WorldWideScience

Sample records for agroecosystems

  1. Agroecosystem Impacts on Water Quality

    Science.gov (United States)

    Reedy, R. C.; Scanlon, B. R.

    2010-12-01

    Agroecosystems can have large scale impacts on soil water and groundwater quality by mobilizing salts into underlying aquifers through enhanced recharge and increasing chemical loading to systems through fertilizer applications and irrigation water. Crop evapotranspiration is similar to desalinization in that root-water uptake excludes most salts, and soil-water salinity levels may build up when water drainage or percolation through the root zone is insufficient to flush accumulated salts. The objective of this study was to evaluate impacts of agroecosystems on soil water and groundwater quality using data from the US High Plains and California Central Valley. Natural ecosystems accumulated large reservoirs of salts in unsaturated soils in the southern High Plains and southern part of the Central Valley. Increased recharge under rainfed and irrigated agriculture mobilized these salt reservoirs into the underlying aquifer in the southern High Plains, increasing groundwater salinity, particularly chloride and sulfate. Deficit irrigation in the southern High Plains has created large salt bulges in the unsaturated zone because of insufficient irrigation to flush these salts into the underlying aquifer. Irrigation in both the High Plains and Central Valley regions has markedly increased groundwater nitrate levels, particularly in irrigated areas because of higher fertilizer applications. Agroecosystem impacts on water quality reflect a delicate balance between water and salt cycles and crop production should be managed to minimize negative environmental impacts.

  2. The circulation physiology of agroecosystems

    Institute of Scientific and Technical Information of China (English)

    Cao Zhiping; Richard Dawson

    2007-01-01

    This paper represents an effort to enlarge the understanding of the biophysical foundation of agroecosystems by using an analogy with the circulation of the blood in the human body. The circulation function in the human body can be represented as arterial pressure. The factors affecting arterial pressure in the human body have direct counterparts in the cultivation-husbandry system. The relationship between circulation pressure and the factors affecting that pressure in the cultivation-husbandry system are similar to the relationship between the arterial pressure and factors affecting arterial pressure in the human body. Furthermore, circulation resistance in the cultivation-husbandry system can be shown to be analogous to the calculation of peripheral resistance in the human body by Poiseuille's formula.

  3. Ecohydrological modeling in agroecosystems: Examples and challenges

    Science.gov (United States)

    Porporato, A.; Feng, X.; Manzoni, S.; Mau, Y.; Parolari, A. J.; Vico, G.

    2015-07-01

    Human societies are increasingly altering the water and biogeochemical cycles to both improve ecosystem productivity and reduce risks associated with the unpredictable variability of climatic drivers. These alterations, however, often cause large negative environmental consequences, raising the question as to how societies can ensure a sustainable use of natural resources for the future. Here we discuss how ecohydrological modeling may address these broad questions with special attention to agroecosystems. The challenges related to modeling the two-way interaction between society and environment are illustrated by means of a dynamical model in which soil and water quality supports the growth of human society but is also degraded by excessive pressure, leading to critical transitions and sustained societal growth-collapse cycles. We then focus on the coupled dynamics of soil water and solutes (nutrients or contaminants), emphasizing the modeling challenges, presented by the strong nonlinearities in the soil and plant system and the unpredictable hydroclimatic forcing, that need to be overcome to quantitatively analyze problems of soil water sustainability in both natural and agricultural ecosystems. We discuss applications of this framework to problems of irrigation, soil salinization, and fertilization and emphasize how optimal solutions for large-scale, long-term planning of soil and water resources in agroecosystems under uncertainty could be provided by methods from stochastic control, informed by physically and mathematically sound descriptions of ecohydrological and biogeochemical interactions.

  4. [Advances in energy analysis of agro-ecosystems].

    Science.gov (United States)

    Lu, Hongfang; Lan, Shengfang; Chen, Feipeng; Peng, Shaolin

    2004-01-01

    The energy analysis of agro-ecosystems from the view point of energy flow is a quantitative study on the function of agro-ecosystem, and is one of the most important aspects in agro-ecosystem study. In this paper, the history and some current progresses of energy analysis on agro-ecosystems were reviewed briefly, and the difference and breakthrough of emergy analysis theory with the traditional energy analysis method, some current challenges in front of emergy analysis of agro-ecosystems, and some of the new trends were discussed. Using the direct and indirect cost of solar energy to evaluate any energy or material, emergy analysis is the new development of energy analysis, not only in concept but also on calculation method. Developing to emergy analysis phase, there were still some deficiencies on energy analysis of agro-ecosystem, such as the complicate calculation of transformation and the vacancy of energy index for sustainable development, etc. How to solve these problems combined with the clearing of the maximum Em-power principle, the combination among energy analysis, emergy analysis, material analysis and landscape analysis has made up of the current and future trends of energy analysis of agro-ecosystem.

  5. Antibiotics and antibiotic resistance in agroecosystems: State of the science

    Science.gov (United States)

    This review article proposes a simple causal model depicting relationships involved in dissemination of antibiotics and antibiotic resistance in agroecosystems and potential effects on human health, functioning of natural ecosystems, and agricultural productivity. Available evidence for each causal ...

  6. Nutrient disequilibria in agroecosystems: concepts and case studies

    NARCIS (Netherlands)

    Smaling, E.M.A.; Oenema, O.; Fresco, L.O.

    1999-01-01

    The stocks and flows of carbon and nutrients in the terrestrial and marine agroecosystems within the environment are discussed, and the latest concepts on the causes of nutrient imbalances are considered. Case studies are presented.

  7. Assessment of federal databases to evaluate agroecosystem productivity

    Energy Technology Data Exchange (ETDEWEB)

    Olson, G.L.; Breckenridge, R.P.; Wiersma, G.B.

    1990-02-01

    Ecological monitoring data that could provide indications of agroecosystem condition, such as soil microbial biomass, biodiversity in the patches or mineralizable-N, are not available on a national scale. This paper discusses the economists' and ecologists' approach to assessing agroecosystem productivity, and the data available to make ecological assessments of agroecosystems on a national level. Models and indices of productivity used by ecologists and economists are briefly discussed in the context of agricultural inputs and outputs. Databases on production, pesticides, fertilizers, water use, water and air quality, land use, soil, labor and machinery are evaluated for their ability to make national trend assessments on how this ecosystem responds to stress. 39 refs., 3 figs., 3 tabs.

  8. The role of arable weed seeds for agroecosystem functioning

    NARCIS (Netherlands)

    Franke, A.C.; Lotz, L.A.P.; Burg, van der W.J.; Overbeek, van L.S.

    2009-01-01

    A literature study was conducted to gather knowledge on the impact of weed seeds on agroecosystem functioning other than effects related to the production of weed seedlings and plants. The results of the review suggested that a larger and more diverse weed seedbank can contribute to the biodiversity

  9. Antibiotics in agroecosystems: Introduction to the special section

    Science.gov (United States)

    The presence of antibiotic drug residues, antibiotic resistant bacteria, and antibiotic resistance genes in agroecosystems has become a significant area of research in recent years, and is a growing public health concern. While antibiotics are utilized for human medicine and agricultural practices, ...

  10. Comparing Energy Use and Efficiency in Central Iowa Agroecosystems

    Science.gov (United States)

    Cox, Rachael; Wiedenhoeft, Mary

    2009-01-01

    Energy is relevant to all areas of human life; energy sustains us through food, drives our transportation, warms and cools our buildings, and powers our electrical gadgets. In nature, ecosystems function by capturing and transforming energy. Agroecosystems are formed when humans manipulate the capture and flow of energy for food, fiber, and fuel…

  11. Assessing and monitoring impacts of genetically modified plants on agro-ecosystems

    DEFF Research Database (Denmark)

    Arpaia, S.; Messéan, A.; Birch, N.A.;

    2014-01-01

    -funded research project AMIGA − Assessing and monitoring Impacts of Genetically modified plants on Agro-ecosystems − aims to address this issue, by providing a framework that establishes protection goals and baselines for European agro-ecosystems, improves knowledge on the potential long term environmental...... focuses on ecological studies in different EU regions, the sustainability of GM crops is estimated by analysing the functional components of the agro-ecosystems and specific experimental protocols are being developed for this scope....

  12. Ecological Sustainability of a Wheat-cotton Agroecosystem in Khorassan

    Directory of Open Access Journals (Sweden)

    abdolmajid mahdavi damghani

    2009-06-01

    Full Text Available In order to develop a sustainability index (SI for quantifying the sustainability of a wheat-cotton agroecosystem, a study was conducted in 2003 in the Khorassan province. Data of socio-economic, agronomic and ecological indicators were collected using 518 questionnaires. Results showed that only 18.6 percent of farmers gained the half or more of SI scores. The mean SI score was 44.0 which indicate that these agroecosystems are not sustainable. Results of this study are in consistent with other reports in other regions of the country. Livestock production, crop production, and water and irrigation indicators had the lowest score (6, 31, and 37, respectively. The backward stepwise regression analysis indicated that SI can be predicted from a linear combination of field size, wheat yield, crop residue management, crop income and education and extension services, while application of chemical fertilizers did not add to the prediction ability of SI. Results also showed that any progress in farmers’ education, economic viability, crop production management and water use efficiency could improve overall sustainability of these agroecosystems substantially.

  13. Trace elements in agroecosystems and impacts on the environment.

    Science.gov (United States)

    He, Zhenli L; Yang, Xiaoe E; Stoffella, Peter J

    2005-01-01

    Trace elements mean elements present at low concentrations (mg kg-1 or less) in agroecosystems. Some trace elements, including copper (Cu), zinc (Zn), manganese (Mn), iron (Fe), molybdenum (Mo), and boron (B) are essential to plant growth and are called micronutrients. Except for B, these elements are also heavy metals, and are toxic to plants at high concentrations. Some trace elements, such as cobalt (Co) and selenium (Se), are not essential to plant growth but are required by animals and human beings. Other trace elements such as cadmium (Cd), lead (Pb), chromium (Cr), nickel (Ni), mercury (Hg), and arsenic (As) have toxic effects on living organisms and are often considered as contaminants. Trace elements in an agroecosystem are either inherited from soil parent materials or inputs through human activities. Soil contamination with heavy metals and toxic elements due to parent materials or point sources often occurs in a limited area and is easy to identify. Repeated use of metal-enriched chemicals, fertilizers, and organic amendments such as sewage sludge as well as wastewater may cause contamination at a large scale. A good example is the increased concentration of Cu and Zn in soils under long-term production of citrus and other fruit crops. Many chemical processes are involved in the transformation of trace elements in soils, but precipitation-dissolution, adsorption-desorption, and complexation are the most important processes controlling bioavailability and mobility of trace elements in soils. Both deficiency and toxicity of trace elements occur in agroecosystems. Application of trace elements in fertilizers is effective in correcting micronutrient deficiencies for crop production, whereas remediation of soils contaminated with metals is still costly and difficult although phytoremediation appears promising as a cost-effective approach. Soil microorganisms are the first living organisms subjected to the impacts of metal contamination. Being responsive and

  14. Meteorological risks as drivers of innovation for agroecosystem management

    Science.gov (United States)

    Gobin, Anne; Van de Vyver, Hans; Zamani, Sepideh; Curnel, Yannick; Planchon, Viviane; Verspecht, Ann; Van Huylenbroeck, Guido

    2015-04-01

    Devastating weather-related events recorded in recent years have captured the interest of the general public in Belgium. The MERINOVA project research hypothesis is that meteorological risks act as drivers of environmental innovation in agro-ecosystem management which is being tested using a "chain of risk" approach. The major objectives are to (1) assess the probability of extreme meteorological events by means of probability density functions; (2) analyse the extreme events impact of on agro-ecosystems using process-based bio-physical modelling methods; (3) identify the most vulnerable agro-ecosystems using fuzzy multi-criteria and spatial analysis; (4) uncover innovative risk management and adaptation options using actor-network theory and economic modelling; and, (5) communicate to research, policy and practitioner communities using web-based techniques. Generalized Extreme Value (GEV) theory was used to model annual rainfall maxima based on location-, scale- and shape-parameters that determine the centre of the distribution, the deviation of the location-parameter and the upper tail decay, respectively. Likewise the distributions of consecutive rainy days, rainfall deficits and extreme 24-hour rainfall were modelled. Spatial interpolation of GEV-derived return levels resulted in maps of extreme precipitation, precipitation deficits and wet periods. The degree of temporal overlap between extreme weather conditions and sensitive periods in the agro-ecosystem was determined using a bio-physically based modelling framework that couples phenological models, a soil water balance, crop growth and environmental models. 20-year return values were derived for frost, heat stress, drought, waterlogging and field access during different sensitive stages for different arable crops. Extreme yield values were detected from detrended long term arable yields and relationships were found with soil moisture conditions, heat stress or other meteorological variables during the

  15. STATE AND EFFICIENCY OF MANAGEMENT OF AGROECOSYSTEM SERVICES – THE CASE OF BULGARIA

    Directory of Open Access Journals (Sweden)

    HRABRIN BACHEV

    2010-01-01

    Full Text Available This paper incorporates New Institutional Economics and analyzes the state and efficiency of management of agro-ecosystem services in Bulgaria. Firstly, it presents framework of analyses of management of agro-ecosystem services including: definition of agroecosystem services and its management; specification of management needs and spectrum of governing modes (institutions, market, private, public, hybrid; assessment of efficiency of different form of management in terms of potential to protect eco-rights and investments, assure socially desirable level of agro-ecosystem services, minimize costs, coordinate and stimulate eco-activities, meet preferences and reconcile conflicts of related agents. Secondly, it identifies and assesses the management of agro-ecosystem services in Bulgaria. Transition and EU integration have brought about significant changes in the state and management of agroecosystems services in the country. Newly evolved market, private and public governance have led to a significant improvement of a part of agro-ecosystems services introducing modern ecostandards and public support, enhancing environmental stewardship, disintensifyingproduction, recovering landscape and traditional productions, diversifying quality, products,and services. At the same time, the novel eco-management is associated with new challenges such as unsustainable exploitation, lost biodiversity, land degradation, water and air contamination. Moreover, implementation of EU common policies would have no desired impact on agro-ecosystem services unless special measures are taken to improve management of public programs, and extend public support to dominating small-scale and subsistence farms.

  16. Managing biotic interactions for ecological intensification of agroecosystem

    Directory of Open Access Journals (Sweden)

    Sabrina eGaba

    2014-06-01

    Full Text Available Agriculture faces the challenge of increasing food production while simultaneously reducing the use of inputs and delivering other ecosystem services. Ecological intensification of agriculture is a paradigm shift, which has recently been proposed to meet such challenges through the manipulation of biotic interactions. While this approach opens up new possibilities, there are many constraints related to the complexity of agroecosystems that make it difficult to implement. Future advances, which are essential to guide agricultural policy, require an eco-evolutionary framework to ensure that ecological intensification is beneficial in the long term.

  17. Agro-ecosystem Emergy Evolution and Trend in Hunan Province

    OpenAIRE

    2012-01-01

    Using the emergy analysis method, we conduct trend analysis of changes in the total emergy, input and output structure, various emergy indicators of agro-ecosystem in Hunan Province during the period 1999-2008. The results show that during the study period, total emergy input basically remained stable, but the emergy input structure was constantly optimized, of which the input of non-renewable industrial assistant emergy increased by 38.4%, from 4.00E+22 sej to 5.53E+22 sej, and the input of ...

  18. [Changes of agroecosystem service value during urbanization of Guangzhou City, South China].

    Science.gov (United States)

    Ye, Yan-Qiong; Li, Yi-Mian; Zhang, Jia-En

    2011-06-01

    Based on the 1996, 2000, 2004, and 2008 statistical data of Guangzhou City, and by the methods of marketing valuation, shadow price, afforestation cost, carbon tax, and industrial oxygen-producing, this paper calculated the related service values of various agroecosystems in Guangzhou, and assessed the changes of agroecosystem service value during the rapid urbanization of the City. In 1996-2008, though the service values of farmland, grassland, and water ecosystems had somewhat increase, the overall agroecosystem service value of Guangzhou decreased, mainly due to the more decrease of forest ecosystem service value which occupied more than 90% of the total service value each year. Over the studied period, the proportion of each individual functional service value to the total service value changed little, and the contribution of each individual functional service value was in the order of climate regulation > gases regulation > product service > waste treatment > soil conservation > biodiversity conservation > recreation and culture > water source retention and storage. The sum of climate regulation and gases regulation service values took over 91% of the total agroecosystem service value. There was a significant negative correlation (R = -0.905, P agroecosystem service value, suggesting that the increase of urbanization rate would lead to a decrease of agroecosystem service value. Therefore, it requires an appropriate reservation of various agroecosystems to maintain the regional sustainable development during urbanization.

  19. [Edge effect on the dynamics of pests and natural enemies in cotton agroecosystems].

    Science.gov (United States)

    Ge, Feng; Men, Xingyuan; Su, Jianwei; Liu, Xinghui; Ding, Yanqin

    2004-01-01

    Investigation on the population dynamics of pests and natural enemies on the cotton plants in the middle and edge of cotton agroecosystems showed that the population of the 2nd generation of cotton bollworms (Heliocopavar armigia) and seedling aphids (Aphis gossyppi) was respectively 1.94 times and 1.09 times higher, but that of the 3rd generation cotton bollworms and summer aphids population was respectively 62.12% and 97.73% lower in the edge than in the middle of cotton agroecosystem. The population of predacious ladybeetles, predacious bugs, spiders and parasites in the edge of cotton agroecosystem was 73.81%, 35.79%, 52.90% and 39.11% of that in the middle of cotton agroecosystem, respectively. The greater diversity of pest community and the less diversity of natural enemies community were found in the edge than in the middle of cotton agroecosystem. The increase of energy utilization efficiency and gross production in the edge of cotton agroecosystems showed the edge effect of cotton agroecosystems.

  20. Carbon Sequestration in Dryland and Irrigated Agroecosystems: Quantification at Different Scales for Improved Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Shashi B; Cassman, Kenneth G; Arkebauer, Timothy J; Hubbard, Kenneth G; Knops, Johannes M; Suyker, Andrew E

    2012-09-14

    The overall objective of this research is to improve our basic understanding of the biophysical processes that govern C sequestration in major rainfed and irrigated agroecosystems in the north-central USA.

  1. Climbing a ladder: a step-by-step approach to understanding the concept of agroecosystem health.

    Science.gov (United States)

    Alkorta, I; Albizu, I; Amezaga, I; Onaindia, M; Buchner, V; Garbisu, C

    2004-01-01

    Population and individual health is linked to agroecosystem health. To comprehend the concept of agroecosystem health, one should climb a ladder consisting of several successive steps, each rung presenting a certain degree of instability (conceptual difficulty and uncertainty) in an advisable but not inevitable order. Here we suggest a ladder consisting of the following concepts: ecosystem, agroecosystem, biodiversity, sustainability, ecosystem health, and agroecosystem health. Although these concepts are to a certain extent well understood and grasped by scientists, politicians, natural resource managers, and environmentalists, some steps are still highly debatable, unclear, and present a considerable degree of reluctance to be defined and understood. Consequently, much empirical and theoretical effort must be made to construct solid conceptual ladders made up of such steps. In this enterprise, a traditional reductionistic approach confining interpretations to narrow scientific disciplines is unadvisable. Holistic, transdisciplinary approaches are required to reach the desired goal.

  2. [A discussion on basic content and evaluation index system of agroecosystem health].

    Science.gov (United States)

    Zhang, Jia'en; Luo, Shiming

    2004-08-01

    Agroecosystem health is the fundament of food security and human health, and becoming one of the hot spots and frontier fields in agricultural ecology study with more and more international concerns, which can be interpreted as a sustainable state and a dynamic process involving good eco-environment, healthy agricultural organisms, rational spatial and temporal structure, clean production pattern, optimal biodiversity and high productivity. Agroecosystem is a kind of typical artificial and natural compound ecosystem. Its health is strongly influenced and controlled by human activities, and usually linked with agro-products quality, food security and biological security. A series of indices including biological, environmental and eco-economic indicators could be integrated to assess the situation and level of agroecosystem health, and some methods including comprehensive index assessment, eco-toxicological assessment and ecological risk assessment could be used for the evaluation of agroecosystem health.

  3. How should we be determining background and baseline antibiotic resistance levels in agroecosystem research?

    Science.gov (United States)

    Although historically antibiotic resistance has occurred naturally in environmental bacteria, many questions remain regarding the specifics of how humans and animals contribute to the development and spread of antibiotic resistance in agroecosystems. Additional research is necessary to completely u...

  4. [Effect of transgenic plants on biodiversity of agroecosystem].

    Science.gov (United States)

    Nie, Chengrong; Wang, Jianwu; Luo, Shiming

    2003-08-01

    The effect of transgenic plants on the biodiversity of agroecosystem is an important environmental issue. There are many researches in this field at home and abroad recently. This paper reviewed the advances of the researches based on three levels of biodiversity as genetic diversity, species diversity and ecosystem diversity. They included following aspects: the effect of insect-resistant transgenic crops on target pest; the effect of herbicide-resistant transgenic crops on crops and wild weedy relatives; the effect of virus-resistant transgenic crops on virus; and the effect of transgenic crops on non-target organisms. This paper also discussed the effect of transgenic crops on soil ecosystem and crop genetic diversity. Their potential risks included uncontrolled flows of genes to wild relatives; development of herbicide, insect, and virus resistance in wild relatives; reduced crop genetic diversity; and adverse effects on organisms that were not pests, such as beneficial insects.

  5. Influence of growing and exploatation of bovins on regional agroecosystems

    Directory of Open Access Journals (Sweden)

    Cornel Podar

    2011-12-01

    Full Text Available Scientists all over the are concerned regarding the influence of growing ruminants on regional agro-ecosystems due to green house gases resulted (CO 2, CH4, N2O5. Cattle have contributed to environmental pollution in old industrial farming systems, when the cattle number in Romania, reached 8 million, manure evacuation was not solved and manure was accumulating around the farm polluting the soil, water and air. Low density of ruminants existing in the agricultural sector of the country is not significant in terms of pollution. Currently cattle have positive effects on the environment by the use of legumes, grasses and manure production contributing to the increase of agricultural production: crop production (sugar beet, potato and cereals, animal production (milk, meat, leather production and industrial production also (biogas, befouls, alcohol, oil production.

  6. Predicting the global warming potential of agro-ecosystems

    Directory of Open Access Journals (Sweden)

    S. Lehuger

    2007-04-01

    Full Text Available Nitrous oxide, carbon dioxide and methane are the main biogenic greenhouse gases (GHG contributing to the global warming potential (GWP of agro-ecosystems. Evaluating the impact of agriculture on climate thus requires a capacity to predict the net exchanges of these gases in an integrated manner, as related to environmental conditions and crop management. Here, we used two year-round data sets from two intensively-monitored cropping systems in northern France to test the ability of the biophysical crop model CERES-EGC to simulate GHG exchanges at the plot-scale. The experiments involved maize and rapeseed crops on a loam and rendzina soils, respectively. The model was subsequently extrapolated to predict CO2 and N2O fluxes over an entire crop rotation. Indirect emissions (IE arising from the production of agricultural inputs and from cropping operations were also added to the final GWP. One experimental site (involving a wheat-maize-barley rotation on a loamy soil was a net source of GHG with a GWP of 350 kg CO2-C eq ha−1 yr−1, of which 75% were due to IE and 25% to direct N2O emissions. The other site (involving an oilseed rape-wheat-barley rotation on a rendzina was a net sink of GHG for –250 kg CO2-C eq ha−1 yr−1, mainly due to a higher predicted C sequestration potential and C return from crops. Such modelling approach makes it possible to test various agronomic management scenarios, in order to design productive agro-ecosystems with low global warming impact.

  7. SATELLITE DRIVEN ESTIMATION OF PRIMARY PRODUCTIVITY OF AGROECOSYSTEMS IN INDIA

    Directory of Open Access Journals (Sweden)

    N. R. Patel

    2012-08-01

    Full Text Available Earth observation driven ecosystem modeling have played a major role in estimation of carbon budget components such as gross primary productivity (GPP and net primary production (NPP over terrestrial ecosystems, including agriculture. The present study therefore evaluate satellite-driven vegetation photosynthesis (VPM model for GPP estimation over agro-ecosystems in India by using time series of the Normalized Difference Vegetation Index (NDVI from SPOT-VEGETATION, cloud cover observation from MODIS, coarse-grid C3/C4 crop fraction and decadal grided databases of maximum and minimum temperatures. Parameterization of VPM parameters e.g. maximum light use efficiency (ε* and Tscalar was done based on eddy-covariance measurements and literature survey. Incorporation of C3/C4 crop fraction is a modification to commonly used constant maximum LUE. Modeling results from VPM captured very well the geographical pattern of GPP and NPP over cropland in India. Well managed agro-ecosystems in Trans-Gangetic and upper Indo-Gangetic plains had the highest magnitude of GPP with peak GPP during kharif occurs in sugarcane-wheat system (western UP and it occurs in rice-wheat system (Punjab during Rabi season. Overall, croplands in these plains had more annual GPP (> 1000 g C m-2 and NPP (> 600 g C m-2 due to input-intensive cultivation. Desertic tracts of western Rajasthan showed the least GPP and NPP values. Country-level contribution of croplands to national GPP and NPP amounts to1.34 Pg C year-1 and 0.859 Pg C year-1, respectively. Modeled estimates of cropland NPP agrees well with ground-based estimates for north-western India (R2 = 0.63 and RMSE = 108 g C m-2. Future research will focus on evaluating the VPM model with medium resolution sensors such as AWiFS and MODIS for rice-wheat system and validating with eddy-covariance measurements.

  8. Migrant farmers as information brokers: agroecosystem management in the transition zone of Ghana

    OpenAIRE

    Marney E. Isaac; Luke C. N. Anglaaere; Daniel S. Akoto; Evans Dawoe

    2014-01-01

    Environmentally induced farmer migration is an important livelihood strategy, yet little is known of the effects on the destination region agroecosystem information networks and management practices. In the forest-savanna transition zone (Brong Ahafo Region) of Ghana, where migration from northern regions (migrant) and from neighboring regions (settler) is active, we chart the role of migrant famers and the type of agroecosystem management practices embedded in information networks using a so...

  9. Sustainable and resource efficient intensivation of crop production - Perspectives of agro-ecosystem research Policy paper of the DFG Senate Commission on Agroecosystem Research

    NARCIS (Netherlands)

    Wolters, V.; Isselstein, J.; Stützel, H.; Ordon, F.; Haaren, von C.; Schlecht, E.; Wesseler, J.H.H.; Birner, R.; Lützow, von M.; Brüggemann, N.; Diekkrüger, B.; Fangmeier, A.; Flessa, H.; Kage, H.; Kaupenhohann, M.; Kögel-Knabner, I.; Mosandl, R.; Seppelt, R.

    2014-01-01

    With its policy paper the Senate Commission on Agro-ecosystemResearch of the Deutsche Forschungsgemeinschaft(DFG) summarizes potential benefits of basic researchfor the sustainable intensification of crop production. Agro-ecosystems critically contribute to fulfilling the need forincreasing food and

  10. Direct field method for root biomass quantification in agroecosystems.

    Science.gov (United States)

    Frasier, Ileana; Noellemeyer, Elke; Fernández, Romina; Quiroga, Alberto

    2016-01-01

    The present article describes a field auger sampling method for row-crop root measurements. In agroecosystems where crops are planted in a specific design (row crops), sampling procedures for root biomass quantification need to consider the spatial variability of the root system. This article explains in detail how to sample and calculate root biomass considering the sampling position in the field and the differential weight of the root biomass in the inter-row compared to the crop row when expressing data per area unit. This method is highly reproducible in the field and requires no expensive equipment and/or special skills. It proposes to use a narrow auger thus reducing field labor with less destructive sampling, and decreases laboratory time because samples are smaller. The small sample size also facilitates the washing and root separation with tweezers. This method is suitable for either winter- or summer crop roots. •Description of a direct field method for row-crop root measurements.•Description of data calculation for total root-biomass estimation per unit area.•The proposed method is simple, less labor- and less time consuming.

  11. Biodiversity conservation in tropical agroecosystems: a new conservation paradigm.

    Science.gov (United States)

    Perfecto, Ivette; Vandermeer, John

    2008-01-01

    It is almost certainly the case that many populations have always existed as metapopulations, leading to the conclusion that local extinctions are common and normally balanced by migrations. This conclusion has major consequences for biodiversity conservation in fragmented tropical forests and the agricultural matrices in which they are embedded. Here we make the argument that the conservation paradigm that focuses on setting aside pristine forests while ignoring the agricultural landscape is a failed strategy in light of what is now conventional wisdom in ecology. Given the fragmented nature of most tropical ecosystems, agricultural landscapes should be an essential component of any conservation strategy. We review the literature on biodiversity in tropical agricultural landscapes and present evidence that many tropical agricultural systems have high levels of biodiversity (planned and associated). These systems represent, not only habitat for biodiversity, but also a high-quality matrix that permits the movement of forest organisms among patches of natural vegetation. We review a variety of agroecosystem types and conclude that diverse, low-input systems using agroecological principles are probably the best option for a high-quality matrix. Such systems are most likely to be constructed by small farmers with land titles, who, in turn, are normally the consequence of grassroots social movements. Therefore, the new conservation paradigm should incorporate a landscape approach in which small farmers, through their social organizations, work with conservationists to create a landscape matrix dominated by productive agroecological systems that facilitate interpatch migration while promoting a sustainable and dignified livelihood for rural communities.

  12. Agro-ecosystem Emergy Evolution and Trend in Hunan Province

    Institute of Scientific and Technical Information of China (English)

    ZHU Yu-lin; LI Ming-jie; HOU Mao-zhang; LI Sha; LONG Yu-zi; WANG Mao-xi

    2012-01-01

    Using the emergy analysis method,we conduct trend analysis of changes in the total emergy,input and output structure,various emergy indicators of agro-ecosystem in Hunan Province during the period 1999-2008.The results show that during the study period,total emergy input basically remained stable,but the emergy input structure was constantly optimized,of which the input of non-renewable industrial assistant emergy increased by 38.4%,from 4.00E +22 sej to 5.53E +22 sej,and the input of renewable organic emergy declined from 1.32E +23 sej to 1.20E + 23 sej;total emergy yield and yield efficiency of this system were promoted dramatically,and in 2008,the total emergy yield reached 1.69E +23 sej,increasing by 23.8% as against that in 1999,the net emergy yield ratio rose from 0.79 to 0.96;since the environmental loading ratio also tended to rise constantly,from 1.12 to 1.79,the sustainability index of this system also experienced the slow downward trend,from 0.71 to 0.54,always less than 1,indicating that the agriculture in Hunan Province is the high consumption-driven ecosystem in general,with obvious features of extensive development.

  13. Understanding Relationships among Agro-Ecosystem Services Based on Emergy Analysis in Luancheng County, North China

    Directory of Open Access Journals (Sweden)

    Fengjiao Ma

    2014-11-01

    Full Text Available Exploring the relationship between different services has become the focus of ecosystem services research in recent years. The agro-ecosystem, which accounts for one-third of the global land area, provides lots of services but also disservices, depending on resources provided by other systems. In this paper, we explored the agro-ecosystem from four aspects: a summary of different indicators in the agro-ecosystem, input and output changes with time, relationships between different ecosystem services and disservices, and resource contribution to major services, using Luancheng County of North China as the study area. We then used emergy analysis to unify all the indicators. The conclusions were that the agro-ecosystem maintained provisioning and regulating services but with increasing volatility under continued growth in production inputs and disservice outputs. There was a positive correlation between most of the different services and disservices. Rainfall and groundwater resources were the most used input resources in the agro-ecosystem and all other major ecosystem services depended directly on them.

  14. Crop rotational diversity enhances belowground communities and functions in an agroecosystem.

    Science.gov (United States)

    Tiemann, L K; Grandy, A S; Atkinson, E E; Marin-Spiotta, E; McDaniel, M D

    2015-08-01

    Biodiversity loss, an important consequence of agricultural intensification, can lead to reductions in agroecosystem functions and services. Increasing crop diversity through rotation may alleviate these negative consequences by restoring positive aboveground-belowground interactions. Positive impacts of aboveground biodiversity on belowground communities and processes have primarily been observed in natural systems. Here, we test for the effects of increased diversity in an agroecosystem, where plant diversity is increased over time through crop rotation. As crop diversity increased from one to five species, distinct soil microbial communities were related to increases in soil aggregation, organic carbon, total nitrogen, microbial activity and decreases in the carbon-to-nitrogen acquiring enzyme activity ratio. This study indicates positive biodiversity-function relationships in agroecosystems, driven by interactions between rotational and microbial diversity. By increasing the quantity, quality and chemical diversity of residues, high diversity rotations can sustain soil biological communities, with positive effects on soil organic matter and soil fertility.

  15. Agrobiodiversity of Muda Rice Agroecosystem:A case Study in Largest Granary Area of Malaysia

    Institute of Scientific and Technical Information of China (English)

    Amir Shah Ruddin Md Shah; Mashhor Mansor; Shahrul Anuar Mohd Shah; Che Salmah Mohd Rawi; Abu Hassan Ahmad; Ibrahim Jaafar

    2008-01-01

    A survey was carried out at the largest rice cultivation area in Peninsular Malaysia, the Muda rice agroecosystem. The main objective of this study was to document the overall biodiversity associated with this unique agroecosystem by using a combination of sampling techniques in order to record different groups of fauna and flora. The total number of biota recorded and identified from the rice field ecosystem during the study period consisted of 46 species of zooplankton, 81 species of aquatic insects, 5 species of rodents, 7 species of bats, 87 species of birds, 11 species of fishes and 58 species of weeds. A long-term study should be carried out as more species are expected to be recorded when more of the Muda rice agroecosystem area has been sampled to obtain sufficient information on the Muda rice agrobiodiversity.

  16. Mosquito species diversity and abundance in relation to land use in a riceland agroecosystem in Mwea, Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Shililu, Josephat; Jacob, Benjamin; Gu, Weidong; Githure, John; Novak, Robert

    2006-06-01

    We conducted an entomological survey to determine the mosquito species diversity and abundance in relation to land use in the Mwea rice scheme, Kenya. Adult mosquitoes were collected by indoor spraying of houses and outdoors by CDC light traps in three villages representing planned (Mbuinjeru) and unplanned (Kiamachiri) rice agroecosystems and a non-irrigated agroecosystem (Murinduko). During the 12-month sampling period, a total of 98,708 mosquitoes belonging to five genera and 25 species were collected. The five most common species collected during this study were Anopheles arabiensis Patton (52.5%), Culex quinquefasciatus Say (36.7%), Anopheles pharoensis Theobald (5.2%), Anopheles coustani Laveran (1.4%), and Anopheles funestus Giles (1.3%). Anopheles arabiensis, Cx quinquefasciatus, and An. pharoensis were more abundant in rice agroecosystems than in the non-irrigated agroecosystem, and in planned than in the unplanned rice agroecosystems. In contrast, An. funestus was more abundant in the non-irrigated agroecosystem. The mosquito species diversity (H) and evenness (E(H)) in the non-irrigated agroecosystem (Shannon diversity Index, H = 1.507, EH = 0.503) was significantly higher than in the rice agroecosystems (H) = 0.968, E(H) = 0.313, unplanned; and H= 1.040, E(H) = 0.367 planned). Results of lag cross correlation analysis revealed a strong relationship between rainfall and the abundance of An. arabiensis, and C. quinquefasciatus in the non-irrigated agroecosystem but not in the rice agroecosystems. It is inferred from the data that different levels of habitat perturbations with regard to rice cultivation have different effects on mosquito diversity and abundance. This provides an understanding of how mosquito diversity is impacted by different habitat management and rice cropping strategies.

  17. Production and robustness of a Cacao agroecosystem: effects of two contrasting types of management strategies.

    Science.gov (United States)

    Sabatier, Rodolphe; Wiegand, Kerstin; Meyer, Katrin

    2013-01-01

    Ecological intensification, i.e. relying on ecological processes to replace chemical inputs, is often presented as the ideal alternative to conventional farming based on an intensive use of chemicals. It is said to both maintain high yield and provide more robustness to the agroecosystem. However few studies compared the two types of management with respect to their consequences for production and robustness toward perturbation. In this study our aim is to assess productive performance and robustness toward diverse perturbations of a Cacao agroecosystem managed with two contrasting groups of strategies: one group of strategies relying on a high level of pesticides and a second relying on low levels of pesticides. We conducted this study using a dynamical model of a Cacao agroecosystem that includes Cacao production dynamics, and dynamics of three insects: a pest (the Cacao Pod Borer, Conopomorpha cramerella) and two characteristic but unspecified beneficial insects (a pollinator of Cacao and a parasitoid of the Cacao Pod Borer). Our results showed two opposite behaviors of the Cacao agroecosystem depending on its management, i.e. an agroecosystem relying on a high input of pesticides and showing low ecosystem functioning and an agroecosystem with low inputs, relying on a high functioning of the ecosystem. From the production point of view, no type of management clearly outclassed the other and their ranking depended on the type of pesticide used. From the robustness point of view, the two types of managements performed differently when subjected to different types of perturbations. Ecologically intensive systems were more robust to pest outbreaks and perturbations related to pesticide characteristics while chemically intensive systems were more robust to Cacao production and management-related perturbation.

  18. The value of producing food, energy, and ecosystem services within an agro-ecosystem

    DEFF Research Database (Denmark)

    Porter, John Roy; Constanza, Robert; Sandhu, Harpinder;

    2009-01-01

    Ecosystem Services within an Agro- Ecosystem Agricultural ecosystems produce food, fiber, and nonmarketed ecosystem services (ES). Agriculture also typically involves high negative external costs associated with, for example, fossil fuel use. We estimated, via fieldscale ecological monitoring...... and economic value-transfer methods, the market and nonmarket ES value of a combined food and energy (CFE) agro-ecosystem that simultaneously produces food, fodder, and bioenergy. Such novel CFE agro-ecosystems can provide a significantly increased net crop, energy, and nonmarketed ES compared...

  19. Fruit and soil quality of organic and conventional strawberry agroecosystems.

    Directory of Open Access Journals (Sweden)

    John P Reganold

    Full Text Available BACKGROUND: Sale of organic foods is one of the fastest growing market segments within the global food industry. People often buy organic food because they believe organic farms produce more nutritious and better tasting food from healthier soils. Here we tested if there are significant differences in fruit and soil quality from 13 pairs of commercial organic and conventional strawberry agroecosystems in California. METHODOLOGY/PRINCIPAL FINDINGS: At multiple sampling times for two years, we evaluated three varieties of strawberries for mineral elements, shelf life, phytochemical composition, and organoleptic properties. We also analyzed traditional soil properties and soil DNA using microarray technology. We found that the organic farms had strawberries with longer shelf life, greater dry matter, and higher antioxidant activity and concentrations of ascorbic acid and phenolic compounds, but lower concentrations of phosphorus and potassium. In one variety, sensory panels judged organic strawberries to be sweeter and have better flavor, overall acceptance, and appearance than their conventional counterparts. We also found the organically farmed soils to have more total carbon and nitrogen, greater microbial biomass and activity, and higher concentrations of micronutrients. Organically farmed soils also exhibited greater numbers of endemic genes and greater functional gene abundance and diversity for several biogeochemical processes, such as nitrogen fixation and pesticide degradation. CONCLUSIONS/SIGNIFICANCE: Our findings show that the organic strawberry farms produced higher quality fruit and that their higher quality soils may have greater microbial functional capability and resilience to stress. These findings justify additional investigations aimed at detecting and quantifying such effects and their interactions.

  20. PHOSPHORUS BIOGEOCHEMICAL CYCLING IN A SUGAR CANE AGROECOSYSTEM

    Directory of Open Access Journals (Sweden)

    D. Lopez-Hernandez

    2012-01-01

    Full Text Available The annual harvest of sugarcane plantations together with the burning of the crop before harvest, a common practice of management of sugarcane plantations in South America, leads to the loss of significant amounts of nutrients in those agroecosystems. Thus prescribed burning operations could progressively diminish the level of soil organic matter and increase nutrient deficiency in soils of sugar cane agrosystems. This study is an attempt to quantify the P distribution during the period of growth in a plantation of sugar cane (Saccharum officinarum located near San Felipe, Yaracuy State, Central, Venezuela focusing on processes related to the cycling of the element as affected by burning operations. The work was performed in 4.5 ha experimental plots planted with the varieties Puerto Rico (PR 1028 and Venezuela (V 58-4. The principal flows of phosphorus, as well the quantities of this element in the soil-plant components were measured throughout the growing cycle of the crop (third ratoon. The inputs through precipitation (wet and dry were high, that was associated with the intense agricultural (prescribed burning and industrial activities occurring in the area. The annual balance for both varieties was negative (-17.31 and -23.63 kg ha–1 for V 58-4 and PR 1028, respectively. The negative budget is mainly due to the important amounts of P that are exported with the cane stems. The losses must be compensated through fertilization; nonetheless, preliminary results indicated no response to P dressing, suggesting that in the studied mollisols the internal processes e.g., Organic-P (Po mineralization and P solubilization efficiently operate generating important available P levels. It was also found that the burning of the sugar cane plantation plays an important role in the recycling of phosphorus, since 25-28 % of the P requirements of the varieties are reincorporated into the soil from the ashes coming as bulk deposition.

  1. Ecohydrology of agroecosystems: quantitative approaches towards sustainable irrigation.

    Science.gov (United States)

    Vico, Giulia; Porporato, Amilcare

    2015-02-01

    Irrigation represents one of the main strategies to enhance and stabilize agricultural productivity, by mitigating the effects of rainfall vagaries. In the face of the projected growth in population and in biofuel demands, as well as shifts in climate and dietary habits, a more sustainable management of water resources in agroecosystems is needed. The field of ecohydrology, traditionally focusing on natural ecosystems, has the potential to offer the necessary quantitative tools to assess and compare agricultural enterprises across climates, soil types, crops, and irrigation strategies, accounting for the unpredictability of the hydro-climatic forcing. Here, agricultural sustainability and productivity are assessed with reference to water productivity (defined as the ratio between yield and total supplied water), yields, water requirements, and their variability-a crucial element for food security and resource allocation planning. These synthetic indicators are quantified by means of a probabilistic description of the soil water balance and crop development. The model results allow the interpretation of patterns of water productivity observed in Zea mays (maize) and Triticum aestivum (wheat), grown under a variety of soils, climates, and irrigation strategies. Employing the same modeling framework, the impact of rainfall pattern and irrigation strategy on yield and water requirements is further explored. The obtained standard deviations of yield and water requirements suggest the existence of a nonlinear tradeoff between yield stabilization and variability of water requirements, which in turn is strongly impacted by irrigation strategy. Moreover, intermediate rainfall amounts are associated to the highest variability in yields and irrigation requirements, although allowing the maximum water productivity. The existence of these tradeoffs between productivity, reliability, and sustainability poses a problem for water management, in particular in mesic climates.

  2. Socio-Cultural and Economic Valuation of Ecosystem Services Provided by Mediterranean Mountain Agroecosystems

    NARCIS (Netherlands)

    Bernues, A.; Rodriguez-Ortega, T.; Ripoll Bosch, R.; Alfnes, F.

    2015-01-01

    The aim of this work was to elucidate the socio-cultural and economic value of a number of ecosystem services delivered by mountain agroecosystems (mostly grazing systems) in Euro-Mediterranean regions. We combined deliberative (focus groups) and survey-based stated-preference methods (choice modell

  3. Manual for semi-detailed characterization of inland valley agro-ecosystems

    NARCIS (Netherlands)

    Duivenbooden, van N.; Windmeijer, P.N.

    1995-01-01

    The project "Characterization of Rice-growing Agro-ecosystems in West Africa" and its successor "The Consortium for Sustainable Use of Inland Valleys in Sub-Saharan Africa" aim at developing suitable technologies of soil, water and crop management for more-intensive utilization of inland valleys for

  4. Perspectives on allelopathy in mexican traditional agroecosystems: A case study in tlaxcala.

    Science.gov (United States)

    Anaya, A L; Ramos, L; Cruz, R; Hernández, J G; Nava, V

    1987-11-01

    Agroecosystems in Tlaxcala, Mexico, are surrounded by trees and water channels and have a great variety of cultivated and noncultivated plants. The main results of a study carried out on a traditional agroecosystem in Santa Inés, Tlaxcala are presented. Some ecological aspects of polycultures, plant covers (dry leaves ofAlnus firmifolia, Berula erecta, andJuncus sp.), and the allelopathic potential of crops and noncultivated plants (fresh and dry material) were analyzed. The main plants (trees, shrubs, and herbs) present in the agroecosystem were identified. The total number of weeds in plots where plant covers were added was reduced. The number of nodules ofRhizobium phaseoli and the production of bean and squash increased with plant covers. Corn, beans, and squash showed a clear allelopathic effect, as well asChenopodium murale, Tradescantia crassifolia, Melilotus indicus, andAmaranthus hybridus, among other weeds. The contribution of allelopathy in studies of traditional agroecosystems is of great importance for the management of species in space and time. Allelopathy can be the basis of biological control of pests and weeds and of the discovery of new useful substances.

  5. Socio-Cultural and Economic Valuation of Ecosystem Services Provided by Mediterranean Mountain Agroecosystems

    NARCIS (Netherlands)

    Bernues, A.; Rodrıguez-Ortega, T.; Ripoll Bosch, R.; Alfnes, F.

    2014-01-01

    The aim of this work was to elucidate the socio-cultural and economic value of a number of ecosystem services delivered by mountain agroecosystems (mostly grazing systems) in Euro-Mediterranean regions. We combined deliberative (focus groups) and survey-based stated-preference methods (choice modell

  6. Modelling Mediterranean agro-ecosystems by including agricultural trees in the LPJmL model

    Science.gov (United States)

    Fader, M.; von Bloh, W.; Shi, S.; Bondeau, A.; Cramer, W.

    2015-11-01

    In the Mediterranean region, climate and land use change are expected to impact on natural and agricultural ecosystems by warming, reduced rainfall, direct degradation of ecosystems and biodiversity loss. Human population growth and socioeconomic changes, notably on the eastern and southern shores, will require increases in food production and put additional pressure on agro-ecosystems and water resources. Coping with these challenges requires informed decisions that, in turn, require assessments by means of a comprehensive agro-ecosystem and hydrological model. This study presents the inclusion of 10 Mediterranean agricultural plants, mainly perennial crops, in an agro-ecosystem model (Lund-Potsdam-Jena managed Land - LPJmL): nut trees, date palms, citrus trees, orchards, olive trees, grapes, cotton, potatoes, vegetables and fodder grasses. The model was successfully tested in three model outputs: agricultural yields, irrigation requirements and soil carbon density. With the development presented in this study, LPJmL is now able to simulate in good detail and mechanistically the functioning of Mediterranean agriculture with a comprehensive representation of ecophysiological processes for all vegetation types (natural and agricultural) and in a consistent framework that produces estimates of carbon, agricultural and hydrological variables for the entire Mediterranean basin. This development paves the way for further model extensions aiming at the representation of alternative agro-ecosystems (e.g. agroforestry), and opens the door for a large number of applications in the Mediterranean region, for example assessments of the consequences of land use transitions, the influence of management practices and climate change impacts.

  7. Modelling Mediterranean agro-ecosystems by including agricultural trees in the LPJmL model

    Directory of Open Access Journals (Sweden)

    M. Fader

    2015-06-01

    Full Text Available Climate and land use change in the Mediterranean region is expected to affect natural and agricultural ecosystems by decreases in precipitation, increases in temperature as well as biodiversity loss and anthropogenic degradation of natural resources. Demographic growth in the Eastern and Southern shores will require increases in food production and put additional pressure on agro-ecosystems and water resources. Coping with these challenges requires informed decisions that, in turn, require assessments by means of a comprehensive agro-ecosystem and hydrological model. This study presents the inclusion of 10 Mediterranean agricultural plants, mainly perennial crops, in an agro-ecosystem model (LPJmL: nut trees, date palms, citrus trees, orchards, olive trees, grapes, cotton, potatoes, vegetables and fodder grasses. The model was successfully tested in three model outputs: agricultural yields, irrigation requirements and soil carbon density. With the development presented in this study, LPJmL is now able to simulate in good detail and mechanistically the functioning of Mediterranean agriculture with a comprehensive representation of ecophysiological processes for all vegetation types (natural and agricultural and in a consistent framework that produces estimates of carbon, agricultural and hydrological variables for the entire Mediterranean basin. This development pave the way for further model extensions aiming at the representation of alternative agro-ecosystems (e.g. agroforestry, and opens the door for a large number of applications in the Mediterranean region, for example assessments on the consequences of land use transitions, the influence of management practices and climate change impacts.

  8. Addressing law and agroecosystems, sovereignty and sustainability from a legal pluralistic perspective

    NARCIS (Netherlands)

    Hospes, O.

    2015-01-01

    This paper wants to contribute to the debate on the complex relationships between law and agroecosystems from a legal pluralistic perspective. For this purpose, it first explains what is legal pluralism, and then this notion is used to conceptualize law, the relationship between law and social field

  9. Keeping N in its place: Legumes and N cycling in agro-ecosystems

    Science.gov (United States)

    The extent to which legumes add and retain N in agro-ecosystems depends on plant, rhizobial, soil, and weather conditions and on crop management. In some regions, deeply rooted alfalfa removes subsoil nitrate and water, reducing nitrogen (N) losses through leaching and tile drainage, fixes the remai...

  10. Insect behavioural ecology and other factors affecting the control efficacy of agro-ecosystem diversification strategies

    NARCIS (Netherlands)

    Potting, R.P.J.; Perry, J.N.; Powell, W.

    2005-01-01

    In the last decade there is an increased interest in the design and use of diversified pest-suppressive agro-ecosystems. A diversification approach aims to manipulate the spatial dynamics of herbivores by adding a trap crop that attracts and retains herbivores in the non-crop area or by adding a dis

  11. Hierarchical levels in agro-ecosystems: selective case studies on water and nitrogen.

    NARCIS (Netherlands)

    Ridder, de N.

    1997-01-01

    The subject of this thesisToday, agronomic research faces the triple challenge to develop knowledge and insight to manage agro-ecosystems which are inherently sustainable, to diminish the undesirable side effects and to meet the increasing demand of food of a still growing world population, without

  12. [Emergy evaluation and dynamic measurement analysis of agro-ecosystems in Sichuan Province of Southwest China].

    Science.gov (United States)

    Zhang, Ying-Cong; Du, Shou-Hu

    2012-03-01

    Agro-ecosystem is the most basic system for human beings survival, while the analysis of the structure and function of the system is the key to solve the problems of agro-ecological environment. In this paper, emergy theory and related economic measurement methods including data envelopment analysis, cointegration test, and error correction model were applied to quantitatively analyze the operation dynamics, environmental loading, operation efficiency, and input-output relation of the agro-ecosystems in Sichuan Province and its 21 cities in 1997-2009. In the study period, Sichuan Province was in the transition period from traditional agriculture to modern agriculture. The agricultural mechanization level of the Province improved constantly, resources utilization efficiency enhanced continually, overall structural dominant degree was better, but the over-reliance on economic emergy input caused the sustainability of the system weakened gradually. The development status of the agro-ecosystems in the Province varied among regions. Chengdu Plain and Western Sichuan Highland were either in overexploited or in underutilized, while the hilly areas were full of vitality and development potential, tended to be the important areas for the future development of Sichuan agriculture. Generally, the operation efficiency of the agro-ecosystems in the Province was relatively low, with the situation differed in different regions due to the lower technical efficiency or improper scale. There was a long-term equilibrium between the economic emergy indices and output emergy, but the short-term emergy input didn't reach the ideal output.

  13. Modeling carbon dynamics and social drivers of bioenergy agroecosystems

    Science.gov (United States)

    Hunt, Natalie D.

    Meeting society's energy needs through bioenergy feedstock production presents a significant and urgent challenge, as it can aid in achieving energy independence goals and mitigating climate change. With federal biofuel production standards to be met within the next decade, and with no commercial scale production or markets currently in place, many questions regarding the sustainability and social feasibility of bioenergy still persist. Clarifying these uncertainties requires the incorporation of biogeochemical, biophysical, and socioeconomic modeling tools. Chapter 2 validated the biogeochemical cycling model AGRO-BGC by comparing model estimates with empirical observations from corn and perennial C4 grass systems across Wisconsin and Illinois. AGRO-BGC, in its first application to an annual cropping system, was found to be a robust model for simulating carbon dynamics of an annual cropping system. Chapter 3 investigated the long-term implications of bioenergy feedstock harvest on soil productivity and erosion in annual corn and perennial switchgrass agroecosystems using AGRO-BGC and the soil erosion model RUSLE2. Modeling environments included biophysical landscape characteristics and management practices of bioenergy feedstock production systems. This study found that intensifying aboveground residue harvest reduces soil productivity over time, and the magnitude of these losses is greater in corn than in switchgrass systems. Results of this study will aid in the design of sustainable bioenergy feedstock management practices. Chapter 4 provided evidence that combining biophysical crop canopy characteristics with satellite-derived vegetation indices offers suitable estimates of crop canopy phenology for corn and soybeans in Southwest Wisconsin farms. LANDSAT based vegetation indices, when combined with a light use efficiency model, provide yield estimates in agreement with farmer reports, providing an efficient and accurate means of estimating crop yields from

  14. Natural biological control of pest mites in Brazilian sun coffee agroecosystems.

    Science.gov (United States)

    Teodoro, Adenir V; Sarmento, Renato A; Rêgo, Adriano S; da Graça S Maciel, Anilde

    2010-06-01

    Coffee is one of the leading commodities in tropical America. Although plantations are usually established under a canopy of trees in most producing countries in the region, Brazilian coffee is mostly produced under full sun conditions. Such simple, single-crop agroecosystems with intensive agrochemical inputs often suffer with pests like mites. Predatory mites of the family Phytoseiidae are the main natural enemies associated with pest mites in the field. However, these beneficial arthropods struggle to survive in intensive agroecosystems such as coffee monocultures due to unfavorable microclimatic conditions, widespread pesticide use, and lack of alternative food (pollen, nectar). Conservation biological control uses a range of management strategies to sustain and enhance populations of indigenous natural enemies such as predatory mites. We discuss here conservation biological control as a strategy to improve biological control of pest mites by native predatory mites in Brazilian coffee monocultures as well as some related patents.

  15. Energy efficiency / economic in agroecosystems; Eficiencia energetica/economica em agroecossistemas

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Luis Carlos Ferreira de; Bueno, Osmar de Carvalho; Esperancini, Maura Seiko Tsutui [Universidade Estadual Paulista Julio de Mesquita Filho (FCA/UNESP), Botucatu, SP (Brazil). Fac. de Ciencias Agronomicas

    2010-07-01

    The energy and economic evaluation of agroecosystems is important in the sense of appraise as maintainable these can be so much of the point of view energy as economic. The objective of the present paper was to show, starting from a case study, the construction of an indicator of energy/economic efficiency, whose results for four existent systems of corn production in the study area presented indexes that varied between 22.4 and 31.6. Of the reading of those values was possible to evaluate that all of the appraised systems show sustainability of long and short term. The proposed indicator if it shows solid in the agroecosystems appreciation concerning the analysis of your energy/economic sustainability. (author)

  16. Biodiversity Indicators for Sustainability Evaluation of Conventional and Organic Agro-ecosystems

    Directory of Open Access Journals (Sweden)

    Concetta Vazzana

    2007-06-01

    Full Text Available Previous studies suggest widespread positive responses of biodiversity to organic farming. However, the effect of organic farming management on biodiversity over time needs to be better understood and this paper aims to compare agricultural biodiversity in a long-term experiment including three different agroecosystem management patterns (old organic, young organic and conventional. The level of agroecosystem sustainability related to plants has been assessed both for the structural and the associated biodiversity, using biodiversity Indicators. The data collected in three years (2003-2005 show that the system under organic agriculture management is better than conventional one for every indicator and it improves each aspect over the time. This trend holds especially for the associated biodiversity while the planned biodiversity can still be improved.

  17. Application of Reduced Corn Cultivation Technology in Agro-Ecosystem of Cazin Municipality

    OpenAIRE

    Mirsad Veladžić; Fatima Muhamedagić; Emdžad Galijašević

    2011-01-01

    Intensive corn cultivation is predominant in current agriculture of the Una-Sana Canton. One of the corn cultivation methods in agro-ecosystem is reduced cultivation. The paper presents the experiment of “Osmak žuti” (eight-row yellow) corn cultivation on two control sites with application of reduced and intensive cultivation in Cazin municipality. The objectives of this research were to examine the possibility of application of reduced corn cultivation; analyze statistical variation elements...

  18. Rapid emergence of pathogens in agro-ecosystems: global threats to agricultural sustainability and food security.

    Science.gov (United States)

    McDonald, Bruce A; Stukenbrock, Eva H

    2016-12-05

    Agricultural ecosystems are composed of genetically depauperate populations of crop plants grown at a high density and over large spatial scales, with the regional composition of crop species changing little from year to year. These environments are highly conducive for the emergence and dissemination of pathogens. The uniform host populations facilitate the specialization of pathogens to particular crop cultivars and allow the build-up of large population sizes. Population genetic and genomic studies have shed light on the evolutionary mechanisms underlying speciation processes, adaptive evolution and long-distance dispersal of highly damaging pathogens in agro-ecosystems. These studies document the speed with which pathogens evolve to overcome crop resistance genes and pesticides. They also show that crop pathogens can be disseminated very quickly across and among continents through human activities. In this review, we discuss how the peculiar architecture of agro-ecosystems facilitates pathogen emergence, evolution and dispersal. We present four example pathosystems that illustrate both pathogen specialization and pathogen speciation, including different time frames for emergence and different mechanisms underlying the emergence process. Lastly, we argue for a re-design of agro-ecosystems that embraces the concept of dynamic diversity to improve their resilience to pathogens. This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.

  19. Characterization of agroecosystems with sheep production in the eastern side of Yucatán, Mexico.

    Directory of Open Access Journals (Sweden)

    Bernardino Candelaria-Martínez

    2015-06-01

    Full Text Available The aim of this study was to characterize and group agroecosystems with sheep production in the eastearn side of Yucatan, Mexico. This study was held from August 2012 to April 2013. A semi-structured questionnaire was applied while interviewing 93% of producers from seven municipalities that have sheep within their agroecosystems. Random sampling, cluster analysis, ANOVA using GLM and comparison of means by Tukey (P>0.05 were performed. Four different groups of agroecosystems with sheep production were obtained: GA (elderly people in charge, middle schooling, and high amount of land, large herds or more years practicing sheep farming, GB middle age people in charge, higher schooling, intermediate amount of land, and intermediate herd size, GC (elderly people in charge, less schooling, low amount of land and reduced herd size, and GD (younger people in charge, high schooling, low amount of land, small herd size and less time performing the activity. Sheep farming was the first, second, and third productive option for 12%, 75% and 11,8% of producers. In some cases, sheep production in the region has been practiced for over 15 years; however it is the economic priority only of a small group of producers. Access to resources determined their level of development and lack of organization among sheep producers is evident.

  20. AGROECOSYSTEMS SUSTAINABILITY OF CASSAVA PRODUCTION OF PARAÍBA RURAL AREA FROM THE PERSPECTIVE OF BIOGRAM

    Directory of Open Access Journals (Sweden)

    Valdenildo Pedro da Silva

    2015-08-01

    Full Text Available Agriculture modernization resulting from green revolution occurred through means of diverse technological innovations as soluble fertilizers, pesticides, agricultural machinery and genetically modified seeds, aimed at increasing food production. However, the indiscriminate use of these innovations by farmers has been highlighted numerous environmental problems, affecting the productive agricultural system. This technological innovations reality and environmental obstacles, is also been experienced by cassava production in Paraíba rural area. Therefore, this study tried to assess the agroecosystems sustainability of cassava production (Manihot esculenta Crantz of Paraíba Rural Mesoregion, using Sustainable Development Index (S³ method, and its graphical representation, the Biogram. The results showed sustainability differences between the agroecosystems of investigated municipalities, of which Araçagi showed stable levels of sustainability, Araruna and Bananeiras demonstrated unstable levels, and Puxinanã showed the most critical sustainably level. It was concluded that, even the agroecosystems of Araçagi municipality showing better levels of sustainability, when compared with other municipalities assessed, cassava production showed unsustainability situations regarding its technological innovation levels, average yield of cassava production, land in erosion process, water scarcity and lack of social participation.

  1. Migrant farmers as information brokers: agroecosystem management in the transition zone of Ghana

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    Marney E. Isaac

    2014-06-01

    Full Text Available Environmentally induced farmer migration is an important livelihood strategy, yet little is known of the effects on the destination region agroecosystem information networks and management practices. In the forest-savanna transition zone (Brong Ahafo Region of Ghana, where migration from northern regions (migrant and from neighboring regions (settler is active, we chart the role of migrant famers and the type of agroecosystem management practices embedded in information networks using a social networks approach. Based on empirical network data from 44 respondents across three communities, we illustrate a diffuse information network, with variable tie frequency between settlement categories (local, settler, or migrant of farmers. The cohesion of this network is dependent on a few strategic bridging ties initiated by migrant farmers, who are thus centrally positioned to exchange agroecosystem management practices between geographically and socially distant groups. At the individual level, migrant and settler farmers are more likely: (1 to have larger networks with more ties between members of their networks, (2 to be brokers positioned between non-migrant farmers, and (3 to tend (although not statistically significantly to use pro-environmental management regimes, including agroforestry practices, new planting methods, and plot-scale weeding. We conceptualize this phenomenon as extended social and environmental experience and the deployment of social-ecological memory, with migrant farmers as potential agents of innovation and adaptive management.

  2. Landscape Diversity as a Screening Tool to Assess Agroecosystems Sustainability; Preliminary Study in Central Italy

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    Francesco Visicchio

    2007-06-01

    Full Text Available Modernization of agricultural activities has strongly modified agricultural landscapes. Intensive agriculture, with the increased use of inorganic fertiliser and density of livestock, affects water quality discharging nutrients such as nitrogen and phosphorus in water bodies. Nutrients in rivers, subsequently, are excellent indicators to assess sustainability/ land-use intensity in agroecosystems. Landscape, however, is a dynamic system and is the product of interaction amongst the natural environment and human activities, including farming which is a main driving force. At present not much has been investigated on the predictive role of landscape on land-use intensity. Aim of this study is to determine if, in Italian agroecosystem, landscape complexity can be related to land-use intensity. Indexes of landscape complexity (i.e. edge density, number of patches, Shannon’s diversity index, Interspersion-Juxtaposition index derived by processing Corine Land Cover data (level IV, 1:25.000 of Lazio Region, were related with landuse intensity (values of compounds of nitrogen and phosphorus and other parameters found in rivers monitored in accordance to European Directives on Waste Water. Results demonstrate that some landscape indexes were related to some environment parameters. Consequently landscape complexity, with further investigation, could be an efficient screening tool, at large scale, to assess water quality and ultimately agroecosystems sustainability in the absence of monitoring stations.

  3. Meteorological risks are drivers of environmental innovation in agro-ecosystem management

    Science.gov (United States)

    Gobin, Anne; Van de Vyver, Hans; Vanwindekens, Frédéric; Planchon, Viviane; Verspecht, Ann; Frutos de Cachorro, Julia; Buysse, Jeroen

    2016-04-01

    Extreme weather events such as droughts, heat waves and rain storms are projected to increase both in frequency and magnitude with climate change. The research hypothesis of the MERINOVA project is that meteorological risks act as drivers of environmental innovation in agro-ecosystem management which is being tested using a chain of risk approach. The project comprises of five major parts that reflect the chain of risks: the hazard, its impact on different agro-ecosystems, vulnerability, risk management and risk communication. Generalized Extreme Value (GEV) theory was used to model annual maxima of meteorological variables based on a location-, scale- and shape-parameter that determine the center of the distribution, the deviation of the location-parameter and the upper tail decay, respectively. Spatial interpolation of GEV-derived return levels has yielded maps of temperature extremes, precipitation deficits and wet periods. The degree of temporal overlap between extreme weather conditions and sensitive periods in the agro-ecosystem was determined using a bio-physically based modelling framework that couples phenological models, a soil water balance, crop growth and environmental models. 20-year return values for frost, heat stress, drought, waterlogging and field access during different crop stages were related to arable yields. The spatial extent of vulnerability is developed on different layers of spatial information that include inter alia meteorology, soil-landscapes, crop cover and management. The level of vulnerability and resilience of an agro-ecosystem is also determined by risk management. The types of agricultural risk and their relative importance differ across sectors and farm types as elucidated by questionnaires and focus groups. Risk types are distinguished according to production, market, institutional, financial and liability risks. A portfolio of potential strategies was identified at farm, market and policy level. In conclusion, MERINOVA

  4. The Platte River - High Plains Aquifer (PR-HPA) Long Term Agroecosystem Research (LTAR) Network - Data and Technological Resources to Address Current and Emerging Issues in Agroecosystems.

    Science.gov (United States)

    Okalebo, J. A.; Wienhold, B.; Suyker, A.; Erickson, G.; Hayes, M. J.; Awada, T.

    2015-12-01

    The Platte River - High Plains Aquifer (PR-HPA) is one of 18 established Long Term Agroecosystem Research (LTAR) networks across the US. PR-HPA is a partnership between the Institute of Agriculture and Natural Resources at the University of Nebraska-Lincoln (UNL), the USDA-ARS Agroecosystem Management Research Unit (AMRU) in Lincoln, and the USDA-ARS Environmental Management Research Unit (EMRU) in Clay Center, NE. The PR-HPA network encompasses 27,750 ha of research sites with data going back to the early 1900s. A partial list of on-going research projects include those encompassing long-term manuring and continuous corn (Est. 1912), dryland tillage plots (Est. 1970), soil nutrients and tillage (Est. 1983), biofuel feedstock studies (Est. 2001), and carbon sequestration study (Est. 2000). Affiliated partners include the National Drought Mitigation Center (NDMC) that develops measures to improve preparedness and adaptation to climate variability and drought; the High Plains Regional Climate Center (HPRCC) that coordinates data acquisition from over 170 automated weather stations and around 50 automated soil moisture network across NE and beyond; the AMERIFLUX and NEBFLUX networks that coordinate the water vapor and carbon dioxide flux measurements across NE with emphasis on rainfed and irrigated crop lands; the ARS Greenhouse gas Reduction through Agricultural Carbon Enhancement network (GRACEnet) and the Resilient Economic Agricultural Practices (REAP) project; and the Center for Advanced Land Management Information Technologies (CALMIT) that assists with the use of geospatial technologies for agriculture and natural resource applications. Current emphases are on addressing present-day and emerging issues related to profitability and sustainability of agroecosystems. The poster will highlight some of the ongoing and planned efforts in research pertaining to climate variability and change, water sustainability, and ecological and agronomic challenges associated

  5. Are carrots, corn and cattle really provided by Nature- If not, how can we appropriately identify the goods and services derived from agroecosystems?

    Science.gov (United States)

    People harbor different perspectives regarding the aspects of agroecosystems or cultivated lands that are or could be considered ecosystem services. The first issues that need to be addressed in this regard are to define agro-ecosystem services and to establish their potential p...

  6. Conservation in Brazil's Chocolate Forest: The Unlikely Persistence of the Traditional Cocoa Agroecosystem.

    Science.gov (United States)

    JOHNS

    1999-01-01

    / In southern Bahia, Brazil, the traditional cocoa agroecosystem with a dense shade canopy of native trees is now recognized as a secondary conservation route for highly endangered Atlantic Rainforest species. This "chocolate forest" of the densely shaded farms persists despite a massive 20-year Brazilian government modernization program in which shade was seen as a chief impediment to raising cocoa production. The objective of this study was to determine how this traditional agroecosystem endured. Although dense shade limits cocoa yield, it provides several agroecological benefits: control of insect pests and weeds, microclimate stability, and soil fertility maintenance. A keycomponent of modernization efforts was a shade-tree removal program designed to maximize cocoa production by using low shade and fertilizer while substituting agrochemicals for many beneficial roles of the overhead trees. This research found that many farmers rejected, or only partially accepted, the shade reduction process although it promised much higher cocoa yield and profit. Farmers employing a wide range of shading were interviewed, and it was found that decisions to remove or maintain the shade trees were linked to both agroecological and risk-minimization factors. Farmers' perceptions of the agroecological functions of the shade trees and individual willingness to entertain the economic risk associated with substituting agrochemicals for these were important. A less-profitable, but lower-risk approach of occasional fertilizer and agrochemical use with the traditional shade intact was a rational and widespread choice. Policies designed to maintain the traditional agroecosystem through the current economic crisis should heed the multiple functions of the overhead trees. KEY WORDS: Conservation; Brazil; Atlantic Rainforest; Cocoa; Agroecology; Risk; Agroforestry

  7. Action versus result-oriented schemes in a grassland agroecosystem: a dynamic modelling approach.

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    Rodolphe Sabatier

    Full Text Available Effects of agri-environment schemes (AES on biodiversity remain controversial. While most AES are action-oriented, result-oriented and habitat-oriented schemes have recently been proposed as a solution to improve AES efficiency. The objective of this study was to compare action-oriented, habitat-oriented and result-oriented schemes in terms of ecological and productive performance as well as in terms of management flexibility. We developed a dynamic modelling approach based on the viable control framework to carry out a long term assessment of the three schemes in a grassland agroecosystem. The model explicitly links grazed grassland dynamics to bird population dynamics. It is applied to lapwing conservation in wet grasslands in France. We ran the model to assess the three AES scenarios. The model revealed the grazing strategies respecting ecological and productive constraints specific to each scheme. Grazing strategies were assessed by both their ecological and productive performance. The viable control approach made it possible to obtain the whole set of viable grazing strategies and therefore to quantify the management flexibility of the grassland agroecosystem. Our results showed that habitat and result-oriented scenarios led to much higher ecological performance than the action-oriented one. Differences in both ecological and productive performance between the habitat and result-oriented scenarios were limited. Flexibility of the grassland agroecosystem in the result-oriented scenario was much higher than in that of habitat-oriented scenario. Our model confirms the higher flexibility as well as the better ecological and productive performance of result-oriented schemes. A larger use of result-oriented schemes in conservation may also allow farmers to adapt their management to local conditions and to climatic variations.

