones are an important composition of the global terrestrial ecosystem, and water is the key and abiotic lim-ited factor in ecosystem-driven processes in these areas. Ecohydrology is a new cross discipline that provides, in an objective and comprehensive manner, novel ideas and approaches to the evaluation of the interaction and feedback mechanisms involved in the soil-vegetation systems in arid zones. In addition, ecohydrology provides a theoretical basis of ecological restoration that is cen-tered on vegetation construction. In this paper, long-term monitoring and local observations in the transitional belt between a de-sertified steppe and a steppified desert at the Shapotou Desert Research and Experiment Station, Tengger Desert, in northern China, were evaluated. The primary achievements and related research progress regarding ecohydrology in arid zones were analyzed and summarized, as a keystone, and the response of soil ecohydrological processes to the changes in the species composition, structure, and function of sandland vegetation was discussed. Meanwhile, the long-term ecological effects and mechanism of regulation of vegetation on soil habitat and on water-cycling were considered. As a vital participant in the ecohydrological processes of soil-vegetation systems, the studies on biological soil crusts was also summarized, and related theoretical models of restoration based on the water balance was reviewed.

  15. Enclosing the commons: reasons for the adoption and adaptation of enclosures in the arid and semi-arid rangelands of Chepareria, Kenya.

    Science.gov (United States)

    Wairore, John N; Mureithi, Stephen M; Wasonga, Oliver V; Nyberg, Gert

    2015-01-01

    The adoption and adaptation of enclosures in the arid and semi-arid rangelands of sub-Saharan Africa is driven and sustained by a combination of factors. However, reviews indicate that these factors cannot be generalized, as they tend to be case specific. A study was therefore conducted to explore the history and reasons for enclosure establishment in Chepareria, a formerly degraded communal rangeland in north-western Kenya. While Vi-Agroforestry Organization accounting for 52.5 % was the main source of knowledge on enclosure establishment; it has now emerged that rangeland enclosures among the Pokot pastoral community existed prior to land management interventions by Vi- Agroforestry. Results indicated that there are three categories of enclosures which were established for boundary demarcation, provide grazing reserves, enable proper land management, facilitate crop cultivation in a pastoral setup and to curb land degradation. The role of self-trigger [accounting for most of the spontaneous enclosures (73.5 %)] indicates the continued establishment and expansion of areas under enclosure management as private land ownership accounting for 51.7 % of enclosure tenure continues to gain momentum in Chepareria. While rangeland enclosures in Chepareria were mainly established for boundary demarcation, to alleviate pasture scarcity and enable proper management of formerly degraded areas; they have facilitated land restoration and rehabilitation by increasing flexibility in land, fodder and livestock management amongst agro-pastoralists in Chepareria over the last three decades. To ensure that rehabilitated areas do not revert to their previously degraded state; technical interventions are needed to allow for a more intensive use of rangeland resources within enclosed areas.

  16. Land use in the karstic lands in the Mediterranean region.

    Directory of Open Access Journals (Sweden)

    Atalay Ibrahim

    1999-01-01

    Full Text Available Karstic lands have special importance in terms of soil formation and land-use. Soil appears only on the flat and slightly undulating karstic lands, while soils are found along the cracks and bedding surfaces between the layers on the hilly karst areas although these lands are rocky in appearance. Karstic lands in the hilly area are not conducive to cultivation. But rocky areas create a favourable habitat for the growth of forests except in an arid climate. Because the tree roots easily follow and develop along the cracks in the limestone. As a general rule soil erosion does not occur on sub-horizontal karst surfaces due to the fact that atmospheric waters easily infiltrate along the cracks. Natural generation of vegetation like the maquis-type occurs via the root suckers, but coniferous trees such as cedar, fir, pine through seed dispersal. The clearance of natural vegetation on the karstic lands leads to the formation of bare lands. That is why the slopes of the limestone hillsides have been converted into bare and/or rocky terrains in places where natural vegetation has been completely destroyed.

  17. 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.

  18. 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

  19. Applying animal behavior to arid rangeland mangement

    Science.gov (United States)

    Livestock production is one of many demands placed on today’s arid rangelands. Therefore, understanding plant and animal biology and their effects on biotic and abiotic landscape components is fundamental if rangelands are to remain ecologically sustainable. One limiting factor to accomplishing posi...

  20. Spatial interactions and resilience in arid ecosystems

    NARCIS (Netherlands)

    Koppel, van de J.; Rietkerk, M.

    2004-01-01

    We present a mathematical analysis of the consequences of spatial interactions between vegetation patches by means of water flow for the functioning of arid systems. Our model results suggest that spatial exchange of water improved the resilience to disturbances and increased the resistance to human

  1. Aridity and decomposition processes in complex landscapes

    Science.gov (United States)

    Ossola, Alessandro; Nyman, Petter

    2015-04-01

    Decomposition of organic matter is a key biogeochemical process contributing to nutrient cycles, carbon fluxes and soil development. The activity of decomposers depends on microclimate, with temperature and rainfall being major drivers. In complex terrain the fine-scale variation in microclimate (and hence water availability) as a result of slope orientation is caused by differences in incoming radiation and surface temperature. Aridity, measured as the long-term balance between net radiation and rainfall, is a metric that can be used to represent variations in water availability within the landscape. Since aridity metrics can be obtained at fine spatial scales, they could theoretically be used to investigate how decomposition processes vary across complex landscapes. In this study, four research sites were selected in tall open sclerophyll forest along a aridity gradient (Budyko dryness index ranging from 1.56 -2.22) where microclimate, litter moisture and soil moisture were monitored continuously for one year. Litter bags were packed to estimate decomposition rates (k) using leaves of a tree species not present in the study area (Eucalyptus globulus) in order to avoid home-field advantage effects. Litter mass loss was measured to assess the activity of macro-decomposers (6mm litter bag mesh size), meso-decomposers (1 mm mesh), microbes above-ground (0.2 mm mesh) and microbes below-ground (2 cm depth, 0.2 mm mesh). Four replicates for each set of bags were installed at each site and bags were collected at 1, 2, 4, 7 and 12 months since installation. We first tested whether differences in microclimate due to slope orientation have significant effects on decomposition processes. Then the dryness index was related to decomposition rates to evaluate if small-scale variation in decomposition can be predicted using readily available information on rainfall and radiation. Decomposition rates (k), calculated fitting single pool negative exponential models, generally

  2. Hydrological Impacts of Land Use changes on Water Resources Management and Socio-economic Development of Upper Ewaso Ng'iro River Basin in Kenya

    OpenAIRE

    Ngigi, S.N.

    2006-01-01

    Population pressure and depletion of natural resources are forcing land use changes that are intended to improve agricultural productivity. Farmers from high potential highlands are migrating into semi-arid lowlands in search of land and livelihoods. The semi-arid areas were primarily used for ranching and wildlife. Settlement of smallholder farmers has led to land sub-division and intensification of agriculture. Uncontrolled abstraction of irrigation water from rivers that serve downstream u...

  3. Analyzing Landscape Trends on Agriculture, Introduced Exotic Grasslands and Riparian Ecosystems in Arid Regions of Mexico

    Directory of Open Access Journals (Sweden)

    Romeo Mendez-Estrella

    2016-08-01

    Full Text Available Riparian Zones are considered biodiversity and ecosystem services hotspots. In arid environments, these ecosystems represent key habitats, since water availability makes them unique in terms of fauna, flora and ecological processes. Simple yet powerful remote sensing techniques were used to assess how spatial and temporal land cover dynamics, and water depth reflect distribution of key land cover types in riparian areas. Our study area includes the San Miguel and Zanjon rivers in Northwest Mexico. We used a supervised classification and regression tree (CART algorithm to produce thematic classifications (with accuracies higher than 78% for 1993, 2002 and 2011 using Landsat TM scenes. Our results suggest a decline in agriculture (32.5% area decrease and cultivated grasslands (21.1% area decrease from 1993 to 2011 in the study area. We found constant fluctuation between adjacent land cover classes and riparian habitat. We also found that water depth restricts Riparian Vegetation distribution but not agricultural lands or induced grasslands. Using remote sensing combined with spatial analysis, we were able to reach a better understanding of how riparian habitats are being modified in arid environments and how they have changed through time.

  4. 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.

  5. Improvement of Surface Albedo Simulations over Arid Regions

    Institute of Scientific and Technical Information of China (English)

    BAO Yan; L(U) Shihua; ZHANG Yu; MENG Xianhong; YANG Shengpeng

    2008-01-01

    To improve the simulation of the surface radiation budget and related thermal processes in arid regions, three sophisticated surface albedo schemes designed for such regions were incorporated into the Biosphere-Atmosphere Transfer Scheme (BATS). Two of these schemes are functions of the solar zenith angle (SZA), where the first one has one adjustable parameter defined as SZA1 scheme, and the second one has two empir-ical parameters defined as SZA2 scheme. The third albedo scheme is a function of solar angle and soil water that were developed based on arid-region observations from the Dunhuang field experiment (DHEX) (defined as DH scheme). We evaluated the performance of the original and newly-incorporated albedo schemes within BATS using the in-situ data from the Oasis System Energy and Water Cycle Field Experiment that was carried out in JinTa, Gansu arid area (JTEX). The results indicate that a control run by the original version of the BATS generates a constant albedo, while the SZA1 and SZA2 schemes basically can reproduce the observed diurnal cycle of surface albedo, although these two schemes still underestimate the albedo when SZA is high in the early morning and late afternoon, and overestimate it when SZA is low during noontime. The SZA2 scheme has a better overall performance than the SZA1 scheme. In addition, BATS with the DH scheme slightly improves the albedo simulation in magnitude as compared to that from the control run, but a diurnal cycle of albedo is not produced by this scheme. The SZAl and SZA2 schemes significantly increase the surface absorbed solar radiation by nearly 70 W m~2, which further raises the ground temperature by 6 K and the sensible heat flux by 35 W m~2. The increased solar radiation, heat flux, and temperature are more consistent with the observations that those from the control run. However, a significant improvement in these three variables is not found in BATS with the DH scheme due to the neglect of the diurnal cycle of

  6. 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.

  7. Bulk transfer coefficients of the atmospheric momentum and sensible heat over desert and Gobi in arid climate region of Northwest China

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Qiang(张强); WEI; Guoan(卫国安); HUANG; Ronghui(黄荣辉); CAO; Xiaoyan(曹晓彦)

    2002-01-01

    By utilizing the data of the intensive observation period (May-June, 2000) of Dunhuang land-surface process field experiment that belongs to "Land-atmosphere Interactive Field Experiment over Arid Region of Northwest China", the bulk momentum transfer coefficient Cd and bulk sensible heat transfer coefficient Ch between surface and atmosphere over desert and Gobi in the arid region are determined according to three different methods. The result shows that, though these bulk transfer coefficients are different, they are in the same order. Especially, the means of Cd and Ch are close. Moreover, through analyzing the wind direction, the interference of the building near the observational station with the data is eliminated. From this, the relation between the bulk transfer coefficients and the bulk Richardson number and the range of the typical values of the bulk transfer coefficients over desert and Gobi in the typical arid region are obtained.

  8. VOCs in Arid soils: Technology summary

    International Nuclear Information System (INIS)

    The Volatile Organic Compounds In Arid Soils Integrated Demonstration (VOC-Arid ID) focuses on technologies to clean up volatile organic compounds and associated contaminants in soil and groundwater at arid sites. The initial host site is the 200 West Area at DOE's Hanford site in southeastern Washington state. The primary VOC contaminant is carbon tetrachloride, in association with heavy metals and radionuclides. An estimated 580--920 metric tons of carbon tetrachloride were disposed of between 1955 and 1973, resulting in extensive soil and groundwater contamination. The VOC-Arid ID schedule has been divided into three phases of implementation. The phased approach provides for: rapid transfer of technologies to the Environmental Restoration (EM-40) programs once demonstrated; logical progression in the complexity of demonstrations based on improved understanding of the VOC problem; and leveraging of the host site EM-40 activities to reduce the overall cost of the demonstrations. During FY92 and FY93, the primary technology demonstrations within the ID were leveraged with an ongoing expedited response action at the Hanford 200 West Area, which is directed at vapor extraction of VOCs from the vadose (unsaturated) zone. Demonstration efforts are underway in the areas of subsurface characterization including: drilling and access improvements, off-gas and borehole monitoring of vadose zone VOC concentrations to aid in soil vapor extraction performance evaluation, and treatment of VOC-contaminated off-gas. These current demonstration efforts constitute Phase 1 of the ID and, because of the ongoing vadose zone ERA, can result in immediate transfer of successful technologies to EM-40

  9. 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.

  10. Distribution of Actual Evapotranspiration over Qaidam Basin, an Arid Area in China

    Directory of Open Access Journals (Sweden)

    Xiaomei Jin

    2013-12-01

    Full Text Available Evapotranspiration is a major loss flux of the water balance in arid and semi-arid areas. The estimation of actual evapotranspiration has significance for hydrological and environmental purposes. The Surface Energy Balance System (SEBS algorithm was applied to estimate actual evapotranspiration in the Qaidam Basin and its eight hydrological sub-regions, Northwest China. There were 3,036 cloud-free and atmospherically corrected MODIS satellite images from 2001 to 2011 used in the SEBS algorithm to determine the actual evapotranspiration. The result indicated that the estimated annual actual evapotranspiration of the basin increased with time and the value varied from 72.7 to 182.3 mm. SEBS estimates were 7.5% and 14.1% of observed pan evaporation over the western and eastern areas, respectively. The variation of SEBS actual evapotranspiration is influenced by climate factors, vegetation, net radiation, land cover type and water table depth. The analysis of the evaporative behavior of different land cover types in the basin presented that water bodies, marsh, and farmland had relatively higher mean actual evapotranspiration though these land cover types make up less than 3.5% of the total basin. Bare soil has very low evapotranspiration and covered almost 60% of the study area. The actual evapotranspiration was observed to be decreased with an increase of water table depth. Overall, the SEBS algorithm proved to be useful and has potential for estimating spatial actual evapotranspiration on a regional scale.

  11. Evaluation of an extreme-condition-inverse calibration remote sensing model for mapping energy balance fluxes in arid riparian areas

    OpenAIRE

    Hong, S.-H.; Hendrickx, J.M.H.; J. Kleissl; R. G. Allen; Bastiaanssen, W. G. M.; Scott, R.L.; A. L. Steinwand

    2014-01-01

    Accurate information on the distribution of the surface energy balance components in arid riparian areas is needed for sustainable management of water resources as well as for a better understanding of water and heat exchange processes between the land surface and the atmosphere. Since the spatial and temporal distributions of these fluxes over large areas are difficult to determine from ground measurements alone, their prediction from remote sensing data is ...

  12. Water-Price Differential and the Efficient Population Size and Urban-Rural Composition of a Distant, Large, Arid Island

    OpenAIRE

    Levy, Amnon; Zamani, Reza

    2004-01-01

    A low population density and a large distance from civilization centres present a high degree of isolation to the island's residents. Immigration can reduce the mental and material costs of isolation for the veteran residents, but at the expense of cultural and national cohesion and social harmony; and, in the case of an arid land, also at the expense of the amount and price of water allocated to agriculture. An expected-net-benefit-maximisation model for determining population size and its e...

  13. Development of Agricultural Recycle Economy in Arid Areas of Hexi Corridor-A Case Study of Zhangye city

    OpenAIRE

    Chen, Yu

    2010-01-01

    Taking Zhangye City as an example, the thesis analyzes the restricted factors of resources and environment confronted by the agriculture in arid area of Hexi Corridor: the first is the agricultural natural resources. The area of cultivated land decreases year by year, and there are sharp decrease of biological diversity as well as the shortage and waste of water resources; the second is the ecological environment. There are critical soil erosion, frequent natural disaster and outstanding agri...

  14. Diagnosis of GLDAS LSM based aridity index and dryland identification for socioeconomic aspect of water resources management

    Science.gov (United States)

    Ghazanfari, S.; Pande, S.; Hashemy, M.; Naseri M., M.

    2012-04-01

    Water resources scarcity plays an important role in socioeconomic aspect of livelihood pattern in dryland areas. Hydrological perspective of aridity is required for social and economic coping Strategies. Identification of dryland areas is crucial to guide policy aimed at intervening in water stressed areas and addressing its perennial livelihood or food insecurity. Yet, prevailing aridity indices are beset with methodological limitations that restrict their use in delineating drylands and, might be insuffient for decision making frameworks. Palmer's Drought Severity index (PDSI) reports relative soil moisture deviations from long term means, which does not allow cross comparisons, while UNEP's aridity index, the ratio of annual evaporative demand to rainfall supply, ignores site specific soil and vegetation characteristics that are needed for appropriate water balance assessment. We propose to refine UNEP's aridity index by accounting for site specific soil and vegetation to partition precipitation into competing demands of evaporation and runoff. We create three aridity indices at a 1 x 1 degree spatial resolution based on 3 decades of soil moisture time series from three GLDAS Land Surface Models (LSM's): VIC, MOSAIC and NOAH. We compare each LSM model aridity map with the UNEP aridity map which was created based on LSM data forcing. Our approach is to extract the first Eigen function from Empirical Orthogonal Function (EOF) analysis that represents the dominant spatial template of soil moisture conditions of the three LSM's. Frequency of non-exceedence of this dominant soil moisture mode for a location by all other locations is used as our proposed aridity index. The EOF analysis reveals that the first Eigen function explains, respectively, 33%, 43% and 47% of the VIC, NOAH and MOSAIC models. The temporal coefficients associated with the first OF (Orthogonal Function) for all three LSMS clearly show seasonality with a discrete jump in trend around the year 1999

  15. 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

  16. 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...

  17. Land Cover

    Data.gov (United States)

    Kansas Data Access and Support Center — The Land Cover database depicts 10 general land cover classes for the State of Kansas. The database was compiled from a digital classification of Landsat Thematic...

  18. Land acquisition

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of lands acquired by Neal Smith National Wildlife Refuge between 1991 and 2009. Lists of acres and locations of land acquired are provided for...

  19. 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...

  20. Mulighedernes land?

    DEFF Research Database (Denmark)

    Munck Petersen, Rikke

    2001-01-01

    Kommentar om arbejde med det åbne land i forlængelse af konfencen "Mulighedernes land" og vigtigheden af at landskabsarkitekter går aktivt ind i debatten og arbejdet med landskabets forandring i Danmark.......Kommentar om arbejde med det åbne land i forlængelse af konfencen "Mulighedernes land" og vigtigheden af at landskabsarkitekter går aktivt ind i debatten og arbejdet med landskabets forandring i Danmark....

  1. Climate change and water storage variability over an arid endorheic region

    Science.gov (United States)

    Yang, Tao; Wang, Chao; Chen, Yaning; Chen, Xi; Yu, Zhongbo

    2015-10-01

    Terrestrial Water Storage (TWS) plays an important role in regional climate and water resources management, especially in arid regions under global change context. However, serious lack of in-situ measurements in remote alpine mountains is hindering our current understanding of regional TWS change in the Tarim River Basin (TRB), a large and typical arid endorheic area in Northwest China of Central Asia. To solve the problem, four different hydrology products from the Gravity Recovery and Climate Experiment (GRACE) satellite, model simulations from Global Land Data Assimilation System (GLDAS) in conjunction with in-situ measurements, are utilized to investigate patterns and underlying causes of TWS and its component changes. An excess of precipitation over evapotranspiration (ET) plus runoff contributes to an increase of TWS. The phase of Total Soil Moisture (TSM) lags that of Snow Water Equivalent (SWE), indicating a recharge from snowmelt to TSM. Increasing TWS together with decreasing SWE resulted in an increase of subsurface water. Our results are of great value to amend basin-wide water management and conservation strategies for the similar arid regions considering climate change.

  2. Using Geo-informational System for determining land degradation processes

    Science.gov (United States)

    Mangul, I.; Mangul, S.

    The largest part of agricultural lands of the Republic of Moldova is concentrated in the arid zone Frequent droughts once in 2-4 years inflict vital causalities to agriculture of the Republic of Moldova However droughts influence doesn t only limit itself to forming production Drought after-effect is highly ruinous for water reserves industrial enterprises functioning rhythm and human health Droughts make for the drying up and crumbling of soil which is subject to excessive human influence and result in land degradation desertification Term desertification means land degradation in the droughty zones It is necessary to mention that the droughty ecosystems are extremely fragile and sensitive overexploitation Nowadays in the Republic of Moldova 33-37 of agricultural lands is eroded Republic of Moldova joined the United Nations Convention to Combat Desertification on December 24 1998 The Government of the Republic of Moldova ratified the National Action Plan to Combat Desertification in 2000 Within the framework of executing the National Action Plan by National Committee to Combat Desertification Geo-informational System on arid questions was organized In addition a lot of indexes corresponding to international standards were used for the evaluation of drought of the territory and land degradation processes Mostly this information is presented in maps erosion landslides aridity water resources A rich experience of using satellite information for determining land degradation demonstrates high effectiveness of this method Satellite

  3. Analysis list: ARID1A [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ARID1A Liver + hg19 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/ARID1A.1.tsv http://dbar...chive.biosciencedbc.jp/kyushu-u/hg19/target/ARID1A.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/AR...ID1A.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/ARID1A.Liver.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/Liver.gml ...

  4. Analysis list: ARID1B [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ARID1B Liver + hg19 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/ARID1B.1.tsv http://dbar...chive.biosciencedbc.jp/kyushu-u/hg19/target/ARID1B.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/AR...ID1B.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/ARID1B.Liver.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/Liver.gml ...

  5. Analysis list: ARID3B [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ARID3B Others + hg19 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/ARID3B.1.tsv http://dbar...chive.biosciencedbc.jp/kyushu-u/hg19/target/ARID3B.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/AR...ID3B.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/ARID3B.Others.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/Others.gml ...

  6. Analysis list: ARID2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ARID2 Liver + hg19 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/ARID2.1.tsv http://dbar...chive.biosciencedbc.jp/kyushu-u/hg19/target/ARID2.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/AR...ID2.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/ARID2.Liver.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/Liver.gml ...

  7. Water harvesting techniques for small communities in arid areas.

    Science.gov (United States)

    Yuen, E; Anda, M; Mathew, K; Ho, G

    2001-01-01

    Limited water resources exist in numerous remote indigenous settlements around Australia. Indigenous people in these communities are still living in rudimentary conditions while their urban counterparts have full amenities, large scale water supplies and behavioral practices which may not be appropriate for an arid continent but are supported by extensive infrastructure in higher rainfall coastal areas. As remote indigenous communities continue to develop, their water use will increase, and in some cases, costly solutions may have to be implemented to augment supplies. Water harvesting techniques have been applied in settlements on a small scale for domestic and municipal purposes, and in the large, broadacre farm setting for productive use of the water. The techniques discussed include swales, infiltration basins, infiltration trenches and "sand dam" basins. This paper reviews the applications of water harvesting relevant to small communities for land rehabilitation, landscaping and flood control. Landscaping is important in these communities as it provides shelter from the sun and wind, reduces soil erosion and hence reduced airborne dust, and in some cases provides food and nutrition. Case studies of water harvesting systems applied in the Pilbara Region, Western Australia for landscaping around single dwellings in Jigalong and Cheeditha, in a permaculture garden in Wittenoon and at a college and carpark in Karratha are described.

  8. Comparison modeling for alpine vegetation distribution in an arid area.

    Science.gov (United States)

    Zhou, Jihua; Lai, Liming; Guan, Tianyu; Cai, Wetao; Gao, Nannan; Zhang, Xiaolong; Yang, Dawen; Cong, Zhentao; Zheng, Yuanrun

    2016-07-01

    Mapping and modeling vegetation distribution are fundamental topics in vegetation ecology. With the rise of powerful new statistical techniques and GIS tools, the development of predictive vegetation distribution models has increased rapidly. However, modeling alpine vegetation with high accuracy in arid areas is still a challenge because of the complexity and heterogeneity of the environment. Here, we used a set of 70 variables from ASTER GDEM, WorldClim, and Landsat-8 OLI (land surface albedo and spectral vegetation indices) data with decision tree (DT), maximum likelihood classification (MLC), and random forest (RF) models to discriminate the eight vegetation groups and 19 vegetation formations in the upper reaches of the Heihe River Basin in the Qilian Mountains, northwest China. The combination of variables clearly discriminated vegetation groups but failed to discriminate vegetation formations. Different variable combinations performed differently in each type of model, but the most consistently important parameter in alpine vegetation modeling was elevation. The best RF model was more accurate for vegetation modeling compared with the DT and MLC models for this alpine region, with an overall accuracy of 75 % and a kappa coefficient of 0.64 verified against field point data and an overall accuracy of 65 % and a kappa of 0.52 verified against vegetation map data. The accuracy of regional vegetation modeling differed depending on the variable combinations and models, resulting in different classifications for specific vegetation groups.

  9. Comparison modeling for alpine vegetation distribution in an arid area.

    Science.gov (United States)

    Zhou, Jihua; Lai, Liming; Guan, Tianyu; Cai, Wetao; Gao, Nannan; Zhang, Xiaolong; Yang, Dawen; Cong, Zhentao; Zheng, Yuanrun

    2016-07-01

    Mapping and modeling vegetation distribution are fundamental topics in vegetation ecology. With the rise of powerful new statistical techniques and GIS tools, the development of predictive vegetation distribution models has increased rapidly. However, modeling alpine vegetation with high accuracy in arid areas is still a challenge because of the complexity and heterogeneity of the environment. Here, we used a set of 70 variables from ASTER GDEM, WorldClim, and Landsat-8 OLI (land surface albedo and spectral vegetation indices) data with decision tree (DT), maximum likelihood classification (MLC), and random forest (RF) models to discriminate the eight vegetation groups and 19 vegetation formations in the upper reaches of the Heihe River Basin in the Qilian Mountains, northwest China. The combination of variables clearly discriminated vegetation groups but failed to discriminate vegetation formations. Different variable combinations performed differently in each type of model, but the most consistently important parameter in alpine vegetation modeling was elevation. The best RF model was more accurate for vegetation modeling compared with the DT and MLC models for this alpine region, with an overall accuracy of 75 % and a kappa coefficient of 0.64 verified against field point data and an overall accuracy of 65 % and a kappa of 0.52 verified against vegetation map data. The accuracy of regional vegetation modeling differed depending on the variable combinations and models, resulting in different classifications for specific vegetation groups. PMID:27307276

  10. Mining the Agave Microbiome for adaptions to arid environments

    Energy Technology Data Exchange (ETDEWEB)

    Coleman-Derr, Devin; Wojke, Tanja; North, Gretchen; Partida-Martinez, Laila; DeAngeli, Kristen; Clingenpeel, Scott; Gross, Stephen; Tringe, Susannah; Visel, Axel

    2013-03-25

    A major challenge facing the biofuels industry is the identification of high-yield plant feedstocks that can be cultivated with minimal resource inputs without competing for land and water supplies with existing food crops. Recent research has demonstrated that the Agave plant, cultivated in Mexico and Southwestern United States for the production of fiber and alcohol, meets these criteria1. Agaves grow on non-arable rocky soils in regions characterized by prolonged drought and extreme temperatures, due in part to physiological adaptions that prevent excess water-loss in arid environments2. Plant-microbial symbioses can play a role in helping plants adapt to heat and drought stress, increasing the accessibility of soil nutrients, or compete with plant pathogens3. Whether agaves have similar beneficial microbe interactions in their native environment is unknown. We aim to provide a comprehensive characterization of the Agave microbiome, with the goal of identifying specific community members that may contribute to Agave biotic and abiotic stress tolerance

  11. Adaptive wetland management in an uncertain and changing arid environment

    Directory of Open Access Journals (Sweden)

    Rebekah Downard

    2014-06-01

    Full Text Available Wetlands in the arid western United States provide rare and critical migratory bird habitat and constitute a critical nexus within larger social-ecological systems (SES where multiple changing land-use and water-use patterns meet. The Bear River Migratory Bird Refuge in Utah, USA, presents a case study of the ways that wetland managers have created adaptive management strategies that are responsive to the social and hydrological conditions of the agriculture-dominated SES within which they are located. Managers have acquired water rights and constructed infrastructure while cultivating collaborative relationships with other water users to increase the adaptive capacity of the region and decrease conflict. Historically, water management involved diversion and impoundment of water within wetland units timed around patterns of agricultural water needs. In the last 20 years, managers have learned from flood and drought events and developed a long-term adaptive management plan that specifies alternative management actions managers can choose each year based on habitat needs and projected water supply. Each alternative includes habitat goals and target wetland water depth. However, wetland management adapted to agricultural return-flow availability may prove insufficient as population growth and climate change alter patterns of land and water use. Future management will likely depend more on negotiation, collaboration, and learning from social developments within the SES than strictly focusing on water management within refuge boundaries. To face this problem, managers have worked to be included in negotiations with regional water users, a strategy that may prove instructive for other wetland managers in agriculture-dominated watersheds.

  12. Chloride-mass-balance for predicting increased recharge after land-use change

    OpenAIRE

    Gee, G.W.; Z. F. Zhang; Tyler, S.W.; Albright, W.H.; Singleton, M.J.

    2004-01-01

    The chloride-mass-balance (CMB) method has been used extensively to estimate recharge in arid and semi-arid environments. Required data include estimates of annual precipitation, total chloride input (from dry fallout and precipitation), and pore-water chloride concentrations. Typically, CMB has been used to estimate ancient recharge but recharge from recent land-use change has also been documented. Recharge rates below a few mm/yr are reliably detected with CMB; however, estimates above...

  13. 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...

  14. Earth observing data and methods for advancing water harvesting technologies in the semi-arid rain-fed environments of India

    Science.gov (United States)

    Sharma, C.; Thenkabail, P.; Sharma, R. R.

    2011-01-01

    The paper develops approaches and methods of modeling and mapping land and water productivity of rain-fed crops in semi-arid environments of India using hyperspectral, hyperspatial, and advanced multispectral remote sensing data and linking the same to field-plot data and climate station data. The overarching goal is to provide information to advance water harvesting technologies in the agricultural croplands of the semi-arid environments of India by conducting research in a representative pilot site in Jodhpur, Rajasthan, India. ?? 2011 IEEE.

  15. Evaluation of MODIS LST Products Using Longwave Radiation Ground Measurements in the Northern Arid Region of China

    Directory of Open Access Journals (Sweden)

    Wenping Yu

    2014-11-01

    Full Text Available This study presents preliminary results of the validation of the Moderate Resolution Imaging Spectroradiometer (MODIS daily LST products (MOD/MYD11A1, Version 5 using longwave radiation ground measurements obtained at 12 stations in the North Arid and Semi-Arid Area Cooperative Experimental Observation Integrated Research program. In this evaluation process, the broadband emissivity at each station was obtained from the ASTER Spectral Library or estimated from the MODIS narrowband emissivity Collection 5. A comparison of the validation results based on those two methods shows that no significant differences occur in the short-term validation, and a sensitivity analysis of the broadband emissivity demonstrates that it has a limited effect on the evaluation results. In general, the results at the 12 stations indicate that the LST products have a lower accuracy in China’s arid and semi-arid areas than in other areas, with a mean absolute error of 2–3 K. Compared with the temporal mismatch, the spatial mismatch has a stronger effect on the validation results in this study, and the stations with homogeneous land cover have more comparable MODIS LST accuracies. Comparisons between the stations indicate that the spatial mismatch can increase the influence of the temporal mismatch.

  16. Reboisement des Terres Arides. (Reforestation in Arid Lands. Manual M5A). Appropriate Technologies for Development Series.

    Science.gov (United States)

    Palmer, Virginia C., Ed.

    This is the French translation for a manual which presents some current, state-of-the-art examples of forestry programs in West Africa. It is based on the collective experiences of foresters and of local farmers and herders. Since many of the problems of reforestation of dry areas are the same worldwide, the text (which focuses on the broad…

  17. 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)

  18. Reducción del Consumo Eléctrico y C0(2 mediante Sistemas de Ahorro y de Aislamiento Térmico aplicados a Viviendas en Zonas Áridas de México Electrical Consumption and C0(2 Reduction using Saving Systems and Thermal Insulation applied to Dwellings in Arid Lands of México

    Directory of Open Access Journals (Sweden)

    Roberto Calderón

    2011-01-01

    Full Text Available Se compara los consumos de energía de dos tipos de vivienda, eficiente e ineficiente, determinando su consumo eléctrico y reducción de C0(2, utilizando aislamiento térmico y sistemas de ahorro de energía. El estudio realizado mediante simulación se aplica a tres ciudades áridas de México: Mexicali, Ciudad Obregón y Hermosillo. De la vivienda ineficiente evaluada en las tres ciudades, Mexicali, registró los índices más altos con 7.014 kWh/año, impactando directamente sobre el ingreso familiar, los rangos de confort y la calidad de vida del usuario, además de aportar una cantidad de 4.88 toneladas de emisiones de C0(2 por vivienda al año. Estos indicadores pueden llegar a reducirse en entre el 40 y 50% si la vivienda es eficiente.The energy consumption of two types of dwellings, efficient and inefficient, are analyzed and compared, determining the electrical consumption and C0(2 reduction, utilizing thermal insulation and saving-energy options. The study done by simulation was applied in three arid áreas in México: Mexicali, Baja Obregón and Hermosillo. The results indícate that Mexicali presented the highest consumptions rates with 7.104 kWh/year, affecting directly the family household income, thermal comfort and life quality, besides providing 4.88 tons of C0(2 emission per house per year. These indexes can be reduced by 40 and 50% if the house is efficient.

  19. 干旱区绿洲城市土地集约利用与区域发展协调性评价--以喀什市为例%Oasis City Coordination Evaluation between Urban Intensive Land Use and Economic Society Development in Arid Area:A Case Study in Kashgar

    Institute of Scientific and Technical Information of China (English)

    哈尚辰; 阿里木江·卡斯木

    2015-01-01

    Two evaluation systems are constructed based on AHP hierarchical model:the intensive land use level e-valuation system, the intensive land use and regional development coordination evaluation system.Combined with social and economic development data in Kashgar during 2002-2011 , the intensive land use level and its effect factors in 10 years are researched by TOPSIS method.The results show that:the level of intensive land use in Kash-gar from 2002 to 2011 rises in an overall trend ( increase rate:0.021 4);the coordination degree also has an upward trend in the same period ( increase rate:0.035 4);the intensive land use and the social-economic development level are positively correlated, that is to say, intensive land use can promote the social-economic development level of Kashgar.The impact factors which influence the intensive land use and regional development coordination of Kash-gar mainly include the economic development level, population structure, social security system and environmental carrying capacity.The environmental carrying capacity is the key to improve the intensive land use and regional de-velopment coordination of Kashgar.%基于AHP层次模型构建两大评价体系:土地集约利用水平评价体系、土地集约利用与区域发展协调性评价体系,结合2002—2011年的喀什市社会经济发展数据,利用TOPSIS法研究了喀什市在这10年内的土地集约利用水平及影响因子.分析结果表明:喀什市土地集约利用水平在2002—2011年整体呈上升趋势(增率为:0.0214);喀什市土地集约利用与区域发展之间的协调程度在相同的研究期内也呈整体上升趋势(增率为:0.0354);土地集约利用与社会经济的发展水平呈正相关,即土地利用方式的集约有助于提高喀什市的社会经济发展水平;喀什市土地集约利用与区域发展协调性的主要影响因子包括城市的经济发展水平、人口结构、社会保障体

  20. Advancing the Food-Energy-Water Nexus: Closing Nutrient Loops in Arid River Corridors.

    Science.gov (United States)

    Mortensen, Jacob G; González-Pinzón, Ricardo; Dahm, Clifford N; Wang, Jingjing; Zeglin, Lydia H; Van Horn, David J

    2016-08-16

    Closing nutrient loops in terrestrial and aquatic ecosystems is integral to achieve resource security in the food-energy-water (FEW) nexus. We performed multiyear (2005-2008), monthly sampling of instream dissolved inorganic nutrient concentrations (NH4-N, NO3-N, soluble reactive phosphorus-SRP) along a ∼ 300-km arid-land river (Rio Grande, NM) and generated nutrient budgets to investigate how the net source/sink behavior of wastewater and irrigated agriculture can be holistically managed to improve water quality and close nutrient loops. Treated wastewater on average contributed over 90% of the instream dissolved inorganic nutrients (101 kg/day NH4-N, 1097 kg/day NO3-N, 656 kg/day SRP). During growing seasons, the irrigation network downstream of wastewater outfalls retained on average 37% of NO3-N and 45% of SRP inputs, with maximum retention exceeding 60% and 80% of NO3-N and SRP inputs, respectively. Accurate quantification of NH4-N retention was hindered by low loading and high variability. Nutrient retention in the irrigation network and instream processes together limited downstream export during growing seasons, with total retention of 33-99% of NO3-N inputs and 45-99% of SRP inputs. From our synoptic analysis, we identify trade-offs associated with wastewater reuse for agriculture within the scope of the FEW nexus and propose strategies for closing nutrient loops in arid-land rivers.

  1. Advancing the Food-Energy-Water Nexus: Closing Nutrient Loops in Arid River Corridors.

    Science.gov (United States)

    Mortensen, Jacob G; González-Pinzón, Ricardo; Dahm, Clifford N; Wang, Jingjing; Zeglin, Lydia H; Van Horn, David J

    2016-08-16

    Closing nutrient loops in terrestrial and aquatic ecosystems is integral to achieve resource security in the food-energy-water (FEW) nexus. We performed multiyear (2005-2008), monthly sampling of instream dissolved inorganic nutrient concentrations (NH4-N, NO3-N, soluble reactive phosphorus-SRP) along a ∼ 300-km arid-land river (Rio Grande, NM) and generated nutrient budgets to investigate how the net source/sink behavior of wastewater and irrigated agriculture can be holistically managed to improve water quality and close nutrient loops. Treated wastewater on average contributed over 90% of the instream dissolved inorganic nutrients (101 kg/day NH4-N, 1097 kg/day NO3-N, 656 kg/day SRP). During growing seasons, the irrigation network downstream of wastewater outfalls retained on average 37% of NO3-N and 45% of SRP inputs, with maximum retention exceeding 60% and 80% of NO3-N and SRP inputs, respectively. Accurate quantification of NH4-N retention was hindered by low loading and high variability. Nutrient retention in the irrigation network and instream processes together limited downstream export during growing seasons, with total retention of 33-99% of NO3-N inputs and 45-99% of SRP inputs. From our synoptic analysis, we identify trade-offs associated with wastewater reuse for agriculture within the scope of the FEW nexus and propose strategies for closing nutrient loops in arid-land rivers. PMID:27438783

  2. CHARACTERISTICS AND CONSTRUCTION OF LANDSCAPE???ECOLOGY IN ARID REGIONS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper analyzes the characteristics of the landscape structures and landacape ecological processes in arid regions of China. Landscape structure is simplicity and homogeneity with the pattern of desert-oasis-river and canal corridor. The spatial distribution of landscape heterogeneity mosaics is relatively dependent on water resources. In arid regions,the landscape changes rapidly and extensively because of the sensitive landscape ecosystems and fragile regional ecosystems.For the sustainable development of arid regions, the theories and methods for the eco-environmental construction and the strategies of ecological construction in the arid regions were proposed in the view of landscape ecology. Keynote subjects of landscape ecology were also discussed. The paper points out that protecting and increasing landscape diversity and heterogeneity are critical to control ecological safety in arid regions.

  3. Analysis list: ARID3A [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ARID3A Blood,Liver + hg19 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/AR...ID3A.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/ARID3A.5.tsv http://dbarchive.biosciencedb...c.jp/kyushu-u/hg19/target/ARID3A.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/ARID3A.Blood.tsv,http://dbarchive.biosci...encedbc.jp/kyushu-u/hg19/colo/ARID3A.Liver.tsv http://dbarchive.bioscience...dbc.jp/kyushu-u/hg19/colo/Blood.gml,http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/Liver.gml ...

  4. Development of an arid site closure plan

    International Nuclear Information System (INIS)

    This document describes the development of a prototype plan for the effective closure and stabilization of an arid low-level waste disposal site. This plan will provide demonstrated closure techniques for a trench in a disposal site at Los Alamos. The accuracy of modeling soil water storage by two hydrologic models, CREAMS and HELP, was tested by comparing simulation results with field measurements of soil moisture in eight experimental landfill cover systems having a range of well-defined soil profiles and vegetative covers. Regression analysis showed that CREAMS generally represented soil moisture more accurately than HELP simulations. Precautions for determining parameter values for model input and for interpreting simulation results are discussed. A specific example is presented showing how the field-validated hydrologic models can be used to develop a final prototype closure plan. 15 refs., 13 figs., 3 tabs

  5. Nutrient and water management practices for increasing crop production in rainfed arid/semi-arid areas. Proceedings of a coordinated research project

    International Nuclear Information System (INIS)

    The world's population is expected to reach eight billion by the year 2025, putting greater pressure on world food security, especially in developing countries where major population increases is expected to occur. In meeting the increasing demand for food, rainfed agriculture will continue to play a major role. More than 65% of cereal croplands worldwide are rainfed, accounting for 58% of world cereal production. Moreover, with the decreasing availability of irrigation water for agriculture, there is an increased need for enhancing crop productivity under rainfed conditions. Currently, irrigation accounts for around 70% of water withdrawals worldwide and 90% in low-income developing countries, but due to rapidly increasing domestic and industrial demands for water in many developing countries, serious limitations to irrigated agriculture are foreseen. Increasing crop productivity in arid and semi-arid areas is widely recognized as difficult. This is mainly due to highly erratic and low rainfall as well as degraded soils deficient in plant nutrients. To meet the increasing demand for food, farmers in many developing countries have expanded rainfed agriculture into marginal lands that are susceptible to environmental degradation, particularly soil erosion. Nutrient mining is a common application of adequate amounts of fertilizers to replenish nutrient uptake by crops and losses but is not a viable option for most resource-poor farmers in these regions. As a result, crop productivity of rainfed regions is low. For example, cereal yields in rainfed areas of developing countries rarely exceed 1.5 t ha-1, less than half those of rainfed cereals in developed countries. Nevertheless, there is some evidence that crop yields in these regions can be profitably increased and yield variation decreased with a combination of careful management of natural resources and low inputs of chemical fertilizers. Since nearly two-thirds of the rural population of developing countries live

  6. Rainfall simulations as a tool for quantification of soil erosion processes caused by the trampling of sheep and goats in semi-arid and arid landscapes

    Science.gov (United States)

    Ruthenberg, Jonas; Tumbrink, Jonas; Wilms, Tobias; Peter, Klaus Daniel; Wirtz, Stefan; Ries, Johannes B.

    2015-04-01

    As there is a massive increase of livestock husbandry in semi-arid and arid landscapes, the investigation of trampling-induced soil erosion has become indispensable for a better understanding of erosive processes such as loosening and translocation of sediment, as well as the genesis of rill erosion and gully systems. Our work will support other studies focusing on desertification and land-use changes in the investigated landscapes. Up to this date, research on livestock-induced soil erosion, even in relation to other erosion processes such as aeolian and fluvial/pluvial sediment translocation, is very scarcely found in literature. The presented study on trampling-induced soil erosion by sheep and goats in arid and semi-arid landscapes aims to create a general understanding, an estimation and quantification of the influencing factors of these erosive processes. Within this study, we present the first results of several field rainfall experiments on rock fragment translocation as well as loosening and transportation of coarse and fine sediment depending on the motion sequence and the individual weight, size, and hoof beat of the animals. Furthermore, we conducted additional experiments to investigate the trampling-induced erosion processes for various other sediments, especially those in the range of clay, silt, and sand. To do so, we used a specially designed test plot, equipped with sediment traps on each side. For a clear and reliable analysis of the measured parameters, univariate as well as multivariate statistical methods have been used. For all field methods, we developed relevant statements concerning flock size. The rock fragment translocation experiments done so fare have shown that a flock of 45 sheep or goats moved 87 % of 320 spread out rock fragments with a mean translocation distance of 0.123 m when trampling across a test plot of 3.2 m^2. Besides that we found out that the soil surface was worked up in a way that the loosened fine sediment proved to

  7. Long-term aridity changes in the western United States.

    Science.gov (United States)

    Cook, Edward R; Woodhouse, Connie A; Eakin, C Mark; Meko, David M; Stahle, David W

    2004-11-01

    The western United States is experiencing a severe multiyear drought that is unprecedented in some hydroclimatic records. Using gridded drought reconstructions that cover most of the western United States over the past 1200 years, we show that this drought pales in comparison to an earlier period of elevated aridity and epic drought in AD 900 to 1300, an interval broadly consistent with the Medieval Warm Period. If elevated aridity in the western United States is a natural response to climate warming, then any trend toward warmer temperatures in the future could lead to a serious long-term increase in aridity over western North America.

  8. 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.

  9. Federal Lands

    Data.gov (United States)

    Department of Homeland Security — This map layer consists of federally owned or administered lands of theUnited States, Puerto Rico, and the U.S. Virgin Islands. Only areas of 640 acres or more are...

  10. Assessment of the Consistency among Precipitation Products over Arid Regions

    Science.gov (United States)

    Ghebreyesus, Dawit; Temimi, Marouane

    2016-04-01

    This study addresses the analysis of the consistency among global precipitation products over arid regions. First, precipitation products were examined against in situ observations from the UAE network. Then, the consistency among the different products was assessed regionally over the Arabian Peninsula and the Sahara Desert. Four distinct independently-derived precipitation products, namely, Global Precipitation Climate Center (GPCC), Willmott-Matsuura 2001 (WM), Tropical Rainfall Measurement Mission (TRMM), and CPC Morphing (CMORPH) were examined. Over the UAE, in situ monthly observations from 6 stations over a time period of 11 years, from 2000 to 2010 inclusive, were used. The correlation with in situ observations, Root Mean Square Error (RMSE), and Relative Bias (rBIAS) were calculated to evaluate the precipitation products. The lowest areal averaged RMSE over all stations, ranging from 3.82mm to 9.98mm, was obtained with the GPCC indicating a higher agreement with in situ observations. The average RMSE of GPCC over the country was 6.18mm. However, the highest areal averaged RMSE, ranging from 9.44 to 19.52mm, was obtained with the WM product with average of 13.57mm. The results showed an overestimation of the observed rainfall values across all products with overall average of 42%. CMORPH product was found to be the most inconsistent products spatially across the UAE with rBIAS ranging from -47% in Al Ain to 372% in Dubai. The correlation with in situ observations was found to be higher with GPCC product ranging from 0.8450 to 0.9494. TRMM was second with an average of 0.8413, ranging from 0.7098 to 0.9248. Furthermore, Mean Relative Difference (MRD) was calculated to investigate the precision among the precipitation products. CMORPH was found to be inconsistent spatially being the lowest estimator for four stations (Adu Dhabi, Al Ain, Sharjah, Ras Al Khaimah) whereas being the highest estimator for the rest two stations (Dubai and Fujairah). Generally, the

  11. Land use/land cover change and their effects on landscape patterns in the Yanqi Basin, Xinjiang (China).

    Science.gov (United States)

    Wang, Shuixian; Wang, Shengli

    2013-12-01

    Human modification of land use and land cover change (LUCC) drives the change of landscape patterns and limits the availability of products and services for human and livestock. LUCC can undermine environmental health. Thus, this study aimed to develop an understanding of LUCC in the Yanqi Basin, Xinjiang, China, an arid area experiencing dramatic water and land resource use. A time series of satellite images (1964, 1973, 1989, 1999, and 2009) were used to calculate the index of landscape patterns to study the processes involved in changes to land uses and landscape patterns and the influence of this changes on landscape patterns. The results show that land uses in the Yanqi Basin have changed dramatically since 1964 with grassland being mainly converted to cropland. Landscape fragmentation and diversity have decreased in the study area, although landscape fragmentation increased from 1964 to 1999 and then decreased by 2009. The index of landscape diversity decreased from 1.64 in 1964 to 0.71 in 2009. The heterogeneity and complexity of the landscape increased during this period. In contrast, the index of dominance decreased from 0.85 in 1964 to 0.83 in 2009. Land use change drives landscape patterns of the development of the watershed toward diversity and a fragmented structure. Population growth, economic development, and industrial policies were the dominant driving forces behind LUCC in the Yanqi Basin. Sustainable use of land resources is a significant factor in maintaining economic development and environmental protection in this arid inland river basin.

  12. 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.

  13. 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.

  14. Aridity changes in the Tibetan Plateau in a warming climate

    International Nuclear Information System (INIS)

    Desertification in the Tibetan Plateau (TP) has drawn increasing attention in the recent decades. It has been postulated as a consequence of increasing climate aridity due to the observed warming. This study quantifies the aridity changes in the TP and attributes the changes to different climatic factors. Using the ratio of precipitation to potential evapotranspiration (P/PET) as an aridity index, we used observed meteorological records at 83 stations in the TP to calculate PET using the Penman–Monteith algorithm and the ratio. Spatial and temporal changes of P/PET in 1979–2011 were analyzed. Results show that stations located in the arid and semi-arid northwestern TP are becoming significantly wetter, and half of the stations in the semi-humid eastern TP are becoming drier, though not significantly, in the recent three decades. The aridity change patterns are significantly correlated with the change patterns of precipitation, sunshine duration and diurnal temperature range. Temporal correlations between the annual P/PET ratio and other meteorological variables confirm the significant correlation between aridity and the three variables, with precipitation being the dominant driver of P/PET changes at the interannual time scale. Annual PET are insignificantly but negatively correlated with P/PET in the cold season. In the warm season, however, the correlation between PET and P/PET is significant at the confidence level of 99.9% when the cryosphere near the surface melts. Significant correlation between annual wind speed and aridity occurs in limited locations and months. Consistency in the climatology pattern and linear trends in surface air temperature and precipitation calculated using station data, gridded data, and nearest grid-to-stations for the TP average and across sub-basins indicate the robustness of the trends despite the large spatial heterogeneity in the TP that challenge climate monitoring. (letter)

  15. Land institutions and land markets

    OpenAIRE

    Deininger, Klaus; Feder, Gershon

    1998-01-01

    In agrarian societies land serves as the main means not only for generating a livelihood but often also for accumulating wealth and transferring it between generations. How land rights are assigned therefore determines households'ability to generate subsistence and income, their social and economic status (and in many cases their collective identity), their incentive to exert nonobservable effort and make investments, and often their ability to access financial markets or to make arrangements...

  16. Late glacial aridity in southern Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Davis, O.K.; Pitblado, B.L. [Univ. of Arizona, Tucson, AZ (United States)

    1995-09-01

    While the slopes of the present-day Colorado Rocky Mountains are characterized by large stands of subalpine and montane conifers, the Rockies of the late glacial looked dramatically different. Specifically, pollen records suggest that during the late glacial, Artemisia and Gramineae predominated throughout the mountains of Colorado. At some point between 11,000 and 10,000 B.P., however, both Artemisia and grasses underwent a dramatic decline, which can be identified in virtually every pollen diagram produced for Colorado mountain sites, including Como Lake (Sangre de Cristo Mountains), Copley Lake and Splains; Gulch (near Crested Butte), Molas Lake (San Juan Mountains), and Redrock Lake (Boulder County). Moreover, the same pattern seems to hold for pollen spectra derived for areas adjacent to Colorado, including at sites in the Chuska Mountains of New Mexico and in eastern Wyoming. The implications of this consistent finding are compelling. The closest modem analogues to the Artemisia- and Gramineae-dominated late-glacial Colorado Rockies are found in the relatively arid northern Great Basin, which suggests that annual precipitation was much lower in the late-glacial southern Rocky Mountains than it was throughout the Holocene.

  17. 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)

  18. Reduce land degradation, climate change and adaptation measures

    International Nuclear Information System (INIS)

    The land degradation and desertification are a serious threat to the sustainability of production food in many areas of the Earth. the methods ecosystems and the concomitant effects management of climate change are altering the processes physical, chemical and biological processes that regulate the complex balance of terrestrial ecosystems and soil particularly in areas climatically characterized by conditions arid, semi-arid and dry sub humid areas. The RIO + 20 Conference has recognized the risk of desertification and it proposed for the post 2015 agenda the goal of a world 'Land Degradation Neutral'.The challenge of adaptation to changes climate will require a greater involvement scientific research in support of conservation and use of natural resources both in Italy and in all contexts where the challenge of sustainability of development is more urgent.

  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. Simulated responses of terrestrial aridity to black carbon and sulfate aerosols

    Science.gov (United States)

    Lin, L.; Gettelman, A.; Xu, Y.; Fu, Q.

    2016-01-01

    Aridity index (AI), defined as the ratio of precipitation to potential evapotranspiration (PET), is a measure of the dryness of terrestrial climate. Global climate models generally project future decreases of AI (drying) associated with global warming scenarios driven by increasing greenhouse gas and declining aerosols. Given their different effects in the climate system, scattering and absorbing aerosols may affect AI differently. Here we explore the terrestrial aridity responses to anthropogenic black carbon (BC) and sulfate (SO4) aerosols with Community Earth System Model simulations. Positive BC radiative forcing decreases precipitation averaged over global land at a rate of 0.9%/°C of global mean surface temperature increase (moderate drying), while BC radiative forcing increases PET by 1.0%/°C (also drying). BC leads to a global decrease of 1.9%/°C in AI (drying). SO4 forcing is negative and causes precipitation a decrease at a rate of 6.7%/°C cooling (strong drying). PET also decreases in response to SO4 aerosol cooling by 6.3%/°C cooling (contributing to moistening). Thus, SO4 cooling leads to a small decrease in AI (drying) by 0.4%/°C cooling. Despite the opposite effects on global mean temperature, BC and SO4 both contribute to the twentieth century drying (AI decrease). Sensitivity test indicates that surface temperature and surface available energy changes dominate BC- and SO4-induced PET changes.

  1. Landscape eco-environment risk assessment of highway in arid area of Xinjiang,China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    With the aid of analyses to landscape ecology in the highway region of the arid area in Xinjiang of China, vegetation type, soil type and land-use type were ascertained as environmental factors of highway landscape ecosystem fragility, and seasonal flood, blown-wind sand and alkali-salinization as disaster factors of highway engineering. All items of these factors constitute an objective hierarchy of evaluating landscape ecosystem risk of the highway region in the arid area. The weighted values of the items were determined according to the number of occupied area or length by them against each unit. The area or length was interpreted with the aids of GIS technology and gained by measuring in the highway reconnaissance. The results of the eco-environmental risk assessment of G315 Yitunbulake-Qiemo section in Xinjiang shows that eight units of landscape ecology can be sorted into four categories according to the differences of the fragility indices (Σxiwi) and the disaster indices (Σyiwj).

  2. Effects of aridity in controlling the magnitude of runoff and erosion after wildfire

    Science.gov (United States)

    Noske, Philip J.; Nyman, Petter; Lane, Patrick N. J.; Sheridan, Gary J.

    2016-06-01

    This study represents a uniquely high-resolution observation of postwildfire runoff and erosion from dry forested uplands of SE Australia. We monitored runoff and sediment load, and temporal changes in soil surface properties from two (0.2-0.3 ha) dry forested catchments burned during the 2009 Black Saturday wildfire. Event-based surface runoff to rainfall ratios approached 0.45 during the first year postwildfire, compared to reported values runoff ratios in these dry forests were attributed to wildfire-induced soil water repellency and inherently low hydraulic conductivity. Mean ponded hydraulic conductivity ranged from 3 to 29 mm h-1, much lower than values commonly reported for wetter forest. Annual sediment yields peaked at 10 t ha-1 during the first year before declining dramatically to background levels, suggesting high-magnitude erosion processes may become limited by sediment availability on hillslopes. Small differences in aridity between equatorial and polar-facing catchments produced substantial differences in surface runoff and erosion, most likely due to higher infiltration and surface roughness on polar-facing slopes. In summary, the results show that postwildfire erosion processes in Eucalypt forests in south-east Australia are highly variable and that distinctive response domains within the region exist between different forest types, therefore regional generalizations are problematic. The large differences in erosion processes with relatively small changes in aridity have large implications for predicting hydrologic-driven geomorphic changes, land degradation, and water contamination through erosion after wildfire across the landscape.