  8. Action versus result-oriented schemes in a grassland agroecosystem: a dynamic modelling approach.

    Science.gov (United States)

    Sabatier, Rodolphe; Doyen, Luc; Tichit, Muriel

    2012-01-01

    Effects of agri-environment schemes (AES) on biodiversity remain controversial. While most AES are action-oriented, result-oriented and habitat-oriented schemes have recently been proposed as a solution to improve AES efficiency. The objective of this study was to compare action-oriented, habitat-oriented and result-oriented schemes in terms of ecological and productive performance as well as in terms of management flexibility. We developed a dynamic modelling approach based on the viable control framework to carry out a long term assessment of the three schemes in a grassland agroecosystem. The model explicitly links grazed grassland dynamics to bird population dynamics. It is applied to lapwing conservation in wet grasslands in France. We ran the model to assess the three AES scenarios. The model revealed the grazing strategies respecting ecological and productive constraints specific to each scheme. Grazing strategies were assessed by both their ecological and productive performance. The viable control approach made it possible to obtain the whole set of viable grazing strategies and therefore to quantify the management flexibility of the grassland agroecosystem. Our results showed that habitat and result-oriented scenarios led to much higher ecological performance than the action-oriented one. Differences in both ecological and productive performance between the habitat and result-oriented scenarios were limited. Flexibility of the grassland agroecosystem in the result-oriented scenario was much higher than in that of habitat-oriented scenario. Our model confirms the higher flexibility as well as the better ecological and productive performance of result-oriented schemes. A larger use of result-oriented schemes in conservation may also allow farmers to adapt their management to local conditions and to climatic variations.

  9. Guava Waste to Sustain Guava (Psidium guajava) Agroecosystem: Nutrient "Balance" Concepts.

    Science.gov (United States)

    Souza, Henrique A; Parent, Serge-Étienne; Rozane, Danilo E; Amorim, Daniel A; Modesto, Viviane C; Natale, William; Parent, Leon E

    2016-01-01

    The Brazilian guava processing industry generates 5.5 M Mg guava waste year(-1) that could be recycled sustainably in guava agro-ecosystems as slow-release fertilizer. Our objectives were to elaborate nutrient budgets and to diagnose soil, foliar, and fruit nutrient balances in guava orchards fertilized with guava waste. We hypothesized that (1) guava waste are balanced fertilizer sources that can sustain crop yield and soil nutrient stocks, and (2) guava agroecosystems remain productive within narrow ranges of nutrient balances. A 6-year experiment was conducted in 8-year old guava orchard applying 0-9-18-27-36 Mg ha(-1) guava waste (dry mass basis) and the locally recommended mineral fertilization. Nutrient budgets were compiled as balance sheets. Foliar and fruit nutrient balances were computed as isometric log ratios to avoid data redundancy or resonance due to nutrient interactions and the closure to measurement unit. The N, P, and several other nutrients were applied in excess of crop removal while K was in deficit whatever the guava waste treatment. The foliar diagnostic accuracy reached 93% using isometric log ratios and knn classification, generating reliable foliar nutrient and concentration ranges at high yield level. The plant mined the soil K reserves without any significant effect on fruit yield and foliar nutrient balances involving K. High guava productivity can be reached at lower soil test K and P values than thought before. Parsimonious dosage of fresh guava waste should be supplemented with mineral K fertilizers to recycle guava waste sustainably in guava agroecosystems. Brazilian growers can benefit from this research by lowering soil test P and K threshold values to avoid over-fertilization and using fresh guava waste supplemented with mineral fertilizers, especially K. Because yield was negatively correlated with fruit acidity and Brix index, balanced plant nutrition and fertilization diagnosis will have to consider not only fruit yield

  10. Predicting the global warming potential of agro-ecosystems in Europe

    Science.gov (United States)

    Lehuger, S.; Gabrielle, B.; Chaumartin, F.

    2009-04-01

    Nitrous oxide, carbon dioxide and methane are the main biogenic greenhouse gases contributing to the global warming potential (GWP) of agro-ecosystems. Evaluating the impact of agriculture on climate requires a capacity to predict the net exchanges of these gases in an integrated manner, as related to pedo-climatic conditions and crop management. The biophysical crop model CERES-EGC is designed to predict the productivity and GWP of agro-ecosystems at the plot-scale. Here we applied a Bayesian calibration to its both sub-models of N2O emissions and CO2 fluxes to deal with parameterization and uncertainty analysis. The N2O emission module of CERES-EGC was calibrated against chamber measurements from 7 arable sites in France and the CO2 flux module was calibrated against eddy-covariance measurements from 3 sites in Europe. Measurements from the various sites were assimilated in the posterior probability density functions for the different parameters, using a Bayesian calibration method based on the Metropolis-Hastings algorithm. The model was subsequently extrapolated to predict CO2 and N2O fluxes over entire crop rotations of 3 European experimental sites of the NitroEurope-IP network. Indirect GHG emissions arising from the production of agricultural inputs and from cropping operations were also added to the final GWP. Such modelling approach makes it possible to test various agronomic management scenarios, in order to design productive agro-ecosystems with low global warming potential. The model would be extrapolated from plot- to regional-scale, with the ultimate goal of generating spatialized GHG inventories. Differentiating the emissions in space would thus make it possible to target critical zones in mitigation scenarios at regional scale.

  11. Socio-cultural and economic valuation of ecosystem services provided by Mediterranean mountain agroecosystems.

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    Alberto Bernués

    Full Text Available The aim of this work was to elucidate the socio-cultural and economic value of a number of ecosystem services delivered by mountain agroecosystems (mostly grazing systems in Euro-Mediterranean regions. We combined deliberative (focus groups and survey-based stated-preference methods (choice modelling to, first, identify the perceptions of farmers and other citizens on the most important ecosystem services and, second, to value these in economic terms according to the willingness to pay of the local (residents of the study area and general (region where the study area is located populations. Cultural services (particularly the aesthetic and recreational values of the landscape, supporting services (biodiversity maintenance and some regulating services (particularly fire risk prevention were clearly recognized by both farmers and citizens, with different degrees of importance according to their particular interests and objectives. The prevention of forest fires (≈50% of total willingness to pay was valued by the general population as a key ecosystem service delivered by these agroecosystems, followed by the production of specific quality products linked to the territory (≈20%, biodiversity (≈20% and cultural landscapes (≈10%. The value given by local residents to the last two ecosystem services differed considerably (≈10 and 25% for biodiversity and cultural landscape, respectively. The Total Economic Value of mountain agroecosystems was ≈120 € person(-1 year(-1, three times the current level of support of agro-environmental policies. By targeting and quantifying the environmental objectives of the European agri-environmental policy and compensating farmers for the public goods they deliver, the so-called "green" subsidies may become true Payments for Ecosystems Services.

  12. Socio-cultural and economic valuation of ecosystem services provided by Mediterranean mountain agroecosystems.

    Science.gov (United States)

    Bernués, Alberto; Rodríguez-Ortega, Tamara; Ripoll-Bosch, Raimon; Alfnes, Frode

    2014-01-01

    The aim of this work was to elucidate the socio-cultural and economic value of a number of ecosystem services delivered by mountain agroecosystems (mostly grazing systems) in Euro-Mediterranean regions. We combined deliberative (focus groups) and survey-based stated-preference methods (choice modelling) to, first, identify the perceptions of farmers and other citizens on the most important ecosystem services and, second, to value these in economic terms according to the willingness to pay of the local (residents of the study area) and general (region where the study area is located) populations. Cultural services (particularly the aesthetic and recreational values of the landscape), supporting services (biodiversity maintenance) and some regulating services (particularly fire risk prevention) were clearly recognized by both farmers and citizens, with different degrees of importance according to their particular interests and objectives. The prevention of forest fires (≈50% of total willingness to pay) was valued by the general population as a key ecosystem service delivered by these agroecosystems, followed by the production of specific quality products linked to the territory (≈20%), biodiversity (≈20%) and cultural landscapes (≈10%). The value given by local residents to the last two ecosystem services differed considerably (≈10 and 25% for biodiversity and cultural landscape, respectively). The Total Economic Value of mountain agroecosystems was ≈120 € person(-1) year(-1), three times the current level of support of agro-environmental policies. By targeting and quantifying the environmental objectives of the European agri-environmental policy and compensating farmers for the public goods they deliver, the so-called "green" subsidies may become true Payments for Ecosystems Services.

  13. Ecosystem service trade-offs, perceived drivers, and sustainability in contrasting agroecosystems in central Mexico

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    Carlos E. González-Esquivel

    2015-03-01

    Full Text Available The ability of agroecosystems to provide food ultimately depends on the regulating and supporting ecosystem services that underpin their functioning, such as the regulation of soil quality, water quality, soil erosion, pests, and pollinators. However, there are trade-offs between provisioning and regulating or supporting services, whose nature at the farm and plot scales is poorly understood. We analyzed data at the farm level for two agroecosystems with contrasting objectives in central Mexico: one aimed at staple crop production for self-subsistence and local markets, the other directed to a cash crop for export markets. Bivariate and multivariate trade-offs were analyzed for different crop management strategies (conventional, organic, traditional, crop rotation and their underpinning socioeconomic drivers. There was a clear trade-off between crop yield and soil quality in self-subsistence systems. However, other expected trade-offs between yields and soil quality did not always occur, likely because of the overall good soils of the region and the low to medium input profile of most farms. Trade-offs were highly dependent on farm-specific agricultural practices; organic, traditional, and rotation management systems generally showed smaller trade-offs between yield and soil quality, pest control, and biodiversity than did conventional management systems. Perceived drivers reported by farmers included increasing prices for cash crops, rising costs of inputs, and extreme climatic events (e.g., drought, hail, frost. Farmers did not identify the regulation of soil quality, water quality, soil erosion, pests, or pollinators as important constraints. Although acceptable yields could be maintained irrespective of key regulating and supporting services according to these perceptions, current levels of soil erosion and nutrient runoff are likely to have important negative effects at the watershed scale. Sustainability in both agroecosystems could be

  14. Characteristics of pristine volcanic materials: Beneficial and harmful effects and their management for restoration of agroecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Anda, Markus, E-mail: markusandas@yahoo.com; Suparto; Sukarman

    2016-02-01

    Eruption of Sinabung volcano in Indonesia began again in 2010 after resting for 1200 years. The volcano is daily emitting ash and pyroclastic materials since September 2013 to the present, damaging agroecosystems and costing for management restoration. The objective of the study was to assess properties and impacts of pristine volcanic material depositions on soil properties and to provide management options for restoring the affected agroecosytem. Land satellite imagery was used for field studies to observe the distribution, thickness and properties of ashfall deposition. The pristine ashfall deposits and the underlying soils were sampled for mineralogical, soluble salt, chemical, physical and toxic compound analyses. Results showed that uneven distribution of rainfall at the time of violent eruption caused the areas receiving mud ashfall developed surface encrustation, which was not occur in areas receiving dry ashfall. Ashfall damaged the agroecosytem by burning vegetation, forming surface crusts, and creating soil acidity and toxicity. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses of encrustated layer indicated the presence of gypsum and jarosite minerals. Gypsum likely acted as a cementing agent in the formation of the encrustation layer with extremely low pH (2.9) and extremely high concentrations of Al, Ca and S. Encrustation is responsible for limited water infiltration and root penetration, while the extremely high concentration of Al is responsible for crop toxicity. Mud ashfall and dry ashfall deposits also greatly changed the underlying soil properties by decreasing soil pH and cation exchange capacity and by increasing exchangeable Ca, Al, and S availability. Despite damaging vegetation in the short-term, the volcanic ashfall enriched the soil in the longer term by adding nutrients like Ca, Mg, K, Na, P, Si and S. Suggested management practices to help restore the agroecosystem after volcanic eruptions include: (i) the

  15. Predictors of leafhopper abundance and richness in a coffee agroecosystem in Chiapas, Mexico.

    Science.gov (United States)

    Burdine, Justin D; Domínguez Martínez, Gabriel H; Philpott, Stacy M

    2014-04-01

    Coffee agroecosystems with a vegetatively complex shade canopy contain high levels of biodiversity. However, as coffee management is intensified, diversity may be lost. Most biodiversity studies in coffee agroecosystems have examined predators and not herbivores, despite their importance as potential coffee pests and coffee disease vectors. We sampled one abundant herbivore group of leafhoppers on an organic coffee farm in Chiapas, Mexico. We sampled leafhoppers with elevated pan traps in high- and moderate-shade coffee during the dry and wet seasons of 2011. The two major objectives were to 1) compare leafhopper abundance and richness during the wet and dry seasons and 2) examine the correlations between habitat characteristics (e.g., vegetation, elevation, and presence of aggressive ants) and leafhopper richness and abundance. We collected 2,351 leafhoppers, representing eight tribes and 64 morphospecies. Leafhopper abundance was higher in the dry season than in the wet season. Likewise, leafhopper richness was higher in the dry season. Several vegetation and other habitat characteristics correlated with abundance and richness of leafhoppers. The number of Inga trees positively correlated with leafhopper abundance, and other significant correlates of abundance included vegetation complexity. Leafhopper richness was correlated with the number of Inga trees. As leafhoppers transmit important coffee diseases, understanding the specific habitat factors correlating with changes in abundance and richness may help predict future disease outbreaks.

  16. Spatial and Temporal Variability of N, P and K Balances for Agroecosystems in China

    Institute of Scientific and Technical Information of China (English)

    SHEN Run-Ping; SUN Bo; ZHAO Qi-Guo

    2005-01-01

    Nitrogen, phosphorus, and potassium balances for agroecosystems in China from 1993 to 2001 were calculated at national and provincial levels using statistical data and related parameters, and their spatial and temporal variabilities were analyzed with GIS to estimate the potential impacts of nutrient N, P and K surpluses or deficits to soil, water and air. At the national scale, the N and P balances from 1993 to 2001 showed a surplus, with the nitrogen surplus remaining relatively stable from 1997-2001. Although during this period the P surplus pattern was similar to N, it had smaller values and kept increasing as the use of phosphate fertilizer increased year by year. However, K was deficient from 1993 to 2001 even though from 1999 to 2001 the K deficit decreased. The spatial analysis revealed higher N surpluses in the more developed southeastern provinces and lowest in the western and northern provinces where there was less chemical fertilizer input. The serious K deficit mainly occurred in Shanghai and Beijing municipalities, Jiangsu, Zhejiang and Hubei provinces, and Xinjiang autonomous regions. For the years 1992, 1996 and 2001, N surpluses and K deficits had significant positive spatial correlations with per capita gross domestic product (GDP), per capita gross industrial output value, and per capita net income of rural households. This showed that the level of economic development played an important role on nutrient balances in the agroecosystems.

  17. Assessment of Groundwater Quality of Selected Inland Valley Agro-ecosystems for Irrigation in Southwest Nigeria

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    Olatunji S Aboyeji

    2015-10-01

    Full Text Available The study assessed the quality of groundwater of 6 inland valley (IV agro-ecosystems with a view to establishing their characteristics for cropping in the derived savannah of southwest Nigeria. Water samples were collected in piezometers during the rainy and dry seasons and analysed for physicochemical and heavy metal properties. Major water quality indices and comparison with stipulated standards were used to determine the usability of the waters for irrigation. The study showed that the waters were generally neutral to slightly alkaline, with the dominance structure of the major cations and anions in the order of Na+ > Ca2+ > K+ > Mg2+ and Cl- > SO42- > HCO3- > CO3. The concentration of heavy metals was generally within the recommended limits for most crops grown in the study area. Major water quality indices (sodium adsorption ratio, soluble sodium percentage, total dissolved solids, permeability index, magnesium adsorption ratio, Kelly’s ratio and residual sodium bicarbonate are generally within the levels acceptable for crop irrigation. Kruskal-Wallis H test (two-tailed showed that there was no statistically significant difference in the water quality parameters/indices between the inland valley sites, P = 0.935. The groundwater of inland valley agro-ecosystems of the study area is generally suitable for agricultural utilisation.DOI: http://dx.doi.org/10.5755/j01.erem.71.2.10802

  18. Species Richness, Community Organization, and Spatiotemporal Distribution of Earthworms in the Pineapple Agroecosystems of Tripura, India

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    Animesh Dey

    2016-01-01

    Full Text Available The impact that plant communities may have on underground faunal diversity is unclear. Therefore, understanding the links between plants and organisms is of major interest. Earthworm population dynamics were studied in the pineapple agroecosystems of Tripura to evaluate the impact of monoculture plantation on earthworm communities. A total of thirteen earthworm species belonging to four families and five genera were collected from different sampling sites. Application of sample-based rarefaction curve and nonparametric richness estimators reveal 90–95% completeness of sampling. Earthworm community of pineapple agroecosystems was dominated by endogeic earthworms and Drawida assamensis was the dominant species with respect to its density, biomass, and relative abundance. Vertical distribution of earthworms was greatly influenced by seasonal variations. Population density and biomass of earthworms peaked during monsoon and postmonsoon period, respectively. Overall density and biomass of earthworms were in increasing trend with an increase in plantation age and were highest in the 30–35-year-old plantation. Significant decrease in the Shannon diversity and evenness index and increase in Simpson’s dominance and spatial aggregation index with an increase in the age of pineapple plantation were recorded. Soil temperature and soil moisture were identified as the most potent regulators of earthworm distribution in the pineapple plantation.

  19. Irrigation and Maize Cultivation Erode Plant Diversity Within Crops in Mediterranean Dry Cereal Agro-Ecosystems

    Science.gov (United States)

    Fagúndez, Jaime; Olea, Pedro P.; Tejedo, Pablo; Mateo-Tomás, Patricia; Gómez, David

    2016-07-01

    The intensification of agriculture has increased production at the cost of environment and biodiversity worldwide. To increase crop yield in dry cereal systems, vast farmland areas of high conservation value are being converted into irrigation, especially in Mediterranean countries. We analyze the effect of irrigation-driven changes on the farm biota by comparing species diversity, community composition, and species traits of arable plants within crop fields from two contrasting farming systems (dry and irrigated) in Spain. We sampled plant species within 80 fields of dry wheat, irrigated wheat, and maize (only cultivated under irrigation). Wheat crops held higher landscape and per field species richness, and beta diversity than maize. Within the same type of crop, irrigated wheat hosted lower plant diversity than dry wheat at both field and landscape scales. Floristic composition differed between crop types, with higher frequencies of perennials, cosmopolitan, exotic, wind-pollinated and C4 species in maize. Our results suggest that irrigation projects, that transform large areas of dry cereal agro-ecosystems into irrigated crop systems dominated by maize, erode plant diversity. An adequate planning on the type and proportion of crops used in the irrigated agro-ecosystems is needed in order to balance agriculture production and biodiversity conservation.

  20. Comparison of Soil Biota Between Organic and Conventional Agroecosystems in Oregon, USA

    Institute of Scientific and Technical Information of China (English)

    WU Shan-Mei; HU Dun-Xiao; E. R. INGHAM

    2005-01-01

    Soil samples at 0-10 cm in depth were collected periodically at paired fields in Corvallis, Oregon, USA to compare differences in soil microbial and faunal populations between organic and conventional agroecosystems. Results showed that the organic soil ecosystem had a significantly higher (P < 0.05) average number or biomass of soil bacteria; densities of flagellates, amoebae of protozoa; some nematodes, such as microbivorous and predaceous nematodes and plant-parasitic nematodes; as well as Collembola. Greater numbers of Rhabditida (such as Rhabditis spp.), were present in the organic soil ecosystem while Panagrolaimus spp. were predominant in the conventional soil ecosystem. The omnivores and predators of Acarina in the Mesostigmata (such as Digamasellidae and Laelapid), and Prostigmata (such as Alicorhaiidae and Rhagidiidae), were also more abundant in the organic soil ecosystem. However, fungivorous Prostigmata (such as Terpnacaridae and Nanorchestidae) and Astigmata (such as Acarida) were significantly higher (P < 0.05) in the conventional soil ecosystem, which supported the finding that total fungal biomass was greater in the conventional soil ecosystem. Seansonal variations of the population depended mostly on soil moisture condition and food web relationship.The population declined from May to October for both agroecosystems. However, higher diversities and densities of soil biota survived occurred in the organic soil ecosystem in the dry season.

  1. Legume Nodulating Bacterium, Achromobacter xylosoxidans Found in Tropical Shrub Agroecosystem, Sumatera, Indonesia

    Directory of Open Access Journals (Sweden)

    Sri Wedhastri

    2015-11-01

    Full Text Available Legume nodulating bacteria (LNB, known also as rhizobia, are soil bacteria, which are able to form rootnodules and fi x nitrogen in the leguminous plants. The LNB availability in the soil depends on the type ofagroecosystem, where plant grows. In this study, we isolated LNB from the shrub agroecosystem in Sumatera,Indonesia, and obtained four selected bacterial strains. Among them, the isolate UGM48a formed root nodulein Macroptilium atropurpureum and showed highest number of nitrogenase activity. UGM48a also contains nifHand nodA genes. An analysis of the PCR-amplifi ed 16S rDNA and BLASTn analysis showed that UGM48adisplayed 96% similarity with Achromobacter xylosoxidans. In addition, UGM48a were successfully nodulatedGlycine max (L. merr var. wilis. This is the fi rst report detecting A. xylosoxidans as nodule-forming species forGlycine max possesing the positive copy of nodA gene.Keywords : Legume Nodulating Bacteria, shrub agroecosystem, Achromobacter xylosoxidans, nodA, Glycine max

  2. Energetic efficiency of agroecosystems as an indicator of sustainability; Eficiencia energetica de agroecossistemas como indicador de sustentabilidade

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, Osmar de Carvalho [Universidade Estadual Paulista Julio de Mesquita Filho (FCA/UNESP), Botucatu, SP (Brazil). Fac. de Ciencias Agronomicas; Colen, Fernando [Universidade Federal de Minas Gerais (ICA/UFMG), Montes Claros, MG (Brazil). Inst. de Ciencias Agrarias; Campos, Alessandro Torres [Universidade Federal de Lavras (DEG/UFLA), MG (Brazil). Dept. de Engenharia

    2010-07-01

    The dependence of modern agriculture in relation to non-renewable energy sources became more pronounced over time. The intensive use of non-renewable energy in agroecosystems, especially fossil fuels, increased the physical output of food and raw materials, reducing the painfulness of work and the improvement of income in the sector. However, complex problems brought individually or in jail, which transformed human life in terms of ecological, social and economic development. It should build indexes in order to relate the inputs and outputs of energy in ecosystems. A breakthrough in the relationship between sustainability and energy analysis of farms is the use of energy efficiency index, the relationship between outputs and inputs of non-renewable energy in agroecosystems. This paper aims to present the energy efficiency of different agroecosystems. The results demonstrate the dependence of agroecosystems in relation to fossil energy sources. It was concluded that it is necessary to make efficient use of exhaustible natural resources, particularly fossil fuels. (author)

  3. Sustainability indicators, alternative strategies and trade-offs in peasant agroecosystems : analysing 15 case studies from Latin America

    NARCIS (Netherlands)

    Astier, M.; Speelman, E.N.; López-Ridaura, S.; Masera, O.R.; Gonzalez-Esquivel, C.E.

    2011-01-01

    In view of the urgent need to improve agroecosystem sustainability, several efforts have been made to evaluate the effect of alternative strategies on key environmental and socioeconomic variables at the farm, community and regional levels. Most peasant farmers manage complex and diverse agroecosyst

  4. Heavy-metal Balances, Part II. Management of cadmium, copper, lead, and zinc in European Agro-Ecosystems

    NARCIS (Netherlands)

    Moolenaar, S.W.

    2000-01-01

    The aim of sustainable heavy-metal management in agro-ecosystems is to ensure that the soil continues to fulfill its functions: in agricultural production, in environmental processes such as the cycling of elements, and as a habitat of numerous organisms. To understand and manage heavy-metal flows e

  5. Agrodiversity v.2: An educational simulation tool to address some challenges for sustaining functional agrodiversity in agro-ecosystems

    NARCIS (Netherlands)

    Speelman, E.N.; Garcia-Barrios, L.E.

    2010-01-01

    Functional agrodiversity can be useful and even essential for, i.e., the long-term sustainability of agriculture. However, still many aspects of this concept are not well understood. The interplay between species in diverse agro-ecosystems is based on processes as, i.e., competition, facilitation, a

  6. Productivity, Respiration, and Light-Response Parameters of World Grassland and Agroecosystems Derived From Flux-Tower Measurements

    NARCIS (Netherlands)

    Gilmanov, T.G.; Aires, L.; Barsca, V.; Baron, S.; Moors, E.J.; Jacobs, A.

    2010-01-01

    Grasslands and agroecosystems occupy one-third of the terrestrial area, but their contribution to the global carbon cycle remains uncertain. We used a set of 316 site-years of CO2 exchange measurements to quantify gross primary productivity, respiration, and light-response parameters of grasslands,

  7. Structural and Functional Diversity of Weed Species in Organic and Conventional Rice Agro-Ecosystems

    Directory of Open Access Journals (Sweden)

    S. Y. Mousawi Toghani

    2016-02-01

    Full Text Available Introduction Diversity reflects the complexity of a system and can maintain its sustainability. Higherdiversity, results in higher inherent complexity of agro-ecosystems and strengthen their processes. It is necessary to realize the spatial distribution and temporal properties of the biodiversity components in agro-ecosystems, for the conservation and optimal utilization. Since weeds as a complementary component of agro-ecosystems and are inseparable, so the study of species, their functional and structural diversity of them can play an important role in weed management and balance in ecological systems. Materials and Methods This study was performed to determine the effects of different management systems on structural, and functional diversity of paddy weeds in Mazandaran province. Three rice fields, ranged from 0.3 to 0.5 ha, were chosen for each management system. Samples were collected from three fields running under each selected management system (organic and conventional. Data (number of weed species and their density were randomly gathered from 9 quadrates (1m×1m per each field in four stages (tillering, stem elongation, grain filling and after harvest. The diversity, evenness, frequency and similarity indices for weeds were determined at genera and species level. Data analysis carried out through T-test and grouping performed via cluster analysis as hierarchy. Results and Discussion All monitored weeds can be classified into four plant family including cereals (Poaceae, sedges (Cyperaceae, plantain (Plantaginaceae and chicory (Asteraceae.Under conventional systems the values of weed diversity indices were higher during tillering and stem elongation compared with organic ones, and were lower during grain filling and after harvest stages. However indices of weed evenness showed contrary tendency. Both Sympson and Shanon-Wiener diversity indices, consist of two clusters in 76% similarity. Evenness indices of Kamargo and Smith

  8. Food resource and temporal partitioning amongst a guild of predatory agroecosystem-inhabiting ant species

    Institute of Scientific and Technical Information of China (English)

    Vivek Mohan AGARWAL; Neelkamal RASTOGI

    2009-01-01

    Prey diversity and temporal foraging patterns of six abundant, predatory ant species were investigated seasonally in an ngroeeosystem with two main vegetable crops. Pheidole sp. demonstrated the highest predation success and therefore appears to be the dominant species while Tapinoma melanocephalum showed the lowest success under the natural field conditions. Investigation of prey diversity and temporal activity patterns with the null model tests of niche overlap revealed a significant overlap indicating that the activity periods and prey diversity may not be solely influenced by interactions among the co-existing ant species. However, niche partitioning in the daily peak activity periods was demonstrated during all the three seasons (summer, rainy and winter) particularly between Pheidole sp. and T. melanocephalum. Pheidole sp. exhibited a high intensity, broadly extended mono-modal foraging pattern. Camponotus compressus and C. paria showed bi-modality in their foraging activity during the rainy season and mono-modal patterns during summer and winter seasons. Pachycondyla tesserinoda, Tetramorium sp. and T. melanocephalum exhibited peak foraging activities in the morning hours during the summer and rainy seasons. The activity profiles of C. compressus and T. melanocephalum were skewed towards late afternoon hours during the winter season indicating avoidance of foraging activity during the favourable periods when the more aggressive Phe/do/e sp. is active. In the sponge gourd agroecosystem, the ants captured predominantly hymenopteran, orthopteran and eoleopteran insects. While Pheidole sp. hunted mainly the large orthopteran prey, other ant species captured worker ants in the sponge gourd ngroeeosystem. In the cauliflower ngroecosystem, while other species captured prey chiefly belonging to six orders, i. e., Lepidoptera, Hymenoptera, Coleoptera, Hemiptera, Isoptera and Diptera, Pheidole sp. and P. tesserinoda were the only species to also hunt many orthopteran

  9. Energy consumption, greenhouse gas emissions and assessment of sustainability index in corn agroecosystems of Iran

    Energy Technology Data Exchange (ETDEWEB)

    Yousefi, Mohammad, E-mail: m.yousefi@pgs.razi.ac.ir [Department of Agronomy and Plant Breeding, Campus of Agriculture and Natural Resources, Razi University, Kermanshah (Iran, Islamic Republic of); Damghani, Abdolmajid Mahdavi [Departments of Agroecology, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Khoramivafa, Mahmud [Department of Agronomy and Plant Breeding, Campus of Agriculture and Natural Resources, Razi University, Kermanshah (Iran, Islamic Republic of)

    2014-09-15

    The objectives of this study were to assess the energy flow, greenhouse gas (GHG) emission, global warming potential (GWP) and sustainability of corn production systems in Kermanshah province, western Iran. The data were collected from 70 corn agroecosystems which were selected based on randomly sampled method in the summer of 2011. The results indicated that total input and output energy were 50,485 and 134,946 MJ ha{sup −1}, respectively. The highest share of total input energy in corn production systems was recorded for N fertilizer, electricity power and diesel fuel with 35, 25 and 20%, respectively. Energy use efficiency and energy productivity were 2.67 and 0.18 kg MJ{sup −1}, respectively. Also agrochemical energy ratio was estimated as 40%. Applying chemical inputs produced the following emissions of greenhouse gases: 2994.66 kg CO{sub 2,} 31.58 kg N{sub 2}O and 3.82 kg CH{sub 4} per hectare{sub .} Hence, total GWP was 12,864.84 kg Co{sub 2}eq ha{sup −1} in corn production systems. In terms of CO{sub 2} equivalents 23% of the GWPs came from CO{sub 2}, 76% from N{sub 2}O, and 1% from CH{sub 4}. In this study input and output C equivalents per total GHG and Biomass production were 3508.59 and 10,696.34 kg C ha{sup −1}. Net carbon and sustainability indexes in corn production systems were 7187.75 kg C ha{sup −1} and 2.05. Accordingly, efficient use of energy is essential to reduce the greenhouse gas emissions and environmental impact in corn agroecosystems. - Highlights: • Increasing of energy consumption leaded to decreasing energy use efficiency in corn agroecosystems. • Total greenhouse gas (GHG) emission as CO{sub 2}, N{sub 2}O and CH{sub 4} in corn production systems were 2994.66, 31.58 and 3.82 kg ha{sup -1}, respectively. • Global warming potential (GWP) was 12864.84 kg CO{sub 2}eq ha{sup -1} in corn production systems. • Sustainability index in corn production systems was 2.05. • Reducing use of chemicals fertilizer and diesel fuel

  10. Considerations in miniaturizing simplified agro-ecosystems for advanced life support

    Science.gov (United States)

    Volk, T.

    1996-01-01

    Miniaturizing the Earth's biogeochemical cycles to support human life during future space missions is the goal of the NASA research and engineering program in advanced life support. Mission requirements to reduce mass, volume, and power have focused efforts on (1) a maximally simplified agro-ecosystem of humans, food crops, and microbes; and, (2) a design for optimized productivity of food crops with high light levels over long days, with hydroponics, with elevated carbon dioxide and other controlled environmental factors, as well as with genetic selection for desirable crop properties. Mathematical modeling contributes to the goals by establishing trade-offs, by analyzing the growth and development of experimental crops, and by pointing to the possibilities of directed phasic control using modified field crop models to increase the harvest index.

  11. Nutrient Cycling and Balance in Red Soil Agroecosystem and Their Management

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An experiment was conducted in a red soil derived from Quaternary red clay in the Ecological Experiment Station of Red Soil, the Chinese Academy of Sciences, located in Yingtan (28°15' 30" N, 116°55' 30" E), Jiangxi Province. The results show that the major ways of nutrient loss are leaching and nitrogen volatilization. Rationalizing crop distribution, stimulating nutrient recycling, and improving internal nutrient flow are effective measures to decrease nutrient loss and to promote nutrient utilization efficiency. The important ways of regulating nutrient cycling and balance in the agroecosystem of the red soil are to establish optimal eco-agricultural models, practice balanced fertilization and combine the cropping system with the livestock system.

  12. AGRO-ECOSYSTEMS AND SUSTAINABLE DEVELOPMENT OF WATER RESOURCES IN ARGES RIVER BASIN

    Directory of Open Access Journals (Sweden)

    Tatiana Diaconu

    2010-01-01

    Full Text Available Lotic ecosystems, part of the Natural Capital, is one of the key factors functioning of socio - economic development andtheir support. An important role in their sustainable development, is the retention and recycling of nutrients, especiallyN, P and their compounds. The nutrients in lotic and lentic ecosystems are either due to natural biochemical processesor by human impact of pollution or broadcast process and characterize the ecological status of water bodies and thuscan determine the quality of services provided. A special importance have agro-ecosystems, particularly multifunctionallivestock farms. Pathways by which pollutants (especially nutrients and pesticides, and other pollutants to reach bodiesof water are different (surface drainage, percolation, etc..To ensure sustainable development of water resources is necessary for agricultural development to take place in termsof minimizing waste streams and not affect the production and support of NC.

  13. Advances in Nitrogen Denitrification and N2O Emission in Agro-ecosystem

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-shu; DING Hong; QIN Sheng-jin

    2011-01-01

    Nitrification and denitrification are two key links of nitrogen flow cycle in soil. N2O and N2, generated from biochemical process of nitrogen, can cause not only the nitrogen losses and reduction of nitrogen use efficiency, but also the boosted concentration of greenhouse gases,severely endangering the environment. Accordingly, nitrification-denitrification has been more and more concerned from whether an agricultural view, or an environmental one. Referring to the related literatures published at home and abroad in recent years, we overviewed the denitrification-caused N loss and N2O emission in various agro-ecosystems, and based on which we put forward countermeasures to reduce the denitrification-caused N loss and N2O emission and its research prospects in the future.

  14. Emergy signature as a basis for sustainability valuation of agro-ecosystems

    DEFF Research Database (Denmark)

    Ghaley, Bhim Bahadur; Montesino San Martin, Manuel; Porter, John Roy

    sustainability of the agricultural practice. The emergy analysis is an accounting tool which takes into account both the environment and the economic costs of the production system, based on principles of thermodynamics. Here the objective of the study is the evaluation of a novel organically based, food...... and energy production (CFE) system to assess the resource use efficiency compared to conventional intensive winter wheat production system in Demark by using Emergy analysis (Odum and Odum, 2000). The emergy analysis was carried out by taking into account the inflow and the outflows of emergy within...... the boundaries of the production systems and calculating the emergy indices. The results reveal that the innovative agroecosystems, exemplified by CFE, are less resources demanding and amenable to local environments and helps conserve the ecosystem services in terms of sustainable supply of soil nutrients...

  15. A multivariate analysis for evaluating the environmental and economical aspects of agroecosystem sustainability in central Italy.

    Science.gov (United States)

    Di Felice, Vincenzo; Mancinelli, Roberto; Proulx, Raphaël; Campiglia, Enio

    2012-05-15

    Over the past century farming activity has intensified worldwide, characterized by an increasing dependence on external inputs and on land conversion. Although the intensification of agriculture has increased productivity, the sustainability of agroecosystems has also been compromised. The objective of this study is to build multivariate relationships between farm structural characteristics and farm performance to highlight the relative costs and benefits of four main farming systems in Central Italy: organic, conventional, mixed and non-mixed farms. Results show that the relationship between cropping diversity and agroecological sustainability is associated to a mixed versus non-mixed farm management dichotomy, not to organic or conventional farming practices. The presence of livestock appears to have played an important role as an economic lever for diversifying the farm cropping system.

  16. Use of N immobilization to tighten the N cycle in conventional agroecosystems.

    Science.gov (United States)

    McSwiney, Claire P; Snapp, Sieglinde S; Gentry, Lowell E

    2010-04-01

    Soils in conventional agroecosystems are purposely held in a nitrogen (N)-saturated state to maximize crop yields. Planting winter annual cover crops when fields are usually fallow has been proposed to ameliorate N losses from soils. In this study we introduced winter annual cover crops into an N rate study with plots fertilized at 0, 34, 67, 101, 134, 168, and 202 kg N/ha in maize (Zea mays L.) to determine how winter annual cover crops affect yields, N2O and NO3- fluxes, and N pools. At the six-leaf stage and during flowering, incorporation of cover crop into soil resulted in a 30% reduction in maize biomass. Three weeks after fertilization, KCl-extractable soil mineral N was 75-87% lower in covercropped soils than in no-cover soils, indicating that N had been immobilized in the covercropped soils. At physiological maturity, there was no difference between cover and no-cover treatments in crop yield, which was maximized at 9 Mg/ha in 2006 and 7 Mg/ha in 2007. Where N rates exceed crop requirements, cover crop incorporation may reduce N exports as NO3- and N2O. Tighter N cycling in conventional agroecosystems could be fostered by matching N rates to the amount of N removed with grain and using N immobilization to retain N and support yields. If N immobilization is viewed as a means for efficient fertilizer N use rather than a process that decreases crop productivity, growers might be more willing to adopt cover-cropping practices.

  17. Challenges in the Measurement of Antibiotics and in Evaluating Their Impacts in Agroecosystems: A Critical Review.

    Science.gov (United States)

    Aga, Diana S; Lenczewski, Melissa; Snow, Daniel; Muurinen, Johanna; Sallach, J Brett; Wallace, Joshua S

    2016-03-01

    Large quantities of antibiotics are used in agricultural production, resulting in their release to agroecosystems through numerous pathways, including land application of contaminated manure, runoff from manure-fertilized fields, and wastewater irrigation of croplands. Antibiotics and their transformation products (TPs) exhibit a wide range of physico-chemical and biological properties and thus present substantive analytical challenges. Advances in the measurement of these compounds in various environmental compartments (plants, manure, soil, sediment, and water) have uncovered a previously unrealized landscape of antibiotic residues. These advanced multiresidue methods, designed to measure sub-ng g concentrations in complex mixtures, remain limited by the inherent intricacy of the sample matrices and the difficultly in eliminating interferences that affect antibiotic detection. While efficient extraction methods combined with high sensitivity analysis by liquid chromatography/mass spectrometry can provide accurate quantification of antibiotics and their TPs, measured concentrations do not necessarily reflect their bioavailable fractions and effects in the environment. Consequently, there is a need to complement chemical analysis with biological assays that can provide information on bioavailability, biological activity, and effects of mixtures. Enzyme-linked immunosorbent assays (ELISA), often used as screening tools for antibiotic residues, may be useful for detecting the presence of structurally related antibiotic mixtures but not their effects. Other tools, including bioreporter assays, hold promise in measuring bioavailable antibiotics and could provide insights on their biological activity. Improved assessment of the ecological and human health risks associated with antibiotics in agroecosystems requires continued advances in analytical accuracy and sensitivity through improvements in sample preparation, instrumentation, and screening technologies.

  18. Bacteria isolated from a sugarcane agroecosystem: their potential production of polyhydroxyalcanoates and resistance to antibiotics

    Directory of Open Access Journals (Sweden)

    Lima Teresa Cristina S. de

    1999-01-01

    Full Text Available In this investigation, a sugarcane agroecosystem at a coastal tableland, in the northeast of Brazil, was screened to obtain bacteria strains able to synthesize poly-b-hydroxyalkanoates (PHA, using sucrose as the main carbon source. The potential to synthesize PHA was tested qualitatively by Sudan Black staining of colonies growing in different carbon sources: sucrose, glucose, fructose, propionate and cellulose. In a typical sugarcane crop management system, the plantation is burned before harvesting and vinasse, a byproduct of alcohol production, is used in a fertirrigation system causing, probably, selective pressures on the microbiota of natural environments. Eightytwo bacteria strains, belonging to 16 different genera and 35 different species, were isolated. The data showed that 11 strains (ca 13%, nine of which belonging to the genus Pseudomonas, presented a strong Sudan Black staining in several carbon sources tested and, simultaneously, showed multiple resistance to antibiotics. Resistance to antibiotics is an advantageous feature for the biotechnological production of PHAs. The total number of isolates with multiple resistance to antibiotics was 73, and 38% of them belong to the genus Pseudomonas. Among the isolates, ca 86% and 43% grew in the presence of 10-100 U/ml of penicillin and/or 100-300 mg/ml of virginiamycin, respectively. These antibiotics are utilized in the alcohol distillery we investigated. The results suggest that some agroecosystem environments could be considered as habitats where bacteria are submitted to nutritional unbalanced conditions, resulting in strains with potential ability to produce PHAs, and also, to an increase in the microbial diversity.

  19. Energy consumption, greenhouse gas emissions and assessment of sustainability index in corn agroecosystems of Iran.

    Science.gov (United States)

    Yousefi, Mohammad; Damghani, Abdolmajid Mahdavi; Khoramivafa, Mahmud

    2014-09-15

    The objectives of this study were to assess the energy flow, greenhouse gas (GHG) emission, global warming potential (GWP) and sustainability of corn production systems in Kermanshah province, western Iran. The data were collected from 70 corn agroecosystems which were selected based on randomly sampled method in the summer of 2011. The results indicated that total input and output energy were 50,485 and 134,946 MJ ha(-1), respectively. The highest share of total input energy in corn production systems was recorded for N fertilizer, electricity power and diesel fuel with 35, 25 and 20%, respectively. Energy use efficiency and energy productivity were 2.67 and 0.18 kg MJ(-1), respectively. Also agrochemical energy ratio was estimated as 40%. Applying chemical inputs produced the following emissions of greenhouse gases: 2994.66 kg CO2, 31.58 kg N2O and 3.82 kg CH4 per hectare. Hence, total GWP was 12,864.84 kg Co2eq ha(-1) in corn production systems. In terms of CO2 equivalents 23% of the GWPs came from CO2, 76% from N2O, and 1% from CH4. In this study input and output C equivalents per total GHG and Biomass production were 3508.59 and 10,696.34 kg Cha(-1). Net carbon and sustainability indexes in corn production systems were 7187.75 kg Cha(-1) and 2.05. Accordingly, efficient use of energy is essential to reduce the greenhouse gas emissions and environmental impact in corn agroecosystems.

  20. Assessment of alternative management practices and policies affecting soil carbon in agroecosystems of the central United States

    Energy Technology Data Exchange (ETDEWEB)

    Donigian, A.S.; Barnwell, T.O.; Jackson, R.B.; Patwardhan, A.S.; Weinrich, K.B.

    1994-04-01

    The goal of the U.S. EPA BIOME Agroecosystems Assessment Project is to evaluate the degree to which agroecosystems can be technically managed, on a sustainable basis, to conserve and sequester carbon, reduce the accumulation of carbon dioxide in the atmosphere, and provide reference datasets and methodologies for agricultural assessment. The report provides preliminary estimates of carbon sequestration potential for the central United States including the Corn Belt, the Great Lakes, and portions of the Great Plains. This study region comprises 44% of the land area and 60% to 70% of the agricultural cropland of the conterminous United States. The assessment methodology includes the integration of the RAMS economic model, the Century soil carbon model, meteorologic and soils data bases, and GIS display and analysis capabilities in order to assess the impacts on soil carbon of current agricultural trends and conditions, alternative tillage practices, use of cover crops, and Conservation Reserve Program policy.

  1. Energy efficiency of the cotton agroecosystem on familiar agriculture explorations; Eficiencia energetica do agroecossistema algodao em exploracoes agricolas familiares

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Maria Gloria Cabrera [UNESP, Botucatu, SP (Brazil). Faculdade de Ciencias Agronomicas. Programa de Pos-graduacao em Agronomia. Energia na Agricultura]. E-mail: gloriac@fca.unesp.br; Bueno, Osmar de Carvalho [UNESP, Botucatu, SP (Brazil). Faculdade de Ciencias Agronomicas. Dept. de Gestao e Tecnologia Agroindustrial]. E-mail: Osmar@fca.unesp.br

    2006-07-01

    The aim of this study was to assess the energy efficiency indexes per unit of cotton agroecosystem area. As the focal point of this research, family exploitation is analyzed, with the use of the categorization done by the National Program for Strengthening Family Agriculture (Programa Nacional de Fortalecimento da Agricultura Familiar - PRONAF). Use was made of primary and secondary data from three family exploitations in the municipality of Leme/SP, Brazil. To construct the energy expenditure structure of the cotton agro-ecosystem, the mean values obtained were considered, since these agriculturalists present the same technical itinerary and are within the typification proposed in this study. The energy efficiency was obtained through the making of structure by type, source, form and gross energy. (author)

  2. Impacts of biogas projects on agro-ecosystem in rural areas-A case study of Gongcheng

    Institute of Scientific and Technical Information of China (English)

    Jin YANG; Weichao CHEN; Bin CHEN

    2011-01-01

    The rapid growth of agro-ecosystem has been the focus of "New Rural Construction" in China due to intensive energy consumption and environmental pollution in rural areas.As a kind of renewable energy,biogas is helpful for new energy development and plays an important role in the sustainable development of agroecosystem in China.To evaluate the effects of biogas on agro-ecosystem from a systematic angle,we discussed the status quo of household biogas and identified its main factors that may have impacts on agro-ecosystem.An indicator framework covering environmental,social and economic aspects was established to quantify the impacts exerted by biogas project on agro-ecosystem.A case study of Gongcheng was then conducted to evaluate the combined impact of biogas project using the proposed indicator framework.Results showed that there was a notable positive effect brought by the application of biogas,and the integrated benefit has been significantly improved by 60.36%,implying that biogas as a substitute energy source can promote the sustainable level of rural areas.

  3. Characterization of white grubs (Melolonthidae: Coleoptera at salak pondoh agroecosystem in Mount Merapi based on isozymic banding patterns

    Directory of Open Access Journals (Sweden)

    SRI WARDANI

    2009-03-01

    Full Text Available Wardani S, Sugiyarto. 2009. Characterization of white grubs (Melolonthidae: Coleoptera at salak pondoh agroecosystem in Mount Merapi based on isozymic banding patterns. Nusantara Bioscience 1: 38-42. The aim of this research is to know the characteristics of white grubs (Melolonthidae: Coleoptera based on isozyme banding patterns. This research was conducted at Sleman, Yogyakarta and Magelang-Central Java for the morphological purposes. The sample was taken from 5 places with different height in wich 5 samples were taken from each location. The method used in this research was polyacrylamide gel electrophoresis (PAGE using the vertical type. The enzyme system used in this research were peroxidase and esterase to detect the isozyme banding patterns. The results showed that there was a variation in isozyme banding patterns of white grubs (Melolonthidae: Coleoptera at salak pondoh agroecosystem in Mount Merapi’s slope (peroxidase in station II and IV while esterase in station III and V. It’s mean that genetic variation on white grubs population at salak pondoh agroecosystem in Mount Merapi’s slope was found. The environmental condition also contributed to the influence of the appear of isozyme banding pattern’s variation because each location had a different condition.

  4. The unmanaged reproductive ecology of domesticated plants in traditional agroecosystems: An example involving cassavaand a call for data

    Science.gov (United States)

    Elias, Marianne; McKey, Doyle

    2000-05-01

    Although cassava is a strictly vegetatively propagated crop, in many traditional Amazonian agroecosystems, Amerindian farmers recognise volunteer seedlings of cassava and allow them to grow. If their properties are deemed desirable, plants originating from seedlings are included in the harvest of tuberous roots, and their stems are used to prepare cuttings for propagation. Incorporation of these products of spontaneous sexual reproduction appears to be important in origin and maintenance of genetic diversity in this clonally propagated plant. Our observations conducted in an Amerindian village in Guyana suggest that volunteer seedlings arise from a bank of viable seeds stored in soil, and that dispersal and burial of seeds by ants may be important in its constitution. Future investigations of the dynamics of genetic diversity in this crop in traditional agroecosystems must consider the role of the 'wild' sexual reproduction that occurs in parallel with vegetative propagation. We suggest that unmanaged processes of sexual reproduction play important but neglected roles in the evolutionary ecology of many domesticated plants in traditional agroecosystems.

  5. The Nitrogen Balance of Three Long-term Agroecosystems on a Boreal Soil in Western Canada

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Shirley M.; Izaurralde, Roberto C.; Janzen, H. H.; Robertson, J. A.; Mcgill, William B.

    2008-09-01

    Nitrogen (N) budgets can be used to quantify the flows of N in agroecosystems and to account for differences in losses and retention of N. The objective of our study was to develop 24-year N budgets for three diverse cropping systems on a boreal soil at Breton, Alberta, Canada: AER an agroecological 8-year rotation, with N inputs from legumes [fababean (Vicia faba L.), red clover (Trifolium pratense L.), alfalfa (Medicago sativa L.)] and manure; CF - a continuous perennial grass legume forage system, with N inputs from fertilizer (18 kg N ha-1 yr-1) and white clover (Trifolium repens L.); and CG - a continuous annual grain system, with N fertilizer (90 kg N ha-1 yr-1). We were able to compile detailed N budgets, demonstrate accumulation of soil N, and attribute differences in N flow and permanence to treatment effects. For AER and CG, net inputs almost exactlymatched gains in soil N. The AER system had the highest N flow and the largest net N accumulation. Soil total N mass to 30 cm depth increased in all systems during 1980 2005, but increases were smaller in CG (0.59 Mg N ha-1) than in AER (1.90 Mg N ha-1) and CF (1.63 Mg N ha-1), showing the effect of legumes, perennial species, and manure in the latter systems. The proportion of total N inputs retained as soil N with organic N inputs in AER (44%) was about twice that with synthetic N fertilizer in CG (23%). The CF system had the lowest productivity and the least N loss to the environment (4 kg N ha-1 yr-1, compared to 28 for AER and 24 for CG). The proportion of N inputs lost to the environment was 16% for AER and 24% for CG. In CF, gains of soil N exceeded apparent net N inputs, perhaps because we under-estimated N inputs from clover. Estimate of legume N input was one of the larger sources of uncertainty. The study affirmed the value of N budgets in evaluating agroecosystem performance, and identified AER and CF as productive and sustainable systems due to their minimal reliance on external N inputs and small

  6. Methods and tools for developing virtual territories for scenario analysis of agro-ecosystems

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    Carlo Giupponi

    2016-08-01

    Full Text Available Land evaluation has a leading role in the sustainable management of natural resources. By integrating information from different disciplinary fields and at different spatial scales, concerning soils, climate, vegetation, geomorphology, economic and social drivers, it assesses alternative land uses with consideration of socio-economic and environmental objectives. Over time, the increasing complexity of such an analysis has shown the limits of traditional approaches proposed by Food and Agricultural Organisation and other international institutions in the second half of the 20th century, to deal with relatively new phenomena, such as those related to global change. Among the recent methodological proposals, agro-ecological zoning (AEZ has gained increasing attention of scholars. Global change affects all the variables to be considered for land evaluation and in particular those affecting land productivity and economic consequences, but only rarely they have been jointly considered. Moreover, the possibility of simulating agro-ecosystems over long-time periods in many parts of the world is limited by the great efforts required for data acquisition and the many sources of errors. Our study aims to demonstrate the opportunity to explore the use of virtual territories as analogues of controlled field experiments, in order to carry out scenario analysis of agro-ecosystems, which may exist or not at the moment. Virtual territories exhibit morphological, ecological and land cover features statistically similar to selected existing territories. Provided this basic prerequisite is met, a virtual territory is built as a coherent set of geographic information system layers and databases on which the effects of global change phenomena (e.g., climate and land use changes can be simulated under different scenarios. The advantages are: the possibility of having full control of the experimental conditions; the possibility of setting up factorial experiments with

  7. Characteristics of pristine volcanic materials: Beneficial and harmful effects and their management for restoration of agroecosystem.

    Science.gov (United States)

    Anda, Markus; Suparto; Sukarman

    2016-02-01

    Eruption of Sinabung volcano in Indonesia began again in 2010 after resting for 1200 years. The volcano is daily emitting ash and pyroclastic materials since September 2013 to the present, damaging agroecosystems and costing for management restoration. The objective of the study was to assess properties and impacts of pristine volcanic material depositions on soil properties and to provide management options for restoring the affected agroecosytem. Land satellite imagery was used for field studies to observe the distribution, thickness and properties of ashfall deposition. The pristine ashfall deposits and the underlying soils were sampled for mineralogical, soluble salt, chemical, physical and toxic compound analyses. Results showed that uneven distribution of rainfall at the time of violent eruption caused the areas receiving mud ashfall developed surface encrustation, which was not occur in areas receiving dry ashfall. Ashfall damaged the agroecosytem by burning vegetation, forming surface crusts, and creating soil acidity and toxicity. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses of encrustated layer indicated the presence of gypsum and jarosite minerals. Gypsum likely acted as a cementing agent in the formation of the encrustation layer with extremely low pH (2.9) and extremely high concentrations of Al, Ca and S. Encrustation is responsible for limited water infiltration and root penetration, while the extremely high concentration of Al is responsible for crop toxicity. Mud ashfall and dry ashfall deposits also greatly changed the underlying soil properties by decreasing soil pH and cation exchange capacity and by increasing exchangeable Ca, Al, and S availability. Despite damaging vegetation in the short-term, the volcanic ashfall enriched the soil in the longer term by adding nutrients like Ca, Mg, K, Na, P, Si and S. Suggested management practices to help restore the agroecosystem after volcanic eruptions include: (i) the

  8. Spatio-temporal variation in malaria transmission intensity in five agro-ecosystems in Mvomero district, Tanzania

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    Leonard E. G. Mboera

    2010-05-01

    Full Text Available In Africa, malaria is predominantly a rural disease where agriculture forms the backbone of the economy. Various agro-ecosystems and crop production systems have an impact on mosquito productivity, and hence malaria transmission intensity. This study was carried out to determine spatial and temporal variations in anopheline mosquito population and malaria transmission intensity in five villages, representing different agro-ecosystems in Mvomero district, Tanzania, so as to provide baseline information for malaria interventions. The agro-ecosystems consisted of irrigated sugarcane, flooding rice irrigation, non-flooding rice irrigation, wet savannah and dry savannah. In each setting, adult mosquitoes were sampled monthly using Centers for Disease Control and Prevention (CDC light traps from August 2004 to July 2005. A total of 35,702 female mosquitoes were collected. Anopheles gambiae sensu lato was the most abundant (58.9% mosquito species. An. funestus accounted for 12.0% of the mosquitoes collected. There was a substantial village to village variation and seasonality in the density of Anopheles mosquito population, with peaks in May towards the end of the warm and rainy season. Significantly larger numbers of anophelines were collected from traditional flooding rice irrigation ecosystem (70.7% than in non-flooding rice irrigation (8.6%, sugarcane (7.0%, wet savannah (7.3% and dry savannah (6.4%. The overall sporozoite rates for An. gambiae and An. funestus were 3.4% and 2.3%, respectively. The combined overall sporozoite rate (An. gambiae+An. funestus was 3.2%. The mean annual entomological inoculation rate (EIR for An. gambiae s.l. was 728 infective bites per person per year and this was significantly higher in traditional flooding rice irrigation (1351 than in other agro-ecosystems. The highest EIRs for An. gambiae s.l. and An. funestus were observed during May 2005 (long rainy season and December 2004 (short rainy season, respectively. The

  9. Seasonal infestations of two stem borers (Lepidoptera: Crambidae) in noncrop grasses of Gulf Coast rice agroecosystems.

    Science.gov (United States)

    Beuzelin, J M; Mészáros, A; Reagan, T E; Wilson, L T; Way, M O; Blouin, D C; Showler, A T

    2011-10-01

    Infestations of two stem borers, Eoreuma loftini (Dyar) and Diatraea saccharalis (F.) (Lepidoptera: Crambidae), were compared in noncrop grasses adjacent to rice (Oryza sativa L.) fields. Three farms in the Texas rice Gulf Coast production area were surveyed every 6-8 wk between 2007 and 2009 using quadrat sampling along transects. Although D. saccharalis densities were relatively low, E. loftini average densities ranged from 0.3 to 5.7 immatures per m(2) throughout the 2-yr period. Early annual grasses including ryegrass, Lolium spp., and brome, Bromus spp., were infested during the spring, whereas the perennial johnsongrass, Sorghum halepense (L.) Pers., and Vasey's grass, Paspalum urvillei Steud., were infested throughout the year. Johnsongrass was the most prevalent host (41-78% relative abundance), but Vasey's grass (13-40% relative abundance) harbored as much as 62% of the recovered E. loftini immatures (during the winter). Young rice in newly planted fields did not host stem borers before June. April sampling in fallow rice fields showed that any available live grass material, volunteer rice or weed, can serve as a host during the spring. Our study suggests that noncrop grasses are year-round sources of E. loftini in Texas rice agroecosystems and may increase pest populations.

  10. The Role of the Bacterial Community of an Agroecosystem in Simazine Degradation

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    Anna Barra Caracciolo

    Full Text Available The use of pesticides and fertilizers in agricultural practice is the main source of soil and groundwater contamination. S-Triazines are among the most used herbicides in the world for selective weed control in several types of crops. The homeostatic capability of an agroecosystem to remove a triazinic herbicide, simazine, was assessed in microcosms treated with the herbicide in presence/absence of urea fertilizer. The latter, as well as a fertilizer, is also one of the last by-products before simazine mineralization. The biodegradation, in terms of disappearance of 50% of the initial concentration (DT50, was compared to the degradation and metabolite formation occurring in sterilized soil. Moreover, the bacterial community response was assessed in terms of abundance and community structure by the epifluorescence direct count method and fluorescence in situ hybridization. The results show that the microbial community has a primary role in simazine degradation and that this process is due to the presence of a microbial pool working in succession and of which the metabolism may be modulated by exogenous sources of nitrogen, like urea. The latter influences the degradative pathway with a greater formation and accumulation of the desethyl-simazine metabolite, which is a hazardous contaminant of soil and groundwater ecosystems, as well as its parent compound.

  11. The Role of the Bacterial Community of an Agroecosystem in Simazine Degradation

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    Roberto Ciccoli

    2011-02-01

    Full Text Available The use of pesticides and fertilizers in agricultural practice is the main source of soil and groundwater contamination. S-Triazines are among the most used herbicides in the world for selective weed control in several types of crops. The homeostatic capability of an agroecosystem to remove a triazinic herbicide, simazine, was assessed in microcosms treated with the herbicide in presence/absence of urea fertilizer. The latter, as well as a fertilizer, is also one of the last by-products before simazine mineralization. The biodegradation, in terms of disappearance of 50% of the initial concentration (DT50, was compared to the degradation and metabolite formation occurring in sterilized soil. Moreover, the bacterial community response was assessed in terms of abundance and community structure by the epifluorescence direct count method and fluorescence in situ hybridization. The results show that the microbial community has a primary role in simazine degradation and that this process is due to the presence of a microbial pool working in succession and of which the metabolism may be modulated by exogenous sources of nitrogen, like urea. The latter influences the degradative pathway with a greater formation and accumulation of the desethyl-simazine metabolite, which is a hazardous contaminant of soil and groundwater ecosystems, as well as its parent compound.

  12. Conservation of Agroecosystem through Utilization of Parasitoid Diversity: Lesson for Promoting Sustainable Agriculture and Ecosystem Health

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    DAMAYANTI BUCHORI

    2008-12-01

    Full Text Available For many years, agricultural intensification and exploitation has resulted in biodiversity loss and threaten ecosystem functioning. Developing strategies to bridge human needs and ecosystem health for harmonization of ecosystem is a major concern for ecologist and agriculturist. The lack of information on species diversity of natural enemies and how to utilize them with integration of habitat management that can renovate ecological process was the main obstacle. Parasitoids, a group of natural enemies, play a very important role in regulating insect pest population. During the last ten years, we have been working on exploration of parasitoid species richness, how to use it to restore ecosystem functions, and identifying key factors influencing host-parasitoid interaction. Here, we propose a model of habitat management that is capable of maintaining agricultural biodiversity and ecosystem functions. We present data on parasitoid species richness and distribution in Java and Sumatera, their population structure and its impact toward biological control, relationship between habitat complexes and parasitoid community, spatial and temporal dynamic of parasitoid diversity, and food web in agricultural landscape. Implications of our findings toward conservation of agroecosystem are discussed.

  13. [Quantitative input of atmospheric nitrogen to an agro-ecosystem in a typical red soil region].

    Science.gov (United States)

    Cui, Jian; Zhou, Jing; Yang, Hao; Liang, Jia-ni; Liu, Xiao-li

    2009-08-15

    The atmospheric nitrogen (N) deposition flux and dry deposition N velocities (Vd) were estimated using big leaf resistance analogy model by observations of onflow and factors of farmland microclimate, analysis of nitrides from the atmosphere and rain in an agro-ecosystem, a typical red soil region on Experiment Station of Red Earth Ecology, Chinese Academy (Yingtan, Jiangxi) of Sciences in 2005. The results showed that the dry deposition N was 82.63 kg x hm(-2), accounting for 67.94% of the total N, which was 132.6 kg x hm(-2) in the whole year (2005). In N dry deposition progress, NH3-N and NO3- -N were the main settlement for gas and particle, respectively. NH3-N was made up 43.02% to 89.89% (mean value, 71.05%) of the gaseous N deposition while NO3- -N was accounted for 33.67% to 94.54% (mean value, 61.01%) of the particle N deposition. The N wet deposition fluxes were 0.50-8.45 kg x hm(-2) per month and reached the higher value in July and November.

  14. Upscaling Arbuscular Mycorrhizal Symbiosis and Related Agroecosystems Services in Smallholder Farming Systems

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    Marjorie Bonareri Oruru

    2016-01-01

    Full Text Available Smallholder farming systems form unique ecosystems that can protect beneficial soil biota and form an important source of useful genetic resources. They are characterized by high level of agricultural diversity mainly focused on meeting farmers’ needs. Unfortunately, these systems often experience poor crop production mainly associated with poor planning and resource scarcity. Soil fertility is among the primary challenges faced by smallholder farmers, which necessitate the need to come up with affordable and innovative ways of replenishing soils. One such way is the use of microbial symbionts such as arbuscular mycorrhizal fungi (AMF, a beneficial group of soil microbiota that form symbiotic associations with majority of cultivated crops and play a vital role in biological soil fertility, plant nutrition, and protection. AMF can be incorporated in smallholder farming systems to help better exploit chemical fertilizers inputs which are often unaffordable to many smallholder farmers. The present review highlights smallholder farming practices that could be innovatively redesigned to increase AMF symbiosis and related agroecosystem services. Indeed, the future of global food security depends on the success of smallholder farming systems, whose crop productivity depends on the services provided by well-functioning ecosystems, including soil fertility.

  15. Diversity, abundance and conservation of birds in an agroecosystem in the Ica desert, Peru

    Directory of Open Access Journals (Sweden)

    Letty Salinas

    2013-05-01

    Full Text Available Present work investigates the impact of the agricultural activity in the Peruvian coast on the biodiversity of birds. The study includes the monitoring of birds in asparagus and grapes farms of Ica valley, from January-2004 to January-2006. We evaluated eight types of habitats distributed in a total of 1288 has. Throughout the period of study we registered 93 species of birds. The abundance, richness and diversity were greater in the summers. The greater abundance happened in the habitats of land of asparagus, river brushwood and live fences. The greater richness and diversity happened in January-2006 in alfalfa cultures with huarangos and live fences. The most abundant species were the residents, as Zenaida meloda (6,6 ind./it has, Pygochelidon cyanoleuca (5,9 and the migratory Hirundo rustica (5,9. We registered 12 migratory species. From the conservationist point of view, the number of species catalogued in some degree of threat, at national and international level, is very high. We can emphasize the vulnerable Xenospingus concolor, the Peruvian endemic Colaptes atricollis and the species of desert Geositta peruviana, Sporophila simplex and Burhinus superciliaris. This study demonstrates the importance of agroecosystems in the conservation of the Peruvian Coastal Desert biodiversity, in particular if the enterprise carries out a policy of respect to environment.

  16. Managing Soil Biota-Mediated Decomposition and Nutrient Mineralization in Sustainable Agroecosystems

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    Joann K. Whalen

    2014-01-01

    Full Text Available Transformation of organic residues into plant-available nutrients occurs through decomposition and mineralization and is mediated by saprophytic microorganisms and fauna. Of particular interest is the recycling of the essential plant elements—N, P, and S—contained in organic residues. If organic residues can supply sufficient nutrients during crop growth, a reduction in fertilizer use is possible. The challenge is synchronizing nutrient release from organic residues with crop nutrient demands throughout the growing season. This paper presents a conceptual model describing the pattern of nutrient release from organic residues in relation to crop nutrient uptake. Next, it explores experimental approaches to measure the physical, chemical, and biological barriers to decomposition and nutrient mineralization. Methods are proposed to determine the rates of decomposition and nutrient release from organic residues. Practically, this information can be used by agricultural producers to determine if plant-available nutrient supply is sufficient to meet crop demands at key growth stages or whether additional fertilizer is needed. Finally, agronomic practices that control the rate of soil biota-mediated decomposition and mineralization, as well as those that facilitate uptake of plant-available nutrients, are identified. Increasing reliance on soil biological activity could benefit crop nutrition and health in sustainable agroecosystems.

  17. PROFILE: Tourism Contribution to Agro-Ecosystems Conservation: The Case of Lesbos Island, Greece.

    Science.gov (United States)

    Loumou; Giourga; Dimitrakopoulos; Koukoulas

    2000-10-01

    / The modernization of agriculture and the development of other economic sectors have prompted the abandonment of cultivated areas, which are marginally productive. Specifically, olive groves in Greece are transformed into pastures due to their location in inaccessible mountainous regions where breeding and raising of sheep and goats are the main economic activities. Overgrazing degrades the environment, exhausts natural resources, and prevents natural regeneration. The Greek islands have limited possibilities of development, except for their coastal areas where the growth of tourism is possible.The objective of this study was to investigate the impact of tourism activities on olive tree cultivation and the human population of the island of Lesbos. The presence or absence of tourism is related with the maintenance or abandonment of olive tree cultivation and population changes for each community. A spatial segregation of the island is evident, related to tourist development, olive tree cultivation, and population change. The results of the study demonstrate that in communities where tourism plays an important role olive tree cultivation is preserved and the population is stable. The preservation of the agro-ecosystem is assured while the olive groves remain productive. Simultaneously, the landscape, which provides specific attractions for tourism, is not altered.

  18. Differences in Soil Microbial Biomass and Activity for Six Agroecosystems with a Management Disturbance Gradient

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei-Jian; FENG Jin-Xia; J. WU; K. PARKER

    2004-01-01

    Different management practices in six agroecosystems located near Goldsboro, NC, USA were conducted including a successional field (SU), a plantation woodlot (WO), an integrated cropping system with animals (IN), an organic farming system (OR), and two cash-grain cropping systems employing either tillage (CT) or no-tillage (NT) to examine if and how microbial biomass and activity differ in response to alterations in disturbance intensity from six land management strategies. Results showed that soil microbial biomass and activity differed, with microbial activity in intermediately disturbed ecosystems (NT, OR, IN) being significantly higher (P < 0.01) than systems with either high or low disturbance intensities. There was also a significant and a highly significant ecosystem effect from the treatments on microbial biomass C (MBC) (P < 0.05) and on microbial activity (respiration) (P < 0.01), respectively. Multiple comparisons of mean respiration rates distinctly separated the six ecosystem types into three groups: CT < NT, SU and WO < OR and IN.Thus, for detecting microbial response to disturbance changes these results indicated that the active component of the soil microbial community was a better indicator than total biomass.

  19. [Emergy of agro-ecosystem in Hunan Province: evolution and trend].

    Science.gov (United States)

    Zhu, Yu-Lin; Li, Ming-Jie

    2012-02-01

    By using emergy analysis method, a trend analysis was made on the total emergy, its input-output structure, and emergy indices of the agro-ecosystem in Hunan Province of South-central China from 1999 to 2008. In the study period, the available total emergy input of the ecosystem was basically maintained at a stable level, but the input structure changed with the input of non-renewable industrial auxiliary emergy increased from 4.00E+22 sej in 1999 to 5.53E+22 sej in 2008, while that of renewable organic emergy decreased from 1.32E+23 sej to 1.20E+23 sej. Both the total emergy output and the output efficiency of the ecosystem had a great increase, with the total output reached 1.69E+23 sej in 2008, which was 23.8% higher than that in 1999, and the net output ratio increased from 0.79 to 0.96. Owing to the ever-increasing trend of the environmental loading ratio which was from 1.12 to 1.79, the sustainable development index of the ecosystem presented a decreasing trend, from 0.71 to 0.54, indicating that the agriculture in Hunan Province was overall belonged to the type of ecosystem driven by high consumption, and had relatively apparent extensive development characteristics.

  20. Diversity and Dynamics of Soil Free-Living Nematode Populations in a Mediterranean Agroecosystem

    Institute of Scientific and Technical Information of China (English)

    LIANG Wen-Ju; I.LAVIAN; S.PEN-MOURATOV; Y.STEINBERGER

    2005-01-01

    To determine the effect of agricultural management on the dynamics and functional diversity of soil nematode communities in a carrot field at Kibbutz Ramat Hakovesh, Israel, soil samples from 0-10 cm and 10-20 cm depths were collected during the growing season of carrot. Indices were used to compare and assess the response of soil free-living nematode communities to agricultural management. Eighteen nematode families and 20 genera were observed during the growing period, with Cephalobus, Rhabditidae, Aphelenchus, Tylenchus, and Dorylaimus being the dominant genera/families.During the planting, mid-season and post-harvest periods the total number of nematodes at both depths was significantly lower (P < 0.01) in the carrot treatment than in the control plots, while during the harvest period at both depths total nematodes and bacterivores were significantly higher in the treatment plots (P < 0.01). The values of the maturity index (MI) at both depths were found to be significantly lower in the treatment plots than in the control plots during the pre-planting period (P < 0.05). Overall, WI, MI and PPI were found to be more sensitive indicators than other ecological indices for assessing the response of nematode communities to agricultural management in a Mediterranean agroecosystem.

  1. Species composition and seasonal abundance of sandflies (Diptera: Psychodidae: Phlebotominae in coffee agroecosystems

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    Jeanneth Perez

    2014-02-01

    Full Text Available The composition and seasonal occurrence of sandflies were investigated in coffee agroecosystems in the Soconusco region of Chiapas, Mexico. Insect sampling was performed on three plantations located at different altitudes: Finca Guadalupe Zajú [1,000 m above sea level (a.s.l.], Finca Argovia (613 m a.s.l. and Teotihuacán del Valle (429 m a.s.l.. Sandflies were sampled monthly from August 2007-July 2008 using three sampling methods: Shannon traps, CDC miniature light traps and Disney traps. Sampling was conducted for 3 h during three consecutive nights, beginning at sunset. A total of 4,387 sandflies were collected during the course of the study: 2,718 individuals in Finca Guadalupe Zajú, 605 in Finca Argovia and 1,064 in Teotihuacán del Valle. The Shannon traps captured 94.3% of the total sandflies, while the CDC light traps and Disney traps captured 4.9% and 0.8%, respectively. More females than males were collected at all sites. While the number of sandflies captured was positively correlated with temperature and relative humidity, a negative correlation was observed between sandfly numbers and rainfall. Five species of sandflies were captured: Lutzomyia cruciata , Lutzomyia texana , Lutzomyia ovallesi , Lutzomyia cratifer / undulata and Brumptomyia sp. Lu. cruciata , constituting 98.8% of the total, was the most abundant species. None of the captured sandflies was infected with Leishmania spp.

  2. Species composition and seasonal abundance of sandflies (Diptera: Psychodidae: Phlebotominae) in coffee agroecosystems.

    Science.gov (United States)

    Pérez, Jeanneth; Virgen, Armando; Rojas, Julio Cesar; Rebollar-Téllez, Eduardo Alfonso; Alfredo, Castillo; Infante, Francisco; Mikery, Oscar; Marina, Carlos Felix; Ibáñez-Bernal, Sergio

    2014-02-01

    The composition and seasonal occurrence of sandflies were investigated in coffee agroecosystems in the Soconusco region of Chiapas, Mexico. Insect sampling was performed on three plantations located at different altitudes: Finca Guadalupe Zajú [1,000 m above sea level (a.s.l.)], Finca Argovia (613 m a.s.l.) and Teotihuacán del Valle (429 m a.s.l.). Sandflies were sampled monthly from August 2007-July 2008 using three sampling methods: Shannon traps, CDC miniature light traps and Disney traps. Sampling was conducted for 3 h during three consecutive nights, beginning at sunset. A total of 4,387 sandflies were collected during the course of the study: 2,718 individuals in Finca Guadalupe Zajú, 605 in Finca Argovia and 1,064 in Teotihuacán del Valle. The Shannon traps captured 94.3% of the total sandflies, while the CDC light traps and Disney traps captured 4.9% and 0.8%, respectively. More females than males were collected at all sites. While the number of sandflies captured was positively correlated with temperature and relative humidity, a negative correlation was observed between sandfly numbers and rainfall. Five species of sandflies were captured: Lutzomyia cruciata , Lutzomyia texana , Lutzomyia ovallesi , Lutzomyia cratifer / undulata and Brumptomyia sp. Lu. cruciata , constituting 98.8% of the total, was the most abundant species. None of the captured sandflies was infected with Leishmania spp.

  3. More of the Same: High Functional Redundancy in Stream Fish Assemblages from Tropical Agroecosystems

    Science.gov (United States)

    Casatti, Lilian; Teresa, Fabrício Barreto; Zeni, Jaquelini de Oliveira; Ribeiro, Mariela Domiciano; Brejão, Gabriel Lourenço; Ceneviva-Bastos, Mônica

    2015-06-01

    In this study, we investigated the influence of environmental variables (predictor variables) on the species richness, species diversity, functional diversity, and functional redundancy (response variables) of stream fish assemblages in an agroecosystem that harbor a gradient of degradation. We hypothesized that, despite presenting high richness or diversity in some occasions, fish communities will be more functionally redundant with stream degradation. Species richness, species diversity, and functional redundancy were predicted by the percentage of grass on the banks, which is a characteristic that indicates degraded conditions, whereas the percentage of coarse substrate in the stream bottom was an important predictor of all response variables and indicates more preserved conditions. Despite being more numerous and diverse, the groups of species living in streams with an abundance of grass on the banks perform similar functions in the ecosystem. We found that riparian and watershed land use had low predictive power in comparison to the instream habitat. If there is any interest in promoting ecosystem functions and fish diversity, conservation strategies should seek to restore forests in watersheds and riparian buffers, protect instream habitats from siltation, provide wood debris, and mitigate the proliferation of grass on stream banks. Such actions will work better if they are planned together with good farming practices because these basins will continue to be used for agriculture and livestock in the future.

  4. Copro-necrophagous beetle (Coleoptera: Scarabaeidae) diversity in an agroecosystem in Yucatan, Mexico.

    Science.gov (United States)

    Reyes Novelo, Enrique; Delfín-González, Hugo; Angel Morón, Miguel

    2007-03-01

    Scarabaeinae are sensitive to structural habitat changes caused by disturbance. We compared copronecrophagous beetle (Scarabaeinae) community structure in three differently managed zones within an agroeco-system of the northern Yucatan Peninsula, Mexico. We placed dung and carrion traps once a month from June 2004 through May 2005. The beetle community included 17 species from the genera Canthon, Canthidium, Deltochilum, Pseudocanthon, Malagoniella, Onthophagus, Phanaeus, Copris, Uroxys, Sisyphus and Ateuchus. The secondary vegetation had a higher beetle diversity than the other two zones. Species richness was highest in the Brosimum alicastrum plantation. The pasture had the lowest species diversity and richness, but exhibited the highest abundance of Scarabaeinae in the dry season. The two zones with extensive tree cover were the most diverse. Roller beetles were dominant over burrower species and small-sized species outnumbered large species. Our data show two important issues: beetle species in the pasture extended their activity to the beginning of the dry season, while abundances dropped in the other, unirrigated zones; and the possibility that the Scarabaeinae living in neotropical forests are opportunistic saprophages and have specialized habits for resources other than dung. The B. alicastrum plantation is beneficial to the entire ranch production system because it functions as a dispersion and development area for stenotopic species limited to tree cover.

  5. Monitoring of the CO2 emission and the contents of microbial biomass in agroecosystems on gray forest soils of the Cisbaikal region under conditions of fluoride pollution

    Science.gov (United States)

    Pomazkina, L. V.

    2015-08-01

    The influence of the technogenic pollution of gray forest soils in the forest-steppe zone of the Cisbaikal region with fluorides emitted by aluminum smelters on the functioning and state of local agroecosystems was studied within the framework of a long-term agroecological monitoring program. Hydrothermic conditions of the growing season during the monitoring period (1997-2012) were compared with the climatic norm (1961-1990). It was found that the adverse effect of the technogenic pollution on the agroecosystem becomes more pronounced during the years with abnormal weather conditions. An increase in the CO2 emission into the atmosphere as a response of the microbial complex to the rise in the air temperatures was characterized by the linear dependence irrespectively of the degree of soil contamination. The methods of systems analysis were applied to generalize the results. The considered agroecosystem was studied as the system of particular components (soil-microorganisms-plants-atmosphere) integrated by the carbon fluxes. The regimes of the agroecosystem functioning and the ecological loads on it were estimated on the basis of data on the fluxes of net mineralized and (re)immobilized carbon. The environmental factors affecting the state and functioning of the agroecosystem were identified.

  6. Carbon balance at represenative agroecosystems of Central European Russia with different crops assessed by eddy covariance method

    Science.gov (United States)

    Yaroslavtsev, Alexis; Meshalkina, Joulia; Mazirov, Ilya

    2016-04-01

    Despite the fact that in Russia cropland's soils carbon loses 9 time higher than forest's soils ones (Stolbovoi, 2002), agroecosystems were not given sufficient attention and most of the papers are devoted to forestry and natural ecosystems. Carbon balance was calculated at the Precision Farming Experimental Fields of the Russian Timiryazev State Agricultural University, Moscow, Russia, for two agroecosystems with different crops from the same crop rotation studied for 2 years. The experimental site has a temperate and continental climate and situated in south taiga zone with Arable Sod-Podzoluvisols (Albeluvisols Umbric). Vertical fluxes of carbon dioxide were measured with eddy covariance technique, statistical method to measure and calculate turbulent fluxes within atmospheric boundary layers (Burba, 2013). Crop rotation included potato, winter wheat, barley and vetch and oat mix. Two fields of the same crop rotation were studied in 2013-2014. One of the fields (A) was used in 2013 for barley planting (Hordeum vulgare L.). The field B was in 2013 used for planting together vetch (Vicia sativa L.) and oats (Avena sativa L.). Inversely oats and vetch grass mixt was sown in 2014 on field A. Winter wheat was sown on field A in the very beginning of September. On the second field (B) in 2014 winter wheat occurred from under the snow in the phase of tillering, after harvesting it in mid of July, white mustard (Sinapis alba) was sown for green manure. Carbon uptake (NEE negative values) was registered only for the field with winter wheat and white mustard; perhaps because the two crops were cultivated on the field within one growing season. Three other cases showed CO2 emission. Great difference in 82 g C m-2 per year in NEE between two fields with vetch and oat mix was related to higher difference in grass yields. NEE for barley field was positive during the whole year; considering only the growing season, NEE for barley was 100 g C m-2 lower and was negative. Closed

  7. Long-term agroecosystem research in the central Mississippi river basin: introduction, establishment, and overview.

    Science.gov (United States)

    Sadler, E John; Lerch, Robert N; Kitchen, Newell R; Anderson, Stephen H; Baffaut, Claire; Sudduth, Kenneth A; Prato, Anthony A; Kremer, Robert J; Vories, Earl D; Myers, D Brent; Broz, Robert; Miles, Randall J; Young, Fred J

    2015-01-01

    Many challenges currently facing agriculture require long-term data on landscape-scale hydrologic responses to weather, such as from the Goodwater Creek Experimental Watershed (GCEW), located in northeastern Missouri, USA. This watershed is prone to surface runoff despite shallow slopes, as a result of a significant smectitic clay layer 30 to 50 cm deep that restricts downward flow of water and gives rise to a periodic perched water table. This paper is the first in a series that documents the database developed from GCEW. The objectives of this paper are to (i) establish the context of long-term data and the federal infrastructure that provides it, (ii) describe the GCEW/ Central Mississippi River Basin (CMRB) establishment and the geophysical and anthropogenic context, (iii) summarize in brief the collected research results published using data from within GCEW, (iv) describe the series of papers this work introduces, and (v) identify knowledge gaps and research needs. The rationale for the collection derives from converging trends in data from long-term research, integration of multiple disciplines, and increasing public awareness of increasingly larger problems. The outcome of those trends includes being selected as the CMRB site in the USDA-ARS Long-Term Agro-Ecosystem Research (LTAR) network. Research needs include quantifying watershed scale fluxes of N, P, K, sediment, and energy, accounting for fluxes involving forest, livestock, and anthropogenic sources, scaling from near-term point-scale results to increasingly long and broad scales, and considering whole-system interactions. This special section informs the scientific community about this database and provides support for its future use in research to solve natural resource problems important to US agricultural, environmental, and science policy.

  8. The challenge of accurately documenting bee species richness in agroecosystems: bee diversity in eastern apple orchards.

    Science.gov (United States)

    Russo, Laura; Park, Mia; Gibbs, Jason; Danforth, Bryan

    2015-09-01

    Bees are important pollinators of agricultural crops, and bee diversity has been shown to be closely associated with pollination, a valuable ecosystem service. Higher functional diversity and species richness of bees have been shown to lead to higher crop yield. Bees simultaneously represent a mega-diverse taxon that is extremely challenging to sample thoroughly and an important group to understand because of pollination services. We sampled bees visiting apple blossoms in 28 orchards over 6 years. We used species rarefaction analyses to test for the completeness of sampling and the relationship between species richness and sampling effort, orchard size, and percent agriculture in the surrounding landscape. We performed more than 190 h of sampling, collecting 11,219 specimens representing 104 species. Despite the sampling intensity, we captured orchard size, and sampling effort, but we found no factors explaining the difference between observed and expected species richness. Competition between honeybees and wild bees did not appear to be a factor, as we found no correlation between honeybee and wild bee abundance. Our study shows that the pollinator fauna of agroecosystems can be diverse and challenging to thoroughly sample. We demonstrate that there is high temporal variation in community composition and that sites vary widely in the sampling effort required to fully describe their diversity. In order to maximize pollination services provided by wild bee species, we must first accurately estimate species richness. For researchers interested in providing this estimate, we recommend multiyear studies and rarefaction analyses to quantify the gap between observed and expected species richness.

  9. Landscape constraints on functional diversity of birds and insects in tropical agroecosystems.

    Science.gov (United States)

    Tscharntke, Teja; Sekercioglu, Cagan H; Dietsch, Thomas V; Sodhi, Navjot S; Hoehn, Patrick; Tylianakis, Jason M

    2008-04-01

    In this paper, we analyze databases [corrected] on birds and insects to assess patterns of functional diversity in human-dominated landscapes in the tropics. A perspective from developed landscapes is essential for understanding remnant natural ecosystems, because most species experience their surroundings at spatial scales beyond the plot level, and spillover between natural and managed ecosystems is common. Agricultural bird species have greater habitat and diet breadth than forest species. Based on a global data base, bird assemblages in tropical agroforest ecosystems were composed of disproportionately more frugivorous and nectarivorous, but fewer insectivorous bird species compared with forest. Similarly, insect predators of plant-feeding arthropods were more diverse in Ecuadorian agroforest and forest compared with rice and pasture, while, in Indonesia, bee diversity was also higher in forested habitats. Hence, diversity of insectivorous birds and insect predators as well as bee pollinators declined with agricultural transformation. In contrast, with increasing agricultural intensification, avian pollinators and seed dispersers initially increase then decrease in proportion. It is well established that the proximity of agricultural habitats to forests has a strong influence on the functional diversity of agroecosystems. Community similarity is higher among agricultural systems than in natural habitats and higher in simple than in complex landscapes for both birds and insects, so natural communities, low-intensity agriculture, and heterogeneous landscapes appear to be critical in the preservation of beta diversity. We require a better understanding of the relative role of landscape composition and the spatial configuration of landscape elements in affecting spillover of functionally important species across managed and natural habitats. This is important for data-based management of tropical human-dominated landscapes sustaining the capacity of communities to

  10. Modeling Sustained Delivery of Agroecosystem Services at a Watershed Scale under Climate Change

    Science.gov (United States)

    Jaradat, A. A.; Starr, J.

    2015-12-01

    The intensive land use and agricultural production systems in the Chippewa River Watershed (CRW) in Minnesota, USA, contribute to inherent environmental problems and have major direct impact on soil conservation, and on several competing agro-ecosystem services (AESs); and may have indirect impact on AESs in the Upper Mississippi River Basin (UMRB). Field-scale indicators of AESs are largely absent in the highly diverse soils of the CRW. Therefore, proxy indicators were developed to assess these services under current (A0) and predicted (A2; 100 years) global climate change (GCC) scenarios. Individual indices were developed for biomass, grain yield, NO3- and NH4-N, soil carbon, runoff, and soil erosion for 132 soil series classified into three land capability classes (LCCs). The indices and a weighted index (Iw) were subjected to multivariate analyses procedures, including distance-weighted least squares, and variance components estimation. Three-D maps delineated contiguous areas of increasing or decreasing AESs in response to projected GCC. Largest significant variance portions in Iw were attributed to GCC scenarios; followed by the interaction of crop rotations and LCCs within conventional and organic cropping systems. The AES were predicted with larger certainty under A2 in organically-managed LCC-1 compared to conventional management. Significantly more runoff and soil erosion are predicted in conventionally-managed LCC-2 and LCC-3 under the same GCC scenario, regardless of soil heterogeneity. The modeling framework and the mapped AES indicators are designed to achieve multiple goals and will be used to support farmers in designing specific crop rotations that are suitable for each of the three LCCs and for major and vulnerable soil series in the watershed. Also, the modeling framework will address sustained delivery of multiple AESs, while enhancing soil conservation, water quality, and environmental protection aspects of farming in the CRW and the UMRB.

  11. Metagenomic Evidence of the Prevalence and Distribution Patterns of Antimicrobial Resistance Genes in Dairy Agroecosystems.

    Science.gov (United States)

    Pitta, Dipti W; Dou, Zhengxia; Kumar, Sanjay; Indugu, Nagaraju; Toth, John Daniel; Vecchiarelli, Bonnie; Bhukya, Bhima

    2016-06-01

    Antimicrobial resistance (AR) is a global problem with serious implications for public health. AR genes are frequently detected on animal farms, but little is known about their origin and distribution patterns. We hypothesized that AR genes can transfer from animal feces to the environment through manure, and to this end, we characterized and compared the resistomes (collections of AR genes) of animal feces, manure, and soil samples collected from five dairy farms using a metagenomics approach. Resistomes constituted only up to 1% of the total gene content, but were variable by sector and also farm. Broadly, the identified AR genes were associated with 18 antibiotic resistances classes across all samples; however, the most abundant genes were classified under multidrug transporters (44.75%), followed by resistance to vancomycin (12.48%), tetracycline (10.52%), bacitracin (10.43%), beta-lactam resistance (7.12%), and MLS efflux pump (6.86%) antimicrobials. The AR gene profiles were variable between farms. Farm 09 was categorized as a high risk farm, as a greater proportion of AR genes were common to at least three sectors, suggesting possible horizontal transfer of AR genes. Taxonomic characterization of AR genes revealed that a majority of AR genes were associated with the phylum Proteobacteria. Nonetheless, there were several members of Bacteroidetes, particularly Bacteroides genus and several lineages from Firmicutes that carried similar AR genes in different sectors, suggesting a strong potential for horizontal transfer of AR genes between unrelated bacterial hosts in different sectors of the farms. Further studies are required to affirm the horizontal gene transfer mechanisms between microbiomes of different sectors in animal agroecosystems.

  12. Impact of weed control on arbuscular mycorrhizal fungi in a tropical agroecosystem: a long-term experiment.

    Science.gov (United States)

    Ramos-Zapata, José A; Marrufo-Zapata, Denis; Guadarrama, Patricia; Carrillo-Sánchez, Lilia; Hernández-Cuevas, Laura; Caamal-Maldonado, Arturo

    2012-11-01

    Cover crop species represent an affordable and effective weed control method in agroecosystems; nonetheless, the effect of its use on arbuscular mycorrhizal fungi (AMF) has been scantily studied. The goal of this study was to determine root colonization levels and AMF species richness in the rhizosphere of maize plants and weed species growing under different cover crop and weed control regimes in a long-term experiment. The treatment levels used were (1) cover of Mucuna deeringian (Muc), (2) "mulch" of Leucaena leucocephala (Leu), (3) "mulch" of Lysiloma latisiliquum (Lys), (4) herbicide (Her), (5) manual weeding (CD), (6) no weeding (SD), and (7) no maize and no weeding (B). A total of 18 species of AMF belonging to eight genera (Acaulospora, Ambispora, Claroideoglomus, Funneliformis, Glomus, Rhizophagus, Sclerocystis, and Scutellospora) were identified from trap cultures. Muc and Lys treatments had a positive impact on AMF species richness (11 and seven species, respectively), while Leu and B treatments on the other hand gave the lowest richness values (six species each). AMF colonization levels in roots of maize and weeds differed significantly between treatment levels. Overall, the use of cover crop species had a positive impact on AMF species richness as well as on the percentage of root colonized by AMF. These findings have important implications for the management of traditional agroecosystems and show that the use of cover crop species for weed control can result in a more diverse AMF community which should potentially increase crop production in the long run.

  13. Paisang ( Quercus griffithii): A Keystone Tree Species in Sustainable Agroecosystem Management and Livelihoods in Arunachal Pradesh, India

    Science.gov (United States)

    Singh, Ranjay K.; Singh, Anshuman; Garnett, Stephen T.; Zander, Kerstin K.; Lobsang; Tsering, Darge

    2015-01-01

    In a study of the traditional livelihoods of 12 Monpa and Brokpa villages in Arunachal Pradesh, India using social-ecological and participatory rural appraisal techniques, we found that the forest tree species paisang ( Quercus griffithii, a species of oak) is vital to agroecosystem sustainability. Paisang trees are conserved both by individuals and through community governance, because their leaves play a crucial role in sustaining 11 traditional cropping systems of the Monpa peoples. An Indigenous institution, Chhopa, regulates access to paisang leaves, ensuring that the relationship between paisang and traditional field crop species within Monpa agroecosystems is sustainable. The Monpa farmers also exchange leaves and agricultural products for yak-based foods produced by the transhumant Brokpa, who are primarily yak herders. Yak herds also graze in paisang groves during winter. These practices have enabled the conservation of about 33 landraces, yak breeds, and a number of wild plants. Paisang thus emerged as a culturally important keystone species in the cultures and livelihoods of both Monpa and Brokpa. Ecological and conservation knowledge and ethics about paisang vary with gender, social systems, and altitudes. Labor shortages, however, have already caused some changes to the ways in which paisang leaves are used and yak grazing patterns are also changing in the face of changes in attitude among local landowners. Given new competing interests, incentives schemes are now needed to conserve the ecologically sustainable traditional livelihoods.

  14. Balancing competition for resources with multiple pest regulation in diversified agroecosystems: a process-based approach to reconcile diversification and productivity.

    Science.gov (United States)

    Poeydebat, Charlotte; Carval, Dominique; de Lapeyre de Bellaire, Luc; Tixier, Philippe

    2016-12-01

    Agroecosystem plant diversification can enhance pest biological regulation and is a promising alternative to pesticide application. However, the costs of competition for resources between plants may exceed the benefits gained by pest regulation. To disentangle the interactions between pest regulation and competition, we developed a generic process-based approach that accounts for the effects of an associated plant and leaf and root pests on biomass production. We considered three crop-plant associations that differ in competition profiles, and we simulated biomass production under wide ranges of both pest regulation rates and resources' availability. We analyzed outputs to quantify the pest regulation service level that would be required to attain monoculture yield and other production goals. Results showed that pest regulation requirements were highly dependent on the profile of resource interception of the associated plant and on resources' availability. Pest regulation and the magnitude of competition between plants interacted in determining the balance between nitrogen and radiation uptake by the crop. Our findings suggest that productivity of diversified agroecosystems relative to monoculture should be optimized by assembling plants whose characteristics balance crops' resource acquisition. The theoretical insights from our study draw generic rules for vegetation assemblage to optimize trade-offs between pest regulation and production. Our findings and approach may have implications in understanding, theorizing and implementing agroecosystem diversification. By its generic and adaptable structure, our approach should be useful for studying the effects of diversification in many agroecosystems.

  15. Land use systems analysis as a tool in land use planning, with special reference to North and West African agro-ecosystems.

    NARCIS (Netherlands)

    Duivenbooden, van N.

    1995-01-01

    Results of multidisciplinary projects have contributed to a new approach in land use planning. Part A presents a survey method for characterizing land use, and an interactive multiple-goal linear programming (MGLP) model for quantifying relations in agro-ecosystems. In Part B, nutrient relations in

  16. 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

    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...

  17. Reduction of soluble nitrogen and mobilization of plant nutrients in soils from U.S. northern Great Plains agroecosystems by phenolic compounds

    Science.gov (United States)

    Phenolic plant secondary metabolites actively participate in a broad range of important reactions that affect livestock, plants and soil. In soil, phenolic compounds can affect nutrient dynamics and mobility of metals but their role in northern Great Plains agroecosystems is largely unknown. We eval...

  18. Designing efficient nitrous oxide sampling strategies in agroecosystems using simulation models

    Science.gov (United States)

    Saha, Debasish; Kemanian, Armen R.; Rau, Benjamin M.; Adler, Paul R.; Montes, Felipe

    2017-04-01

    Annual cumulative soil nitrous oxide (N2O) emissions calculated from discrete chamber-based flux measurements have unknown uncertainty. We used outputs from simulations obtained with an agroecosystem model to design sampling strategies that yield accurate cumulative N2O flux estimates with a known uncertainty level. Daily soil N2O fluxes were simulated for Ames, IA (corn-soybean rotation), College Station, TX (corn-vetch rotation), Fort Collins, CO (irrigated corn), and Pullman, WA (winter wheat), representing diverse agro-ecoregions of the United States. Fertilization source, rate, and timing were site-specific. These simulated fluxes surrogated daily measurements in the analysis. We ;sampled; the fluxes using a fixed interval (1-32 days) or a rule-based (decision tree-based) sampling method. Two types of decision trees were built: a high-input tree (HI) that included soil inorganic nitrogen (SIN) as a predictor variable, and a low-input tree (LI) that excluded SIN. Other predictor variables were identified with Random Forest. The decision trees were inverted to be used as rules for sampling a representative number of members from each terminal node. The uncertainty of the annual N2O flux estimation increased along with the fixed interval length. A 4- and 8-day fixed sampling interval was required at College Station and Ames, respectively, to yield ±20% accuracy in the flux estimate; a 12-day interval rendered the same accuracy at Fort Collins and Pullman. Both the HI and the LI rule-based methods provided the same accuracy as that of fixed interval method with up to a 60% reduction in sampling events, particularly at locations with greater temporal flux variability. For instance, at Ames, the HI rule-based and the fixed interval methods required 16 and 91 sampling events, respectively, to achieve the same absolute bias of 0.2 kg N ha-1 yr-1 in estimating cumulative N2O flux. These results suggest that using simulation models along with decision trees can reduce

  19. Including sugar cane in the agro-ecosystem model ORCHIDEE-STICS

    Science.gov (United States)

    Valade, A.; Vuichard, N.; Ciais, P.; Viovy, N.

    2010-12-01

    With 4 million ha currently grown for ethanol in Brazil only, approximately half the global bioethanol production in 2005 (Smeets 2008), and a devoted land area expected to expand globally in the years to come, sugar cane is at the heart of the biofuel debate. Indeed, ethanol made from biomass is currently the most widespread option for alternative transportation fuels. It was originally promoted as a carbon neutral energy resource that could bring energy independence to countries and local opportunities to farmers, until attention was drawn to its environmental and socio-economical drawbacks. It is still not clear to which extent it is a solution or a contributor to climate change mitigation. Dynamic Global Vegetation models can help address these issues and quantify the potential impacts of biofuels on ecosystems at scales ranging from on-site to global. The global agro-ecosystem model ORCHIDEE describes water, carbon and energy exchanges at the soil-atmosphere interface for a limited number of natural and agricultural vegetation types. In order to integrate agricultural management to the simulations and to capture more accurately the specificity of crops' phenology, ORCHIDEE has been coupled with the agronomical model STICS. The resulting crop-oriented vegetation model ORCHIDEE-STICS has been used so far to simulate temperate crops such as wheat, corn and soybean. As a generic ecosystem model, each grid cell can include several vegetation types with their own phenology and management practices, making it suitable to spatial simulations. Here, ORCHIDEE-STICS is altered to include sugar cane as a new agricultural Plant functional Type, implemented and parametrized using the STICS approach. An on-site calibration and validation is then performed based on biomass and flux chamber measurements in several sites in Australia and variables such as LAI, dry weight, heat fluxes and respiration are used to evaluate the ability of the model to simulate the specific

  20. A transdisciplinary perspective on the links between malaria and agroecosystems in Kenya.

    Science.gov (United States)

    Mutero, C M; Kabutha, C; Kimani, V; Kabuage, L; Gitau, G; Ssennyonga, J; Githure, J; Muthami, L; Kaida, A; Musyoka, L; Kiarie, E; Oganda, M

    2004-01-01

    V consisted of end-of-project workshops for the dissemination of research results and participatory decision-making regarding follow-up actions. Owing to the utilization of a transdisciplinary and participatory approach to research, it was possible to identify opportunities for maintaining zooprophylaxis for malaria in Mwea, through the integration of agroecosystem practices aimed at sustaining livestock systems within a broader strategy for rural development.

  1. Seasonal dynamic of the occurrence of the gregarines infection of Harpalus rufipes (Coleoptera, Carabidae in agroecosystem

    Directory of Open Access Journals (Sweden)

    D. Y. Reshetnyak

    2015-08-01

    Full Text Available Relationships in the “parasite-host” system are closely interrelated and occur at all levels from the molecular to behavioral and population ones. There are two models of realization of these relations. The first case is when the parasites are uniformly distributed in the host population. High extensiveness of invasion is accompanied by its low intensity. The second case is when a part of host population is infected with parasites, but the negative impact is manifested to the maximum extent. Invasion of the ground beetle Harpalus rufipes (De Geer, 1774, dwelling in sweet corn agroecosystems located in the vicinity of Dnipropetrovsk near Doslidnoe village, by several gregarines species is investigated in this study. H. rufipes is an abundant, ubiquitous species, living in extremely wide range of terrestrial ecosystems, with especially high populations inhabiting anthropogenically transformed environments. H. rufipes has a wide range of feeding. This species is distributed in the Central and Eastern Europe, and introduced to North America. Gregarines were found in the intestines of 20 individuals of H. rufipes from 190 (10.5%: Gregarina ovata Dufour, 1828, G. steini Berndt, 1902, G. amarae (Hammerschmidt, 1839 Frantzius, 1848, Clitellocephalus ophoni (Tuzet and Ormieres, 1956 Clopton, 2002, Torogregarina sphinx Clopton, 1998, Gigaductus macrospora Filipponi, 1948 and G. elongatus (Moriggi, 1943 Filipponi, 1948. There is high level of infestation of C. ophoni and G. steini. At the same time, not more than three species of the gregarines were localized in the beetle body. Seasonal dynamic of occurrence of the gregarines is as follows. Maximal indices of occurrence are found at the end of August (22.2% and minimal ones at the end of June (4.8%. The highest total number of gregarines (383 ind. is recorded at the end of August, the lowest one is fixed at the beginning of September (33 ind.. Indices of gregarine species dominance are as follows

  2. Allelopathic cover crop of rye for integrated weed control in sustainable agroecosystems

    Directory of Open Access Journals (Sweden)

    Vincenzo Tabaglio

    2013-02-01

    absorption capability. The insensitivity of A. theophrasti to BOA was due to reduced accumulation in seedlings. Overall, results confirm that the use of a rye cover crop in a suitable crop rotation represents a sustainable weed management practice permitting a reduction in the amount of herbicides used in agroecosystems, thus limiting the environmental risks of intensive agriculture.

  3. Rice field agroecosystem investigation : environmental and toxicological assessment; Indagine su una risaia campione: analisi ambientali e chimico-tossicologiche

    Energy Technology Data Exchange (ETDEWEB)

    Bari, A.; Minciardi, M.; Rossi, G. [ENEA, Centro Ricerche Saluggia, Vercelli (Italy). Dip. Ambiente; Bonotto, F.; Paonessa, F.; Troiani, F. [ENEA, Centro Ricerche Saluggia, Vercelli (Italy). Dip. Energia; Rosa, S. [ENEA, Centro Ricrche Casaccia, Rome (Italy). Dip. Ambiente; Cormegna, M. [Ente Nazionale Risi, Centro Ricerche sul Riso, Castello d`Agogna, Pavia (Italy)

    1995-10-01

    The rice-field agroecosystem, even if deeply anthropically determined, can be considered substitute of the plain wet lands, now almost all disappeared in the part of the territory has been considering. The aim of the research we started was the analysis and the ecological characterization of this environment and the assessment of the effects of the different agronomical practices, relating to the conservation of the biodiversity in a plain wetland. The ENEA Environmental Biology and Nature Conservation Division of Saluggia (VC) and Casaccia (Roma), in co-operation with ENEA ERG-RAD-LAB Division of Saluggia and the Rice Research Center of Castello d`Agogna (PV) associated to Rice National Society, started a preliminary research on a sample rice field, aiming to evaluate, using different methodologies, the destiny of the chemical substances (herbicides, fungicidals, heavy metals and other chemical compounds) introduced through cultivation practices or arrived by irrigation systems.

  4. Mammal assemblage of the agroecosystem constituents of the Várzea River Basin, Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Felipe Bortolotto Peters

    2010-12-01

    Full Text Available We provide recent information on the richness of mammals along the agroecosystems of the Rio da Várzea Basin, Rio Grande do Sul, Brazil. We used different field techniques to confirm the occurrence of 46 mammal species in this area. Nine species are threatened in at least one of the three “red lists” at state, national and global levels. Adding the up-to-date results obtained in the field to available data, mainly for conservation units, we present a richness of 85 species recorded for the basin. This number represents about 50% of mammals documented for Rio Grande do Sul state. The results suggest the importance of maintaining protected areas in altered regions, confirming the relevance of inventories of local fauna as a first approach to specific studies addressed to distribution, systematics, cytogenetics, physiology, population and community ecology.

  5. Hantavirus infection and habitat associations among rodent populations in agroecosystems of Panama: implications for human disease risk.

    Science.gov (United States)

    Armién, Aníbal G; Armién, Blas; Koster, Frederick; Pascale, Juan M; Avila, Mario; Gonzalez, Publio; de la Cruz, Manuel; Zaldivar, Yamitzel; Mendoza, Yaxelis; Gracia, Fernando; Hjelle, Brian; Lee, Sang-Joon; Yates, Terry L; Salazar-Bravo, Jorge

    2009-07-01

    Hantavirus cardiopulmonary syndrome (HCPS), which is caused by infection with Choclo virus, is uncommon in Panama, yet seropositivity among rural residents is as high as 60%. To clarify the environmental risk factors favoring rodent-to-human transmission, we tested serum from 3,067 rodents captured over a five-year period for antibodies against recombinant N protein of hantavirus by enzyme immunoassay and strip immunoblot. Among 220 seropositive rodents, Oligoryzomys fulvescens, the reservoir of Choclo virus, had the highest overall seroprevalence (23.5%); more abundant rodents (Zygodontomys brevicauda and Sigmodon hirsutus) had lower seroprevalences. In the mixed (combined modern and traditional) productive agroecosystem, the highest seroprevalence was among O. fulvescens captured in residences and in crops grown within 40 meters of a residence, with significantly lower seroprevalence in adjacent pasture and non-productive vegetation. Thus, crop habitats may serve as refugia for invasion into adjacent human residences and suggests several interventions to reduce human infection.

  6. Modeling of Duck Density and Complex Stocking Time in Rice-Duck Agroecosystems in Terms of Economic and Ecological Benefits

    Directory of Open Access Journals (Sweden)

    Dahong Xiong

    2014-01-01

    Full Text Available Rice-duck integrated farming is an effective step under today’s sustainable development background. To make better economic and ecological benefits, a rice-duck agroecosystem is established and kept, in which the paddy field, rice, and the duck mutually promote one another. But the duck density and complex stocking time must be rationally selected. Aiming to attain quantitative assessment and optimal selection of the duck density and complex stocking time in this kind of systems, a methodology based on proposed mathematical models in terms of comparative economic and ecological benefits is addressed. Then the models are solved by a hybrid intelligent algorithm NN-GA that integrates the Neural Networks (NN and Genetic Algorithm (GA, making use of the fitting ability in nonlinear fitness context of Neural Networks and the optimization ability of the Genetic Algorithm. Besides, numerical examples are demonstrated in order to test the proposed models. Results reveal that the methodology is reasonable and feasible.

  7. Enhancing the Feed Capacity of Horticulture Agro-Ecosystem Through Technology for Goat Production

    Directory of Open Access Journals (Sweden)

    Simon P Ginting

    2011-09-01

    Full Text Available The availability of feed and their efficiency of use throughout the year represent the most important constraint affecting the productivity of animals in any agro-ecosystems. Beside being the largest contributor to the total production cost, logistically feeds need to be available on a daily basis across the animal’s life time. In order to be competitive, goat production system must be directed toward the optimum utilization of inconventional feedstuffs such as crop residues and agro-industrial by-products. The horticulture crops provide various crop-residues and by products from the processing of its main products. These biomass are potential feedstuffs that could be used to support the production of goats. The processing of passion fruits (Passiflora edulis yield by products such as fruit shells and seeds. These products are good energy and protein sources for growing goats. Oriental radish (Raphanus sativus by-products composed by damaged root parts and culls have high digestible energy and low ether extract content, but have very high moisture content. The pineapple by-products composed by the peel and bagasse of the fruit could be used as energy source for goats. Other horticulture by-products or residues such as citrus pulp, abandoned citrus fruit, forages from Ipomea batatas are of great potential as feeds for goat production. Preserving technology like ensiling could be implemented in utilising those biomass categorized as wet by-products such as pineapple and oriental radish by-products. The technology of complete feed is an effective means in utilizing some of those products with relatively low palatability or to increase its inclusion level in diets. Introducing shade-tolerant forage species as intercrops such as Stenotaphrum secundatum, Brachiaria humidicola and Arachis pintoi in the citrus plantation should increase feed capacity of the area. The multi-purpose trees such as Indigofera sp. and Calliandra calothyrsus both are

  8. Separating Autotrophic and Heterotrophic Contributions to Soil Respiration in Maize-Based Agroecosystems Using Stable Carbon Isotope Ratio Mass Spectrometry.

    Science.gov (United States)

    Amos, B.; Walters, D. T.; Madhavan, S.; Arkebauer, T. J.; Scoby, D. L.

    2005-12-01

    Any effort to establish a carbon budget for a growing crop by means of a thorough accounting of all C sources and sinks will require the ability to discriminate between autotrophic and heterotrophic contributions to soil surface CO2 flux. Autotrophic soil respiration (Ra) is defined as combined root respiration and the respiration of soil microorganisms residing in the rhizosphere and using root-derived carbohydrates as an energy source, while heterotrophic respiration (Rh) is defined as the respiration of soil microorganisms and macroorganisms not directly under the influence of the live root system and using SOM as an energy source. We partition soil surface CO2 flux into its autotrophic and heterotrophic components by combining root exclusion with stable carbon isotope techniques in production scale (~65 ha) maize-based agroecosystems. After flux measurements, small chambers are placed on collars in both root excluded shields and in non-root excluded soil, ambient headspace CO2 is removed using a soda lime trap, and soil-respired C is allowed to collect in the chambers. Soil respiration samples are then collected in 12mL evacuated exetainers and analyzed for δ13C by means of a Finnigan Delta-S isotope ratio mass spectrometer interfaced with a Thermo Finnigan GasBench II and a cryogenic trap to increase CO2 concentration. These δ13C measurements were made throughout the 2005 growing season in maize fields representing three agroecosystems: irrigated continuous maize, irrigated maize-soybean rotation, and rainfed maize soybean rotation. Estimates of autotrophic and heterotrophic soil respiration along with other results of this study will be presented.

  9. Interannual Variations of the Carbon Footprint and Carbon Eco-efficiency in Agro-ecosystem of Beijing, China

    Directory of Open Access Journals (Sweden)

    TIAN Zhi-hui

    2015-12-01

    Full Text Available Suburban farmland ecosystems are known to be affected by intensive land use/cover change (LUCC during the process of urbanization in Beijing. We investigated inter-annual changes in carbon sequestration, source, footprint, and eco-efficiency from 2004 to 2012 in the agro-ecosystem of suburban Beijing. Our findings indicated that: (1 Carbon sink increased 2.8 percent annually and the average annual carbon storage amount was 1 058 200 t, with food crops constituting the highest proportion at 80.4% of carbon storage in farmland ecosystems, of which maize contributed 68.5% as the largest constituent; (2 Carbon emission in the system showed a gradually decreasing trend, with agricultural chemicals as significant contributors. The annual average carbon emission was 276 000 tons in the Beijing farmland ecosystem, and decreased approximately 1.3 percent per year. The largest amount of carbon emissions came from agricultural chemicals at 85.4%, of which nitrogen fertilizer was the biggest contributor at 83.7%; ( 3 The carbon footprint also showed a decreasing trend along with an ecological surplus of carbon. The average carbon footprint was 5.71 hm2 in the Beijing farmland ecosystem with decreasing rate at 5.5% annually; however, the carbon surplus showed a downward trend due to reduction in the amount of arable land; (4 Finally, the increasing carbon sink capacity led to higher carbon eco-efficiency, with an annual average of 3.854 kg C·kg-1 CE, carbon sequestration was greater than the amount of carbon released. In summary, the agro-ecosystem in suburban Beijing has sustained a relatively high carbon eco-efficiency, and agricultural production continues to have high sustainability potential.

  10. Options for using Landsat and RapidEye satellite images aiming the water productivity assessments in mixed agro-ecosystems

    Science.gov (United States)

    de C. Teixeira, Antônio H.; Leivas, Janice F.; Bayma-Silva, Gustavo

    2016-10-01

    For water productivity (WP) assessments, the SAFER (Surface Algorithm for Evapotranspiration Retrieving) algorithm for evapotranspiration (ET) and the Monteith's light use efficiency (LUE) model for biomass production (BIO), were applied to Landsat and RapidEye satellite images, in the Brazilian semiarid region, inside the dry season of 2011, in a mixture of irrigated and rainfed agro-ecosystems. Firstly, with the Landsat image, the methodology from which the surface temperature (T0) is derived as a residue in the radiation balance was tested. Low differences were detected, being Landsat ET with the thermal band averaged 0.9 +/- 1.5 mm d-1, while without it the mean value was 0.8 +/- 1.5 mm d-1. The corresponding Landsat BIO values were respectively 28 +/- 59 and 28 +/- 58 kg ha-1 d-1, resulting in mean WP of 1.3 +/- 1.3 kg m-3, in both cases. After having confidence on the residual methodology for retrieving T0 it was applied to the RapidEye image, resulting in average pixel values for ET, BIO and WP of 0.6 +/- 1.5 mm d-1, 26 +/- 58 kg ha-1 d-1 and 0.9 +/- 1.3 kg m-3, representing 75%, 93% and 69% of the Landsat ones obtained without the thermal band. In addition, the Surface Resistance Algorithm (SUREAL) was used to classify the agro-ecosystems into irrigated crops and natural vegetation by using the RapidEye image. The incremental values for ET, BIO and WP in 2011 were 2.0 +/- 1.3 mm d-1, 88 +/- 87 kg ha d-1 and 2.5 +/- 0.6 kg m-3, respectively, as a result of the replacement of the natural species by crops.

  11. Carbon fluxes and the carbon budget in agroecosystems on agro-gray soils of the forest-steppe in the Baikal region

    Science.gov (United States)

    Pomazkina, L. V.; Sokolova, L. G.; Zvyagintseva, E. N.

    2013-06-01

    Field studies devoted to the transformation of the carbon cycle in agroecosystems on agro-gray soils (including soils contaminated with fluorides from aluminum smelters) in dependence on the changes in the hydrothermic conditions were performed for the first time within the framework of the long-term (1996-2010) soil monitoring in the forest-steppe zone of the Baikal region. The major attention was paid to the impact of the environmental factors on the synthesis and microbial destruction of organic carbon compounds. Certain differences in the fluxes and budget of carbon were found for the plots with cereal and row crops and for the permanent and annual fallow plots. The adverse effect of fluorides manifested itself in the enhanced C-CO2 emission under unfavorable water and temperature conditions. The long-term average C-CO2 emission from the soils contaminated with fluorides in agroecosystems with wheat after fallow was higher than that from the uncontaminated soil (179 and 198 g of C/m2, respectively) and higher than that in the agroecosystems with a potato monoculture (129 and 141 g of C/m2, respectively). At the same time, no significant variations in the content of the carbon of the microbial biomass (Cmicr) in dependence on the environmental factors were found. The utilization of carbon for respiration and for growth of the soil microorganisms on the contaminated soil were unbalanced in particular years and for the entire period of the observations. The ratio between the fluxes of the net mineralized and re-immobilized carbon was used for the integral assessment of the functioning regime of the agroecosystems and the loads on them. Independently from the soil contamination with fluorides, the loads on the agroecosystems with wheat were close to the maximum permissible value, and the loads on the agroecosystems with potatoes were permissible. It was shown that the carbon deficit in the uncontaminated soils was similar under the wheat and potatoes (-30 and -28 g

  12. Participation of the fossil energy in cotton agro-ecosystem in family agricultural explorations; Participacao da energia fossil no agroecossistema algodao em exploracoes agricolas familiares

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, Osmar de Carvalho; Cabrera Romero, Maria Gloria [Universidade Estadual Paulista (UNESP), Botucatu, SP (Brazil). Fac. de Ciencias Agronomicas

    2006-07-01

    With the objective of presenting the participation of the several energy sources employees in the cotton agro-ecosystem, this work is constituted in a contribution regarding the subject of the sustain grow.As the focal point of this research, family exploitation is analyzed, with the use of the categorization done by the National Program for Strengthening Family Agriculture - ('Programa Nacional de Fortalecimento da Agricultura Familiar - PRONAF). Use was made of primary and secondary data from three family exploitations in the municipality of Leme/SP, Brazil. To construct the energy expenditure structure of the cotton agro-ecosystem, the mean values obtained were considered, since these agriculturalists present the same technical itinerary and are within the typification proposed in this study. The results were presented by the energy expenditure structure by type, source, form of energy. Considering the cotton agro-ecosystem from the technical itinerary presented, the input energy equal to 51.961,63 MJ . ha{sup -1} was observed, with a participation of 34,21% and 65,79% of the direct and indirect energy respectively. The studied agro ecosystem fundamentally depended on the industrial source of energy, particularly insecticides (39,71%) and chemical fertilizers (19,88%) and fossil sources (33,80%). It was verified like this that the dependence of the industrial energy and of the fossil energy in the cotton agro ecosystem. In that way, we suggest himself the search of the use of another types of energy that they allow the energy sustainability of this agro-ecosystems in family agricultural systems. (author)

  13. 农田生物多样性对昆虫的生态调控作用%Effects of ecological regulation of biodiversity on insects in agroecosystems

    Institute of Scientific and Technical Information of China (English)

    周海波; 陈巨莲; 程登发; Frederic Francis; 刘勇; 孙京瑞

    2012-01-01

    With the serious problems of herbivorous insect outbreaks and species extinction caused by monocultured crops in large areas, the wide and heavy use of chemical pesticides has made the destruction and instability of agro-ecosystems to rise. Thus, based on the relationships among biodiversity-agroecosystem-herbivorous insect, studying the impacts of conservation and application of biodiversity on pest control and developing new techniques for ecological manipulation in agroecosystems have become the highlights of research on sustainable agriculture. This paper reviewed the importance and ecological effects of biodiversity on herbivorous insects in agroecosystems, and the prospects and applications of biodiversity in agricultural cultivation was further discussed.%随着农田作物的单一性种植,植食性昆虫暴发、物种流失等问题日益突出,化学农药大量应用于作物有害生物的防治更加剧了对农田生态系统的破坏和不稳定性.因此,从生物多样性-农田生态系统-植食性昆虫的相互关系入手,探讨生物多样性的保护及其在农业有害生物防控上的应用,回归农田生态系统动态平衡的生态调控举措,成为可持续发展农业领域中研究的焦点之一.本文综述了农田生物多样性对昆虫生态影响的重要性及其生态功能,进一步阐述了农田生物多样性在农业生产中的应用及前景.

  14. Adapting to change in the Andean Highlands: Practices and strategies to address climate and market risks in vulnerable agro-ecosystems

    OpenAIRE

    University of Missouri

    2007-01-01

    Metadata only record The project is a research and development collaboration between rural communities in the Altiplano and high valleys of Bolivia and Peru, universities and non governmental organizations in the region and the US, and institutions that formulate policy. It will strengthen the capacity of these communities and institutions to conduct research and to develop strategies to adapt to change, to reduce vulnerability and enhance biodiversity of their agro-ecosystems. Our Goal is...

  15. The Sahelian agro-ecosystem vulnerability to an acceleration of ice-sheet melting during the 21st century

    Science.gov (United States)

    Defrance, Dimitri; Ramstein, Gilles; Charbit, Sylvie; Sultan, Benjamin; Dumas, Christophe; Vrac, Mathieu; Swingedouw, Didier; Gemenne, François; Alvarez-Solas, Jorge; Vanderlinden, Jean-Paul

    2016-04-01

    During the 20th century, Sahelian drought episodes like those between 1972 and 1982 showed the vulnerability of the Sahelian agro-ecosystem provoking significant intraregional southward human migrations, to or near the coast. According to the latest IPCC report, the Sahel could become increasingly impacted by climate change during the 21st century because of a lagged and shorter rainfall season having the potential to induce a drastic destabilization of the Sahelian agro-ecosystem and to heavily impact the population. Such effects could be further amplified by a net increase of the Sahelian population. Drastic climate changes over tropical areas also occurred in the past: weakening of the West African Monsoon and megadrought Sahelian episodes have been reported with a close correspondence between the large rainfall decrease and the massive freshwater discharges following ice-sheet melting or iceberg surges. During the last decades a continuous acceleration of ice-sheet mass loss has been observed and post IPCC-AR5 studies suggest the ice-sheet contribution to future sea-level rise could be revised upward due partly to the lack of an accurate representation of ice-ocean interactions. The release of freshwater discharge in response to ice-sheet instability could have large consequences on the most vulnerable regions, such as the tropical areas. To investigate the impacts of large ice-sheet instability during the 21st century, we first explore the climatic signature of Greenland or Antarctic ice-sheet collapse scenarios corresponding to 0.5 to 1.5 meter of sea-level rise, superimposed to the RCP8.5 scenario. We show that a freshwater discharge coming from Greenland melting induces a significant decrease of summer monsoon rainfall, that may lead to changes in agricultural practices. Combined with increasing demography, this has the potential to induce important human migration flows. Without adaptation measures, we estimate that tens to hundreds million people could be

  16. [Characteristics of evapotranspiration and crop coefficient of agroecosystems in semi-arid area of Loess Plateau, Northwest China].

    Science.gov (United States)

    Yang, Fu-Lin; Zhang, Qiang; Wang, Run-Yuan; Wang, Sheng; Yue, Ping; Wang, He-Ling; Zhao, Hong

    2013-05-01

    Evapotranspiration (ET) is an important component of ground surface energy balance and water balance, and closely related to water cycle. By using eddy covariance technique, this paper studied the ET characteristics of agroecosystems in the semi-arid area of Loess Plateau in growth season (from April to September), 2010, and analyzed the relationships between crop coefficient and environmental factors. During the observation period, the diurnal variation of latent heat flux (LE) in each month was similar to single-peak curve, and the peak value (151.4 W x m(-2)) occurred in August. The daytime energy partitioning manner showed a significant seasonal variation, with LE/R(n) heat flux) from April to June, and LE/R(n) > H/R(n) from July to September. The daily ET rate also showed a significant seasonal variation, with the maximum of 4.69 mm x d(-1). The wind speed (W(s)), relative humidity (RH), soil water content (theta), and atmospheric vapor pressure deficit (D) were the major factors affecting the crop coefficient K(c) which was exponentially decreased with increasing W(s), exponentially increased with increasing RH and theta, and linearly decreased with increasing D.

  17. Evaluation of a regional air-quality model with bidirectional NH3 exchange coupled to an agroecosystem model

    Directory of Open Access Journals (Sweden)

    J. O. Bash

    2013-03-01

    Full Text Available Atmospheric ammonia (NH3 is the primary atmospheric base and an important precursor for inorganic particulate matter and when deposited NH3 contributes to surface water eutrophication, soil acidification and decline in species biodiversity. Flux measurements indicate that the air–surface exchange of NH3 is bidirectional. However, the effects of bidirectional exchange, soil biogeochemistry and human activity are not parameterized in air quality models. The US Environmental Protection Agency's (EPA Community Multiscale Air-Quality (CMAQ model with bidirectional NH3 exchange has been coupled with the United States Department of Agriculture's (USDA Environmental Policy Integrated Climate (EPIC agroecosystem model. The coupled CMAQ-EPIC model relies on EPIC fertilization timing, rate and composition while CMAQ models the soil ammonium (NH4+ pool by conserving the ammonium mass due to fertilization, evasion, deposition, and nitrification processes. This mechanistically coupled modeling system reduced the biases and error in NHx (NH3 + NH4+ wet deposition and in ambient aerosol concentrations in an annual 2002 Continental US (CONUS domain simulation when compared to a 2002 annual simulation of CMAQ without bidirectional exchange. Fertilizer emissions estimated in CMAQ 5.0 with bidirectional exchange exhibits markedly different seasonal dynamics than the US EPA's National Emissions Inventory (NEI, with lower emissions in the spring and fall and higher emissions in July.

  18. Evaluation of a regional air-quality model with bidirectional NH3 exchange coupled to an agroecosystem model

    Science.gov (United States)

    Bash, J. O.; Cooter, E. J.; Dennis, R. L.; Walker, J. T.; Pleim, J. E.

    2013-03-01

    Atmospheric ammonia (NH3) is the primary atmospheric base and an important precursor for inorganic particulate matter and when deposited NH3 contributes to surface water eutrophication, soil acidification and decline in species biodiversity. Flux measurements indicate that the air-surface exchange of NH3 is bidirectional. However, the effects of bidirectional exchange, soil biogeochemistry and human activity are not parameterized in air quality models. The US Environmental Protection Agency's (EPA) Community Multiscale Air-Quality (CMAQ) model with bidirectional NH3 exchange has been coupled with the United States Department of Agriculture's (USDA) Environmental Policy Integrated Climate (EPIC) agroecosystem model. The coupled CMAQ-EPIC model relies on EPIC fertilization timing, rate and composition while CMAQ models the soil ammonium (NH4+) pool by conserving the ammonium mass due to fertilization, evasion, deposition, and nitrification processes. This mechanistically coupled modeling system reduced the biases and error in NHx (NH3 + NH4+) wet deposition and in ambient aerosol concentrations in an annual 2002 Continental US (CONUS) domain simulation when compared to a 2002 annual simulation of CMAQ without bidirectional exchange. Fertilizer emissions estimated in CMAQ 5.0 with bidirectional exchange exhibits markedly different seasonal dynamics than the US EPA's National Emissions Inventory (NEI), with lower emissions in the spring and fall and higher emissions in July.

  19. Evaluation of four sampling techniques for surveillance of Culex quinquefasciatus (Diptera: Culicidae) and other mosquitoes in African rice agroecosystems.

    Science.gov (United States)

    Muturi, Ephantus J; Mwangangi, Joseph; Shililu, Josephat; Muriu, Simon; Jacob, Benjamin; Mbogo, Charles M; John, Githure; Novak, Robert

    2007-05-01

    Field studies were conducted in a rice, Oryza sativa L., agroecosystem in Mwea Kenya to compare the efficiency of CO2-baited Centers for Disease Control (CDC) light traps against nonbaited CDC light traps and gravid traps against oviposition traps in outdoor collection of Culex quinquefasciatus Say (Diptera: Culicidae) and other mosquitoes. Collectively, 21 mosquito species from the genera Culex, Anopheles, Mansonia, Ficalbia, and Aedes were captured during the 10-wk study period. Cx. quinquefasciatus was the predominant species in all trap types with proportions ranging from 57% in the nonbaited CDC light traps to 95% in the gravid traps. Significantly higher numbers of Cx. quinquefasciatus and Culex annulioris Theobald were collected in the CO2-baited CDC light traps than in the nonbaited CDC light traps, but the numbers of other mosquito species, including malaria vectors Anopheles arabiensis Patton and Anopheles funestus Giles did not differ significantly between the two trap types. More Cx. quinquefasciatus females were collected in grass infusion-baited gravid traps than egg rafts of this species in oviposition traps containing the same infusion. Although most mosquitoes captured in CO,-baited and nonbaited CDC light traps were unfed, most of those collected in gravid traps were gravid. From these findings, it is concluded that at least in the rice-growing area of Mwea Kenya, CO2-baited CDC light traps in conjunction with gravid traps can be used in monitoring of Cx. quinquefasciatus both for control and disease surveillance.

  20. Is the emergence of fungal resistance to medical triazoles related to their use in the agroecosystems? A mini review.

    Science.gov (United States)

    Ribas E Ribas, Aícha Daniela; Spolti, Pierri; Del Ponte, Emerson Medeiros; Donato, Katarzyna Zawada; Schrekker, Henri; Fuentefria, Alexandre Meneghello

    Triazole fungicides are used broadly for the control of infectious diseases of both humans and plants. The surge in resistance to triazoles among pathogenic populations is an emergent issue both in agriculture and medicine. The non-rational use of fungicides with site-specific modes of action, such as the triazoles, may increase the risk of antifungal resistance development. In the medical field, the surge of resistant fungal isolates has been related to the intensive and recurrent therapeutic use of a limited number of triazoles for the treatment and prophylaxis of many mycoses. Similarities in the mode of action of triazole fungicides used in these two fields may lead to cross-resistance, thus expanding the spectrum of resistance to multiple fungicides and contributing to the perpetuation of resistant strains in the environment. The emergence of fungicide-resistant isolates of human pathogens has been related to the exposure to fungicides used in agroecosystems. Examples include species of cosmopolitan occurrence, such as Fusarium and Aspergillus, which cause diseases in both plants and humans. This review summarizes the information about the most important triazole fungicides that are largely used in human clinical therapy and agriculture. We aim to discuss the issues related to fungicide resistance and the recommended strategies for preventing the emergence of triazole-resistant fungal populations capable of spreading across environments.

  1. Impacts of transgenic poplar-cotton agro-ecosystems upon target pests and non-target insects under field conditions.

    Science.gov (United States)

    Zhang, D J; Liu, J X; Lu, Z Y; Li, C L; Comada, E; Yang, M S

    2015-07-27

    Poplar-cotton agro-ecosystems are the main agricultural planting modes of cotton fields in China. With increasing acres devoted to transgenic insect-resistant poplar and transgenic insect-resistant cotton, studies examining the effects of transgenic plants on target and non-target insects become increasingly important. We systematically surveyed populations of both target pests and non-target insects for 4 different combinations of poplar-cotton eco-systems over 3 years. Transgenic Bt cotton strongly resisted the target insects Fall webworm moth [Hyphantria cunea (Drury)], Sylepta derogata Fabrieius, and American bollworm (Heliothis armigera), but no clear impact on non-target insect cotton aphids (Aphis gossypii). Importantly, intercrops containing transgenic Pb29 poplar significantly increased the inhibitory effects of Bt cotton on Fall webworm moth in ecosystem IV. Highly resistant Pb29 poplar reduced populations of the target pests Grnsonoma minutara Hubner and non-target insect poplar leaf aphid (Chaitophorus po-pulialbae), while Fall webworm moth populations were unaffected. We determined the effects of Bt toxin from transgenic poplar and cotton on target and non-target pests in different ecosystems of cotton-poplar intercrops and identified the synergistic effects of such combinations toward both target and non-target insects.

  2. Integrated evaluation of energy use, greenhouse gas emissions and global warming potential for sugar beet (Beta vulgaris) agroecosystems in Iran

    Science.gov (United States)

    Yousefi, Mohammad; Khoramivafa, Mahmud; Mondani, Farzad

    2014-08-01

    The main aim of this study was to determine and discuss the aggregate of energy use and greenhouse gas emission (CO2, N2O, and CH4) for sugar beet agroecosystems in western of Iran. For this propose data was collected by using questionnaires and face to face interview with 50 farmers. Results showed that total inputs and output energy were 49517.2 and 1095360.0 MJ ha-1, respectively. Energy use efficiency was 22.12. Total CO2, N2O and CH4 emissions due to chemical inputs were 2668.35, 22.92 and 3.49 kg, respectively. In sugar beet farms total global warming potential (GWPs) was 9847.77 kg CO2eq ha-1. In terms of CO2 equivalents, 27% of the GWPs come from CO2, 72% from N2O, and 1% from CH4. In this research input and output carbon were 29340.0 and 2678.6 kg C ha-1, respectively. Hence, carbon efficiency ratio was 10.95.

  3. Evaluation on potential of wild hosts as trap plants for managing gramineous stemborers in maize based-agroecosystem.

    Science.gov (United States)

    Yewhalaw, Delenasaw; Getu, Emana; Seyoum, Emiru

    2008-02-01

    As part of habitat management system to control cereal stemborers, various wild hosts used as trap plants were studied during the dry season from November 2003 to March 2004 at Melkassa, central Ethiopia. Five wild hosts of the family Poaceae [Pennisetum purpurum (Schumach), Sorghum vulgare variety sudanense (Pers.), Panicum coloratum L., Sorghum arundinaceum Stapf, and Hyperrhania rufa (Nees)] were evaluated as trap plants in maize, Zea mays L.,-based agroecosystem. The results of the study showed that maize plots surrounded by all tested wild hosts had significantly lower mean percentage of foliage damage and stemborer density than maize monocrop plots 15 m away from the treatment blocks. Interestingly, mean foliar damage and stemborer density between maize plots surrounded by wild hosts and maize monocrop plots within the treatment blocks was not significant. Percentage of tunneled stalks was significantly greater in maize monocrop plots 15 m away from the treatment blocks than in maize plots surrounded by all tested wild host plant species. Moreover, the highest mean percentage of parasitism (62%) of Chilo partellus (Swinhoe) by Cotesia flavipes (Cameron) was recorded in maize plots surrounded by P. purpureum. Therefore, the findings revealed that these wild hosts have considerable merit to be used as trap plants in the development of strategies for managing cereal stemborers in maize crops.

  4. Eco-physiological adaptation of the land snail Achatina achatina (Gastropoda: Pulmonata in tropical agro-ecosystem

    Directory of Open Access Journals (Sweden)

    Christian O. Chukwuka

    2014-03-01

    Full Text Available The survival of land snails in an adverse environmental condition depends on the integral physiological, morphological and behavioural adaptations. These adaptations are essential in understanding the species-specific habitat requirements and in predicting their environmental responses. In this study, the monthly and the periodic patterns of eco-physiological adaptation of land snail, Achatina achatina in Nsukka tropical agro-ecosystem were assessed from December 2012 to July 2013. Standard methods were employed in sampling the land snail and determination of the water content, biochemical fuel reserves and enzyme concentrations of the samples. The present results showed that lipids were high at the beginning of aestivation and depleted as the aestivation progressed. Glycogen was significantly low throughout the aestivation months (December–March and increased in the active months (April–July. Protein content recorded a definite pattern all through the months studied. Catabolism of lactate and a decrease in activity of LDH during aestivation and substantial increase upon activation were observed. Data showed that transaminase and aspartate enzymes depleted during the aestivation months indicating that the snails may have developed potential cell injury due to oxidative stress and thermal heat. A disassociation between the physiological responses and climatic data was recorded. The physiological adaptation of A. achatina ensures regular adjustment under extreme conditions and compensates for its metabolic regulation in the tropics. It is concluded that survival of A. achatina is not environmentally predicted; rather it depends on the species-specific inherent process in predicting responses for survival.

  5. Review of agro-ecosystem services and their values%农田生态系统服务及其价值的研究进展

    Institute of Scientific and Technical Information of China (English)

    谢高地; 肖玉

    2013-01-01

    农田生态系统在人类控制下已逐渐演变成了提供农产品的集约化生产系统.尽管与自然生态系统相比,农田生态系统服务功能有所下降,但其在提供农产品的同时还在向人类提供大量的生态服务.近年来,生态系统服务稀缺性变得越来越突出,农田生态系统的多功能性受到了空前的重视.本文首先明确了农田生物多样性是农田提供多种生态系统服务的基础,然后回顾了2000年以来国内外农田生态系统服务及其价值化领域取得的主要研究进展,包括对农田产品供给、碳汇、土壤保持和养分循环、水调节等功能的评价以及对农田生态系统服务及其价值化的综合研究.与此同时,我们也应该注意到农业生产还对人类社会和自然环境产生了各种消极影响,认识到权衡农田生态系统在农业生产中的各项利弊的重要性.通过对比不同农业生产模式对农田生态系统服务供给的影响,提出未来发展多功能农业将是实现农田对人类福祉最大化的重要方向.最后,文章指出我国发展多功能农业的主要措施是:(1)确保18亿亩耕地在空间上的存在;(2)与森林、草地、湿地、水域等其他自然生态系统在空间上合理配置;(3)在农业区域充分发展以观光休闲功能为主的休闲农业,实现农田生态系统社会文化价值;(4)逐步实施农业生态补偿.%Agro-ecosystem has become an integrated crop production system with significant human disturbances.Compared with natural ecosystems,the crop production function of agro-ecosystem has intensified while impairing other ecosystem services such as gas/water regulation,soil conservation and biodiversity maintenance.In recent years,agro-ecosystem services have become more and more scarce because of large demand by the rapid global development.This has resulted in an increasing concern about the values and services of agro-ecosystems across the globe.This study

  6. Unravelling trophic subsidies of agroecosystems for biodiversity conservation: Food consumption and nutrient recycling by waterbirds in Mediterranean rice fields

    Energy Technology Data Exchange (ETDEWEB)

    Navedo, Juan G., E-mail: jgnavedo@uach.cl [Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Facultad de Ciencias, Campus Isla Teja, 5090000 Valdivia (Chile); Conservation Biology Research Group, Universidad de Extremadura, Avda. Elvas s/n, 06002 Badajoz (Spain); Hahn, Steffen [Department Bird Migration, Swiss Ornithological Institute, Seerose 1, 6204 Sempach (Switzerland); Parejo, Manuel; Abad-Gómez, José M. [Conservation Biology Research Group, Universidad de Extremadura, Avda. Elvas s/n, 06002 Badajoz (Spain); Gutiérrez, Jorge S. [Conservation Biology Research Group, Universidad de Extremadura, Avda. Elvas s/n, 06002 Badajoz (Spain); Department of Marine Ecology, Royal Netherlands Institute for Sea Research (NIOZ), PO Box 59, 1790 AB Den Burg, Texel (Netherlands); Villegas, Auxiliadora; Sánchez-Guzmán, Juan M.; Masero, José A. [Conservation Biology Research Group, Universidad de Extremadura, Avda. Elvas s/n, 06002 Badajoz (Spain)

    2015-04-01

    Waterbirds can reallocate a considerable amount of nutrients within agricultural fields and between agriculture sites and wetlands. However their effects on biogeochemical cycles have rarely been quantified. We estimated bird numbers, diet (from stable isotope analysis), food supply, and the food consumption on rice fields by overwintering waterbirds in one of the most important areas for rice production in southwestern Europe and a key area for various migrating and resident waterbird species. Herein, we modelled the nutrient (N and P) recycling in rice fields, and their transport to reservoirs. The energy consumption by waterbirds (96,605 ± 18,311 individuals) on rice fields during winter averaged at 89.9 ± 39.0 kJ·m{sup −2}, with its majority (89.9%) belonging to foraging on rice seeds. Thus, the birds removed about 26% of rice seeds leftover after harvest (estimated in 932.5 ± 504.7 seeds·m{sup −2} in early winter) wherein common cranes and dabbling ducks (four species) were the most important consumers. Waterbirds foraging and roosting in the rice fields recycled more than 24.1 (1.0 kg·ha{sup −1}) of N and an additional 5.0 tons (0.2 kg·ha{sup −1}) of P in the Extremadura's rice fields during winter. Additionally, we estimated that 2.3 tons of N and 550 kg of P were removed from rice fields and transported to reservoirs. The seasonal foraging of wildlife should result in a direct benefit for rice farmers by improving nutrient recycling through defecation by waterbirds with respect to artificial fertilisation. Additionally, rice fields located in the cranes' core wintering areas can provide sufficient food supply to induce habitat shift from their traditional wintering habitat in ‘dehesas’ to rice fields, which causes indirect socioeconomic benefit through reduced acorn consumption by cranes. Our modelling approach may thus be especially helpful for management decisions regarding rice agroecosystems in areas which are also important

  7. Hypothenemus hampei (Coleoptera: Curculionidae) and its interactions with Azteca instabilis and Pheidole synanthropica (Hymenoptera: Formicidae) in a shade coffee agroecosystem.