  3. Simulating Water Flow and Heat Transfer in Arid Soil Using Weighing Lysimeter Data

    Science.gov (United States)

    Dijkema, Jelle; Koonce, Jeremy; Ghezzehei, Teamrat; Berli, Markus; van der Ploeg, Martine; (Rien) van Genuchten, Martinus

    2015-04-01

    Deserts cover about one third of the Earth's land surface. Rather little though is known about the physics of desert soils and their implications for the ecology and hydrology of arid environments. The recently constructed weighing lysimeters located in Boulder City, Nevada, were designed to improve our understanding of the physical processes and properties of arid soils at the meter scale. In this study, we developed a HYDRUS-1D model to simulate water infiltration, hydraulic redistribution, and heat transfer for one of the lysimeters. HYDRUS-1D solves the coupled equations for water flow and heat transfer in variably saturated soil. Soil hydraulic and thermal properties were initialized based on prior knowledge and characterizations of the lysimeter soil. Soil hydraulic and thermal parameters were further refined by inverse simulation using a subset of the soil water content, water potential and temperature measurements at various depths. The model was validated using a separate portion of the soil moisture and temperature data set that was not used for calibration. The calibrated model provides a tool to virtually test future experiments in the lysimeters such as changes in the irrigation regime or the incorporation of plants. The model will also help to assess the impact of the placement of physical structures (such as solar panels) on the water and heat balance of desert soils.

  4. Global distribution of minerals in arid soils as lower boundary condition in dust models

    Science.gov (United States)

    Nickovic, Slobodan

    2010-05-01

    Mineral dust eroded from arid soils affects the radiation budget of the Earth system, modifies ocean bioproductivity and influences human health. Dust aerosol is a complex mixture of minerals. Dust mineral composition has several potentially important impacts to environment and society. Iron and phosphorus embedded in mineral aerosol are essential for the primary marine productivity when dust deposits over the open ocean. Dust also acts as efficient agent for heterogeneous ice nucleation and this process is dependent on mineralogical structure of dust. Recent findings in medical geology indicate possible role of minerals to human health. In this study, a new 1-km global database was developed for several minerals (Illite, Kaolinite, Smectite, Calcite, Quartz, Feldspar, Hematite and Gypsum) embedded in clay and silt populations of arid soils. For the database generation, high-resolution data sets on soil textures, soil types and land cover was used. Tin addition to the selected minerals, phosphorus was also added whose geographical distribution was specified from compiled literature and data on soil types. The developed global database was used to specify sources of mineral fractions in the DREAM dust model and to simulate atmospheric paths of minerals and their potential impacts on marine biochemistry and tropospheric ice nucleation.

  5. Spectral Unmixing of Vegetation, Soil and Dry Carbon in Arid Regions: Comparing Multispectral and Hyperspectral Observations

    Science.gov (United States)

    Asner, Gregory P.; Heidebrecht, Kathleen B.

    2001-01-01

    Remote sensing of vegetation cover and condition is critically needed to understand the impacts of land use and climate variability in and and semi-arid regions. However, remote sensing of vegetation change in these environments is difficult for several reasons. First, individual plant canopies are typically small and do not reach the spatial scale of typical Landsat-like satellite image pixels. Second, the phenological status and subsequent dry carbon (or non-photosynthetic) fraction of plant canopies varies dramatically in both space and time throughout and and semi-arid regions. Detection of only the 'green' part of the vegetation using a metric such as the normalized difference vegetation index (NDVI) thus yields limited information on the presence and condition of plants in these ecosystems. Monitoring of both photosynthetic vegetation (PV) and non-photosynthetic vegetation (NPV) is needed to understand a range of ecosystem characteristics including vegetation presence, cover and abundance, physiological and biogeochemical functioning, drought severity, fire fuel load, disturbance events and recovery from disturbance.

  6. Downscaling MODIS-derived maps using GIS boosted regression trees : the case of frost occurrence over the arid Andean highlands of Bolivia

    OpenAIRE

    Pouteau, Robin; Rambal, Serge; Ratte, Jean-Pierre; Gogé, Fabien; JOFFRE, RICHARD; Winkel, Thierry

    2011-01-01

    International audience Frost risk assessment is of critical importance in tropical highlands like the Andes where human activities thrives at altitudes up to 4200 m, and night frost may occur all the year round. In these semi-arid and cold regions with sparse meteorological networks, remote sensing and topographic modeling are of potential interest for understanding how physiography influences the local climate regime. After integrating night land surface temperature from the MODIS satelli...

  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. Bird migration patterns in the arid southwest-Final report

    Science.gov (United States)

    Ruth, Janet M.; Felix, Rodney K.; Dieh, Robert H.

    2010-01-01

    To ensure full life-cycle conservation, we need to understand migrant behavior en route and how migrating species use stopover and migration aerohabitats. In the Southwest, birds traverse arid and mountainous landscapes in migration. Migrants are known to use riparian stopover habitats; we know less about how migrant density varies across the Southwest seasonally and annually, and how migrants use other habitat types during migratory stopover. Furthermore, we lack information about migrant flight altitudes, speeds, and directions of travel, and how these patterns vary seasonally and annually across the Southwest. Using weather surveillance radar data, we identified targets likely dominated by nocturnally migrating birds and determined their flight altitudes, speeds, directions over ground, and variations in abundance. Migrating or foraging bats likely are present across the region in some of these data, particularly in central Texas. We found that migrants flew at significantly lower altitudes and significantly higher speeds in spring than in fall. In all seasons migrants maintained seasonally appropriate directions of movement. We detected significant differences in vertical structure of migrant densities that varied both geographically within seasons and seasonally within sites. We also found that in fall there was a greater and more variable passage of migrants through the central part of the borderlands (New Mexico and west Texas); in spring there was some suggestion of greater and more variable passage of migrants in the eastern borderlands (central and south Texas). Such patterns are consistent with the existence of at least two migration systems through western North America and the use of different migration routes in spring and fall for at least some species. Using radar data and satellite land cover data, we determined the habitats with which migrants are associated during migration stopover. There were significant differences in bird densities among

  9. 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)

  10. 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

  11. Evidence of Urban-Induced Precipitation Variability in Arid Climate Regimes

    Science.gov (United States)

    Shepherd, J. Marshall

    2005-01-01

    -urban (1900-1950) Phoenix. The study hypothesis that a complex interaction between the city landscape, irrigated lands, and nearby mountains have created preferred regions for rainfall development. The study also provides early evidence that rapidly urbanizing parts of the arid Middle East may also be experiencing different precipitation regimes in response to urbanization and irrigation.

  12. Soil erosion and land degradation in the Highlands of Jordan

    Science.gov (United States)

    Khresat, Saeb

    2013-04-01

    The Highlands of Jordan has a Mediterranean type of climate characterized by hot dry summers and cold wet winters. Unsustainable land use practices, recurrent droughts and climate change are the main causes of land degradation in the Highlands area of Jordan. Unsustainable land use practices include improper plowing, inappropriate rotations, inadequate or inexistent management of plant residues, overgrazing of natural vegetation, forest cutting, land fragmentation and over-pumping of groundwater. In addition, Jordan's rapid population growth (2.8% per year) is exerting considerable pressure upon its limited arable land through uncontrolled and random urbanization activities. Water erosion is the most widespread Land degradation type in the country. It greatly increases on slopes where the vegetation cover is (seasonally) reduced. It is further aggravated by a loss of soil structure and reduced infiltration rates. Wind erosion occurs most frequently in the arid and semi-arid portions of the southern Highlands, especially in areas with sandy or loamy soils. Rangeland degradation is the second most widespread land degradation type that is driven by overgrazing. The impact of overgrazing on the vegetation is evident from the excessive uprooting of the green matter (grass and bushes), leading to reduced seeding, reduced regeneration, and the consequent loss of plant cover which make the soil more susceptible to water and wind erosion. It is estimated that about 41 percent of Jordan's total land area is characterized as degraded of which 22 percent of the total land mass is classified as moderately degraded and agricultural productivity is greatly reduced. Observed aspects of land degradation include the recession of forest areas, high rate of erosion by water (formation of rills and gullies), expansion of urbanized area, reduction in soil organic matter and soil structure deterioration. Implementation of soil erosion control measures such as contour cultivation

  13. 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.

  14. Estimating sagebrush cover in semi-arid environments using Landsat Thematic Mapper data

    Science.gov (United States)

    Sivanpillai, Ramesh; Prager, Steven D.; Storey, Thomas O.

    2009-04-01

    Sagebrush ecosystems of the western US provide important habitat for several ungulate and vertebrate species. As a consequence of energy development, these ecosystems in Wyoming have been subjected to a variety of anthropogenic disturbances. Land managers require methodology that will allow them to consistently catalog sagebrush ecosystems and evaluate potential impact of proposed anthropogenic activities. This study addresses the utility of remotely sensed and ancillary geospatial data to estimate sagebrush cover using ordinal logistic regression. We demonstrate statistically significant prediction of ordinal sagebrush cover categories using spectral ( χ2 = 113; p < 0.0001) and transformed indices ( χ2 = 117; p < 0.0001). Both Landsat spectral bands ( c-value = 0.88) and transformed indices ( c-value = 0.89) can distinguish sites with closed, moderate and open cover sagebrush cover categories from no cover. The techniques described in this study can be used for estimating categories of sagebrush cover in arid ecosystems.

  15. Shallow Horizontal GCHP Effectiveness in Arid Climate Soils

    Science.gov (United States)

    North, Timothy James

    Ground coupled heat pumps (GCHPs) have been used successfully in many environments to improve the heating and cooling efficiency of both small and large scale buildings. In arid climate regions, such as the Phoenix, Arizona metropolitan area, where the air condi-tioning load is dominated by cooling in the summer, GCHPs are difficult to install and operate. This is because the nature of soils in arid climate regions, in that they are both dry and hot, renders them particularly ineffective at dissipating heat. The first part of this thesis addresses applying the SVHeat finite element modeling soft-ware to create a model of a GCHP system. Using real-world data from a prototype solar-water heating system coupled with a ground-source heat exchanger installed in Menlo Park, California, a relatively accurate model was created to represent a novel GCHP panel system installed in a shallow vertical trench. A sensitivity analysis was performed to evaluate the accuracy of the calibrated model. The second part of the thesis involved adapting the calibrated model to represent an ap-proximation of soil conditions in arid climate regions, using a range of thermal properties for dry soils. The effectiveness of the GCHP in the arid climate region model was then evaluated by comparing the thermal flux from the panel into the subsurface profile to that of the prototype GCHP. It was shown that soils in arid climate regions are particularly inefficient at heat dissipation, but that it is highly dependent on the thermal conductivity inputted into the model. This demonstrates the importance of proper site characterization in arid climate regions. Finally, several soil improvement methods were researched to evaluate their potential for use in improving the effectiveness of shallow horizontal GCHP systems in arid climate regions.

  16. Preliminary reconstruction of the desert and sandy land distributions in China since the last interglacial period

    Institute of Scientific and Technical Information of China (English)

    CHEN Huizhong; SU Zhizhu; YANG Ping; DONG Guangrong

    2004-01-01

    The desert and sandy land are the products of arid climate. The spatial distribution of modern deserts and sandy land in China and their relation to climate show following characteristics: arid and hyper-arid desert zones, at isohyet of less than 200 mm, are dominated by mobile dunes; semi-arid steppe and arid desert steppe with the precipitation between 200-400mm, are dominated by semi-fixed and fixed sand dunes; the precipitation of sub-humid forest grassland and humid forest zones with scattered fixed sand land is higher than 400 mm. With this as reference, in combination with considerable amount of paleoclimatic data in desert regions and adjacent regions, the distributions of desert and sandy land in China during the last interglacial period, the last glacial maximum (LGM), and the Holocene megathermal, were preliminarily reconstructed. The results compared with that of today show that the distribution of desert and sandy land in China was greatly dwindled during last interglacial period, and the mobile dune area was about two-thirds of that of today's, but greatly expanded during LGM. However, the dwindling area of desert and sandy land in the Holocene megathermal was smaller than that in the last interglacial period. The forcing mechanism was mainly related to the changes of East Asian winter and summer monsoon, south-northward swing of the westerlies and the variations of the Qinghai-Tibet Plateau monsoon intensity caused by global climate changes during the cold and warm intervals since the last interglacial period.

  17. Simulation of CO2 and sensible/latent heat fluxes exchange between land surface and atmosphere over cropland and grassland in semi-arid region, China%半干旱区农田和草地与大气间二氧化碳和水热通量的模拟研究

    Institute of Scientific and Technical Information of China (English)

    姜纪峰; 延晓冬; 黄耀; 郭维栋; 刘辉志

    2007-01-01

    集成生物圈模型(IBIS)是目前最复杂的基于动态植被模型的陆面生物物理模型之一.应用该模型对国际CEOP计划半干旱区基准站之一的吉林通榆观测站(44°25'N , 122°52'E)草地和农田生态系统2003年全年的CO2和水、热通量变化进行模拟,并将结果与涡度相关法测定的观测值进行了对比分析,以检验IBIS模型在半干旱区的模拟能力.对比结果表明:除CO2通量模拟结果不够理想外,IBIS模型较好地模拟了通榆观测站的感热通量和潜热通量.总体上看,该模型对农田生态系统模拟的偏差小于对退化草地的模拟.%A comparison between simulated land surface fluxes and observed eddy covariance (EC) measurements was conducted to validate Integrated Biosphere Simulator (IBIS) at Tongyu field observation station (44°25'N, 122°52'E) in Jilin Province, China. Results showed that the IBIS model could reproduce net ecosystem CO2 exchange (NEE), sensible and latent heat fluxes reasonably, as indicated by correlation coefficients exceeding the significant level of 0.05. It was also evident that the NEE and sensible heat fluxes were characterized by diurnal and seasonal variation both in the grassland and the cropland ecosystems, while the latent heat fluxes correlated with evapotranspiration, only took on the diurnal variation during the growing season. Moreover, both sensible heat fluxes and the latent heat fluxes were larger in the cropland ecosystem than that in the degraded grassland ecosystem. This different characteristic was possibly correlated with vegetation growing situation in the two kinds of ecosystems. A close agreement between observation and simulation on NEE, sensible heat fluxes and latent heat flux was obtained both in the degraded grassland and the cropland ecosystems. In addition, the annual NEE in the model was overestimated by 23.21% at the grassland and 27.43% at the cropland, sensible heat flux with corresponding 9.90% and 11

  18. Assessment of overland flow variation and blue water production in a farmed semi-arid water harvesting catchment

    Science.gov (United States)

    Mekki, I.; Albergel, J.; Ben Mechlia, N.; Voltz, M.

    Upgrading agriculture in semi-arid areas and ensuring its sustainability require an optimal management of rainfall partition between blue and green waters in the farmed water harvesting catchment. The main objective of this study is to analyze the influence of heterogeneous land use on the spatial and temporal variation of rainfall partitioning and blue water production within a typical farmed catchment located in north-eastern Tunisia. The catchment has an area of 2.6 km 2 and comprises at its outlet a dam, which retains the runoff water in a reservoir. Overland flow and soil water balance components were monitored during two cropping seasons (2000/2001 and 2001/2002) on a network of eleven plots of 2 m 2 each with different land use and soil characteristics. The hydrological balances of both the catchment and reservoir have been monitored since 1994. Observed data showed a very large temporal and spatial variability of overland flow within the catchment reflecting the great importance of total rainfall as well as land use. During the 2001/2002 season the results showed a large variation of the number of observed runoff events, from 27 to 39, and of the annual overland flow depths, from 8 mm (under vineyard on calcaric cambisols) up to 43 mm (under shrubs-pasture on haplic regosols), between the plots. The annual runoff amounts were moderate; they always corresponded to less than 15% of the annual rainfall amount whatever the observation scale. It was also observed that changes in land use in years with similar rainfall could lead to significant differences in blue water flow. An attempt for predicting the overland flow by the general linear regression approach showed an r2 of 31%, the predictors used are the class of soil infiltration capacity, the initial moisture saturation ratio of the soil surface layer and the total rainfall amounts. These experimental results indicate that the variation in land use in a semi-arid catchment is a main factor of variation in

  19. 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

  20. Criteria for greater confinement of radioactive wastes at arid western sites

    International Nuclear Information System (INIS)

    This document provides a set of criteria and standards for greater confinement disposal (CCD) of low-level waste as an alternative to shallow land burial or deep geologic disposal for certain types of waste. The criteria and standards are discussed relative to seven major areas: radiation exposure protection, characterization of waste, transportation and handling, site selection, engineering, general facility requirements, and administration. The document addresses the objectives or goals of burial at intermediate depths to provide greater confinement, and its advantages and disadvantages compared to shallow land burial. Additionally, the document describes a generic greater confinement disposal facility (GCDF), and discusses as well as evaluates the various interrelating factors which must be considered in the selection of a viable site and in the development of GCDF design and performance criteria. Methods are developed for evaluating and ranking the importance of the factors based on health and safety, their potential impact on cost, and the uncertainty and/or difficulty in measurement and control of the factors. It also provides the methodology and analysis used to determine the various site-specific waste concentration acceptance standards (in the form of area disposal concentration limits) as well as design and engineering standards. It also illustrates the methodology used to determine the optimal or preferred depth of disposal under expected arid site conditions and alternative wet or irrigated site conditions. In addition, an example calculation demonstrates the application of the waste area concentration limits at an arid or humid GDF in determining the allowable waste inventory capacity of a particular site and the loading capacity of a waste disposal cell

  1. Extracting change information of land-use and soil-erosion based on RS & GIS technology

    Institute of Scientific and Technical Information of China (English)

    LI Zhong-feng; LI You-cai

    2007-01-01

    Rapid land-use change has taken place in many arid regions of China such as Yulin prefecture over the last decade due to rehabilitation measures. Land-use change and soil erosion dynamics were investigated by the combined use of remote sensing and geographic information systems (GIS). The objectives were to determine land-use transition rates and soil erosion change in Yulin prefecture over 15 years from 1986 to 2000. Significant changes in land-use and soil erosion occurred in the area over the study period. The results show the significant decrease in barren land mainly due to conversion to grassland. Agricultural land increased associated with conversions from grassland and barren land. The area of water erosion and wind erosion declined. The study demonstrates that the integration of satellite remote sensing and GIS is an effective approach for analyzing the direction, rate, and spatial pattern of land-use and soil erosion change.

  2. 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

  3. Carbon dioxide emissions from semi-arid soils amended with biochar alone or combined with mineral and organic fertilizers.

    Science.gov (United States)

    Fernández, José M; Nieto, M Aurora; López-de-Sá, Esther G; Gascó, Gabriel; Méndez, Ana; Plaza, César

    2014-06-01

    Semi-arid soils cover a significant area of Earth's land surface and typically contain large amounts of inorganic C. Determining the effects of biochar additions on CO2 emissions from semi-arid soils is therefore essential for evaluating the potential of biochar as a climate change mitigation strategy. Here, we measured the CO2 that evolved from semi-arid calcareous soils amended with biochar at rates of 0 and 20tha(-1) in a full factorial combination with three different fertilizers (mineral fertilizer, municipal solid waste compost, and sewage sludge) applied at four rates (equivalent to 0, 75, 150, and 225kg potentially available Nha(-1)) during 182 days of aerobic incubation. A double exponential model, which describes cumulative CO2 emissions from two active soil C compartments with different turnover rates (one relatively stable and the other more labile), was found to fit very well all the experimental datasets. In general, the organic fertilizers increased the size and decomposition rate of the stable and labile soil C pools. In contrast, biochar addition had no effects on any of the double exponential model parameters and did not interact with the effects ascribed to the type and rate of fertilizer. After 182 days of incubation, soil organic and microbial biomass C contents tended to increase with increasing the application rates of organic fertilizer, especially of compost, whereas increasing the rate of mineral fertilizer tended to suppress microbial biomass. Biochar was found to increase both organic and inorganic C contents in soil and not to interact with the effects of type and rate of fertilizer on C fractions. As a whole, our results suggest that the use of biochar as enhancer of semi-arid soils, either alone or combined with mineral and organic fertilizers, is unlikely to increase abiotic and biotic soil CO2 emissions.

  4. Ecological condition of central Australian arid-zone rivers.

    Science.gov (United States)

    Choy, S C; Thomson, C B; Marshall, J C

    2002-01-01

    Australian arid-zone rivers are known to be ecologically variable and go through "boom and bust" cycles based on highly variable and unpredictable flow regimes. They are facing increasing pressure from land and water resources development and, whilst they are considered to be still in relatively good condition, no studies have yet been carried out to verify this. Such baseline studies are crucial if we are to assess any ecological changes in response to development and management interventions. The ecological condition of four of these endorheic rivers (Georgina, Diamantina, Cooper-Thomson and Bulloo) flowing into the Lake Eyre and Bulloo Basins in central Australia was assessed using several criteria (level of human influence, habitat condition, water chemistry and aquatic macroinvertebrate composition). Using criteria based on the level of human influence, most of the sites were assessed to be relatively unimpacted (reference) condition. The most discernible and widespread impact was riparian and bank damage by stock access. However, the level of this impact was considered to be only moderate. Most aquatic macroinvertebrates found in the area are considered to be opportunistic and tolerant of a wide range of environmental conditions, but with their life histories known to be linked to flow conditions. Their trophic guild was dominated by collectors and predators. The AusRivAS modelled observed to expected values of macroinvertebrate composition indicated that there were differences in ecological condition between sites (e.g. different waterholes) and between times (e.g. seasons and years). Overall, 75% of sites were assessed to be good condition with the remainder being mildly impaired. Water chemistry of the sites was characterised by high spatial and temporal variability with low conductivity and alkaline pH, relatively high turbidity, total nitrogen and total phosphorus, and wide-ranging dissolved oxygen. Given the high variability in water quality and

  5. Application of Public-Private Partnership in Land Degradation Control and A Case Study

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The paper reviewed the background of public-private partnership (PPP) development, described PPP concept, characteristics and basic models, and analyzed the necessity and feasibility to develop land degradation control PPP. Then the experiences that Elion Resources Group in Inner Mongolia has accumulated in Kubuqi Desert control and development as well as the revelations were summarized with the hope to provide reference for establishing land degradation control PPP in arid area of western region.

  6. Land use in the northern Coachella Valley

    Science.gov (United States)

    Bale, J. B.; Bowden, L. W.

    1973-01-01

    Satellite imagery has proved to have great utility for monitoring land use change and as a data source for regional planning. In California, open space desert resources are under severe pressure to serve as a source for recreational gratification to individuals living in the heavily populated southern coastal plain. Concern for these sensitive arid environments has been expressed by both federal and state agencies. The northern half of the Coachella Valley has historically served as a focal point for weekend recreational activity and second homes. Since demand in this area has remained high, land use change from rural to urban residential has been occurring continuously since 1968. This area of rapid change is an ideal site to illustrate the utility of satellite imagery as a data source for planning information, and has served as the areal focus of this investigation.

  7. Living Lands

    DEFF Research Database (Denmark)

    Christensen, Suna Møller

    2014-01-01

    , hunters attended to questions like safe-journeying on ice or the role of natural surroundings in children’s education, in ways revealing a relational perception of ‘nature’ and dissolving culture-nature dualisms. Hunters’ experiences in living the land afforded children a dwelling position from which to...... grow with the features of the land. Framed this way, ‘nature’ was regarded as part of the social world. I suggest that learning among Arctic hunters is social and twofold. First, we can learn how human-environment relations influence individual life trajectories. Secondly, ‘nature’ as part of the...... social world pushes questions about education and life, disregarding being educated as human control of nature....

  8. 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.

  9. 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

  10. The experience of land cover change detection by satellite data

    Institute of Scientific and Technical Information of China (English)

    Lev SPIVAK; Irina VITKOVSKAYA; Madina BATYRBAYEVA; Alexey TEREKHOV

    2012-01-01

    Sigificant dependence from climate and anthropogenic influences characterize ecological systems of Kazakhstan.As result of the geographical location of the republic and ecological situation vegetative degradation sites exist throughout the territory of Kazakhstan.The major process of desertification takes place in the arid and semi-arid areas.To allocate spots of stable degradation of vegetation,the transition zone was first identified.Productivity of vegetation in transfer zone is slightly dependent on climate conditions.Multi-year digital maps of vegetation index were generated with NOAA satellite images.According to the result,the territory of the republic was zoned by means of vegetation productivity criterion.All the arable lands in Kazakhstan are in the risky agriculture zone.Estimation of the productivity of agricultural lands is highly important in the context of risky agriculture,where natural factors,such as wind and water erosion,can significantly change land quality in a relatively short time period.We used an integrated vegetation index to indicate land degradation measures to assess the inter-annual features in the response of vegetation to variations in climate conditions from lowresolution satellite data for all of Kazakhstan.This analysis allowed a better understanding of the spatial and temporal variations of land degradation in the country.

  11. 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

  12. 极端干旱荒漠的“荒漠化”%Desertification of extra-arid deserts

    Institute of Scientific and Technical Information of China (English)

    慈龙骏

    2011-01-01

    The desertification of extra-arid deserts discussed in this paper refers to land degradation caused by global changes including various human activities. Extra-arid deserts comprise 36.9% of the total area of arid lands in China. Fifty percent of extra-arid deserts have some productivity, and they can most often be characterized as the terminal point of the biogeochemical cycle system in the desert basin. These areas are important because of their enormous potential for scientific research and creative discoveries, as well as new frontiers for development of the national economy. These areas are also of great importance in the fields of energy, mineral resources, water resources, biodiversity, tourism, local specialized agriculture and other aspects. With the current global crisis of decreasing fertile lands and increasing population, these large areas of marginal land with potential productivity need to be better understood and reevaluated. The natural environments in the region of extra-arid deserts are extremely low because of destructive sand-storms, land degradation, global changes and greater human interference. Additionally, there has been a series of major ecological andenvironmental events that have seriously affected extra-arid deserts. Continued desertification in the extra-arid deserts has a strong adverse effect on the national economy and society. Because of the current national economic boom and biogeographical and biogeochemical evidence, now is the right time to develop a concept for extra-arid deserts, as well as their management and conservation. A proposed classification and characteristics of the desertification of these deserts and technical measures for their conservation and restoration are presented here. The futures of extra-arid deserts will depend on acceptance of this concept by both academia and the government. Incorporating I) the combating of desertification of extra-arid deserts, and ii) the ecological restoration of the Northwest

  13. Actinobacteria from arid and desert habitats: diversity and biological activity

    Directory of Open Access Journals (Sweden)

    Joachim eWink

    2016-01-01

    Full Text Available Abstract The lack of new antibiotics in the pharmaceutical pipeline guides more and more researchers to leave the classical isolation procedures and to look in special niches and ecosystems. Bioprospecting of extremophilic Actinobacteria through mining untapped strains and avoiding resiolation of known biomolecules is among the most promising strategies for this purpose. With this approach, members of acidtolerant, alkalitolerant, psychrotolerant, thermotolerant, halotolerant and xerotolerant Actinobacteria have been obtained from respective habitats. Among these, little survey exists on the diversity of Actinobacteria in arid areas, which are often adapted to relatively high temperatures, salt concentrations, and radiation. Therefore, arid and desert habitats are special ecosystems which can be recruited for the isolation of uncommon Actinobacteria with new metabolic capability.At the time of this writing, members of Streptomyces, Micromonospora, Saccharothrix, Streptosporangium, Cellulomonas, Amycolatopsis, Geodermatophilus, Lechevalieria, Nocardia and Actinomadura are reported from arid habitats. However, metagenomic data present dominant members of the communities in desiccating condition of areas with limited water availability that are not yet isolated. Furthermore, significant diverse types of polyketide synthase (PKS and nonribosomal peptide synthetase (NRPS genes are detected in xerophilic and xerotolerant Actinobacteria and some bioactive compounds are reported from them. Rather than pharmaceutically active metabolites, molecules with protection activity against drying such as Ectoin and Hydroxyectoin with potential application in industry and agriculture have also been identified from xerophilic Actinobacteria. In addition, numerous biologically active small molecules are expected to be discovered from arid adapted Actinobacteria in the future. In the current survey, the diversity and biotechnological potential of Actinobacteria

  14. Workshop on environmental changes of arid regions convenes in Inner Mongolia

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Hosted by the CAS Institute of Geology and Geophysics and the local government, the International Workshop on Environmental Changes and Sustainable Development in Arid and Semi-arid Regions was held recently in Alashan Left Banner, Inner Mongolia.

  15. Potential of arid zone vegetation as a source of substrates

    Energy Technology Data Exchange (ETDEWEB)

    Bassham, J.A.

    1977-11-01

    Three aspects of the potential of vegetation in arid zones as a source of substrates are discussed. The first includes the limitations on efficiency of conversion of solar energy to the stored chemical energy of biomass in green plants, and the subsequent biochemical pathways of carbon dioxide fixation and biosynthesis. Second is the potential of plants endogenous to arid zones. Finally, the use of covered agriculture or controlled environmental agriculture (CEA) is considered both in its present form and in terms of possible extenion to the large scale production of stable crops. (JGB)

  16. Restoration of surface-mined lands with rainfall harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Sauer, R.H.; Rickard, W.H.

    1982-12-01

    Strip mining for coal in the arid western US will remove grazing land as energy demands are met. Conventional resotration usually includes leveling the spoil banks and covering them with top soil, fertilizing, seeding and irrigation with well or river water. An overview of research on an alternate method of restoring this land is reported. From 1976 through 1981 studies were conducted on the use of water harvesting, the collection and use of rainfall runoff, to restore the vegetative productivity of strip mined lands in arid regions. These studies tested the technical and economic feasibility of using partially leveled spoil banks at strip mines as catchment areas to collect and direct runoff to the topsoiled valley floor where crops were cultivated. Information was collected on the efficiency of seven treatments to increase runoff from the catchment areas and on the productivity of seven crops. The experiments were conducted in arid areas of Washington, Arizona, and Colorado. It was concluded that water harvesting can replace or augment expensive and inadequate supplies of well and river water in arid regions with a suitable climate. These studies showed that some treatments provided adequate runoff to produce a useful crop in the valleys, thus making this alternative approach to restoration technically feasible. This approach was also potentially economically feasible where the treatment costs of the catchment areas were low, the treatment was effective, the crop was productive and valuable, and earthmoving costs were lower than with conventional restoration involving complete leveling of spoil banks. It was also concluded that water harvesting can be made more effective with further information on catchment area treatments, which crops are most adaptable to water harvesting, the optimum incline of the catchment areas and climatic influences on water harvesting.

  17. Global synthesis of groundwater recharge in semiarid and arid regions

    Science.gov (United States)

    Scanlon, Bridget R.; Keese, Kelley E.; Flint, Alan L.; Flint, Lorraine E.; Gaye, Cheikh B.; Edmunds, W. Michael; Simmers, Ian

    2006-10-01

    Global synthesis of the findings from 140 recharge study areas in semiarid and arid regions provides important information on recharge rates, controls, and processes, which are critical for sustainable water development. Water resource evaluation, dryland salinity assessment (Australia), and radioactive waste disposal (US) are among the primary goals of many of these recharge studies. The chloride mass balance (CMB) technique is widely used to estimate recharge. Average recharge rates estimated over large areas (40-374 000 km2) range from 0.2 to 35 mm year-1, representing 0.1-5% of long-term average annual precipitation. Extreme local variability in recharge, with rates up to 720 m year-1, results from focussed recharge beneath ephemeral streams and lakes and preferential flow mostly in fractured systems. System response to climate variability and land use/land cover (LU/LC) changes is archived in unsaturated zone tracer profiles and in groundwater level fluctuations. Inter-annual climate variability related to El Niño Southern Oscillation (ENSO) results in up to three times higher recharge in regions within the SW US during periods of frequent El Niños (1977-1998) relative to periods dominated by La Niñas (1941-1957). Enhanced recharge related to ENSO is also documented in Argentina. Climate variability at decadal to century scales recorded in chloride profiles in Africa results in recharge rates of 30 mm year-1 during the Sahel drought (1970-1986) to 150 mm year-1 during non-drought periods. Variations in climate at millennial scales in the SW US changed systems from recharge during the Pleistocene glacial period (10 000 years ago) to discharge during the Holocene semiarid period. LU/LC changes such as deforestation in Australia increased recharge up to about 2 orders of magnitude. Changes from natural grassland and shrublands to dryland (rain-fed) agriculture altered systems from discharge (evapotranspiration, ET) to recharge in the SW US. The impact of LU

  18. Evaluation of an extreme-condition-inverse calibration remote sensing model for mapping energy balance fluxes in arid riparian areas

    Science.gov (United States)

    Hong, S.-H.; Hendrickx, J. M. H.; Kleissl, J.; Allen, R. G.; Bastiaanssen, W. G. M.; Scott, R. L.; Steinwand, A. L.

    2014-12-01

    Accurate information on the distribution of the surface energy balance components in arid riparian areas is needed for sustainable management of water resources as well as for a better understanding of water and heat exchange processes between the land surface and the atmosphere. Since the spatial and temporal distributions of these fluxes over large areas are difficult to determine from ground measurements alone, their prediction from remote sensing data is very attractive as it enables large area coverage and a high repetition rate. In this study the Surface Energy Balance Algorithm for Land (SEBAL) was used to estimate all the energy balance components in the arid riparian areas of the Middle Rio Grande Basin (New Mexico), San Pedro Basin (Arizona), and Owens Valley (California). We compare instantaneous and daily SEBAL fluxes derived from Landsat TM images to surface-based measurements with eddy covariance flux towers. This study presents evidence that SEBAL yields reliable estimates for actual evapotranspiration rates in riparian areas of the southwestern United States. The great strength of the SEBAL method is its internal calibration procedure that eliminates most of the bias in latent heat flux at the expense of increased bias in sensible heat flux.

  19. Evaluation of an extreme-condition-inverse calibration remote sensing model for mapping energy balance fluxes in arid riparian areas

    Directory of Open Access Journals (Sweden)

    S.-H. Hong

    2014-12-01

    Full Text Available Accurate information on the distribution of the surface energy balance components in arid riparian areas is needed for sustainable management of water resources as well as for a better understanding of water and heat exchange processes between the land surface and the atmosphere. Since the spatial and temporal distributions of these fluxes over large areas are difficult to determine from ground measurements alone, their prediction from remote sensing data is very attractive as it enables large area coverage and a high repetition rate. In this study the Surface Energy Balance Algorithm for Land (SEBAL was used to estimate all the energy balance components in the arid riparian areas of the Middle Rio Grande Basin (New Mexico, San Pedro Basin (Arizona, and Owens Valley (California. We compare instantaneous and daily SEBAL fluxes derived from Landsat TM images to surface-based measurements with eddy covariance flux towers. This study presents evidence that SEBAL yields reliable estimates for actual evapotranspiration rates in riparian areas of the southwestern United States. The great strength of the SEBAL method is its internal calibration procedure that eliminates most of the bias in latent heat flux at the expense of increased bias in sensible heat flux.

  20. Disconnected runoff contributing areas: Evidence provided by ancient watershed management systems in arid north-eastern Marmarica (NW-Egypt)

    Science.gov (United States)

    Vetter, T.; Rieger, A.-K.; Nicolay, A.

    2014-05-01

    This study presents the importance of disconnectivity in dryland area runoff demonstrated by manmade water harvesting structures dated to Greco-Roman times. Located on the coastal strip of some 20 km width along the Mediterranean coast of modern northwestern Egypt covering the north-eastern part of the region known in antiquity as Marmarica, the area receives winterly rainfalls of up to 140 mm. Further south, precipitation decreases quickly and desert conditions become more pronounced. Bedrocks are predominantly calcareous, soils are loamy, stony, calcareous, and shallow, except in relief sinks with sedimentary deposits. The land rises from the coast up to 230 m a.s.l. on the Marmarica Plateau in a sequence of zonal northsloping plains and scarps the northern parts of which are dissected and drained by wadis. Agriculturally suitable areas comprise some 9% of the coastal zone and adjacent tablelands. Overland flow controls the discharge dynamics and is the main source of wadi runoff and hence agricultural water supply. The land use pattern is scattered because cropping areas depend mainly on suitability of soils and the generation of runoff harvest, which are closely interrelated because of the arid water and sediment regime. The patchiness of runoff generation increases further south where aridity is higher and topography inhibits greater drainage patterns. The abundance of cisterns, many of them originally Greco-Roman, is strong evidence that tableland overland flows occur and are frequently disconnected from larger drainage systems.

  1. Restoring the biological crust cover of soils across biomes in arid North America

    Science.gov (United States)

    Garcia-Pichel, Ferran; Antoninka, Anita; Bowker, Matthew; Giraldo Silva, Ana; Nelson, Corey; Velasco Ayuso, Sergio; Barger, Nichole; Belnap, Jayne; Reed, Sasha; Duniway, Michael

    2015-04-01

    Biological soil crust communities provide important ecosystem services to arid lands, particularly regarding soil fertility and stability against erosion. In North America, and in many other areas of the globe, increasingly intense human activities, ranging from cattle grazing to military training, have resulted in the significant deterioration of biological soil surface cover of soils. With the intent of attaining sustainable land use practices, we are conducting a 5-year, multi-institutional research effort to develop feasible soil crusts restoration strategies for US military lands. We are including field sites of varying climatic regions (warm and cold deserts, in the Chihuahuan Desert and in the Great Basin, respectively) and varying edaphic characteristics (sandy and silty soils in each). We have multiple aims. First, we aim to establishing effective "biocrust nurseries" that produce viable and pedigreed inoculum, as a supply center for biocrust restoration and for research and development. Second, we aim to develop optimal field application methods of biocrust inoculum in a series of field trials. Currently in our second year of research, we will be reporting on significant advances made on optimizing methodologies for the large-scale supply of inoculum based on a) pedigreed laboratory cultures that match the microbial community structure of the original sites, and b) "in soil" biomass enhancement, whereby small amounts of local crusts are nursed under greenhouse conditions to yield hundred-fold increases in biomass without altering significantly community structure. We will also report on field trials for methodologies in field application, which included shading, watering, application of chemical polymers, and soil surface roughening. In a soon-to-be-initiated effort we also aim to evaluate soil and plant responses to biocrust restoration with respect to plant community structure, soil fertility, and soil stability, in multi-factorial field experiments. An

  2. Impact and consequences of evapotranspiration changes on water resources availability in the arid Zhangye Basin, China

    NARCIS (Netherlands)

    Jin, X.; Schaepman, M.E.; Clevers, J.G.P.W.; Su, Z.

    2009-01-01

    Evapotranspiration (ET) plays an important role in the hydrological cycle and it is essential to estimate ET accurately for the evaluation of available water resources. This is most important in arid and semi-arid regions. In this paper, the long-term changes in daily ET in the semi-arid Zhangye Bas

  3. Developing a Land Suitability Index for Agricultural uses in Dry Lands from Geologic Point of View Using GIS - a Case Study from Jordan

    OpenAIRE

    Mohammmad Al Farajat; Alsharifa Hind Mohammad; Abdullah Diabat; Hassan Al Ibraheem

    2015-01-01

    DOI:10.17014/ijog.2.2.63-76In the context of the study, a Multi-criteria evaluation (MCE) in GIS was used in developing suitability index to optimize suitable lands for agricultural uses and seasonal farming in dry lands from geologic point of view. This study was performed in the areas between Mafraq and Zarqa Cities in Jordan which are classified as arid lands. The study aims at protecting groundwater from pollution, reducing soil salting, reducing irrigation water loss caused by evaporatio...

  4. Local facilitation, bistability and transitions in arid ecosystems

    NARCIS (Netherlands)

    Kefi, S.; Rietkerk, M.; Baalen, van M.; Loreau, M.

    2007-01-01

    Arid ecosystems are liable to undergo sudden discontinuous transitions from a vegetated to a desert state as a result of human pressure and climate change. A predictive framework about the conditions under which such transitions occur is lacking. Here, we derive and analyze a general model describin

  5. Extreme climatic events shape arid and semiarid ecosystems

    NARCIS (Netherlands)

    Holmgren, M.; Stapp, P.; Dickman, C.; Gracia, C.; Graham, S.

    2006-01-01

    Climatic changes associated with the El Nino Southern Oscillation (ENSO) can have a dramatic impact on terrestrial ecosystems worldwide, but especially on arid and semiarid systems, where productivity is strongly limited by precipitation. Nearly two decades of research, including both short-term exp

  6. Evaporation as the transport mechanism of metals in arid regions.

    Science.gov (United States)

    Lima, Ana T; Safar, Zeinab; Loch, J P Gustav

    2014-09-01

    Soils of arid regions are exposed to drought and drastic temperature oscillations throughout the year. Transport mechanisms in these soils are therefore very different from the ones in temperate regions, where rain dictates the fate of most elements in soils. Due to the low rainfall and high evaporation rates in arid regions, groundwater quality is not threatened and all soil contamination issues tend to be overlooked. But if soil contamination happens, where do contaminants go? This study tests the hypothesis of upward metal movement in soils when evaporation is the main transport mechanism. Laboratory evaporation tests were carried out with heavy metal spiked Saudi soil, using circulation of air as the driving force (Fig. 1). Main results show that loamy soil retains heavy metals quite well while evaporation drives heavy metals to the surface of a sandy soil. Evaporation transports heavy metals upward in sandy soils of arid regions, making them accumulate at the soil surface. Sand being the dominating type of soil in arid regions, soils can then be a potential source of contaminated aerosols and atmospheric pollution - a transboundary problem. Some other repercussions for this problem are foreseen, such as the public ingestion or inhalation of dust.

  7. Evaporation as the transport mechanism of metals in arid regions

    NARCIS (Netherlands)

    Lima, A.T.; Safar, Z.; Loch, J.P.G.

    2014-01-01

    Soils of arid regions are exposed to drought and drastic temperature oscillations throughout the year. Transport mechanisms in these soils are therefore very different from the ones in temperate regions, where rain dictates the fate of most elements in soils. Due to the low rainfall and high evapora

  8. Trends and responses to global change of China's arid regions

    Institute of Scientific and Technical Information of China (English)

    Weixi YANG

    2009-01-01

    Ⅰ analyzed and elaborated the trends in and responses to global change in arid regions of China, from the perspective of nine variables, i.e., temperature, precipitation, river runoff, melting glaciers, water level of lakes, wind power and evaporation, vegetation, oases, and desertification. The climate and hydrology data Ⅰ citedrepresent many years of observations. Ⅰ conclude that, since the 1980s, the climate in arid regions of China has clearly changed with rising temperatures and precipitation in most areas. Wind power and the number of galestorm days have continuously decreased, which resulted in an improvement of humid conditions and increases in river discharge and water levels of lakes. Simultaneously, vegetation also has improved and the process of deserti-fication has essentially been arrested. Although there are some unfavorable developments, such as decreased river flows or flow interruptions and downstream oases have suffered from degradation, these incidental cases should not distract our attention from the generally favorable trends during the middle and late 20th century. These discordant phenomena are not consequences of climate change but rather of unsuitable human activities. Despitea substantial increase in precipitation, the level of the original precipitation was so small that any increase in precipitation was still small. As a result, none of the fundamental conditions such as a scarcity of water resources and precipitation nor the landscape of drought-ridden deserts in the arid regions will change. The vulnerability of the eco-environmental system in the arid regions will not change fundamentally either in the near future.

  9. Evaporation as the transport mechanism of metals in arid regions

    KAUST Repository

    Lima, Ana T.

    2014-09-01

    Soils of arid regions are exposed to drought and drastic temperature oscillations throughout the year. Transport mechanisms in these soils are therefore very different from the ones in temperate regions, where rain dictates the fate of most elements in soils. Due to the low rainfall and high evaporation rates in arid regions, groundwater quality is not threatened and all soil contamination issues tend to be overlooked. But if soil contamination happens, where do contaminants go? This study tests the hypothesis of upward metal movement in soils when evaporation is the main transport mechanism. Laboratory evaporation tests were carried out with heavy metal spiked Saudi soil, using circulation of air as the driving force (Fig. 1). Main results show that loamy soil retains heavy metals quite well while evaporation drives heavy metals to the surface of a sandy soil. Evaporation transports heavy metals upward in sandy soils of arid regions, making them accumulate at the soil surface. Sand being the dominating type of soil in arid regions, soils can then be a potential source of contaminated aerosols and atmospheric pollution - a transboundary problem. Some other repercussions for this problem are foreseen, such as the public ingestion or inhalation of dust. © 2014 Elsevier Ltd.

  10. Evidence of Arid to Semi-arid Climate Near Western Pacific Warm Pool During Sea-Level Lowstands: Caliche Surfaces in Late Cenozoic Carbonates of Nansha Islands, South China Sea

    Science.gov (United States)

    Gong, S.; Mii, H.; Horng, C.; Huang, F.; Chi, W.; Yui, T.; Torng, P.; Huang, S.; Wang, S.; Wu, J.; Yang, K.

    2003-12-01

    Whether the climate of tropical seas during glacial periods became cold and dry has been an open debate. Models by different authors proposed the tropical sea-surface temperature (SST) during the Last Glacial Maximum (LGM) to be about 2\\deg lower, or 5-6\\deg lower than present. The controversy partly arise from disparate reconstructions of temperature from stable oxygen isotope archives of marine sediments. In this paper, we provide field evidence of semi-arid or arid climate during late Cenozoic sea-level lowstands from an atoll located in central South China Sea near the Western Pacific Warm Pool (WPWP). Lower rainfall and higher evaporation associated with the dry conditions might have resulted in less meteoric water component in the surface sea-water, and this factor should be taken into considerations in deciphering temperature from isotopic records. Taiping Islet (Itu Aba), located at N10\\deg 23' and E114\\deg 22' is part of the Nansha (Spratly) Islands near the northwestern margin of the Western Pacific Warm Pool. Rock cores of a borehole at Taiping became accessible to the authors in the recent years. We identified at least four subaerial exposure surfaces (SES) in the late Cenozoic carbonates. Caliche deposits are recognized on each of the four surfaces on the basis of alveolar texture, micro-rhizolith, caliche glaebules and corroded limestone nodules in reddish matrix (terra-rossa). Caliche developed on limestones typically forms in semi-arid to arid areas with annual precipitation from about 500 to 1000mm, while the modern annual rainfall of Nansha Island is 1800-2100mm. The occurrence of the Nansha caliche suggests the climate was much drier than present during the sea-level lowstands represented by the four SES. During the sea-level falls, reduced surface area of South China Sea with continental shelves exposed might have resulted in less moistures in the atmosphere and therefore less precipitation and higher evaporation rates. As a result, the

  11. Diffusion of agricultural innovation: farmers opinion on land conservation measures in pishin, pakistan

    International Nuclear Information System (INIS)

    Land resources in Pakistan are under severe threat of degradation due to population growth. The situation is more serious in the arid and semi-arid areas, where the natural resources, especially the water-resources, are scarce. This paper reviews the study conducted to investigate the farmers views on land conservation measures in Pishin, Pakistan. Data were collected through survey questionnaires, focus-group discussions and field observations. Increased expenditure, poor extension services and lack of awareness were found to be the major reasons behind the non-adoption of the needed conservation measures. Significant differences were found for adoption of conservation measures by household categories. The study proposes government support and proper assistance to farmers by extension agents for sustainable use of land and water resources. (author)

  12. Ground-Water Recharge in the Arid and Semiarid Southwestern United States

    Science.gov (United States)

    Stonestrom, David A.; Constantz, Jim; Ferre, Ty P.A.; Leake, Stanley A.

    2007-01-01

    Ground-water recharge in the arid and semiarid southwestern United States results from the complex interplay of climate, geology, and vegetation across widely ranging spatial and temporal scales. Present-day recharge tends to be narrowly focused in time and space. Widespread water-table declines accompanied agricultural development during the twentieth century, demonstrating that sustainable ground-water supplies are not guaranteed when part of the extracted resource represents paleorecharge. Climatic controls on ground-water recharge range from seasonal cycles of summer monsoonal and winter frontal storms to multimillennial cycles of glacial and interglacial periods. Precipitation patterns reflect global-scale interactions among the oceans, atmosphere, and continents. Large-scale climatic influences associated with El Ni?o and Pacific Decadal Oscillations strongly, but irregularly, control weather in the study area, so that year-to-year variations in precipitation and ground-water recharge are large and difficult to predict. Proxy data indicate geologically recent periods of naturally occurring multidecadal droughts unlike any in the modern instrumental record. Any anthropogenically induced climate change will likely reduce ground-water recharge through diminished snowpack at higher elevations. Future changes in El Ni?o and monsoonal patterns, both crucial to precipitation in the study area, are highly uncertain in current models. Current land-use modifications influence ground-water recharge through vegetation, irrigation, and impermeable area. High mountain ranges bounding the study area?the San Bernadino Mountains and Sierra Nevada to the west, and the Wasatch and southern Colorado Rocky Mountains to the east?provide external geologic controls on ground-water recharge. Internal geologic controls stem from tectonic processes that led to numerous, variably connected alluvial-filled basins, exposure of extensive Paleozoic aquifers in mountainous recharge areas

  13. Characterization of arid land water-balance processes at Yucca Mountain, Nevada

    Science.gov (United States)

    Flint, Alan L.; Flint, Lorraine E.; Hevesi, Joseph A.; Hudson, David B.

    Water-balance processes were characterized to estimate net infiltration at Yucca Mountain, Nevada, to help determine the suitability of this site as a potential high-level radioactive waste repository. Detailed water-content data were collected from 98 boreholes located in four topographic positions (ridgetops, sideslopes, albvial terraces, and active channels) representing four infiltration zones. These data include monthly volumetric water-content readings with depth for 1984 through 1995 and water potential measurements made at a soil-bedrock contact in 1995. These data, combined with measured evapotranspiration and precipitation data, piovide the seasonal and areal distribution of changes in volumetric water content needed to assess hydrologic processes contributing to net infiltration. The conceptual model of infiltration at Yucca Mountain describes the processes of precipitation, runoff, evapotranspiration, and vertical redistribution of water in the shallow unsaturated zone. Field observations and measurements and data analysis indicate that, in order for net infiltration to occur, water must reach and nearly saturate the soil-bedrock contact to initiate flow in the underlying fractured bedrock, and water must penetrate deep enough to escape the influences of evapotranspiration. The amount of net infiltration is a function of how long or how frequently the contact is saturated. Water must penetrate deep enough to escape the influences of evapotranspiration. The penetration of water through the soil is influenced primarily by the seasonal timing and areal distribution of precipitation, the storage capacity of soil, and the properties of the underlying bedrock.

  14. VEGETATIVE REHABILITATION OF ARID LAND DISTURBED IN THE DEVELOPMENT OF OIL SHALE AND COAL

    Science.gov (United States)

    Field experiments were established on sites disturbed by exploratory drilling in the oil shale region of northeastern Utah and on disturbed sites on a potential coal mine in south central Utah. Concurrently, greenhouse studies were carried out using soil samples from disturbed si...

  15. Survey on pigeon pea production systems, utilization and marketing in semi-arid lands of Kenya

    OpenAIRE

    Baudoin J.P.; Le Roi A.; Mergeai G.; Kimani P.; Mwang'ombe A.; Olubayo F; Smith C.; Audi P.

    2001-01-01

    In order to assess the status of pigeonpea (Cajanus cajan (L.) Millsp.) production in Kenya, two surveys were carried out in Makueni and Mbeere Districts in areas representative of the main agro-ecological pigeonpea producing zone of the country : (Mid-altitude ASAL). Participatory Rural Appraisal (PRA) approach was chosen as research method and was completed by household interviews based on a semi-structured questionnaire. The main points developed are the presentation of the different farmi...

  16. Ecological footprint analysis based on RS and GIS in arid land

    Institute of Scientific and Technical Information of China (English)

    CHANGBin; XIONGLiya

    2005-01-01

    Sustainable development has become a primary objective for many countries and regions throughout the world now. The ecological footprint (EF) is a kind of concise method of quantifiably measuring the natural capital consumption and it can reflect the goal of sustainability. In this paper, the concept, the theory and method of ecological footprint are introduced. On this basis, the study brings forward the method of ecological footprint and capacity prediction. The method is employed for the ecological footprint prediction combining consumption model with population model and the technique is adopted for the ecological capacity (EC) prediction uniting the Geographical Cellular Automata (Geo CA) and Geographic Information System (GIS). The above models and methods are employed to calculate EF and EC in 1995 and 2000 and predict them in 2005 in Hexi Corridor. The result shows that EF is continually increasing, and EC ascended in the anterior 5 years and will descend in the posterior 5 years. This suit of method is of the character of accuracy and speediness.

  17. Survey on pigeon pea production systems, utilization and marketing in semi-arid lands of Kenya

    Directory of Open Access Journals (Sweden)

    Baudoin J.P.

    2001-01-01

    Full Text Available In order to assess the status of pigeonpea (Cajanus cajan (L. Millsp. production in Kenya, two surveys were carried out in Makueni and Mbeere Districts in areas representative of the main agro-ecological pigeonpea producing zone of the country : (Mid-altitude ASAL. Participatory Rural Appraisal (PRA approach was chosen as research method and was completed by household interviews based on a semi-structured questionnaire. The main points developed are the presentation of the different farming systems in which pigeonpea is considered as an important legume crop, the identification of the factors explaining pigeonpea production variations, the quantification of the use of improved varieties and improved production practices, and the analysis of the major patterns and trends in pigeonpea production, consumption and marketing.

  18. Reforestation in Arid Lands. Appropriate Technologies for Development. Manual M-5.

    Science.gov (United States)

    Palmer, Virginia C., Ed.

    This manual presents some current, state-of-the-art examples of forestry programs in West Africa. It is based on the collective experiences of foresters and of local farmers and herders. Since many of the problems of reforestation of dry areas are the same worldwide, the text (which focuses on the broad subject of project implementation) includes…

  19. Land Use and Land Cover - Montana Land Cover Framework 2013

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This statewide land cover theme is a baseline digital map of Montana's natural and human land cover. The baseline map is adapted from the Northwest ReGAP project...

  20. 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

  1. Spatial pattern of nitrogen isotopes as an indicator of ecosystem responses to rainfall in semi-arid and arid grasslands

    Science.gov (United States)

    WANG, C.; Bai, E.; Liu, D.; Fang, T. Y.; Jiang, P.; Han, G. X.

    2013-12-01

    Nitrogen (N) is an essential element for plant growth, however, whether it is a limiting factor of plant growth in water-limited areas is still not clear. Here we examined spatial variations of plant and soil stable N isotopes along a 3200 km precipitation gradient and proposed a conceptual model to explain ecosystem responses to increasing precipitation in arid and semi-arid grasslands in China. Soil δ15N increased with increasing MAP in areas with MAP areas with 200 mm 200 mm. In areas with MAP nutrient cycling in arid and semi-arid areas. If future climate change leads to drier climate in dryland, the uncoupled plant and microbial response may cause more N losses and higher ecosystem vulnerability. 3 Soil organic carbon (Soil C, a), total nitrogen (Soil N, b), C/N (c) and δ15N (d) of study sites along a MAP gradient. Relationship between MAP and foliar δ15N (a) and root δ15N (b).

  2. 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.

  3. 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

  4. Experimental Study on Isotope Fractionation of Soil water in Arid Environments

    Science.gov (United States)

    Horita, J.; Lin, Y.

    2015-12-01

    Soil water dynamics within a thick vadose (unsaturated) zone is a key component in the hydrologic cycle in arid regions. The partitioning of precipitation and soil water into fluxes of percolation to the subsurface, surface runoff and evapotranspiration at the land-atmosphere-vegetation interface is accompanied by characteristic δ2H and δ18O values of water. The isotopic composition of the transpiration flux is very similar to soil water, since the uptake by plant roots is usually not associated with isotope fractionation. The isotopic composition of evaporation flux from unsaturated soils, which becomes an important flux in arid regions, has extensively been modeled by the Craig-Gordon model with the assumption that equilibrium isotopic fractionation between adsorbed/pored condensed water within soils and water vapor is identical to that between bulk liquid water and vapor. To test this critical assumption, we have conducted laboratory experiments on equilibrium isotope fractionation between adsorbed water in mesoporous silica (15nm pore, as soil analog) and the vapor. Firstly, the adsorption/desorption isotherms of H2O and N2 in the silica are determined at 30°C and liq-N2 temperature, respectively, and large hysteresis loops were observed. Secondly, the isotope fractionation factors between condensed water in the silica pores and the vapor (18αsilica water-vapor and 2αsilica water-vapor for oxygen and hydrogen isotopes, respectively) were determined at 30°C along the adsorption curve from near saturation pressure (p/po=1). We found that 18αsilica water-vapor values are smaller than that between free liquid-vapor (1.0088) and progressively decreased from1.0083 at p/po= 0.9 to 1.0054 at p/po=0.5, establishing a trend very similar to the isotherm curve. The corresponding 2αsilica water-vapor values are also smaller than that of free liquid-vapor system (1.0740) and decreased from 1.0651 at p/po=0.9 to 1.0295 at p/po=0.5. Our experimental results challenge

  5. Quantitative assessment and analysis on the dynamic change of ecological capital in arid areas

    Institute of Scientific and Technical Information of China (English)

    CHEN Xi; ZHANG Qing; ZHOU Kefa; SUN Li

    2006-01-01

    Ecological capital is the summation of the direct value of biological resources and the ecological service function value of ecosystems. Under the support of RS, GPS and GIS, in this paper the RS-based quantitative measurement model of assessing ecological capital is developed based on the traditional ecology theory and the research on the value of ecological capital per unit area by using the ecological parameters including Landsat TM data,CBERS satellite data, meteorological data, MODIS satellite data, land cover data and field-measured data. A case study on the spatiotemporal distribution of ecological capital in Changji Hui Autonomous Prefecture in 1990, 1995 and 2003 is carried out, and the dynamic change of ecological capital in the prefecture is measured and compared with GDP. The maps of the spatial distribution of ecological capital in the study area are charted, and the characteristics of spatial distribution of ecological capital are analyzed.The results show that the values of ecological capital in the prefecture in 1990, 1995 and 2003 were 1.47368×1011, 1.661 60×1011 and 1.77895×1011yuan RMB (hereafter referred to as yuan) respectively, and that in spatial distribution, the ecological capital decreases from the alpine zones to the plains and from the oases to the deserts, which accords with the zonal distribution of vegetation in arid areas.The measured results can more objectively reflect the ecological capital and its spatial distribution in arid areas, provide an ideal foundation for further study in the future, and can also be combined with the study on service functions of ecosystems and the regional planning as an important basis of regional planning.