    Science.gov (United States)

    Jiménez-Soto, Estelí; Cruz-Rodríguez, Juan A; Vandermeer, John; Perfecto, Ivette

    2013-10-01

    The coffee berry borer is currently the most important insect pest of coffee worldwide. In shaded coffee farms such as Finca Irlanda in Chiapas, Mexico, natural enemies limit coffee berry borer and potentially prevent outbreaks. This research aimed to determine the effect of ants on coffee berry borer damage and to describe behaviors of Azteca instabilis F. Smith and Pheidole synanthropica (Longino 2009) when encountering the coffee berry borer. To these ends, an ant survey was conducted in a 2,500-m(2) plot within the farm. A 4- by 4-m coordinate system was established, and the coffee plant or shade tree closest to the coordinate point was sampled using tuna fish for a total of 168 coffee plants and 46 shade trees sampled. In addition, up to 100 berries were harvested from 138 coffee plants to measure damage and verify the presence of the coffee berry borer. Behavior was determined in the field by placing live coffee berry borer adults on berries and video recording all attacks. Results showed that plants with ants had less percentage of damaged berries and shorter coffee berry borer galleries than plants without ants. However, the length of galleries in plants with A. instabilis showed no significant differences from plants without ants. P. synanthropica was observed carrying coffee berry borer to the nest in 50% of the cases, whereas A. instabilis threw coffee berry borer off of the coffee plant in 79% of the cases. Results indicate that the presence of these species of ants reduce coffee berry borer damage and suggest that different behaviors could explain the pattern of coffee berry borer attack in this agroecosystem.

  8. Greenhouse Gas Emissions from Agro-Ecosystems and Their Contribution to Environmental Change in the Indus Basin of Pakistan

    Institute of Scientific and Technical Information of China (English)

    M. Mohsin IQBAL; M. Arif GOHEER

    2008-01-01

    There is growing concern that increasing concentrations of greenhouse gases in the atmosphere have been responsible for global warming through their effect on radiation balance and temperature. The magnitude of emissions and the relative importance of different sources vary widely, regionally and locally. The Indus Basin of Pakistan is the food basket of the country and agricultural activities are vulnerable to the effects of global warming due to accelerated emissions of GHGs. Many developments have taken place in the agricultural sector of Pakistan in recent decades in the background of the changing role of the government and the encouragement of the private sector for investment in new ventures. These interventions have considerable GHG emission potential. Unfortunately, no published information is currently available on GHC concentrations in the Indus Basin to assess their magnitude and emission trends. The present study is an attempt to estimate GHG (CO2, CH4 and N2O) emissions arising from different agro-ecosystems of Indus Basin. The GHGs were estimated mostly using the IPCC Guidelines and data from the published literature. The results showed that CH4 emissions were the highest (4.126 Tg yr-1) followed by N2O (0.265 Tg yr-1) and CO2 (52.6 Tg yr-1). The sources of CH4 are enteric fermentation, rice cultivation and cultivation of other crops. N2O is formed by microbial denitrification of NO3 produced from applied fertilizer-N on cropped soils or by mineralization of native organic matter on fallow soils. CO2 is formed by the burning of plant residue and by soil respiration due to the decomposition of soil organic matter.

  9. Distinct responses of soil microbial communities to elevated CO2 and O3 in a soybean agro-ecosystem.

    Science.gov (United States)

    He, Zhili; Xiong, Jinbo; Kent, Angela D; Deng, Ye; Xue, Kai; Wang, Gejiao; Wu, Liyou; Van Nostrand, Joy D; Zhou, Jizhong

    2014-03-01

    The concentrations of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) have been rising due to human activities. However, little is known about how such increases influence soil microbial communities. We hypothesized that elevated CO2 (eCO2) and elevated O3 (eO3) would significantly affect the functional composition, structure and metabolic potential of soil microbial communities, and that various functional groups would respond to such atmospheric changes differentially. To test these hypotheses, we analyzed 96 soil samples from a soybean free-air CO2 enrichment (SoyFACE) experimental site using a comprehensive functional gene microarray (GeoChip 3.0). The results showed the overall functional composition and structure of soil microbial communities shifted under eCO2, eO3 or eCO2+eO3. Key functional genes involved in carbon fixation and degradation, nitrogen fixation, denitrification and methane metabolism were stimulated under eCO2, whereas those involved in N fixation, denitrification and N mineralization were suppressed under eO3, resulting in the fact that the abundance of some eO3-supressed genes was promoted to ambient, or eCO2-induced levels by the interaction of eCO2+eO3. Such effects appeared distinct for each treatment and significantly correlated with soil properties and soybean yield. Overall, our analysis suggests possible mechanisms of microbial responses to global atmospheric change factors through the stimulation of C and N cycling by eCO2, the inhibition of N functional processes by eO3 and the interaction by eCO2 and eO3. This study provides new insights into our understanding of microbial functional processes in response to global atmospheric change in soybean agro-ecosystems.

  10. Malaria vector control practices in an irrigated rice agro-ecosystem in central Kenya and implications for malaria control

    Directory of Open Access Journals (Sweden)

    Ng'ang'a Peter N

    2008-07-01

    Full Text Available Abstract Background Malaria transmission in most agricultural ecosystems is complex and hence the need for developing a holistic malaria control strategy with adequate consideration of socio-economic factors driving transmission at community level. A cross-sectional household survey was conducted in an irrigated ecosystem with the aim of investigating vector control practices applied and factors affecting their application both at household and community level. Methods Four villages representing the socio-economic, demographic and geographical diversity within the study area were purposefully selected. A total of 400 households were randomly sampled from the four study villages. Both semi-structured questionnaires and focus group discussions were used to gather both qualitative and quantitative data. Results The results showed that malaria was perceived to be a major public health problem in the area and the role of the vector Anopheles mosquitoes in malaria transmission was generally recognized. More than 80% of respondents were aware of the major breeding sites of the vector. Reported personal protection methods applied to prevent mosquito bites included; use of treated bed nets (57%, untreated bed nets (35%, insecticide coils (21%, traditional methods such as burning of cow dung (8%, insecticide sprays (6%, and use of skin repellents (2%. However, 39% of respondents could not apply some of the known vector control methods due to unaffordability (50.5%, side effects (19.9%, perceived lack of effectiveness (16%, and lack of time to apply (2.6%. Lack of time was the main reason (56.3% reported for non-application of environmental management practices, such as draining of stagnant water (77% and clearing of vegetations along water canals (67%. Conclusion The study provides relevant information necessary for the management, prevention and control of malaria in irrigated agro-ecosystems, where vectors of malaria are abundant and disease

  11. Can climate change jeopardize predator control of invasive herbivore species? A case study in avocado agro-ecosystems in Spain.

    Science.gov (United States)

    Montserrat, Marta; Sahún, Rosa María; Guzmán, Celeste

    2013-02-01

    Climate change is one of the most important factors affecting the phenology, distribution, composition and diversity of organisms. In agricultural systems many pests and natural enemies are arthropods. As poikilotherm organisms, their body temperature is highly dependent on environmental conditions. Because higher trophic levels typically have lower tolerance to high temperatures than lower trophic levels, trends towards increasing local or regional temperatures may affect the strength of predator/prey interactions and disrupt pest control. Furthermore, increasing temperatures may create climate corridors that could facilitate the invasion and establishment of invasive species originating from warmer areas. In this study we examined the effect of environmental conditions on the dynamics of an agro-ecosystem community located in southern Spain, using field data on predator/prey dynamics and climate gathered during four consecutive years. The study system was composed of an ever-green tree species (avocado), an exotic tetranychid mite, and two native species of phytoseiid mites found in association with this new pest. We also present a climatological analysis of the temperature trend in the area of study during the last 28 years, as evidence of temperature warming occurring in the area. We found that the range of temperatures with positive per capita growth rates was much wider in prey than in predators, and that relative humidity contributed to explain the growth rate variation in predators, but not in prey. Predator and prey differences in thermal performance curves could explain why natural enemies did not respond numerically to the pest when environmental conditions were harsh.

  12. Multi-Seasonal Nitrogen Recoveries from Crop Residue in Soil and Crop in a Temperate Agro-Ecosystem.

    Science.gov (United States)

    Hu, Guoqing; Liu, Xiao; He, Hongbo; Zhang, Wei; Xie, Hongtu; Wu, Yeye; Cui, Jiehua; Sun, Ci; Zhang, Xudong

    2015-01-01

    In conservation tillage systems, at least 30% of the soil surface was covered by crop residues which generally contain significant amounts of nitrogen (N). However, little is known about the multi-seasonal recoveries of the N derived from these crop residues in soil-crop systems, notably in northeastern China. In a temperate agro-ecosystem, 15N-labeled maize residue was applied to field surfaces in the 1st year (2009). From the 2nd to 4th year (2010-2012), one treatment halted the application of maize residue, whereas the soil in the second treatment was re-applied with unlabeled maize residue. Crop and soil samples were collected after each harvest, and their 15N enrichments were determined on an isotope ratio mass spectrometer to trace the allocation of N derived from the initially applied maize residue in the soil-crop systems. On average, 8.4% of the maize residue N was recovered in the soil-crop in the 1st year, and the vast majority (61.9%-91.9%) was recovered during subsequent years. Throughout the experiment, the cumulative recovery of the residue N in the crop increased gradually (18.2%-20.9%), but most of the residue N was retained in the soil, notably in the 0-10 cm soil layer. Compared to the single application, the sequential residue application significantly increased the recovery of the residue N in the soil profile (73.8% vs. 40.9%) and remarkably decreased the total and the initially applied residue derived mineral N along the soil profile. Our results suggested that the residue N was actively involved in N cycling, and its release and recovery in crop and soil profile were controlled by the decomposition process. Sequential residue application significantly enhanced the retention and stabilization of the initially applied residue N in the soil and retarded its translocation along the soil profile.

  13. Greenhouse gas emissions from agro-ecosystems and their contribution to environmental change in the Indus Basin of Pakistan

    Science.gov (United States)

    Iqbal, M. Mohsin; Goheer, M. Arif

    2008-11-01

    There is growing concern that increasing concentrations of greenhouse gases in the atmosphere have been responsible for global warming through their effect on radiation balance and temperature. The magnitude of emissions and the relative importance of different sources vary widely, regionally and locally. The Indus Basin of Pakistan is the food basket of the country and agricultural activities are vulnerable to the effects of global warming due to accelerated emissions of GHGs. Many developments have taken place in the agricultural sector of Pakistan in recent decades in the background of the changing role of the government and the encouragement of the private sector for investment in new ventures. These interventions have considerable GHG emission potential. Unfortunately, no published information is currently available on GHG concentrations in the Indus Basin to assess their magnitude and emission trends. The present study is an attempt to estimate GHG (CO2, CH4 and N2O) emissions arising from different agro-ecosystems of Indus Basin. The GHGs were estimated mostly using the IPCC Guidelines and data from the published literature. The results showed that CH4 emissions were the highest (4.126 Tg yr-1) followed by N2O (0.265 Tg yr-1) and CO2 (52.6 Tg yr-1). The sources of CH4 are enteric fermentation, rice cultivation and cultivation of other crops. N2O is formed by microbial denitrification of NO3 produced from applied fertilizer-N on cropped soils or by mineralization of native organic matter on fallow soils. CO2 is formed by the burning of plant residue and by soil respiration due to the decomposition of soil organic matter.

  14. Multi-scale geospatial agroecosystem modeling: a case study on the influence of soil data resolution on carbon budget estimates

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xuesong; Sahajpal, Ritvik; Manowitz, D.; Zhao, Kaiguang; LeDuc, Stephen D.; Xu, Min; Xiong, Wei; Zhang, Aiping; Izaurralde, Roberto C.; Thomson, Allison M.; West, Tristram O.; Post, W. M.

    2014-05-01

    The development of effective measures to stabilize atmospheric CO2 concentration and mitigate negative impacts of climate change requires accurate quantification of the spatial variation and magnitude of the terrestrial carbon (C) flux. However, the spatial pattern and strength of terrestrial C sinks and sources remain uncertain. In this study, we designed a spatially-explicit agroecosystem modeling system by integrating the Environmental Policy Integrated Climate (EPIC) model with multiple sources of geospatial and surveyed datasets (including crop type map, elevation, climate forcing, fertilizer application, tillage type and distribution, and crop planting and harvesting date), and applied it to examine the sensitivity of cropland C flux simulations to two widely used soil databases (i.e. State Soil Geographic-STATSGO of a scale of 1:250,000 and Soil Survey Geographic-SSURGO of a scale of 1:24,000) in Iowa, USA. To efficiently execute numerous EPIC runs resulting from the use of high resolution spatial data (56m), we developed a parallelized version of EPIC. Both STATSGO and SSURGO led to similar simulations of crop yields and Net Ecosystem Production (NEP) estimates at the State level. However, substantial differences were observed at the county and sub-county (grid) levels. In general, the fine resolution SSURGO data outperformed the coarse resolution STATSGO data for county-scale crop-yield simulation, and within STATSGO, the area-weighted approach provided more accurate results. Further analysis showed that spatial distribution and magnitude of simulated NEP were more sensitive to the resolution difference between SSURGO and STATSGO at the county or grid scale. For over 60% of the cropland areas in Iowa, the deviations between STATSGO- and SSURGO-derived NEP were larger than 1MgCha(-1)yr(-1), or about half of the average cropland NEP, highlighting the significant uncertainty in spatial distribution and magnitude of simulated C fluxes resulting from

  15. The Role of Soil Biological Function in Regulating Agroecosystem Services and Sustainability in the Quesungual Agroforestry System

    Science.gov (United States)

    Fonte, S.; Pauli, N.; Rousseau, L.; SIX, J. W. U. A.; Barrios, E.

    2014-12-01

    The Quesungual agroforestry system from western Honduras has been increasingly promoted as a promising alternative to traditional slash-and-burn agriculture in tropical dry forest regions of the Americas. Improved residue management and the lack of burning in this system can greatly impact soil biological functioning and a number of key soil-based ecosystem services, yet our understanding of these processes has not been thoroughly integrated to understand system functionality as a whole that can guide improved management. To address this gap, we present a synthesis of various field studies conducted in Central America aimed at: 1) quantifying the influence of the Quesungual agroforestry practices on soil macrofauna abundance and diversity, and 2) understanding how these organisms influence key soil-based ecosystem services that ultimately drive the success of this system. A first set of studies examined the impact of agroecosystem management on soil macrofauna populations, soil fertility and key soil processes. Results suggest that residue inputs (derived from tree biomass pruning), a lack of burning, and high tree densities, lead to conditions that support abundant, diverse soil macrofauna communities under agroforestry, with soil organic carbon content comparable to adjacent forest. Additionally, there is great potential in working with farmers to develop refined soil quality indicators for improved land management. A second line of research explored interactions between residue management and earthworms in the regulation of soil-based ecosystem services. Earthworms are the most prominent ecosystem engineers in these soils. We found that earthworms are key drivers of soil structure maintenance and the stabilization of soil organic matter within soil aggregates, and also had notable impacts on soil nutrient dynamics. However, the impact of earthworms appears to depend on residue management practices, thus indicating the need for an integrated approach for

  16. Earth Observation Based Assessment of the Water Production and Water Consumption of Nile Basin Agro-Ecosystems

    Directory of Open Access Journals (Sweden)

    Wim G.M. Bastiaanssen

    2014-10-01

    Full Text Available The increasing competition for water resources requires a better understanding of flows, fluxes, stocks, and the services and benefits related to water consumption. This paper explains how public domain Earth Observation data based on Moderate Resolution Imaging Spectroradiometer (MODIS, Second Generation Meteosat (MSG, Tropical Rainfall Measurement Mission (TRMM and various altimeter measurements can be used to estimate net water production (rainfall (P > evapotranspiration (ET and net water consumption (ET > P of Nile Basin agro-ecosystems. Rainfall data from TRMM and the Famine Early Warning System Network (FEWS-NET RainFall Estimates (RFE products were used in conjunction with actual evapotranspiration from the Operational Simplified Surface Energy Balance (SSEBop and ETLook models. Water flows laterally between net water production and net water consumption areas as a result of runoff and withdrawals. This lateral flow between the 15 sub-basins of the Nile was estimated, and partitioned into stream flow and non-stream flow using the discharge data. A series of essential water metrics necessary for successful integrated water management are explained and computed. Net water withdrawal estimates (natural and humanly instigated were assumed to be the difference between net rainfall (Pnet and actual evapotranspiration (ET and some first estimates of withdrawals—without flow meters—are provided. Groundwater-dependent ecosystems withdraw large volumes of groundwater, which exceed water withdrawals for the irrigation sector. There is a strong need for the development of more open-access Earth Observation databases, especially for information related to actual ET. The fluxes, flows and storage changes presented form the basis for a global framework to describe monthly and annual water accounts in ungauged river basins.

  17. Effects of CO{sub 2} gas as leaks from geological storage sites on agro-ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Ravi H.; Colls, Jeremy J. [Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, NG7 2RD, Nottingham (United Kingdom); Steven, Michael D. [School of Geography, University of Nottingham, NG7 2RD, Nottingham (United Kingdom)

    2010-12-15

    Carbon capture and storage in geological formations has potential risks in the long-term safety because of the possibility of CO{sub 2} leakage. Effects of leaking gas, therefore, on vegetation, soil, and soil-inhabiting organisms are critical to understand. An artificial soil gassing and response detection field facility developed at the University of Nottingham was used to inject CO{sub 2} gas at a controlled flow rate (1 l min{sup -1}) into soil to simulate build-up of soil CO{sub 2} concentrations and surface fluxes from two land use types: pasture grassland, and fallow followed by winter bean. Mean soil CO{sub 2} concentrations was significantly higher in gassed pasture plots than in gassed fallow plots. Germination of winter bean sown in gassed fallow plots was severely hindered and the final crop stand was reduced to half. Pasture grass showed stress symptoms and above-ground biomass was significantly reduced compared to control plot. A negative correlation (r = -0.95) between soil CO{sub 2} and O{sub 2} concentrations indicated that injected CO{sub 2} displaced O{sub 2} from soil. Gassing CO{sub 2} reduced soil pH both in grass and fallow plots (p = 0.012). The number of earthworm castings was twice as much in gassed plots than in control plots. This study showed adverse effects of CO{sub 2} gas on agro-ecosystem in case of leakage from storage sites to surface. (author)

  18. Innovations and Lessons Learned Developing the USDA Long-Term Agroecosystem Research Network Common Observatory Data Repository

    Science.gov (United States)

    Campbell, J. D.; Heilman, P.; Goodrich, D. C.; Sadler, J.

    2015-12-01

    The objective for the USDA Long-Term Agroecosystem Research (LTAR) network Common Observatory Repository (CORe) is to provide data management services including archive, discovery, and access for consistently observed data across all 18 nodes. LTAR members have an average of 56 years of diverse historic data. Each LTAR has designated a representative 'permanent' site as the location's common meteorological observatory. CORe implementation is phased, starting with meteorology, then adding hydrology, eddy flux, soil, and biology data. A design goal was to adopt existing best practices while minimizing the additional data management duties for the researchers. LTAR is providing support for data management specialists at the locations and the National Agricultural Library is providing central data management services. Maintaining continuity with historical observations is essential, so observations from both the legacy and new common methods are included in CORe. International standards are used to store robust descriptive metadata (ISO 19115) for the observation station and surrounding locale (WMO), sensors (Sensor ML), and activity (e.g., re-calibration, locale changes) to provide sufficient detail for novel data re-use for the next 50 years. To facilitate data submission a simple text format was designed. Datasets in CORe will receive DOIs to encourage citations giving fair credit for data providers. Data and metadata access are designed to support multiple formats and naming conventions. An automated QC process is being developed to enhance comparability among LTAR locations and to generate QC process metadata. Data provenance is maintained with a permanent record of changes including those by local scientists reviewing the automated QC results. Lessons learned so far include increase in site acceptance of CORe with the decision to store data from both legacy and new common methods. A larger than anticipated variety of currently used methods with potentially

  19. Effectivity Of Agroedutourism To Strengthen Healthy Agro-Ecosystem Awareness Of Students In Some Elementary Schools In Malang Raya, East Java

    Directory of Open Access Journals (Sweden)

    Hanin Niswatul Fauziah

    2013-07-01

    Full Text Available This research aimed to study the effectivity of agroedutourism to strengthen students’ environmental awareness, especially concerning on importance of rice organic farming system. Eighty three students were invited joining the program. They were the 5th grade of three elementary schools (SDN Ketawanggede 2, SDI Surya Buana and SDN Sumberngepoh 02. It was provided three agroedutourism programs, i.e. two outdoors programs (Farmers’ friends and enemies, Plants for biopesticide and natural attractant, as well as the indoor session called Healthy agroecosystem. Including the programs were joining ecoeco-games and tasting some food (steamed rice-bran brownies, organic red rice milk and zalacca fruits. Effectivity of the programs was evaluated using questionnaire. Data were analyzed by SPSS program using Wilcoxon test (α=0,05. Results showed overall that the agroedutourism increased significantly students cognitive, affective and even their appreciation to agricultural environment. Students of SDN Sumberngepoh 02 showed a highest agro-environmental awareness. While, the highest cognitive improvement was gained by students of SDI Surya Buana (76%, followed by SDN Ketawanggede 2 (62% and SDN Sumberngepoh 02 (47%. The most interesting program was an outdoor namely Farmers’ friends and enemies, while they preferred a steamed rice-bran brownies than the other one. They were exciting joining some eco-games especially predator and prey as well as guest animal name and its role. It seemed that the outdoor programs were more appreciated rather than the indoor one. Keywords: Agroedutourism, awareness, effectivity, healthy agro-ecosystem

  20. Changes in cropland topsoil organic carbon with different fertilizations under long-term agro-ecosystem experiments across mainland China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Topsoil soil organic carbon(SOC) data were collected from long-term Chinese agro-ecosystem experiments presented in 76 reports with measurements over 1977 and 2006.The data set comprised 481 observations(135 rice paddies and 346 dry croplands) of SOC under different fertilization schemes at 70 experimental sites(28 rice paddies and 42 dry croplands).The data set covered 16 dominant soil types found in croplands across 23 provinces of mainland China.The fertilization schemes were grouped into six categories:N(inorganic nitrogen fertilizer only),NP(compound inorganic nitrogen and phosphorus fertilizers),NPK(compound inorganic nitrogen,phosphorus and potassium fertilizers),O(organic fertilizers only),OF(combined inorganic/organic fertilization) and Others(other unbalanced fertilizations such as P only,K only,P plus K and N plus K).Relative change in SOC content was analyzed,and rice paddies and dry croplands soils were compared.There was an overall temporal increase in topsoil SOC content,and relative annual change(RAC,g kg-1 yr-1) ranged -0.14-0.60(0.13 on average) for dry cropland soils and -0.12-0.70(0.19 on average) for rice paddies.SOC content increase was higher in rice paddies than in dry croplands.SOC increased across experimental sites,but was higher under organic fertilization and combined organic/inorganic fertilizations than chemical fertilizations.SOC increase was higher under balanced chemical fertilizations with compound N,P and K fertilizers than unbalanced fertilizations such as N only,N plus P,and N plus K.The effects of specific rational fertilizations on SOC increase persisted for 15 years in dry croplands and 20 years in rice paddies,although RAC values decreased generally as the experiment duration increased.Therefore,the extension of rational fertilization in China’s croplands may offer a technical option to enhance C sequestration potential and to sustain long-term crop productivity.

  1. Relevance of traditional integrated pest management (IPM) strategies for commercial corn producers in a transgenic agroecosystem: a bygone era?

    Science.gov (United States)

    Gray, Michael E

    2011-06-08

    The use of transgenic Bt maize hybrids continues to increase significantly across the Corn Belt of the United States. In 2009, 59% of all maize planted in Illinois was characterized as a "stacked" gene variety. This is a 40% increase since 2006. Stacked hybrids typically express one Cry protein for corn rootworm control and one Cry protein for control of several lepidopteran pests; they also feature herbicide tolerance (to either glyphosate or glufosinate). Slightly more than 50 years has passed since Vernon Stern and his University of California entomology colleagues published (1959) their seminal paper on the integrated control concept, laying the foundation for modern pest management (IPM) programs. To assess the relevance of traditional IPM concepts within a transgenic agroecosystem, commercial maize producers were surveyed at a series of meetings in 2009 and 2010 regarding their perceptions on their use of Bt hybrids and resistance management. Special attention was devoted to two insect pests of corn, the European corn borer and the western corn rootworm. A high percentage of producers who participated in these meetings planted Bt hybrids in 2008 and 2009, 97 and 96.7%, respectively. Refuge compliance in 2008 and 2009, as mandated by the U.S. Environmental Protection Agency (EPA), was 82 and 75.7%, respectively, for those producers surveyed. A large majority of producers (79 and 73.3% in 2009 and 2010, respectively) revealed that they would, or had, used a Bt hybrid for corn rootworm (Diabrotica virgifera virgifera LeConte) or European corn borer (Ostrinia nubilalis Hübner) control even when anticipated densities were low. Currently, the EPA is evaluating the long-term use of seed blends (Bt and non-Bt) as a resistance management strategy. In 2010, a large percentage of producers, 80.4%, indicated they would be willing to use this approach. The current lack of integration of management tactics for insect pests of maize in the U.S. Corn Belt, due primarily to

  2. Floristic diversity in agro-ecosystem livestock bovine of the Canton “El Carmen” in Manabi’s province, Ecuador

    Directory of Open Access Journals (Sweden)

    Justo A. Rojas Rojas

    2016-01-01

    Full Text Available In the second half of 2013 the species that are part of the diversity of flora in agroecosystems cattle ranching bovine in Canton El Carmen, Manabí, Ecuador were determined. A total of 13 botanical species of which Sida acuta Burm. had the highest records with 29.7 % of dominance and a frequency of 51.0 %, followed by the species Senna obtusifolia (L. H. S. Irwin & Barneby, Desmodium tortuosum (Sw. DC, Pavonia sidifolia Kunth and Stachytarpheta cayennensis (Rich. Vahl. These five species were found to be the most dominant and frequent with respect to all the species found. The Jaccard coefficient showed 53,8 % similarity regarding diversity of plant species.

  3. Agro-ecosystem and socio-economic role of homegarden agroforestry in Jabithenan District, North-Western Ethiopia: implication for climate change adaptation.

    Science.gov (United States)

    Linger, Ewuketu

    2014-01-01

    Homegarden agroforestry is believed to be more diverse and provide multiple services for household than other monocropping system and this is due to the combination of crops, trees and livestock. The aim of this study was to assess socio-economic and agro-ecological role of homegardens in Jabithenan district, North-western Ethiopia. Two sites purposively and two villages randomly from each site were selected. Totally 96 households; in which 48 from homegarden agroforestry user and 48 from non-tree based garden user were selected for this study. Socio-economic data and potential economic and agro-ecosystem role of homegarden agroforestry over non-tree based garden were collected by using semi-structured and structured questionnaires to the households. Homegarden agroforestry significantly (P homegarden agroforestry practice provides good socio-economical and agro-ecological service for farmers which have a higher implication for climate change adaptation than non-tree based garden.

  4. Linking spatial patterns of soil redistribution traced with 137Cs and soil nutrients in a Mediterranean mountain agroecosystem (NE Spain)

    Science.gov (United States)

    Quijano, Laura; Gaspar, Leticia; Navas, Ana

    2016-04-01

    Mediterranean mountain agroecosystems are prone to soil loss mainly due to the accelerated erosion as a consequence of human induced changes from agriculture and grazing practices over the last centuries and the climatic conditions (i.e. irregular and scarce precipitations and drought periods). Soil erosion leads to soil degradation inducing the loss of soil functions. The progressive decline of soil functions thereof soil quality is associated to a decrease of soil productivity and can threat the sustainability of cultivated soils. The use of fallout 137Cs as a soil movement tracer provides useful data to identify areas where loss and gain of 137Cs occurs and that of soil. This study aims to address soil movement and soil nutrient dynamics closely related to the status of soil degradation. A rain-fed cereal field (1.6 ha) representative of Mediterranean mountain agricultural landscapes (42°25'41''N 1°13'8''W) was selected to examine the effects of soil redistribution processes on the spatial variability of soil organic carbon (SOC) and nitrogen (SON) and their relationships with soil properties and topographic characteristics. From the hydrological point of view, the field is isolated due to the effect of landscape features and man-made structures. Climate is continental Mediterranean with an average annual rainfall of 500 mm and soils are Calcisols. The reference inventories of 137Cs and soil nutrients were established from 21 soil samples collected in nearby undisturbed areas under typical Mediterranean vegetation cover. A total of 156 bulk soil samples (30-50 cm depth) and 156 topsoil samples (5 cm) were collected on a 10 m grid. 137Cs and soil nutrients loss and gain areas were identified by comparing the reference inventories with the values of inventories at the sampling points. A new approach to characterize and measure active (ACF) and stable (SCF) carbon fraction contents by using a dry combustion method based on the oxidation temperature of carbon

  5. Seasonal and Annual Variations of CO2 Fluxes in Rain-Fed Winter Wheat Agro-Ecosystem of Loess Plateau, China

    Institute of Scientific and Technical Information of China (English)

    WANG Wen; LIAO Yun-cheng; GUO Qiang

    2013-01-01

    To accurately evaluate the carbon sequestration potential and better elucidate the relationship between the carbon cycle and regional climate change, using eddy covariance system, we conducted a long-term measurement of CO2 fluxes in the rain-fed winter wheat field of the Chinese Loess Plateau. The results showed that the annual net ecosystem CO2 exchange (NEE) was (-71.6±5.7) and (-65.3±5.3) gCm-2y-1 for 2008-2009 and 2009-2010 crop years, respectively, suggesting that the agro-ecosystem was a carbon sink (117.4-126. 2gCm-2yr-1). However, after considering the harvested grain, the agro-ecosystem turned into a moderate carbon source. The variations in NEE and ecosystem respiration (Reco) were sensitive to changes in soil water content (SWC). When SWC ranged form 0.15 to 0.21 m3 m-3, we found a highly significant relationship between NEE and photosynthetically active radiation (PAR), and a highly significant relationship between Reco and soil temperature (Ts). However, the highly significant relationships were not observed when SWC was outside the range of 0.15-0.21 m3 m-3. Further, in spring, the Reco instantly responded to a rapid increase in SWC after effective rainfall events, which could induce 2 to 4-fold increase in daily Reco, whereas the Reco was also inhibited by heavy summer rainfall when soils were saturated. Accumulated Reco in summer fallow period decreased carbon fixed in growing season by 16-25%, indicating that the period imposed negative impacts on annual carbon sequestration.

  6. Looking beyond fertilizer: Assessing the contribution of nitrogen from hydrologic inputs and organic matter to plant growth in the cranberry agroecosystem

    Science.gov (United States)

    Stackpoole, S.M.; Kosola, K.R.; Workmaster, B.A.A.; Guldan, N.M.; Browne, B.A.; Jackson, R. D.

    2011-01-01

    Even though nitrogen (N) is a key nutrient for successful cranberry production, N cycling in cranberry agroecosystems is not completely understood. Prior research has focused mainly on timing and uptake of ammonium fertilizer, but the objective of our study was to evaluate the potential for additional N contributions from hydrologic inputs (flooding, irrigation, groundwater, and precipitation) and organic matter (OM). Plant biomass, soil, surface and groundwater samples were collected from five cranberry beds (cranberry production fields) on four different farms, representing both upland and lowland systems. Estimated average annual plant uptake (63.3 ?? 22.5 kg N ha-1 year-1) exceeded total average annual fertilizer inputs (39.5 ?? 11.6 kg N ha-1 year-1). Irrigation, precipitation, and floodwater N summed to an average 23 ?? 0.7 kg N ha-1 year-1, which was about 60% of fertilizer N. Leaf and stem litterfall added 5.2 ?? 1.2 and 24.1 ?? 3.0 kg N ha-1 year-1 respectively. The estimated net N mineralization rate from the buried bag technique was 5 ?? 0.2 kg N ha-1 year-1, which was nearly 15% of fertilizer N. Dissolved organic nitrogen represented a significant portion of the total N pool in both surface water and soil samples. Mixed-ion exchange resin core incubations indicated that 80% of total inorganic N from fertilizer, irrigation, precipitation, and mineralization was nitrate, and approximately 70% of recovered inorganic N from groundwater was nitrate. There was a weak but significant negative relationship between extractable soil ammonium concentrations and ericoid mycorrhizal colonization (ERM) rates (r = -0.22, P fertilizer N in order to maximize the benefits of ERM fungi in actively mediating N cycling in cranberry agroecosystems. ?? 2011 Springer Science+Business Media B.V.

  7. Emergy Analysis of Agroecosystem in Huang-huai-hai Region%黄淮海地区农业生态经济系统能值分析

    Institute of Scientific and Technical Information of China (English)

    曹志宏; 郝晋珉; 梁流涛

    2009-01-01

    为了更好地评价黄淮海地区农业生态经济系统的运行特征和可持续发展状况,本文利用能值分析理论通过构建评估指标体系.对黄淮海地区农业生态系统的能值投入产出状况、环境承载情况和生态系统运行效果进行了定量分析.结果表明黄淮海地区农业生态系统能值产出率相对较高,整体运行状况较好,具有较强市场竞争力,环境承受能力较强和可持续发展能力较强,但仍处于石油农业发展阶段,其化肥、农药和地膜等工业辅助能值大幅度增加,其发展可持续性有一定下降趋势,造成对生态环境的较大压力应引起关注.为促进黄淮海地区农业的可持续发展,应调整其能值投入和产出结构,加大农业科技的研究和推广力度,适"-3降低以化肥为代表的工业辅助能投入,改变化工农业生产模式,走农业可持续发展的道路.%In this paper,the emergy input and output,environmental loading and running effect of agroecosystem in Huang-huai-hai region were quantitatively analyzed to better evaluate its operating characteristics and the sustainable development ofagrienlture based on the theory of emergy analysis by structuring index system for agroecosystem cmergy estimation. The results show that the agroecosystem in Huang-huai-hai region has higher efficiency of emergy output, better effect of running, stronger manet competition, more powerful environmental carrying capacity and sustainable development capacity, but it still at the stage of petroleum agriculture, chemical fertilizer, pesticide and plastic film etc. Unrenewable industrial emergy raising by big percentages leads to its sustainability of decreasing trend to a certain degree, and causes greater pressure to the ecological environment which we should pay more attention to. To promote the sustainable development of agriculture in Huang-huai-hai region, we should gradually adjust the invesunent proportion of input and

  8. Reduced tillage and cover crops as a strategy for mitigating atmospheric CO2 increase through soil organic carbon sequestration in dry Mediterranean agroecosystems.

    Science.gov (United States)

    Almagro, María; Garcia-Franco, Noelia; de Vente, Joris; Boix-Fayos, Carolina; Díaz-Pereira, Elvira; Martínez-Mena, María

    2016-04-01

    The implementation of sustainable land management (SLM) practices in semiarid Mediterranean agroecosystems can be beneficial to maintain or enhance levels of soil organic carbon and mitigate current atmospheric CO2 increase. In this study, we assess the effects of different tillage treatments (conventional tillage (CT), reduced tillage (RT), reduced tillage combined with green manure (RTG), and no tillage (NT)) on soil CO2 efflux, aggregation and organic carbon stabilization in two semiarid organic rainfed almond (Prunus dulcis Mill., var. Ferragnes) orchards located in SE Spain Soil CO2 efflux, temperature and moisture were measured monthly between May 2012 and December 2014 (site 1), and between February 2013 and December 2014 (site 2). In site 1, soil CO2 efflux rates were also measured immediately following winter and spring tillage operations. Aboveground biomass inputs were estimated at the end of the growing season in each tillage treatment. Soil samples (0-15 cm) were collected in the rows between the trees (n=4) in October 2012. Four aggregate size classes were distinguished by sieving (large and small macroaggregates, free microaggregates, and free silt plus clay fraction), and the microaggregates occluded within macroaggregates (SMm) were isolated. Soil CO2efflux rates in all tillage treatments varied significantly during the year, following changes during the autumn, winter and early spring, or changes in soil moisture during late spring and summer. Repeated measures analyses of variance revealed that there were no significant differences in soil CO2 efflux between tillage treatments throughout the study period at both sites. Average annual values of C lost by soil respiration were slightly but not significantly higher under RT and RTG treatments (492 g C-CO2 m-2 yr-1) than under NT treatment (405 g C-CO2 m-2 yr-1) in site 1, while slightly but not significantly lower values were observed under RT and RTG treatments (468 and 439 g C-CO2 m-2 yr-1

  9. Adopt to sustain: The effect of biophysical and socioeconomic context on the ability of two contrasting U.S. agroecosystems to respond to changes

    Science.gov (United States)

    Papanicolaou, T.

    2015-12-01

    Increased demand for food, feed, fuel and fiber in U.S. agroecosystems has deleterious effects on the environment. Gauging the responses of these agroecosystems in the presence of extreme events and new market demands requires a fresh approach. This approach requires better comprehension of the interactions and feedback processes that either sustain or deplete both natural (e.g., soil productivity) and human (e.g., net income) capital. Because soil quality defines land productivity and long-term prosperity, we focus on the cascading effects that soil quality has on other ecosystem properties, profit, farmer decision making in mitigating soil degradation, and development of environmental policies. We argue that land use decision-making must not only be strictly based on socioeconomic and environmental criteria, but should also consider farmer/ farm characteristics, personal beliefs, and the support network that is needed for promoting and implementing conservation practices. Current approaches for adopting conservation do not fit into this paradigm. We develop an Agent Based Model Framework that incorporates novel aspects of ecological, socioeconomic and behavioral modeling to facilitate interactions of the farmer and its land through a multi-objective, maximization utility function. This function is continuously informed and updated by the improved modeling framework. This study is developing measures of sustainability for lags, hysteresis, tipping points, and adaptive capacity. We examine the complex relationship between farmer decision-making and the landscape in two contrasting systems in Iowa and Tennessee with unique distributions of characteristics in terms of climate, soil properties, and landscape patterns that regulate not only the type of farming practiced, but also the degree of soil erosion in each system. Central to this investigation is identifying and quantifying trade-offs among non-pecuniary and pecuniary objectives given alternative scenarios

  10. Efectos de diferentes agroecosistemas en la dinámica de nitrógeno, fósforo y potasio en un cultivo de tomate Effects of different agro-ecosystems in the dynamic of nitrogen, phosphorous, and potassium in the tomato crop

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Bouzo

    Full Text Available El objetivo de este trabajo fue evaluar la dinámica del nitrógeno, fósforo y potasio en cultivos de tomate y suelos en diferentes agroecosistemas. El trabajo consistió en estudiar el efecto de tres agroecosistemas: agrícola (T1, natural (T2 y hortícola (T3. Estos agroecosistemas se caracterizaron por la secuencia de los cultivos de maíz y trigo durante 8 años (T1, vegetación natural de gramíneas (T2 y rotaciones de cultivos hortícolas durante 20 años (T3. El estudio fue realizado en Santa Fe, Argentina (31° 15' S, 60° 50' W entre 2009 y 2010, habiéndose utilizado un cultivar de tomate híbrido redondo de crecimiento indeterminado. La concentración de N-NO3- en los suelos tuvo un valor alto (The objective ofthis research was to evaluate the dynamics of nitrogen, phosphorous, and potassium in tomato crops and in different soils of agro-ecosystems. The research consisted of studying the effect of three agro-ecosystems: 1 agricultural (T1, natural (T2 and horticultural (T3. These agro-ecosystems are characterized by the sequence of the maize and wheat crops during 8 years (T1, natural vegetation of grasses (T2, and rotation of horticultural crops during 20 years (T3. The study was done in Santa Fe, Argentina (31° 15' S, 60° 50' W between 2009 and 2010, having used a hybrid tomato crop, round with indeterminate growth. The concentration of N-NO3- in the soils had a high value (< 65 ppm at the beginning of the crop in the three agro-ecosystems. The concentration of P was also very high (< 250 ppm in the horticultural agro-ecosystem (T3 and less than the rest, with approximately 50 ppm for T1 and 150 ppm for T2. The same occurred in this agro-ecosystem with K. The natural agro-ecosystem (T2 was the one that had the lowest concentration of P in the soil. The concentrations of N, P, and K resulted with highly significant differences (p≤ 0.01 in the concentrations of the stalks of the plants coming from the three agro-ecosystems

  11. Atmospheric deposition, resuspension and root uptake of plutonium in corn and other grain-producing agroecosystems near a nuclear fuel facility

    Energy Technology Data Exchange (ETDEWEB)

    Pinder, J.E. III; McLeod, K.W.; Adriano, D.C. (Savannah River Ecology Lab., Aiken, SC (United States)); Corey, J.C.; Boni, A.L. (Savannah River Lab., Aiken, SC (United States))

    1989-01-01

    Plutonium released to the environment may contribute to dose to humans through inhalation or ingestion of contaminated foodstuffs. Plutonium contamination of agricultural plants may result from interception and retention of atmospheric deposition, resuspension of Pu-bearing soil particles to plant surfaces, and root uptake and translocation to grain. Plutonium on vegetation surfaces may be transferred to grain surfaces during mechanical harvesting. Data obtained from corn grown near the US Department of Energy's H-Area nuclear fuel chemical separations facility on the Savannah River Site was used to estimated parameters of a simple model of Pu transport in agroecosystems. The parameter estimates for corn were compared to those previously obtained for wheat and soybeans. Despite some differences in parameter estimates among crops, the relative importances of atmospheric deposition, resuspension and root uptake were similar among crops. For even small deposition rates, the relative importances of processes for Pu contamination of corn grain should be: transfer of atmospheric deposition from vegetation surfaces to grain surfaces during combining > resuspension of soil to grain surfaces > root uptake. Approximately 3.9 {times} 10{sup {minus}5} of a year's atmospheric deposition is transferred to grain. Approximately 6.2 {times} 10{sup {minus}9} of the Pu inventory in the soil is resuspended to corn grain, and a further 7.3 {times} 10{sup {minus}10} of the soil inventory is absorbed by roots and translocated to grains.

  12. Atmospheric deposition, resuspension and root uptake of plutonium in corn and other grain-producing agroecosystems near a nuclear fuel facility

    Energy Technology Data Exchange (ETDEWEB)

    Pinder, J.E. III; McLeod, K.W.; Adriano, D.C. [Savannah River Ecology Lab., Aiken, SC (United States); Corey, J.C.; Boni, A.L. [Savannah River Lab., Aiken, SC (United States)

    1989-12-31

    Plutonium released to the environment may contribute to dose to humans through inhalation or ingestion of contaminated foodstuffs. Plutonium contamination of agricultural plants may result from interception and retention of atmospheric deposition, resuspension of Pu-bearing soil particles to plant surfaces, and root uptake and translocation to grain. Plutonium on vegetation surfaces may be transferred to grain surfaces during mechanical harvesting. Data obtained from corn grown near the US Department of Energy`s H-Area nuclear fuel chemical separations facility on the Savannah River Site was used to estimated parameters of a simple model of Pu transport in agroecosystems. The parameter estimates for corn were compared to those previously obtained for wheat and soybeans. Despite some differences in parameter estimates among crops, the relative importances of atmospheric deposition, resuspension and root uptake were similar among crops. For even small deposition rates, the relative importances of processes for Pu contamination of corn grain should be: transfer of atmospheric deposition from vegetation surfaces to grain surfaces during combining > resuspension of soil to grain surfaces > root uptake. Approximately 3.9 {times} 10{sup {minus}5} of a year`s atmospheric deposition is transferred to grain. Approximately 6.2 {times} 10{sup {minus}9} of the Pu inventory in the soil is resuspended to corn grain, and a further 7.3 {times} 10{sup {minus}10} of the soil inventory is absorbed by roots and translocated to grains.

  13. Evaluation of a regional air-quality model with bi-directional NH3 exchange coupled to an agro-ecosystem model

    Directory of Open Access Journals (Sweden)

    J. E. Pleim

    2012-08-01

    Full Text Available Atmospheric ammonia (NH3 is the primary atmospheric base and an important precursor for inorganic particulate matter and when deposited NH3 contributes to surface water eutrophication, soil acidification and decline in species biodiversity. Flux measurements indicate that the air-surface exchange of NH3 is bi-directional. However, the effects of bi-directional exchange, soil biogeochemistry and human activity are not parameterized in air quality models. The US Environmental Protection Agency (EPA's Community Multiscale Air-Quality (CMAQ model with bi-directional NH3 exchange has been coupled with the United States Department of Agriculture (USDA's Environmental Policy Integrated Climate (EPIC agro-ecosystem model's nitrogen geochemistry algorithms. CMAQ with bi-directional NH3 exchange coupled to EPIC connects agricultural cropping management practices to emissions and atmospheric concentrations of reduced nitrogen and models the biogeochemical feedback on NH3 air-surface exchange. This coupled modeling system reduced the biases and error in NHx (NH3 + NH4+ wet deposition and in ambient aerosol concentrations in an annual 2002 Continental US (CONUS domain simulation when compared to a 2002 annual simulation of CMAQ without bi-directional exchange. Fertilizer emissions estimated in CMAQ 5.0 with bi-directional exchange exhibits markedly different seasonal dynamics than the US EPA's National Emissions Inventory (NEI, with lower emissions in the spring and fall and higher emissions in July.

  14. Changes in soil C-isotopic composition in an agroecosystem under Free Air Carbon dioxide Enrichment (FACE) treatment during a crop rotation period.

    Science.gov (United States)

    Giesemann, Anette

    2005-01-01

    FACE (Free Air Carbon dioxide Enrichment) has been used since 1999 to evaluate the effects of future atmospheric CO(2) concentrations on an arable crop agroecosystem. The experiment conducted at the Institute of Agroecology at the Federal Research Centre in Braunschweig consists of a typical local crop rotation of winter barley, a cover crop, sugar beet and winter wheat. The atmospheric CO2 concentration of ambient air is about 375 ppm with a delta13C value of -7 to -9 per thousand, and 550 ppm (delta13C value = -20.2 per thousand) during daylight hours in the rings fumigated with additional CO2. Thus, the surplus C can be traced in the agricultural system. Over the course of the first experimental period (3-year crop rotation period), the C-isotopic composition and the C concentration in soil were monitored monthly. Plant samples were analysed according to the relevant developmental stages of the crop under cultivation. A 13C depletion was observed in plant parts, as well as in soil samples from the FACE rings under CO2 enrichment, indicating that labelled C has reached both respective ecosystem compartments. Albeit farming management practice (especially ploughing) leads to a mixing of 'old' and 'new' C compounds throughout all soil horizons down to the end of the ploughing layer and resulted in a heterogeneous distribution of newly formed C compounds in the soil, isotope analysis of soil C reflected where the surplus C went.

  15. Changes in species diversity of arboreal spiders in Mexican coffee agroecosystems: untangling the web of local and landscape influences driving diversity.

    Science.gov (United States)

    Hajian-Forooshani, Zachary; Gonthier, David J; Marín, Linda; Iverson, Aaron L; Perfecto, Ivette

    2014-01-01

    Agricultural intensification is implicated as a major driver of global biodiversity loss. Local management and landscape scale factors both influence biodiversity in agricultural systems, but there are relatively few studies to date looking at how local and landscape scales influence biodiversity in tropical agroecosystems. Understanding what drives the diversity of groups of organisms such as spiders is important from a pragmatic point of view because of the important biocontrol services they offer to agriculture. Spiders in coffee are somewhat enigmatic because of their positive or lack of response to agricultural intensification. In this study, we provide the first analysis, to our knowledge, of the arboreal spiders in the shade trees of coffee plantations. In the Soconusco region of Chiapas, Mexico we sampled across 38 sites on 9 coffee plantations. Tree and canopy connectedness were found to positively influence overall arboreal spider richness and abundance. We found that different functional groups of spiders are responding to different local and landscape factors, but overall elevation was most important variable influencing arboreal spider diversity. Our study has practical management applications that suggest having shade grown coffee offers more suitable habitat for arboreal spiders due to a variety of the characteristics of the shade trees. Our results which show consistently more diverse arboreal spider communities in lower elevations are important in light of looming global climate change. As the range of suitable elevations for coffee cultivation shrinks promoting arboreal spider diversity will be important in sustaining the viability of coffee.

  16. Changes in species diversity of arboreal spiders in Mexican coffee agroecosystems: untangling the web of local and landscape influences driving diversity

    Directory of Open Access Journals (Sweden)

    Zachary Hajian-Forooshani

    2014-11-01

    Full Text Available Agricultural intensification is implicated as a major driver of global biodiversity loss. Local management and landscape scale factors both influence biodiversity in agricultural systems, but there are relatively few studies to date looking at how local and landscape scales influence biodiversity in tropical agroecosystems. Understanding what drives the diversity of groups of organisms such as spiders is important from a pragmatic point of view because of the important biocontrol services they offer to agriculture. Spiders in coffee are somewhat enigmatic because of their positive or lack of response to agricultural intensification. In this study, we provide the first analysis, to our knowledge, of the arboreal spiders in the shade trees of coffee plantations. In the Soconusco region of Chiapas, Mexico we sampled across 38 sites on 9 coffee plantations. Tree and canopy connectedness were found to positively influence overall arboreal spider richness and abundance. We found that different functional groups of spiders are responding to different local and landscape factors, but overall elevation was most important variable influencing arboreal spider diversity. Our study has practical management applications that suggest having shade grown coffee offers more suitable habitat for arboreal spiders due to a variety of the characteristics of the shade trees. Our results which show consistently more diverse arboreal spider communities in lower elevations are important in light of looming global climate change. As the range of suitable elevations for coffee cultivation shrinks promoting arboreal spider diversity will be important in sustaining the viability of coffee.

  17. Progress and perspectives in studies on agro-ecosystem carbon cycle model%农田生态系统碳循环模型研究进展和展望

    Institute of Scientific and Technical Information of China (English)

    刘昱; 陈敏鹏; 陈吉宁

    2015-01-01

    Agro-ecosystem, as the most active and controllable carbon pool in terrestrial ecosystem carbon cycle, can lead to substantial changes in the atmospheric CO2 concentration, thus affecting remarkably the global climate. The carbon cycle in agro-ecosystem is a complex process, which is influenced by factors such as climate, plants, soil properties and farm management. It is recognized that a model approach has an advantage in estimating spatiotemporal changes in carbon storage. Carbon cycle models are considered to be the most effective means to study carbon cycle. This paper emphasized on the carbon cycle process of agro-ecosystem, introduced the transference and the mechanism of carbon cycle between different carbon pools, identified characteristics of different models in association with carbon cycle of agro-ecosystem from 1960s, summarized and analyzed the application of international carbon models and others invented and developed in China in the agro-ecosystem. During these years, several models, such as RothC, CENTURY, DNDC, EPIC and APSIM have been widely used to estimate carbon changes at national or global scales. These models provide understanding of carbon flow through food webs and explore the role of carbon storage in the whole agro-ecosystem. They also allow analysis of environmental risks and provide a guide to know more about the relationship among carbon, nitrogen and water cycle. More recently, some new carbon models have been developed in China for simulating the carbon budget of agro-ecosystems. For example, the Agro-C can simulate crop net primary production via Crop-C sub model and changes in soil organic carbon via Soil-C sub model under various conditions of climate, soil, and agricultural practices, which makes it possible to extrapolate the model to a wider domain. Validation of the Soil-C sub model suggested that an inappropriate simplification of the carbon flow between various C pools may introduce errors into the estimates. Carbon loss

  18. Estimating NH3 emissions from agricultural fertilizer application in China using the bi-directional CMAQ model coupled to an agro-ecosystem model

    Science.gov (United States)

    Fu, X.; Wang, S. X.; Ran, L. M.; Pleim, J. E.; Cooter, E.; Bash, J. O.; Benson, V.; Hao, J. M.

    2015-06-01

    Atmospheric ammonia (NH3) plays an important role in atmospheric aerosol chemistry. China is one of the largest NH3 emitting countries with the majority of NH3 emissions coming from agricultural practices, such as fertilizer application and livestock production. The current NH3 emission estimates in China are mainly based on pre-defined emission factors that lack temporal or spatial details, which are needed to accurately predict NH3 emissions. This study provides the first online estimate of NH3 emissions from agricultural fertilizer application in China, using an agricultural fertilizer modeling system which couples a regional air quality model (the Community Multi-scale Air Quality model, or CMAQ) and an agro-ecosystem model (the Environmental Policy Integrated Climate model, or EPIC). This method improves the spatial and temporal resolution of NH3 emissions from this sector. We combined the cropland area data of 14 crops from 2710 counties with the Moderate Resolution Imaging Spectroradiometer (MODIS) land use data to determine the crop distribution. The fertilizer application rates and methods for different crops were collected at provincial or agricultural region levels. The EPIC outputs of daily fertilizer application and soil characteristics were input into the CMAQ model and the hourly NH3 emissions were calculated online with CMAQ running. The estimated agricultural fertilizer NH3 emissions in this study were approximately 3 Tg in 2011. The regions with the highest modeled emission rates are located in the North China Plain. Seasonally, peak ammonia emissions occur from April to July. Compared with previous researches, this study considers an increased number of influencing factors, such as meteorological fields, soil and fertilizer application, and provides improved NH3 emissions with higher spatial and temporal resolution.

  19. The Influence of Culture on Agroecosystem Structure: A Comparison of the Spatial Patterns of Homegardens of Different Ethnic Groups in Thailand and Vietnam.

    Directory of Open Access Journals (Sweden)

    Pijika Timsuksai

    Full Text Available Different ethnic groups have evolved distinctive cultural models which guide their interactions with the environment, including their agroecosystems. Although it is probable that variations in the structures of homegardens among separate ethnic groups reflect differences in the cultural models of the farmers, empirical support for this assumption is limited. In this paper the modal horizontal structural patterns of the homegardens of 8 ethnic groups in Northeast Thailand and Vietnam are described. Six of these groups (5 speaking Tai languages and 1 speaking Vietnamese live in close proximity to each other in separate villages in Northeast Thailand, and 2 of the groups (one Tai-speaking and one Vietnamese-speaking live in different parts of Vietnam. Detailed information on the horizontal structure of homegardens was collected from samples of households belonging to each group. Although each ethnic group has a somewhat distinctive modal structure, the groups cluster into 2 different types. The Tai speaking Cao Lan, Kalaeng, Lao, Nyaw, and Yoy make up Type I while both of the Vietnamese groups, along with the Tai speaking Phu Thai, belong to Type II. Type I gardens have predominantly organic shapes, indeterminate boundaries, polycentric planting patterns, and multi-species composition within planting areas. Type II homegardens have geometric shapes, sharp boundaries, lineal planting patterns, and mono-species composition of planting areas. That the homegardens of most of the Tai ethnic groups share a relatively similar horizontal structural pattern that is quite different from the pattern shared by both of the Vietnamese groups suggests that the spatial layout of homegardens is strongly influenced by their different cultural models.

  20. The Influence of Culture on Agroecosystem Structure: A Comparison of the Spatial Patterns of Homegardens of Different Ethnic Groups in Thailand and Vietnam.

    Science.gov (United States)

    Timsuksai, Pijika; Rambo, A Terry

    2016-01-01

    Different ethnic groups have evolved distinctive cultural models which guide their interactions with the environment, including their agroecosystems. Although it is probable that variations in the structures of homegardens among separate ethnic groups reflect differences in the cultural models of the farmers, empirical support for this assumption is limited. In this paper the modal horizontal structural patterns of the homegardens of 8 ethnic groups in Northeast Thailand and Vietnam are described. Six of these groups (5 speaking Tai languages and 1 speaking Vietnamese) live in close proximity to each other in separate villages in Northeast Thailand, and 2 of the groups (one Tai-speaking and one Vietnamese-speaking) live in different parts of Vietnam. Detailed information on the horizontal structure of homegardens was collected from samples of households belonging to each group. Although each ethnic group has a somewhat distinctive modal structure, the groups cluster into 2 different types. The Tai speaking Cao Lan, Kalaeng, Lao, Nyaw, and Yoy make up Type I while both of the Vietnamese groups, along with the Tai speaking Phu Thai, belong to Type II. Type I gardens have predominantly organic shapes, indeterminate boundaries, polycentric planting patterns, and multi-species composition within planting areas. Type II homegardens have geometric shapes, sharp boundaries, lineal planting patterns, and mono-species composition of planting areas. That the homegardens of most of the Tai ethnic groups share a relatively similar horizontal structural pattern that is quite different from the pattern shared by both of the Vietnamese groups suggests that the spatial layout of homegardens is strongly influenced by their different cultural models.

  1. 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.

  2. 农地流转对农业生态系统的影响%Impact of farmland transfer on agro-ecosystem

    Institute of Scientific and Technical Information of China (English)

    程相友; 信桂新; 陈荣蓉; 李承桧

    2016-01-01

    Farmland transfer, supported by both the national and local governments, has largely promoted the transformation of agricultural management and modernization. Specifically, the increasing scope and scale of farmland transfer dramatically changed the industrial structure and input-output of agriculture. Thus farmland transfer has a significant effect on the agro-ecosystem. To assess eco-environmental effects of the transformation of the mode of agricultural management due to farmland transfer, this study analyzed three aspects of farmland transfer ― production efficiency, environmental impact and overall sustainability of agro-ecosystems. This was done in a case study of Rongchang County in Chongqing, China. To do that, the input-output of ordinary farmers and agricultural contractors, which respectively represented the agricultural management patterns before and after farmland transfer, was analyzed. The emergy evaluation method used proved to be effective in analyzing the efficiency and sustainability of ecosystems. Emergy evaluation method overcame the weakness of traditional methods of energy analysis as it integrated different forms of energy into a common physical basis known as solar emergy. This method took multiple important factors into consideration (e.g., natural resources, labor and ecosystem services), generally neglected in other similar methods. The results showed that the input for purchasing resources decreased by 70.48%while emergy output increased by 2.15% after farmland transfer. Thus emergy yield ratio (EYR) changed from 0.01 before farmland transfer to 0.04 after that, which represented an increase of 300.00%. This increase was mainly due to agricultural machinery input rather than labor force input, which lowered the overall input and increased the efficiency of production. For a single input item, when its’ renewability factor was less than that of the ecosystem, decreasing input reduced the environmental loading ratio (ELR); for the

  3. Contribution of different aquatic habitats to adult Anopheles arabiensis and Culex quinquefasciatus (Diptera: Culicidae) production in a rice agroecosystem in Mwea, Kenya.

    Science.gov (United States)

    Mwangangi, Joseph M; Muturi, Ephantus J; Shililu, Josephat; Muriu, Simon M; Jacob, Benjamin; Kabiru, Ephantus W; Mbogo, Charles M; Githure, John; Novak, Robert

    2008-06-01

    Studies were conducted to determine the contribution of diverse larval habitats to adult Anopheles arabiensis Patton and Culex quinquefasciatus Say production in a rice land agro-ecosystem in Mwea, Kenya. Two sizes of cages were placed in different habitat types to investigate the influence of non-mosquito invertebrates on larval mortalities and the contribution of each habitat type to mosquito productivities, respectively. These emergence traps had fine netting material covers to prevent adult mosquitoes from ovipositing in the area covered by the trap and immature mosquitoes from entering the cages. The emergence of Anopheles arabiensis in seeps, tire tracks, temporary pools, and paddies was 10.53%, 17.31%, 12.50%, and 2.14%, respectively, while the corresponding values for Cx. quinquefasciatus were 16.85% in tire tracks, 8.39% in temporary pools, and 5.65% in the paddies from 0.125 m3 cages during the study. Cages measuring 1 m3 were placed in different habitat types which included paddy, swamp, marsh, ditch, pool, and seep to determine larval habitat productivity. An. arabiensis was the predominant anopheline species (98.0%, n = 232), although a few Anopheles coustani Laveran (2.0%, n = 5) emerged from the habitats. The productivity for An. arabiensis larvae was 6.0 mosquitoes per m2 for the temporary pools, 5.5 for paddy, 5.4 for marsh, 2.7 for ditch, and 0.6 for seep. The Cx. quinquefasciatus larval habitat productivity was 47.8 mosquitoes per m2 for paddies, 35.7 for ditches, 11.1 for marshes, 4.2 for seeps, 2.4 for swamps, and 1.0 for temporary pools. Pools, paddy, and marsh habitat types were the most productive larval habitats for An. arabiensis while paddy, ditch, and marsh were the most productive larval habitats for Cx. quinquefasciatus. The most common non-mosquito invertebrate composition in the cages included Dytiscidae, Notonectidae, Belostomatidae, and Ephemerellidae, and their presence negatively affected the number of emergent mosquitoes from

  4. Regional and field-specific factors affect the composition of fusarium head blight pathogens in subtropical no-till wheat agroecosystem of Brazil.

    Science.gov (United States)

    Del Ponte, Emerson M; Spolti, Piérri; Ward, Todd J; Gomes, Larissa B; Nicolli, Camila P; Kuhnem, Paulo R; Silva, Cleiltan N; Tessmann, Dauri J

    2015-02-01

    A multiyear survey of >200 wheat fields in Paraná (PR) and Rio Grande do Sul (RS) states was conducted to assess the extent and distribution of Fusarium graminearum species complex (FGSC) diversity in the southern Brazilian wheat agroecosystem. Five species and three trichothecene genotypes were found among 671 FGSC isolates from Fusarium head blight (FHB)-infected wheat heads: F. graminearum (83%) of the 15-acetyldeoxynivalenol (15-ADON) genotype, F. meridionale (12.8%) and F. asiaticum (0.4%) of the nivalenol (NIV) genotype, and F. cortaderiae (2.5%) and F. austroamericanum (0.9%) with either the NIV or the 3-ADON genotype. Regional differences in FGSC composition were observed, with F. meridionale and the NIV type being significantly (P28%) than in RS (≤9%). Within RS, F. graminearum was overrepresented in fields below 600 m in elevation and in fields with higher levels of FHB incidence (Pcomposition was not significantly influenced by previous crop or the stage of grain development at sampling. Habitat-specific differences in FGSC composition were evaluated in three fields by characterizing a total of 189 isolates collected from corn stubble, air above the wheat canopy, and symptomatic wheat kernels. Significant differences in FGSC composition were observed among these habitats (P96%) of isolates from corn stubble, whereas F. graminearum with the 15-ADON genotype was dominant (>84%) among isolates from diseased wheat kernels. Potential differences in pathogenic fitness on wheat were also suggested by a greenhouse competitiveness assay in which F. graminearum was recovered at much higher frequency (>90%) than F. meridionale from four wheat varieties inoculated with an equal mixture of F. graminearum and F. meridionale isolates. Taken together, the data presented here suggest that FGSC composition and, consequently, the trichothecene contamination in wheat grown in southern Brazil is influenced by host adaptation and pathogenic fitness. Evidence that F

  5. Banco de sementes e estabelecimento de plantas daninhas em agroecossistemas Seed bank in the soil and the establishment of weeds in agro-ecosystems

    Directory of Open Access Journals (Sweden)

    Ricardo Carmona

    1995-01-01

    Full Text Available Em novembro/92 o banco de sementes no solo foi estimado, a 0-10 cm de profundidade, em alguns agroecossistemas: área de rotação de culturas, várzea, pomar de cítrus e pastagem de Brachiaria brizantha, no Distrito Federal, Brasil. Esta estimativa foi realizada através da observação da emergência de plântulas em amostras de solo incubadas, com e sem lavagem através de peneira e presença ou ausência de nitrato de potássio. A lavagem do solo para redução de volume, seguida de utilização de nitrato de potássio, mostrou-se desvantajosa para a determinação dos bancos de sementes viáveis detectadas nas amostras. A quantidade média de sementes por metro quadrado foi de 22313 na várzea, 6768 na área de rotação, 3595 nas coroas do pomar e 529 na pastagem. Verificou-se que as plantas infestantes estabelecidas em maio/93 nos agroecossistemas, representavam, em relação á quantidade inicial de sementes: 0,34% na pastagem, 0,71% na várzea, 1,48% nas coroas do pomar e 1,56% na área de rotação de culturas. Estas plantas seriam aquelas que supostamente mais contribuíram para a manutenção dos bancos de sementes no solo. Houve uma correlação direta do banco de sementes com o número de espécies e indivíduos presentes nos agroecossistemas. As espécies predominantes nas áreas anualmente perturbadas foram Ageratum conyzoides, Bidens pilosa, Cenchrus echinatus, Commelina benghalensis, Emilia sonchifolia, Euphorbia heterophylla e Richardia brasiliensis. Brachiaria spp predominou nas entrelinhas do pomar, enquanto na pastagem as poucas plantas daninhas presentes eram espécies de cerrado. A similaridade entre agroecossistemas, com relação às plantas daninhas foi maior entre as áreas mais perturbadas, como áreas de rotação de culturas, várzea e coroas do pomar.The seed bank in the soil was estimated in November/92 at 0-10 cm depth in some agro-ecosystems: arable land, meadow land, citrus orchard and a Brachiaria brizantha

  6. Effects of Simulated Nitrogen Deposition on Soil Macrofauna in Agroecosystem%模拟氮沉降对农田大型土壤动物的影响

    Institute of Scientific and Technical Information of China (English)

    荣海; 范海兰; 李茜; 李键; 洪伟; 吴承祯

    2011-01-01

    A simulated nitrogen deposition experiment was conducted in the agroecosystem of Curcuma aromatica cv. wenyujin.The treatments were designed by different rates of nitrogen application: CK ( without nitrogen application ), Ts0( 50 kg ·hm-2 · a-1 ), T00( 100 kg · hm-2 · a-1 ) and T150( 150 kg · hm-2 · a-1 ). Soil macrofauna in the agroecosystem was assessed after 5 months. Results showed that a total of 485 soil animals were recorded, belonging to 19 groups. The dominant groups were Oligochaeta and Hymenoptera, and the number of common groups was 8 and that of rare groups was 9. The numbers of both group and individual reached their maximun values in the 0-5 cm soil layer. Nitrogen deposition changed the surface gathering of the individual nunber of soil macrofauna, and the soil animals treated by high nitrogen level tended to dodge into deeper soil layers. Nitrogen deposition reduced the individual nunber. The CK showed the highest nunber, followed by T100 and T150 in the 0-5 cm layer. Nitrogen deposition had little effect on the vertical distribution of group nunber of soil animals, but it reduced the group nunber. CK showed the highest group nunber, followed by T100 and T150 in the 0-5 cm layer. Shannon-Weiner diversity- index, Pielou evenness index and Simpson dominance index of different treatments showed similar trends, namely T100 >T50 >CK>T150, which indicated that nitrogen deposition increased the diversity- of soil animals treated by low N level, but decreased it at high nitrogen level. The diversity- of soil macrofauna showed a strong positive corelation with fresh weight of weed ( r = 0.74 ); furthermore, the fresh weight of weed had a strong negative corelation with C. aromatica cv. wenyujin ( r = -0.79 ). The responses of soil macrofauna to nitrogen deposition are likely to be a more complex process affected by weed and crops.%采用喷施氮肥模拟氮沉降的方法,分对照(CK,不施氮)、低氮(T50,50 kg·hm-2·a-1)、中氮(T100

  7. Emergy of agro-ecosystem in Hunan Province: Evolution and trend%湖南省农业生态系统能值演变与趋势

    Institute of Scientific and Technical Information of China (English)

    朱玉林; 李明杰

    2012-01-01

    应用能值分析方法,对1999-2008年湖南省农业生态系统的能值总量、投入和产出结构以及各能值指标的变化进行趋势分析.结果表明:研究期间,湖南省农业生态系统总能值使用投入量基本保持平稳,但能值投入结构有变化,其中,不可更新工业辅助能值投入量由4.00E+22 sej增至5.53E+22 sej,可更新有机能值投入量由1.32E+23 sej降至1.20E+23 sej;系统能值产出总量和产出效率均有较大幅度的提高,2008年总能值产出达1.69E+23 sej,比1999年提高23.8%,净能值产出率由0.79升至0.96;由于环境负载率也呈不断上升的趋势(由1.12上升到1.79),可持续发展指数呈缓慢下降趋势,由0.71降至0.54,说明湖南省农业总体属于高消费驱动型生态系统,具有较明显的粗放式发展特征.%By using emergy analysis method, a trend analysis was made on the total emergy, its input-output structure, and emergy indices of the agro-ecosystem in Hunan Province of South-central China from 1999 to 2008. In the study period, the available total emergy input of the ecosystem was basically maintained at a stable level, but the input structure changed with the input of non-renewable industrial auxiliary emergy increased from 4. 00E+22 sej in 1999 to 5. 53E+22 sej in 2008, while that of renewable organic emergy decreased from 1.32E+23 sej to 1.20E+23 sej. Both the total emergy output and the output efficiency of the ecosystem had a great increase, with the total output reached 1. 69E+23 sej in 2008, which was 23.8% higher than that in 1999, and the net output ratio increased from 0. 79 to 0.96. Owing to the ever-increasing trend of the environmental loading ratio which was from 1.12 to 1.79, the sustainable development index of the ecosystem presented a decreasing trend, from 0.71 to 0.54, indicating that the agriculture in Hunan Province was overall belonged to the type of ecosystem driven by high consumption, and had relatively apparent extensive

  8. Evaluation of Two Mycorrhiza Species and Nitroxin on Yield and Yield Components of Garlic (Allium sativum L. in an Ecological Agroecosystem

    Directory of Open Access Journals (Sweden)

    P Rezvani Moghaddam

    2016-02-01

    Full Text Available Introduction Maintenance of soil fertility is one of the most important issues affecting the sustainability of food production. The application of ecological inputs such as mycorrhiza and biofertilizers are one of those approaches which are needed to maintain soil fertility Biofetilizers include different types of free living organisms that convert unavailable nutrients to available forms and enhance root development and better seed germination. Plant growth promoting rhizobacteria (PGPR occupy the rhizosphere of many plant species and have beneficial effects on the host plant. They may directly and indirectly influence the plant growth. A direct mechanism would be to increase plant growth by supplying the plant with nutrients and hormones. Indirect mechanisms, on the other hand, include reduced susceptibility to diseases and acting as a form of defense referred to as induces systematic resistance. Mycorrhiza arbuscular fungi are other coexist microorganisms that improve soil fertility, nutrients cycling and agroecosystem health. Mycorrhizal fungi are the most abundant organisms in agricultural soils. Many researchers have pointed to the positive roles of mycorrhizal fungi on plants growth characteristics. Arbuscular mycorrhizas are found in 85% of all plant families and occur in many crop species. Mineral nutrients such as potassium, calcium, copper, zinc and iron are assimilated more quickly and in greater amounts by mycorrhizal plants. Arbuscular mycorrhizal inoculation has also been shown to increase plant resistance of pathogen attack. Garlic (Allium sativum L. is a very powerful medicinal plant that is often underestimated. Garlic is easy to grow and can be grown year-round in any mild climates. Garlic cloves are used for consumption (row and cooked or for medicinal purposes. They have a characteristic pungent, spicy flavor that mellows and sweetens considerably with cooking. Despite of many studies on the effects of mycorrhiza and

  9. Big Data Initiatives for Agroecosystems

    Science.gov (United States)

    NAL has developed a workspace for research groups associated with the i5k initiative, which aims to sequence the genomes of all insesct species known to be important to worldwide agriculture, food safety, medicine, and energy production; all those used as models in biology; the most abundant in worl...

  10. 东北粮食主产区农业生态系统健康格局与因子诊断——以吉林省为例%Spatial-temporal pattern and factor diagnoses of agroecosystem health in major grain producing areas of Northeast China: A case study in Jilin Province

    Institute of Scientific and Technical Information of China (English)

    赵宏波; 郑辉; 苗长虹; 邵田田; 冯渊博

    2016-01-01

    It is of great significance to study agroecosystem health in major grain producing areas based on the theory and method of ecosystem health.This paper selected Jilin Province as the study area,and an evaluation index system of agroecosystem health was built based on the SSI-VOR conceptual framework model.Using the optimal combined weights method,comprehensive evaluation assessment,GIS spatial analysis and grey slope similarity incidence models,the spatial-temporal pattern of agroecosystem health and influence factors were analyzed from 2000 to 2011 in Jilin Province.The results indicated that,temporally,the composite index of agroecosystem health showed a rising trend in Jilin Province from 1995 to 2011,and the agroecosystem health level changed from not healthy to relatively healthy;spatially,the spatial discrepancy of agroecosystem health level tended to become larger,which remained unchanged in central area,while was gradually improved in southeast and west.The main contributors which improved the agroecosystem health level were economic driving force,environmental management and social development,while the main ‘dragging’ factors were ecological pressure,organization structure and input capacity.Finally,relevant measures were put forward to improve the agroecosystem health condition.%运用生态系统健康的理论与方法研究粮食主产区农业生态系统健康问题具有重要的意义,以东北粮食主产区的典型区域吉林省为研究对象,基于构建的胁迫-状态-免疫(S-S-I)与活力-结构组织-恢复力(V-O-R)农业生态系统健康评价指标体系,运用最优组合赋权法、综合评价模型、GIS空间分析技术和灰色斜率相似关联度诊断模型对2000-2011年吉林省农业生态系统健康的时空格局以及影响因子进行分析.结果表明:时间特征上,2000-2011年吉林省农业生态健康等级从“不健康级”状态向“较健康级”状态转变,农业生态系统健康水平

  11. Escoamento superficial em Latossolo Amarelo distrófico típico sob diferentes agroecossistemas no nordeste paraense Runoff in Oxisol under different agroecosystems in the northeast part of Pará State

    Directory of Open Access Journals (Sweden)

    Cristiane F. G. da Costa

    2013-02-01

    Full Text Available Na bacia dos igarapés Timboteua e Buiuna, no Estado do Pará, avaliou-se a influência das mudanças de uso da terra e do manejo do solo sobre as taxas de escoamento superficial. Foram estabelecidas 18 parcelas experimentais (1 m² sendo três em cada um dos seis agroecossistemas avaliados, a saber: i Capoeira de 20 anos (CP; ii Sistema agroflorestal / derruba-e-queima (SQ; iii Sistema agroflorestal / corte-e-trituração (ST; iv Cultivo de mandioca / corte-e-trituração - Roça (RT; v Cultivo de mandioca / derruba-e-queima - Roça (RQ; vi Pastagem / derruba-e-queima (PQ. Adicionalmente foram instalados, na mesma localidade, dois pluviômetros e três coletores de água de chuva (CH para monitoramento da precipitação. Em 26 datas ao longo da estação chuvosa de 2010, foram coletadas 234 amostras, obtendo-se alta correlação entre volumes precipitado e escoado. O agroecossistema de Pastagem (PQ degradada apresentou o maior valor de 54,53% do total de escoamento superficial medido nesta pesquisa, e o SAF, que estava em recuperação de 7 anos após uma queima, o menor valor de 1,11%. O escoamento superficial decresceu dos agroecossistemas de menor para os sistemas de maior percentagem de material orgânico.In the watershed of the Timboteua and Buiuna streams in the State of Pará, the effect of land use change and soil management on the runoff rates was evaluated. Eighteen experimental plots (1 m² were established, three in each one of the six evaluated agroecosystems as follows: i 20 years Secondary vegetation ("Capoeira" (CP, ii Agroforestry system / slash-and-burn (SQ, iii Agroforestry system / chop-and-mulch (ST, iv Cassava crop / chop-and-mulch (RT, v Cassava crop / slash-and-burn (RQ, vi Cattle pasture / slash-and-burn (PQ. Nearby these plots two rain gauges and three rainwater collectors for monitoring of precipitation were also installed. Along 2010 rainy season 234 samples were collected on 26 different dates. A strong correlation

  12. Energy efficiency of physic nut agroecosystems: comparative between the dried and irrigated system; Eficiencia energetica do agroecossistema pinhao-manso: comparativo entre os sistemas de cultivo de sequeiro e irrigado

    Energy Technology Data Exchange (ETDEWEB)

    Frigo, Michelle Sato [Universidade Federal de Mato Grosso do Sul (CPCS/UFMS), Chapadao do Sul, MS (Brazil)], E-mail: msfrigo@nin.ufms.br; Bueno, Osmar de Carvalho; Esperancini, Maura Seiko Tsuitsui [Universidade Estadual Paulista (FCA/UNESP), Botucatu, SP (Brazil). Fac. de Ciencias Agronomicas. Dept. de Gestao e Tecnologia Agroindustrial; Frigo, Elisandro Pires [Universidade do Oeste Paulista (CCET/UNIOESTE), Cascavel, PR (Brazil). Centro de Ciencias Exatas e Tecnologicas; Klar, Antonio Evaldo [Universidade Estadual Paulista (FCA/UNESP), Botucatu, SP (Brazil). Fac. de Ciencias Agronomicas. Dept. de Engenharia Rural

    2009-07-01

    The physic nut have been a major object of study oil seeds to produce biofuel, but their productive characteristics and the energy expenditure for their production are largely unknown to national both and international conditions. The purpose of this study was to evaluate the efficiency of the physic nut agroecosystem in two different production systems: irrigated and dried. The plantations areas were selected of the company NNE Minas Agro Florestal Ltda. of Janauba/MG. The preparation of the study began with the restoration of the route through the technical oral report provided by the company. Ten operations were identified in the irrigated system and six operations in the dried system. The methodology adopted was based on literature review. The energy balance was 2,141.66 MJ. ha{sup -1} for the irrigation system and 319.30 MJ. ha{sup -1} for the dried. The energy efficiency index for the irrigation system was 2.77 and was not possible to calculate the dried system because this indicator does not use fossil sources. It was concluded that in both systems were used larger amounts of energy to produce than the energy obtained by the final product. (author)

  13. 显花植物在提高节肢动物天敌控制害虫中的生态功能%Ecological Functions of Flowering Plants on Conservation of the Arthropod Natural Enemies of Insect Pests in Agroecosystem

    Institute of Scientific and Technical Information of China (English)

    朱平阳; 吕仲贤; Geoff Gurr; 郑许松; Donna Read; 杨亚军; 徐红星

    2012-01-01

    由于农业集约化生产引起的非作物生境减少和农业化学品的过量使用减弱了农田生态系统中害虫天敌的自然控制作用。合理而有效地利用显花植物可以为害虫天敌提供食物来源和庇护场所,从而能有效地提高天敌对害虫的自然控制能力、减少化学农药的使用量。本文综述了显花植物对天敌种群的促进作用及其在果园、蔬菜和粮食作物等害虫防治中应用的最新进展,同时对进一步利用显花植物提高农业生态系统稳定性的发展方向进行了讨论。%Intensive crop production and overuse of agrochemicals, including fertilizer and pesticides, has resulted in reduction of non-crop habitats, simplification of farm landscape, sharp decline of biodiversity, and decrease of the biological control capacities of arthropod natural enemies of insect pests in agroecosystem. Effective and rational utilization of flowering plants that provide food sources and shelters for natural enemies can strongly improve natural control function and may reduce application of chemical pesticides. This review presented the nutritional function of plant flowers for natural enemies, and the practical applications of flowering plants in agroecosystems such as orchards, vegetable gardens and food crops. Prospective in utilization of flowering plants and potential agricultural measures for maximizing natural control of insect pests in agroecosystem was also discussed.

  14. Soil attributes under agroecosystems and forest vegetation in the coastal tablelands of northestern Brazil Atributos de solo de agroecossistemas e coberturas florestais dos tabuleiros costeiros do nordeste do Brasil

    Directory of Open Access Journals (Sweden)

    João Bosco Vasconcellos Gomes

    2012-12-01

    Full Text Available This study evaluated the changes occurred in a set of soil attributes, particularly those related to the dynamics of soil organic carbon (SOC, as a function of the replacement of native forest for agricultural ecosystems of regional importance in the coastal tablelands of Northeastern Brazil (orange, coconut, eucalyptus and sugarcane. Six commercial sites under these agroecosystems were compared to neighboring areas of native forest in five areas along this region (Coruripe, Umbaúba, Acajutiba, Cruz das Almas and Nova Viçosa. Soil samples were taken from 0-5 and 5-20 cm depth and analyzed for particle size distribution, bulk density, organic C (OC, particulate organic matter, C in soil solution, microbial biomass C, total cation exchange capacity and water stable aggregates. Linear correlation and multivariate techniques were used for data analysis. The values of base saturation and Al saturation for the 0-20 cm depth layer were also calculated. In all the studied areas, soils under native forest presented better status of physical and chemical attributes than their agroecosystem counterparts, especially in the 0-5 cm layer. For both layers, OC content was the attribute most strongly correlated with the overall changes in all attributes. Unexpectedly, the OC content showed no significant correlation with the sum of silt and clay contents. The set of variables investigated in this study is sensitive to differentiate the quality of soils under perennial and semi-perennial land uses from their counterparts under natural vegetation in the landscapes of the coastal tablelands of Northeastern Brazil.Este trabalho avaliou as alterações de um conjunto de atributos de solos dos tabuleiros costeiros do Nordeste do Brasil, em especial os relacionados à dinâmica do C orgânico (CO, em função da substituição da vegetação florestal nativa por agroecossistemas de importância regional (laranja, coco, eucalipto e cana-de-açúcar. Seis s

  15. Soil Carbon Storage and N{sub 2}O Emissions from Wheat Agroecosystems as Affected by Free-Air CO{sub 2} Enrichment (FACE) and Nitrogen Treatments. Annual Progress Report - Year 1: August 1, 1996 to July 31, 1997 [Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Leavitt, S.W.; Matthias, A.; Thompson, T.L.

    1999-02-17

    Rising atmospheric CO{sub 2} concentrations have prompted concern about response of plants and crops to future elevated CO{sub 2} levels, and particularly the extent to which ecosystems will sequester carbon and thus impact the rate of rise of CO{sub 2} concentrations. Free-air CO{sub 2} enrichment (FACE) experimentation was used with wheat agroecosystems for two growing seasons to assess effects of CO{sub 2} and soil nitrogen. Over 20 researchers on this experiment variously examined plant production and grow yield, phenology, length of growing season, water-use efficiency, ecosystem productivity, below ground processes (root and microbial activity, carbon and nitrogen cycling), etc.

  16. A Multi-Year Comparison of No-Till Versus Conventional-Till Effects on the Carbon Balance in a Corn/Soybean Agro-Ecosystem Using Eddy Covariance

    Science.gov (United States)

    Joo, E.; Slattery, R.; Meyers, T. P.; Bernacchi, C.

    2015-12-01

    Dramatic increases in atmospheric CO2 concentrations since the industrial revolution are in large part due to the release of carbon previously stored in the soil. No-till strategies have been proposed as a means to mitigate agricultural contributions to atmospheric carbon by decreasing emissions and sequestering carbon in agricultural soils while increasing water use efficiency and soil quality. However, the effects of no-till versus conventional-till practices on carbon sequestration often vary due to difficulty in quantifying soil carbon as soil properties change with management. Eddy covariance (EC) offers a more accurate method of continuously measuring the total carbon budget and does so without relying on physical soil carbon measurements. The majority of agricultural land in the Midwestern United States is farmed using the corn/soybean rotation, making it an ideal agro-ecosystem to examine the potential of adopting no-till practices on carbon and water balances. In this study, we use EC to compare carbon and water fluxes between continuous no-till and conventional-till corn/soybean sites over several years in east central Illinois. This allows the determination and comparison of 1) net ecosystem exchange (NEE) and net biome production (NEE after accounting for grain usage); 2) water use efficiency; and 3) response to climatic variation, both at short and long time scales, between the two tillage systems. We hypothesize that both carbon uptake and water use efficiency will improve with no-till practices, which in turn will improve crop responses to environmental factors such as drought and heat stress.

  17. A simplified method for the assessment of carbon balance in agriculture: an application in organic and conventional micro-agroecosystems in a long-term experiment in Tuscany, Italy

    Directory of Open Access Journals (Sweden)

    Giulio Lazzerini

    2014-06-01

    Full Text Available Many research works propose sophisticated methods to analyse the carbon balance, while only a few tools are available for the calculation of both greenhouse gas emissions and carbon sequestration with simplified methods. This paper describes a carbon balance assessment conducted at farm level with a simplified methodology, which includes calculations of both CO2 emissions and carbon sequestration in crop rotations. This carbon balance was tested in the Montepaldi Long Term Experiment (MOLTE trial in central Italy, where two agroecosystems managed with two different farming practices (organic vs conventional are compared. Both in terms of CO2eq emissions and carbon sequestration, this simplified method applied in our experiment provided comparable results to those yielded by complex methodologies reported in the literature. With regard to the crop rotation scheme applied in the reference period (2003-2007, CO2 emissions from various farm inputs were found to be significantly lower (0.74 Mg ha-1 in the organically managed system than in the conventionally managed system (1.76 Mg ha-1. The same trend was observed in terms of CO2eq per unit of product (0.30 Mg kg-1 in the organic system and 0.78 Mg kg-1 in the conventional system. In the conventional system the sources that contributed most to total emissions were direct and indirect emissions associated with the use of fertilisers and diesel fuel. Also the stock of sequestered carbon was significantly higher in the organic system (27.9 Mg ha-1 of C than in the conventional system (24.5 Mg ha-1 of C. The carbon sequestration rate did not show any significant difference between the two systems. It will be necessary to test further this methodology also in commercial farms and to validate the indicators to monitor carbon fluxes at farm level.

  18. 湖南农业生态系统的能值效率与结构调整%Emergy Efficiency and Structural Adjustment of Hunan Agro-ecosystem

    Institute of Scientific and Technical Information of China (English)

    侯茂章; 朱玉林

    2012-01-01

    [目的】分析1980-2010年湖南农业生态系统的产出效率。[方法]本文主要采用能值方法来评估湖南农业生态系统的能值投入与产出。[结果]研究期间湖南农业生态系统的能值总投入增长主要是由各类辅助能投入增加导致的。不可再生的工业辅助能值投人占总辅助能值投入的比例从1980年的21.80%4升到2010年的33.04%。研究期间湖南农业生态系统的能值总产出增加了2.43倍,其中畜牧业和渔业的能值产出总能值产出的比率大幅增加,而种植业和林业的能值产出占总能值产出的比率有一定程度下降。[结论]湖南农业生态系统的能值产出率有所改善,但其可持续性并不乐观。%[Objective] To analyze the efficiency of Hunan agro-ecosystem in 1980- 2010. [Method] This paper adopts the emergy methods to evaluate the emergy input and output. [Result] The growth of total emergy input was mainly caused by the auxiliary factors in this phase. The proportion of the nonrenewable purchased emergy input to the total auxiliary emergy input increased from 21.80% in 1980 to 33.04% in 2010. In 1980-2010 the total emergy output of the system increased by 2.43 times, the proportions of the stock farming emergy output and fishery emergy output to the total emergy output increased sharply, while those of the planting emergy output and forestry emergy output showed a considerable decline. [Conclusion] The emergy yield ratio of this system was improved but its sustainability was worrying.

  19. CARACTERIZACIÓN Y EVALUACIÓN DE AGROECOSISTEMAS A ESCALA PREDIAL. UN ESTUDIO DE CASO: CENTRO AGROPECUARIO PAYSANDÚ (MEDELLÍN, COLOMBIA CHARACTERIZATION AND EVALUATION OF AGROECOSYSTEMS ON A FARM SCALE A STUDY CASE: THE PAYSANDÚ FARMING CENTER.

    Directory of Open Access Journals (Sweden)

    Juan Camilo de los Rios Cardona

    2004-12-01

    Full Text Available Se caracteriza y evalúa el estado, condición y tendencia, de los Agroecosistemas (AE del Centro Agropecuario Paysandú de la Universidad Nacional de Colombia, Sede Medellín, mediante la parametrización y análisis de las variadas Receptividad Tecnológica (RT e Intensidad Tecnológica (IT, con base en la propuesta metodológica de Vélez y Gastó (1979, en cuanto a la diversidad de AE y de usos, manejo y acogida tecnológica, dotación en tecnoestructura e hidroestructura, potencial productivo y servicios a la sociedad local regional y nacional. Los resultados muestran que la mayor parte del área del Centro (72% tiene RT Muy Baja, la cual no admite el establecimiento de Sistemas de Manejo Agrotecnológico (SMA Mecanizados Avanzados. Sin embargo, el 69.8% del área es manejada con SMA adecuados para las restricciones que impone la RT. El 62% del área del Centro, principalmente bajo cobertura de pradera para ganadería de leche, es manejada con SMA avanzado. Como producto de la interacción entre RT y los SMA utilizados, se encontraron seis AE, de los cuales, tres, que representan el 69,8% del área ( 100,2 ha., se manejan con tecnologías adecuadas a sus condiciones biofísicas o de receptividad tecnológica (IT Adecuada, y los otros tres, que representan el 28,57% del área ( 41,3 ha., son manejados con tecnologías que no se corresponden con sus condiciones de RT (IT tradicional, lo que conlleva al deterioro de sus condiciones biofísicas y ecológicas.The state, condition, and tendencies of the agro-ecosystems (AE of the Paysandú Farming Center of the Universidad Nacional de Colombia, Sede Medellín were characterized and evaluated by means of parameterization and analysis of the various Technological Receptivity (RT, after the Spanish initials and Technological Intensity (IT, based upon a methodological proposal of Vélez and Gastó (1999, in terms of AE diversity and of the uses, management, and technological acceptance

  20. 从农业生态系统承载力看全球生态经济系统前景%The Perspective of Global Economic Ecosystem Based on the Capacity of Agro-ecosystem

    Institute of Scientific and Technical Information of China (English)

    梁颖; 廖承红; 蔡承智

    2011-01-01

    The yield potentials of crops were projected in this research by three different methods: (1) the yield potentials of the majority of global crops were projected by the regression analysis of the historical annual crop yield data to be 2 to 3 times of their current yields; (2) the yield potentials of rice, wheat, maize, potato,rapeseed and soybean for China were projected by the AEZ model developed by IIASA and FAO to be 1.2, 2.2,2.2, 2.9, 2.0 and 1.9 times of their 2005 country-wide average respectively; (3) the yield potentials of global rice, wheat, maize, potato, rapeseed and soybean were projected to be 1.4, 2.5, 1.2, 1.8, 1.9 and 2.2 times of their present record yield respectively, by the maximum light use efficiency (LUE) of plant model. The projected potential crop yields of the study indicated that the carrying capacity of global agro-ecosystem was limited. Thus, in a closed system such as the global ecological and economical system was not sustainable.%本研究运用3种方法预测作物产量潜力,结果表明:(1)利用作物历年单产回归拟合后进行趋势外推,得出多数作物的未来产量潜力极限大约是现在单产的2~3倍;(2)运用国际应用系统研究所(IIASA)与"联合国粮农组织"(FAO)共同开发的"农业生态区划"(AEZ)模型计算中国主要粮油作物的区域单产最高潜力,得出水稻、小麦、玉米、马铃薯、油菜和大豆的单产潜力分别是它们2005年全国平均单产的1.2倍、2.2倍、2.2倍、2.9倍、2.0倍、1.9倍;(3)运用自然界中植物的最大光能利用率计算世界主要粮油作物单产的光合潜力,得出水稻、小麦、玉米、马铃薯、油菜、大豆产量的最大光合生产潜力大约分别是目前高产地区单产的1.4倍、2.5倍、1.2倍、1.8倍、1.9倍、2.2倍.据此:从作物产量潜力极限出发,阐述了农业生态系统的承载力;再从"封闭"系统特性出发,论述了全球生态经济系统的不可持续性.

  1. Quantitative Input of Atmospheric Nitrogen to an Agro-ecosystem in a Typical Red Soil Region%大气氮沉降向典型红壤区农田生态系统定量输入研究

    Institute of Scientific and Technical Information of China (English)

    崔键; 周静; 杨浩; 梁家妮; 刘晓利

    2009-01-01

    The atmospheric nitrogen (N) deposition flux and dry deposition N velocities ( V_d) were estimated using big leaf resistance analogy model by observations of onflow and factors of farmland microclimate, analysis of nitrides from the atmosphere and rain in an agro-ecosystem, a typical red soil region on Experiment Station of Red Earth Ecology, Chinese Academy (Yingtan, Jiangxi) of Sciences in 2005. The results showed that the dry deposition N was 82.63 kg·hm~(-2) , accounting for 67.94% of the total N, which was 132.6 k·hm~(-2) in the whole year (2005) . In N dry deposition progress, NH_3-N and N0~-_3 -N were the main settlement for gas and particle, respectively. NH_3-N was made up 43.02% to 89.89% (mean value, 71.05%) of the gaseous N deposition while N0~-_3 -N was accounted for 33.67% to 94.54% (mean value, 61.01% ) of the particle N deposition. The N wet deposition fluxes were 0.50-8.45 kg·hm~(-2) per month and reached the higher value in July and November.%在2005年,通过对中国科学院红壤生态实验站(江西鹰潭)内农田小气候要素和湍流的观测及大气和雨水中氮化物的分析,借助大叶阻力相似模型,研究了大气氮素(N)通过干、湿沉降输入研究地农田生态系统的N通量.结果表明,全年通过大气沉降向该农田生态系统输入N 132.6 kg·hm~(-2),其中干沉降输入N 82.63 kg·hm~(-2),占大气总输入N的67.94%.干沉降过程中,气体中以NH_3-N沉降为主,占气态N沉降的43.02%~89.89%(均值为71.05%);颗粒中以NO~-_3-N为主,占颗粒态N的33.67%~94.54%(均值为61.01%).每月通过湿沉降(雨水)输入N 0.50~8.45 kg·hm~(-2),以7月和11月较高.

  2. Microorganismos asociados a la rizosfera de jitomate en un agroecosistema del valle de Guasave, Sinaloa, México Rhizosphere microorganisms associated to tomato in an agroecosystem from Guasave Valley, Sinaloa, Mexico

    Directory of Open Access Journals (Sweden)

    Jesús Damián Cordero-Ramírez

    2012-09-01

    diversity of culturable and non-culturable microorganisms associated to tomato (Solanum lycopersicum L. in an agroecosystem from Sinaloa. Genomic DNA from rhizospheric soil was extracted and a hypervariable region on the rDNA was amplified using universal oligonucletides directed to amplify prokaryotic and eukaryotic rDNA. Sequence analysis of 194 and 384 rDNA clones of prokaryotic and eukaryotic origin respectively showed that for eukaryotes, the most abundant phylum was Ascomycota (59%, followed by Chlorophyta (21% and Basidiomycota (12%, while for Prokaryotes, the phylum Firmicutes (45% was the most abundant followed by Proteobacteria (14.7% and Gemmatimonadetes (13.1%. This contribution represents the most complete characterization of the microorganism diversity associated to tomato rhizosphere. The work discusses the role that species belonging to genera from prokaryotic (Bacillus and Paenibacillus or eukaryotic origin (Alternaria identified on this work, could play in the rhizosphere of tomato and the biological control of phytopathogens in this species.

  3. Pilot analysis of global ecosystems: Agroecosystems

    NARCIS (Netherlands)

    Wood, S.; Sebastian, K.; Scherr, S.J.

    2000-01-01

    A joint study by International Food Policy Research Institute and World Resources Institute with Analytical Contributions from Niels H. Batjes, ISRIC; Andrew Farrow, CIAT; Jean Marc Faurès, FAO; Günther Fischer, IIASA; Gerhard Heilig, IIASA; Julio Henao, IFDC; Robert Hijmans, CIP; Freddy Nachtergael

  4. Systems approach critical to agroecosystems management

    Science.gov (United States)

    Sustainable dryland agriculture in the semi-arid Great Plains of the U.S. depends on achieving economic yields while maintaining soil resources. The traditional system of conventional tillage wheat-fallow was vulnerable to excessive soil erosion which resulted in excessive organic matter loss. No-...

  5. Ecology of entomopathogenic fungi in agroecosystems

    OpenAIRE

    Meyling, Nicolai V.

    2008-01-01

    Fungi that infect insects have received considerable attention by scientists for their potential for biological control of pests. Many research projects have focussed on the selection of virulent strains for target pests and their development as biological control agents. In contrast, surprisingly little is known about the fundamental ecology of most of these fungi in nature. This knowledge is essential in order to receive the most ecosystem services provided by entomopathogenic fungi in agri...

  6. Intercroppingenhancesagroecosystemservicesandfunctioning:Current knowledgeandperspectives*%间套作强化农田生态系统服务功能的研究进展与应用展望*

    Institute of Scientific and Technical Information of China (English)

    李隆

    2016-01-01

     ecological principles. Previous studies have shown that intercropping enhanced not only cropproductivity,butalsotheutilizationefficienciesofresources,includingabove-ground(e.g.,land,thermal,radiationandspace)andbelow-ground(e.g.,waterandnutrients)resources.Recenteffortshavemadesomeprogressesonintercroppingresearch.Here, we reviewed the potential of intercropping to strength ecosystem services and functions at the agroecosystem level,prospective research directions and highlight practical uses in modern agriculture. Intercropping increased biodiversity,productivity and stability of agroecosystems. At the same time, intercropping enhanced water use by isolating the time formaximum water requirements of one species from the other, and spatial complementarity by hydraulic lift of water. TheenhancementofnitrogenacquisitionwasattributedtonichedifferentiationofNresourcesinwhichcerealsacquiredmoremineralNfromthesoil,whilelegumesfixedmoreNfromairN2.ThiswasbecausethatcerealswasmorecompetitivethanlegumesandmineralNcompetitionincreasedsymbioticN2fixationoflegumes.SomePmobilizedspeciesfacilitatedtheconversionofsoilunavailablePintoavailableP,whichbenefitednotonlythespeciesbutalsotheneighboringimmobilizedotherspecies.E.g.,therootsoffababeanreleasedcarboxylatesorprotontodissolvesparinglysolublePinsoils.AlsotherootsofchickpeareleasedphytaseorphosphatasetodecomposeorganicPinthesoil,whichincreasedavailablesoilP.Therewereinterspecificfacilitationsofiron(Fe)andzinc(Zn)nutrientsinintercroppingofdicotyledonousornon-graminaceousmonocotyledonous(strategyIforFeacquisitionandnon-FeorZnmobilization)speciesandgraminaceousmonocotyledonous(strategy Ⅱ forFeacquisitionand Fe or Zn mobilization) species, which benefited micronutrient

  7. Processo analítico hierárquico na identificação de áreas favoráveis ao agroecossistema cafeeiro em escala municipal Analytical hierarchical process to identify favorable areas to the coffee crop agroecosystem at municipal scale

    Directory of Open Access Journals (Sweden)

    Marco Aurélio Barros

    2007-12-01

    Full Text Available O objetivo deste trabalho foi delimitar áreas favoráveis ao agroecossistema cafeeiro, em quatro municípios do Estado de Minas Gerais, pela aplicação do processo analítico hierárquico (AHP. Uma função de ponderação aritmética foi obtida, com base nas premissas de favorabilidade à cafeicultura, considerando-se as seguintes variáveis: solo, declividade, orientação de vertentes, altimetria e as possíveis áreas de preservação permanente. Essa função permitiu combinar as condições adequadas ao cultivo do café e ressaltar as áreas com maior favorabilidade. Foi verificado que os quatro municípios diferem entre si quanto à favorabilidade ao agroecossistema cafeeiro; porém, ao se considerar apenas as áreas cultivadas com café, foi verificado que os municípios de Boa Esperança e Cristais não diferem entre si.The objective of this work was to delimitate favorable areas to the coffee agroecosystem, in four municipalities of Minas Gerais State, Brazil, using the analytical hierarchical process (AHP. An arithmetic pondering function was obtained, based on the favorability premises to coffee crop production, with regard to the following variables: soil, slope, slope aspect, altimetry, and areas that should be under permanent protection. This function allowed to combine the adequate conditions to coffee crop cultivation and gave emphasis to the most favorable areas. It was observed that all four municipalities were different in terms of their favorability to the coffee agroecosystem; however, when considering only the coffee cultivated areas, it was observed that the municipalities of Boa Esperança and Cristais were not significantly different.

  8. Características edafoclimáticas e informações socioeconômicas no diagnóstico de agroecossistemas da região de São Carlos, SP Soil and climate characteristics and socio-economic data in the diagnostic of agroecosystems of São Carlos region, SP, Brazil

    Directory of Open Access Journals (Sweden)

    Luís Fernando Guedes Pinto

    2001-11-01

    Full Text Available O planejamento regional de agroecossistemas é um componente fundamental para a sustentabilidade da atividade agrícola, devendo considerar a realidade biofísica e socioeconômica. A agropecuária cumpre importante papel na região de São Carlos, SP, porém esta localiza-se em grande parte numa área de preservação ambiental. Este trabalho visou delimitar a Zona Agroecológica dessa região e diagnosticar seus agroecossistemas por meio de informações edafoclimáticas e socioeconômicas. A delimitação foi baseada no clima, geomorfologia e divisão administrativa. Da área delimitada estudou-se o clima, pedologia, uso da terra, estrutura fundiária e o manejo dos agroecossistemas. A Zona delimitada ocupa 286.824,08 ha, e é composta pelos municípios de Analândia, Itirapina, Santa Maria da Serra, São Carlos, São Pedro e Torrinha. Há potencial para a atividade agrícola, ocorrendo principalmente solos arenosos e de baixa fertilidade. Pastagens e cana-de-açúcar são os usos predominantes; a distribuição da posse da terra é desigual, e existe risco de degradação ambiental, pois não se empregam práticas compatíveis com as características naturais. Recomenda-se o uso de práticas que maximizem a conservação do solo, sua correção, e o aproveitamento de seus nutrientes, assim como o cultivo de espécies adaptadas a solos arenosos, que sejam pouco exigentes em fertilidade e resistentes a estresse hídrico.Regional planning of agroecosystems is a key component in the sustainability of agriculture and it should consider the biophysical and socio-economic reality. Agriculture plays an important role in the region of São Carlos, SP, Brazil, but it is located in an area of environmental conservation. This work aimed to delimit the Agroecological Zone of this region and to diagnose agroecosystems through soil, climate and socio-economic data. The delimitation was based on climate, geomorphology and administrative division of the

  9. Structure, function, and efficiency of agro-ecosystem around Dongting Lake region of Hunan Province, South-central China based on emergy analysis%基于能值分析的环洞庭湖区农业生态系统结构功能和效率

    Institute of Scientific and Technical Information of China (English)

    朱玉林; 李明杰; 龙雨孜; 王茂溪; 侯茂章; 李晓敏

    2012-01-01

    In order to explore the eco-efficiency of agro-ecosystem around the Dongting Lake region of Hunan Province, and to reveal the interrelationships among the human, natural resources, and environment in the ecosystem, this paper analyzed the emergy structure, func-tion , and efficiency of the agro-ecosystem, based on the emergy input-output data in 2009 and by using the emergy method of HT Odum. In the study period, this system was comparatively well developed in economy, and had a higher degree of mechanization and modernization. The fertiliz-er emergy and agricultural mechanical emergy accounted for 47. 13% and 10. 62% of the total, respectively, and the emergy density was 8.77×1011sej·hm-2 ·a-1. The system emergy output was unbalanced, planting emergy output was dominant, while forestry and fishery emergy output was comparatively low. The monetary value of per capita emergy output was 31873. 56 yuan, far greater than the per capita gross output value of regional economy in this system (24761. 14 yuan) , which indicated that the product pricing (especially the planting product pricing) of this system was evidently on the low side, and the value of natural resources and environment was not well reflected by the market. The environmental loading ratio was 1. 74, sustainable development index was 1.40, and population bearing capacity was 4. 91×105 (the agricultural population in this region was 3. 15·106) , showing that the system was full of vitality and development poten-tial , the pressure from natural resources and environment was not so high, but the system was un-der too much employment pressure and the population bearing capacity was overloading. In sum, to further reduce the price scissors between industrial and agricultural products, to keep on pro-tecting the market price of planting products, to adjust the agriculture industrial structure and product structure, and to transfer the surplus labor force would be the essential orientation of agri

  10. A review of agricultural water-saving research at Luancheng Agro-Ecosystem Experimental Station of Chinese Academy of Sciences over the last 30 years%中国科学院栾城农业生态系统试验站农田节水研究过去、现在和未来

    Institute of Scientific and Technical Information of China (English)

    张喜英

    2011-01-01

    本文回顾了中国科学院栾城农业生态系统试验站(以下简称栾城试验站)建站初期20世纪80年代以来在农田节水方面开展的研究.20世纪80年代以作物优化灌溉制度为研究重点,解决生产实际问题;20世纪90年代围绕土壤-植物-大气系统水分传输和界面调控开展了系统研究,为农田节水措施的形成提供理论基础和技术途径;近10年来进一步深化了农田节水生理生态研究,并根据多年研究积累,形成了综合节水技术模式,进行推广应用.未来栾城试验站农田节水工作将更加突出多学科渗透交叉,以提高农田水分利用效率和效益为目标,加强基础研究和节水技术的示范应用.%Farmland water-saving research was conducted since the establishment of Luancheng Agro-Ecosystem Experimental Station, Chinese Academy of Sciences (simplified as Luancheng Station). In 1980s, the research was concentrating on optimizing irrigation scheduling to reduce irrigation application for practical use. During that period, farmers usually irrigated winter wheat 7 to 10 times per season. By application an optimized irrigation scheduling, irrigation number was reduced to 5 per season without penalties to yield. In 1990s, the research was changed to fundamental studies of water movement in field. Water transfer and regulation mechanisms in soil-plant-atmosphere continuum were the research focuses during that period, resulting improved understanding of the principles and potential in water-saving. Extensive root sampling was carried out to study the pattern of root growth and soil water utilization. Root distribution down the soil profile was then modified to allow the crop to use soil water more efficiently. Evapotranspiration (ET) and soil evaporation were determined from long term data for different growing stages of winter wheat and summer maize to provide basis for crop-water relation studies. The results showed that seasonal soil water

  11. Diversidad, fluctuación poblacional y plantas huésped de escolitinos (Coleoptera: Curculionidae asociados con el agroecosistema cacao en Tabasco, México Diversity, dynamic population and host plants of bark and ambrosia beetles (Coleoptera: Curculionidae associated to the cocoa agroecosystem in Tabasco, Mexico

    Directory of Open Access Journals (Sweden)

    Manuel Pérez-De La Cruz

    2009-12-01

    Full Text Available Se estudió la diversidad de escolitinos asociados con el agroecosistema cacao en Tabasco, México durante el año 2007. Los insectos adultos fueron recolectados en 4 localidades con trampas de alcohol etílico, trampas de atracción luminosa y captura directa sobre sus plantas huésped. Se recolectaron 19 263 ejemplares, pertenecientes a 51 especies y 26 géneros. Araptus hymenaeae y Cnesinus squamosus son nuevos registros para México. La máxima diversidad de insectos capturados con los 3 métodos de recolecta se obtuvo en El Bajío (H'=2.45 y Dmg=4.83, la mínima en Río Seco (H'=2.29 y Km. 21 (Dmg=3.85, y el máximo valor de equidad (J lo obtuvo El Bajío (0.67. El índice de similitud de Sorensen (Is mostró que los sitios de estudio tienden a presentar la misma composición de especies. Los índices de diversidad, equidad y similitud, aplicados a la fauna de escolitinos capturados con cada uno de los métodos empleados, mostraron diferencias, excepto en las trampas de alcohol. La fluctuación presenta picos poblacionales marcados al inicio y al final del año de estudio. Las plantas en las que se recolectó el mayor número de especies fueron Theobroma cacao (16 y Swietenia macrophylla (13.The bark and ambrosia beetle diversity in cocoa agroecosystems was studied during 2007 in Tabasco, Mexico. Adult insects were gathered in 4 localities with ethanol and light traps and by direct collecting in their host plants. 19 263 specimens were gathered, belonging to 51 species and 26 genera. Araptus hymenaeae and Cnesinus squamosus are new records for Mexico. The maximum diversity of insects captured with the 3 collecting methods was obtained in El Bajío (H'=2.45 and Dmg=4.83, the minimum in Río Seco (H'=2.29 and Km. 21 (Dmg=3.85, and the maximum value of justness (J was obtained in El Bajío (0.67. The Sorensen similarity index (Is showed that the study places present the same species composition. The diversity, justness and similarity indices

  12. Measurement of ecotone width between agro-ecosystem and forest ecosystems after Grain for Green Program%退耕还林工程影响下农林生态系统生态交错带的宽度测定

    Institute of Scientific and Technical Information of China (English)

    王婷; 欧晓昆; 张志明; 柳小康; 王丽; 孙振华; 何彪; 李峰

    2012-01-01

    生态交错带宽度的测定是定量研究其生态过程的基础,研究利用移动分割窗技术,对退耕还林工程影响下的山地农业生态系统和森林生态系统间的生态交错带宽度进行测定.首先以对生态交错带生物多样性分布趋势有较好体现的4个多样性指数(物种丰富度、Cody指数、群落相异性系数(βJ和βS))和能体现群落本质特征的重要值为指标,取平方欧氏距离(SED)和Bray-Curtis系数(PD)为距离系数,采用移动分割窗技术分析比较.结果表明,物种丰富度,群落相异性系数βJ和βS曲线趋势具有很好的重合性,同质区间也体现得较为明显,说明这3个指标生态学意义明显,有较高的实用价值;与PD相比,SED函数划分的结果要好.然后选取物种丰富度、群落相异性系数βJ和βS作为指标以及SED作为距离系数对交错带的宽度进行测定.撂荒地-云南松林交错带位置约在样带序列25~36 m处,宽度为9 m,属于急变型交错带.%To measure the eco-tone width is fundamental to the quantitative study on the ecological processes of eco-tone.In this study,Moving Split-Window Technique(MSWT) was used to measure the eco-tone width between mountain agro-ecosystem and forest ecosystem.Four indices(Species richness,Cody,Dissimilarity coefficient and Important value) had been selected,which could reflect the change of species biodiversity in eco-tone transect gradients.In addition,Squared Euclidean distance(SED) was better than Bray-Curtis percent dissimilarity(PD) for quantifying the change of species biodiversity in the eco-tone of agricultural-forest ecosystem.The results showed that the species richness was consistent with issimilarity coefficients in the eco-tone transect.It was also indicated that the width of eco-tone of agricultural-forest ecosystems was a sharp type which spanned about 9 m.

  13. The Biogeochemical Cycling of Nitrogen in Annual and Perennial Agroecosystems

    Science.gov (United States)

    Fortuna, A.; Cogger, C.

    2010-12-01

    Organic agricultural systems are dependent upon fertilizer amendments that undergo ammonification prior to the release of plant available nitrogen (N) as ammonium. Ammonia may be further transformed via nitrification to nitrate resulting in greater potential for leaching or volatilization. Additions of plant residue and animal amendments contribute to soil N and carbon pools improving soil quality and the potential for release of ammonium. Therefore, agricultural systems that relay on organic inputs as fertilizer sources must be monitored to insure stored nutrients are released during plant uptake to prevent N losses. Our experimental design allows us to determine the effects of several organic cropping systems and fertility regimes on plant available N, nitrification potential and nitrifier gene copy number g-1 dry soil across season in a grass ley and two annual systems receiving chicken manure or compost. Nitrification potentials measured via the shaken slurry method, KCl extractable N and ammonia oxidizing bacteria (AOB) and archaea (AOA) gene copy numbers g-1 dry soil measured via quantitative PCR were monitored. Nitrification potentials measured in March revealed increases in nitrification where compost had historically been applied (7.78 vs. 5.26 ± 0.856). Treatment affects were significant in June the closest date to application of amendments and when ammonification from soil N was optimal. Animal amendments were added yearly in annual systems (31.0 ± 2.91) vs every three years in the ley pasture (12.9 ± 2.91) resulting in a management effect. Copy numbers of AOB (2.69 x 108 ± 4.94 x 107) were greatest in plots receiving compost vs chicken manure. Preliminary measurements of AOA gene copy numbers reveal a similar trend to that of AOB. But, gene copy numbers of AOA (105 to 106) were lower than those of AOB. Nitrification potentials were not different across treatments in September, 11.8 ± 2.28. This research will contribute to the development of novel cropping systems and land-use managements that maintain and promote efficient N cycling.

  14. TALL FESCUE AND ASSOCIATED MUTUALISTIC TOXIC FUNGAL ENDOPHYTES IN AGROECOSYSTEMS

    Science.gov (United States)

    Bacon et al. (1977) proposed and Hoveland et al. (1980, 1986) substantiated that impaired health and performance of livestock grazing tall fescue [Lolium arundinaceum S. J. Darbyshire, formerly Festuca arundinacea Schreb.] were associated with the fungal endophyte Neotyphodium coenophialum Glenn, Ha...

  15. Metagenomics and other Methods for Measuring Antibiotic Resistance in Agroecosystems

    Science.gov (United States)

    Background: There is broad concern regarding antibiotic resistance on farms and in fields, however there is no standard method for defining or measuring antibiotic resistance in environmental samples. Methods: We used metagenomic, culture-based, and molecular methods to characterize the amount, t...

  16. Biodiversity and Seasonal Changes of the Microbiome in Chernozem Agroecosystem

    Science.gov (United States)

    Kutovaya, Olga; Chernov, Timofey; Tkhakakhova, Azida; Ivanova, Ekaterina

    2016-04-01

    Studies of the influence of different agricultural technologies on the soil microbiome are widespread; they are important for understanding the dependence of the microbiome on environmental and soil factors and solution of practical problems related to the control of biochemical processes in soils used in agriculture. The seasonal variability (spring-summer-autumn) of the taxonomic structure of prokaryotic microbiomes in chernozems was studied using sequencing of the 16S rRNA gene. The DNA preparation was used as the matrix for a polymerase chain reaction with the use of a pair of universal primers to the variable region V4 of the 16S rRNA gene - F515 (GTGCCAGCMGCCGCGGTAA) and R806 (GGACTACVSGGGTATCTAAT). The preparation of the samples and sequencing were made on a GS Junior. The samples were collected from the topsoil (0-20 cm) horizons of a long-term fallow and croplands differing in the rates of application of mineral fertilizers (NPK). The results of the weighted UniFrac analysis show that the microbiomes of the fallow and field were distinctly distinguished and that the type of land use significantly affected the structure of the microbial community. The most sensitive to the type of land use were the representatives of the Firmicutes, Gemmatiomonades, and Verrucomicrobia phyla. The type of vegetation and aeration of the root-dwelling soil layer seem to be key factors of this influence. The microbiomes analyzed also differed by seasons: in the autumn samples, they were closer to the spring ones than to the summer ones. This fact evidences that the seasonal differences in the microbiomes are not simple gradual temporal changes; they reflect the influence of some ecological factors transforming the phylogenetic structure of prokaryotic communities. As the seasonal shift was equally expressed in the microbiomes of the field and fallow, it is logical to assume that it was caused by the factors common for two systems of land use. Statistically sensitive to seasonal environmental changes were representatives of the Taumarchaeota, Acidobacteria, Bacteroides, Firmicutes, and Verrucomicrobia groups. The differences in the structure of the soil prokaryotic communities were more significant between seasons than those related to different systems of land use. It is noteworthy that the UniFrac analysis did not practically reveal differences in the prokaryotic communities between the fertilized and unfertilized arable soils, since it was difficult to distinguish them from the differences related to the natural heterogeneity of the soil samples (replicates) analyzed. It is probably related to the high buffer capacity and the high adaptive potential of chernozems. In this experiment, even taking into account the 30-year history, the application of fertilizers is a less significant factor affecting the structure of the microbiome than the type of land use or seasonal climate changes. The phylogenetic diversity estimated by the Shannon index, the number of the operating taxonomic units found, and the Chao1 index little depends on the rate of the fertilizers applied and the type of land use; however, one can mention a rather higher diversity of the microbiomes in the summer and autumn periods compared to the spring one.

  17. Glomalin as an indicator of mycorrhizae in tropical agroecosystems

    Science.gov (United States)

    Arbuscular mycorrhizae (AM) are symbiotic mutualistic associations established between the roots of most plants and certain soil fungi. This symbiosis has positive effects on the development and nutrition of plants as it provides them with low mobility soil elements such as P, Zn and Cu. It also imp...

  18. Risk identification of agricultural drought for sustainable Agroecosystems

    Science.gov (United States)

    Dalezios, N. R.; Blanta, A.; Spyropoulos, N. V.; Tarquis, A. M.

    2014-09-01

    Drought is considered as one of the major natural hazards with a significant impact on agriculture, environment, society and economy. Droughts affect sustainability of agriculture and may result in environmental degradation of a region, which is one of the factors contributing to the vulnerability of agriculture. This paper addresses agrometeorological or agricultural drought within the risk management framework. Risk management consists of risk assessment, as well as a feedback on the adopted risk reduction measures. And risk assessment comprises three distinct steps, namely risk identification, risk estimation and risk evaluation. This paper deals with risk identification of agricultural drought, which involves drought quantification and monitoring, as well as statistical inference. For the quantitative assessment of agricultural drought, as well as the computation of spatiotemporal features, one of the most reliable and widely used indices is applied, namely the vegetation health index (VHI). The computation of VHI is based on satellite data of temperature and the normalized difference vegetation index (NDVI). The spatiotemporal features of drought, which are extracted from VHI, are areal extent, onset and end time, duration and severity. In this paper, a 20-year (1981-2001) time series of the National Oceanic and Atmospheric Administration/advanced very high resolution radiometer (NOAA/AVHRR) satellite data is used, where monthly images of VHI are extracted. Application is implemented in Thessaly, which is the major agricultural drought-prone region of Greece, characterized by vulnerable agriculture. The results show that agricultural drought appears every year during the warm season in the region. The severity of drought is increasing from mild to extreme throughout the warm season, with peaks appearing in the summer. Similarly, the areal extent of drought is also increasing during the warm season, whereas the number of extreme drought pixels is much less than those of mild to moderate drought throughout the warm season. Finally, the areas with diachronic drought persistence can be located. Drought early warning is developed using empirical functional relationships of severity and areal extent. In particular, two second-order polynomials are fitted, one for low and the other for high severity drought classes, respectively. The two fitted curves offer a forecasting tool on a monthly basis from May to October. The results of this drought risk identification effort are considered quite satisfactory offering a prognostic potential. The adopted remote-sensing data and methods have proven very effective in delineating spatial variability and features in drought quantification and monitoring.

  19. Risk identification of agricultural drought for sustainable agroecosystems

    Directory of Open Access Journals (Sweden)

    N. R. Dalezios

    2014-04-01

    Full Text Available Drought is considered as one of the major natural hazards with significant impact to agriculture, environment, society and economy. Droughts affect sustainability of agriculture and may result in environmental degradation of a region, which is one of the factors contributing to the vulnerability of agriculture. This paper addresses agrometeorological or agricultural drought within the risk management framework. Risk management consists of risk assessment, as well as a feedback on the adopted risk reduction measures. And risk assessment comprises three distinct steps, namely risk identification, risk estimation and risk evaluation. This paper deals with risk identification of agricultural drought, which involves drought quantification and monitoring, as well as statistical inference. For the quantitative assessment of agricultural drought, as well as the computation of spatiotemporal features, one of the most reliable and widely used indices is applied, namely the Vegetation Health Index (VHI. The computation of VHI is based on satellite data of temperature and the Normalized Difference Vegetation Index (NDVI. The spatiotemporal features of drought, which are extracted from VHI are: areal extent, onset and end time, duration and severity. In this paper, a 20 year (1981–2001 time series of NOAA/AVHRR satellite data is used, where monthly images of VHI are extracted. Application is implemented in Thessaly, which is the major agricultural drought-prone region of Greece, characterized by vulnerable agriculture. The results show that agricultural drought appears every year during the warm season in the region. The severity of drought is increasing from mild to extreme throughout the warm season with peaks appearing in the summer. Similarly, the areal extent of drought is also increasing during the warm season, whereas the number of extreme drought pixels is much less than those of mild to moderate drought throughout the warm season. Finally, the areas with diachronic drought persistence can be located. Drought early warning is developed using empirical functional relationships of severity and areal extent. In particular, two second-order polynomials are fitted, one for low and the other for high severity drought classes, respectively. The two fitted curves offer a forecasting tool on a monthly basis from May to October. The results of this drought risk identification effort are considered quite satisfactory offering a prognostic potential. The adopted remote sensing data and methods have proven very effective in delineating spatial variability and features in drought quantification and monitoring.

  20. Estimation of Nitrogen Fertilizer Use Efficiency in Dryland Agroecosystem

    Institute of Scientific and Technical Information of China (English)

    LI Shi-qing; LI Sheng-xiu

    2001-01-01

    A field trial was carried out to study the nitrogen fertilizer recovery by four crops in succession in manurial loess soil in Yangling. The results showed that the nitrogen fertilizer not only had the significant effects on the first crop , but also had longer residual effects, even on the fourth crop. The average apparent nitrogen fertilizer recovery by the first crop was 31.7%, and the accumulative nitrogen recovery by the 4 crops was high as 62.3%, and the latter was double as the former. It is quite clear that the nitrogen fertilizer recovery by the first crop was not reliable for estimating the nitrogen fertilizer unless the residual effect of nitrogen fertilizer was included.

  1. Carbon emissions and sinks in agro-ecosystems of China

    Institute of Scientific and Technical Information of China (English)

    林而达; 李月娥; 郭李萍

    2002-01-01

    Besides ruminant animals and their wastes, soil is an important regula ting medium in carbon cycling. The soil can be both a contributor to climate cha nge and a recipient of impacts. In the past, land cultivation has generally resu lted in considerable depletion of soil organic matter and the release of greenho use gases (GHGs) into the atmosphere. The observation in the North-South Transec t of Eastern China showed that climate change and land use strongly impact all s oil processes and GHG exchanges between the soil and the atmosphere. Soil manage ment can restore organic carbon by enhancing soil structure and fertility and by doing so mitigating the negative impacts of atmospheric greenhouses on climate. A wide estimation carried out in China shows that carbon sequestration potentia l is about 77.2 MMt C/a (ranging from 26.1—128.3 MMt C/a) using proposed IPCC a ctivities during the next fifty years.

  2. Integration of wastewater treatment in agro-ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Geber, Ulrika [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Ecology and Crop Production Science

    2000-07-01

    There is a need to find more ecologically sustainable wastewater treatment systems where increased reuse of phosphorus and nitrogen is combined with efficient resource use and decreased eutrophication of recipients. This thesis concerns the ecological sustainability in systems for treatment of municipal wastewater where processes at the WWTP are substituted for ecosystem services. A crop irrigation system was chosen for a study of how natural treatment of pre-treated municipal wastewater could be integrated with agricultural production. Reuse efficiency of nutrients and suitability as substrate for biogas generation was studied in reed canary grass (Phalaris arundinacea L.), meadow foxtail (Alopecurus pratensis L.) and smooth bromegrass (Bromus inermis Leyss.) irrigated with pre-treated wastewater. Crop management in order to increase potential biomass quality for biogas generation was studied in reed canary grass. Resource use in treatment systems differing in their demand of land area and purchased input was evaluated in an emergy analysis. There were only small differences between species in N and P removal and in the yield of dry matter and digestible organic matter. The reed canary grass and meadow foxtail can function well as catch crops in wastewater treatment and potentially as substrates for biogas production. The risk of N leaching in the harvested reed canary grass ley, receiving 175 to 350 kg N ha{sup -1} applied as 300 to 700 mm wastewater, is considered low due to an observed low content soil water NO{sub 3}{sup -}N during the vegetation period and of soil NO{sub 3}{sup -}N in autumn. Increased cutting frequency did not increase the yield of digestible organic matter in reed canary grass. Increased stubble height could not compensate for the effects of increased harvest frequency on the yield of dry matter and digestible organic matter. The emergy analysis did not reveal any differences in the use of purchased inputs between treatment systems. A high demand of land area as in wetland treatment did not reduce the demand of purchased inputs. In terms of emergy the wastewater irrigation of grass leys for nutrient reuse and as substrate for biogas generation, was not found to be resource effective.

  3. Challenges of reducing excess nitrogen in Japanese agroecosystems.

    Science.gov (United States)

    Yagi, Kazuyuki; Minami, Katsuyuki

    2005-09-01

    Fertilizer N use in Japan has decreased by about 30% from 1960 to 2000, while keeping a little increase in cereal yields. This has resulted in a significant increase in apparent nitrogen use efficiency, in particular for rice. On the other hand, national N load on the environment associated with the production and consumption of domestic and imported agricultural products has almost tripled during this period, mainly due to the dramatic increase of imports of food and feedstuffs. The environmental problems, including water and air pollution, caused by the excessive loads of N are serious public concerns and there is an urgent need to minimize N losses from agricultural production. In order to meet the necessity for reducing the environmental impacts by excess N, political and technological measures have been taken at regional and country levels. In recent years, the Japanese government has embarked on a series of policies to encourage transition to an environmentally conscious agriculture. Promoting proper material circulation with reducing fertilizer impact and utilizing biomass and livestock wastes is emphasized in these policies. The effectiveness of environmental assessment and planning for reducing regional and national N load has been discussed. Implementation of environmentally friendly technologies and management, both conventional and innovational, have been developed and adopted in Japanese agriculture. The effectiveness of conventional technologies in reducing environmental reactive N has been re-evaluated. Innovative technologies, such as use of controlled availability fertilizers and livestock wastes compost pellets, are being investigated and extended. A comprehensive approach that applies political and technological measures with closer co-operation is necessary to control reactive N in the environment.

  4. Emergy Analysis of Agro-ecosystem in Poyang Lake Area

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    By using emergy analysis theory and methods, we conduct quantitative analysis on the input and output of emergy, and sustainable development of agro-ecological system in Poyang Lake Area. The results show that compared with the national average, the environmental loading ratio is relatively low in this area; the net emergy yield rate is high; the sustainable development ability is strong. Finally according to the results of emergy analysis, corresponding countermeasures are put forward as follows: develop agriculture based on the existing rich natural resources; increase technological inputs; develop circular agriculture; promote sustainable agricultural development.

  5. Potentials and Prospects of Sorghum Allelopathy in Agroecosystems

    Science.gov (United States)

    The promising allelopathic potential of sorghum [Sorghum bicolor L. (Moench)] opens a fruitful area of research to exploit this phenomenon in weed control and regulation of nutrient cycle. The data suggests that sorghum allelopathy can be exploited in different cropping practices such as cover crop,...

  6. Challenges of reducing excess nitrogen in Japanese agroecosystems

    Institute of Scientific and Technical Information of China (English)

    Kazuyuki YAGI; Katsuyuki MINAMI

    2005-01-01

    Fertilizer N use in Japan has decreased by about 30% from 1960 to 2000, while keeping a little increase in cereal yields. This has resulted in a significant increase in apparent nitrogen use efficiency, in particular for rice. On the other hand, national N Icad on the environment associated with the production and consumption of domestic and imported agricultural products has almost tripled during this period, mainly due to the dramatic increase of imports of food and feedstuffs. The environmental problems, including water and air pollution, caused by the excessive loads of N are serious public concerns and there is an urgent need to minimize N losses from agricultural production. In order to meet the necessity for reducing the environmental impacts by excess N, political and technological measures have been taken at regional and country levels. In recent years, the Japanese government has embarked on a series of policies to encourage transition to an environmentally conscious agriculture. Promoting proper material circulation with reducing fertilizer impact and utilizing biomass and livestock wastes is emphasized in these policies. The effectiveness of environmental assessment and planning for reducing regional and national N Icad has been discussed. Implementation of environmentally friendly technologies and management, both conventional and innovational, have been developed and adopted in Japanese agriculture. The effectiveness of conventional technologies in reducing environmental reactive N has been re-evaluated. Innovative technologies, such as use of controlled availability fertilizers and livestock wastes compost pellets, are being investigated and extended.A comprehensive approach that applies political and technological measures with closer cooperation is necessary to control reactive N in the environment.

  7. Sustainable management of heavy metals in agro-ecosystems.

    NARCIS (Netherlands)

    Moolenaar, S.W.

    1998-01-01

    In 1993, the Netherlands Organization for Scientific Research (NWO) launched a priority research program on 'Sustainability and Environmental Quality'. Within this program, the METALS subprogram focusses on the accumulation of metals in economy (e.g., zinc in gutters) and the environment (e.g., soil

  8. Soil Health Management under Hill Agroecosystem of North East India

    Directory of Open Access Journals (Sweden)

    R. Saha

    2012-01-01

    Full Text Available The deterioration of soil quality/health is the combined result of soil fertility, biological degradation (decline of organic matter, biomass C, decrease in activity and diversity of soil fauna, increase in erodibility, acidity, and salinity, and exposure of compact subsoil of poor physicochemical properties. Northeast India is characterized by high soil acidity/Al+3 toxicity, heavy soil, and carbon loss, severe water scarcity during most parts of year though it is known as high rainfall area. The extent of soil and nutrient transfer, causing environmental degradation in North eastern India, has been estimated to be about 601 million tones of soil, and 685.8, 99.8, 511.1, 22.6, 14.0, 57.1, and 43.0 thousand tones of N, P, K, Mn, Zn, Ca, and Mg, respectively. Excessive deforestation coupled with shifting cultivation practices have resulted in tremendous soil loss (200 t/ha/yr, poor soil physical health in this region. Studies on soil erodibility characteristics under various land use systems in Northeastern Hill (NEH Region depicted that shifting cultivation had the highest erosion ratio (12.46 and soil loss (30.2–170.2 t/ha/yr, followed by conventional agriculture system (10.42 and 5.10–68.20 t/ha/yr, resp.. The challenge before us is to maintain equilibrium between resources and their use to have a stable ecosystem. Agroforestry systems like agri-horti-silvi-pastoral system performed better over shifting cultivation in terms of improvement in soil organic carbon; SOC (44.8%, mean weight diameter; MWD (29.4%, dispersion ratio (52.9%, soil loss (99.3%, soil erosion ratio (45.9%, and in-situ soil moisture conservation (20.6% under the high rainfall, moderate to steep slopes, and shallow soil depth conditions. Multipurpose trees (MPTs also played an important role on soil rejuvenation. Michelia oblonga is reported to be a better choice as bioameliorant for these soils as continuous leaf litter and root exudates improved soil physical behaviour and SOC considerably. Considering the present level of resource degradation, some resource conservation techniques like zero tillage/minimum tillage, hedge crop, mulching, cover crop need due attention for building up of organic matter status for sustaining soil health.

  9. Sustainable management of heavy metals in agro-ecosystems.

    OpenAIRE

    1998-01-01

    In 1993, the Netherlands Organization for Scientific Research (NWO) launched a priority research program on 'Sustainability and Environmental Quality'. Within this program, the METALS subprogram focusses on the accumulation of metals in economy (e.g., zinc in gutters) and the environment (e.g., soil), the mechanisms behind these processes, the associated risks, the possibilities for a sustainable management of metal flows, and their consequences for society and environment. This Ph.D. thesis ...

  10. Emergy Analysis of Agro-ecosystem of Resource-based City in Vulnerable Eco-regions——A Case of Yulin City%生态脆弱区资源型城市农业生态系统的能值分析——以榆林市为例

    Institute of Scientific and Technical Information of China (English)

    李俊莉; 曹明明

    2012-01-01

    [Objective] The development state and major sustainable development obstacle of ago-ecosystem about resource-based city in vulnerable eco-regions were studied. [ Method] The input and output state and comprehensive development level of ago-ecosystem in Yulin city, from 2000 to 2008 were analyzed by using the method of emergy analysis. [Result] The results of emergy input and output showed that the main emergy input of agro-ecosystem of Yulin city was unpaid emergy. The industrial assistant emergy of the total emergy input ratio in 2008 was only 1/4 of the national average, while the labor emergy accounted for up to 68% of renewable organic emergy; the ago-ecosystem of Yulin city was still in the stage of traditional agriculture and depended on manpower and environmental resources. The results of comprehensive evaluation showed that the development potential in Yulin City is high and it has strong sustainable ability of ago-ecosystem. The development state of the natural ago-ecosystem is relatively superior. The development state of the economic ago-ecosystem is low, but the development potential is great. The development state of the social ago-ecosystem was improved, but the production efficiency of rural labor was low. In 2008, the production superiority degree index was 0.71 and the competitive industry (livestock) was obvious; the system stability degree index was only 0.49 and the stability of itself needs to be enhanced; the emergy sustainability index was 2.76 and the ago-ecosystem was a dynamic system. [Conclusion] Some measures should be taken to make the ago-ecosystem input and output emergy to a higher level and make the traditional extensive mode to modern scientific technology, highly intensive and high efficiency, such as improving renewable resources use efficiency, optimizing system structure, increasing the investment of agricultural science and technology assistant emergy.%[目的]研究生态脆弱区资源型城市农业生态系统的发展现

  11. 灌溉对农田温室效应贡献及土壤碳储量影响研究进展%Advances in Research on the Effects of Irrigation on the Greenhouse Gases Emission and Soil Carbon Sequestration in Agro-ecosystem

    Institute of Scientific and Technical Information of China (English)

    齐玉春; 郭树芳; 董云社; 彭琴; 贾军强; 曹丛丛; 孙良杰; 闫钟清; 贺云龙

    2014-01-01

    countries and regions. Water management is one of the important measures that mitigate the emissions of nitrous oxide (N2O) and methane (CH4). Both the emission amount and the emission pathway of N2O and CH4are significantly affected by the soil water condition. There usually exists marked trade-off relationship between CH4 effluxes and N2O effluxes when soil moisture changes, so the comprehensive evaluation indicators such as global warming potentials (GWPs) are more conducive to reflect the actual change in greenhouse effect contribution of agricultural soil exactly. There exist various possibilities in the effect of irrigation on soil organic C (SOC) pool, such as increase, decrease, or no significant changes, and the responses of SOC to irrigation also vary a lot under different climate and soil conditions. In general, the stimulated effects of irrigation on SOC are more significant in relatively dry regions than in humid regions. Meanwhile, SOC in different forms often shows different response sensitivities and variation trends to irrigation. The effect evaluation of irrigation measures should be considered from the multiple perspectives of water-saving, increasing SOC pool and enhancing the utilization efficiency of liable organic C. To sum up, there still exists large uncertainties in the effects of irrigation on soil greenhouse gas emission and SOC in agro-ecosystem up to now. The future study should be focused on following contents: (1) to strengthen the comparison study of different irrigation patterns, especially the study on the spatial differences of greenhouse gases emission under different irrigation patterns; (2) to pay more attention to the comprehensive effect of different greenhouse gases and the ecosystem carbon budget; (3) to developin-situ field research for both long period and short period; (4) to probe into the microbiology driving mechanism of irrigation on farmland greenhouse effect and soil C sequestration.%农田碳库是全球碳库最活跃

  12. Ecological complexity in a coffee agroecosystem: spatial heterogeneity, population persistence and biological control.

    Directory of Open Access Journals (Sweden)

    Heidi Liere

    Full Text Available BACKGROUND: Spatial heterogeneity is essential for the persistence of many inherently unstable systems such as predator-prey and parasitoid-host interactions. Since biological interactions themselves can create heterogeneity in space, the heterogeneity necessary for the persistence of an unstable system could be the result of local interactions involving elements of the unstable system itself. METHODOLOGY/PRINCIPAL FINDINGS: Here we report on a predatory ladybird beetle whose natural history suggests that the beetle requires the patchy distribution of the mutualism between its prey, the green coffee scale, and the arboreal ant, Azteca instabilis. Based on known ecological interactions and the natural history of the system, we constructed a spatially-explicit model and showed that the clustered spatial pattern of ant nests facilitates the persistence of the beetle populations. Furthermore, we show that the dynamics of the beetle consuming the scale insects can cause the clustered distribution of the mutualistic ants in the first place. CONCLUSIONS/SIGNIFICANCE: From a theoretical point of view, our model represents a novel situation in which a predator indirectly causes a spatial pattern of an organism other than its prey, and in doing so facilitates its own persistence. From a practical point of view, it is noteworthy that one of the elements in the system is a persistent pest of coffee, an important world commodity. This pest, we argue, is kept within limits of control through a complex web of ecological interactions that involves the emergent spatial pattern.

  13. Phosphorus in agroecosystems on gray forest soils in the opolie regions of Central Russia

    Science.gov (United States)

    Nikitishen, V. I.; Lichko, V. I.; Kurganova, E. V.

    2008-08-01

    Long-term stationary field experiments revealed a poor supply of gray forest soils with available phosphorus, which provides no more than half the amount necessary for optimum nutrition of plants. It was found that agricultural crops with different capacities to assimilate phosphates from the soil and fertilizers have strong requirements for phosphorus fertilizers and abruptly increase their utilization in the production process with increasing level of nitrogen nutrition. Crops with the optimum level of nitrogen nutrition uptake a double amount of phosphorus compared to crops depleted in nitrogen. Clover and barley have an increased capacity to mobilize soil phosphates from the lower horizons at an extremely low content of available forms of them in the plow layer. Winter wheat and corn are characterized by an active uptake of phosphorus applied with fertilizer and its efficient utilization in the production process if the nitrogen supply is not a limiting factor. The level of phosphorus nutrition of subsequent rotation crops increases due to the enrichment of the root-inhabited soil layer with phosphorus from clover root and harvest residues. Based on the data about the unacceptably abrupt decrease in the application of mineral fertilizers in Russian agriculture (90% of fertilizers are exported now), it is shown that the export of fertilizers should be limited at the state level, because chemicals, and primarily phosphorus fertilizers, should be considered strategic resources for internal use only.

  14. HUMAN IMPACT ASSESSMENT ON THE SICILIAN AGROECOSYSTEMS THROUGH THE EVALUATION OF MELLIFEROUS AREAS

    Directory of Open Access Journals (Sweden)

    G. Ferrauto

    2013-04-01

    Full Text Available Human activity has influenced and profoundly changed the territory of Sicily. The increase of urban and suburban areas, transport infrastructure and the changes in land cover use, have led to a fragmentation of the landscape and consequently, of areas of nectariferous importance. Honey is one of the products most tied to and influenced by the land composition since it derives its main features from the environment, vegetation and flora of the areas in which the bees move. The goal of this work is to built a map of the melliferous areas present in Sicily and then to chart and assess the state of fragmentation and disturbance of areas of apiarian interest, caused by the presence of urban infrastructure and road networks, so as to better define future planning guidelines for the protection and management of the environment for the preservation of honeybees and of beekeeping activities.

  15. Cover crop effects on soil microbial communities and enzyme activity in semiarid agroecosystems

    Science.gov (United States)

    The objective of this study was to compare a fallow-winter wheat (Triticum aestivum L.) rotation to several cover crop-winter wheat rotations under dryland and irrigated conditions in the semiarid US High Plains. We carried out a study that included two sites (Sidney, NE, and Akron, CO), and three s...

  16. Entomopathogenic fungi Metarhizium spp. in the soil environment of an agroecosystem

    DEFF Research Database (Denmark)

    Steinwender, Bernhardt Michael

    Species of the entomopathogenic fungal genus Metarhizium are found worldwide predominantly in the soil environment where they infect a broad spectrum of insects, but also associate with plant roots. To increase performance of Metarhizium as biological control agents against pests, fundamental...