  6. Digital Mapping of Soil Properties Using Multivariate Statistical Analysis and ASTER Data in an Arid Region

    Directory of Open Access Journals (Sweden)

    Said Nawar

    2015-01-01

    Full Text Available Modeling and mapping of soil properties has been identified as key for effective land degradation management and mitigation. The ability to model and map soil properties at sufficient accuracy for a large agriculture area is demonstrated using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER imagery. Soil samples were collected in the El-Tina Plain, Sinai, Egypt, concurrently with the acquisition of ASTER imagery, and measured for soil electrical conductivity (ECe, clay content and soil organic matter (OM. An ASTER image covering the study area was preprocessed, and two predictive models, multivariate adaptive regression splines (MARS and the partial least squares regression (PLSR, were constructed based on the ASTER spectra. For all three soil properties, the results of MARS models were better than those of the respective PLSR models, with cross-validation estimated R2 of 0.85 and 0.80 for ECe, 0.94 and 0.90 for clay content and 0.79 and 0.73 for OM. Independent validation of ECe, clay content and OM maps with 32 soil samples showed the better performance of the MARS models, with R2 = 0.81, 0.89 and 0.73, respectively, compared to R2 = 0.78, 0.87 and 0.71 for the PLSR models. The results indicated that MARS is a more suitable and superior modeling technique than PLSR for the estimation and mapping of soil salinity (ECe, clay content and OM. The method developed in this paper was found to be reliable and accurate for digital soil mapping in arid and semi-arid environments.

  7. Understanding land administration systems

    OpenAIRE

    P. Williamson, Ian; Enemark, Stig; Wallace, Judy; Rajabifard, Abbas

    2008-01-01

    This paper introduces basic land administration theory and highlights four key concepts that are fundamental to understanding modern land administration systems - firstly the land management paradigm and its influence on the land administration framework, secondly the role that the cadastre plays in contributing to sustainable development, thirdly the changing nature of ownership and the role of land markets, and lastly a land management vision that promotes land administration in support of ...

  8. Drought, change and resilience in South Africa’s arid and semi-arid rangelands

    Directory of Open Access Journals (Sweden)

    Susanne Vetter

    2009-12-01

    Full Text Available Droughts can have serious ecological and economic consequences and will pose an increasing challenge to rangeland users as the global climate is changing. Finding ways to reduce ecological and economic impacts of drought should thus be a major research thrust. Resilience, defined as the amount of perturbation a social or ecological system can absorb without shifting to a qualitatively different state, has emerged as a prominent concept in ecosystem ecology and more recently as a conceptual framework for understanding and managing complex social-ecological systems. This paper discusses the application and relevance of resilience to understanding and managing ecosystem change, and enhancing the capacity of land users to adapt to droughts. Drought can trigger vegetation change and factors such as grazing management can influence the likelihood of such transitions. Drought can cause differential mortality of perennial plants and this could provide an opportunity for rangeland restoration by opening up establishment sites for desirable species. The capacity of land users to cope with drought is influenced by the resilience of their agro-ecosystems, the diversity of livelihood options, access to resources and institutional support. By these criteria, current agricultural development approaches in South Africa, particularly in communal rangelands and areas of land reform, are unlikely to enhance land users’ resilience to drought and other perturbations.

  9. 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

  10. Phosphorus transformations along a large-scale climosequence in arid and semiarid grasslands of northern China

    Science.gov (United States)

    Feng, Jiao; Turner, Benjamin L.; Lü, Xiaotao; Chen, Zhenhua; Wei, Kai; Tian, Jihui; Wang, Chao; Luo, Wentao; Chen, Lijun

    2016-09-01

    The Walker and Syers model of phosphorus (P) transformations during long-term soil development has been verified along many chronosequences but has rarely been examined along climosequences, particularly in arid regions. We hypothesized that decreasing aridity would have similar effects on soil P transformations as time by increasing the rate of pedogenesis. To assess this, we examined P fractions in arid and semiarid grassland soils (0-10 cm) along a 3700 km aridity gradient in northern China (aridity between 0.43 and 0.97, calculated as 1 - [mean annual precipitation/potential evapotranspiration]). Primary mineral P declined as aridity decreased, although it still accounted for about 30% of the total P in the wettest sites. In contrast, the proportions of organic and occluded P increased as aridity decreased. These changes in soil P composition occurred in parallel with marked shifts in soil nutrient stoichiometry, with organic carbon:organic P and nitrogen:organic P ratios increasing with decreasing aridity. These results indicate increasing abundance of P relative to carbon or nitrogen along the climosequence. Overall, our results indicate a broad shift from abiotic to biotic control on P cycling at an aridity value of approximately 0.7 (corresponding to about 250 mm mean annual rainfall). We conclude that the Walker and Syers model can be extended to climosequences in arid and semiarid ecosystems and that the apparent decoupling of nutrient cycles in arid soils is a consequence of their pedogenic immaturity.

  11. 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.

  12. Land use/ land cover and ecosystem functions change in the grassland restoration program areas in China from 2000 to 2010

    Science.gov (United States)

    Zhang, H.; Fan, J.

    2015-12-01

    The grassland restoration areas in China, most of which was located in arid and semi-arid areas, are affected by climate change and anthropogenic activities. Using the 3S (RS, GIS, GPS) technologies, quantitative analysis method of landscape patterns and ecological simulation, this study examines the spatiotemporal characteristics of land use/ land cover and ecosystem functions change in the grassland restoration areas in China from 2000 to 2010. We apply two parameters land use transfer matrix and land use dynamic degree to explore the speed and regional differentiation of land use change. We propose vegetation coverage, net primary production (NPP), soil and water conservation capacity to assess the ecosystem functions. This study analyzes the characteristics of landscape patterns at the class and landscape levels and explores the ecological effect of land use pattern and regional ecological processes. The results show that: (1) Grassland and others were the main landscape types in the study area in the past decade. The ecosystem structure was stable. About 0.37% of the total grassland area in 2000 experienced change in land use / land cover types. The area of woodlands, wetlands, farmlands, and built-up areas expanded. The area of others has declined. (2) The dynamic degree of regional land use was less than one percent in the recent ten years. The speed of land use and land cover change was low, and regional differentiation of change between the provinces was small. (3) The matrix of the landscape did not change in the study area. Landscape fragmentation index values decreased progressively; landscape diversity rose continuously; landscape aggregation and continuity decreased slightly; the landscape maintained relative integrity. (4) Ecosystem functions has increased as a whole. The vegetation coverages with significant increase (with a 1.99% yr-1 slope of regression) in the total study area; NPP has a fluctuating and increasing tendency, ranging from 218.23 g

  13. Integrated Land Management

    DEFF Research Database (Denmark)

    Enemark, Stig

    2004-01-01

    This paper aims to build a general understanding and conceptual approach to integrated land management. The conceptual understanding may take the form of a hierarchy of levels. The foundation stone is an overall national land policy. Appropriate cadastral systems support land policies by providing...... for integrated land management includes some educational and professional challenges to be met at the threshold of the third millennium.    In short, it is critical that we prepare the profession as well the educational system to meet the challenges of tomorrow in achieving sustainable urban and rural...... identification of the land parcels and a framework for security of tenure, land value and land use. Appropriate cadastral systems support a wider land administration infrastructure within the areas of land tenure, land value and land use. Appropriate land administration systems then form the basic for sound land...

  14. No Land Let Idle

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    China steps up efforts to combat land hoarding to alleviate housing price hikes China’s real estate developers are under pressure from land administrators taking a harder stance against idle land-land purchased for a specific project but left undeveloped for an extensive period of time. The Ministry of Land and Resources (MLR) said real estate develop-

  15. Land, kennis, moed en eenheid: conflicterende discoursen binnen samenleving en gezin over landbouw en droogte in Noordoost Brazilië

    NARCIS (Netherlands)

    Peerboom, I.B.F.C.

    2012-01-01

    This dissertation examines the survival strategies of family farmers in Conceição do Coité, Bahia, in semi-arid Brazil in 1997 and 2008 by using the livelihood framework. It analyses natural capital (land), human capital (work ethic and knowledge), and social capital (mutual aid). Greater access to

  16. Responses of vertical soil moisture to rainfall pulses and land uses in a typical loess hilly area, China

    OpenAIRE

    Yu, Y.; Wei, W.; Chen, L. D.; Yang, L; F. Y. Jia; H. D. Zhang

    2014-01-01

    Soil moisture plays a key role in vegetation restoration and ecosystem stability in arid and semiarid regions. The response of soil moisture to rainfall pulses is an important hydrological process, which is strongly influenced by land use during the implementation of vegetation restoration measures. In this study, vertical soil moisture variations of woodland (Pinus tabulaeformis), native grassland (Stipa bungeana), shrubland Hippophea rhamnoides), cropland (Trit...

  17. Soil water infiltration impacted by maize (zea mays) growth on sloping agricultural land of the loess plateau

    Science.gov (United States)

    Increasing infiltration rates of sloping agricultural land from arid and semiarid regions not only affects water supply and precipitation transformations in soil directly, but also impacts erosion intensity. This is extremely important to the Loess Plateau regions of Northwest China, where a majorit...

  18. Land use and coal technology

    International Nuclear Information System (INIS)

    The Arid Lands Ecology Reserve and the Hanford National Environmental Research Park were established to promote the use of the Hanford Site for ecological research, especially studies related to energy technologies and their potential for environmental impacts. Coal is currently regarded as the most dependable interim source of energy in the United States. To meet expected demands, coal needs to be mined in large quantities and may be mined predominantly in locations of sparse precipitation. Often the most economical way to extract coal is through surface mining. It is expected that following coal extraction the pits will be filled with overburden, graded to approximate original contour, native topsoil applied to prescribed depths and planted with climatically adapted herbs, shrubs or trees. Because primary productivity in dry regions is characteristically low, it is realistic to expect, if the above procedure is followed, that the revegetated surfaces will also produce little phytomass in the years following restoration. Appropriate data are needed for accurate estimation of the economic feasibility of a particular restoration practice or its alternative. Research programs are discussed briefly

  19. Land Cover - Minnesota Land Cover Classification System

    Data.gov (United States)

    Minnesota Department of Natural Resources — Land cover data set based on the Minnesota Land Cover Classification System (MLCCS) coding scheme. This data was produced using a combination of aerial photograph...

  20. No Land Let Idle

    Institute of Scientific and Technical Information of China (English)

    LAN XINZHEN

    2010-01-01

    @@ China's real estate developers are under pressure from land administrators taking a harder stance against idle land-land purchased for a specific project but left undeveloped for an extensive period of time.

  1. Land rush: simulating negotiations over land rights

    OpenAIRE

    Ansoms, An; Bogaerts, Okke; Claessens, Klara; Geenen, Sara

    2015-01-01

    LAND RUSH is a board game that allows participants to critically assess the ways in which different social classes face both opportunities and constraints in securing land rights and in managing the acquired land sustainably in an extremely competitive environment. The game illustrates three characteristics of contemporary land dynamics in an altering world. First, the logics of smallholder farmers are largely oriented towards risk diversification, and often contrast with those of current agr...

  2. Uranium isotopes in carbonate aquifers of arid region setting

    DEFF Research Database (Denmark)

    Alshamsi, Dalal M.; Murad, Ahmed A.; Aldahan, Ala;

    2013-01-01

    Groundwater in arid and semiarid regions is vital resource for many uses and therefore information about concentrations of uranium isotopes among other chemical parameters are necessary. In the study presented here, distribution of 238U and 235U in groundwater of four selected locations in the so......Groundwater in arid and semiarid regions is vital resource for many uses and therefore information about concentrations of uranium isotopes among other chemical parameters are necessary. In the study presented here, distribution of 238U and 235U in groundwater of four selected locations...... in the southern Arabian peninsula, namely at two locations within the United Arab Emirates (UAE) and two locations in Oman are discussed. The analyses of the uranium isotopes were performed using ICP-MS and the results indicated a range of concentrations for 235U and 238 U at 3–39 ng L-1 (average: 18 ng L-1...

  3. On coordinated development of oasis and environment in arid area

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based upon the formation and evolution of oasis and the factors restricting the coordinated development of oasis economy and environment, this paper presents a goal of the development in coordination. It suggests that the sustainable survival and development of oasis could be ensured only if the oasis-desert and water source ecology are managed in a combined way to form a macro system. In light with the above mentioned, the approach to the development of economy and environment of oasis in arid area should depend upon the establishment of an oasis ecological and economic system, which suits the arid environment and promotes the efficiency of resource configuration, stabilizes economic increment and benefits ecological development.

  4. Expanding the phenotypic spectrum of ARID1B-mediated disorders and identification of altered cell-cycle dynamics due to ARID1B haploinsufficiency

    DEFF Research Database (Denmark)

    Sim, J. C. H.; White, S. M.; Fitzpatrick, E.;

    2014-01-01

    patient-derived and ARID1B knockdown fibroblasts after serum starvation demonstrated delayed cell cycle re-entry associated with reduced cell number in the S-1 phase. Based on the patient's distinctive phenotype, we ascertained four additional patients and identified heterozygous de novo ARID1B frameshift...

  5. Analyzing Land Cover Change in Kazakhstan: Land Surface Phenology, Climatic Variation, and Sensor Artifacts

    Science.gov (United States)

    de Beurs, K. M.; Henebry, G. M.

    2003-12-01

    The collapse of the economic and political institutions of the Soviet Union in the early 1990s led to widespread agricultural de-intensification, land abandonment, loss of livestock, and decreased grazing pressure. In semi-arid to arid regions dominated by dryland agriculture and grazing, the quantification of land cover change must distinguish anthropogenic forcings from interannual climatic variation and the peculiarities associated with specific sensor systems. Were the land cover changes that occurred in Kazakhstan following independence in 1991 of sufficient magnitude to alter the land surface phenology at resolutions relevant to climate models? To explore this question it is necessary first to partition the sources of variation in the image archive. We used the standard Pathfinder AVHRR Land (PAL) dataset, which consists of global 10 d maximum NDVI composites from 7/1981 to 9/2001 at 8 km resolution. To what extent are the PAL data affected by sensor artifacts that may mask other kinds of change? We evaluated 19 subsets of 1600 sq km, one for each ecoregion of Kazakhstan as delineated by the World Wildlife Fund. To minimize residual cloud contamination in the PAL data, a modified version of the best index slope extraction algorithm was applied. The method filters distortions without altering the seasonal NDVI pattern. We pursued two complementary aspects of change analysis: (1) detection of trends within each sensor's tenure and (2) detection of trends and discontinuities across the entire observational period. Seasonal polynomial models of NDVI phenology were developed to relate accumulated growing degree-day with NDVI. To test for trends within periods, both the residuals and the filtered data were submitted to seasonal Mann-Kendall tests that were modified to correct for serial correlation. To identify discontinuities, the entire series was tested using the standard normal homogeneity test (SNHT) without trend. The Kruskal-Wallis test with Bonferroni

  6. 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

  7. Desert Pavement Process and Form: Modes and Scales of Landscape Stability and Instability in Arid Regions

    Science.gov (United States)

    Wells, Stephen G.; McFadden, Leslie D.; McDonald, Eric V.; Eppes, Martha C.; Young, Michael H.; Wood, Yvonne A.

    2014-05-01

    Desert pavements are recognized in arid landscapes around the world, developing via diminution of constructional/depositional landform relief and creating a 1-2 stone thick armor over a "stone free" layer. Surface exposure dating demonstrates that clasts forming the desert pavements are maintained at the land surface over hundreds of thousands of years, as aeolian fines are deposited on the land surface, transported into the underlying parent material and incorporated into accretionary soil horizons (e.g., the stone free or vesicular [Av] horizon). This surface armor provides long-term stability over extensive regions of the landscape. Over shorter time periods and at the landform-element scale, dynamic surficial processes (i.e., weathering, runoff) continue to modify the pavement form. Clast size reduction in comparison to underlying parent material, along with armoring and packing of clasts in pavements contribute to their persistence, and studies of crack orientations in pavement clasts indicate physical weathering and diminution of particle size are driven by diurnal solar insolation. Over geologic time, cracks form and propagate from tensile stresses related to temporal and spatial gradients in temperature that evolve and rotate in alignment with the sun's rays. Observed multimodal nature of crack orientations appear related to seasonally varying, latitude-dependent temperature fields resulting from solar angle and weather conditions. Surface properties and their underlying soil profiles vary across pavement surfaces, forming a landscape mosaic and controlling surface hydrology, ecosystem function and the ultimate life-cycle of arid landscapes. In areas of well-developed pavements, surface infiltration and soluble salt concentrations indicate that saturated hydraulic conductivity of Av horizons decline on progressively older alluvial fan surfaces. Field observations and measurements from well-developed desert pavement surfaces landforms also yield

  8. Evolutionary shifts in habitat aridity predict evaporative water loss across squamate reptiles.

    Science.gov (United States)

    Cox, Christian L; Cox, Robert M

    2015-09-01

    Aridity is an important determinant of species distributions, shaping both ecological and evolutionary diversity. Lizards and snakes are often abundant in deserts, suggesting a high potential for adaptation or acclimation to arid habitats. However, phylogenetic evidence indicates that squamate diversity in deserts may be more strongly tied to speciation within arid habitats than to convergent evolution following repeated colonization from mesic habitats. To assess the frequency of evolutionary transitions in habitat aridity while simultaneously testing for associated changes in water-balance physiology, we analyzed estimates of total evaporative water loss (EWL) for 120 squamate species inhabiting arid, semiarid, or mesic habitats. Phylogenetic reconstructions revealed that evolutionary transitions to and from semiarid habitats were much more common than those between arid and mesic extremes. Species from mesic habitats exhibited significantly higher EWL than those from arid habitats, while species from semiarid habitats had intermediate EWL. Phylogenetic comparative methods confirmed this association between habitat aridity and EWL despite phylogenetic signal in each. Thus, the historical colonization of arid habitats by squamates is repeatedly associated with adaptive changes in EWL. This physiological convergence, which may reflect both phenotypic plasticity and genetic adaptation, has likely contributed to the success of squamates in arid environments.

  9. Wind power variations under humid and arid meteorological conditions

    International Nuclear Information System (INIS)

    Highlights: • It indicates the role of weather parameters’ roles in the wind energy calculation. • Meteorological variables are more significant in arid regions for wind power. • It provides opportunity to take into consideration air density variability. • Wind power is presented in terms of the wind speed, temperature and pressure. - Abstract: The classical wind power per rotor area per time is given as the half product of the air density by third power of the wind velocity. This approach adopts the standard air density as constant (1.23 g/cm3), which ignores the density dependence on air temperature and pressure. Weather conditions are not taken into consideration except the variations in wind velocity. In general, increase in pressure and decrease in temperature cause increase in the wind power generation. The rate of increase in the pressure has less effect on the wind power as compared with the temperature rate. This paper provides the wind power formulation based on three meteorological variables as the wind velocity, air temperature and air pressure. Furthermore, from the meteorology point of view any change in the wind power is expressed as a function of partial changes in these meteorological variables. Additionally, weather conditions in humid and arid regions differ from each other, and it is interesting to see possible differences between the two regions. The application of the methodology is presented for two meteorology stations in Istanbul, Turkey, as representative of the humid regions and Al-Madinah Al-Monawwarah, Kingdom of Saudi Arabia, for arid region, both on daily record bases for 2010. It is found that consideration of air temperature and pressure in the average wind power calculation gives about 1.3% decrease in Istanbul, whereas it is about 13.7% in Al-Madinah Al-Monawwarah. Hence, consideration of meteorological variables in wind power calculations becomes more significant in arid regions

  10. 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...

  11. A Feasibility Study of Geologic Water Storage in Arid Regions

    Science.gov (United States)

    Fairley, J. P.; Preuit, T.

    2001-05-01

    An important control on the carrying capacity of arid and semi-arid regions is the ability to develop and maintain a reliable water supply for domestic and agricultural use. In the semi-arid highlands of southern Peru, the pre-Columbian Incas developed a technique of collecting and storing basin yields by controlling the discharge boundary of an existing aquifer. This water resource management strategy has been dubbed "Geologic Water Storage" (Fairley, in review). Yield from at least one such system near Cuzco, Peru, has provided a reliable source of irrigation water for rural farmers to the present day. The geologic water storage systems of southern Peru suggested the possibility of developing a similar system to water stock in rural Idaho. Annual precipitation in Idaho is about one-third that of southern Peru, and obtaining an adequate stock water supply is often problematic. The application of a simple lumped capacitance model to a selected basin in central Idaho showed that it may be physically and economically feasible to modify the basin characteristics to prolong water availability at the site. A more detailed study of this problem, that includes field characterization of the site, is necessary to substantiate the model results. If further studies and field trials confirm the viability of geologic water storage, this approach may find applications in many rural and developing areas, both nationally and internationally.

  12. Saline dust storms and their ecological impacts in arid regions

    Institute of Scientific and Technical Information of China (English)

    Jilili; Abuduwaili

    2010-01-01

    In many arid and semiarid regions,saline playas represent a significant source of unconsoli-dated sediments available for aeolian transport,and severe saline dust storms occur frequently due to human disturbance.In this study,saline dust storms are reviewed systematically from the aspects of con-cept,general characteristics,conditions of occurrence,distribution and ecological impact.Our researches showed that saline dust storms are a kind of chemical dust storm originating in dry lake beds in arid and semiarid regions;large areas of unconsolidated saline playa sediments and frequent strong winds are the basic factors to saline dust storm occurrence;there are differentiation characteristics in deposition flux and chemical composition with wind-blown distance during saline dust storm diffusion;and saline dust storm diffusion to some extent increases glacier melt and results in soil salinization in arid regions.An under-standing of saline dust storms is important to guide disaster prevention and ecological rehabilitation.

  13. Characteristics of the volatile organic compounds -- Arid Integrated Demonstration Site

    International Nuclear Information System (INIS)

    The Volatile Organic Compounds -- Arid Integrated Demonstration Program (VOC-Arid ID) is targeted at demonstration and testing of technologies for the evaluation and cleanup of volatile organic compounds and associated contaminants at arid DOE sites. The initial demonstration site is an area of carbon tetrachloride (CCl4) contamination located near the center of the Hanford Site. The movement of CCl4 and other volatile organic contaminants in the subsurface is very complex. The problem at the Hanford Site is further complicated by the concurrent discharge of other waste constituents including acids, lard oil, organic phosphates, and transuranic radionuclides. In addition, the subsurface environment is very complex, with large spatial variabilities in hydraulic properties. A thorough understanding of the problem is essential to the selection of appropriate containment, retrieval, and/or in situ remedial technologies. The effectiveness of remedial technologies depends on knowing where the contaminants are, how they are held up in a given physical and chemical subsurface environment; and knowing the physical, chemical, and microbiological changes that are induced by the various remedial technologies

  14. Assessment of the Current State of Agropastoral Landscapes in Semi-Arid Areas of the Republic of Kalmykia with Application of Gis-Technologies

    Directory of Open Access Journals (Sweden)

    Mushaeva Kermen Batnasunovna

    2015-04-01

    Full Text Available The state of lands in arid areas of southern Russia is entirely dependent on the state of natural steppe, dry steppe and semi-desert ecosystems. The study of vegetation traditionally enjoys a commanding position in synecological studies, because plant communities form the framework of terrestrial ecosystems. In this paper we give a detailed geobothanical description of the test plots made as a result of field research in the semi-desert areas of Kalmykia. In addition, we obtained photo samples of soils that were subsequently processed, analyzed and entered into the database of soils and used as an identifier of rangeland degradation, located in the semi-arid zone of the country. The creation of this database will improve the quality of remote sensing in the region. In the course of computer processing of materials using GIS technology, the geoinformation analysis of land degradation in the studied territory was held, and the area of these lands according to the levels of degradation was calculated.

  15. Identifying environmental features for land management decisions

    Science.gov (United States)

    1984-01-01

    Multivariate statistical analysis and imaging processing techniques are being applied to the study of arid/semiarid environments, with emphasis on desertification. Field level indicators of land-soil biota degradation are being sifted out with staging up to the low aircraft reconnaissance level, to LANDSAT TM & MSS, and even to the AVHRR level. Three completed projects are reviewed: riparian habitat on the Humboldt River floodplain, Salt Lake County Urban expansion detection, and salinization/desertification detection in the delta area. Beginning projects summarized include: comparative condition of rangeland in Rush Valley; modeling a GIS/remote sensing data base for Cache County; universal soil loss equation applied to Pinyon-Juniper; relating MSS to ground radiometry near Battle Mountain; and riparian habitat mapping on Mary's River, Nevada.

  16. Seasonal and interannual variation of radiation and energy fluxes over a rain-fed cropland in the semi-arid area of Loess Plateau, northwestern China

    Science.gov (United States)

    Chen, Xing; Yu, Ye; Chen, Jinbei; Zhang, Tangtang; Li, Zhenchao

    2016-07-01

    Understanding the land-atmosphere interactions over the semi-arid area of Loess Plateau is important due to its special climate and unique underlying surface. In this study, two years' micrometeorological and energy flux observations from the Pingliang Land Surface Process & Severe Weather Research Station, CAS were used to investigate the seasonal and interannual variations of radiation budget and energy fluxes over a rain-fed cropland in the semi-arid area of Loess Plateau, with an emphasis on the influence of rain, soil moisture and agricultural production activities (such as crop type and harvest time) on the energy partitioning as well as the surface energy balance. The results revealed large annual variations in the seasonal distribution of precipitation, which gave rise to significant seasonal and interannual variations in soil moisture. Soil moisture was the main factor affecting radiation budget and energy partitioning. There was a negatively linear relationship between the albedo and the soil moisture. The main consumer of available energy varied among months and years with an apparent water stress threshold value of ca. 0.12 m3 m- 3, and the evapotranspiration was suppressed especially during the growing season. On an annual scale, the largest consumer of midday net radiation was sensible heat flux in 2010-2011, while it was latent heat flux in 2011-2012, which accounted for about 35% and 40% of the net radiation, respectively. The agricultural activity altered the sensitivity and variability of albedo to soil moisture, as well as energy partitioning patterns. The surface energy budget closures during Dec. 2010-Nov. 2011 and Dec. 2011-Nov. 2012 were 77.6% and 73.3%, respectively, after considering the soil heat storage. The closure was comparable to other sites in ChinaFLUX (49% to 81% of 8 sites). The patterns of energy partitioning and the water stress threshold found in the semi-arid cropland could be used to evaluate and improve land surface models.