  17. Analysis of biological qualities of land in traditional and conventional agro-ecosystems

    Directory of Open Access Journals (Sweden)

    Eugen Skura

    2013-12-01

    Full Text Available Land constitutes the most important natural resource from the perspective of environmental and human life, for many ecological functions and socio-economical performs. The provision of continuous recycling of nutrients for plants, water retention, storage of carbon reserves, filtering many potential pollutant substances, are some of the key ecological functions of soil. Production of biomass, the supply of food for man and animals, production of fibers for industry, the plant for agro-industrial use of those medical, constitute social functions - economic land which affect the welfare of everyday human life. These important ecological and economic functions not depend only on land use, but also its qualities, and in particular the biological qualities. Biological qualities of the land, which determine the level of fertility, primarily depend on management practices of agricultural systems. In conventional systems of agriculture, unlike traditional systems, soil fertility is really threatened, due to the accumulation of pollutant substances used and their impact on soil micro-flora. Protecting biological qualities of land remains a perennial target of agricultural systems more to ensure its functioning for a long period of time, to support life on earth.

  18. Analysis and classification of data sets for calibration and validation of agro-ecosystem models

    DEFF Research Database (Denmark)

    Kersebaum, K C; Boote, K J; Jorgenson, J S;

    2015-01-01

    to their relevance for modelling and possible uncertainties. Examples are given for data sets of the different classes. The framework helps to assemble high quality data bases, to select data from data bases according to modellers requirements and gives guidelines to experimentalists for experimental design...

  19. Plasma retinoids concentration in Leptodactylus chaquensis (Amphibia: Leptodactylidae) from rice agroecosystems, Santa Fe province, Argentina.

    Science.gov (United States)

    Teglia, Carla M; Attademo, Andrés M; Peltzer, Paola M; Goicoechea, Héctor C; Lajmanovich, Rafael C

    2015-09-01

    Retinoids are known to regulate important processes such as differentiation, development, and embryogenesis of vertebrates: Alteration in endogenous retinoids concentration is linked with teratogenic effects. Retinol (ROH), retinoid acid (RA), and isoform 13-Cis-retinoic acid (13-Cis-RA), in plasma of a native adults frog, Leptodactylus chaquensis from a rice field (RF) and a forest (reference site; RS) were measured. ROH did not vary between treatment sites. RA and 13-Cis-RA activities were higher (93.7±8.6 μg mL(-1) and 131.7±11.4 μg mL(-1), respectively) in individuals collected from RF than in those from RS (65.5±8.6 μg mL(-1) and 92.2±10.2 μg mL(-1), respectively). The ratios retinoic acid-retinol (RA/ROH) and 13-Cis-RA/ROH revealed significantly higher values in RF than in RS. RA and 13-Cis-RA concentrations in plasma on wild amphibian's species such as L. chaquensis would be suitable biomarkers of pesticide exposure in field monitoring. Finally, the mechanism of alteration in retinoid metabolites alteration should be further explored both in larvae and adult, considering that the potential exposition and uptake contaminants vary between the double lives of these vertebrates.

  20. Nitrogen cycle model of agroecosystem in the karst region of Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    CHEN Ye; LIAN Bin

    2010-01-01

    According to the transport theory of soil solutes and the conditions of soil, geology and climate in the karst region of Guizhou Province, a numerical simulation model of edaphic nitrogen element transport under field conditions is initially established. In this model, NO-3 and NH+4 are regarded as soil solutes. Transformation mechanisms such as biological release, bio-immobilization, ammonium adsorption-desorption, nitration-denitrification and factors of crop root uptaking are considered in this model. It is hoped that the data from this model could directly be used to guide agricultural production in this region and offer feasible ways to improve the use of nitrogen element, sustainable development of agriculture in karst mountainous areas and natural environment.

  1. Impact of Cover Cropping and Landscape Positions on Nitrous Oxide Emissions in Northeastern Agroecosystems

    Science.gov (United States)

    Han, Z.; Walter, M. T.; Drinkwater, L. E.

    2015-12-01

    Studies investigating agricultural nitrous oxide (N2O) emissions tend to rely on plot-scale experiments. However, to understand the impacts of agricultural practices at a larger scale, it is essential to consider the variability of landscape characteristics along with management treatments. This study compared N2O emissions from a fertilizer-based, conventionally managed farm and an organically managed farm that uses legume cover crops as a primary nutrient source. The objective of the study was to assess how management regimes and slope positions interact to impact N2O emissions and soil characteristics. The field experiment was conducted in two adjacent grain farms in upstate New York that both have been under consistent management for 20 years. In the organic farm, red clover was frost-seeded into a winter grain (spelt), and then incorporated in the spring as a nutrient source for the subsequent corn plants. In contrast, the conventionally managed farm used inorganic fertilizer as the nutrient source. Gas measurement was conducted at two landscape positions at both farms: 1) shoulder and 2) toeslope positions. Comparable N2O emissions were found in the clover-corn phase in the organic site and the bare fallow-corn phase in the conventional site. The spelt-corn phase in the organic farm had the lowest N2O emissions. Soil nitrate concentration was the best predictor for seasonal average N2O emissions. The impact of landscape position on N2O emissions was only found in the conventional site, which was driven by higher denitrfication at toeslopes. In the organic farm, such effect was confounded by higher clover biomass at shoulder slopes. Our study shows that the impact of landscape characteristics on N2O emissions could differ across sites based on the complex interplay between environmental conditions and management.

  2. Complex agro-ecosystems for food security in a changing climate

    NARCIS (Netherlands)

    Khumairoh, U.; Groot, J.C.J.; Lantinga, E.A.

    2012-01-01

    Attempts to increase food crop yields by intensifying agricultural systems using high inputs of nonrenewable resources and chemicals frequently lead to de-gradation of natural resources, whereas most technological innovations are not accessible for smallholders that represent the majority of farmers

  3. [Effect of biopreparations on dynamics of the number of bacteria and phytopathogenic fungi in potato agroecosystem].

    Science.gov (United States)

    Patyka, N V; Borodaĭ, V V; Zhitkevich, N V; Khomenko, E V; Gnatiuk, T T; Koltunov, V A; Patyka, V F

    2012-01-01

    Application of biological preparations such as Phytotsid and Planryz favoures the growth of the general number of soil's bacteria population compared with control by 13.0-36.1% in the variant of potato variety Scarbnytsya and by 4.5-24.6% of potato variety Oberig. It also decreases 1.2-1.8 times the number of soil phytopathogens--Fusarium and Alternaria. During the application of Rovral Akvaflo the Shenon's ecological index of species biodiversity was lower than during the bioprepation application. One could observe a decrease of species biodiversity and dominance of dark pigmentation in fungi--Alternaria sp., Cladosporium sp., Phoma sp., Doratomyces sp., and pigmented bacteria.

  4. Potential impact of climatic changes on floristic evolution of phytocoenoses in mediterranean agroecosystems

    Directory of Open Access Journals (Sweden)

    Stefano Benvenuti

    2011-02-01

    Full Text Available In order to predict the potential agronomic scenarios of the future, the probable involvements of climatic changes on weed dynamics were analyzed. In this perspective the several climatic parameters were examined and overlapped to the biological characteristics of the different species to predict both: weed evolution and the sustainability of the relative management. Thermal and CO2 increasing favour the weed ruderality in terms of seed quantity and velocity of seed set. In addition the increasing of stress factors (thermal, drought, UV-B, etc. favour the de-specialization trend as typically occurs in the most persistent weeds. Adverse climatic dynamics, even due to events of opposite biological action (for example drought and flooding, appears to have a synergistic impact with the agronomic disturbances. Indeed these additive disturbances increase the selective pressure of the phytocoenoses and play a crucial role in the allowing survival only to the “segetal” weeds as well it occurs from the origin of agriculture. Consequently, the different degree of resilience induces a decreasing of the phytocoenoses complexity. This biodiversity reduction appears to increase the risk of exotic weed invasion overall regards to species from warmer and more arid environments (potentially even parasite species. Their invasivity could be increased by biotic or abiotic stress factors that are not present in their native environment. The fate of rare weeds appears to go to their extinction, overall if their dynamics is linked to fragile mutualistic interaction as it occurs in the case of entomogamous species. Indeed such simultaneous presence (flora and pollinator fauna is mined by the progressive differences between photoperiod and thermoperiod and the consequent de-synchronization of their phenological phases. This virtual weed evolution through the increasing of the richness of self- and wind-pollinated weeds will involve both: 1 the agricultural landscape degradation; 2 a worse human health because of atmosphere rich of allergenic pollen. In conclusion, weed phytocoenoses appear to be less vulnerable of the relative crops to the climatic injuries. This higher crop vulnerability will increase the pesticides use as well as already predicted regards to entomologic and phytopatologic aspects. Finally, an agronomic strategy of the future was hypothized. This is based on the germplasm utilization of the wild types in order to increase the environmental crop plasticity in the predicted climatic scenarios.

  5. Potential impact of climatic changes on floristic evolution of phytocoenoses in mediterranean agroecosystems

    Directory of Open Access Journals (Sweden)

    Stefano Benvenuti

    Full Text Available In order to predict the potential agronomic scenarios of the future, the probable involvements of climatic changes on weed dynamics were analyzed. In this perspective the several climatic parameters were examined and overlapped to the biological characteristics of the different species to predict both: weed evolution and the sustainability of the relative management. Thermal and CO2 increasing favour the weed ruderality in terms of seed quantity and velocity of seed set. In addition the increasing of stress factors (thermal, drought, UV-B, etc. favour the de-specialization trend as typically occurs in the most persistent weeds. Adverse climatic dynamics, even due to events of opposite biological action (for example drought and flooding, appears to have a synergistic impact with the agronomic disturbances. Indeed these additive disturbances increase the selective pressure of the phytocoenoses and play a crucial role in the allowing survival only to the “segetal” weeds as well it occurs from the origin of agriculture. Consequently, the different degree of resilience induces a decreasing of the phytocoenoses complexity. This biodiversity reduction appears to increase the risk of exotic weed invasion overall regards to species from warmer and more arid environments (potentially even parasite species. Their invasivity could be increased by biotic or abiotic stress factors that are not present in their native environment. The fate of rare weeds appears to go to their extinction, overall if their dynamics is linked to fragile mutualistic interaction as it occurs in the case of entomogamous species. Indeed such simultaneous presence (flora and pollinator fauna is mined by the progressive differences between photoperiod and thermoperiod and the consequent de-synchronization of their phenological phases. This virtual weed evolution through the increasing of the richness of self- and wind-pollinated weeds will involve both: 1 the agricultural landscape degradation; 2 a worse human health because of atmosphere rich of allergenic pollen. In conclusion, weed phytocoenoses appear to be less vulnerable of the relative crops to the climatic injuries. This higher crop vulnerability will increase the pesticides use as well as already predicted regards to entomologic and phytopatologic aspects. Finally, an agronomic strategy of the future was hypothized. This is based on the germplasm utilization of the wild types in order to increase the environmental crop plasticity in the predicted climatic scenarios.

  6. Estimating total nitrogen deposition in agroecosystems in northern China during the wheat cropping season

    Institute of Scientific and Technical Information of China (English)

    Christie; PETER; Fangmeier; ANDREAS

    2010-01-01

    Atmospheric nitrogen (N) deposition has been poorly documented in northern China, an intensive agricultural and industrial region with large emissions of NHx and NOy. To quantify N deposition, total airborne N deposition was determined at three agricultural sites using a manual integrated total nitrogen input (ITNI) system during growth of winter wheat (Triticum aestivum L.) and Italian ryegrass (Lolium multiflorum Lam.) from September 2005 to May 2006. Total estimated N deposition averaged 54.9 and 43.2 kg N/hm2 across the three sites when wheat was grown to flowering and maturing, respectively. The average value was 50.2 kg N/hm2 when ryegrass was the indicator plant. Both indicator species gave similar total airborne N input results. The intermediate level of N supplied resulted in the highest N deposition, and the ratio of N acquired from deposition to total N content of the whole system decreased with increasing N supply to the roots. The contribution of atmospheric N to the total N content of the wheat and ryegrass sand culture systems ranged from 10% to 24%.

  7. Deep soil layer is fundamental for evaluating carbon accumulation in agroecosystems

    Science.gov (United States)

    Dal Ferro, Nicola; Morari, Francesco; Simonetti, Gianluca; Polese, Riccardo; Berti, Antonio

    2015-04-01

    Soil organic carbon (SOC) is essential to secure key ecosystem services such as the provision of food and other biomass production, the filtering, buffering and transformation capacity and the climate regulation. It has been estimated that approximately 57% of the globally emitted C (8.7 Gt y-1) to the atmosphere is adsorbed by biospheric C pools, ascertaining the potential soil C sink capacity of managed ecosystems at 55 to 78 Gt, of which only 50 to 66% attainable. Therefore it is essential the full knowledge of soil management practices that can affect SOC dynamics and, in turn, climate change. Several studies focussed on the evaluation of the best cropping management practices to accumulate C in the soil profile. Nevertheless, in most cases soil analyses were made in the topsoil (generally in the 0-30 cm layer), ignoring the effect of C translocation in the deeper soil profile as a result of tillage practices, crop root deepening etc. In this context, in a long-term experiment established in the early 1960s, we quantified the SOC accumulation within the soil profile (0-90 cm) and evaluate the effects of different cropping system on SOC dynamics. The experiment is located at the experimental farm of the University of Padova, in northeastern Italy. The trial compares four rotations with three levels of mineral fertilisation and with or without organic fertilisation. The rotations considered are: continuous crops (grain maize, forage maize, winter wheat and permanent meadow); two-year (maize-wheat); four-year (sugarbeet, soybean, wheat, maize) and six-year (maize, sugarbeet, maize, wheat, alfalfa, alfalfa) with different levels of mineral, organic and mixed fertilisations. Crops with superficially developed rooting systems (e.g. permanent meadow) highly increased SOC only in the topsoil. This effect was enhanced by the contribution of organic amendment-C. Root-derived carbon played a pivotal role also in the deepest soil profile (60-90 cm) by increasing the SOC translocation. Considering the whole profile, the highest C accumulation was observed in cropping systems with high biomass production and deep rooting systems. Results indicated that for estimating the effects of cropping systems and agricultural practices on C accumulation, analyses in the topsoil can be misleading and it is necessary to consider the whole profile.

  8. Antibiotics and antibiotic resistance in agroecosystems: Cultural methods and gaps in knowledge

    Science.gov (United States)

    Varying cultural methodologies are used in assessment of antibiotic resistance in environmental samples. Culture based methods commonly involve isolation of target bacteria on general or selective media, and assessing growth in response to specific concentrations of antibiotics. Though time consumin...

  9. Antibiotic resistance gene concentrations in agroecosystems following beef manure or poultry litter deposition

    Science.gov (United States)

    Antibiotics are commonly used in livestock production to promote growth and combat disease. However, as much as 80% of the drug may pass through the animal and into the soil where selective pressure may favor survival of antibiotic resistant bacteria. Recent studies have shown that there is also a p...

  10. Elucidating the potential for transfer of antibiotic resistance genes trhough agro-ecosystems

    Science.gov (United States)

    Increases in the occurrence of antibiotic resistance (AR) in clinical pathogens raises concerns about how resistance is spread within and between human, environmental and agricultural eco-systems. Livestock manure applied to soil may increase AR bacterial concentrations as a result of addition of ma...

  11. A stochastic empirical model for heavy-metal balnces in Agro-ecosystems

    NARCIS (Netherlands)

    Keller, A.N.; Steiger, von B.; Zee, van der S.E.A.T.M.; Schulin, R.

    2001-01-01

    Mass flux balancing provides essential information for preventive strategies against heavy-metal accumulation in agricultural soils that may result from atmospheric deposition and application of fertilizers and pesticides. In this paper we present the empirical stochastic balance model, PROTERRA-S,

  12. Context-dependency of arbuscular mycorrhizal fungi on plant-insect interactions in an agroecosystem

    Directory of Open Access Journals (Sweden)

    Nicholas A Barber

    2013-09-01

    Full Text Available Plants interact with a variety of other community members that have the potential to indirectly influence each other through a shared host plant. Arbuscular mycorrhizal fungi (AMF are generally considered plant mutualists because of their generally positive effects on plant nutrient status and growth. AMF may also have important indirect effects on plants by altering interactions with other community members. By influencing plant traits, AMF can modify aboveground interactions with both mutualists, such as pollinators, and antagonists, such as herbivores. Because herbivory and pollination can dramatically influence plant fitness, comprehensive assessment of plant-AMF interactions should include these indirect effects. To determine how AMF affect plant-insect interactions, we grew Cucumis sativus (Cucurbitaceae under five AMF inoculum treatments and control. We measured plant growth, floral production, flower size, and foliar nutrient content of half the plants, and transferred the other half to a field setting to measure pollinator and herbivore preference of wild insects. Mycorrhizal treatment had no effect on plant biomass or floral traits but significantly affected leaf nutrients, pollinator behavior, and herbivore attack. Although total pollinator visitation did not vary with AMF treatment, pollinators exhibited taxon-specific responses, with honey bees, bumble bees, and Lepidoptera all responding differently to AMF treatments. Flower number and size were unaffected by treatments, suggesting that differences in pollinator preference were driven by other floral traits. Mycorrhizae influenced leaf K and Na, but these differences in leaf nutrients did not correspond to variation in herbivore attack. Overall, we found that AMF indirectly influence both antagonistic and mutualistic insects, but impacts depend on the identity of both the fungal partner and the interacting insect, underscoring the context dependency of plant-AMF interactions.

  13. Long-term effects of compost and cover crops on soil phosphorus in two California agroecosystems

    Science.gov (United States)

    Inefficient P use in agriculture results in soil P accumulation and losses to surrounding ecosystems, highlighting the need to reduce external inputs and use them more efficiently. Composts reduce the need for mineral fertilizers by recycling P from wastes at the regional scale, whereas cover crops ...

  14. Heavy-metal balances of agro-ecosystems in the Netherlands.

    NARCIS (Netherlands)

    Moolenaar, S.W.; Lexmond, Th.M.

    1998-01-01

    Heavy-metal flows (Cd, Cu, Pb, and Zn) of arable, dairy and mixed farming systems in the Netherlands were studied, and farm-gate and field-scale balances calculated. On the field-scale, static and dynamic balances were distinguished. By determining the characteristic metal flows, it became possible

  15. Soil types will alter the response of arable agroecosystems to future rainfall patterns

    Science.gov (United States)

    Zaller, J. G.; Schwarz, T.; Hall, R.; Ziss, E.; von Hohberg und Buchwald, C.; Hösch, J.; Baumgarten, A.

    2012-04-01

    Regional climate change scenarios for eastern Austria (pannonian region) predict fewer but heavier rains during the vegetation period without substantial changes in the total annual amount of rainfall. While many studies investigated the effects of rainfall patterns on ecosystem properties, very little is known on how different soil types might alter ecosystem responses. In order to test this, we conducted an experiment at the AGES lysimeter station using 18 3 m2 lysimeters where we simultaneously manipulated rainfall patterns according to regional climate scenarios (current vs. prognosticated rain) on the three main soil types of the region (sandy calcaric phaeozem, gleyic phaeozem and calcic chernozem). Lysimeters were cultivated according to good farming practice using crop varieties and crop rotations typically for the region. Here, we present results of the response of field peas (Pisum sativum) on important agricultural parameters. Lysimeters under progn. rain showed lower crop cover than under curr. rain while soil types had no effect. Total aboveground biomass production (comprising crops plus weeds) was significantly lower under progn. rain; sandy calcaric phaeozem showed the lowest plant biomass. Pea yields under progn. rain were substantially lower than under curr. rain; again, yields under sandy soils were lower than under the other two soil types. Root growth was significantly higher in progn. rain than in curr. rain; there was a trend towards less root growth in the gleyic soils. Mycorrhization of roots was not influenced by soil types, however under progn. rain colonization rates were lower than under curr. rain. Weed establishment and growth was increased under progn. rain in gleyic soils but decreased in the other soil types. Weed biomass was not affected by rainfall, however sandy soils had less weed biomass than the other soil types. Abundance of the insect pest pea moth (Cydia nigricana) was almost twice as high under progn. rain than under curr. rain, soil types had only little influence on this pest species. These results show that (i) changes in rainfall patterns predicted for the near future due to human-induced global climate changes will substantially affect crop production and management in the study region, and (ii) the influence of different soil types in altering ecosystem responses should be considered when trying to scale-up experimental results derived at the plot level to the landscape level.

  16. Environmental fate of soil applied neonicotinoid insecticides in an irrigated potato agroecosystem.

    Science.gov (United States)

    Huseth, Anders S; Groves, Russell L

    2014-01-01

    Since 1995, neonicotinoid insecticides have been a critical component of arthropod management in potato, Solanum tuberosum L. Recent detections of neonicotinoids in groundwater have generated questions about the sources of these contaminants and the relative contribution from commodities in U.S. agriculture. Delivery of neonicotinoids to crops typically occurs as a seed or in-furrow treatment to manage early season insect herbivores. Applied in this way, these insecticides become systemically mobile in the plant and provide control of key pest species. An outcome of this project links these soil insecticide application strategies in crop plants with neonicotinoid contamination of water leaching from the application zone. In 2011 and 2012, our objectives were to document the temporal patterns of neonicotinoid leachate below the planting furrow following common insecticide delivery methods in potato. Leaching loss of thiamethoxam from potato was measured using pan lysimeters from three at-plant treatments and one foliar application treatment. Insecticide concentration in leachate was assessed for six consecutive months using liquid chromatography-tandem mass spectrometry. Findings from this study suggest leaching of neonicotinoids from potato may be greater following crop harvest in comparison to other times during the growing season. Furthermore, this study documented recycling of neonicotinoid insecticides from contaminated groundwater back onto the crop via high capacity irrigation wells. These results document interactions between cultivated potato, different neonicotinoid delivery methods, and the potential for subsurface water contamination via leaching.

  17. Environmental covariates of Anopheles arabiensis in a rice agroecosystem in Mwea, Central Kenya.

    Science.gov (United States)

    Mwangangi, Joseph M; Muturi, Ephantus J; Shililu, Josephat I; Muriu, Simon; Jacob, Benjamin; Kabiru, Ephantus W; Mbogo, Charles M; Githure, John I; Novak, Robert J

    2007-12-01

    Water quality of aquatic habitats is an important determinant of female mosquito oviposition and successful larval development. This study examined the influence of environmental covariates on Anopheles arabiensis mosquito abundance in the Mwea Irrigation Scheme, Central Province of Kenya, prior to implementation of a malaria vector control program. Experimental rice plots were used to examine the environmental covariates responsible for regulating abundance and diversity of the aquatic stages of malaria vectors. Mosquito larval sampling and water quality analysis were done weekly from the flooding stage to the rice maturation stage. Sampling for mosquito larvae was conducted using standard dipping technique. During each larval collection, environmental covariates such as pH, temperature, conductivity, salinity, dissolved oxygen, water depth, and rice stage were measured. Anopheles arabiensis larval density was highest between 1 wk before transplanting and 4 wk after transplanting with peaks at weeks 0, 3, and 8. The fluctuation in values of the various environmental covariates showed characteristic patterns in different rice growth phases depending on the changes taking place due to the agronomic practices. Using a backward linear regression model, the factors that were found to be associated with abundance of An. arabiensis larvae at any of the rice growing phases included the following: dissolved oxygen, pH, turbidity, water depth, rice height, number of rice tillers, salinity, conductivity, and temperature. The environmental covariates associated with abundance of An. arabiensis were associated with early vegetative stage of the rice growth. For effective control of developmental stages of mosquito larvae, the application of larvicides should be done at the vegetative stage and the larvicides should persist until the beginning of the reproductive stage of the rice.

  18. Larval habitat dynamics and diversity of Culex mosquitoes in rice agro-ecosystem in Mwea, Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Shililu, Josephat I; Gu, Weidong; Jacob, Benjamin G; Githure, John I; Novak, Robert J

    2007-01-01

    Introduction of irrigation projects in developing nations has often been blamed for aggravating the problem of mosquito-borne diseases by creating ideal larval habitats for vector mosquitoes. However, whereas several studies have demonstrated the relationship between malaria vectors and irrigation, little work has been done on culicine mosquitoes despite their potential in transmission of filariasis and arboviruses and their significant biting nuisance in these areas. This study examined the diversity of Culex mosquito fauna and their larval habitats at two sites (Murinduko and Kiamachiri) in Mwea, Kenya over a 12-month period. The habitat types present at each site within a 200-meter radius around the study village, including randomly selected paddies and canals, were sampled every two weeks to examine the relationship between vegetation cover, water depth, turbidity, and Culex larval counts. Ten culicine species belonging to four genera were identified, with 73.1% of the total collection comprising of Culex duttoni and Cx. quinquefasciatus. Other species collected included Cx. annulioris, Cx. poicilipes, Cx. cinereus, Cx. tigripes, Cx. trifilatus, Aedes spp., Coquilettidia fuscopennata, and Ficalbia splendens. Murinduko was more diverse than Kiamachiri in terms of species richness (10 versus 7 species) and larval habitat diversity (11 versus 8 habitat types). Paddies, canals, and rain pools were the most diverse habitats in terms of species richness, and ditches, rock pools, and tree holes were the least diverse. Principal component and correlation analyses showed a strong association between three Culex species and the measured habitat characteristics. Culex poicilipes was strongly associated with floating vegetation, Cx. annulioris with clean water containing emergent vegetation, and Cx. quinquefasciatus was associated with turbid water. Seasonal changes in larval counts in water reservoirs and pool and ditch habitats were closely associated with rainfall. These findings provide important information on larval habitat preference for different Culex species, which will be useful in designing and implementation of larval control operations.

  19. IMPACT OF BT ( BACILLUS THURINGIENSIS ) CROPS ON BAT ACTIVITY IN SOUTH TEXAS AGROECOSYSTEMS

    Science.gov (United States)

    The widespread adoption of transgenic insecticidal crops raises concerns that nontarget species may be harmed and food webs disrupted. The goal of this research is to determine how transgenic Bt (Bacillus thuringiensis) crops impact the activity of Brazilian freetailed bats (Tada...

  20. Building climate resilience into perennial agroecosystems for adaptation to climate change

    Science.gov (United States)

    Adapting to future climate changes will require resilient agricultural systems. Resiliency can be thought of as the ability of an ecosystem to bounce back and persist after a disturbance or shock. Stressors or perturbations may be more severe in the future because of human-induced climate change. On...

  1. THE EFFECT OF SEED TREATMENT ON THE MAIN PATHOGENS PRESENT IN WHEAT AGROECOSYSTEMS.

    Science.gov (United States)

    Stef, R; Grozea, I; Puia, C; Carabet, A; Vlad, M; Manea, D

    2014-01-01

    Wheat crop (Triticum aestivum L.) from Poaceae family is affected by many diseases that cause yield losses. The present paper addresses a topic of economic, agrotechnics and social importance of wheat crop (occupying the first place among the Romanian cultivated crop, feeding 35 to 40% of world population). The study had as main objective product testing like Yunta 246 FS (imidacloprid 233 g/l + tebuconazol 13 g/l), Team Micorriza Plus (Glomus intraradices 150 spore/g + Glomus mosseae 150 spore/g + organic matter 56% and Rhizosphere Bacteria 107 UFC/g) and Condor (Trichoderma spp. 1 x 109 spore/g + Glomus sp. 10 spore/g + Rhizosphere Bacteria 1 x 107 UFC/g and organic matter 7%) applied in the pathosystem wheat/pathogens. The research was conducted in the western part of Romania, in 2010-2012, experience was placed after Latin rectangle method with 10 variants (they are different by product and dose applied) and the data were statistically interpreted. Results showed the presence of pathogens Septoria tritici, Drechslera tritici repentis and Drechslera teres in experimental variants. Statistical analysis showed that the most effective chemical mixture was imidacloprid + tebuconazol at the highest dose tested (3 l/t). Regarding the non-chemical product testing, the product Condor gave positive results. The highest values of quality parameters (protein and gluten) were obtained in the variants treated with Yunta 246 FS.

  2. Quantification of ant manure deposition in a tropical agroecosystem: Implications for host plant nitrogen acquisition

    DEFF Research Database (Denmark)

    Pinkalski, Christian Alexander Stidsen; Damgaard, Christian; Jensen, Karl-Martin Vagn;

    2015-01-01

    Ants are functionally important organisms in most terrestrial ecosystems. Being ubiquitous and abundant, ant communities can affect the availability of resources to both primary and secondary consumers. As nitrogen is a limiting nutrient for plant growth in most terrestrial ecosystems, deposition...

  3. Environmental fate of soil applied neonicotinoid insecticides in an irrigated potato agroecosystem.

    Directory of Open Access Journals (Sweden)

    Anders S Huseth

    Full Text Available Since 1995, neonicotinoid insecticides have been a critical component of arthropod management in potato, Solanum tuberosum L. Recent detections of neonicotinoids in groundwater have generated questions about the sources of these contaminants and the relative contribution from commodities in U.S. agriculture. Delivery of neonicotinoids to crops typically occurs as a seed or in-furrow treatment to manage early season insect herbivores. Applied in this way, these insecticides become systemically mobile in the plant and provide control of key pest species. An outcome of this project links these soil insecticide application strategies in crop plants with neonicotinoid contamination of water leaching from the application zone. In 2011 and 2012, our objectives were to document the temporal patterns of neonicotinoid leachate below the planting furrow following common insecticide delivery methods in potato. Leaching loss of thiamethoxam from potato was measured using pan lysimeters from three at-plant treatments and one foliar application treatment. Insecticide concentration in leachate was assessed for six consecutive months using liquid chromatography-tandem mass spectrometry. Findings from this study suggest leaching of neonicotinoids from potato may be greater following crop harvest in comparison to other times during the growing season. Furthermore, this study documented recycling of neonicotinoid insecticides from contaminated groundwater back onto the crop via high capacity irrigation wells. These results document interactions between cultivated potato, different neonicotinoid delivery methods, and the potential for subsurface water contamination via leaching.

  4. Emergy signature as a basis for sustainability valuation of agro-ecosystems

    DEFF Research Database (Denmark)

    Ghaley, Bhim Bahadur; Montesino San Martin, Manuel; Porter, John Roy

    Traditionally, research and advisory service had focused on increasing crop yield and improving the efficiency of the production systems for bringing down he price of food. However, the environmental and ecological costs are not taken into account which has a significant bearing of the long term...... sustainability of the agricultural practice. The emergy analysis is an accounting tool which takes into account both the environment and the economic costs of the production system, based on principles of thermodynamics. Here the objective of the study is the evaluation of a novel organically based, food...... and energy production (CFE) system to assess the resource use efficiency compared to conventional intensive winter wheat production system in Demark by using Emergy analysis (Odum and Odum, 2000). The emergy analysis was carried out by taking into account the inflow and the outflows of emergy within...

  5. Earthworms, soil aggregates and organic matter decomposition in agro-ecosystems in The Netherlands.

    NARCIS (Netherlands)

    Marinissen, J.C.Y.

    1995-01-01

    The relationships between earthworm populations, soil aggregate stability and soil organic matter dynamics were studied at an experimental farm in The Netherlands.Arable land in general is not favourable for earthworm growth. In the Lovinkhoeve fields under conventional management earthworm populati

  6. Environmental assay on the effect of poultry manure application on soil organisms in agroecosystems.

    Science.gov (United States)

    Delgado, M; Rodríguez, C; Martín, J V; Miralles de Imperial, R; Alonso, F

    2012-02-01

    This paper reports the effects produced on the organisms of the soil (plants, invertebrates and microorganisms), after the application of two types of poultry manure (sawdust and straw bed) on an agricultural land. The test was made using a terrestrial microcosm, Multi-Species Soil System (MS3) developed in INIA. There was no difference in the germination for any of the three species of plants considered in the study. The biomass was increased in the wheat (Triticum aestivum) coming from ground treated with both kinds of poultry manure. Oilseed rape (Brasica rapa) was not affected and regarding vetch (Vicia sativa) only straw poultry manure showed significant difference. For length only Vicia sativa was affected showing a reduction when straw was exposed to poultry manure. When the effect on invertebrates was studied, we observed a reduction in the number of worms during the test, especially from the ground control (13.7%), higher than in the ground with sawdust poultry manure (6.7%), whereas in the ground with straw poultry manure, there was no reduction. The biomass was affected and at the end of the test it was observed that while the reduction of worms in the ground control was about 48%, the number of those that were in the ground with sawdust poultry manure or straw poultry manure decreased by 41% and 22% respectively. Finally, the effects on microorganisms showed that the enzymatic activities: dehydrogenase (DH) and phosphatase and basal respiration rate increased at the beginning of the test, and the differences were statistically significant compared with the values of the control group. During the test, all these parameters decreased (except DH activities) but they were always higher than in the ground control. This is why it is possible to deduce that the contribution of poultry manure caused an improvement in the conditions of fertilization and also for the soil.

  7. Uncertainties in model predictions of nitrogen fluxes from agro-ecosystems in Europe

    Directory of Open Access Journals (Sweden)

    J. Kros

    2012-05-01

    Full Text Available To assess the responses of nitrogen and greenhouse gas emissions to pan-European changes in land cover, land management and climate, an integrated dynamic model, INTEGRATOR, has been developed. This model includes both simple process-based descriptions and empirical relationships, and uses detailed GIS-based environmental and farming data in combination with various downscaling methods. This paper analyses the propagation of uncertainties in model inputs and model parameters to outputs of INTEGRATOR, using a Monte Carlo analysis. Uncertain model inputs and parameters were represented by probability distributions, while spatial correlation in these uncertainties was taken into account by assigning correlation coefficients at various spatial scales. The uncertainty propagation was analysed for the emissions of NH3, N2O and NOx and N leaching to groundwater and N surface runoff to surface water for the entire EU27 and for individual countries. Results show large uncertainties for N leaching and N runoff (relative errors of ~19 % for Europe as a whole, and smaller uncertainties for emission of N2O, NH3 and NOx (relative errors of ~12 %. Uncertainties for Europe as a whole were much smaller compared to uncertainties at Country level, because errors partly cancelled out due to spatial aggregation.

  8. Biodiversity and soil quality in agroecosystems: the use of a qualitative multi-attribute model

    DEFF Research Database (Denmark)

    Cortet, J.; Bohanec, M.; Griffiths, B.

    2009-01-01

    application to the assessment of crop management on soil quality in the case of using conventional and Bt-maize at three field sites in France and Denmark. Our finding was that soil quality was unaffected even though several input attributes were changed. We also analyse the sensitivity of the model...

  9. Measurements of soil carbon dioxide emissions from two maize agroecosystems at harvest under different tillage conditions.

    Science.gov (United States)

    Giacomo, Gerosa; Angelo, Finco; Fabio, Boschetti; Stefano, Brenna; Riccardo, Marzuoli

    2014-01-01

    In this study a comparison of the soil CO2 fluxes emitted from two maize (Zea mays L.) fields with the same soil type was performed. Each field was treated with a different tillage technique: conventional tillage (30 cm depth ploughing) and no-tillage. Measurements were performed in the Po Valley (Italy) from September to October 2012, covering both pre- and postharvesting conditions, by means of two identical systems based on automatic static soil chambers. Main results show that no-tillage technique caused higher CO2 emissions than conventional tillage (on average 2.78 and 0.79 μmol CO2 m(-2) s(-1), resp.). This result is likely due to decomposition of the organic litter left on the ground of the no-tillage site and thus to an increased microbial and invertebrate respiration. On the other hand, fuel consumption of conventional tillage technique is greater than no-tillage consumptions. For these reasons this result cannot be taken as general. More investigations are needed to take into account all the emissions related to the field management cycle.

  10. Establishing a tracer-based sediment budget to preserve wetlands in Mediterranean mountain agroecosystems (NE Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Navas, Ana, E-mail: anavas@eead.csic.es [Department of Soil and Water, Estación Experimental de Aula Dei, EEAD-CSIC, Avda. Montañana 1005, 50059 Zaragoza (Spain); López-Vicente, Manuel, E-mail: mvicente@eead.csic.es [Department of Soil and Water, Estación Experimental de Aula Dei, EEAD-CSIC, Avda. Montañana 1005, 50059 Zaragoza (Spain); Gaspar, Leticia, E-mail: leticia.gaspar@plymouth.ac.uk [School of Geography, Earth and Environmental Science, Plymouth University, Plymouth, Devon PL4 8AA (United Kingdom); Palazón, Leticia, E-mail: lpalazon@eead.csic.es [Department of Soil and Water, Estación Experimental de Aula Dei, EEAD-CSIC, Avda. Montañana 1005, 50059 Zaragoza (Spain); Quijano, Laura, E-mail: lquijano@eead.cisc.es [Department of Soil and Water, Estación Experimental de Aula Dei, EEAD-CSIC, Avda. Montañana 1005, 50059 Zaragoza (Spain)

    2014-10-15

    Mountain wetlands in Mediterranean regions are particularly threatened in agricultural environments due to anthropogenic activity. An integrated study of source-to-sink sediment fluxes was carried out in an agricultural catchment that holds a small permanent lake included in the European NATURA 2000 Network. More than 1000 yrs of human intervention and the variety of land uses pose a substantial challenge when attempting to estimate sediment fluxes which is the first requirement to protect fragile wetlands. To date, there have been few similar studies and those that have been carried out have not addressed such complex terrain. Geostatistical interpolation and GIS tools were used to derive the soil spatial redistribution from point {sup 137}Cs inventories, and to establish the sediment budget in a catchment located in the Southern Pyrenees. The soil redistribution was intense and soil erosion predominated over soil deposition. On the areas that maintained natural vegetation the median soil erosion and deposition rates were moderate, ranging from 2.6 to 6 Mg ha yr{sup −1} and 1.5 to 2.1 Mg ha yr{sup −1}, respectively. However, in cultivated fields both erosion and deposition were significantly higher (ca. 20 Mg ha yr{sup −1}), and the maximum rates were always associated with tillage practices. Farming activities in the last part of the 20th century intensified soil erosion, as evidenced by the 1963 {sup 137}Cs peaks in the lake cores and estimates from the sediment budget indicated a net deposition of 671 Mg yr{sup −1}. Results confirm a siltation risk for the lake and provide a foundation for designing management plans to preserve this threatened wetland. This comprehensive approach provides information useful for understanding processes that influence the patterns and rates of soil transfer and deposition within fragile Mediterranean mountain wetlands subjected to climate and anthropogenic stresses. - Highlights: • Soil erosion threatens long-term sustainability of mountain wetlands and agriculture. • {sup 137}Cs was applied for estimation of soil redistribution in a complex catchment. • A tracer derived sediment budget identified main sources causing lake siltation. • Fallout tracer and GIS provided information useful for wetland preservation. • Vegetation strips around fields would reduce siltation from tillage erosion.

  11. Nutrient flows in urban and peri-urban agroecosystems in three West African cities

    NARCIS (Netherlands)

    Abdulkadir, A.

    2012-01-01

    Key words: Sustainability, CATPCA, two-step cluster analysis, farm types, nutrient balances, West Africa, gross margin, NUTMON/MONQI. Urban and peri-urban agriculture (UPA) is defined as the cultivation of crops and keeping livestock within and around cities. In addition to providing the cities&rsq

  12. Nutrient flows and balances in urban and peri-urban agroecosystems of Kano, Nigeria

    NARCIS (Netherlands)

    Abdulkadir, A.; Leffelaar, P.A.; Agbenin, J.O.; Giller, K.E.

    2013-01-01

    Nutrient balances are useful indicators to assess the sustainability of farming systems. This study study investigates inflow and outflow of major nutrients in urban and periurban production systems in Kano, Nigeria. To this end, 16 households representing three different urban and peri-urban (UPA)

  13. COVER CROPS ENHANCE SOIL ORGANIC MATTER, CARBON DYNAMICS AND MICROBIOLOGICAL FUNCTION IN A MEDITERRANEAN VINEYARD AGROECOSYSTEM

    Science.gov (United States)

    Impacts of soil tillage and cover crops on soil carbon (C) dynamics and microbiological function were investigated in a vineyard grown in California’s Mediterranean climate. We 1) compared soil organic matter (SOM), C dynamics and microbiological activity of two cover crops [Trios 102 (Triticale x T...

  14. FEATURES OF CLIMATE CHANGE ON UKRAINE: SCENARIOS, CONSEQUENCES FOR NATURE AND AGROECOSYSTEMS

    Directory of Open Access Journals (Sweden)

    Svitlana Boychenko

    2016-12-01

    Full Text Available Purpose: The aim of this study is to investigate the basic features of climate change in Ukraine at 20th–21st centuries and to obtain an estimation of possible regional ecological consequences under influence of global warming. Methods: The empirical constants of the constructed semi-empirical models were estimated on the basis of the statistical analysis of materials of meteorological observations on meteorological stations of Ukraine for the XX century – beginning of XXІ century. The obtained results can be used to construct scenarios of the possible climate change in Ukraine at global warming in the near future. Results: The climatic conditions of Ukraine have definitely reacted to global warming (the annual temperature increased by 0.6±0.2 оС/100 years and insignificant increase of the annual sums of precipitations (5–7% for 100 years. The features of transformation of seasonal course of climatic fields of Ukraine of the temperature and atmospheric precipitations considered also. Taking into account global features of climate change are offered regional climate scenarios (temperature and precipitation in Ukraine for the 2050. Discussion: The analysis of the basic ecological consequences of global warming, which already happened or can be in the nearest future in Ukraine is carried out: increasing level of the Black sea and Sea of Azov; the spatiotemporal transformation of steppe phytosystem structure; changes in Northern Sea of Azov maritime spits ecosystems; excitation of catastrophic events in Ukraine, desertification process development in southern and southeast regions of Ukraine, climate change impacts on agriculture, aspects of water resources.

  15. Soil biological community structure in coffee (Coffea arabica L.) agroecosystems in the Caribbean

    Science.gov (United States)

    Coffee production in the Caribbean and Latin America is an important commodity in terms of economic, ecologic and social value. Coffee production in Puerto Rico was intensified in the 1960s, with the shift to higher-yield varieties, increased use of pesticides and fertilizers, increased mechanizati...

  16. Evapotranspiration models for a maize agro-ecosystem in irrigated and rainfed conditions

    Directory of Open Access Journals (Sweden)

    Arianna Facchi

    2013-09-01

    Full Text Available A high level of accuracy in the estimation of crop evapotranspiration (ET may lead to significant savings of economic and water resources in irrigated agriculture. Although ET is a fundamental process in many applications, it cannot be directly measured but it has to be estimated by monitoring the exchange of energy/water above the vegetated surface (micrometeorological methods, or as a residual term of the hydrological balance (lysimeters, soil water budget. The techniques to be adopted are often complex, costly and require specific equipment. Thus, since the ‘50s, many researchers have devoted their activity to the development of models for its estimation. The available approaches can be classified in “direct” methods, based on the original Penman-Monteith (PM equation, in which the canopy resistance rc is modelled, and “indirect” methods, based on the preliminary calculation of ET for a well-watered reference grass (ET0 with a constant rc, which is then multiplied by a crop coefficient Kc and, in case, by a stress coefficient Ks to obtain ET. Even if the latter approaches are more widely adopted for their practical simplicity, many authors show that the former often provide better ET estimates in absence of calibration of crop parameters. In this study the performances of different direct and indirect methods were evaluated in the case of a surface irrigated and of a rainfed maize grown in the Padana Plain (Northern Italy. The following models were considered: the “one-layer” original PM equation with three different models for rc (Monteith, Jarvis, Katerji-Perrier, the “two-layers” PM model proposed by Shuttleworth and Wallace, the “single” and “double” crop coefficient models illustrated in the Paper FAO-56. Latent heat fluxes measured in 2006 and 2011 in an experimental maize field by eddy-covariance were used to evaluate the models accuracy. Crop, soil and meteo data monitored contextually were used for the implementation of the different models. Results confirm that direct methods are more performing for both irrigated (2006 and rainfed (2011 conditions, with the SW model providing the best results and the FAO-56 models with generalized crop coefficients overestimating ET, especially during the middle growth stage.

  17. Effects of CO2 gas as leaks from geological storage sites on agro-ecosystems

    DEFF Research Database (Denmark)

    Patil, Ravi; Colls, Jeremy J; Steven, Michael D

    2010-01-01

    Carbon capture and storage in geological formations has potential risks in the long-term safety because of the possibility of CO2 leakage. Effects of leaking gas, therefore, on vegetation, soil, and soil-inhabiting organisms are critical to understand. An artificial soil gassing and response...

  18. Uncertainties in model predictions of nitrogen fluxes from agro-ecosystems in Europe

    Directory of Open Access Journals (Sweden)

    J. Kros

    2012-11-01

    Full Text Available To assess the responses of nitrogen and greenhouse gas emissions to pan-European changes in land cover, land management and climate, an integrated dynamic model, INTEGRATOR, has been developed. This model includes both simple process-based descriptions and empirical relationships and uses detailed GIS-based environmental and farming data in combination with various downscaling methods. This paper analyses the propagation of uncertainties in model inputs and parameters to outputs of INTEGRATOR, using a Monte Carlo analysis. Uncertain model inputs and parameters were represented by probability distributions, while spatial correlation in these uncertainties was taken into account by assigning correlation coefficients at various spatial scales. The uncertainty propagation was analysed for the emissions of NH3, N2O and NOx, N leaching to groundwater and N runoff to surface water for the entire EU27 and for individual countries. Results show large uncertainties for N leaching and runoff (relative errors of ∼ 19% for Europe as a whole, and smaller uncertainties for emission of N2O, NH3 and NOx (relative errors of ∼ 12%. Uncertainties for Europe as a whole were much smaller compared to uncertainties at country level, because errors partly cancelled out due to spatial aggregation.

  19. Greenhouse cultivation mitigates metal-ingestion-associated health risks from vegetables in wastewater-irrigated agroecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Chun [College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu (China); College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, Gansu (China); Chen, Xing-Peng; Ma, Zhen-Bang [College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu (China); Jia, Hui-Hui [State High-Tech Industrial Innovation Center, Shenzhen 518057, Guangdong (China); Wang, Jun-Jian, E-mail: junjian.wang@utoronto.ca [Department of Physical and Environmental Sciences, University of Toronto, Toronto M1C 1A4 (Canada)

    2016-08-01

    Wastewater irrigation can elevate metal concentrations in soils and crops and increase the metal-associated health risks via vegetable ingestion in arid and semiarid northwestern China. Here, we investigated the As, Cd, Cr, Cu, Ni, Pb, and Zn concentrations in four vegetable species from Dongdagou and Xidagou farmlands in Baiyin, Gansu, China. We evaluated the effects of irrigation type (Dongdagou: industrial wastewater; Xidagou: domestic wastewater) and cultivation mode (open field and greenhouse) on the vegetable metal concentration, metal partitioning, soil-to-plant bioconcentration factor (BCF), and the health risk index. All stream waters, soils, and vegetables were found most severely polluted by As and Cd, with higher severity in the industrial-wastewater-irrigated Dongdagou than the domestic-wastewater-irrigated Xidagou. All vegetables had higher or, at least, comparable metal mass allocated in the shoot than in the root. Greenhouse cultivation could reduce metal-ingestion-associated health risks from edible vegetable biomass by decreasing the soil to plant bioaccumulation (BCF) and the metal concentration. This effect was always significant for all vegetables within Xidagou, and for carrot within Dongdagou. This mitigation effect of greenhouse cultivation could be attributed to the metal sorption by a higher level of soil organic matter and faster growth rate over metal uptake rate in greenhouses compared to open fields. Such mitigation effect was, however, insignificant for leafy vegetables within Dongdagou, when much more severely polluted water for irrigation was applied in greenhouses compared to open fields within Dongdagou. The present study highlights greenhouse cultivation as a potential mitigating approach to providing less-polluted vegetables for residents in the severely polluted area in addition to the source pollution control. - Highlights: • Vegetable farmlands in Baiyin, Gansu, China were severely polluted by As and Cd. • Greenhouses had lower plant metal levels and bioconcentration factors than fields. • Greenhouse cultivation mitigated the health risks via vegetable ingestion. • Higher soil organic matter and faster growth in greenhouses may be the reasons.

  20. Including sugar cane in the agro-ecosystem model ORCHIDEE-STICS: calibration and validation

    Science.gov (United States)

    Valade, A.; Vuichard, N.; Ciais, P.; Viovy, N.

    2011-12-01

    Sugarcane is currently the most efficient bioenergy crop with regards to the energy produced per hectare. With approximately half the global bioethanol production in 2005, and a devoted land area expected to expand globally in the years to come, sugar cane is at the heart of the biofuel debate. Dynamic global vegetation models coupled with agronomical models are powerful and novel tools to tackle many of the environmental issues related to biofuels if they are carefully calibrated and validated against field observations. Here we adapt the agro-terrestrial model ORCHIDEE-STICS for sugar cane simulations. Observation data of LAI are used to evaluate the sensitivity of the model to parameters of nitrogen absorption and phenology, which are calibrated in a systematic way for six sites in Australia and La Reunion. We find that the optimal set of parameters is highly dependent on the sites' characteristics and that the model can reproduce satisfactorily the evolution of LAI. This careful calibration of ORCHIDEE-STICS for sugar cane biomass production for different locations and technical itineraries provides a strong basis for further analysis of the impacts of bioenergy-related land use change on carbon cycle budgets. As a next step, a sensitivity analysis is carried out to estimate the uncertainty of the model in biomass and carbon flux simulation due to its parameterization.

  1. Influences of agricultural management practices on Arbuscular Mycorrhiza Fungal symbioses in Kenyan agro-ecosystems

    NARCIS (Netherlands)

    Muriithi-Muchane, M.N.

    2013-01-01

    Conservation agriculture (CA) and integrated soil fertility management (ISFM) practices are receiving increased attention as pathways to sustainable high-production agriculture in sub-Saharan Africa. However, little is known about the effects of these practices on arbuscular mycorrhizal fungi (AMF).

  2. Molossid bats in an African agro-ecosystem select sugarcane fields as foraging habitat

    DEFF Research Database (Denmark)

    Noer, Christina Lehmkuhl; Dabelsteen, Torben; Bohmann, Kristine;

    2012-01-01

    their habitat utilization. The results confirmed that both of these species selected to forage over sugarcane fields instead of over the other habitats available in the area: savanna, riparian forest and urban areas. Foraging ranges were relatively large with C. pumilus travelling on average a maximum of 4.2 km...

  3. Small mammal populations of an agroecosystem in the Atlantic Forest domain, southeastern Brazil

    Directory of Open Access Journals (Sweden)

    PS. D’Andrea

    Full Text Available This study reports 2 years of the population dynamics and reproduction of a small mammal community using the removal method. The study was conducted in a rural area of the Atlantic Forest, in Sumidouro, Rio de Janeiro State, Brazil. The population sizes, age structure and reproduction were studied for the four most common species in the study area. The overall diversity was 1.67 and ranged between 0.8 to 1.67. The species richness was 13 considering the whole study. The most abundant species were the rodents Nectomys squamipes (n = 133, Akodon cursor (n = 74, Oligoryzomys nigripes (n = 25 and the marsupials Didelphis aurita (n = 58 and Philander frenatus (n = 50. Seven other rodents were captured once: Necromys lasiurus, Akodon montensis, Sooretamys angouya, Oecomys catherine, Oxymycterus judex, Euryzygomatomys spinosus and Trinomys iheringi. There were higher peaks for diversity and species richness during the winter (dry months, probably due to higher food availability. The marsupials had a seasonal reproduction with highest population sizes at the end of the rainy seasons. Nectomys squamipes reproduced mostly during rainy periods. Akodon cursor reproduced predominantly in the winter with the highest population peaks occurring during this season. The analysis of the population dynamics of the rodent species indicated that no species behaved as an agricultural pest, probably due to the heterogeneous landscape of high rotativity of vegetable cultivation. Rodent populations were more susceptible to the removal procedure than marsupial ones.

  4. Greenhouse cultivation mitigates metal-ingestion-associated health risks from vegetables in wastewater-irrigated agroecosystems.

    Science.gov (United States)

    Cao, Chun; Chen, Xing-Peng; Ma, Zhen-Bang; Jia, Hui-Hui; Wang, Jun-Jian

    2016-08-01

    Wastewater irrigation can elevate metal concentrations in soils and crops and increase the metal-associated health risks via vegetable ingestion in arid and semiarid northwestern China. Here, we investigated the As, Cd, Cr, Cu, Ni, Pb, and Zn concentrations in four vegetable species from Dongdagou and Xidagou farmlands in Baiyin, Gansu, China. We evaluated the effects of irrigation type (Dongdagou: industrial wastewater; Xidagou: domestic wastewater) and cultivation mode (open field and greenhouse) on the vegetable metal concentration, metal partitioning, soil-to-plant bioconcentration factor (BCF), and the health risk index. All stream waters, soils, and vegetables were found most severely polluted by As and Cd, with higher severity in the industrial-wastewater-irrigated Dongdagou than the domestic-wastewater-irrigated Xidagou. All vegetables had higher or, at least, comparable metal mass allocated in the shoot than in the root. Greenhouse cultivation could reduce metal-ingestion-associated health risks from edible vegetable biomass by decreasing the soil to plant bioaccumulation (BCF) and the metal concentration. This effect was always significant for all vegetables within Xidagou, and for carrot within Dongdagou. This mitigation effect of greenhouse cultivation could be attributed to the metal sorption by a higher level of soil organic matter and faster growth rate over metal uptake rate in greenhouses compared to open fields. Such mitigation effect was, however, insignificant for leafy vegetables within Dongdagou, when much more severely polluted water for irrigation was applied in greenhouses compared to open fields within Dongdagou. The present study highlights greenhouse cultivation as a potential mitigating approach to providing less-polluted vegetables for residents in the severely polluted area in addition to the source pollution control.

  5. Natural Enemies of the Frankliniella Complex Species (Thysanoptera: Thripidae) in Ataulfo Mango Agroecosystems.

    Science.gov (United States)

    Rocha, Franklin H; Infante, Francisco; Castillo, Alfredo; Ibarra-Nuñez, Guillermo; Goldarazena, Arturo; Funderburk, Joe E

    2015-01-01

    A field survey was conducted in Ataulfo mango (Mangifera indica L.) orchards in Chiapas, Mexico, with the objective of determining the natural enemies of the Frankliniella complex species (Thysanoptera: Thripidae). Seven species of this genus feed and reproduce in large numbers during the mango flowering. Two representative orchards were selected: the orchard "Tres A" characterized by an intensive use of agrochemicals directed against thrips, and the orchard "La Escondida" that did not spray insecticides. During mango flowering, five inflorescences were randomly collected every 5 d in both orchards, for a total of 18 sampling dates. Results revealed the presence of 18 species of arthropods that were found predating on Frankliniella. There were 11 species in the families Aeolothripidae, Phlaeothripidae, Formicidae, Anthocoridae and Chrysopidae; and seven species of spiders in the families Araneidae, Tetragnathidae, and Uloboridae. Over 88% of predators were anthocorids, including, Paratriphleps sp. (Champion), Orius insidiosus (Say), Orius tristicolor (White), and O. perpunctatus (Reuter). The orchard that did not spray insecticides had a significantly higher number of predators suggesting a negative effect of the insecticides on the abundance of these organisms.

  6. Soil respiration partition and its components in the total agro-ecosystem respiration

    Science.gov (United States)

    Delogu, Emilie; LeDantec, Valerie; Mordelet, Patrick; Buysse, Pauline; Aubinet, Marc; Pattey, Elizabeth; Mary, Bruno

    2013-04-01

    Close to 15% of the Earth's terrestrial surface is used for cropland. In the context of global warming, and acknowledged by the Kyoto Protocol, agricultural soils could be a significant sink for atmospheric CO2. Understanding the factors influencing carbon fluxes of agricultural soils is essential for implementing efficient mitigation practices. Most of the soil respiration modeling studies was carried out in forest ecosystems, but only a few was carried out in agricultural ecosystems. In the study, we evaluated simple formalisms to model soil respiration using wheat data from four contrasting geographical mi-latitude regions. Soil respiration were measured in three winter wheat fields at Lamasquère (43°49'N, 01°23'E, 2007) and Auradé (43°54'N, 01°10'E, 2008), South-West France and Lonzée (50°33'N, 4°44'E, 2007), Belgium, and in a spring wheat field at Ottawa (45°22'N, 75°43'W, 2007, 2011), Ontario, Canada. Manual closed chambers were used in the French sites. The Belgium and Canadian sites were equipped with automated closed chamber systems, which continuously collected 30-min soil respiration exchanges. All the sites were also equipped with eddy flux towers. When eddy flux data were collected over bare soil, the net ecosystem exchange (NEE) was equal to soil respiration exchange. These NEE data were used to validate the model. Different biotic and abiotic descriptors were used to model daily soil respiration and its heterotrophic and autotrophic components: soil temperature, soil relative humidity, Gross Primary Productivity (GPP), shoot biomass, crop height, with different formalisms. It was interesting to conclude that using biotic descriptors did not improve the performances of the model. In fact, a combination of abiotic descriptors (soil humidity and soil temperature) allowed significant model formalism to model soil respiration. The simple soil respiration model was used to calculate the heterotrophic and autotrophic source contributions to overall soil respiration and to estimate the soil respiration contribution to NEE measured at field scale. These different results have been compared and discussed for the wheat in four different conditions of soil and climate and the results showed that soil respiration consistently represented ~50% of the total ecosystem respiration. A significant portion of the heterotrophic soil respiration was influenced by the location and by the organic carbon content of the soils.

  7. Methyl salicylate attracts natural enemies and reduces populations of soybean aphids (Hemiptera: Aphididae) in soybean agroecosystems.

    Science.gov (United States)

    Mallinger, Rachel E; Hogg, David B; Gratton, Claudio

    2011-02-01

    Methyl salicylate, an herbivore-induced plant volatile, has been shown to attract natural enemies and affect herbivore behavior. In this study, methyl salicylate was examined for its attractiveness to natural enemies of the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), and for its direct effects on soybean aphid population growth rates. Methyl salicylate lures were deployed in plots within organic soybean [Glycine max (L.) Merr.] fields. Sticky card traps adjacent to and 1.5 m from the lure measured the relative abundance of natural enemies, and soybean aphid populations were monitored within treated and untreated plots. In addition, exclusion cage studies were conducted to determine methyl salicylate's effect on soybean aphid population growth rates in the absence of natural enemies. Significantly greater numbers of syrphid flies (Diptera: Syrphidae) and green lacewings (Neuroptera: Chrysopidae) were caught on traps adjacent to the methyl salicylate lure, but no differences in abundance were found at traps 1.5 m from the lure. Furthermore, abundance of soybean aphids was significantly lower in methyl salicylate-treated plots. In exclusion cage studies, soybean aphid numbers were significantly reduced on treated soybean plants when all plants were open to natural enemies. When plants were caged, however, soybean aphid numbers and population growth rates did not differ between treated and untreated plants suggesting no effect of methyl salicylate on soybean aphid reproduction and implicating the role of natural enemies in depressing aphid populations. Although aphid populations were reduced locally around methyl salicylate lures, larger scale studies are needed to assess the technology at the whole-field scale.

  8. Small mammal populations of an agroecosystem in the Atlantic Forest domain, southeastern Brazil.

    Science.gov (United States)

    D'Andrea, P S; Gentile, R; Maroja, L S; Fernandes, F A; Coura, R; Cerqueira, R

    2007-02-01

    This study reports 2 years of the population dynamics and reproduction of a small mammal community using the removal method. The study was conducted in a rural area of the Atlantic Forest, in Sumidouro, Rio de Janeiro State, Brazil. The population sizes, age structure and reproduction were studied for the four most common species in the study area. The overall diversity was 1.67 and ranged between 0.8 to 1.67. The species richness was 13 considering the whole study. The most abundant species were the rodents Nectomys squamipes (n = 133), Akodon cursor (n = 74), Oligoryzomys nigripes (n = 25) and the marsupials Didelphis aurita (n = 58) and Philander frenatus (n = 50). Seven other rodents were captured once: Necromys lasiurus, Akodon montensis, Sooretamys angouya, Oecomys catherine, Oxymycterus judex, Euryzygomatomys spinosus and Trinomys iheringi. There were higher peaks for diversity and species richness during the winter (dry) months, probably due to higher food availability. The marsupials had a seasonal reproduction with highest population sizes at the end of the rainy seasons. Nectomys squamipes reproduced mostly during rainy periods. Akodon cursor reproduced predominantly in the winter with the highest population peaks occurring during this season. The analysis of the population dynamics of the rodent species indicated that no species behaved as an agricultural pest, probably due to the heterogeneous landscape of high rotativity of vegetable cultivation. Rodent populations were more susceptible to the removal procedure than marsupial ones.

  9. Biochemical Impact of Fodder Galega (Galega orientalis Lam. on Agro-ecosystems

    Directory of Open Access Journals (Sweden)

    Ligita Baležentienė

    2011-12-01

    Full Text Available Multifunctional allelochemicals activities stimulate an increase in an employment spectrum of biologically active compounds in biological farming. The understanding of the allelochemical action mechanisms makes it possible to use these compounds to enhance crop production and develop a more sustainable agriculture, including weed and pest control through crop rotations, residue management and a variety of approaches in bio-control. The aim of this research was to establish and to compare the total amount of phenolic compounds and allelopathic activity of the aqueous extracts produced of different shoot parts (leaves, stems, blossoms and seed and roots of new crop, namely fodder galega at their different growth stages. Biochemical impact of the aqueous extracts produced of fodder galega ground part and roots on the germination data of the test–object subjected significantly on the galega growth stage and extract concentration. The biochemical effect of all tested extracts and concentrations had the same tendency to inhibit the test–object seed germination. The extracts of the ground part were more toxic than those of roots and had a stronger suppressive effect on the test–plant germination. Phenols concentration and conventional coumarine unit (CCU content increased evenly in dependence on total phenols concentration at all plant development stages accordingly to the extracts concentration gradient. Phenols concentration as well as their activity of ground part and roots increased from shooting to flowering stage.

  10. "Tinni" Rice ( Oryza rufipogon Griff.) Production: An Integrated Sociocultural Agroecosystem in Eastern Uttar Pradesh of India

    Science.gov (United States)

    Singh, Ranjay K.; Turner, Nancy J.; Pandey, C. B.

    2012-01-01

    This study reports how Traditional Ecological Knowledge (TEK) and informal cultural institutions have conserved key varieties of the wildgrowing rice, ` tinni' (red rice, or brownbeard rice, Oriza rufipogon Griff.), within the Bhar community of eastern Uttar Pradesh, India. The study was conducted, using conventional and participatory methods, in 10 purposively selected Bhar villages. Two distinct varieties of tinni (` tinni patali' and ` tinni moti') with differing habitats and phenotypic characters were identified. Seven microecosystems (Kari, Badaila, Chammo, Karmol, Bhainsiki, Bhainsala and Khodailia) were found to support these varieties in differing proportions. Tinni rice can withstand more extreme weather conditions (the highest as well as lowest temperatures and rainfall regimes) than the `genetically improved' varieties of rice ( Oriza sativa L.) grown in the region. Both tinni varieties are important bioresources for the Bhar's subsistence livelihoods, and they use distinctive conservation approaches in their maintenance. Bhar women are the main custodians of tinni rice agrobiodiversity, conserving tinni through an institution called Sajha. Democratic decision-making at meetings organized by village elders determines the market price of the tinni varieties. Overall, the indigenous institutions and women's participation seem to have provided safeguards from excessive exploitation of tinni rice varieties. The maintenance of tinni through cultural knowledge and institutions serves as an example of the importance of locally maintained crop varieties in contributing to people's resilience and food security in times of rapid social and environmental change.

  11. EVOLUTION OF SOME COMPONENTS OF AGROECOSYSTEMS PRODUCTIVITY FROM VINGA PLAIN IN WATER STRESS SITUATIONS

    Directory of Open Access Journals (Sweden)

    Daniel Dicu

    2011-12-01

    Full Text Available The researches are inscribed on line of substantiation of durable agricultural system, having as main objective the prominence of quantitative and qualitative modifications made on agro-system level under the effect of no-tillage system for wheat, maize and soybeans. The experimental field is placed on a cambic chernozem, with a medium content of clay, dominant in the Prodagro West Arad agro-centre and representative for a large surface in the Banat-Crisana Plain. The passing to no-till system change the structure of technological elements, through less soil works, so the impact on agro-system is different comparing with conventional tillage, first less the intervention pressure on agro-system ant secondly appear new interactions, new equilibriums and disequilibriums. Considering the evolution of soil humidity, the observations made monthly (by taking soil samples and laboratory determinations for the three cultures showed that in the no-till system, there are more uniform values in the soil profile, and in the variants where the deep work of soil was made it could be observed a low increase of the water volume in the soil.

  12. Seasonal infestations of two stem borers (Lepidoptera: Crambidae) in noncrop grasses of Gulf Coast rice agroecosystems

    Science.gov (United States)

    Infestations of two stem borers, the Mexican rice borer, Eoreuma loftini (Dyar) and the sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), were compared in non-crop grasses adjacent to rice, Oryza sativa L., fields. Three farms in the Texas Gulf Coast rice production area were sur...

  13. Arbuscular Mycorrhizal (AM) Diversity in Prosopis cineraria (L.) Druce Under Arid Agroecosystems

    Institute of Scientific and Technical Information of China (English)

    Neelam Verma; Jagadish Chandra Tarafdar; Krishna Kant Srivastava; Jitendra Panwar

    2008-01-01

    Arbuscular mycorrhizal (AM) fungi associated with Prosopis cineraria (Khejri) were assessed for their qualitative and quantitative distribution from eight districts of Rajasthan. A total of three species of Acaulospora, one species of Entrophospora, two species of Gigaspora, twenty-one species of Glomus, seven species of Sclerocystis and three species of Scutellospora were recorded. A high diversity of AM fungi was observed and it varied at different study sites. Among these six genera, Glomus occurred most frequently. Glomus fasciculatum, Glomus aggregatum, and Glomus mosseae were found to be the most predominant AM fungi in infecting Prosopis cineraria. Acaulospora, G. fasciculatum, Sclerocystis was found in all the fields studied, while Scutellospora species were found only in few sites. A maximum of thirty-six AM fungal species were isolated and identified from Jodhpur, whereas only thirteen species were found from Jaisalmer. Spores of Glomus fasciculatum were found to be most abundant under Prosopis cineraria.

  14. Agro(EcoSystem Services—Supply and Demand from Fields to Society

    Directory of Open Access Journals (Sweden)

    Benjamin Burkhard

    2016-04-01

    Full Text Available Land use—with a special focus on agriculture—is increasingly influenced by globalization and external driving forces, causing farmers to seek opportunities to develop efficient, large-scale production systems.[...

  15. Genomic Regulation of the Response of an Agroecosystem to Elements of Global Change

    Energy Technology Data Exchange (ETDEWEB)

    DeLucia, Evan, H.

    2011-06-03

    This document outlines some of the major accomplishments from this project: (1) New tools for analyzing and visualizing microarray data from soybean gene expression experiments; (2) Physiological, biochemical, and gene array evidence that acclimation of carbon metabolism to elevated CO{sub 2} is governed in significant part by changes in gene expression associated with respiratory metabolism; (3) Increased carbon assimilation in soybeans grown at elevated CO{sub 2} altered pools of carbohydrates and transcripts that control growth and expansion of young leaves; (4) Growth at elevated CO{sub 2} increases the abundance of transcripts controlling cell wall polysaccharide synthesis but not transcripts controlling lignin synthesis; (5) The total antioxidant capacity of soybeans varies among cultivars and in response to atmospheric change; (6) Accelerated leaf senescence at elevated O{sub 3} coincides with reduced abundance of transcripts controlling protein synthesis; (7) Growth under elevated CO{sub 2} increases the susceptibility of soybean to insect herbivores by increasing insect lifespan and fecundity through altered leaf chemistry and by defeating molecular induction of plant defenses; (8) Exposure to elevated CO{sub 2} and O{sub 3} alters flavonoid metabolism in soybean; (9) Exposure to elevated CO{sub 2} or O{sub 3} conferred resistance to soybean mosaic virus by cross inducing defense- and stress-related signaling pathways; and (10) Exposure to elevated CO{sub 2} accelerates decomposition by changing chemical and biotic properties of the soil.

  16. Central Russia agroecosystem monitoring with CO2 fluxes analysis by eddy covariance method

    Directory of Open Access Journals (Sweden)

    Joulia Meshalkina

    2015-07-01

    Full Text Available The eddy covariance (EC technique as a powerful statistics-based method of measurement and calculation the vertical turbulent fluxes of greenhouses gases within atmospheric boundary layers provides the continuous, long-term flux information integrated at the ecosystem scale. An attractive way to compare the agricultural practices influences on GHG fluxes is to divide a crop area into subplots managed in different ways. The research has been carried out in the Precision Farming Experimental Field of the Russian Timiryazev State Agricultural University (RTSAU, Moscow in 2013 under the support of RF Government grant # 11.G34.31.0079, EU grant # 603542 LUС4С (7FP and RF Ministry of education and science grant # 14-120-14-4266-ScSh. Arable Umbric Albeluvisols have around 1% of SOC, 5.4 pH (KCl and NPK medium-enhanced contents in sandy loam topsoil. The CO2 flux seasonal monitoring has been done by two eddy covariance stations located at the distance of 108 m. The LI-COR instrumental equipment was the same for the both stations. The stations differ only by current crop version: barley or vetch and oats. At both sites, diurnal patterns of NEE among different months were very similar in shape but varied slightly in amplitude. NEE values were about zero during spring time. CO2 fluxes have been intensified after crop emerging from values of 3 to 7 µmol/s∙m2 for emission, and from 5 to 20 µmol/s∙m2 for sink. Stabilization of the fluxes has come at achieving plants height of 10-12 cm. Average NEE was negative only in June and July. Maximum uptake was observed in June with average values about 8 µmol CO2 m−2 s−1. Although different kind of crops were planted on the fields A and B, GPP dynamics was quite similar for both sites: after reaching the peak values at the mid of June, GPP decreased from 4 to 0.5 g C CO2 m-2 d-1 at the end of July. The difference in crops harvesting time that was equal two weeks did not significantly influence the daily GPP patterns. Cumulative assimilation of CO2 at the end of the growing season was about 150 g C m−2 for both sites. So the difference in NEE was the consequence of essentially higher respiration rates in case of vetch and oats (about 350 g C m−2 comparing to barley (250 g C m−2 that needs additional research. The results have shown high daily and seasonal dynamic of CO2 emission too as a result of different and contrasted conditions: crop type, crop development stage, soil moisture and air temperature. Obtained unique for Russian agriculture data are useful for land-use practices environmental assessment, for soil organic carbon dynamics analysis and agroecological evaluation.

  17. Habitat- and density-dependent demography of a colonial raptor in Mediterranean agro-ecosystems

    OpenAIRE

    2016-01-01

    Agricultural intensification is considered the major cause of decline in farmland bird populations, especially in the Mediterranean region. Food shortage increased by the interaction between agricultural intensification and density-dependent mechanisms could influence the population dynamics of colonial birds.Weused demographic data on lesser kestrels (Falco naumanni), a key species of Mediterranean pseudo-steppes, to understand the importance of land-use changes and density-dependent mechani...

  18. The interaction between soil erosion and soil organisms in temperate agroecosystems: nematode redistribution in tramlines

    Science.gov (United States)

    Baxter, Craig; Rowan, John S.; McKenzie, Blair M.; Neilson, Roy

    2014-05-01

    Arable agriculture presents a unique set of challenges, and one of the most important is soil erosion. Whilst policy and practice look towards sustainable intensification of production to ensure food security, fundamental gaps in our understanding still exist. The physical processes involved in the detachment, transport and deposition of soil are well characterised but further research considering chemical and nutrient transport, fertiliser and pesticide losses, and environmental impacts to downstream environments is still required. Furthermore the interaction between soil erosion and soil organisms have largely been ignored, even though soil organisms serve a myriad of functions essential in the provision of soil ecosystem goods and services. Here we present the findings of a field-scale experiment into soil biotic redistribution undertaken at the James Hutton Institute's Balruddery Farm, Scotland (Link Tramlines Project XDW8001). Farm vehicle-tyre wheelings left in arable fields (tramlines) to enable crop spraying during the crop growth cycle have been identified as key transport pathways for sediment and associated nutrients. We tested the hypothesis that soil organisms were also transported by tramline erosion. During the winter of 2012/13 an experiment was undertaken to measure soil organism export from unbound hillslope plots subject to four different tramline treatments set out in a randomised block design. We used soil nematodes as a model organism as they are ubiquitous and sensitive to disturbance and an established indicator taxa of biological and physico-chemical changes in soil. Tramline treatments included a control tyre (conventional tractor tyre), a control tyre with a sown tramline, a low pressure tyre with sown tramline, and a control tyre with a spiked harrow. Post-event sampling of rainfall events was undertaken, and a range of variables measured in the laboratory. The spiked harrow treatment produced the greatest overall reductions in nematode export with 95% less nematodes exported, compared with the control treatment. We observed wholesale non-selective transport of all nematode trophic groups present in the soil. The findings of this experiment are twofold. Firstly, we demonstrate that soil organisms are transported by erosion processes and confirm that tramlines are key hydrological pathways. Secondly, we highlight practical on-farm solutions that have potential to decrease soil organism losses. These results provide important baseline information to improve our understanding of soil erosion impacts to the wider soil ecosystem. The results help to inform soil and water conservation measures for sustainable agriculture.

  19. REGIONAL EMISSIONS OF NITRIC OXIDE (NO) AND CARBON DIOXIDE (CO2) IN AGROECOSYSTEMS IN CENTRAL WEST REGION, BRAZIL.

    Science.gov (United States)

    The Central West Region in Brazil has been the focus of intense agricultural expansion since the 1970s and, nowadays, a large area of native cerrado has been converted to agricultural use. The expansion was accompanied by intensive use of fertilizer, irrigation and management pra...

  20. Spatial variability of soil salinity at different scales in the mangrove rice agro-ecosystem in West Africa.

    NARCIS (Netherlands)

    Sylla, M.; Stein, A.; Breemen, van N.; Fresco, L.O.

    1995-01-01

    Spatial variability of soil salinity in coastal low lands results from a complex interaction of climate, river hydrology, topography and tidal flooding. The aim of this study was to determine the significant effects of these causal factors at different scales in the West African mangrove environment

  1. Diversity and communities of foliar endophytic fungi from different agroecosystems of Coffea arabica L. in two regions of Veracruz, Mexico.

    Directory of Open Access Journals (Sweden)

    Aurora Saucedo-García

    Full Text Available Over the past 20 years, the biodiversity associated with shaded coffee plantations and the role of diverse agroforestry types in biodiversity conservation and environmental services have been topics of debate. Endophytic fungi, which are microorganisms that inhabit plant tissues in an asymptomatic manner, form a part of the biodiversity associated with coffee plants. Studies on the endophytic fungi communities of cultivable host plants have shown variability among farming regions; however, the variability in fungal endophytic communities of coffee plants among different coffee agroforestry systems is still poorly understood. As such, we analyzed the diversity and communities of foliar endophytic fungi inhabiting Coffea arabica plants growing in the rustic plantations and simple polycultures of two regions in the center of Veracruz, Mexico. The endophytic fungi isolates were identified by their morphological traits, and the majority of identified species correspond to species of fungi previously reported as endophytes of coffee leaves. We analyzed and compared the colonization rates, diversity, and communities of endophytes found in the different agroforestry systems and in the different regions. Although the endophytic diversity was not fully recovered, we found differences in the abundance and diversity of endophytes among the coffee regions and differences in richness between the two different agroforestry systems of each region. No consistent pattern of community similarity was found between the coffee agroforestry systems, but we found that rustic plantations shared the highest number of morphospecies. The results suggest that endophyte abundance, richness, diversity, and communities may be influenced predominantly by coffee region, and to a lesser extent, by the agroforestry system. Our results contribute to the knowledge of the relationships between agroforestry systems and biodiversity conservation and provide information regarding some endophytic fungi and their communities as potential management tools against coffee plant pests and pathogens.

  2. Modeling the effects of saline groundwater and irrigation water on root zone salinity and sodicity dynamics in agro-ecosystems

    NARCIS (Netherlands)

    Shah, S.H.H.

    2013-01-01

    Recent trends and future projections suggest that the need to produce more food and fibre for the world’ s expanding population will lead to an increase in the use of marginal-quality water and land resources (Bouwer, 2000; Gupta and Abrol, 2000; Wild, 2003). This is particularly relevant to l

  3. Occurrence and Distribution of Banana bunchy top virus Related Agro-Ecosystem in South Western, Democratic Republic of Congo

    OpenAIRE

    Mukwa Fama Tongo, Lyna; Muengula, Marcel; Zinga, I; Kalonji, Adrien; Iskra-Caruana, M.L.; Bragard, Claude

    2014-01-01

    Banana bunchy top virus (BBTV) is one of the most severe and widespread virus limiting produc- tion and distribution of planting material of banana (Musa spp.) crops in the world. In Democratic Republic of Congo (DRC), these crops play a major role in daily life of almost 70% of citizen. Many factors influence banana production negatively such as Banana bunchy top disease. Epidemiol- ogical survey was conducted in experimental stations and farmers’ fields for two consecutive sea- sons coverin...

  4. Distribuição de Carabidae e Staphylinidae em agroecossistemas Distribution of Carabidae and Staphylinidae in agroecosystems

    Directory of Open Access Journals (Sweden)

    Francisco Jorge Cividanes

    2008-02-01

    Full Text Available O objetivo deste trabalho foi determinar a distribuição da riqueza de espécies e a preferência pelo habitat de Carabidae e Staphylinidae (Coleoptera, em áreas com rotação de soja e milho, em plantio direto e convencional, e em áreas adjacentes a estas com fragmento florestal e povoamento de pínus, respectivamente. Os besouros foram amostrados por meio de armadilhas de solo distribuídas em dois transectos de 100 m de comprimento. A distribuição da riqueza de espécies nas culturas, no fragmento florestal e no pínus foi avaliada por meio de análise de regressão linear. A análise de agrupamento foi empregada para identificar as espécies quanto à preferência pelos habitats: fragmento florestal, pínus, cultura e interface. A distribuição da riqueza de espécies de Carabidae e Staphylinidae não variou em relação à posição no transecto, enquanto a riqueza de espécies observada nas interfaces foi elevada em comparação com a encontrada nos demais habitats. A ocorrência de espécies de Carabidae diferiu conforme o tipo de cobertura vegetal: Megacephala sp. e Scarites sp. preferiram áreas cultivadas em sistema de rotação soja-milho; Odontochila nodicornis (Dejean preferiu o fragmento florestal e o povoamento de pínus. A espécie Abaris basistriatus Chaudoir caracterizou-se como generalista quanto à preferência pelo habitat.The objective of this work was to determine the distribution of species richness and habitat preference of Carabidae and Staphylinidae (Coleoptera in two areas cultivated with soybean/corn under no-tillage and conventional tillage systems and in adjacents areas with forest fragment and a Pinus stand, respectively. Beetles were sampled by pitfall traps which were distributed in two transects of 100 m. The distribution of species richness in the crops and forest fragment/Pinus was evaluated by regression analysis. Cluster analysis was used to identify species in relation to preference for the forest fragment, Pinus, crop and interface. The distribution of Carabidae and Staphylinidae species richness did not show variation in relation to the position in transect, while the species richness observed in the interfaces between forest fragment or Pinus stand and crops were higher compared with the ones found in other habitats. The occurrence of Carabidae species differed in relation to the vegetation type: Megacephala sp. and Scarites sp. preferred crop areas under soybean/corn rotation system. The same was observed with Odontochila nodicornis (Dejean in the forest fragment and Pinus stand. The species Abaris basistriatus Chaudoir was characterized as a generalist species in relation to habitat preference.

  5. Climate Change and Potato Production in Contrasting South African Agro-Ecosystems 2. Assessing Risks and Opportunities of Adaptation Strategies

    NARCIS (Netherlands)

    Franke, A.C.; Haverkort, A.J.; Steyn, J.M.

    2013-01-01

    This study aims to assess the risks and opportunities posed by climate change to potato growers in South Africa and to evaluate adaptation measures in the form of changes in planting time growers could adopt to optimise land and water use efficiencies in potato, using a climate model of past, presen

  6. Combined effects of climatic gradient and domestic livestock grazing on reptile community structure in a heterogeneous agroecosystem.

    Science.gov (United States)

    Rotem, Guy; Gavish, Yoni; Shacham, Boaz; Giladi, Itamar; Bouskila, Amos; Ziv, Yaron

    2016-01-01

    Grazing plays an important role in shaping ecological communities in human-related ecosystems. Although myriad studies have explored the joint effect of grazing and climate on plant communities, this interactive effect has rarely been studied in animals. We hypothesized that the effect of grazing on the reptile community varies along a climatic gradient in relation to the effect of grazing on habitat characteristics, and that grazing differentially affects reptiles of different biogeographic regions. We tested our hypotheses by collecting data on environmental characteristics and by trapping reptiles in four heterogeneous landscapes experiencing differing grazing intensities and distributed along a sharp climatic gradient. We found that while reptile diversity increased with grazing intensity at the mesic end of the gradient, it decreased with grazing intensity at the arid end. Moreover, the proportion of reptile species of differing biogeographic origins varied with the interactive effect of climate and grazing. The representation of species originating in arid biogeographic zones was highest at the arid end of the climatic gradient, and representation increased with grazing intensity within this area. Regardless of the climatic context, increased grazing pressure results in a reduction in vegetation cover and thus in changes in habitat characteristics. By reducing vegetation cover, grazing increased habitat heterogeneity in the dense mesic sites and decreased habitat heterogeneity in the arid sites. Thus, our results suggest that the same direction of habitat alteration caused by grazing may have opposite effects on biodiversity and community composition in different climatic contexts.

  7. Soil Functional Zone Management: A Vehicle for Enhancing Production and Soil Ecosystem Services in Row-Crop Agroecosystems

    Science.gov (United States)

    Williams, Alwyn; Kane, Daniel A.; Ewing, Patrick M.; Atwood, Lesley W.; Jilling, Andrea; Li, Meng; Lou, Yi; Davis, Adam S.; Grandy, A. Stuart; Huerd, Sheri C.; Hunter, Mitchell C.; Koide, Roger T.; Mortensen, David A.; Smith, Richard G.; Snapp, Sieglinde S.; Spokas, Kurt A.; Yannarell, Anthony C.; Jordan, Nicholas R.

    2016-01-01

    There is increasing global demand for food, bioenergy feedstocks and a wide variety of bio-based products. In response, agriculture has advanced production, but is increasingly depleting soil regulating and supporting ecosystem services. New production systems have emerged, such as no-tillage, that can enhance soil services but may limit yields. Moving forward, agricultural systems must reduce trade-offs between production and soil services. Soil functional zone management (SFZM) is a novel strategy for developing sustainable production systems that attempts to integrate the benefits of conventional, intensive agriculture, and no-tillage. SFZM creates distinct functional zones within crop row and inter-row spaces. By incorporating decimeter-scale spatial and temporal heterogeneity, SFZM attempts to foster greater soil biodiversity and integrate complementary soil processes at the sub-field level. Such integration maximizes soil services by creating zones of ‘active turnover’, optimized for crop growth and yield (provisioning services); and adjacent zones of ‘soil building’, that promote soil structure development, carbon storage, and moisture regulation (regulating and supporting services). These zones allow SFZM to secure existing agricultural productivity while avoiding or minimizing trade-offs with soil ecosystem services. Moreover, the specific properties of SFZM may enable sustainable increases in provisioning services via temporal intensification (expanding the portion of the year during which harvestable crops are grown). We present a conceptual model of ‘virtuous cycles’, illustrating how increases in crop yields within SFZM systems could create self-reinforcing feedback processes with desirable effects, including mitigation of trade-offs between yield maximization and soil ecosystem services. Through the creation of functionally distinct but interacting zones, SFZM may provide a vehicle for optimizing the delivery of multiple goods and services in agricultural systems, allowing sustainable temporal intensification while protecting and enhancing soil functioning. PMID:26904043

  8. SUSTAINABLE DEVELOPMENT MANAGEMENT OF THE GRASSLAND AGROECOSYSTEM IN THE CONTEXT OF BIODIVERSITY CONSERVATION AND IMPROVEMENT OF PERMANENT GRASSLAND

    Directory of Open Access Journals (Sweden)

    Pompilica IAGARU

    2015-04-01

    Full Text Available The agricultural enterprise, seen from a sustainable development perspective, operates within an ecosystem, and aims to achieve a harmonious interpenetration and integration with it. The way in which this interpenetration and integration is realized depends on the level achieved by its performances, which requires the adoption of policies and strategies and the economic organization of biotechnical processes. The paper emphasizes an interdisciplinary approach to issues like management and sustainable development of the grassland agro ecosystem and shows that promoting ecological techniques in the grassland agro ecosystem can ensure its versatility. All these supported by obtaining appropriate pastoral values, namely biodiversity conservation and improvement of meadows, and knowing that Romania has a variety of floral structures with high biodiversity indices.

  9. Evaluation of a regional air-quality model with bidirectional NH3 exchange coupled to an agroecosystem modelecosystem model

    Science.gov (United States)

    Atmospheric ammonia (NH3) is the primary atmospheric base and an important precursor for inorganic particulate matter and when deposited NH3 contributes to surface water eutrophication, soil acidification and decline in species biodiversity. Flux measurement...

  10. Increase phosphorus availability from the use of alfalfa (Medicago sativa L) green manure in rice (Oryza sativa L.) agroecosystem.

    Science.gov (United States)

    Gao, Xiaoye; Shi, Dongyan; Lv, Aimin; Wang, Shengyin; Yuan, Shili; Zhou, Peng; An, Yuan

    2016-11-11

    Alfalfa is a good green manure source, but its effect on rice growth has not been fully elucidated. Two green manure species, alfalfa and broad bean (Vicia faba L.), and two N fertilizer levels, alone or combination, were applied to a rice field. The results indicated that alfalfa had more pronounced effects on increasing soil labile phosphorus (P) fractions (including NaHCO3-Pi, NaOH-Pi), P uptake and soil enzyme activities (dehydrogenase, urease, acid phosphatase and β-glucosidase) than broad bean and N fertilizer. The transformation of NaHCO3-Po to labile P regulated by alfalfa played a significant direct and indirect effect on grain yield. Although a much lower N input from alfalfa addition, a similar grain yield with N fertilizer treatment was achieved, and the integration of alfalfa with N fertilizer produced the highest grain yield and P availability, which was associated with the highest urease, acid phosphatase and β-glucosidase activity in soil. These results indicate that alfalfa green manure had a great ability of increasing grain yield through enhancing P availability in rice paddy, which could give us a way to reduce N fertilizer application by enhancing P availability.

  11. Characteristics of AVIRIS Band Measurements in Desert Agroecosystems in the Area of Blythe, California. 1; Studies of Cotton Spectra

    Science.gov (United States)

    Hanna, Safwat H. Shakir

    2001-01-01

    Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data from Blythe, California, were acquired in June 1997 to study agricultural spectra from different crops and to identify crops in other areas with similar environmental factors and similar spectral properties. The main objectives of this study are: (1) to compare the spectral and radiometric characteristics of AVIRIS data from agriculture crops with ground spectra measured by a FieldSpec ASD spectrometer; (2) to explore the use of AVIRIS spectral images for identifying agricultural crops; (3) to study the spectral expression of environmental factors on selected crops; and (4) to build a spectral library for the crops that were studied. A long-term goal is to extend the spectral library for different vegetation or crops in different stages of growth. To support our study, on July 18 and 19, 2000, we collected spectra using the FieldSpec spectrometer from selected fields with different crops in the Blythe area of California (longitude 114 deg 33.28 W and latitude 33 deg 25.42 N to longitude 1140 44.53 W and latitude 33 deg 39.77 N). These crops were cotton in different stages of growth, varieties of grass pure or mixed, Sudan grass, Bermuda grass, Teff grass, and alfalfa. Some of the fields were treated with different types of irrigation (i.e., wet to dry conditions). Additional parameters were studied such as the soil water content (WC), pH, and organic matter (OM). The results of this study showed that for crops known to be similar, there is a significant correlation between the spectra that were collected by AVIRIS in 1997 and spectra measured by the FieldSpec (registered) spectrometer in 2000. This correlation allowed development of a spectral library to be used in ENVI-IDL analysis software. This library was used successfully to identify different crops. Furthermore, using IDL algorithms of Spectral Angle Mapper classification (SAM), spectral feature fitting (SFF) and spectral binary encoding (SPE) showed that there is excellent agreement between the predicted and the actual crop type (i.e., the correlation is between 85-90% match). Further use of the AVIRIS images can be of a value to crop identification or crop yield for commercial use.

  12. Impacts of bioenergy feedstock production on environmental factors in the Central U.S. using an agroecosystem model (Invited)

    Science.gov (United States)

    Twine, T. E.; Vanloocke, A. D.; Williams, M.; Bernacchi, C.

    2010-12-01

    The Renewable Fuel Standard in the Energy Independence and Security Act of 2007 requires annual U.S. production of 36 billion gallons of renewable fuels by 2022, nearly half of this from cellulosic biofuels. We have little guidance as to where to grow bioenergy feedstocks to maximize yield without competing for food resources, and little understanding of the environmental and economic impacts of their production. Furthermore, it is unclear how bioenergy feedstocks might be incorporated into the current landscape to minimize environmental consequences. Numerical models allow us to predict environmental impacts across large spatial domains and long time periods by simulating the response of potential feedstocks to drivers such as soil type and climate. We used the Agro-IBIS (Integrated Biosphere Simulator, agricultural version) model to quantify the impacts on Midwest U.S. water and energy budgets from land use for bioenergy production. We analyzed effects of changes in land cover (e.g., from current crops to perennial grasses) as well as changes in management (e.g., removal of crop residues for fuel). Our analyses indicate that perennial grasses can substantially increase evapotranspiration (water transport to the atmosphere) in locations where fraction cover is greater than 25%. This change in evapotranspiration is lowest in regions where current crops and grasses are highly productive and evapotranspiration is large, and is highest in semi-arid regions where productivity is lower. These results imply that growing bioenergy feedstocks on marginal lands could have substantial effects on water resources.

  13. Diversity and communities of foliar endophytic fungi from different agroecosystems of Coffea arabica L. in two regions of Veracruz, Mexico.

    Science.gov (United States)

    Saucedo-García, Aurora; Anaya, Ana Luisa; Espinosa-García, Francisco J; González, María C

    2014-01-01

    Over the past 20 years, the biodiversity associated with shaded coffee plantations and the role of diverse agroforestry types in biodiversity conservation and environmental services have been topics of debate. Endophytic fungi, which are microorganisms that inhabit plant tissues in an asymptomatic manner, form a part of the biodiversity associated with coffee plants. Studies on the endophytic fungi communities of cultivable host plants have shown variability among farming regions; however, the variability in fungal endophytic communities of coffee plants among different coffee agroforestry systems is still poorly understood. As such, we analyzed the diversity and communities of foliar endophytic fungi inhabiting Coffea arabica plants growing in the rustic plantations and simple polycultures of two regions in the center of Veracruz, Mexico. The endophytic fungi isolates were identified by their morphological traits, and the majority of identified species correspond to species of fungi previously reported as endophytes of coffee leaves. We analyzed and compared the colonization rates, diversity, and communities of endophytes found in the different agroforestry systems and in the different regions. Although the endophytic diversity was not fully recovered, we found differences in the abundance and diversity of endophytes among the coffee regions and differences in richness between the two different agroforestry systems of each region. No consistent pattern of community similarity was found between the coffee agroforestry systems, but we found that rustic plantations shared the highest number of morphospecies. The results suggest that endophyte abundance, richness, diversity, and communities may be influenced predominantly by coffee region, and to a lesser extent, by the agroforestry system. Our results contribute to the knowledge of the relationships between agroforestry systems and biodiversity conservation and provide information regarding some endophytic fungi and their communities as potential management tools against coffee plant pests and pathogens.

  14. Soil Hydrological Attributes of an Integrated Crop-Livestock Agroecosystem: Increased Adaptation through Resistance to Soil Change

    Directory of Open Access Journals (Sweden)

    Mark A. Liebig

    2011-01-01

    Full Text Available Integrated crop-livestock systems have been purported to have significant agronomic and environmental benefits compared to specialized, single-enterprise production systems. However, concerns exist regarding the effect of livestock in integrated systems to cause soil compaction, thereby decreasing infiltration of water into soil. Such concerns are compounded by projections of more frequent high-intensity rainfall events from anticipated climate change, which would act to increase surface runoff and soil erosion. A study was conducted to evaluate the effects of residue management, frequency of hoof traffic, season, and production system (e.g., integrated annual cropping versus perennial grass on infiltration rates from 2001 through 2008 in central North Dakota, USA. Imposed treatments had no effect on infiltration rate at three, six, and nine years after study establishment, implying that agricultural producers should not be concerned with inhibited infiltration in integrated annual cropping systems, where winter grazing is used. The use of no-till management, coupled with annual freeze/thaw and wet/dry cycles, likely conferred an inherent resistance to change in near-surface soil properties affecting soil hydrological attributes. Accordingly, caution should be exercised in applying these results to other regions or management systems.

  15. Changes in soil microbial community structure influenced by agricultural management practices in a mediterranean agro-ecosystem.

    Directory of Open Access Journals (Sweden)

    Fuensanta García-Orenes

    Full Text Available Agricultural practices have proven to be unsuitable in many cases, causing considerable reductions in soil quality. Land management practices can provide solutions to this problem and contribute to get a sustainable agriculture model. The main objective of this work was to assess the effect of different agricultural management practices on soil microbial community structure (evaluated as abundance of phospholipid fatty acids, PLFA. Five different treatments were selected, based on the most common practices used by farmers in the study area (eastern Spain: residual herbicides, tillage, tillage with oats and oats straw mulching; these agricultural practices were evaluated against an abandoned land after farming and an adjacent long term wild forest coverage. The results showed a substantial level of differentiation in the microbial community structure, in terms of management practices, which was highly associated with soil organic matter content. Addition of oats straw led to a microbial community structure closer to wild forest coverage soil, associated with increases in organic carbon, microbial biomass and fungal abundances. The microbial community composition of the abandoned agricultural soil was characterised by increases in both fungal abundances and the metabolic quotient (soil respiration per unit of microbial biomass, suggesting an increase in the stability of organic carbon. The ratio of bacteria:fungi was higher in wild forest coverage and land abandoned systems, as well as in the soil treated with oat straw. The most intensively managed soils showed higher abundances of bacteria and actinobacteria. Thus, the application of organic matter, such as oats straw, appears to be a sustainable management practice that enhances organic carbon, microbial biomass and activity and fungal abundances, thereby changing the microbial community structure to one more similar to those observed in soils under wild forest coverage.

  16. Climate change and agroecosystems: the effect of elevated atmospheric CO2 and temperature on crop growth, development, and yield

    Directory of Open Access Journals (Sweden)

    Streck Nereu Augusto

    2005-01-01

    Full Text Available The amount of carbon dioxide (CO2 of the Earths atmosphere is increasing, which has the potential of increasing greenhouse effect and air temperature in the future. Plants respond to environment CO2 and temperature. Therefore, climate change may affect agriculture. The purpose of this paper was to review the literature about the impact of a possible increase in atmospheric CO2 concentration and temperature on crop growth, development, and yield. Increasing CO2 concentration increases crop yield once the substrate for photosynthesis and the gradient of CO2 concentration between atmosphere and leaf increase. C3 plants will benefit more than C4 plants at elevated CO2. However, if global warming will take place, an increase in temperature may offset the benefits of increasing CO2 on crop yield.

  17. Dietary selection in Mastomys natalensis (Rodentia: Muridae) in the maize agro-ecosystems of central and southwestern Tanzania

    DEFF Research Database (Denmark)

    Odhiambo, Richard O; Makundi, Rhodes H; Leirs, Herwig;

    2008-01-01

    We studied the feeding habits of Mastomys natalensis by analysing a total of 2934 stomachs from individuals snap trapped from maize fields and the surrounding fallow land of central and southwestern Tanzania between February 2001 and October 2002. Mastomys natalensis had a wide range of food item...

  18. Genetically modified (GM) corn in the Philippines : Ecological impacts on agroecosystems, effects on the economic status and farmers’ experiences

    NARCIS (Netherlands)

    Mabutol-Afidchao, Miladis B.

    2013-01-01

    To seek answers to the issues on GM corn adoption in the Philippines, the thesis focused to find answers on the general question: How can genetically modified (GM) corn and its attributed changes in agricultural practices affect the agro-ecosystem’s biodiversity and the economic status and social li

  19. Long-term agroecosystem research in the central Mississippi river basin: hyperspectral remote sensing of reservoir water quality.

    Science.gov (United States)

    Sudduth, Kenneth A; Jang, Gab-Sue; Lerch, Robert N; Sadler, E John

    2015-01-01

    In situ methods for estimating water quality parameters would facilitate efforts in spatial and temporal monitoring, and optical reflectance sensing has shown potential in this regard, particularly for chlorophyll, suspended sediment, and turbidity. The objective of this research was to develop and evaluate relationships between hyperspectral remote sensing and lake water quality parameters-chlorophyll, turbidity, and N and P species. Proximal hyperspectral water reflectance data were obtained on seven sampling dates for multiple arms of Mark Twain Lake, a large man-made reservoir in northeastern Missouri. Aerial hyperspectral data were also obtained on two dates. Water samples were collected and analyzed in the laboratory for chlorophyll, nutrients, and turbidity. Previously reported reflectance indices and full-spectrum (i.e., partial least squares regression) methods were used to develop relationships between spectral and water quality data. With the exception of dissolved NH, all measured water quality parameters were strongly related ( ≥ 0.7) to proximal reflectance across all measurement dates. Aerial hyperspectral sensing was somewhat less accurate than proximal sensing for the two measurement dates where both were obtained. Although full-spectrum calibrations were more accurate for chlorophyll and turbidity than results from previously reported models, those previous models performed better for an independent test set. Because extrapolation of estimation models to dates other than those used to calibrate the model greatly increased estimation error for some parameters, collection of calibration samples at each sensing date would be required for the most accurate remote sensing estimates of water quality.

  20. Does the Honey Bee "Risk Cup" Runneth Over? Estimating Aggregate Exposures for Assessing Pesticide Risks to Honey Bees in Agroecosystems.

    Science.gov (United States)

    Berenbaum, May R

    2016-01-13

    Honey bees (Apis mellifera) are uniquely vulnerable to nontarget pesticide impacts because, as ubiquitous managed pollinators, they are deliberately transported into areas where crops are grown with pesticides. Moreover, attributes making them excellent managed pollinators, including large long-lived colonies and complex behavior, also make them challenging subjects for toxicity bioassays. For over 150 years, improvements in formulation and delivery of pesticides, increasing their environmental and temporal presence, have had unintended consequences for honey bees. Since 1996, the Environmental Protection Agency has used "aggregate risk"--exposure risks to all possible sources--to set tolerances; once a "risk cup" is filled, no new pesticide or use can be approved unless risks are reduced elsewhere. The EPA now recommends a modeling approach for aggregating all exposure risks for bees, with differential lifestage sensitivity and exposure probabilities. Thus, the honey bee is the first insect with its own "risk cup"--a technological innovation that may not have unintended consequences for this beleaguered beneficial species.

  1. Gasification biochar has limited effects on functional and structural diversity of soil microbial communities in a temperate agroecosystem

    DEFF Research Database (Denmark)

    Imparato, Valentina; Hansen, Veronika; Santos, Susana;

    2016-01-01

    ) of wheat straw gasification biochar (GBC) and fresh straw incorporated as soil amendments into an agricultural field in Denmark. Soils were analysed three months after the amendments for pH, total organic matter, microbial biomass (ATP), ten enzymatic activities, catabolic potential by substrate......-induced respiration (MicroResp™), soil toxicity test (BioTox™) and bacterial community structure (Illumina 16S rRNA gene sequencing). No significant effect of biochar treatment was observed regarding ATP content, catabolic community profiles and soil toxicity. The higher dose of GBC increased phenol oxidase activity...... and soil pH, and decreased the cellulase activity. No major effect of high dose GBC was observed on the soil community diversity, and only minor effect on the community composition, with an increase in the relative abundance of a single OTU associated with Acidobacteria_Gp16. Addition of low dose of GBC...

  2. Nutrient and carbon cycling in agro-ecosystems and their interactions with ecosystem services. 27th Francis New Memorial Lecture

    NARCIS (Netherlands)

    Neeteson, J.J.

    2011-01-01

    Ecosystem services are the benefits people obtain from ecosystems. An ecosystem is the interacting system of living organisms and their associated non-living environment. Four types of ecosystem services can be distinguished: provisioning services, regulating services, cultural services, and support

  3. Gasification biochar has limited effects on functional and structural diversity of soil microbial communities in a temperate agroecosystem

    DEFF Research Database (Denmark)

    Imparato, Valentina; Hansen, Veronika; Santos, Susana

    2016-01-01

    and soil pH, and decreased the cellulase activity. No major effect of high dose GBC was observed on the soil community diversity, and only minor effect on the community composition, with an increase in the relative abundance of a single OTU associated with Acidobacteria_Gp16. Addition of low dose of GBC......Biochar may enhance soil fertility and carbon (C) sequestration but there is still a lack of comprehensive understanding of its effects on soil microbial communities and functioning. This study tested the differential effects of two doses (6e8 and 0.8e1.4 t ha1 for High and Low doses, respectively......) of wheat straw gasification biochar (GBC) and fresh straw incorporated as soil amendments into an agricultural field in Denmark. Soils were analysed three months after the amendments for pH, total organic matter, microbial biomass (ATP), ten enzymatic activities, catabolic potential by substrate...

  4. Comparison greenhouse gas (GHG) emissions and global warming potential (GWP) effect of energy use in different wheat agroecosystems in Iran.

    Science.gov (United States)

    Yousefi, Mohammad; Mahdavi Damghani, Abdolmajid; Khoramivafa, Mahmud

    2016-04-01

    The aims of this study were to determine energy requirement and global warming potential (GWP) in low and high input wheat production systems in western of Iran. For this purpose, data were collected from 120 wheat farms applying questionnaires via face-to-face interviews. Results showed that total energy input and output were 60,000 and 180,000 MJ ha(-1) in high input systems and 14,000 and 56,000 MJ ha(-1) in low input wheat production systems, respectively. The highest share of total input energy in high input systems recorded for electricity power, N fertilizer, and diesel fuel with 36, 18, and 13 %, respectively, while the highest share of input energy in low input systems observed for N fertilizer, diesel fuel, and seed with 32, 31, and 27 %. Energy use efficiency in high input systems (3.03) was lower than of low input systems (3.94). Total CO2, N2O, and CH4 emissions in high input systems were 1981.25, 31.18, and 1.87 kg ha(-1), respectively. These amounts were 699.88, 0.02, and 0.96 kg ha(-1) in low input systems. In high input wheat production systems, total GWP was 11686.63 kg CO2eq ha(-1) wheat. This amount was 725.89 kg CO2eq ha(-1) in low input systems. The results show that 1 ha of high input system will produce greenhouse effect 17 times of low input systems. So, high input production systems need to have an efficient and sustainable management for reducing environmental crises such as change climate.

  5. Smallholders' soil fertility management in the Central Highlands of Ethiopia: implications for nutrient stocks, balances and sustainability of agroecosystems

    NARCIS (Netherlands)

    A. Haileslassie; J.A. Priess; E. Veldkamp; J.P. Lesschen

    2006-01-01

    Low agricultural productivity caused by soil degradation is a serious problem in the Ethiopian Highlands. Here, we report how differences in soil fertility management between farming systems, based either on enset (Ensete ventricosum) or on teff (Eragrostis tef) as the major crops, affect the extent

  6. Current situation and perspective of the multi-use of Arachis pintoi in agro-ecosystems devoted to animal production

    Directory of Open Access Journals (Sweden)

    Verónica Andrade Yucailla

    2016-07-01

    Full Text Available This paper realized an analysis of the scientific literature in which 75 articles were reviewed from indexed Journals in specialized databases and of international recognition about the main aspects reviewed such as the origin, adaptation conditions in areas of the humid tropic, genetic aspects related to the chromosomal markers; demonstrating a big morphologic variability in the germplasms. Inside of the potential uses of major relevancy there was stand out the use as soil coverage and as soil improver, as well as weeds controller, presenting a positive effect in the content of organic matter and nitrogen of soil. The use of Arachis pintoi Frapovickas y Gregory in the animal feeding systems is a resource of high quality; it can be a viable alternative for the animal production systems in the tropic. The impact of some agroecological practices on the agroproductive parameters with the use of A. pintoi is of the important relevancy. It was concludes that A. pintoi presents a potential of multiple use in integrated systems of crops - trees – livestock, constituting an alternative of sustainable management of the tropical animal production.

  7. Soil Erosion and Nutrient Losses control by Plant Covers: Environmental Implications for a Subtropical Agroecosystem (SE Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Pleguezuelo, C. R.; Duran-Zuazo, V. H.; Martin-Peinado, F. J.; Franco-Tarifa, D.; Martinez-Raya, A.; Francia-Martinez, J. R.; Carceles-Rodriguez, B.; Arroyo-Panadero, L.; Casado, J. P.

    2009-07-01

    Soil erosion, in addition to causing on-site loss of topsoil and reducing the productivity of the land, brings about major off-site environmental effects such as water body pollution and eutrophication. In the Mediterranean area, this fact is especially relevant where precipitation is characterized by scarcity, torrent storms and extreme variability in space and time. To study the effects of soil erosion runoff potential pollution we installed six erosion plots on the taluses of orchard terraces where an intensive irrigated agriculture based on subtropical crops has been established. (Author)

  8. Increase phosphorus availability from the use of alfalfa (Medicago sativa L) green manure in rice (Oryza sativa L.) agroecosystem

    Science.gov (United States)

    Gao, Xiaoye; Shi, Dongyan; Lv, Aimin; Wang, Shengyin; Yuan, Shili; Zhou, Peng; An, Yuan

    2016-01-01

    Alfalfa is a good green manure source, but its effect on rice growth has not been fully elucidated. Two green manure species, alfalfa and broad bean (Vicia faba L.), and two N fertilizer levels, alone or combination, were applied to a rice field. The results indicated that alfalfa had more pronounced effects on increasing soil labile phosphorus (P) fractions (including NaHCO3-Pi, NaOH-Pi), P uptake and soil enzyme activities (dehydrogenase, urease, acid phosphatase and β-glucosidase) than broad bean and N fertilizer. The transformation of NaHCO3-Po to labile P regulated by alfalfa played a significant direct and indirect effect on grain yield. Although a much lower N input from alfalfa addition, a similar grain yield with N fertilizer treatment was achieved, and the integration of alfalfa with N fertilizer produced the highest grain yield and P availability, which was associated with the highest urease, acid phosphatase and β-glucosidase activity in soil. These results indicate that alfalfa green manure had a great ability of increasing grain yield through enhancing P availability in rice paddy, which could give us a way to reduce N fertilizer application by enhancing P availability. PMID:27833163

  9. Cassava Mosaic Disease Yield Loss Assessment under Various Altitude Agroecosystems in the Sud Kivu Region, Democratic Republic of Congo

    Directory of Open Access Journals (Sweden)

    Bisimwa, E.

    2015-01-01

    Full Text Available Cassava mosaic disease (CMD is reported as the most important constraint on cassava production in Sub­Saharan Africa. Yield losses of 25­95% are reported. The use of resistant genotypes is one of the components for its integrated management. However its impact on genotype behavior depends on infection period, age of the infected plants, environment and virus species or strain. This study was carried out to assess its impact in farmers' fields and the behavior of 14 genotypes under high epidemic pressure in the Sud­Kivu province, in the East of Democratic Republic of Congo (DRC. Early infections have induced 77.5% to 97.3% of yield losses whereas 44.9 to 80% were recorded for cassava plants infected during thirteenth to twenty­fourth weeks after planting. The highest yield losses were recorded in low altitude where more EACMV­UG and dual infections were reported. Improved resistant genotypes MM96/002, MM96/0157 and MM96/1920 allowed harvesting more than 30 T/ha and didn't show any symptoms whereas MM96/6967 and Mvuama have developed symptoms at harvest. Local landraces were susceptible to CMD and developed symptoms during the whole season until harvest. However two of them, Pharmakina and Cizinduka yielded more than 50 T/ha of tubers and associated symptoms were moderate. Two improved and two local cassava genotypes are recommended in this area always making sure to use healthy cuttings.

  10. Soil type and texture impacts on soil organic carbon accumulation in a sub-tropical agro-ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Gonçalves, Daniel Ruiz Potma; Sa, Joao Carlos de Moraes; Mishra, Umakant; Cerri, Carlos Eduardo Pellegrino; Ferreira, Lucimara Aparecida; Furlan, Flavia Juliana Ferreira

    2016-11-02

    Soil organic carbon (C) plays a fundamental role in tropical and subtropical soil fertility, agronomic productivity, and soil health. As a tool for understand ecosystems dynamics, mathematical models such as Century have been used to assess soil's capacity to store C in different environments. However, as Century was initially developed for temperate ecosystems, several authors have hypothesized that C storage may be underestimated by Century in Oxisols. We tested the hypothesis that Century model can be parameterized for tropical soils and used to reliably estimate soil organic carbon (SOC) storage. The aim of this study was to investigate SOC storage under two soil types and three textural classes and quantify the sources and magnitude of uncertainty using the Century model. The simulation for SOC storage was efficient and the mean residue was 10 Mg C ha-1 (13%) for n = 91. However, a different simulation bias was observed for soil with <600 g kg-1 of clay was 16.3 Mg C ha-1 (18%) for n = 30, and at >600 g kg-1 of clay, was 4 Mg C ha-1 (5%) for n = 50, respectively. The results suggest a non-linear effect of clay and silt contents on C storage in Oxisols. All types of soil contain nearly 70% of Fe and Al oxides in the clay fraction and a regression analysis showed an increase in model bias with increase in oxides content. Consequently, inclusion of mineralogical control of SOC stabilization by Fe and Al (hydro) oxides may improve results of Century model simulations in soils with high oxides contents

  11. Biosolids and dredged materials: alternative sources of nutrients for crop productivity and sustainability of pasture-based agroecosystem

    Science.gov (United States)

    Domestic sewage sludge or “biosolids” and lake-dredged materials are examples of materials that can be used to cut fertilizer costs in pasture-based animal agriculture. Sustainable biosolids and lake-dredged materials management is based upon controlling and influencing the quantity, quality and cha...

  12. Gasification biochar has limited effects on functional and structural diversity of soil microbial communities in a temperate agroecosystem

    DEFF Research Database (Denmark)

    Imparato, Valentina; Hansen, Veronika; Santos, Susana;

    2016-01-01

    -induced respiration (MicroResp™), soil toxicity test (BioTox™) and bacterial community structure (Illumina 16S rRNA gene sequencing). No significant effect of biochar treatment was observed regarding ATP content, catabolic community profiles and soil toxicity. The higher dose of GBC increased phenol oxidase activity......Biochar may enhance soil fertility and carbon (C) sequestration but there is still a lack of comprehensive understanding of its effects on soil microbial communities and functioning. This study tested the differential effects of two doses (6-8 and 0.8-1.4 t ha-1 for High and Low doses, respectively......) of wheat straw gasification biochar (GBC) and fresh straw incorporated as soil amendments into an agricultural field in Denmark. Soils were analysed three months after the amendments for pH, total organic matter, microbial biomass (ATP), ten enzymatic activities, catabolic potential by substrate...

  13. Diversity and Communities of Foliar Endophytic Fungi from Different Agroecosystems of Coffea arabica L. in Two Regions of Veracruz, Mexico

    Science.gov (United States)

    Saucedo-García, Aurora; Anaya, Ana Luisa; Espinosa-García, Francisco J.; González, María C.

    2014-01-01

    Over the past 20 years, the biodiversity associated with shaded coffee plantations and the role of diverse agroforestry types in biodiversity conservation and environmental services have been topics of debate. Endophytic fungi, which are microorganisms that inhabit plant tissues in an asymptomatic manner, form a part of the biodiversity associated with coffee plants. Studies on the endophytic fungi communities of cultivable host plants have shown variability among farming regions; however, the variability in fungal endophytic communities of coffee plants among different coffee agroforestry systems is still poorly understood. As such, we analyzed the diversity and communities of foliar endophytic fungi inhabiting Coffea arabica plants growing in the rustic plantations and simple polycultures of two regions in the center of Veracruz, Mexico. The endophytic fungi isolates were identified by their morphological traits, and the majority of identified species correspond to species of fungi previously reported as endophytes of coffee leaves. We analyzed and compared the colonization rates, diversity, and communities of endophytes found in the different agroforestry systems and in the different regions. Although the endophytic diversity was not fully recovered, we found differences in the abundance and diversity of endophytes among the coffee regions and differences in richness between the two different agroforestry systems of each region. No consistent pattern of community similarity was found between the coffee agroforestry systems, but we found that rustic plantations shared the highest number of morphospecies. The results suggest that endophyte abundance, richness, diversity, and communities may be influenced predominantly by coffee region, and to a lesser extent, by the agroforestry system. Our results contribute to the knowledge of the relationships between agroforestry systems and biodiversity conservation and provide information regarding some endophytic fungi and their communities as potential management tools against coffee plant pests and pathogens. PMID:24887512

  14. Changes in soil microbial community structure influenced by agricultural management practices in a mediterranean agro-ecosystem.

    Science.gov (United States)

    García-Orenes, Fuensanta; Morugán-Coronado, Alicia; Zornoza, Raul; Cerdà, Artemi; Scow, Kate

    2013-01-01

    Agricultural practices have proven to be unsuitable in many cases, causing considerable reductions in soil quality. Land management practices can provide solutions to this problem and contribute to get a sustainable agriculture model. The main objective of this work was to assess the effect of different agricultural management practices on soil microbial community structure (evaluated as abundance of phospholipid fatty acids, PLFA). Five different treatments were selected, based on the most common practices used by farmers in the study area (eastern Spain): residual herbicides, tillage, tillage with oats and oats straw mulching; these agricultural practices were evaluated against an abandoned land after farming and an adjacent long term wild forest coverage. The results showed a substantial level of differentiation in the microbial community structure, in terms of management practices, which was highly associated with soil organic matter content. Addition of oats straw led to a microbial community structure closer to wild forest coverage soil, associated with increases in organic carbon, microbial biomass and fungal abundances. The microbial community composition of the abandoned agricultural soil was characterised by increases in both fungal abundances and the metabolic quotient (soil respiration per unit of microbial biomass), suggesting an increase in the stability of organic carbon. The ratio of bacteria:fungi was higher in wild forest coverage and land abandoned systems, as well as in the soil treated with oat straw. The most intensively managed soils showed higher abundances of bacteria and actinobacteria. Thus, the application of organic matter, such as oats straw, appears to be a sustainable management practice that enhances organic carbon, microbial biomass and activity and fungal abundances, thereby changing the microbial community structure to one more similar to those observed in soils under wild forest coverage.

  15. Multi-Isotopic (δ2H, δ13C, δ15N) Tracing of Molt Origin for Red-Winged Blackbirds Associated with Agro-Ecosystems

    Science.gov (United States)

    Werner, Scott J.; Hobson, Keith A.; Van Wilgenburg, Steven L.; Fischer, Justin W.

    2016-01-01

    We analyzed stable-hydrogen (δ2H), carbon (δ13C) and nitrogen (δ 15N) isotope ratios in feathers to better understand the molt origin and food habits of Red-winged Blackbirds (Agelaius phoeniceus) near sunflower production in the Upper Midwest and rice production in the Mid-South of the United States. Outer primary feathers were used from 661 after-second-year (ASY) male blackbirds collected in Minnesota, Montana, North Dakota and South Dakota (spring collection), and Arkansas, Louisiana, Mississippi, Missouri and Texas (winter collection). The best-fit model indicated that the combination of feather δ2H, δ13C and δ15N best predicted the state of sample collections and thus supported the use of this approach for tracing molt origins in Red-winged Blackbirds. When considering only birds collected in spring, 56% of birds were classified to their collection state on the basis of δ2H and δ13C alone. We then developed feather isoscapes for δ13C based upon these data and for δ2H based upon continental patterns of δ2H in precipitation. We used 81 birds collected at the ten independent sites for model validation. The spatially-explicit assignment of these 81 birds to the δ2H isoscape resulted in relatively high rates (~77%) of accurate assignment to collection states. We also modeled the spatial extent of C3 (e.g. rice, sunflower) and C4 (corn, millet, sorghum) agricultural crops grown throughout the Upper Midwest and Mid-South United States to predict the relative use of C3- versus C4-based foodwebs among sampled blackbirds. Estimates of C3 inputs to diet ranged from 50% in Arkansas to 27% in Minnesota. As a novel contribution to blackbird conservation and management, we demonstrate how such feather isoscapes can be used to predict the molt origin and interstate movements of migratory blackbirds for subsequent investigations of breeding biology (e.g. sex-specific philopatry), agricultural depredation, feeding ecology, physiology of migration and sensitivity to environmental change. PMID:27846302

  16. Pesticide residue concentration in soil following conventional and Low-Input Crop Management in a Mediterranean agro-ecosystem, in Central Greece

    Energy Technology Data Exchange (ETDEWEB)

    Karasali, Helen, E-mail: e.karassali@bpi.gr [Laboratory of Chemical Control of Pesticides, Department of Pesticides Control and Phytopharmacy, Benaki Phytopathological Institute, 8 St. Delta Street, Kifissia, 14561 Athens (Greece); Marousopoulou, Anna [Laboratory of Chemical Control of Pesticides, Department of Pesticides Control and Phytopharmacy, Benaki Phytopathological Institute, 8 St. Delta Street, Kifissia, 14561 Athens (Greece); Machera, Kyriaki, E-mail: k.machera@bpi.gr [Laboratory of Pesticides Toxicology, Department of Pesticides Control and Phytopharmacy, Benaki Phytopathological Institute, 8 St. Delta Street, Kifissia, 14561 Athens (Greece)

    2016-01-15

    The present study was focused on the comparative evaluation of pesticide residues, determined in soil samples from Kopaida region, Greece before and after the implementation of Low-Input Crop Management (LCM) protocols. LCM has been suggested as an environmental friendly plant protection approach to be applied on crops growing in vulnerable to pollution ecosystems, with special focus on the site specific problems. In the case of the specific pilot area, the vulnerability was mainly related to the pollution of water bodies from agrochemicals attributed to diffuse pollution primarily from herbicides and secondarily from insecticides. A total of sixty-six soil samples, were collected and analyzed during a three-year monitoring study and the results of the determined pesticide residues were considered for the impact evaluation of applied plant protection methodology. The LCM was developed and applied in the main crops growing in the pilot area i.e. cotton, maize and industrial tomato. Herbicides active ingredients such as ethalfluralin, trifluralin, pendimethalin, S-metolachlor and fluometuron were detected in most samples at various concentrations. Ethalfluralin, which was the active ingredient present in the majority of the samples ranged from 0.01 μg g{sup −1} to 0.26 μg g{sup −1} soil dry weight. However, the amount of herbicides measured after the implementation of LCM for two cropping periods, was reduced by more than 75% in all cases. The method of analysis was based on the simultaneous extraction of the target compounds by mechanical shaking, followed by liquid chromatography mass spectrometric and gas chromatography electron capture (LC–MS/MS and GC–ECD) analysis. - Highlights: • Effect of Low Input Crop Management (LCM) in a vulnerable to pollution ecosystem. • LCM resulted in herbicide residues reduction in the range of 75 and 100% in all cases. • Conventional practices resulted in increased herbicide residues up to 18%. • Anthropogenic changes have the potential to change pollution levels.

  17. Cotton as an entry point for soil fertility maintenance and food crop productivity in savannah agroecosystems - Evidence from a long-term experiment in southern Mali

    NARCIS (Netherlands)

    Ripoche, A.; Crétenet, M.; Corbeels, M.; Affholder, F.; Naudin, K.; Sissoko, F.; Douzet, J.M.; Tittonell, P.A.

    2015-01-01

    Given the scarcity of manure and the limited land available for fallowing, cotton cultivation with its input credit schemes is often the main entry point for nutrients in cropping systems of West Africa. In an experiment carried out during 25 years in southern Mali, the crop and soil responses to or

  18. B-esterase activities and blood cell morphology in the frog Leptodactylus chaquensis (Amphibia: Leptodactylidae) on rice agroecosystems from Santa Fe Province (Argentina).

    Science.gov (United States)

    Attademo, Andrés M; Cabagna-Zenklusen, Mariana; Lajmanovich, Rafael C; Peltzer, Paola M; Junges, Celina; Bassó, Agustín

    2011-01-01

    Activity of B-esterases (BChE: butyrylcholinesterase and CbE: carboxylesterase using two model substrates: α-naphthyl acetate and 4-nitrophenyl valerate) in a native frog, Leptodactylus chaquensis from rice fields (RF1: methamidophos and RF2: cypermethrin and endosulfan sprayed by aircraft) and non-contaminated area (pristine forest) was measured. The ability of pyridine-2-aldoxime methochloride (2-PAM) to reactivate BChE levels was also explored. In addition, changes in blood cell morphology and parasite infection were determined. Mean values of plasma BChE activities were lower in samples from the two rice fields than in those from the reference site. CbE (4-nitrophenyl valerate) levels varied in the three sites studied, being highest in RF1. Frog plasma from RF1 showed positive reactivation of BChE activity after incubation with 2-PAM. Blood parameters of frogs from RF2 revealed morphological alterations (anisochromasia and immature erythrocytes frequency). Moreover, a major infection of protozoan Trypanosoma sp. in individuals from the two rice fields was detected. We suggest that integrated use of several biomarkers (BChE and CBEs, chemical reactivation of plasma with 2-PAM, and blood cell parameters) may be a promising procedure for use in biomonitoring programmes to diagnose pesticide exposure of wild populations of this frog and other native anuran species in Argentina.

  19. Intercropping with shrub species that display a 'steady-state' flowering phenology as a strategy for biodiversity conservation in tropical agroecosystems.

    Directory of Open Access Journals (Sweden)

    Valerie E Peters

    Full Text Available Animal species in the Neotropics have evolved under a lower spatiotemporal patchiness of food resources compared to the other tropical regions. Although plant species with a steady-state flowering/fruiting phenology are rare, they provide predictable food resources and therefore may play a pivotal role in animal community structure and diversity. I experimentally planted a supplemental patch of a shrub species with a steady-state flowering/fruiting phenology, Hamelia patens Jacq., into coffee agroforests to evaluate the contribution of this unique phenology to the structure and diversity of the flower-visiting community. After accounting for the higher abundance of captured animals in the coffee agroforests with the supplemental floral resources, species richness was 21% higher overall in the flower-visiting community in these agroforests compared to control agroforests. Coffee agroforests with the steady-state supplemental floral patch also had 31% more butterfly species, 29% more hummingbird species, 65% more wasps and 85% more bees than control coffee agroforests. The experimental treatment, together with elevation, explained 57% of the variation in community structure of the flower-visiting community. The identification of plant species that can support a high number of animal species, including important ecosystem service providers, is becoming increasingly important for restoration and conservation applications. Throughout the Neotropics plant species with a steady-state flowering/fruiting phenology can be found in all aseasonal forests and thus could be widely tested and suitable species used throughout the tropics to manage for biodiversity and potentially ecosystem services involving beneficial arthropods.

  20. Intercropping with shrub species that display a 'steady-state' flowering phenology as a strategy for biodiversity conservation in tropical agroecosystems.

    Science.gov (United States)

    Peters, Valerie E

    2014-01-01

    Animal species in the Neotropics have evolved under a lower spatiotemporal patchiness of food resources compared to the other tropical regions. Although plant species with a steady-state flowering/fruiting phenology are rare, they provide predictable food resources and therefore may play a pivotal role in animal community structure and diversity. I experimentally planted a supplemental patch of a shrub species with a steady-state flowering/fruiting phenology, Hamelia patens Jacq., into coffee agroforests to evaluate the contribution of this unique phenology to the structure and diversity of the flower-visiting community. After accounting for the higher abundance of captured animals in the coffee agroforests with the supplemental floral resources, species richness was 21% higher overall in the flower-visiting community in these agroforests compared to control agroforests. Coffee agroforests with the steady-state supplemental floral patch also had 31% more butterfly species, 29% more hummingbird species, 65% more wasps and 85% more bees than control coffee agroforests. The experimental treatment, together with elevation, explained 57% of the variation in community structure of the flower-visiting community. The identification of plant species that can support a high number of animal species, including important ecosystem service providers, is becoming increasingly important for restoration and conservation applications. Throughout the Neotropics plant species with a steady-state flowering/fruiting phenology can be found in all aseasonal forests and thus could be widely tested and suitable species used throughout the tropics to manage for biodiversity and potentially ecosystem services involving beneficial arthropods.

  1. Use of video surveillance to measure the influences of habitat management and landscape composition on pollinator visitation and pollen deposition in pumpkin (Cucurbita pepo agroecosystems

    Directory of Open Access Journals (Sweden)

    Benjamin W. Phillips

    2015-11-01

    Full Text Available Pumpkin (Cucurbita pepo production relies on insect-mediated pollination, which is provided by managed and wild pollinators. The goals of this study were to measure the visitation frequency, longevity and temporal activity patterns of pumpkin pollinators and to determine if local habitat management and landscape composition affected this pollination service. We used video surveillance to monitor bee acitivty within male and female pumpkin flowers in 2011 and 2012 across a pollination window of 0600–1200 h. We also quantified the amount of pollen deposited in female flowers across this time period. In 2011, A. mellifera made significantly more floral visits than other bees, and in 2012 Bombus spp. was the dominant pumpkin pollinator. We found variation in visitation among male and female pumpkin flowers, with A. mellifera visiting female flowers more often and spending longer per visit within them than male flowers in both 2011 and 2012. The squash bee P. pruinosa visited male flowers more frequently in 2012, but individuals spent equal time in both flower sexes. We did not find variation in the timing of flower visitation among species across the observed pollination window. In both 2011 and 2012 we found that the majority of pollen deposition occurred within the first two hours (0600–0800 h of observation; there was no difference between the pollen deposited during this two-hour period and full pollination window (0600–1200 h. Local additions of sweet alyssum floral strips or a field buffer strip of native wildflowers did not have an effect on the foraging activity of bees or pollen deposition. However, semi-natural and urban habitats in the surrounding landscape were positively correlated with the frequency of flower visitation by wild pollinators and the amount of pollen deposited within female flowers.

  2. Integration of Ground and Multi-Resolution Satellite Data for Predicting the Water Balance of a Mediterranean Two-Layer Agro-Ecosystem

    Directory of Open Access Journals (Sweden)

    Piero Battista

    2016-09-01

    Full Text Available The estimation of site water budget is important in Mediterranean areas, where it represents a crucial factor affecting the quantity and quality of traditional crop production. This is particularly the case for spatially fragmented, multi-layer agricultural ecosystems such as olive groves, which are traditional cultivations of the Mediterranean basin. The current paper aims at demonstrating the effectiveness of spatialized meteorological data and remote sensing techniques to estimate the actual evapotranspiration (ETA and the soil water content (SWC of an olive orchard in Central Italy. The relatively small size of this orchard (about 0.1 ha and its two-layer structure (i.e., olive trees and grasses require the integration of remotely sensed data with different spatial and temporal resolutions (Terra-MODIS, Landsat 8-OLI and Ikonos. These data are used to drive a recently proposed water balance method (NDVI-Cws and predict ETA and then site SWC, which are assessed through comparison with sap flow and soil wetness measurements taken in 2013. The results obtained indicate the importance of integrating satellite imageries having different spatio-temporal properties in order to properly characterize the examined olive orchard. More generally, the experimental evidences support the possibility of using widely available remotely sensed and ancillary datasets for the operational estimation of ETA and SWC in olive tree cultivation systems.

  3. AESIS: a support tool for the evaluation of sustainability of agroecosystems. Example of applications to organic and integrated farming systems in Tuscany, Italy

    Directory of Open Access Journals (Sweden)

    Gaio Cesare Pacini

    2011-02-01

    Full Text Available Agricultural researchers widely recognise the importance of sustainable agricultural production systems and the need to develop appropriate methods to measure sustainability on the farm level. Policy makers need accounting and evaluation tools to be able to assess the potential of sustainable production practices and to provide appropriate agro-environmental policy measures. Farmers are in search of sustainable management tools to cope with regulations and enhance efficiency. This paper presents the outcomes of applications to organic and integrated farming of an indicator-based framework to evaluate sustainability of farming systems (Agro-Environmental Sustainability Information System, AESIS. The AESIS was described together with a review of applications dating from 1991 in a previous paper. The objective of the present paper is to present the AESIS application to organic and integrated farming systems in Val d’Elsa (Tuscany and discuss how it is adapted for application to ordinary farms. The AESIS is organised into a number of environmental and production systems. For each system, environmental critical points are identified with corresponding agro-environmental indicators and processing methods. Possible solutions to sustainability issues, and critical points of relevance to the agricultural sector of the local economic and agro-ecological zone, are formulated by including an experimental layout, identifying indicator thresholds and by defining management systems with corresponding policy measures. Alternative solutions are evaluated by calculating and measuring the relevant indicators. The outcomes of the AESIS applications are discussed with specific relevance to the operational adoptability of AESIS to ordinary, agri-touristic farms managed with the organic and the integrated production method, respectively. The AESIS framework proved to be sufficiently flexible to meet the requirements for ordinary farm applications while keeping a holistic perspective and considering pedo-climatic and production factors on different spatial scales.

  4. Biodiversity and integrated pest management in agroecosystems%农田生物多样性与害虫综合治理

    Institute of Scientific and Technical Information of China (English)

    尤民生; 刘雨芳; 侯有明

    2004-01-01

    在现代农田生态系统中,人类为了满足自身的需要,通常把自然界的植物群落改造成大面积种植单种特定的作物,人为地排除其他植物种类的竞争以提高作物的产量.由于单一化的作物不断取代自然植被,降低了农田的物种和生境多样性,结果导致农田生态系统的不稳定和害虫问题的更加恶化.影响农田生物多样性的因素很多,如地理位置、气候类型、环境条件、作物品种、种间关系、人类的栽培活动等.根据现有的生态学原理和研究成果,人类可以通过采用适当的措施来恢复和强化农田生物多样性,提高天敌的控制潜能,减少害虫发生的可能性;这些措施包括合理安排混作的时空格局,通过轮作进行间断性耕种,对多年生作物采用地面覆盖植被,利用不同品种以提高作物的遗传多样性,等等.在设计农田生物多样性的管理策略时,必须同时考虑当地气候、地理,植被,作物,土壤等因素的变化,因为在特定的生境条件下,这些因素可能增加或减少害虫发生的机会.

  5. The Ecological Functions of Weed Biodiversity in Agroecosystem%农业生态系统杂草多样性保持的生态学功能

    Institute of Scientific and Technical Information of China (English)

    陈欣; 王兆骞; 唐建军

    2000-01-01

    @@ 杂草是农业生态系统中的重要生物组成部分,也是影响农林作物生长和导致产量下降的重要因素之一.过去人们一直努力将杂草从农业生态系统地中清除出去,对杂草的研究往往也更多地注重其危害性和防治途径.

  6. Effect of transgenic plants on biodiversity of agroecosystem%转基因植物对农业生物多样性的影响

    Institute of Scientific and Technical Information of China (English)

    聂呈荣; 王建武; 骆世明

    2003-01-01

    论述了近年来转基因植物对农业生态系统生物多样性影响的研究进展.主要在遗传多样性、物种多样性和生态系统多样性3个层次上予以评述,包括转基因植物对作物遗传多样性的影响;转基因植物的外源基因向杂草和近缘野生种转移;转基因抗虫植物对目标害虫的影响,抗除草剂转基因植物对作物和杂草的影响,抗病毒转基因植物对病毒的影响;转基因植物对非目标生物的影响,对土壤生态系统的影响等.

  7. Budgeting of major nutrients and the mitigation options for nutrient mining in semi-arid tropical agro-ecosystem of Tamil Nadu, India using NUTMON model.

    Science.gov (United States)

    Surendran, U; Rama Subramoniam, S; Raja, P; Kumar, V; Murugappan, V

    2016-04-01

    Mining of nutrients from soil is a major problem in developing countries causing soil degradation and threaten long-term food production. The present study attempts to apply NUTrient MONitoring (NUTMON) model for carrying out nutrient budgeting to assess the stocks and flows of nitrogen (N), phosphorus (P), and potassium (K) in defined geographical unit based on the inputs, viz., mineral fertilizers, manures, atmospheric deposition, and sedimentation, and outputs, viz., harvested crop produces, residues, leaching, denitrification, and erosion losses. The study area covers Coimbatore and Erode Districts, which are potential agricultural areas in western agro-ecological zone of Tamil Nadu, India. The calculated nutrient balances for both the districts at district scale, using NUTMON methodology, were negative for nitrogen (N -3.3 and -10.1 kg ha(-1)) and potassium (K -58.6 and -9.8 kg ha(-1)) and positive for phosphorus (P +14.5 and 20.5 kg ha(-1)). Soil nutrient pool has to adjust the negative balance of N and K; there will be an expected mining of nutrient from the soil reserve. A strategy was attempted for deriving the fertilizer recommendation using Decision Support System for Integrated Fertilizer Recommendation (DSSIFER) to offset the mining in selected farms. The results showed that when DSSIFER recommended fertilizers are applied to crops, the nutrient balance was positive. NUTMON-Toolbox with DSSIFER would serve the purpose on enhancing soil fertility, productivity, and sustainability. The management options to mitigate nutrient mining with an integrated system approach are also discussed.

  8. Environmental factors associated with the distribution of Anopheles arabiensis and Culex quinquefasciatus in a rice agro-ecosystem in Mwea, Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Mwangangi, Joseph; Shililu, Josephat; Jacob, Benjamin G; Mbogo, Charles; Githure, John; Novak, Robert J

    2008-06-01

    Studies were conducted between May and June, 2006 to investigate the environmental factors affecting the distribution of An. arabiensis Patton and Culex quinquefasciatus Say in Mwea, Kenya. The sampling unit comprised all non-paddy aquatic habitats and ten randomly selected paddies and canals located within a 200 m radius from the periphery of the study site. Thirteen physico-chemical variables were recorded for each sampling site in each sampling occasion and a sample of mosquito larvae and other aquatic invertebrates collected. The non-paddy aquatic habitats identified included pools and marshes. Morphological identification of 1,974 mosquito larvae yielded four species dominated by Cx. quinquefasciatus (73.2%) and An. arabiensis (25.0%). Pools were associated with significantly higher Cx. quinquefasciatus larval abundance and less diversity of other aquatic invertebrates compared with other habitat types. In contrast, the abundance of An. arabiensis did not differ significantly among habitat types. Culex quinquefasciatus habitats had higher water conductivity and exhibited a higher abundance of other aquatic invertebrates than An. arabiensis habitats. Chi-square analysis indicated that the two species were more likely to coexist in the same habitats than would be expected by chance alone. Anopheles arabiensis larvae were positively associated with dissolved oxygen and adults of family Haliplidae and negatively associated with emergent vegetation and Heptageniidae larvae. Culex quinquefasciatus larvae were positively associated with dissolved oxygen, total dissolved solids, Chironomidae larvae, and Microvelidae adults and negatively associated with emergent vegetation. These findings suggest that both biotic and abiotic factors play a significant role in niche partitioning among Cx. quinquefasciatus and An. arabiensis, a factor that should be considered when designing an integrated vector control program.

  9. Dynamics of immature stages of Anopheles arabiensis and other mosquito species (Diptera: Culicidae) in relation to rice cropping in a rice agro-ecosystem in Kenya.

    Science.gov (United States)

    Mwangangi, Joseph; Shililu, Josephat; Muturi, Ephantus; Gu, Weidong; Mbogo, Charles; Kabiru, Ephantus; Jacob, Benjamin; Githure, John; Novak, Robert

    2006-12-01

    We determined changes in species composition and densities of immature stages of Anopheles arabiensis mosquitoes in relation to rice growth cycle in order to generate data for developing larval control strategies in rice ecosystems. Experimental rice paddies (6.3m x 3.15m) exposed to natural colonization of mosquitoes were sampled weekly for two rice growing cycles between February 2004 and March 2005. Overall, 21,325 Anopheles larvae were collected, of which 91.9% were 1st and 2nd instars and 8.1% were 3rd and 4th instars. An. arabiensis was the predominant species (84.1%) with other species, An. pharoensis (13.5%), An. funestus (2.1%), An. coustani (0.3%), and An. maculipalpis (0.1%) accounting for only a small proportion of the anophelines collected. Culex quinquefasciatus (65.7%) was the predominant species among the non-anopheline species. Others species collected included: C. annulioris (9.9%), C. poicilipes (7.3%), C. tigripes (7.2%), C. duttoni (0.6%), Aedes aegypti (5.3%), Ae. cumminsii (3.5%), and Ae. vittatus (0.7%). The densities of the major anopheline species were closely related to rice stage and condition of the rice field. An. arabiensis, the predominant species, was most abundant over a three-week period after transplanting. Low densities of larvae were collected during the late vegetative, reproductive, and ripening phases of rice. An increase in larval density ten days post-transplanting was found to correlate with the application of fertilizer (sulphate of ammonia). Culicine and aedine species densities were significantly higher during the post-harvesting period. Our results suggest that the transplanting stage is favorable for the growth of immature stages of An. arabiensis and provides a narrow window for targeted larval intervention in rice.

  10. Describing Anopheles arabiensis aquatic habitats in two riceland agro-ecosystems in Mwea, Kenya using a negative binomial regression model with a non-homogenous mean.

    Science.gov (United States)

    Jacob, Benjamin G; Griffith, Daniel; Muturi, Ephantus; Caamano, Erick X; Shililu, Josephat; Githure, John I; Novak, Robert J

    2009-01-01

    This research illustrates a geostatistical approach for modeling the spatial distribution patterns of Anopheles arabiensis Patton (Patton) aquatic habitats in two riceland environments. QuickBird 0.61 m data, encompassing the visible bands and the near-infra-red (NIR) band, were selected to synthesize images of An. arabiensis aquatic habitats. These bands and field sampled data were used to determine ecological parameters associated with riceland larval habitat development. SAS was used to calculate univariate statistics, correlations and Poisson regression models. Global autocorrelation statistics were generated in ArcGISfrom georeferenced Anopheles aquatic habitats in the study sites. The geographic distribution of Anopheles gambiae s.l. aquatic habitats in the study sites exhibited weak positive autocorrelation; similar numbers of log-larval count habitats tend to clustered in space. Individual rice land habitat data were further evaluated in terms of their covariations with spatial autocorrelation, by regressing them on candidate spatial filter eigenvectors. Each eigenvector generated from a geographically weighted matrix, for both study sites, revealed a distinctive spatial pattern. The spatial autocorrelation components suggest the presence of roughly 14-30% redundant information in the aquatic habitat larval count samples. Synthetic map pattern variables furnish a method of capturing spatial dependency effects in the mean response term in regression analyses of rice land An. arabiensis aquatic habitat data.