  17. Response of vegetation to drought time-scales across global land biomes.

    Science.gov (United States)

    Vicente-Serrano, Sergio M; Gouveia, Célia; Camarero, Jesús Julio; Beguería, Santiago; Trigo, Ricardo; López-Moreno, Juan I; Azorín-Molina, César; Pasho, Edmond; Lorenzo-Lacruz, Jorge; Revuelto, Jesús; Morán-Tejeda, Enrique; Sanchez-Lorenzo, Arturo

    2013-01-01

    We evaluated the response of the Earth land biomes to drought by correlating a drought index with three global indicators of vegetation activity and growth: vegetation indices from satellite imagery, tree-ring growth series, and Aboveground Net Primary Production (ANPP) records. Arid and humid biomes are both affected by drought, and we suggest that the persistence of the water deficit (i.e., the drought time-scale) could be playing a key role in determining the sensitivity of land biomes to drought. We found that arid biomes respond to drought at short time-scales; that is, there is a rapid vegetation reaction as soon as water deficits below normal conditions occur. This may be due to the fact that plant species of arid regions have mechanisms allowing them to rapidly adapt to changing water availability. Humid biomes also respond to drought at short time-scales, but in this case the physiological mechanisms likely differ from those operating in arid biomes, as plants usually have a poor adaptability to water shortage. On the contrary, semiarid and subhumid biomes respond to drought at long time-scales, probably because plants are able to withstand water deficits, but they lack the rapid response of arid biomes to drought. These results are consistent among three vegetation parameters analyzed and across different land biomes, showing that the response of vegetation to drought depends on characteristic drought time-scales for each biome. Understanding the dominant time-scales at which drought most influences vegetation might help assessing the resistance and resilience of vegetation and improving our knowledge of vegetation vulnerability to climate change.

  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. 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.

  20. 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.

  1. Grazing impacts on the susceptibility of rangelands to wind erosion: The effects of stocking rate, stocking strategy and land condition

    Science.gov (United States)

    Aubault, Hélène; Webb, Nicholas P.; Strong, Craig L.; McTainsh, Grant H.; Leys, John F.; Scanlan, Joe C.

    2015-06-01

    An estimated 110 Mt of dust is eroded by wind from the Australian land surface each year, most of which originates from the arid and semi-arid rangelands. Livestock production is thought to increase the susceptibility of the rangelands to wind erosion by reducing vegetation cover and modifying surface soil stability. However, research is yet to quantify the impacts of grazing land management on the erodibility of the Australian rangelands, or determine how these impacts vary among land types and over time. We present a simulation analysis that links a pasture growth and animal production model (GRASP) to the Australian Land Erodibility Model (AUSLEM) to evaluate the impacts of stocking rate, stocking strategy and land condition on the erodibility of four land types in western Queensland, Australia. Our results show that declining land condition, over stocking, and using inflexible stocking strategies have potential to increase land erodibility and amplify accelerated soil erosion. However, land erodibility responses to grazing are complex and influenced by land type sensitivities to different grazing strategies and local climate characteristics. Our simulations show that land types which are more resilient to livestock grazing tend to be least susceptible to accelerated wind erosion. Increases in land erodibility are found to occur most often during climatic transitions when vegetation cover is most sensitive to grazing pressure. However, grazing effects are limited during extreme wet and dry periods when the influence of climate on vegetation cover is strongest. Our research provides the opportunity to estimate the effects of different land management practices across a range of land types, and provides a better understanding of the mechanisms of accelerated erosion resulting from pastoral activities. The approach could help further assessment of land erodibility at a broader scale notably if combined with wind erosion models.

  2. Land Competition and Land-Use Change:

    DEFF Research Database (Denmark)

    Vongvisouk, Thoumthone

    hand, the government is also working to increase national economic growth by promoting private-sector investment in both agriculture and forest resources – two sectors that compete for the same areas intended for protection. This thesis explores how these contradictory drivers of land-use changes...... claims on land and forest resources and for increasing forest conservation. Not only do these land-use changes impact rural people’s livelihoods, but they also impact their access to land and natural forest resources. In general, rural people in the study area perceive that they have improved......Land competition and land-use changes are taking place in many developing countries as the demand for land increases. These changes are leading to changes in the livelihood conditions of rural people. The Government of Laos (GoL), on the one hand, aims to increase forest protection. On the other...

  3. Have Changes to Unused Land in China Improved or Exacerbated Its Environmental Quality in the Past Three Decades?

    Directory of Open Access Journals (Sweden)

    Ling Yi

    2016-02-01

    Full Text Available Inappropriate land use has caused a series of environmental disasters such as floods and sand storms, and some of them involved unused land changes with highly localized distributions in arid and semi-arid regions with fragile ecosystems. As the third-rank category of first-level land use/cover in China, unused land (UL is now playing an increasingly important role in protection of the natural environment and sustainable utilization of land resources. In this article, we assessed the effects on regional eco-environments employing a quantitative EL (ecological effect index model, which can be used to evaluate and represent the contribution of UL changes to the eco-environmental quality. Results show that UL changes generally contributed to the deterioration of eco-environmental quality during the study period. Some major contributors to improving eco-environmental quality were transformation of sandy land and saline-alkali lands to grasslands, expansion of water bodies in UL areas, and reclamation of farmland in UL areas (except for marsh lands. In contrast, the main contributors to worsening eco-environmental quality were grassland degradation to UL (except marshes, reclamation of marsh areas, and shrinkage of water bodies to leave desert or saline-alkali land. Some suggestions are provided about UL management, utilization, and protection issues.

  4. Concentrations and Fractionation of Carbon, Iron, Sulfur, Nitrogen and Phosphorus in Mangrove Sediments Along an Intertidal Gradient (Semi-Arid Climate, New Caledonia)

    OpenAIRE

    Jonathan Deborde; Cyril Marchand; Nathalie Molnar; Luc Della Patrona; Tarik Meziane

    2015-01-01

    In mangrove ecosystems, strong reciprocal interactions exist between plant and substrate. Under semi-arid climate, Rhizophora spp. are usually predominant, colonizing the seashore, and Avicennia marina develops at the edge of salt-flats, which is the highest zone in the intertidal range. Along this zonation, distribution and speciation of C, Fe, S, N, and P in sediments and pore-waters were investigated. From the land-side to the sea-side of the mangrove, sediments were characterized by I/ in...

  5. Spatiotemporal analysis and trends of aridity of Iberian Peninsula (1960-2010)

    Science.gov (United States)

    Paniagua, Luis L.; García, Abelardo; Moral, Francisco J.; Rebollo, Francisco J.

    2016-04-01

    In this study the aridity of the Iberian Peninsula was analysed, taking into account 45 stations in Spain and Portugal from 1960 to 2010. The De Martonne Index was considered. The goal of this study was to explore the spatial distribution and to determine monotonic trends and shift changes in annual aridity by using the Mann-Kendall test and the Seńs estimator. The spatially interpolated maps of the aridity indice were generated using the ordinary kriging algorithm in a geographic information system (GIS) environment. A great variability for Martonne Index was found, gathering from semiarid climates to extremely humid, although the former being the dominant type. 41 temporal series showed decreasing tendencies, 15 of them significant, belonging to all climate types, which indicates a increase in aridity during the research period. A shift in the aridity tendency has been observed around 1979, and a period of greater aridity started since.

  6. VOC-Arid Integrated Demonstration guide to preparation of demonstration documents

    International Nuclear Information System (INIS)

    This guide has been prepared by Demonstration Operations of the Volatile Organic Compound-Arid Integrated Demonstration (VOC-Arid ID). Its purpose is to describe demonstration documents, designate responsibilities for these documents, and guide the Principal Investigator (PI) and others in their preparation. The main emphasis of this guide is to describe the documentation required of the PI. However, it does cover some of the responsibilities of other members of the VOC-Arid ID team. The VOC-Arid ID is one of several US Department of Energy (DOE) integrated demonstrations designed to support the demonstration of emerging environmental management and restoration technologies. The principal objective of the VOC-Arid ID is to identify, develop, and demonstrate new and innovative technologies for environmental restoration at arid or semiarid sites containing volatile organic compounds with or without associated contamination (e.g., radionuclides and metals)

  7. Analysing the Effects of Different Land Cover Types on Land Surface Temperature Using Satellite Data

    Science.gov (United States)

    Şekertekin, A.; Kutoglu, Ş. H.; Kaya, S.; Marangoz, A. M.

    2015-12-01

    Monitoring Land Surface Temperature (LST) via remote sensing images is one of the most important contributions to climatology. LST is an important parameter governing the energy balance on the Earth and it also helps us to understand the behavior of urban heat islands. There are lots of algorithms to obtain LST by remote sensing techniques. The most commonly used algorithms are split-window algorithm, temperature/emissivity separation method, mono-window algorithm and single channel method. In this research, mono window algorithm was implemented to Landsat 5 TM image acquired on 28.08.2011. Besides, meteorological data such as humidity and temperature are used in the algorithm. Moreover, high resolution Geoeye-1 and Worldview-2 images acquired on 29.08.2011 and 12.07.2013 respectively were used to investigate the relationships between LST and land cover type. As a result of the analyses, area with vegetation cover has approximately 5 ºC lower temperatures than the city center and arid land., LST values change about 10 ºC in the city center because of different surface properties such as reinforced concrete construction, green zones and sandbank. The temperature around some places in thermal power plant region (ÇATES and ZETES) Çatalağzı, is about 5 ºC higher than city center. Sandbank and agricultural areas have highest temperature due to the land cover structure.

  8. ANALYSING THE EFFECTS OF DIFFERENT LAND COVER TYPES ON LAND SURFACE TEMPERATURE USING SATELLITE DATA

    Directory of Open Access Journals (Sweden)

    A. Şekertekin

    2015-12-01

    Full Text Available Monitoring Land Surface Temperature (LST via remote sensing images is one of the most important contributions to climatology. LST is an important parameter governing the energy balance on the Earth and it also helps us to understand the behavior of urban heat islands. There are lots of algorithms to obtain LST by remote sensing techniques. The most commonly used algorithms are split-window algorithm, temperature/emissivity separation method, mono-window algorithm and single channel method. In this research, mono window algorithm was implemented to Landsat 5 TM image acquired on 28.08.2011. Besides, meteorological data such as humidity and temperature are used in the algorithm. Moreover, high resolution Geoeye-1 and Worldview-2 images acquired on 29.08.2011 and 12.07.2013 respectively were used to investigate the relationships between LST and land cover type. As a result of the analyses, area with vegetation cover has approximately 5 ºC lower temperatures than the city center and arid land., LST values change about 10 ºC in the city center because of different surface properties such as reinforced concrete construction, green zones and sandbank. The temperature around some places in thermal power plant region (ÇATES and ZETES Çatalağzı, is about 5 ºC higher than city center. Sandbank and agricultural areas have highest temperature due to the land cover structure.

  9. Comparison of long-term stability of containment systems for residues and wastes contaminated with naturally occurring radionuclides at an arid site and two humid sites

    International Nuclear Information System (INIS)

    The long-term stability of near-surface containment systems designed for the management of radioactive wastes and residues contaminated with naturally occurring radionuclides are compared at the three different sites. The containment designs are: (1) a diked 8.9-m high mound, including a 3.2-m layered cap at a site (humid) near Lewiston, New York, (2) a 6.8-m-high mound, including a similar 3.2-m cap at a site (humid) near Oak Ridge, Tennessee, and (3) 4.8-m deep trenches with 3.0-m backfilled caps at a site (arid) near Hanford, Washington. Geological, hydrological, and biological factors affecting the long-term (1000-year) integrity of the containment systems at each site are examined, including: erosion, flooding, drought, wildfire, slope and cover failure, plant root penetration, burrowing animals, other soil-forming processes, and land-use changes. For the containment designs evaluated, releases of radon-222 at the arid site are predicted to be several orders of magnitude higher than at the two humid sites - upon initial burial and at 1000 years (after severe erosion). Transfer of wastes containing naturally occurring radionuclides from a humid to an arid environment offers little or no advantage relative to long-term stability of the containment system and has a definite disadvantage in terms of gaseous radioactive releases. 26 references, 3 figures, 4 tables

  10. 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

  11. 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...

  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. ARID1A immunohistochemistry improves outcome prediction in invasive urothelial carcinoma of urinary bladder.

    Science.gov (United States)

    Faraj, Sheila F; Chaux, Alcides; Gonzalez-Roibon, Nilda; Munari, Enrico; Ellis, Carla; Driscoll, Tina; Schoenberg, Mark P; Bivalacqua, Trinity J; Shih, Ie-Ming; Netto, George J

    2014-11-01

    AT-rich interactive domain 1A (ARID1A) is tumor suppressor gene that interacts with BRG1 adenosine triphosphatase to form a SWI/SNF chromatin remodeling protein complex. Inactivation of ARID1A has been described in several neoplasms, including epithelial ovarian and endometrial carcinomas, and has been correlated with prognosis. In the current study, ARID1A expression in urothelial carcinoma (UC) of the bladder and its association with clinicopathological parameters and outcome are addressed. Five tissue microarrays were constructed from 136 cystectomy specimens performed for UC at our institution. Nuclear ARID1A staining was evaluated using immunohistochemistry. An H-score was calculated as the sum of the products of intensity (0-3) multiplied by extent of expression (0%-100%). Average H-score per case was used for statistical analysis. ARID1A expression was categorized in low and high using Youden index to define the cut point. ARID1A expression significantly increased from normal to noninvasive UC to invasive UC. For both tumor progression and cancer death, Youden index yielded an H-score of 288 as the optimal cut point for ARID1A expression. Low ARID1A expression showed a tendency for lower risk of tumor progression and cancer mortality. Adding ARID1A expression to pathologic features offers a better model for predicting outcome than pathologic features alone. Low ARID1A expression was more frequently seen in earlier stage disease. There was a tendency for low ARID1A expression to predict better outcome. More importantly, the findings indicate that adding ARID1A expression to pathologic features increases the goodness of fit of the predictive model. PMID:25175170

  14. A Proposal on the Restoration of Nostoc flagelliforme for Sustainable Improvement in the Ecology of Arid Steppes in China

    Directory of Open Access Journals (Sweden)

    Xiang Gao

    2016-06-01

    Full Text Available Nostoc flagelliforme, a filamentous nitrogen-fixing cyanobacterium, is widely distributed in arid steppes of the west and northwestern parts of China. However, as a food delicacy this species has been overexploited from 1970 to 2000. Moreover, overgrazing, land reclamation and the removal of medicinal herbs have caused severely reduced vegetation coverage there. In this communication, a badly damaged but slowly rehabilitating N. flagelliforme-inhibiting steppe is described, and the rehabilitation of desertified steppes by the renewed growth of N. flagelliforme is proposed. The restoration of this dominant nitrogen supplier would be an ecologically sustainable solution for supplementing current measures already taken in the desertified regions. In addition, a goal of 50%–60% vegetation coverage is proposed by the N. flagelliforme restoration.

  15. Building resilience to social-ecological change through farmers' learning practices in semi-arid Makueni County Kenya

    Science.gov (United States)

    Ifejika Speranza, Chinwe; Kiteme, Boniface; Kimathi Mbae, John; Schmude, Miron

    2015-04-01

    Social-ecological change is resulting in various risks and opportunities to farmers, which they address through complex multi-strategies to sustain their agricultural-based livelihoods and agricultural landscapes. This paper examines how various stakeholders such as research and government organisations, local and international non-governmental organisations, private companies, farmer groups, individual actors and farmers draw on scientific, external and localised knowledge to address the needs of farmers in sustainable land management and food production. What is the structure of collaboration between the various actors and how does this influence the potential for learning, not only for the farmers but also for other stakeholders? How does the supplied knowledge meet farmers' knowledge needs and demands for sustainable land management and food production? To what extent and how is knowledge co-produced among the various stakeholders? What different types of learning can be identified and what are their influences on farmers' sustainable land management practices? How does farmer learning foster the resilience of agricultural landscapes? Answers to these questions are sought through a case study in the semi-arid areas of Makueni County, Kenya. Particular environmental risks in the study area relate to recurrent droughts and flooding, soil erosion and general land degradation. Opportunities in the study area arise short-term due to more conducive rainfall conditions for crop and vegetation growth, institutional arrangements that foster sustainable land management such as agroforestry programmes and conservation agriculture projects. While farmers observe changes in their environment, they weigh the various risks and opportunities that arise from their social-ecological context and their own capacity to respond leading to the prioritization of certain adaptations relative to others. This can mean that while certain farmers may have knowledge on sustainable land

  16. Review of several problems on the study of eco-hydrological processes in arid zones

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Ecosystem degradation is a common and cardinal environmental problem in arid zones. The change in the eco-hydrological processes is the basic cause responsible for such a problem. The study on the eco-hydrological processes in arid zones has become a forefront and focus of the eco-environmental research. Recent studies on eco-hydrological processes in arid zones show that the primary vegetation pattern and its eco-hydrological effect are of the most stable state of the ecosystem in arid zones. Special water absorption ways of plants in arid zones and the hydraulic lift and reverse hydraulic lift functions of some plants are the key mechanisms to maintain the stability of the ecosystem in arid zones. In the case of water shortage, ensuring ecological water requirement and maintaining proper ecological ground- water table are the prerequisite to keep healthful operation of the ecosystem in arid zones. The paper reviews some advances in the study of eco-hydrological processes in arid zones. It puts forward the concepts of critical ecological water requirement, optimal ecological water requirement and saturated ecological water requirement, and discusses their determination methods. It also emphasizes that the studies on natural vegetation pattern and eco-hydrological effect, on plants with hydraulic lift function, on water sources for plant absorption, on ecological water requirement and ecological groundwater table for different plant species should be strengthened to determine the species composition and pattern suitable for the restoration and reestablishment of vegetation in different arid zones in China.

  17. Targeting EZH2 methyltransferase activity in ARID1A mutated cancer cells is synthetic lethal

    Science.gov (United States)

    Biter, Benjamin G.; Aird, Katherine M.; Garipov, Azat; Li, Hua; Amatangelo, Michael; Kossenkov, Andrew V.; Schultz, David C.; Liu, Qin; Shih, Ie-Ming; Conejo-Garcia, Jose R.; Speicher, David W.; Zhang, Rugang

    2015-01-01

    ARID1A, a chromatin remodeler, shows one of the highest mutation rates across many cancer types. Notably, ARID1A is mutated in over 50% of ovarian clear cell carcinomas, which currently has no effective therapy. To date, clinically applicable targeted cancer therapy based on ARID1A mutational status has not been described. Here we show that inhibition of the EZH2 methyltransferase acts in a synthetic lethal manner in ARID1A mutated ovarian cancer cells. ARID1A mutational status correlates with response to the EZH2 inhibitor. We identified PIK3IP1 as a direct ARID1A/EZH2 target, which is upregulated by EZH2 inhibition and contributes to the observed synthetic lethality by inhibiting PI3K/AKT signaling. Significantly, EZH2 inhibition causes regression of ARID1A mutated ovarian tumors in vivo. Together, these data demonstrate for the first time a synthetic lethality between ARID1A mutation and EZH2 inhibition. They indicate that pharmacological inhibition of EZH2 represents a novel treatment strategy for ARID1A mutated cancers. PMID:25686104

  18. Impact of Reforestation on Local Climate and Environment in a Semi-arid Urban Valley, Northwestern China

    Science.gov (United States)

    Xia, D.; Yu, Y.; He, J.

    2015-12-01

    Since 1999 Chinese government has invested more than 800 million Yuan to reforest the southern and the northern mountains surrounding urban Lanzhou - a typical semi-arid city located in a river valley, Northwestern China. Until 2009 obvious land use change occurred, with 69.2% of the reforested area been changed from grasslands, croplands, barren or sparsely vegetated land to closed shrublands and 20.6% been changed from closed shrublands, grasslands, and croplands to forests. This study assesses the impact of these changes on local climate and environment in winter using WRF (Weather Research & Forecasting) model incorporated with high-resolution remotely sensed land cover data for 1999 and 2009 and the FLEXible PARTicle (FLEXPART) dispersion model. Results indicate that the changes in albedo, surface exchange coefficient and surface soil heat conductivity related to the reforestation led to the changes in surface net radiation and the surface energy partitioning, which in turn affected the meteorology fields and enhanced the mountain-valley wind circulation. The amount of air exchanged between the valley and the outside increased after reforestation during the day, with the largest increase of 10 %, while it changed little during the night on winter sunny day with no snow cover. The sensitivity analysis using FLEXPART-WRF model indicates that the reforestation affected the spatial distribution of pollutants and slightly improved the urban air quality in winter. And the greening program of Lanzhou has special reference to other valley urbans.

  19. Variations in Soil Salinity and Riparian Vegetation Coverage as Indicators of Stress in an Arid Watershed

    Science.gov (United States)

    Gutierrez, M.; Mickus, K.; Johnson, E.

    2003-12-01

    Soil salinity and riparian vegetation coverages of an arid area in northern Mexico through time were investigated. The study area comprises a 10 km segment of the lower Rio Conchos and surrounding undeveloped, non-irrigated land. The amount of area affected by salinity and the type of salinity were determined using EC (electrical conductivity) in conjunction with satellite images and corroborated by field analysis. The soil salinity derived from the remote sensing data was tied to precipitation, greenness of vegetation and water level of a nearby reservoir. The most appropriate method to assess soil salinity was found to be the selective principal component (SPCA) technique of Chavez and Kwarteng while the techniques utilized to discriminate vigorously-growing vegetation were tasseled cap transformation and the normalized difference vegetation index (NDVI). With this region undergoing a severe drought for the last ten years, the response of different parts of the ecosystem and changes in vegetation that so closely affect wildlife and other natural resources in this area can be better evaluated.

  20. Trial of Various Methods in Arid Soil at the Inshas Centre near Cairo

    International Nuclear Information System (INIS)

    Two often-suggested methods for detecting land mines are sensitive to the presence of soil moisture. These are Ground-Penetrating Radar (GPR) and neutron methods. Moisture makes soil more conducting, which reduces the skin depth in soil and hence the depth at which GPR can detect mines; hydrogen in water interferes with neutron penetration and hence their ability to detect mines at depth. Since North Africa, and Egypt in particular, is arid except for a few months each year, this might be a promising area for such techniques. A trial of these methods in dry conditions on de-fused but otherwise real landmines has therefore been organised to check how well GPR and neutron detectors perform in dry conditions. Six APMs of four types, and ATMs of five types, were available. Detectors from Europe, South Africa and Egypt were used. Data obtained from blind trials with two GPRs and two neutron detectors will be presented, along with some independent magnetometer results. (author)

  1. Human-Wildlife Conflicts in Arid Areas of Western India: Strategies for Mutual Co-Existence

    Directory of Open Access Journals (Sweden)

    Darshana Patel

    2014-04-01

    Full Text Available The study has been carried out in the North Gujarat region of Gujarat state, Western India which represents unique habitats from arid regions to dry deciduous forests with annual rainfall ranging from 25-125 cms. Human-wildlife conflicts are intensifying owing to increase in human population and destruction of wildlife habitats. In the present study we characterized and classified the conflicts, identified zones with acute conflicts and evaluated the economic loss to the local villagers due to such humanwildlife conflicts. Sampling methods mainly included village surveys for interviewing locals who are affected by wildlife damage. The information was overlaid on the existing digital land use data to identify landscape characteristics associated with wildlife occupancy in the region. The result depicts that 80% of total damage in seasonal crop is caused by wild ungulates. Wild animals like Blue bull, Wild boar and Porcupine are reported as a chief crop raider. The Leopard is the only big cat occurring in the region reported to cause human injury and livestock predation. Sloth bear attacks on human are very common in some part of the study area. Conflicts are more severe around unprotected forests while high intensity of conflicts was recorded on the fringes of the forests

  2. The oasis effect and summer temperature rise in arid regions - case study in Tarim Basin

    Science.gov (United States)

    Hao, Xingming; Li, Weihong; Deng, Haijun

    2016-10-01

    This study revealed the influence of the oasis effect on summer temperatures based on MODIS Land Surface Temperature (LST) and meteorological data. The results showed that the oasis effect occurs primarily in the summer. For a single oasis, the maximum oasis cold island intensity based on LST (OCILST) was 3.82 °C and the minimum value was 2.32 °C. In terms of the annual change in OCILST, the mean value of all oases ranged from 2.47 °C to 3.56 °C from 2001 to 2013. Net radiation (Rn) can be used as a key predictor of OCILST and OCItemperature (OCI based on air temperature). On this basis, we reconstructed a long time series (1961–2014) of OCItemperature and Tbase(air temperature without the disturbance of oasis effect). Our results indicated that the reason for the increase in the observed temperatures was the significant decrease in the OCItemperature over the past 50 years. In arid regions, the data recorded in weather stations not only underestimated the mean temperature of the entire study area but also overestimated the increasing trend of the temperature. These discrepancies are due to the limitations in the spatial distribution of weather stations and the disturbance caused by the oasis effect.

  3. 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)

  4. 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.

  5. An ecological engineering approach for keeping water from reaching interred wastes in arid or semiarid regions

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, J.E. [Idaho State Univ., Pocatello, ID (United States)

    1997-12-31

    This paper describes application of a soil-plant cover system (SPCS) to preclude water from reaching interred wastes in arid and semiarid regions. Where potential evapotranspiration far exceeds precipitation, water can be kept from reaching buried wastes by (1) providing a sufficiently deep cap of soil to store precipitation that falls while plants are dormant and (2) maintaining plant cover to deplete soil moisture during the growing season, thereby emptying the storage reservoir. Research at the Idaho National Engineering Laboratory (INEL) has shown that 2 m of soil is adequate to store moisture from snowmelt and spring rains. Healthy stands of perennial grasses and shrubs adapted to the INEL climate use all available soil moisture, even during a very wet growing season. However, burrowing by small mammals or ants may affect the performance of a SPCS by increasing infiltration of water. Intrusion barriers of gravel and cobble can be used to restrict burrowing, but emplacement of such barriers affects soil moisture storage and plant rooting depths. A replicated field experiment to investigate the implications of those effects is in progress. Incorporation of an SPCS should be considered in the design of isolation barriers for shallow land burial of hazardous wastes in and regions.

  6. Ecosystem services provided by agricultural terraces in semi-arid climates.

    Science.gov (United States)

    Romero-Díaz, Asunción; Díaz-Pereira, Elvira; Boix-Fayos, Carolina; de Vente, Joris

    2016-04-01

    Since ancient times, agricultural terraces are common features throughout the world, especially on steep slope gradients. Nowadays many terraces have been abandoned or removed and few new terraces are build due to increased mechanisation and intensification of agriculture. However, terraces are amongst the most effective soil conservation practices, reducing the slope gradient and slope length, as well as runoff rate and soil erosion, and without terraces, it would be impossible to cultivate on many hillslopes. Moreover, their scenic interest is undeniable, as in some cases, terraced slopes have even become part of UNESCO World Heritage. In order to highlight the potential benefits, requirements and limitations of terraces, we reviewed different types of sustainable land management practices related to terraces and characterised their implications for provisioning, regulating, supporting, and cultural ecosystem services. We centred our review on terraces in semi-arid environments worldwide, as were documented in the WOCAT (World Overview of Conservation Approaches and Technologies) database. Our results show that the most important ecosystem services provided by terraces relate to regulation of the on-site and off-site effects of runoff and erosion, and maintenance of soil fertility and vegetation cover. The presence of terraces also favours the provision of food, fiber, and clean water. In short, our results stress the crucial environmental, geomorphological and hydrological functions of terraces that directly relate to improving the quality of life of the people that use them. These results highlight the need for renewed recognition of the value of terraces for society, their preservation and maintenance.

  7. Laws of the Land

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    With illegal land requisition on the rise, China is attempting to clamp down at the local level with new supervisory measures The complaints about land rights violations are many, and growing. In China's central Hebei Province, a peasant told land regulators that "a person has started mining in our village before securing land use rights from the government." The peasant added that the local land resources management department, without getting permission

  8. Developing an Understanding of Vegetation Change and Fluvial Carbon Fluxes in Semi-Arid Environments

    Science.gov (United States)

    Puttock, A.; Brazier, R. E.; Dungait, J. A. J.; Bol, R.; Macleod, C. J. A.

    2012-04-01

    Dryland environments are estimated to cover around 40% of the global land surface (Okin et al, 2009) and are home to approximately 2.5 billion people (Reynolds et al. 2007). Many of these areas have recently experienced extensive land degradation. One such area and the focus of this project is the semi-arid US Southwest, where degradation over the past 150 years has been characterised by the invasion of woody vegetation into grasslands. Transition from grass to woody vegetation results in a change in ecosystem structure and function (Turnbull et al, 2008). Structural change is typically characterised by an increased heterogeneity of soil and vegetation resources, associated with reduced vegetation coverage and an increased vulnerability to soil erosion and the potential loss of key nutrients to adjacent fluvial systems. Such loss of resources may impact heavily upon the amount of carbon that is sequestered by these environments and the amount of carbon that is lost as the land becomes more degraded. Therefore, understanding these vegetation transitions is significant for sustainable land use and global biogeochemical cycling. This project uses an ecohydrological approach, monitoring natural rainfall-runoff events over six bounded plots with different vegetation coverage. The experiment takes advantage of a natural abundance stable 13C isotope shift from C3 piñon-juniper (Pinus edulis-Juniperus monosperma) mixed stand through a C4 pure-grass (Bouteloua eriopoda) to C3 shrub (Larrea tridentata). Data collected quantify fluvial fluxes of sediment and associated soil organic matter and carbon that is lost from across the grass-to-shrub and grass-to-woodland transition (where change in space is taken to indicate a similar change through time). Results collected during the 2010 and 2011 monsoon seasons will be presented, illustrating that soil and carbon losses are greater as the ecosystem becomes more dominated by woody plants. Additionally this project utilises novel

  9. Land land (6/4 e)

    OpenAIRE

    2011-01-01

    Laulun sanat: Land, land, o land! Se, Herrens hand är nu uträckt, Och hafver dig betäckt: Själ, själ, o själ! Beskåd', Hvad nåd, Hvad tröst och frid Dig sändes nid Från nådens stol, Rättfardighetens sol.

  10. The effects of clouds and aerosols on net ecosystem CO2 exchange over semi-arid Loess Plateau of Northwest China

    Directory of Open Access Journals (Sweden)

    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.

  11. Factors Affecting Adoption of Agroforestry Farming System as a Mean for Sustainable Agricultural Development and Environment Conservation in Arid Areas of Northern Kordofan State, Sudan

    International Nuclear Information System (INIS)

    Arid and semi-arid areas represent about 60 percent of Sudan total area. One of the main environmental problems in the arid and semi-arid areas is diffraction's which reduces the natural potential of the already fragile ecosystems and renders rural people vulnerable to food shortages, the vagaries of weather and natural disasters. Deforestation which is considered one of the most critical environmental problems facing the world is one of the main causes of diffraction's. Between the years 1990 and 2005 Sudan lost about 8.8 millions hectares of forests, which represents 11%, of its forests mainly because of subsistence activities such as overgrazing, trees cutting and expansion of traditional agriculture. One of the areas that are very much affected by diffraction's is Northern Kordofan State. To rescue the situation the government of Sudan, with assistance from the United Nations Development Program (UNDP) and some donors, implemented a project that aimed primarily at restocking Acacia Senegal trees in Northern Kordofan State. This study is intended to explore the factors that caused differential rate of farmers' adoption rate of the Acacia Senegal based agroforestry farming system. The study data was collected from a clustered random sample of 300 farmers, through face to face interviews using a questionnaire that was pre-tested and validated. Frequency distribution and multiple regression analysis were used to analyze the data. It has been found that farmers' adoption of agroforestry farming system in Northern Kordofan state was significantly affected by the farmers' level of formal education, contact with extension agents, level of environmental awareness, cosmopoliteness, total area of owned land and extent of social participation. (author)

  12. Formation of land administration system and land use as an economic function of the land ownership

    OpenAIRE

    Tretiak, N.

    2014-01-01

    This paper deals with manifestation forms of land management and land use as an economic function of the property rights to land. The need to form an integrated system of land management and land use in Ukraine as an economic function of land ownership has been grounded. A model of comprehensive multifunctional system of land management and land use has been suggested

  13. 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

  14. Meaningful traits for grouping plant species across arid ecosystems.

    Science.gov (United States)

    Bär Lamas, Marlene Ivonne; Carrera, A L; Bertiller, M B

    2016-05-01

    Grouping species may provide some degree of simplification to understand the ecological function of plants on key ecosystem processes. We asked whether groups of plant species based on morpho-chemical traits associated with plant persistence and stress/disturbance resistance reflect dominant plant growth forms in arid ecosystems. We selected twelve sites across an aridity gradient in northern Patagonia. At each site, we identified modal size plants of each dominant species and assessed specific leaf area (SLA), plant height, seed mass, N and soluble phenol concentration in green and senesced leaves at each plant. Plant species were grouped according with plant growth forms (perennial grasses, evergreen shrubs and deciduous shrubs) and plant morphological and/or chemical traits using cluster analysis. We calculated mean values of each plant trait for each species group and plant growth form. Plant growth forms significantly differed among them in most of the morpho-chemical traits. Evergreen shrubs were tall plants with the highest seed mass and soluble phenols in leaves, deciduous shrubs were also tall plants with high SLA and the highest N in leaves, and perennial grasses were short plants with high SLA and low concentration of N and soluble phenols in leaves. Grouping species by the combination of morpho-chemical traits yielded 4 groups in which species from one growth form prevailed. These species groups differed in soluble phenol concentration in senesced leaves and plant height. These traits were highly correlated. We concluded that (1) plant height is a relevant synthetic variable, (2) growth forms adequately summarize ecological strategies of species in arid ecosystems, and (3) the inclusion of plant morphological and chemical traits related to defenses against environmental stresses and herbivory enhanced the potential of species grouping, particularly within shrubby growth forms. PMID:26897637

  15. Cover integrity in shallow land burial of low-level wastes: hydrology and erosion

    International Nuclear Information System (INIS)

    Applications of a state-of-the-art technology for simulating hydrologic processes and erosion affecting cover integrity at shallow land waste burial sites are described. A nonpoint source pollution model developed for agricultural systems has been adapted for application to waste burial sites in semiarid and arid regions. Applications include designs for field experiments, evaluation of slope length and steepness, evaluation of various soil types, and evaluation of vegetative cover influencing erosion rates and the water balance within the soil profile

  16. Ecological knowledge of hausa cultivators for the land degradation process in sahel, west africa

    OpenAIRE

    OYAMA, Shuichi

    2009-01-01

    The Hausa people living in the arid environment of the Republic of Niger cultivate pearl millet and cowpea. They face land degradation (desertification) problems in the cultivated fields. To avoid this problem, they carry trash as manure from their homesteads into the millet fields. The trash is called taki in the Hausa language. The taki mainly contains organic matter, such as plant residue and livestock excreta, and small amounts of low degradability materials, such as the worn-out clothing...

  17. An Approach for Simulating Soil Loss from an Agro-Ecosystem Using Multi-Agent Simulation: A Case Study for Semi-Arid Ghana

    Directory of Open Access Journals (Sweden)

    Biola K. Badmos

    2015-07-01

    Full Text Available Soil loss is not limited to change from forest or woodland to other land uses/covers. It may occur when there is agricultural land-use/cover modification or conversion. Soil loss may influence loss of carbon from the soil, hence implication on greenhouse gas emission. Changing land use could be considered actually or potentially successful in adapting to climate change, or may be considered maladaptation if it creates environmental degradation. In semi-arid northern Ghana, changing agricultural practices have been identified amongst other climate variability and climate change adaptation measures. Similarly, some of the policies aimed at improving farm household resilience toward climate change impact might necessitate land use change. The heterogeneity of farm household (agents cannot be ignored when addressing land use/cover change issues, especially when livelihood is dependent on land. This paper therefore presents an approach for simulating soil loss from an agro-ecosystem using multi-agent simulation (MAS. We adapted a universal soil loss equation as a soil loss sub-model in the Vea-LUDAS model (a MAS model. Furthermore, for a 20-year simulation period, we presented the impact of agricultural land-use adaptation strategy (maize cultivation credit i.e., maize credit scenario on soil loss and compared it with the baseline scenario i.e., business-as-usual. Adoption of maize as influenced by maize cultivation credit significantly influenced agricultural land-use change in the study area. Although there was no significant difference in the soil loss under the tested scenarios, the incorporation of human decision-making in a temporal manner allowed us to view patterns that cannot be seen in single step modeling. The study shows that opening up cropland on soil with a high erosion risk has implications for soil loss. Hence, effective measures should be put in place to prevent the opening up of lands that have high erosion risk.

  18. 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.

  19. Understanding land administration systems

    DEFF Research Database (Denmark)

    P. Williamson, Ian; Enemark, Stig; Wallace, Judy;

    2008-01-01

    in contributing to sustainable development, thirdly the changing nature of ownership and the role of land markets, and lastly a land management vision that promotes land administration in support of sustainable development and spatial enablement of society. We present here the first part of the paper. The second...... part focuses on the changing  role of ownership and the role of land markets, and a land management vision will be published in November issue of Coordinates. Udgivelsesdato: Oktober......This paper introduces basic land administration theory and highlights four key concepts that are fundamental to understanding modern land administration systems - firstly the land management paradigm and its influence on the land administration framework, secondly the role that the cadastre plays...

  20. Land management and development

    DEFF Research Database (Denmark)

    Enemark, Stig

    2006-01-01

    Land management is the process by which the resources of land are put into good effect. Land management encompasses all activities associated with the management of land that are required to achieve sustainable development. The concept of land includes properties and natural resources and thereby...... land related data. It is argued that development of such a model is important or even necessary for facilitating a holistic approach to the management of land as the key asset of any nation or jurisdiction.......Land management is the process by which the resources of land are put into good effect. Land management encompasses all activities associated with the management of land that are required to achieve sustainable development. The concept of land includes properties and natural resources and thereby...... encompasses the total natural and built environment. Land Administration Systems (LAS) are institutional frameworks complicated by the tasks they must perform, by national cultural, political and judicial settings, and by technology. This paper facilitates an overall understanding of the land management...

  1. Improvement of land information system of agricultural lands in Ukraine

    OpenAIRE

    A.S. Bordyuzha

    2014-01-01

    This paper deals with the nature of the state land cadastre, aspects of the land cadastral system functioning. Role of the land cadastre to create an effective agricultural land management system has been presented. Value of a land information system of the agricultural land in the management sphere and sustainable agricultural land use has been described.

  2. Land evaluation by the process of agricultural land consolidation - the case of land consolidation area Berkovci

    OpenAIRE

    Knavs, Alojz

    2008-01-01

    The thesis describes the course of procedure of agricultural land consolidation in Slovenia, based on valid legislation of land consolidation of agricultural land. The main stress is given on approaches to land evaluation of agricultural land consolidation fund, which is an important step at re-distribution of land from the land consolidation fund among the land owners. The main purpose of the thesis is to point out the importance of land evaluation by the process of land consolidation and to...

  3. Ecosystem restoration at the Arid-Semiarid Interface in Israel's Northern Negev

    Science.gov (United States)

    Mor-Mussery, Amir; Leu, Stefan; Bar-Kutiel, Pua

    2016-04-01

    The interface between the arid and semi-arid zones in Southern Israel (as elsewhere in the world) is heavily degraded. Thousands of years of overexploitation by wood cutting, farming and grazing have left the area at 10 - 30% of their nominal biological productivity, void of any trees and shrubs, and generally low in biodiversity. Degradation is an ongoing process in Israel's open areas, whereby overgrazing and continuous soil tilling for field crops, and contour trenching for planting of exotic tree species are the main drivers for ongoing soil degradation. The results of those activities are further loss of productivity, soil organic matter and soil nutrients, and massive soil erosion. In the framework of several research projects and a large ecosystem restoration project (http://www.sustainabilitylabs.org/ecosystem-restoration/) we have analyzed in detail the drivers of degradation by field studies accompanied by GIS analyses. Various approaches for soil restoration have been attempted and documented. Fencing of and protection from grazing has a rapid impact on the amount of standing biomass left both in rocky slopes, and degraded loess plains, leading to increased plant biodiversity, and initiating rapid growth in harvester ant activity. This ant activity seems to provide an important positive feedback on enhancing soil fertility and biological productivity, and we postulate a recovery mechanisms whereby enhanced food availability to ants and similar soil dwelling herbivores enhances soil nutrient pools, soil organic matter, soil aeration and soil water infiltration to result in a cycle of ongoing productivity improvements and ecosystem recovery. Alternative, faster and more expensive methods of restoration tested are overlaying of degraded soils using compost or manure, a method immediately restoring 5 - 10 fold higher biological productivity, which was being maintained for at least 10 years and appears permanent unless renewed degradation should occur. We

  4. 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

  5. Intervention Strategies to Improve Students¡¯ Academic Performance in Public Secondary Schools in Arid and Semi-Arid Lands in Kenya

    OpenAIRE

    Jacob Merew Katamei; Gedion A. Omwono

    2015-01-01

    Fullan (2007) defined school as a community of active people where teachers in a classroom environment convey formal education to learners. A school therefore facilitates education. Schools, whether government aided or private sponsored, have stakeholders who undertake various activities. In light of this, students¡¯ academic performance has been a key issue in education with many believing that the education programmes are not well interpreted in schools; thus resulting in poor academic perf...

  6. Analysis of aerosol-cloud-interactions over semi-arid and arid subtropical land regions from three different satellite datasets (MODIS, AATSR/ENVISAT, IASI)

    OpenAIRE

    Klüser, Lars

    2014-01-01

    Indirect aerosol effects, i.e. the change of cloud physical properties by aerosol interactions, have been identified as one of the largest uncertainties in the current understanding of the climate system. Despite the uncertainties of the representations of aerosol-cloud interactions in current climate projections, they have large impact on the climate system itself – in terms of the radiation balance, but also in terms of precipitation, and thus vegetation cover, and re-distribution of water ...

  7. Landing spot selection for UAV emergency landing

    NARCIS (Netherlands)

    Eendebak, P.T.; Eekeren, A.W.M. van; Hollander, R.J.M. den

    2013-01-01

    We present a robust method for landing zone selection using obstacle detection to be used for UAV emergency landings. The method is simple enough to allow real-time implementation on a UAV system. The method is able to detect objects in the presence of camera movement and motion parallax. Using the

  8. LandSat-Based Land Use-Land Cover (Vector)

    Data.gov (United States)

    Minnesota Department of Natural Resources — Vector-based land cover data set derived from classified 30 meter resolution Thematic Mapper satellite imagery. Classification is divided into 16 classes with...

  9. LandSat-Based Land Use-Land Cover (Raster)

    Data.gov (United States)

    Minnesota Department of Natural Resources — Raster-based land cover data set derived from 30 meter resolution Thematic Mapper satellite imagery. Classification is divided into 16 classes with source imagery...

  10. Sahra integrated modeling approach to address water resources management in semi-arid river basins

    Energy Technology Data Exchange (ETDEWEB)

    Springer, E. P.; Gupta, Hoshin V. (Hoshin Vijai),; Brookshire, David S.; Liu, Y. (Yuqiong)

    2004-01-01

    Water resources decisions in the 21Sf Century that will affect allocation of water for economic and environmental will rely on simulations from integrated models of river basins. These models will not only couple natural systems such as surface and ground waters, but will include economic components that can assist in model assessments of river basins and bring the social dimension to the decision process. The National Science Foundation Science and Technology Center for Sustainability of semi-Arid Hydrology and Riparian Areas (SAHRA) has been developing integrated models to assess impacts of climate variability and land use change on water resources in semi-arid river basins. The objectives of this paper are to describe the SAHRA integrated modeling approach and to describe the linkage between social and natural sciences in these models. Water resources issues that arise from climate variability or land use change may require different resolution models to answer different questions. For example, a question related to streamflow may not need a high-resolution model whereas a question concerning the source and nature of a pollutant will. SAHRA has taken a multiresolution approach to integrated model development because one cannot anticipate the questions in advance, and the computational and data resources may not always be available or needed for the issue to be addressed. The coarsest resolution model is based on dynamic simulation of subwatersheds or river reaches. This model resolution has the advantage of simplicity and social factors are readily incorporated. Users can readily take this model (and they have) and examine the effects of various management strategies such as increased cost of water. The medium resolution model is grid based and uses variable grid cells of 1-12 km. The surface hydrology is more physically based using basic equations for energy and water balance terms, and modules are being incorporated that will simulate engineering components

  11. Is aridity a high-order control on the hydro-geomorphic response of burned landscapes?

    Science.gov (United States)

    Sheridan, Gary; Van der Sant, Rene; Nyman, Petter; Lane, Patrick

    2015-04-01

    Fire results in hydro-geomorphic changes that are spatially variable and difficult to predict. In this study we compile 294 infiltration measurements, ten other soil, catchment runoff and erosion datasets, and a year of new data from 15 natural runoff plots across an aridity gradient from the eastern Victorian uplands in SE Australia. The results show that aridity (a function of the long term mean precipitation and net radiation) is associated with low post-fire infiltration capacities, increasing the chance of surface runoff, and strongly increasing the chance of debris flows. Runoff plots from the wettest site (aridity = 1.1) had an average runoff ratio of 0.3% compared with 33.6% for the most arid sites (aridity = 2.4). Post-fire debris flows were only observed in the more arid locations within the Victorian uplands, and resulted in erosion rates more than two orders of magnitude greater than non-debris flow processes. We therefore argue that in south eastern Australia aridity is a high-order control on the magnitude of post-wildfire hydro-geomorphic processes. The results from this Australian study may also help to provide insight into the landscape controls on post fire debris flows elsewhere. Aridity is a landscape-scale parameter that is mappable at a high resolution and therefore is a useful predictor of the spatial variability of the magnitude of post-fire hydro-geomorphic responses.

  12. 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

  13. 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

  14. 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

  15. 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

  16. Differences in the ARID-1 alpha expressions in squamous and adenosquamous carcinomas of uterine cervix.

    Science.gov (United States)

    Solakoglu Kahraman, Dudu; Diniz, Gulden; Sayhan, Sevil; Ayaz, Duygu; Uncel, Melek; Karadeniz, Tugba; Akman, Tulay; Ozdemir, Aykut

    2015-10-01

    AT-rich interactive domain 1A (ARID1A) is a tumor suppressor gene involved in chromatin remodeling which encodes ARID1A (BAF250a) protein. Recent studies have shown the loss of ARID1A expression in several types of tumors. This retrospective study was designed to evaluate the differences in tissue expressions of ARID1A in a spectrum of cervical neoplasms. Cervical intraepithelial neoplasms, invasive squamous or adenosquamous carcinomas were identified in 100 patients recently diagnosed as cervical neoplasms based on pathology databases. In this series, there were 29 low- and 29 high-grade cervical intraepithelial neoplasms, 27 squamous cell carcinomas, and 15 adenosquamous carcinomas. Mean age of the patients was 47.8 ± 13 years (20-80 years). It was determined that the expression of ARID1A was statistically significantly down-regulated in adenosquamous carcinomas when compared with non-invasive or invasive squamous cell carcinomas (p = 0.015). Lower levels of the ARID1A expression were detected in cases with adenosquamous carcinomas (60%), low- or high-grade squamous intraepithelial lesion (SIL) (31%), and squamous cell carcinomas (18.5%). Our findings have demonstrated the presence of a correlation between ARID1A expression and adenomatous differentiation of uterine squamous cell carcinomas. Therefore, ARID1A gene may suggestively have a role in the pathogenesis of cervical adenosquamous carcinomas.

  17. 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...

  18. Expansive Soil Properties in a Semi-Arid Region

    Directory of Open Access Journals (Sweden)

    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.

  19. Glacial aridity in central Indonesia coeval with intensified monsoon circulation

    Science.gov (United States)

    Konecky, Bronwen; Russell, James; Bijaksana, Satria

    2016-03-01

    The Last Glacial Maximum was cool and dry over the Indo-Pacific Warm Pool (IPWP), a key region driving global oceanic-atmospheric circulation. Both low- and high-latitude teleconnections with insolation, ice sheets, and sea level have been suggested to explain the pervasive aridity observed in paleoecological and geomorphic data. However, proxies tracking the H- and O-isotopic composition of rainfall (e.g., speleothems, sedimentary biomarkers) suggest muted aridity or even wetter conditions than the present, complicating interpretations of glacial IPWP climate. Here we use multiproxy reconstructions from lake sediments and modern rainfall isotopic measurements from central Indonesia to show that, contrary to the classical "amount effect," intensified Australian-Indonesian monsoon circulation drove lighter H- and O-isotopic composition of IPWP rainfall during the LGM, while at the same time, dry conditions prevailed. Precipitation isotopes are particularly sensitive to the apparent increase in monsoon circulation and perhaps also decreased moisture residence time implied by our data, explaining contrasts among proxy records while illuminating glacial IPWP atmospheric circulation, a key target for climate models.

  20. An Evaluation of Unsaturated Flow Models in an Arid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, J.

    1999-12-01

    The objective of this study was to evaluate the effectiveness of two unsaturated flow models in arid regions. The area selected for the study was the Area 5 Radioactive Waste Management Site (RWMS) at the Nevada Test Site in Nye County, Nevada. The two models selected for this evaluation were HYDRUS-1D [Simunek et al., 1998] and the SHAW model [Flerchinger and Saxton, 1989]. Approximately 5 years of soil-water and atmospheric data collected from an instrumented weighing lysimeter site near the RWMS were used for building the models with actual initial and boundary conditions representative of the site. Physical processes affecting the site and model performance were explored. Model performance was based on a detailed sensitivity analysis and ultimately on storage comparisons. During the process of developing descriptive model input, procedures for converting hydraulic parameters for each model were explored. In addition, the compilation of atmospheric data collected at the site became a useful tool for developing predictive functions for future studies. The final model results were used to evaluate the capacities of the HYDRUS and SHAW models for predicting soil-moisture movement and variable surface phenomena for bare soil conditions in the arid vadose zone. The development of calibrated models along with the atmospheric and soil data collected at the site provide useful information for predicting future site performance at the RWMS.

  1. 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.

  2. Soil microbial responses to nitrogen addition in arid ecosystems

    Directory of Open Access Journals (Sweden)

    Robert L Sinsabaugh

    2015-08-01

    Full Text Available The N cycle of arid ecosystems is influenced by low soil organic matter, high soil pH and extremes in water potential and temperature that lead to open canopies and development of biological soil crusts (biocrusts. We investigated the effects of N amendment on soil microbial dynamics in a Larrea tridentata-Ambrosia dumosa shrubland site in southern Nevada USA. Sites were fertilized with a NO3-NH4 mix at 0, 7, and 15 kg ha-1 yr-1 from March 2012 to March 2013. In March 2013, biocrust (0-0.5 cm and bulk soils (0-10 cm were collected beneath Ambrosia canopies and in the interspaces between plants. Biomass responses were assessed as bacterial and fungal SSU rRNA gene copy number and chlorophyll a concentration. Metabolic responses were measured by five ecoenzyme activities (EEA and rates of N transformation. By most measures, nutrient availability, microbial biomass and process rates were greater in soils beneath the shrub canopy compared to the interspace between plants, and greater in the surface biocrust horizon compared to the deeper 10 cm soil profile. Most measures responded positively to experimental N addition. Effect sizes were generally greater for bulk soil than biocrust. Results were incorporated into a meta-analysis of arid ecosystem responses to N.

  3. Resistance Status of the Malaria Vector Mosquitoes, Anopheles stephensi and Anopheles subpictus Towards Adulticides and Larvicides in Arid and Semi-Arid Areas of India

    OpenAIRE

    Tikar, S. N.; M J Mendki; Sharma, A K; D. Sukumaran; Veer, Vijay; Prakash, Shri; Parashar, B. D.

    2011-01-01

    Susceptibility studies of malaria vectors Anopheles stephensi Liston (Diptera: Culicidae) and An. subpictus Grassi collected during 2004–2007 from various locations of Arid and Semi-Arid Zone of India were conducted by adulticide bioassay of DDT, malathion, deltamethrin and larvicide bioassay of fenthion, temephos, chlorpyriphos and malathion using diagnostic doses. Both species from all locations exhibited variable resistance to DDT and malathion from majority of location. Adults of both the...

  4. Study on the oasis corridor landscape in the arid regions based on RS and GIS methods--application of Jinta Oasis, China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The study on the oasis corridor landscape is a new hotspot in the ecological environment research in the arid regions.In oasis, maincorridor landscape types include river, ditch, shelterbelt and road.This paper introduces the basic ecological effects of the corridor landscapeon the transporting mass and energy and obstructing desert landscape expansion and incursion.Using Geographic Information System(GIS), wehave researched the corridor distribution and its spatial relationship with other landscape types in the Jinta Oasis.Based on the dynamicallymonitoring on the landscape pattern change of the Jinta Oasis during the latter 10 years by using Remote Sensing(RS) and GIS, the drivingfunctions of the corridors on this change have been analyzed in detail.The analysis results showed that all kinds of corridors' characteristics canbe quantified by the indexes such as length and width, ratio of perimeter and area, density and non-heterogeneity.The total corridor length ofJinta Oasis is 1838.5 km and its density is 2.1 km/km2 .The corridor density of the irrigation land, forest and resident area is maximal, whichshows that affection degree of the oasis corridors on them is the most.The improvement of the corridors quality is one of the important drivingfactors on the irrigation land and so on.The organic combination of the RS and GIS technologies and landscape research methods would be aneffective means for the corridor landscape research on arid region oasis.

  5. Comparison of Land Skin Temperature from a Land Model, Remote Sensing, and In-situ Measurement

    Science.gov (United States)

    Wang, Aihui; Barlage, Michael; Zeng, Xubin; Draper, Clara Sophie

    2014-01-01

    Land skin temperature (Ts) is an important parameter in the energy exchange between the land surface and atmosphere. Here hourly Ts from the Community Land Model Version 4.0, MODIS satellite observations, and in-situ observations in 2003 were compared. Compared with the in-situ observations over four semi-arid stations, both MODIS and modeled Ts show negative biases, but MODIS shows an overall better performance. Global distribution of differences between MODIS and modeled Ts shows diurnal, seasonal, and spatial variations. Over sparsely vegetated areas, the model Ts is generally lower than the MODIS observed Ts during the daytime, while the situation is opposite at nighttime. The revision of roughness length for heat and the constraint of minimum friction velocity from Zeng et al. [2012] bring the modeled Ts closer to MODIS during the day, and have little effect on Ts at night. Five factors contributing to the Ts differences between the model and MODIS are identified, including the difficulty in properly accounting for cloud cover information at the appropriate temporal and spatial resolutions, and uncertainties in surface energy balance computation, atmospheric forcing data, surface emissivity, and MODIS Ts data. These findings have implications for the cross-evaluation of modeled and remotely sensed Ts, as well as the data assimilation of Ts observations into Earth system models.

  6. Impact of rhizobial populations and their host legumes on microbial activity in soils of arid regions in Tunisia

    International Nuclear Information System (INIS)

    Nitrogen fixing legumes and their microsymbionts are a fundamental contributor to soil fertility and prevent their degradation in arid and semi arid ecosystems. In Tunisia, few data are available on the contribution of these legumes in microbial activity in the arid soil. In this objective, a study was undertaken on five leguminous species from different arid regions to evaluate their ability to regenerate microbiological processes of the soil: Genista saharea, Genista microcephala, Acacia tortilis sspr raddiana, Retama raetam and Prosopis stephaniana. (Author)

  7. Impact of rhizobial populations and their host legumes on microbial activity in soils of arid regions in Tunisia

    Energy Technology Data Exchange (ETDEWEB)

    Fterich, A.; Mahdhi, M.; Mars, M.

    2009-07-01

    Nitrogen fixing legumes and their microsymbionts are a fundamental contributor to soil fertility and prevent their degradation in arid and semi arid ecosystems. In Tunisia, few data are available on the contribution of these legumes in microbial activity in the arid soil. In this objective, a study was undertaken on five leguminous species from different arid regions to evaluate their ability to regenerate microbiological processes of the soil: Genista saharea, Genista microcephala, Acacia tortilis sspr raddiana, Retama raetam and Prosopis stephaniana. (Author)

  8. Land Cover Characterization Program

    Science.gov (United States)

    ,

    1997-01-01

    The U.S. Geological Survey (USGS) has a long heritage of leadership and innovation in land use and land cover mapping. The USGS Anderson system defined the principles for land use and land cover mapping that have been the model both nationally and internationally for more than 20 years. The Land Cover Characterization Program (LCCP) is founded on the premise that the Nation's needs for land cover and land use data are diverse and increasingly sophisticated. The range of projects, programs, and organizations that use land cover data to meet their planning, management, development, and assessment objectives has expanded significantly. The reasons for this are numerous, and include the improved capabilities provided by geographic information systems, better and more data-intensive analytic models, and increasing requirements for improved information for decision making. The overall goals of the LCCP are to:

  9. The land management perspective

    DEFF Research Database (Denmark)

    Enemark, Stig

    2006-01-01

    Land management is the process by which the resources of land are put into good effect. Land management encompasses all activities associated with the management of land that are required to achieve sustainable development. The concept of land includes properties and natural resources and thereby...... encompasses the total natural and built environment. Land Administration Systems (LAS) are institutional frameworks complicated by the tasks they must perform, by national cultural, political and judicial settings, and by technology. This paper facilitates an overall understanding of the land management...... paradigm. In many countries, and especially developing countries and countries in transition, the national capacity to manage land rights, restrictions and responsibilities is not well developed in terms of mature institutions and the necessary human resources and skills. In this regard, the capacity...

  10. Focus on land reclamation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-04-01

    Various aspects of land reclamation, i.e. returning disturbed land to a state where, at minimum, it is at least capable of supporting the same kinds of land uses as before the disturbance, are discussed. Activities which disturb the land such as surface mining of coal, surface mining and extraction of oil sands, drilling for oil and natural gas, waste disposal sites, including sanitary landfills, clearing timber for forestry, excavating for pipelines and transportation are described, along with land reclamation legislation in Alberta, and indications of future developments in land reclamation research, legislation and regulation. Practical guidelines for individuals are provided on how they might contribute to land reclamation through judicious and informed consumerism, and through practicing good land management, inclusive of reduced use of herbicides, composting of household wastes, and planting of native species or ground cover in place of traditional lawns.

  11. US State Submerged Lands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Submerged Lands Act (43 U.S.C. Section 1301 et seq.) grants coastal states title to natural resources located within their coastal submerged lands and navigable...

  12. Initial land reclamation procedures related to possible Pu-cleanup activities at the Tonopah Test Range

    International Nuclear Information System (INIS)

    If areas of the Tonopah Test Range (TTR) are to be used for experimental tests of procedures for clean-up of 239Pu contamination, there are experiences in the Great Basin Desert portions of the Nevada Test Site (NTS) which can serve as guides to reclamation and revegetation of such arid lands. Procedures which will encourage development of the grasses Hilaria jamesii and Oryzopsis hymenoides, as well as the perennial shrubs Eurotia lanata and Atriplex canescens would greatly improve the area as range land

  13. Land Surface Processes Simulation Over Thar Desert in Northwest India

    Science.gov (United States)

    Raja, P.; Srinivas, C. V.; Hari Prasad, K. B. R. R.; Singh, Nilendu

    2016-06-01

    Land surface processes in data scarce arid northwestern India and their influence on the regional climate including monsoon are now gaining enhanced scientific attention. In this work the seasonal variation of land surface parameters and surface-energy flux components over Lasiurus sindicus grassland system in Thar Desert, western India were simulated using the mesoscale WRF model. The data on surface fluxes from a micrometeorological station, and basic surface level weather data from the Central Arid Zone Research Institute's experimental field station (26o59'41″N; 71o29'10″E), Jaisalmer, were used for comparison. Simulations were made for typical fair weather days in three seasons [12-14 January (peak winter); 29-31 May (peak summer), 19-21 August (monsoon)] during 2012. Sensitivity experiments conducted using a 5-layer soil thermal diffusion (5TD) scheme and a comprehensive land surface physics scheme (Noah) revealed the 5TD scheme gives large biases in surface fluxes and other land surface parameters. Simulations show large variations in surface fluxes and meteorological parameters in different seasons with high friction velocities, sensible heat fluxes, deep boundary layers in summer and monsoon season as compared to winter. The shortwave radiation is underestimated during the monsoon season, and is overestimated in winter and summer. In general, the model simulated a cold bias in soil temperature in summer and monsoon season and a warm bias in winter; the simulated surface fluxes and air temperature followed these trends. These biases could be due to a negative bias in net radiation resulting from a high bias in downward shortwave radiation in various seasons. The Noah LSM simulated various parameters more realistically in all seasons than the 5TD soil scheme due to inclusion of explicit vegetation processes in the former. The differences in the simulated fluxes with the two LSMs are small in winter and large in summer. The deep mixed layers are

  14. Biomarker evidence for increasing aridity in south-central India over the Holocene

    Science.gov (United States)

    Sarkar, S.; Wilkes, H.; Prasad, S.; Brauer, A.; Basavaiah, N.; Strecker, M. R.; Sachse, D.

    2012-12-01

    Summer monsoonal rainfall has played an important role in the development and sustenance of the largely agro-based economy in the Indian subcontinent in the recent past. A better understanding of past variations in monsoonal rainfall can therefore lead to an assessment of its potential impact on early human societies. However, our knowledge of spatiotemporal patterns of past monsoon strength, as inferred from proxy records, is limited due to the lack of high-resolution paleo-hydrological records from continental archives. Here, we reconstruct centennial-scale hydrological variability associated with changes in the intensity of the Indian Summer Monsoon based on a record of lipid biomarker abundances and compound-specific stable isotopic composition of a 10-m-long sediment core from saline-alkaline Lonar Lake, situated in the core 'monsoon zone' of south-central India. We identified three periods of distinct hydrology over the Holocene in south-central India. The period between 10.4 and 6.5 ka BP was characterized by a relatively high abundance of land-plant biomarkers, such as long-chain n-alkanes. The composition of these leaf-wax n-alkanes (weighted average of concentration of different chain-length n-alkanes, expressed as the ACL index) and their negative δ13C (-30‰ to -33 ‰) indicate the dominance of woody C3 vegetation in the catchment, and negative δD (-170‰ to -175‰) values argue for a wet period due to an intensified monsoon. Rapid fluctuations in abundance of both terrestrial and aquatic biomarkers between 6.5 and 4 ka BP indicate an unstable lake ecosystem, culminating in a transition to arid conditions. Higher ACL values and a pronounced shift to more positive δ13C values (up to -22‰) of leaf-wax n-alkanes over this period indicate a change of dominant vegetation to C4 grasses. Along with a 40‰ increase in leaf wax n-alkane δD values, which likely resulted from less rainfall and/or higher plant evapotranspiration, we interpret this period

  15. Apcocynum Pictum and Sustainable Agriculture Along the Tarim River In Arid Northwest, China

    Science.gov (United States)

    Aihemaitijiang, R.

    2014-12-01

    Water scarcity and population increase have been a major limiting factor in oasis development along the Tarim River in Xinjiang, Northwest China which has very continental and dry climate, and all the agriculture and livelihoods depend on glacier melt water from Tarim River. Due to vast land reclamation along the Tarim River to grow cotton, native plant species are facing a severe competition for water, which is essential for their survival. Decreasing river runoff and inefficient water use practices by agriculture and industry has exacerbated already serious situation even worse. In addition, a large influx of migrant famers from Eastern China is being settled in this region to cultivate new agricultural lands that consumed even more water. Under those conditions, the natural riparian vegetation and the irrigation agriculture, especially along the lower reaches, suffers water shortage leading the degradation and economic losses, respectively. Along with the enlargement of irrigation area and periods of water shortage, soil salinization has become a major concern for farmers in the area. Alternative cash crops are much needed to reduce water use, so both native vegetation and human demand for water would be fulfilled. We hypothesized Apocynum Pictum, perennial herb species with multiple uses as potential substitute. Multidisciplinary approach is being used in this study to investigate three related issues to offer a basis for Apocynum's role in sustainable agriculture, such as Biomass production of Apocynum; Water budget of Apocynum; and Economic utilization of Apocynum. A.Pictum is perennial plant distributed in Central Asia and China, which its roots are perennial, while the stems die every year. Thus, A.pictum grow under the arid climate of Central Asia and provide utilization options without irrigation. We initially estimate water requirement for this plant is much less than cotton. In order to validate our hypothesis, we have measured water consumption of the

  16. Protecting Land and Resources

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    LAND is a resource vital to life and production. China Today recently visited Wang Dacao, head of the Liaoning Provincial Department of Land and Resources. We asked him how the province protects and utilizes its land and resources for the purposes of sustainable development and benefit of later generations.Rich ResourcesThe land and sea within the boundaries of Liaoning Province, northeastern China

  17. Land Officials' Views

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Wang Songlin (Director of the Zhejiang Provincial Department of Land and Resources): The per-capita land of Zhejiang is only 0.033 hectares, with few backup resources. Thus, we are faced with more difficulties and pressure with regard to cultivated land conservation. Zhejiang is taking the following measures to protect cultivated land: First, we will create more standard farmland. The provincial government is

  18. Land Reform and Sustainable Development

    OpenAIRE

    Elizabeth Stanton; Peter Rosset; James Boyce

    2005-01-01

    Land reform, equitable distribution, economic development, environmental quality, land reform strategies, Brazil, Landless Workers’ Movement, East Asia, rural poverty, land productivity, sustainable agriculture, comparative advantage, small farms.

  19. Analyses of environmental impacts of underground coal mining in an arid region using remote sensing and GIS

    Institute of Scientific and Technical Information of China (English)

    BIAN Zheng-fu; ZHANG Hai-xia; LEI Shao-gang

    2011-01-01

    The influences of coal mining in an arid environment on vegetation coverage,land-use change,desertification,soil and water loss were discussed.A series of available TM/ETM+ images with no cloud cover from July/August in different years (1990,1995,2000 and 2005)were used to analyze the change in various land environmental factors over time.The results show that while mining activity initially had a marked adverse impact on the environment,mine rehabilitation measures have also subsequently played a great role in improving vegetation cover and controlling land desertification and loss of water and soil.The effect of coal mining on vegetation cover is dependent upon the soil type and natural indigenous flora.Results of this investigation imply that mining activity has a greater effect on the vegetation of loess areas than at sandy sites.Although local vegetation coverage was improved by planting in the mining area,the total area of land affected by desertification still increased from 26.81% in 1990 when large-scale mine construction was introduced,to 46.79% in 1995.With continuous efforts at rehabilitation,the vegetation cover in the Shendong coal mining area was increasing,and loss of water and soil were effectively controlled since 1995.Subsequently,the total area of extreme desertification decreased to 23.24% in 2000 and further to 18.68% in 2005.The total area affected by severe loss of water and soil also decreased since the early 1990's(70.61% in 1990,71.43% in 1995),to 43.64% in 2000 and 34.93% in 2005,respectively.

  20. Understanding land administration systems

    DEFF Research Database (Denmark)

    P. Williamson, Ian; Enemark, Stig; Wallace, Judy;

    2008-01-01

    This paper introduces basic land administration theory and highlights four key concepts that are fundamental to understanding modern land administration systems. Readers may recall the first part of the paper in October issue of Coordinates. Here is the concluding part that focuses on the changing...... role of ownership and the role of land markets. Udgivelsesdato: November...

  1. Tough Land Guardian

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    One of the most controversial issues facing Chinese society is the illegal expropriation of farm-land. New head of the Ministry of Land and Resources, China’s top land watchdog, Xu Shaoshi, has taken a tough stance on this issue stepping into his positio

  2. 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.

  3. Rainfall-runoff relationship of some catchments with karstic geomorphology under arid to semi-arid conditions

    Science.gov (United States)

    De Vera, Maximo R.

    1984-02-01

    The relationship between rainfall and runoff of fourteen catchments with a total area of 5983 km 2 in the northeastern zone of Libya was reviewed in an attempt to determine the effect of karstic geomorphology on the runoff coefficient. Available data since 1965 were collated and eight wadis with at least eleven flood events were used for linear regression analysis. The selected catchments are under arid to semi-arid conditions with mean annual rainfall of 50-500 mm and with surface geology consisting mostly of marly limestone which is favourable to karstification phenomena. The ratio of runoff to rainfall is extremely variable with a range of 0.0001-0.830, and therefore it is not a reliable criterion for runoff estimation, especially with the limited data subjected to statistical analysis. The regression analysis shows correlation coefficients from 0.219 to 0.89 with no apparent effect of size of catchment area. As indicated by the coefficient of determination, 4.8-80.3% of the variation in runoff has been accounted for by the regression. The extent and degree of karstification, if properly quantified, can be a significant factor for runoff prediction, in addition to rainfall intensity and duration, antecedent soil moisture, effective catchment area and other geomorphological features.

  4. Trend in land degradation has been the most contended issue in the Sahel. Trends documented have not been consistent across authors and science disciplines, hence little agreement has been gained on the magnitude and direction of land degradation in the Sahel. Differentiated science outputs are related to methods and data used at various scales.

    Science.gov (United States)

    Mbow, C.; Brandt, M.; Fensholt, R.; Ouedraogo, I.; Tagesson, T.

    2015-12-01

    Thematic gaps in land degradation trends in the SahelTrend in land degradation has been the most contended issue for arid and semi-arid regions. In the Sahel, depending to scale of analysis and methods and data used, the trend documented have not been consistent across authors and science disciplines. The assessment of land degradation and the quantification of its effects on land productivity have been assessed for many decades, but little agreement has been gained on the magnitude and direction in the Sahel. This lack of consistency amid science outputs can be related to many methodological underpinnings and data used for various scales of analysis. Assessing biophysical trends on the ground requires long-term ground-based data collection to evaluate and better understand the mechanisms behind land dynamics. The Sahel is seen as greening by many authors? Is that greening geographically consistent? These questions enquire the importance of scale analysis and related drivers. The questions addressed are not only factors explaining loss of tree cover but also regeneration of degraded land. The picture used is the heuristic cycle model to assess loss and damages vs gain and improvements of various land use practices. The presentation will address the following aspects - How much we know from satellite data after 40 years of remote sensing analysis over the Sahel? That section discuss agreement and divergences of evidences and differentiated interpretation of land degradation in the Sahel. - The biophysical factors that are relevant for tracking land degradation in the Sahel. Aspects such detangling human to climate factors and biophysical factors behind land dynamics will be presented - Introduce some specific cases of driver of land architecture transition under the combined influence of climate and human factor. - Based on the above we will conclude with some key recommendations on how to improve land degradation assessment in the Arid region of the Sahel.

  5. A global dataset of the extent of irrigated land from 1900 to 2005

    Directory of Open Access Journals (Sweden)

    S. Siebert

    2014-12-01

    Full Text Available Irrigation intensifies land use by increasing crop yield but also impacts water resources. It affects water and energy balances and consequently the microclimate in irrigated regions. Therefore, knowledge of the extent of irrigated land is important for hydrological and crop modelling, global change research, and assessments of resource use and management. Information on the historical evolution of irrigated lands is limited. The new global Historical Irrigation Dataset (HID provides estimates of the temporal development of the area equipped for irrigation (AEI between 1900 and 2005 at 5 arc-minute resolution. We collected subnational irrigation statistics from various sources and found that the global extent of AEI increased from 63 million ha (Mha in 1900 to 112 Mha in 1950 and 306 Mha in 2005. We developed eight gridded versions of time series of AEI by combining subnational irrigation statistics with different data sets on the historical extent of cropland and pasture. Different rules were applied to maximize consistency of the gridded products to subnational irrigation statistics or to historical cropland and pasture data sets. The HID reflects very well the spatial patterns of irrigated land in the western United States as shown on historical maps. Mean aridity on irrigated land increased and river discharge decreased from 1900–1950 whereas aridity decreased from 1950–2005. The dataset and its documentation are made available in an open data repository at https://mygeohub.org/publications/8 (doi:10.13019/M2MW2G.

  6. Energy Partition From Various Climate Conditions And Land Use Types

    Science.gov (United States)

    Cheng, Chi-Han; Hsu2, Pang-Chi

    2015-04-01

    Investigating how energy partitions and what factors control energy exchange is critical for better understanding the hydrological cycle, boundary layer dynamics, and land -atmosphere coupling. Climate and land use conditions are the two main factors to control energy partitation. However, previous studies discussed energy partition and factors that controlled Bowen ratio (i.e., ratio of sensible heat flux to latent heat flux) in limited land use types and climate conditions. To provide a more comprehensive analysis over various climate and vegetation types, in this study, we studied eleven different land use types in the eight different climate zones within the United State. The results found out that the Mediterranean climate zone with dry summer season, dry arid (desert) climate zone, and the higher latitude area with severe winter would had higher Bowen ratio, lower precipitation and net radiation. In contrast, the humid climate zones had the lower Bowen ratio, higher net radiation and precipitation. Moreover, the higher Bowen ratio usually happened in the winter or early spring seasons. Regarding land conditions, it is found that soil moistures are the key factor to control Bowen ratio in the drier climate areas. Hence, the grassland and closed shrublands sites have higher Bowen ratio than deciduous broadleaf forests and evergreen needle-leaf forests sites' because of shallower root systems that lack access to the full storage of water in the vadose zone. However, in the humid areas, land use factors, such as stomatal resistance and leaf area, would play an important role in changing latent heat and sensible heat. Based on the tight relationships between Bowen ratio and conditions of climate and land use, we suggest that Bowen ratio could be a useful tool for understanding the potential feedbacks of changes in climate and land use to energy partition and exchange.

  7. Modelling land use change in the Ganga basin

    Science.gov (United States)

    Moulds, Simon; Mijic, Ana; Buytaert, Wouter

    2014-05-01

    Over recent decades the green revolution in India has driven substantial environmental change. Modelling experiments have identified northern India as a "hot spot" of land-atmosphere coupling strength during the boreal summer. However, there is a wide range of sensitivity of atmospheric variables to soil moisture between individual climate models. The lack of a comprehensive land use change dataset to force climate models has been identified as a major contributor to model uncertainty. This work aims to construct a monthly time series dataset of land use change for the period 1966 to 2007 for northern India to improve the quantification of regional hydrometeorological feedbacks. The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on board the Aqua and Terra satellites provides near-continuous remotely sensed datasets from 2000 to the present day. However, the quality and availability of satellite products before 2000 is poor. To complete the dataset MODIS images are extrapolated back in time using the Conversion of Land Use and its Effects at Small regional extent (CLUE-S) modelling framework, recoded in the R programming language to overcome limitations of the original interface. Non-spatial estimates of land use area published by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) for the study period, available on an annual, district-wise basis, are used as a direct model input. Land use change is allocated spatially as a function of biophysical and socioeconomic drivers identified using logistic regression. The dataset will provide an essential input to a high-resolution, physically-based land-surface model to generate the lower boundary condition to assess the impact of land use change on regional climate.

  8. Water pulses and biogeochemical cycles in arid and semiarid ecosystems.

    Science.gov (United States)

    Austin, Amy T; Yahdjian, Laura; Stark, John M; Belnap, Jayne; Porporato, Amilcare; Norton, Urszula; Ravetta, Damián A; Schaeffer, Sean M

    2004-10-01

    The episodic nature of water availability in arid and semiarid ecosystems has significant consequences on belowground carbon and nutrient cycling. Pulsed water events directly control belowground processes through soil wet-dry cycles. Rapid soil microbial response to incident moisture availability often results in almost instantaneous C and N mineralization, followed by shifts in C/N of microbially available substrate, and an offset in the balance between nutrient immobilization and mineralization. Nitrogen inputs from biological soil crusts are also highly sensitive to pulsed rain events, and nitrogen losses, particularly gaseous losses due to denitrification and nitrate leaching, are tightly linked to pulses of water availability. The magnitude of the effect of water pulses on carbon and nutrient pools, however, depends on the distribution of resource availability and soil organisms, both of which are strongly affected by the spatial and temporal heterogeneity of vegetation cover, topographic position and soil texture. The 'inverse texture hypothesis' for net primary production in water-limited ecosystems suggests that coarse-textured soils have higher NPP than fine-textured soils in very arid zones due to reduced evaporative losses, while NPP is greater in fine-textured soils in higher rainfall ecosystems due to increased water-holding capacity. With respect to belowground processes, fine-textured soils tend to have higher water-holding capacity and labile C and N pools than coarse-textured soils, and often show a much greater flush of N mineralization. The result of the interaction of texture and pulsed rainfall events suggests a corollary hypothesis for nutrient turnover in arid and semiarid ecosystems with a linear increase of N mineralization in coarse-textured soils, but a saturating response for fine-textured soils due to the importance of soil C and N pools. Seasonal distribution of water pulses can lead to the accumulation of mineral N in the dry season

  9. Landing gear noise attenuation

    Science.gov (United States)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  10. Land Treatment Digital Library

    Science.gov (United States)

    Pilliod, David S.; Welty, Justin L.

    2013-01-01

    The Land Treatment Digital Library (LTDL) was created by the U.S. Geological Survey to catalog legacy land treatment information on Bureau of Land Management lands in the western United States. The LTDL can be used by federal managers and scientists for compiling information for data-calls, producing maps, generating reports, and conducting analyses at varying spatial and temporal scales. The LTDL currently houses thousands of treatments from BLM lands across 10 states. Users can browse a map to find information on individual treatments, perform more complex queries to identify a set of treatments, and view graphs of treatment summary statistics.

  11. Land desertification and restoration in Middle East and North Africa (MENA) region

    Institute of Scientific and Technical Information of China (English)

    Hassan M.El Shaer

    2015-01-01

    The Middle East and North Africa (MENA) region is characterized by high population growth, degraded and fragile nat-ural ecosystems, and a limited amount of arable lands. It is one of the most water-scarce regions in the world. The region is heterogeneous in terms of the countries' economies, but because it includes some of the richest and some of the poorest countries in the world, regional average economic performance statistics are misleading. The region is mostly semi-arid and arid, with significant areas of extreme aridity. These areas are further challenged by extreme temperatures, frequent drought, land degradation, and desertification. Recent changes in climate patterns, such as prolonged droughts, record temperatures, and increased rainfall irregularity, intensity and distribution, have all further negatively impacted the natural and agro-ecosystems in the region. Such changes have led to increased vulnerability of the people dependent on such re-sources for their livelihood. This article focuses on the impact of land desertification due to climate changes on the pre-vailing natural resources, and discusses several approaches for mitigating or alleviating desertification. It is clear that water shortage is a problem in many countries of this predominantly arid region, and is unlikely to be reduced and may be exacerbated by climate change. Proposed adaptation strategies might include more efficient organization of water supplies, treatment, and delivery systems, and increased use of groundwater. It is necessary to develop alternative production and management systems appropriate to the socioeconomic and environmental conditions in order to prevent further degradation of the prevailing agro-ecosystems and sustain the livelihoods of farmers living in marginal conditions. Grasslands, livestock, and water resources are likely to be most vulnerable to climate change in the region because they are located mostly in marginal areas. Changes in cropping practices

  12. International Coalition Land Use/Land Cover

    Data.gov (United States)

    Minnesota Department of Natural Resources — This data set is a product of an effort to update Minnesota's 1969 land use inventory. The project was funded in 1989 by the State Legislature per recommendation...

  13. Bureau of Land Management Land Grant Boundaries

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This data has been collected by the U.S. Bureau of Land Management (BLM) in New Mexico at the New Mexico State Office. The initial data source is the statewide...

  14. Applications of Soil Series in Sustainable Land Use of Oasis Farmlands

    Institute of Scientific and Technical Information of China (English)

    QI Shan-zhong; XIAO Hong-lang; LUO Fang

    2005-01-01

    The issue of agricultural land sustainability is important to every part of the world, especially in the developing countries. Based on the data collected by field investigation and laboratory analysis as well as soil classification theory, the authors discuss the applications of soil series in the arid northwestern China. On the one hand, the application in the layout of rational agricultural of oasis farmlands: (1) two soil series,namely,Lanjiabao (main) and Nijiaxiaying, belong to the moderate and extremely arid region in the study area; accordingly, the layout of crops is the spring wheat and maize (main) and winter wheat;(2) Nijiaxiaying (main) and Lanjiabao, however, fall into the warm-cold and extremely arid region, where the winter wheat (main) and spring wheat grow; and (3) the Shangfusi is part of the warm chilly-arid region, which is used as seasonal pastureland. On the other hand, the application on the soil quality of oasis farmlands, the results indicating that among all soil series, the content of N is very low, however, the content of K is abundant, and the content of P is greatly scarce.

  15. Impact of Direct Soil Moisture and Revised Soil Moisture Index Methods on Hydrologic Predictions in an Arid Climate

    Directory of Open Access Journals (Sweden)

    Milad Jajarmizadeh

    2014-01-01

    Full Text Available The soil and water assessment tool (SWAT is a physically based model that is used extensively to simulate hydrologic processes in a wide range of climates around the world. SWAT uses spatial hydrometeorological data to simulate runoff through the computation of a retention curve number. The objective of the present study was to compare the performance of two approaches used for the calculation of curve numbers in SWAT, that is, the Revised Soil Moisture Index (SMI, which is based on previous meteorological conditions, and the Soil Moisture Condition II (SMCII, which is based on soil features for the prediction of flow. The results showed that the sensitive parameters for the SMI method are land-use and land-cover features. However, for the SMCII method, the soil and the channel are the sensitive parameters. The performances of the SMI and SMCII methods were analyzed using various indices. We concluded that the fair performance of the SMI method in an arid region may be due to the inherent characteristics of the method since it relies mostly on previous meteorological conditions and does not account for the soil features of the catchment.

  16. Effect of climate change on the vulnerability of a socio-ecological system in an arid area

    Science.gov (United States)

    Liu, Hai-Long; Willems, Patrick; Bao, An-Ming; Wang, Ling; Chen, Xi

    2016-02-01

    The vulnerability of arid areas threatens ecosystems and human existence. With climate change and increasing human activities, addressing this vulnerability has become an important concern. To support this objective, we present a complex index system to analyze vulnerability at a regional scale with a 1 km × 1 km resolution. Based on the evaluation framework, which includes natural resources, the natural environment and the social economy, the results indicate that an ecosystem in a mountainous area is more vulnerable than it is in a plain. Land desertification will worsen from 2014 to 2099 under the RCP4.5 scenarios and improve slightly under the RCP8.5 and RCP2.6 scenarios, while the suitable land for agriculture increased slightly under the three scenarios. In addition, a regional sensitivity analysis of vulnerability to climate change shows that the improving region and the worsening region will occupy 1.30% and 74.51%, respectively. In view of this, the socio-ecological system will undergo a worsening trend as a whole. Finally, we simplified how to solve the problem of a socio-ecological system in the future. This research method and results would generate new insights with respect to planning for sustainable development and provide a reference for decision-making.

  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 novel approach in estimating surface energy balance: new perspective of urban-rural contrast in arid cities

    Science.gov (United States)

    Wang, Z.; Yang, J.

    2015-12-01

    Hydrological and thermal processes over the earth's surface are essentially coupled and driven by the partitioning of available energy. The evolution of surface temperature implicitly contains the signature of energy partitioning that it can be used to diagnose the surface energy balance. Compared to land surface, energy partitioning over water surface is further complicated by the penetration and absorption of solar radiation in the water body. In this study, we developed a novel analytical method for the reconstruction of surface temperature and for the estimation of all surface energy components, by combining Green's function approach and linear stability analysis. This new method only requires one single depth measurement of temperature or flux, and applies to the surface energy balance over either land (soil) or water continuum. Model assessment was made against in-situ measurements and numerical predications of the maximum entropy production method, indicating that this approach is robust and of good accuracy. The understanding of the surface energy balance, enabled by this new approach, has been applied to an arid city, viz. Phoenix AZ, to reveal new perspectives of different urban-rural contrasts in terms of thermal and hydrological processes.

  19. Land reclamation in Egypt

    DEFF Research Database (Denmark)

    Adriansen, Hanne Kirstine

    2009-01-01

    For decades, Egypt has tried to increase its agricultural area through reclamation of desert land. The significance of land reclamation goes beyond the size of the reclaimed area and number of new settlers and has been important to Egyptian agricultural policies since the 1952-revolution. This pa......For decades, Egypt has tried to increase its agricultural area through reclamation of desert land. The significance of land reclamation goes beyond the size of the reclaimed area and number of new settlers and has been important to Egyptian agricultural policies since the 1952-revolution...... villages, and lack of good schools and other public services may cause families to split up. For some, however, resettlement in the new lands entails new social and economic possibilities. The paper concludes that while land reclamation may not be ecologically or economic sustainable, the new lands provide...

  20. Sensing land pollution.

    Science.gov (United States)

    Bowden, L. W.

    1971-01-01

    Land pollution is described in numerous ways by various societies. Pollutants of land are material by-products of human activity and range from environmentally ineffective to positively toxic. The pollution of land by man is centuries old and correlates directly with economy, technology and population. In order to remotely sense land pollution, standards or thresholds must be established. Examples of the potential for sensing land pollution and quality are presented. The technological capabilities for remotely sensed land quality is far advanced over the judgment on how to use the sensed data. Until authoritative and directive decisions on land pollution policy are made, sensing of pollutants will be a random, local and academic affair.