  11. 山东省农业生态价值测算及其贡献%Calculation of the Value of Agroecosystems in Shandong Province

    Institute of Scientific and Technical Information of China (English)

    孙能利; 巩前文; 张俊飚

    2011-01-01

    Agriculture not only has economic value, but also with non-economic values, and estimate the economic value of agricultural non-economic values is focused. This article is divided into the value of agricultural production value and ecological value and ecological value by authoritative measure thinking, Accroding to partial global ecosystem services value evaluation results obtained by Costanza et al. Alone with responses of ecological questionnaires from specialists of China, because the study of Costanza et al also received many severe criticism,such as certain data,there are big deviation of arable land estimate is too low,the wetland and partial higher. Therefore,this paper combined with the formation of Shandong Province for the ecological value of the actual calculation method, measured by official statistics, the actual ecological value of Shandong Province. The results showed that in 2008, Shandong Province, agro-ecological value of 7 058.54 billion yuan worth of reality, is an agricultural economy 2.4 times the value of 3002.65 billion yuan.%农业不仅具有经济价值,同时还具有非经济价值,而估算农业的非经济价值成为学术界研究的热点.本文把农业的价值分为生产产品价值和生态价值,并采用具有权威性的生态价值测算思想,即Costanza等于1997年提出的方法作为估算农业生态价值的方法依据,同时,由于该项研究也受到了不少严厉的批评,如某些数据存在着较在偏差,如对耕地的估计过低,对湿地又偏高等.因此,进一步借鉴谢高地等于2003年针对Costanza等的不足,在参考其可靠的部分成果的同时,基于对我国200位生态学者的问卷调查,制定出我国生态系统生态服务价值的当量因子表.以此表为基础,结合山东省实际形成适用的生态价值测算方法,采用官方统计数据实际测算了山东省农业生态价值.结果发现,2008年山东省农业生态价值的现实值为7058.54亿元,是当年农业经济价值3002.65亿元的2.4倍.

  12. Fitossociologia de comunidades de plantas daninhas em agroecossistema cana-crua Phytosociology of weed community in no-burn sugar cane agroecosystems

    Directory of Open Access Journals (Sweden)

    M.A. Kuva

    2007-09-01

    Full Text Available Objetivou-se neste trabalho estudar a fitossociologia de comunidades de plantas daninhas de canaviais colhidos no sistema mecanizado, sem queima prévia da palha, e a similaridade entre talhões quanto à composição de espécies. Os levantamentos foram realizados em 28 talhões comerciais na região de Ribeirão Preto-SP. Em cada talhão foram demarcadas áreas de coleta e avaliação, na proporção de duas por hectare, mantidas sem controle, e que serviram de local para as amostragens de plantas daninhas. As amostragens foram feitas com quadrados vazados (0,5 x 0,5 m, lançados aleatoriamente duas vezes em cada uma das áreas. Essas amostragens foram realizadas determinando-se a densidade e a biomassa específica aos 120 dias após o corte da cana. Cyperus rotundus foi a principal espécie, destacando-se quanto aos valores de importância relativa (IR. As plantas dicotiledôneas anuais de propagação por sementes também se destacaram, dentre as quais diversas espécies das famílias Euphorbiaceae e Convolvulaceae. Em contrapartida, as gramíneas tradicionais de áreas de cana colhida queimada tiveram pouco destaque. O índice de Shannon (H de diversidade de espécies das comunidades variou de 0 a 1,61, e o índice de similaridade entre os talhões (S foi muito variável. A maioria das espécies ou grupo de espécies apresentou padrão agregado (V/m > 1,00, com valores relativamente altos de índice de agregação (V/m. Entretanto, na maioria dos casos, Cyperus rotundus e as Convolvulaceas apresentaram os maiores índices.A study was carried out in northeastern São Paulo, Brazil to evaluate the similarity between species composition and phytosociological index in weed communities of no-burn sugar cane crop harvest at different times and number of cut-cycles. Assessments were carried out in twenty-eight sugar cane plots in the Ribeirao Preto-SP region. In each plot, collection and evaluation areas were established, two per hectare, kept without control and used as weed sampling sites. The samplings were made using squares (0.5 x 0.5 m, randomly cast twice in each area. Weed density and biomass were evaluated per species 120 days after sugar cane harvesting. The phytosociological studies showed that Cyperus rotundus presented the highest values of relative density, dominance, frequency and relative importance index. The seed-propagated dycot plants also presented high values for phytosociological index, mainly the species belonging to the families Euphorbiaceae and Convolvulaceae. On the other hand, the grass weeds, traditionally found in burned sugar cane areas, had very little relevance under the no-burn system. The diversity index (Shannon - H varied from 0 to 1.61 and the similarity index(S was low, except when groups of weeds were compared. The majority of the weed populations showed geographic distribution in match pattern. Areas with high infestation of C. rotundus and/or Convolvulaceae species showed the highest aggregation index.

  13. A Conceptual Framework for the Assessment of Multiple Functions of Agro-Ecosystems: A Case Study of Tras-os-Montes Olive Groves

    Science.gov (United States)

    Fleskens, Luuk; Duarte, Filomena; Eicher, Irmgard

    2009-01-01

    Multifunctionality in agriculture has received a lot of attention the last decade from researchers and policy-makers alike, perhaps most notably evidenced by the important changes made to the EU's Common Agricultural Policy. While the concept has been embraced by environmentalists envisioning positive impulses for decoupling and a range of local…

  14. Do bird assemblages predict susceptibility by e-waste pollution? A comparative study based on species- and guild-dependent responses in China agroecosystems.

    Science.gov (United States)

    Zhang, Qiang; Wu, Jiangping; Sun, Yuxin; Zhang, Min; Mai, Bixian; Mo, Ling; Lee, Tien Ming; Zou, Fasheng

    2015-01-01

    Indirect effects of electronic waste (e-waste) have been proposed as a causal factor in the decline of bird populations, but analyses of the severity impacts on community assembly are currently lacking. To explore how population abundance/species diversity are influenced, and which functional traits are important in determining e-waste susceptibility, here we surveyed breeding and overwintering birds with a hierarchically nested sampling design, and used linear mixed models to analyze changes in bird assemblages along an exposure gradient in South China. Total bird abundance and species diversity decreased with e-waste severity (exposed e-waste polluted sites. A high pairwise similarity between exposed and surrounding sites indicates a diffuse effect of pollutants on the species assembly at local scale. We show that sensitivity to e-waste severity varies substantially across functional guild, with the prevalence of woodland insectivorous and grassland specialists declining, while some open farmland generalists such as arboreal frugivores, and terrestrial granivores were also rare. By contrast, the response of waterbirds, omnivorous and non-breeding visitors seem to be tolerable to a wide range of pollution so far. These findings underscore that improper e-waste dismantling results in a severe decline of bird diversity, and the different bird assemblages on polluted and natural farmlands imply species- and guild-dependent susceptibility with functional traits. Moreover, a better understanding of the impact of e-waste with different pollution levels, combined multiple pollutants, and in a food-web context on bird is required in future.

  15. Taxonomy and distribution of phenazine-1-carboxylic acid-producing Pseudomonas spp. in the dryland agroecosystem of the Inland Pacific Northwest

    Science.gov (United States)

    Five distinct phenazine-producing Pseudomonas species were found, two of which were provisionally ascribed as new species. Agroclimatic zone and the soil silt content were found to affect the distribution of the different species. This study clarifies the classification of these important plant bene...

  16. 耕作侵蚀及其农业环境意义%TILLAGE TRANSLOCATION AND TILLAGE EROSION PROCESSES AND THEIR TMPLICATIONS FOR AGRO-ECOSYSTEMS

    Institute of Scientific and Technical Information of China (English)

    李勇; 张建辉; 罗大卫; 张建国

    2000-01-01

    2l世纪来临之际,耕作研究和耕作习惯将发生重大变化。这一革命性变化的驱动力是人们对耕作位移与耕作侵蚀及其农业持续性和环境保护的日益了解和认识。耕作位移是耕作活动造成的土壤移动。因受耕作工具的设计、操作、景观地形和土壤性质等因素的影响,耕作位移在景观内变异很大。耕作位移在景观内的变化导致净土壤重新分配,即耕作侵蚀。典型的情况是耕作连续地导致土壤顺坡移动,造成土壤在坡上部严重流失,而在坡下部堆积。本文描述了耕作位移和耕作侵蚀过程,概括了其最新研究进展,阐述了耕作侵蚀对作物生产力和温室效应等的农业环境意义,提出了土壤侵蚀研究者面临的挑战和机遇。%As we begin the 21st century tillage research and practices will take significant new directions. This revolution will be driven by a growing awareness and understanding of the processes of tillage translocation and tillage erosion and of their implications for agricultural sustainability and environmental protection. Tillage translocation is the resultant displacement of soil by tillage. Soil can be moved meters by a single pass of tillage. The translocation of soil by tillage varies greatly within landscapes as a result of several factors; these include the design and operation of tillage implements and the topographic and soil properties of landscapes. The consequence of this variation in translocation is net soil redistribution within landscapes, i.e. tillage erosion. Typically, tillage results in the progressive downslope movement of soil, causing severe soil loss on upper slope positions and accumulation in lower slope positions. Tillage translocation and tillage erosion processes are described. An overview of the research to date is presented. A broad range of agri-anvironmental implications is examined including: crop productivity and greenhouse gas emission. Challenges and opportunities for tillage researchers are identified.

  17. N2O and CH4 emissions from a fallow-wheat rotation with low N input in conservation and conventional tillage under a Mediterranean agroecosystem.

    Science.gov (United States)

    Tellez-Rio, Angela; García-Marco, Sonia; Navas, Mariela; López-Solanilla, Emilia; Tenorio, Jose Luis; Vallejo, Antonio

    2015-03-01

    Conservation agriculture that includes no tillage (NT) or minimum tillage (MT) and crop rotation is an effective practice to increase soil organic matter in Mediterranean semiarid agrosystems. But the impact of these agricultural practices on greenhouse gases (GHGs), such as nitrous oxide (N2O) and methane (CH4), is variable depending mainly on soil structure and short/long-term tillage. The main objective of this study was to assess the long-term effect of three tillage systems (NT, MT and conventional tillage (CT)) and land-covers (fallow/wheat) on the emissions of N2O and CH4 in a low N input agricultural system during one year. This was achieved by measuring crop yields, soil mineral N and dissolved organic C contents, and fluxes of N2O and CH4. Total cumulative N2O emissions were not significantly different (P>0.05) among the tillage systems or between fallow and wheat. The only difference was produced in spring, when N2O emissions were significantly higher (Ptillage systems, in spite of the higher DOC content maintained in the topsoil of NT. This could be due to the similar denitrifier densities, targeted by nirK copy numbers at that time. Cumulative CH4 fluxes resulted in small net uptake for all treatments, and no significant differences were found among tillage systems or between fallow and wheat land-covers. These results suggest that under a coarse-textured soil in low N agricultural systems, the impact of tillage on GHG is very low and that the fallow cycle within a crop rotation is not a useful strategy to reduce GHG emissions.

  18. Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xi, E-mail: icy124@hotmail.com [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan); Toma, Yo [Faculty of Agriculture, Ehime University, 3-5-7, Tarumi, Matsuyama 790-8566, Ehime (Japan); Yeluripati, Jagadeesh [The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland (United Kingdom); Iwasaki, Shinya [Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan); Bellingrath-Kimura, Sonoko D. [Leibniz Centre for Agricultural Landscape Research, Institute of Land Use Systems (Germany); Jones, Edward O. [Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London (United Kingdom); Hatano, Ryusuke [Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan)

    2016-06-01

    Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959–2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from − 1.26 Mg C ha{sup −1} yr{sup −1} in 1959–0.26 Mg C ha{sup −1} yr{sup −1} in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959–2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. - Highlights: • We compared C stocks change by two methods: (i) net biome productivity (NBP) and (ii) soil inventory. • Variation in net primary productivity (NPP), plant C input, NBP can be predicted by climate conditions. • NBP decreased in upland and paddy fields under the recent C input scenario. • In the case of land use change, the regional C pools slowly start to build up. • There is no significant difference in two methods (NBP & soil inventory).

  19. Use of video surveillance to measure the influences of habitat management and landscape composition on pollinator visitation and pollen deposition in pumpkin (Cucurbita pepo) agroecosystems.

    Science.gov (United States)

    Phillips, Benjamin W; Gardiner, Mary M

    2015-01-01

    Pumpkin (Cucurbita pepo) production relies on insect-mediated pollination, which is provided by managed and wild pollinators. The goals of this study were to measure the visitation frequency, longevity and temporal activity patterns of pumpkin pollinators and to determine if local habitat management and landscape composition affected this pollination service. We used video surveillance to monitor bee acitivty within male and female pumpkin flowers in 2011 and 2012 across a pollination window of 0600-1200 h. We also quantified the amount of pollen deposited in female flowers across this time period. In 2011, A. mellifera made significantly more floral visits than other bees, and in 2012 Bombus spp. was the dominant pumpkin pollinator. We found variation in visitation among male and female pumpkin flowers, with A. mellifera visiting female flowers more often and spending longer per visit within them than male flowers in both 2011 and 2012. The squash bee P. pruinosa visited male flowers more frequently in 2012, but individuals spent equal time in both flower sexes. We did not find variation in the timing of flower visitation among species across the observed pollination window. In both 2011 and 2012 we found that the majority of pollen deposition occurred within the first two hours (0600-0800 h) of observation; there was no difference between the pollen deposited during this two-hour period and full pollination window (0600-1200 h). Local additions of sweet alyssum floral strips or a field buffer strip of native wildflowers did not have an effect on the foraging activity of bees or pollen deposition. However, semi-natural and urban habitats in the surrounding landscape were positively correlated with the frequency of flower visitation by wild pollinators and the amount of pollen deposited within female flowers.

  20. Seasonal dynamics of CO2 efflux in soils amended with composted and thermally-dried sludge as affected by soil tillage systems in a semi-arid agroecosystem

    Science.gov (United States)

    García-Gil, Juan Carlos; Soler-Rovira, Pedro; López-de-Sa, Esther G.; Polo, Alfredo

    2014-05-01

    In semi-arid agricultural soils, seasonal dynamic of soil CO2 efflux (SCE) is highly variable. Based on soil respiration measurements the effects of different management systems (moldboard plowing, chisel and no-tillage) and the application of composted sludge (CS) and thermally-dried sewage sludge (TSS) was investigated in a long-term field experiment (28 years) conducted on a sandy-loam soil at the experimental station 'La Higueruela' (40o 03'N, 4o 24'W). Both organic amendments were applied at a rate of 30 Mg ha-1 prior to tillage practices. Unamended soils were used as control for each tillage system. SCE was moderate in late spring (2.2-11.8 μmol CO2 m-2 s-1) when amendments were applied and tillage was performed, markedly decreased in summer (0.4-3.2 μmol CO2 m-2 s-1), following a moderate increase in autumn (3.4-14.1 μmol CO2 m-2 s-1), rising sharply in October (5.6-39.8 μmol CO2 m-2 s-1 ). In winter, SCE was low (0.6-6.5 μmol CO2 m-2 s-1). In general, SCE was greater in chisel and moldboard tilled soils, and in CS and particularly TSS-amended soils, due to the addition of labile C with these amendments, meanwhile no-tillage soils exhibited smaller increases in C efflux throughout the seasons. Soil temperature controlled the seasonal variations of SCE. In summer, when drought occurs, a general decrease of SCE was observed due to a deficit in soil water content. After drought period SCE jumped to high values in response to rain events ('Birch effect') that changed soil moisture conditions. Soil drying in summer and rewetting in autumn may promotes some changes on the structure of soil microbial community, affecting associated metabolic processes, and enhancing a rapid mineralization of water-soluble organic C compounds and/or dead microbial biomass that acts as an energy source for soil microorganisms. To assess the effects of tillage and amendments on SCE, Q10 values were calculated. Data were grouped into three groups according to soil moisture (0.03-0.10 m3m-3, 0-11-0.21 m3m-3, 0.22-0.30 m3m-3). In general, Q10 values were lower at elevated temperatures when soil moisture contents decreased, confirming that SCE is less sensitive to soil temperature during drought periods. Q10 values were higher in moldboard and chisel tilled soils, possibly due to the incorporation of residues into soil and the increase of soil C substrate, meanwhile in no-tillage part of the organic C pools are likely protected from microorganisms by physico-chemical mechanisms. TSS-amended soils exhibited higher Q10 values than CS, pointing that the biochemical lability of the organic C added with amendments exerts an influence on SCE. Acknowledgements: this research was supported by the Spanish CICYT, Project no. CTM2011-25557.

  1. Net Mineralization Response to Fertilizer Application and Site-Specific Setting in a No-Till Dryland Wheat Agroecosystem in the Pacific Northwest (USA)

    Science.gov (United States)

    Bruner, Emily A.; Brown, David J.; Carpenter-Boggs, Lynn

    2015-04-01

    Application of nitrogen (N) fertilizers is pivotal to maintaining agricultural productivity. Nutrient management is typically guided by a combined assessment of crop yield requirements, residual soil inorganic N concentration, and predicted N supply from organic matter. However, laboratory assays employed to forecast mineralization potential do not reflect in situ processes occurring in soils, processes that can vary spatially within a field. Furthermore, fertilizer application alters biogeochemical cycles through a variety of mechanisms including priming effects and microbial community alterations. This study investigates in-situ ammonification/nitrification rates utilizing mineralization cores as part of a five-year Site-Specific Climate-Friendly Farming (SCF) project. In-depth accounting of nitrate and ammonium production and flux was possible via a six bag mixed-bed ion exchange resin system. Soil cores (7.5 cm diameter by 15 cm deep) were isolated from the surrounding soil by three resin bags sealed in the top and bottom of individual plastic cylinders. Fifteen locations were selected across a commercial direct-seed wheat field based on statistical clustering of primary and secondary topographic variables. In each location surface soil-resin cores were installed in fertilized and unfertilized plots immediately after spring planting and removed before harvest. In situ ammonification/nitrification rates will be analyzed as a function of both fertilizer application and site-specific environmental characteristics as determined from soil moisture monitoring, soil characterization, and crop analysis at each measurement location. This site-specific information on N transformations and availability can then be used to guide site-specific crop management.

  2. Pesticide residue concentration in soil following conventional and Low-Input Crop Management in a Mediterranean agro-ecosystem, in Central Greece.

    Science.gov (United States)

    Karasali, Helen; Marousopoulou, Anna; Machera, Kyriaki

    2016-01-15

    The present study was focused on the comparative evaluation of pesticide residues, determined in soil samples from Kopaida region, Greece before and after the implementation of Low-Input Crop Management (LCM) protocols. LCM has been suggested as an environmental friendly plant protection approach to be applied on crops growing in vulnerable to pollution ecosystems, with special focus on the site specific problems. In the case of the specific pilot area, the vulnerability was mainly related to the pollution of water bodies from agrochemicals attributed to diffuse pollution primarily from herbicides and secondarily from insecticides. A total of sixty-six soil samples, were collected and analyzed during a three-year monitoring study and the results of the determined pesticide residues were considered for the impact evaluation of applied plant protection methodology. The LCM was developed and applied in the main crops growing in the pilot area i.e. cotton, maize and industrial tomato. Herbicides active ingredients such as ethalfluralin, trifluralin, pendimethalin, S-metolachlor and fluometuron were detected in most samples at various concentrations. Ethalfluralin, which was the active ingredient present in the majority of the samples ranged from 0.01 μg g(-1) to 0.26 μg g(-1) soil dry weight. However, the amount of herbicides measured after the implementation of LCM for two cropping periods, was reduced by more than 75% in all cases. The method of analysis was based on the simultaneous extraction of the target compounds by mechanical shaking, followed by liquid chromatography mass spectrometric and gas chromatography electron capture (LC-MS/MS and GC-ECD) analysis.

  3. Intercropping with Shrub Species That Display a ‘Steady-State’ Flowering Phenology as a Strategy for Biodiversity Conservation in Tropical Agroecosystems

    Science.gov (United States)

    Peters, Valerie E.

    2014-01-01

    Animal species in the Neotropics have evolved under a lower spatiotemporal patchiness of food resources compared to the other tropical regions. Although plant species with a steady-state flowering/fruiting phenology are rare, they provide predictable food resources and therefore may play a pivotal role in animal community structure and diversity. I experimentally planted a supplemental patch of a shrub species with a steady-state flowering/fruiting phenology, Hamelia patens Jacq., into coffee agroforests to evaluate the contribution of this unique phenology to the structure and diversity of the flower-visiting community. After accounting for the higher abundance of captured animals in the coffee agroforests with the supplemental floral resources, species richness was 21% higher overall in the flower-visiting community in these agroforests compared to control agroforests. Coffee agroforests with the steady-state supplemental floral patch also had 31% more butterfly species, 29% more hummingbird species, 65% more wasps and 85% more bees than control coffee agroforests. The experimental treatment, together with elevation, explained 57% of the variation in community structure of the flower-visiting community. The identification of plant species that can support a high number of animal species, including important ecosystem service providers, is becoming increasingly important for restoration and conservation applications. Throughout the Neotropics plant species with a steady-state flowering/fruiting phenology can be found in all aseasonal forests and thus could be widely tested and suitable species used throughout the tropics to manage for biodiversity and potentially ecosystem services involving beneficial arthropods. PMID:24598826

  4. Long-term effects of irrigation with waste water on soil AM fungi diversity and microbial activities: the implications for agro-ecosystem resilience.

    Directory of Open Access Journals (Sweden)

    Maria del Mar Alguacil

    Full Text Available The effects of irrigation with treated urban wastewater (WW on the arbuscular mycorrhizal fungi (AMF diversity and soil microbial activities were assayed on a long-term basis in a semiarid orange-tree orchard. After 43 years, the soil irrigated with fresh water (FW had higher AMF diversity than soils irrigated with WW. Microbial activities were significantly higher in the soils irrigated with WW than in those irrigated with FW. Therefore, as no negative effects were observed on crop vitality and productivity, it seems that the ecosystem resilience gave rise to the selection of AMF species better able to thrive in soils with higher microbial activity and, thus, to higher soil fertility.

  5. Discussion of "Atmospheric deposition as an important nitrogen load to a typical agro-ecosystem in the Huang-Huai-Hai Plain" by Huang et al. (2016)

    Science.gov (United States)

    Pan, Yuepeng; Xu, Wen; Wentworth, Gregory R.; Tian, Shili

    2017-03-01

    In a recent publication of Atmospheric Environment, Huang et al. (2016) reported nitrogen (N) deposition estimates using the water surrogate surface method. This method may be suitable to evaluate the atmospheric N input to a body of water, wetland or paddy fields rather than dry crop land without sustained waterlogged conditions. Such a method may also result in the potential underestimation of both dry and wet N deposition due to the release of ammonia (NH3) from water evaporation and/or N loss from biological activities, and hence bias the relative contribution of dry deposition to total deposition. Besides the uncertainties regarding the magnitude and pathways of N deposition, the statement by Huang et al. (2016) that "nitrate was the dominant species in N deposition even in cropland" is also questionable. We suggest that reduced species dominate the N deposition in Huang-Huai-Hai Plain (i.e., North China Plain) even in urban and industrial regions due to the abundance of NH3.

  6. Diversidade e distribuição espacial de artrópodes associados ao solo em agroecossistemas Diversity and spatial distribution of ground arthropods in agroecosystems

    Directory of Open Access Journals (Sweden)

    Francisco Jorge Cividanes

    2009-01-01

    Full Text Available O conhecimento da diversidade e distribuição de artrópodes associados ao solo contribui para o desenvolvimento de sistemas agrícolas sustentáveis. O presente estudo foi realizado em Jaboticabal (SP, durante o período de fevereiro a abril de 2004. O objetivo foi analisar a comunidade de Carabidae, Staphylinidae, Formicidae e Araneae através de índices faunísticos e determinar a distribuição espacial e a interação interespecífica de espécies predominantes em soja (Glycine max (L. Merr., milho (Zea mays L. e seringueira (Hevea brasiliensis Muell. Arg.. Os artrópodes foram amostrados com armadilhas de solo distribuídas a cada 10 m em dois transectos de 210 m de comprimento, que atravessaram o seringal e avançaram 60 m no interior das culturas. A fauna foi caracterizada pelos índices de diversidade de Shannon-Wiener, de equitabilidade e de similaridade de Morisita. As diferenças entre a ocorrência das espécies predominantes nos hábitats foram determinadas por análise de variância e a interação interespecífica por correlação de Pearson. A soja e o milho cultivados em sistema de plantio direto propiciaram comunidades de carabídeos, formigas e aranhas mais bem estruturadas que o seringal. Entre as 88 espécies capturadas, 20 espécies foram predominantes cuja distribuição espacial mostrou que Odontocheila nodicornis (Dejean, Glenus chrysis Gravenhorst, Castianeira sp. e oito espécies de formigas foram mais abundantes no seringal em comparação às culturas de soja e do milho. A abundância dos carabídeos Calosoma granulatum Perty e O. nodicornis diminuiu conforme aumentou a densidade dos formicídeos Pheidole sp.1 e Odontomachus chelifer Latreille respectivamente.The knowledge of the diversity and distribution of ground arthropods contributes for the development of sustainable agricultural systems. This work was carried out at the Paulista State University, Jaboticabal campus, State of São Paulo, Brazil, during the period from February to April 2004. The objective was to analyse the community of Carabidae, Staphylinidae, Formicidae e Araneae through faunistic indexes, to determine the spatial distribution and interespecific interactions of predominant species in soybean (Glycine max (L. Merr., corn (Zea mays L. and rubber tree (Hevea brasiliensis Muell. Arg.. The arthropods were sampled by pitfall traps distributed each 10 m in two transects of 210 m which crossed the rubber trees and advancing 60 m in the crop lines. The fauna was characterized by Shannon-Wiener diversity index, evenness and Morisita similarity index. The differences among the occurrence of predominant species in the habitats were determined by variance analysis, and the interespecific interaction by Pearson correlation. The soybean and corn under no-tillage system provided better structured carabids, ants and spiders communities than the rubber trees. Among 88 captured species, 20 species were predominant and the spatial distribution of them showed that Odontocheila nodicornis (Dejean, Glenus chrysis Gravenhorst, Castianeira sp. and eight ant species were more abundant in the rubber tree compared to soybean and corn. The abundance of the carabids Calosoma granulatum Perty and O. nodicornis decreased with increased density of the formicids Pheidole sp.1 and Odontomachus chelifer Latreille, respectively.

  7. Differences in carbon density and soil CH4/N2O flux among remnant and agro-ecosystems established since European settlement in the Mornington Peninsula, Australia.

    Science.gov (United States)

    Livesley, Stephen J; Idczak, Daniel; Fest, Benedikt J

    2013-11-01

    National and regional C emissions from historical land use change (LUC) and fossil fuel use are proposed as a basis to ascribe 'burden-sharing' for global emission reduction targets. Changes in non-CO2 greenhouse gas emissions as a result of LUC have not been considered, but may be considerable. We measured soil-atmosphere exchange of methane (CH4) and nitrous oxide (N2O) in remnant forest, pasture and viticulture systems in four seasons, as well as differences in soil C density and the C density of remnant forest vegetation. This approach enabled comparative assessment of likely changes in ecosystem C density and soil non-CO2 greenhouse gas exchange along a LUC continuum since European settlement. Soil CH4 uptake was moderate in forest soil (-27 μg C m(-2) h(-1)), and significantly different to occasionally large CH4 emissions from viticulture and pasture soils. Soil N2O emissions were small and did not significantly differ. Soil C density increased significantly with conversion from forest (5 kg m(-2)) to pasture (9 kg m(-2)), and remained high in viticulture. However, there was a net decrease in ecosystem C density with forest conversion to pasture. Concurrently, net soil non-CO2 emissions (CH4 and N2O combined) increased with conversion from forest to pasture. Since European settlement 170 years ago, it was estimated ~8114 Gg CO2-e has been released from changes in ecosystem C density in the Mornington Peninsula, whereas ~383 Gg CO2-e may have been released from changes in soil non-CO2 exchange processes. Principally, a switch from soil CH4 uptake to soil CH4 emission after forest clearing to agro-pastoral systems provided this further ~5% contribution to the historical landscape CO2-e source strength. Conserving and restoring remnant forests and establishing new tree-based systems will enhance landscape C density. Similarly, minimising anaerobic, wet conditions in pasture/viticulture soils will help reduce non-CO2 greenhouse gas emissions.

  8. Using fourier-transform mid-infrared spectroscopy to distinguish soil organic matter composition dynamics in aggregate fractions of two agroecosystems

    Science.gov (United States)

    The relationship between soil organic carbon (SOC) content and quality of SOC as impacted by land management is not well understood and may influence long-term storage of SOC. To better understand the potential for SOC storage in specific aggregate pools (i.e. physically protected intra-aggregate C)...

  9. The potential of community fish refuges (CFRs) in rice field agro-ecosystems for improving food and nutrition security in the Tonle Sap region

    OpenAIRE

    Brooks, A.; Sieu, C.

    2016-01-01

    The fisheries sector in Cambodia contributes 8%–12% to national GDP and 25% - 30% to agricultural GDP, with an estimated 4.5 million people involved in fishing and associated trades. Fish and other aquatic animals are important food sources, contributing an estimated national average of 60% - 70% of total animal protein intake. Of the 2013 total fish production, 550,000 metric tons were harvested from freshwater habitats, of which rice field fisheries and small-scale family fisheries contribu...

  10. Background antibiotic resistance patterns in antibiotic-free pastured poultry production

    Science.gov (United States)

    Antibiotic resistance (AR) is a significant public health issue, and agroecosystems are often viewed as major environmental sources of antibiotic resistant foodborne pathogens. While the use of antibiotics in agroecosystems can potentially increase AR, appropriate background resistance levels in th...

  11. Exploring land use scenarios by long-term simulation of soil organic matter in central Argentina

    NARCIS (Netherlands)

    Tittonell, P.A.; Grazia, de J.; Hek, de S.; Bricchi, E.

    2006-01-01

    Frequently, agriculture intensification by means of high-input technologies and agroecosystem simplification led to unsustainable farming systems. Increasing spatial-temporal diversity in agroecosystems has been shown as a promising alternative for restoring degraded land. A methodological approach

  12. The impact of biological invasion on biodiversity and grassland agroecosystem%生物入侵对生物多样性以及草地农业生态系统的影响

    Institute of Scientific and Technical Information of China (English)

    王海波; 孙娟; 玉永雄

    2007-01-01

    从生物入侵的原理、生物多样性的概念以及草地农业生态系统的健康评价方面对三者的内在生态关系进行了分析和探讨,以期达到合理引入外来物种、保持生物多样性和稳定草地农业生态系统的三重效应.并在此基础之上提出如何保持生态平衡,使草地农业生态系统能够达到经济、社会和生态三盈,做到可持续的发展.

  13. Utilization and conservation of biodiversity in agroecosystem of China after entering WTO%浙江省农业生物多样性的保护、利用与WTO

    Institute of Scientific and Technical Information of China (English)

    薛玉中; 唐建军

    2001-01-01

    本文论述了生物多样性的重要作用及保护现状,分析了浙江省农业生物多样性的特点,并针对我国加入WTO后,面对"农产品市场萎缩"、"绿色壁垒"、"生物入侵"等新问题、新挑战,结合实例,提出了浙江省加强农业生物多样性保护、利用,提高农产品国际市场竞争力,促进效益农业、精品农业发展,维护生态安全的措施、对策.

  14. The Impacts of Agricultural Activities on Biodiversity in Agroecosystems%农业活动对农田生态系统物种多样性的影响

    Institute of Scientific and Technical Information of China (English)

    姜俊红; 金玲; 朱朝荣; 路玉杰

    2005-01-01

    农业活动如化肥、农药、地膜的使用、高产品种的推广、节水灌溉技术的应用等,所导致的生境条件的变化和农田景观结构的不合理是影响农田生态系统物种多样性的重要原因.鉴于此,提出了保护农田生态系统物种多样性的几点建议:①建立可持续的生态农业;②进行合理的农田生态规划;③合理的混合种植不同作物,打破单一的种植结构.

  15. Multiscale ecology of agroecosystems is an emerging research field that can provide a stronger theoretical background for the integrated pest management. Reply to comments on “Multiscale approach to pest insect monitoring: Random walks, pattern formation, synchronization, and networks”

    Science.gov (United States)

    Petrovskii, Sergei; Petrovskaya, Natalia; Bearup, Daniel

    2014-09-01

    We would like to thank all commentators for their insightful and thought-provoking commentaries [1-4] that also helped to further broaden the scope of our review [5] as well as to extend the list of references. We very much appreciate the positive comments on the relevance, timeliness and comprehensiveness of our work.

  16. Coupling a high resolution soil erosion model with an agro-ecosystem model of SOC dynamics. An approach to assess the potential environmental effect of the new Common Agricultural Policy on soil degradation

    Science.gov (United States)

    Borrelli, Pasqualle; Paustian, Keith; Panagos, Panos; Jones, Arwyn; Schütt, Brigitta; Lugato, Emanuele

    2016-04-01

    At the European Union level, the main mechanisms to promote a more sustainable and environmentally friendly agriculture was introduced by the Common Agricultural Policy (CAP) reform in 2003, through the Cross-compliance. According to this new regulation, the farmer support payments were regulated with respect to environmental, animal welfare and food safety standards. This brought to the Good Agricultural and Environmental Conditions (GAEC), firstly established by Council Regulation No. 1782/2003 and subsequently Council Regulation (EC) No 73/2009. The prevention of soil erosion and maintenance of soil organic matter were two of GAEC requirements, which each Member State was obliged to address through national standards such as: i) minimal soil cover maintenance (GAEC 4); ii) minimum land management reflecting site specific conditions to limit soil loss (GAEC 5) and iii) maintenance of soil organic matter level through appropriate practices including ban on burning arable stubbles (GAEC 6). Although Member States are required to verify whether the farmers are compliant with the regulations (Cross-compliance), the environmental effect of Good Agricultural and Environmental Conditions (GAEC) applications on erosion and carbon budgets are still little known and studied. To investigate the potential impacts of the GAEC, we coupled a high resolution erosion model based on Revised Universal Soil Loss Equation (RUSLE) with the CENTURY biogeochemical model (Land Use Policy, 50, 408-421; 2016). The Italian arable land was selected as a study area, since it is well-known to be highly sensitive to soil erosion. Multi scenario modelling approach was undertaken, i.e., i) a baseline scenario without scenario excluding GAEC (pre 2003 period); ii) a present scenario including the current GAEC standards (post 2003 period), and iii) a technical potential scenario assuming that the GAEC standards were applied to the entire Italian arable land. The results show a 10.8% decrease, from 8.33 Mg ha-1 yr-1 to 7.43 Mg ha-1 yr-1, in soil loss potential due to the adoption of the GAEC conservation practices (with respect to the baseline scenario). The technical potential scenario shows a 50.1% decrease in the soil loss potential (soil loss 4.1 Mg ha-1 yr-1). With regard to the soil organic carbon (SOC), the GAEC application in the current scenario shown an overall soil organic carbon (SOC) gains, with about 17% of the SOC variation related to avoided SOC transport by sediment erosion. The technical potential scenario suggests a potential gain up to 23.3 Mt of C by 2020 with the full GAEC application.

  17. Trend Analysis of Agro-ecosystem Development in Huaihua Based on Energy%基于能值的怀化市农业生态系统发展趋势分析

    Institute of Scientific and Technical Information of China (English)

    谭伟文; 礼章

    2014-01-01

    The tendency of energy input and output ,economic benefit and sustainability of agro‐ecosystem in Huaihua from 1980 to 2005 has been analyzed .The results show that the total energy input has the downtrend since 2000 ,and the energy output has 2 .7 percent annual grow th rate from 1980 to 2005 ,espe‐cially the ratio of animal husbandry and animal breeding husbandry reaches 6 .7 percent .In the economic benefits ,the net energy yield ratio rise from 1 .08 in 1980 to 2 .07 in 2005 .The pressure of environment keep the appropriate level and strong sustainability .In the agricultural economy development ,the input and output efficiency should be further improve ,and the animal husbandry and animal breeding husbandry should be key supported ,the agricultural modernization should be speed propulsion as well .%通过对1980—2005年怀化市农业生态系统的能值投入、产出、经济效益及可持续性进行趋势分析,弥补了只通过单个年度对农业生态系统进行能值研究的不足.分析结果表明,怀化市农业生态系统的总能值投入在2000年后呈下降趋势;总能值产出1980—2005年的25年中,年均增长约2.7%,其中畜牧及饲养业1990—2000年的年均增长比率达6.7%.在经济效益方面,怀化市农业生态系统净能值产出率由1980年的1.08上升到2005年的2.07.怀化市农业生态系统环境压力一直保持在合适水平,可持续性较强.怀化市在发展农业经济中,应进一步提高投入产出效益,重点扶持和发展以畜牧和饲养业为代表的优势产业,同时应加大农业现代化的推进.

  18. N{sub 2}O and CH{sub 4} emissions from a fallow–wheat rotation with low N input in conservation and conventional tillage under a Mediterranean agroecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Tellez-Rio, Angela, E-mail: angela.tellez@upm.es [E.T.S.I. Agrónomos, Technical University of Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); García-Marco, Sonia [E.T.S.I. Agrónomos, Technical University of Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Navas, Mariela; López-Solanilla, Emilia [E.T.S.I. Agrónomos, Technical University of Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Centro de Biotecnología y Genómica de Plantas UPM-INIA. Dpto Biotecnología. E.T.S.I. Agrónomos. Technical University of Madrid. Campus Montegancedo, UPM. Autovía M-40, Salida 38 N, 36S. 28223 Pozuelo de Alarcón. Madrid (Spain); Tenorio, Jose Luis [Dpto. de Medio Ambiente, INIA. Ctra. de La Coruña km. 7.5, 28040 Madrid (Spain); Vallejo, Antonio [E.T.S.I. Agrónomos, Technical University of Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2015-03-01

    Conservation agriculture that includes no tillage (NT) or minimum tillage (MT) and crop rotation is an effective practice to increase soil organic matter in Mediterranean semiarid agrosystems. But the impact of these agricultural practices on greenhouse gases (GHGs), such as nitrous oxide (N{sub 2}O) and methane (CH{sub 4}), is variable depending mainly on soil structure and short/long-term tillage. The main objective of this study was to assess the long-term effect of three tillage systems (NT, MT and conventional tillage (CT)) and land-covers (fallow/wheat) on the emissions of N{sub 2}O and CH{sub 4} in a low N input agricultural system during one year. This was achieved by measuring crop yields, soil mineral N and dissolved organic C contents, and fluxes of N{sub 2}O and CH{sub 4}. Total cumulative N{sub 2}O emissions were not significantly different (P > 0.05) among the tillage systems or between fallow and wheat. The only difference was produced in spring, when N{sub 2}O emissions were significantly higher (P < 0.05) in fallow than in wheat subplots, and NT reduced N{sub 2}O emissions (P < 0.05) compared with MT and CT. Taking into account the water filled pore space (WFPS), both nitrification and denitrification could have occurred during the experimental period. Denitrification capacity in March was similar in all tillage systems, in spite of the higher DOC content maintained in the topsoil of NT. This could be due to the similar denitrifier densities, targeted by nirK copy numbers at that time. Cumulative CH{sub 4} fluxes resulted in small net uptake for all treatments, and no significant differences were found among tillage systems or between fallow and wheat land-covers. These results suggest that under a coarse-textured soil in low N agricultural systems, the impact of tillage on GHG is very low and that the fallow cycle within a crop rotation is not a useful strategy to reduce GHG emissions. - Highlights: • Tillage systems and land-covers with low N input had no effect on total N{sub 2}Ofluxes • No tillage reduced N{sub 2}O fluxes just during spring season • N{sub 2}O fluxes were only greater in fallow than in wheat during spring season • Denitrification capacity and nirK abundance were similar among tillage systems • Cumulative CH{sub 4} fluxes resulted in a low net uptake among tillage systems.

  19. Biological and ecological characterization of two mites (Tetranychus Urticae and Phytoseiulus Persimilis) occurring in some agro-ecosystems; Caratterizzazione biologica ed ecologica di due acari (Tetranichus Urticae e Phytoseiulus Persimilis) interagenti in alcuni ecosistemi agrari

    Energy Technology Data Exchange (ETDEWEB)

    Calvitti, M. [ENEA, Centro Ricerche Casaccia, Roma (Italy). Dip. Innovazione

    1995-12-01

    This work is a brief review of the actual knowledge about biological and ecological characteristics of two species of mites: Tetranychus urticae Koch (Acarina Tetranychidae) (two-spotted spider mite) and the predaceous mite Phytoseiulus persimilis Athias Henriot (Acarina Phytoseiidae). Success obtained in biological control of spider mite, by mass release of P. persimilis, has increased the interest in biological and ecological study of these mites. Particularly, the following biological and ecological aspects of both P. persimilis and T. urticae are hereby discussed: reproductive biology; population dynamics (spider mites outbreaks) and natural regulation of the trophic interaction; feeding behaviour; biological control of two-spotted spider mite by P. persimilis. In this report experimental data obtained in laboratory have been integrated with bibliographic information concerning studies produced in natural conditions.

  20. The net return from animal activity in agro-ecosystems: trading off benefits from ecosystem services against costs from crop damage [v2; ref status: indexed, http://f1000r.es/3c4

    Directory of Open Access Journals (Sweden)

    Gary W Luck

    2014-04-01

    Full Text Available Animals provide benefits to agriculture through the provision of ecosystem services, but also inflict costs such as damaging crops. These benefits and costs are mostly examined independently, rather than comparing the trade-offs of animal activity in the same system and quantifying the net return from beneficial minus detrimental activities. Here, I examine the net return associated with the activity of seed-eating birds in almond orchards by quantifying the economic costs and benefits of bird consumption of almonds. Pre-harvest, the consumption of harvestable almonds by birds cost growers AUD$57.50 ha-1 when averaged across the entire plantation. Post-harvest, the same bird species provide an ecosystem service by removing mummified nuts from trees that growers otherwise need to remove to reduce threats from fungal infection or insect pest infestations. The value of this ecosystem service ranged from AUD$82.50 ha-1–$332.50 ha-1 based on the replacement costs of mechanical or manual removal of mummified nuts, respectively. Hence, bird consumption of almonds yielded a positive net return of AUD$25–$275 ha-1 averaged across the entire plantation. However, bird activity varied spatially resulting in positive net returns occurring primarily at the edges of crops where activity was higher, compared to negative net returns in crop interiors. Moreover, partial mummy nut removal by birds meant that bird activity may only reduce costs to growers rather than replace these costs completely. Similar cost-benefit trade-offs exist across nature, and quantifying net returns can better inform land management decisions such as when to control pests or promote ecosystem service provision.

  1. 荒漠绿洲农业生态系统养分平衡与调控%Balance and control of soil nutrent in agro-ecosystem in the desert oases

    Institute of Scientific and Technical Information of China (English)

    王周琼; 李述刚

    2001-01-01

    通过研究新疆绿洲农业生态系统历年养分平衡演变情况发现,N盈余为- 26.9%~+27.2%,P2O5盈余为188.1%,K2O则亏缺,新绿洲化肥投入已占养分总投入的 74.9%,有机养分投入逐年减少.提出了养分良性循环指数(MN)概念,当前新绿洲MN只有0.128.阐述了人为调控模式施肥制度,其MN可达到0.581,有机氮再循环系数 (H)接近1.为了培肥地力,模式养分平衡要求N盈余在40%以上,以实现绿洲农业生态系统养分良性循环.

  2. The effect of nitrogen and glyphosate on survival and colonisation of perennial grass species in an agro-ecosystem: does the relative importance of survival decrease with competitive ability?

    Science.gov (United States)

    Damgaard, Christian; Strandberg, Beate; Mathiassen, Solvejg K; Kudsk, Per

    2013-01-01

    The ecological success of a plant species is typically described by the observed change in plant abundance or cover, but in order to more fully understand the fundamental plant ecological processes, it is necessary to inspect the underlying processes of survival and colonization and how they are affected by environmental conditions. A general ecological hypothesis on the effect of environmental gradients on demographic parameters is proposed and tested. The hypothesis is that decreasing fitness or competitive ability along an environmental gradient is associated with an increasing importance of survival for regulating the abundance of the species. The tested hypothesis is related to both the stress gradient hypothesis and whether the importance of competition increases along productivity gradients. The combined effect of nitrogen and glyphosate on the survival and colonization probability of two perennial grass species, Festuca ovina and Agrostis capillaris, which are known to differ in their responses to both glyphosate and nitrogen treatments, is calculated using pin-point cover data in permanent frames. We found that the relative importance of survival increased with the level of glyphosate for the glyphosate sensitive A. capillaris and decreased for the glyphosate tolerant F. ovina. Likewise, increasing levels of nitrogen increased the importance of survival for the relative nitrophobic F. ovina. Consequently, the proposed hypothesis was corroborated in this specific study. The proposed method will enable predictions of the effects of agricultural practices on community dynamics in a relatively simple setup eliminating the need to quantify all the interaction among the species in the plant community. The method will be immediately useful for the regulation of non-cultivated buffer strips between agricultural fields and semi-natural and natural biotopes such as hedgerows and waterways.

  3. Soil enzyme activities under long-term tillage and crop rotation systems in subtropical agro-ecosystems Atividade enzimática em solo sob plantio direto e rotações de culturas em agro-ecossistema subtropical

    Directory of Open Access Journals (Sweden)

    Elcio Liborio Balota

    2004-12-01

    Full Text Available Agricultural practices that reduce soil degradation and improve agricultural sustainability are needed particularly for tropical/subtropical soils. No-tillage planting causes minimal soil disturbance and combined with crop rotation may hold potential to meet these goals. Soil enzyme activities can provide information on how soil management is affecting the potential to perform the processes in soils such as decomposition and nutrient cycling. Soil enzyme activities were investigated in a split-plot experiment (3 replications where tillage (no till and conventional was the main plot and crop rotation (soybean/wheat, S/W; maize/wheat, M/W or cotton/wheat, C/W was the subplot. The experiment was established in 1976 in southern Brazil. Soil samples were taken at 0-5, 5-10 and 10-20 cm depths in 1997 and 1998. The 0-5 cm layer under NT system showed increases up 68% for amylase, 90% for cellulase, 219% for arylsulfatase, 46% for acid phosphatase, and 61% for alkaline phosphatase. There were significant correlations of soil enzyme activities with total organic C, and C and N microbial biomass. These results showed that NT increased microbial activity and that soil enzyme activity is a sensitive indicator of alteration soil quality by management.Práticas agrícolas que reduzam a degradação do solo e promovam sustentabilidade são importantes para os agrossistemas tropicais/subtropicais. O plantio direto (PD diminui as perdas de solo e, se combinado com rotação de culturas pode proteger o solo da degradação físico-química provocada pela agricultura intensiva. A atividade enzimática do solo pode fornecer importantes informações de como o manejo do solo está afetando a decomposição da material orgânica e a ciclagem dos nutrientes. Assim, avaliou-se a atividade das enzimas amilase, celulose, arilsulfatase, fosfatase ácida e fosfatase alcalina em um experimento a campo, instalado em 1976 em Londrina, PR, que tem como tratamentos o preparo do solo (plantio direto ou convencional nas parcelas e a rotação de culturas (soja/trigo, milho/trigo e algodão/trigo nas subparcelas. Amostras de solos foram coletadas a 0-5, 5-10 e 10-20 cm de profundidade em 1997 e 1998. Na profundidade de 0-5 cm sob PD, observaram-se aumentos de 68% na atividade da amilase, 90% na celulase, 219% na arilsulfatase, 46% na fosfatase ácida e 61% na fosfatase alcalina. Observaram-se correlações significativas entre a atividade enzimática e o C-orgânico total do solo e o C e N da biomassa microbiana. Esses resultados evidenciam que a atividade enzimática do solo é um indicador sensível de alterações na qualidade do solo, promovidas pelo manejo.

  4. Ecology and behavior of Anopheles arabiensis in relation to agricultural practices in central Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Mwangangi, Joseph M; Beier, John C; Blackshear, Millon; Wauna, James; Sang, Rosemary; Mukabana, Wolfgang R

    2013-09-01

    Ecological changes associated with anthropogenic ecosystem disturbances can influence human risk of exposure to malaria and other vector-borne infectious diseases. This study in Mwea, Kenya, investigated the pattern of insecticide use in irrigated and nonirrigated agroecosystems and association with the density, survival, and blood-feeding behavior of the malaria vector Anopheles arabiensis. The parity rates of adult An. arabiensis from randomly selected houses were determined by examining their ovaries for tracheal distension, and polymerase chain reaction was used to identify the host blood meals. In addition, structured questionnaires were used to generate data on insecticide use. Anopheles arabiensis densities were highest in irrigated rice agroecosystems, intermediate in irrigated French beans agroecosystems, and lowest in the nonirrigated agroecosystem. Anopheles arabiensis adult survivorship was significantly lower in irrigated rice agroecosystems than in irrigated French beans agroecosystems. The human blood index (HBI) was significantly higher in the nonirrigated agroecosystem compared to irrigated agroecosystems. Moreover, there was marked variation in HBI among villages in irrigated agroecosystems with significantly lower HBI in Kangichiri and Mathangauta compared to Kiuria, Karima, and Kangai. The proportion of mosquitoes with mixed blood meals varied among villages ranging from 0.25 in Kangichiri to 0.83 in Kiuria. Sumithion, dimethoate, and alpha cypermethrin were the most commonly used insecticides. The 1st was used mostly in irrigated rice agroecosystems, and the last 2 were used mostly in irrigated French beans agroecosystems. These findings indicate that agricultural practices may influence the ecology and behavior of malaria vectors and ultimately the risk of malaria transmission.

  5. Antibiotic resistance patterns of major zoonotic pathogens from all-natural, antibiotic-free, pasture-raised broiler flocks in the southeastern United States

    Science.gov (United States)

    The use of antibiotics in agroecosystems has been implicated in the rise in antibiotic resistance that can affect environmental, animal, and human health. In order to effectively determine the environmental impact of antibiotic use in agroecosystems, appropriate background levels of antibiotic resi...

  6. Modelling Crop Biocontrol by Wanderer Spiders

    Science.gov (United States)

    Venturino, Ezio; Ghersi, Andrea

    2008-09-01

    We study mathematically the effects some spiders populations have on insects living in and near agroecosystems, where woods and vineyards alternate in the landscape as in the Alta Langa, Piemonte, NW Italy.

  7. Agricultural geophysics: Past/present accomplishments and future advancements

    Science.gov (United States)

    Geophysical methods have become an increasingly valuable tool for application within a variety of agroecosystems. Agricultural geophysics measurements are obtained at a wide range of scales and often exhibit significant variability both temporally and spatially. The three geophysical methods predomi...

  8. The influence of vegetation and landscape structural connectivity on butterflies (Lepidoptera: Papilionoidea and Hesperiidae), Carabids (Coleoptera: Carabidae), Syrphids (Diptera: Syrphidae), and sawflies (Hymenoptera: Symphyta) in Northern Italy farmland

    NARCIS (Netherlands)

    Burgio, G.; Sommaggio, D.; Marini, M.; Chiarucci, A.; Landi, S.; Fabbri, R.; Pesarini, F.; Genghini, M.; Ferrari, R.; Muzzi, E.; Lenteren, van J.C.; Masetti, A.

    2015-01-01

    Landscape structure as well as local vegetation influence biodiversity in agroecosystems. A study was performed to evaluate the effect of floristic diversity, vegetation patterns, and landscape structural connectivity on butterflies (Lepidoptera: Papilionoidea and Hesperiidae), carabids (Coleoptera:

  9. Climate change effects on plant disease: Genomes to ecosystems

    OpenAIRE

    Garrett, Karen A.; Dendy, S.P.; Frank, E.E.; Rouse, M. N.; Travers, S.E.

    2006-01-01

    We have reviewed the potential effects of climate change on plant disease, considering processes within plants as well as larger scale processes. LTRA-4 (Practices and Strategies for Vulnerable Agro-Ecosystems)

  10. The unique genomic landscape surrounding the EPSPS gene in glyphosate resistant Amaranthus palmeri: A repetitive path to resistance

    Science.gov (United States)

    The expanding number and global distributions of herbicide resistant weedy species threaten food, feed, fiber and bioproduct sustainability and agroecosystem longevity. Amongst the most competitive weeds, Amaranthus palmeri S. Wats has rapidly evolved increased resistance to glyphosate primarily th...

  11. Open software tools for eddy covariance flux partitioning

    Science.gov (United States)

    Agro-ecosystem management and assessment will benefit greatly from the development of reliable techniques for partitioning evapotranspiration (ET) into evaporation (E) and transpiration (T). Among other activities, flux partitioning can aid in evaluating consumptive vs. non-consumptive agricultural...

  12. Can foraging behavior of Criollo cattle help increase agricultural production and reduce environmental impacts in the arid Southwest?

    Science.gov (United States)

    The Longterm Agroecosystem Research Network (LTAR) was formed to help the nation’s agricultural systems simultaneously increase production and reduce environmental impacts. Eighteen networked sites are conducting a Common Experiment to understand the environmental and economic problems associated wi...

  13. Early-season flood enhances native biological control agents in Wisconsin cranberry

    Science.gov (United States)

    Biological control is predicated on the concept that crop plants are protected when predators suppress herbivore populations. However, many factors, including concurrent crop protection strategies, may modify the effectiveness of a predator in a given agroecosystem. In Wisconsin commercial cranberry...

  14. 农业生态系统中生物多样性的功能--兼论其保护途径与今后研究方向%Functions of Biodiversity in Agroecosystem-Approaches to Its Conservation and Orientation of Future Research

    Institute of Scientific and Technical Information of China (English)

    陈欣; 王兆骞; 唐建军

    2002-01-01

    重点论述了农业生态系统中生物多样性的功能,其功能主要表现在害虫控制、土壤侵蚀防治、退化环境恢复、消除污染和促进养分循环等方面.探讨了农业生态系统中生物多样性的保护途径及今后应开展的研究重点.

  15. The Health Assessment of Agro-ecosystem in the Typical Agro-pastoral Ecotone:A Case Study in Chifeng City%典型农牧交错区农业生态系统健康测度及其持续利用对策——以赤峰市为例

    Institute of Scientific and Technical Information of China (English)

    谢花林

    2009-01-01

    As a new objective for global management as well as a new method of analyzing ecosystem, ecosystem health is embraced by many researchers with great concerns in the modern ecology. Agricultural ecosystem is an open artificial system and has many output and in put of energy and material. Agricultural ecosystem is different from natural ecosystem. Agricultural ecosystem is an ecosystem controlled and managed by human to satisfy the expectations with regulated system structures and altered industrial scales. The system structure exerts significant influence on the system function. A healthy agricultural ecosystem not only has good ecological environment, reasonable proportions of primary production and secondary production in the agricultural eco-economic system, but also has endurable and stable economic benefit. Agricultural ecosystem health is defined as the capability to avoid "disorder syndrome", withstand stress and meet the requirements of sustainable agricultural production. A healthy agricultural ecosystem can meet human needs without threatening natural resources or even can benefit the natural resources. The aim of healthy agricultural ecosystem is to realize high-yielding, low-input, reasonable farming methods, good stability, resilience and persistence. In this paper, based on the characteristic of agricultural ecosystem in the agricultural and pastoral zone, an index system of agricultural ecosystem assessment is formulated according to the definition of healthy agricultural ecosystem, including the factors of vigor, structure and resilience of agricultural ecosystem. The assessment model is applied to twelve counties in Chifeng region. The evaluation results indicate that the agricultural ecosystem in Hongshan County and Balinyou County is healthy, while that in Keshi-keteng County, Yuanbaoshan County, Aohan County and Songshan County can only be described as critically healthy and the agricultural ecosystems in the other six counties are not healthy. The results generated from the assessment model are basically in accordance with the actual status. Therefore, the index system and model of evaluation are proved to be credible. At last, the suggestions for the sustainable utilization of agricultural ecosystem in the agricultural and pastoral zone are put forward. Adopting the ecosystem health as assessing measure for the agricultural ecosystem can improve the management of agricultural ecosystem.%生态系统健康作为全球管理的新目标,作为分析生态系统的新方法而受到青睐,是现代生态学的研究热点之一.本文根据生态系统健康的内涵和农牧交错带农业生态系统的特点,从活力、组织结构和恢复力3个方面选取18个指标.构建了农牧交错带农业生态系统健康的评价指标体系.在此基础上建立综合评价模型,应用于赤峰12个旗(区、县),得到如下结果:农业生态系统健康状况处在"健康"标准是红山区和巴林右旗;处在"临界健康"标准是克什克腾旗、元宝山区、敖汉旗、松山区;处在"不健康"标准是宁城县、林西县、巴林左旗、喀喇沁旗、阿鲁克尔沁旗、翁牛特旗.评价结果基本上反映了当地农业生态系统的健康状况,说明建立的评价指标体系与模型是可行的.最后提出了农牧交错带农业生态系统持续利用的对策.

  16. CARACTERIZACIÓN Y EVALUACIÓN DE AGROECOSISTEMAS A ESCALA PREDIAL UN ESTUDIO DE CASO: CENTRO AGROPECUARIO COTOVE (SANTA FÉ DE ANTIOQUIA, COLOMBIA CHARACTERIZATION AND EVALUATION OF AGROECOSYSTEMS ON A FARM SCALE. A CASE STUDY: COTOVE FARMING CENTER. ( SANTA FE DE ANTIOQUIA, COLOMBIA

    Directory of Open Access Journals (Sweden)

    Juan Camilo De los Ríos Cardona

    2004-06-01

    Full Text Available Se caracteriza y evalúa el estado, condición y tendencia, de los Agroecosistemas (AE del Centro Agropecuario Cotové de la Universidad Nacional de Colombia, Sede Medellín, mediante la parametrización y análisis de las variadas Receptividad Tecnológica (RT e Intensidad Tecnológica (IT, con base en la propuesta metodológica de Vélez y Gastó (1999, en cuanto a la diversidad de AE y de usos, manejo y acogida tecnológica, dotación en tecnoestructura e hidroestructura, potencial productivo y servicios a la sociedad local regional y nacional. Los resultados muestran que la mayor parte del área del Centro (60,2% tiene RT Alta, la cual admite el establecimiento de Sistemas de Manejo Agrotecnológico (SMA Mecanizados Avanzados, pero solo el 15,72% del área es manejado con este SMA. El 69.3% del área del Centro, principalmente bajo cobertura de pasto para ganadería de pie de cría, es manejada con SMA tradicional. Como producto de la interacción entre RT y los SMA utilizados, se encontraron nueve AE, de los cuales, cinco, que representan el 27,1% del área ( 33,6 ha, se manejan con tecnologías adecuadas a sus condiciones biofísicas o de receptividad tecnológica (IT Adecuada, y los otros cuatro, que representan el 69,4% del área ( 86,1 ha, son manejados con tecnologías que no se corresponden con sus condiciones de RT (IT extensivas e inadecuadas, lo que conlleva a la subutilización y/o deterioro de sus condiciones biofísicas y ecológicas.The state, condition, and tendencies of the agrosystems (AS of the Cotové Farming Center of the Universidad Nacional de Colombia, Sede Medellín was evaluated by means of a parameterization and analysis of the various Receptivity Technologies (RT and Intensity Technologies (IT, based upon the proposed methodology of Vélez and Gastó (1999, in terms of the diversity in AE and the uses, management, and technological state, technostructural and hydrostructyural endowment, potential productivity and benefits to local, regional, and national society. Results showed that the majority of the area of the center (60% has high RT, that indicates the establishment of Mechanized Advanced Agrotechnological Management Systems (AMS, but only 15,72% of the area is managed with this SMA. Fully 69,3% of the area of the center, mainly under pasture for raising cattle, is managed with traditional SMA. As a product of the interaction between RT and the SMA employed, nine AE were identified, of which five, that represent 27,1% of the area ( 33,6 ha., are managed with technologies adequate for the biophysical conditions and the receptivity technology (adequate IT, and the other four, which represent 69,4% of the area ( 86,1 ha. are managed with technologies that do not correspond to their RT conditions (extensive and inadequate Its, that leads to a sub-utilization and/or deterioration of their biophysical and ecological conditions.

  17. Allometria da palmeira babaçu em um agroecossistema de derruba-e-queima na periferia este da Amazônia Allometry of the babassu palm growing on a slash-and-burn agroecosystem of the eastern periphery of Amazonia

    Directory of Open Access Journals (Sweden)

    Christoph Gehring

    2011-03-01

    Full Text Available A palmeira babaçu (Attalea speciosa C.Martius, Arecaceae tem grande importância socioeconômica e ecológica em grande parte da área tropical brasileira, especialmente em áreas degradadas por queimadas freqüentes na Amazônia. No entanto, ainda pouco se sabe sobre as características ecológicas desta espécie-chave. Este estudo investiga a alometria do babaçu com o objetivo de estabelecer uma metodologia eficiente na estimativa da biomassa aérea de palmeiras juvenis e adultas e para um melhor entendimento da sua arquitetura. A biomassa de palmeiras juvenis pode ser estimada facilmente e com precisão com o diâmetro mínimo das ráquis das folhas a 30 cm de extensão. A biomassa de palmeiras adultas pode ser estimada com base na altura do tronco lenhoso, também relativamente de fácil medição em campo. A biomassa foliar das palmeiras adultas foi em media 31,7% da biomassa aérea, porém houve uma alta variação e, portanto, somente pode ser estimada indiretamente através da relação entre a razão madeira:folha e biomassa aérea total. Os teores de carbono no babaçu apresentaram baixa variação, sem diferenças sistemáticas em relação ao tamanho ou estágio de crescimento, o que aponta à aplicabilidade geral dos valores 42.5% C para troncos, 39.8% C para folhas. Em conseqüência do limitado crescimento secundário do diâmetro inerente de palmeiras, não houve relação do diâmetro de tronco com a altura e a biomassa das palmeiras adultas. Observou-se que o afilamento do caule diminui com o aumento da altura das palmeiras, o que é parcialmente compensado pelo incremento da densidade de madeira em troncos quase-cilíndricos. No entanto, a altura máxima do babaçu, de cerca de 30 metros, aparentemente está definida por limitações na estabilidade mecânica. Todas as relações alométricas aqui descritas são independentes da idade da vegetação, indicando a aplicabilidade geral das relações encontradas.Babassu (Attalea speciosa C.Martius, Arecaceae is a palm with extraordinary socioeconomic and ecologic importance in large areas of tropical Brazil, especially in frequently burned and degraded landscapes. Nevertheless, surprisingly little is known about this keystone species. This paper investigates the allometry of babassu, in order to improve understanding on palm architecture and to provide researchers with an efficient tool for aboveground biomass estimation of juvenile and adult palms. Juvenile leaf biomass can be accurately predicted with the easily measurable minimum diameter of rachis at 30 cm extension. Adult palm biomass can be estimated based on woody stem height, a variable fairly easily measurable on-field. Leaf biomass of adult palms was highly variable, averaged 31.7% of aboveground biomass and can be estimated only indirectly through the relationships between wood:leaf-ratio and total aboveground biomass. Carbon contents varied little in the babassu palm, without size- or growth-stage related differences, suggesting the general applicability of values (42.5% C for stems, 39.8% C for leaves. As a consequence of the limited secondary diameter growth inherent to palms, stem diameter of adult palms is unrelated to palm height and biomass. Stem tapering decreases with increasing palm height. This is partially compensated by increasing wood density in near cylindrical stems. Nevertheless, maximum babassu palm height of about 30 meters appears to be dictated by mechanical stability constraints. All allometric relationships of babassu described in this study are not affected by vegetation stand age, indicating the general applicability of these relationships.

  18. Assessment of heavy metal flows in animal husbandry and development of a stategy to reduce heavy metal inputs into agro-ecosystems by animal manures; Erfassung von Schwermetallstroemen in landwirtschaftlichen Tierproduktionsbetrieben und Erarbeitung einer Konzeption zur Verringerung der Schwermetalleintraege durch Wirtschaftsduenger tierischer Herkunft in Agraroekosysteme

    Energy Technology Data Exchange (ETDEWEB)

    Schultheiss, U.; Doehler, H.; Roth, U.; Eckel, H.; Goldbach, H.; Kuehnen, V.; Wilcke, W.; Uihlein, A.; Fruechtenicht, K.; Steffens, G.

    2004-07-01

    The overall objectives of the project were to assess heavy metal flows on livestock farms and to develop a strategy to reduce heavy metal inputs into animal manures. For the experiments 20 farms with animal husbandry in various regions of Germany were selected. On the farms the inputs and outputs of the elements copper and zinc, as well as lead, cadmium, chromium and nickel were balanced at the stable level. The effect of abatement measures was evaluated using a calculation tool for stable balances. It is shown, the main input pathways for heavy metals into animal manures are, apart from copper disinfectants, feeding stuffs and feed supplements. Home grown feeds are the major source of heavy metal input into the stable because they are fed in large quantities. However, the heavy metal content of the home grown feeds in particular of roughages for ruminants is low. Purchased feed stuffs (supplementary feeding stuffs and complete feeding stuffs) were found to have a higher content of heavy metals (due to supplementation with trace elements) compared to home grown feeds. Thus, pig and poultry husbandry rather than ruminant husbandry is susceptible to heavy metal accumulation of manures. Heavy metals are cycling within the farm which is of importance when discussing the environmental impact. The turnover within the farm can hardly be controlled by the farmer. Thus, effective strategies have to be targeted at the inputs, e. g. the purchased feed stuffs. A main option to reduce the heavy metal input is to lower the trace element concentrations in supplementary feed stuffs either by legislation of maximum threshold values (e. g. EG 1334/2003) or by volunteer agreements of the feed industry and agriculture. In addition, the absorption of copper and zinc by the animals should be improved using better absorbable trace element compounds and phytase. (orig.)

  19. 论全球生态经济系统的不可持续性——基于农业生态系统承载力视角%On unsustainability of global economic ecosystem:based on the capacity of agro-ecosystem

    Institute of Scientific and Technical Information of China (English)

    蔡承智; 梁颖; 廖承红

    2010-01-01

    运用3种方法预测的作物产量潜力分别为:(1)利用作物历年单产回归拟合后进行趋势外推,得出多数作物的未来产量潜力极限大约将是现在单产的2~3倍;(2)运用"国际应用系统研究所"(IIASA)与"联合国粮农组织"(FAO)共同开发的"农业生态区划"(AEZ)模型计算我国主要粮油作物的区域单产最高潜力,得出水稻、小麦、玉米、马铃薯、油菜和大豆的单产潜力分别是它们2005年全国平均单产的1.2、2.2、2.2、2.9、2.0、1.9倍;(3)运用自然界中植物的最大光能利用率计算世界主要粮油作物单产的光合潜力,得出水稻、小麦、玉米、马铃薯、油菜、大豆产量的最大光合生产潜力大约分别是目前高产地区单产的1.4、2.5、1.2、1.8、1.9、2.2倍.据此:从作物产量潜力极限出发,阐述了农业生态系统的承载力;再从"封闭"系统特性出发,论述了全球生态经济系统的不可持续性.人类所能做的是尽力延缓"终点"的出现:行动越早,效果越好.

  20. Composition and functional groups of epiedaphic ants (Hymenoptera: Formicidae in irrigated agroecosystem and in nonagricultural areas Composição e grupos funcionais de formigas epiedáficas (Hymenoptera: Formicidae em agroecossistema irrigado e em áreas não agrícolas

    Directory of Open Access Journals (Sweden)

    Patricia Hernández-Ruiz

    2009-08-01

    Full Text Available The objective of this work was to evaluate the species composition and functional groups of ants in nonagricultural (NA and in irrigated areas (S, seasonal irrigation; P, irrigation with well water; W, irrigation with wastewater in an arid agricultural region in central Mexico, throughout 2005 and 2006. A total of 52,358 ants belonging to 6 subfamilies, 21 genera and 39 species was collected using pitfall traps. The species best represented in all plots were: Forelius pruinosus, Pheidole obtusospinosa, Monomorium minimum and Dorymyrmex spp. NA plots recorded the highest density of ants. The highest values for diversity (H' and equitativity (J' were recorded in NA and P plots, while the lowest were recorded in W plots. Cluster analysis showed two different groups regarding species composition: NA-S and W-P. Functional groups recorded were: dominant Dolichoderinae, three species; subordinate Camponotini, five species; hot climate specialists, three species; tropical climate specialists, seven species; cold climate specialists, five species; cryptic species, one species; opportunists, six species; generalized Myrmicinae, nine species. Agricultural activity affects the structure of the ant community with epiedaphic forage, and the constant use of irrigation wastewater in conjunction with intense agricultural practices has negative effect upon species richness of epiedaphic ants.O objetivo deste trabalho foi avaliar a composição de espécies e os grupos funcionais de formigas em áreas não agrícolas (NA e em áreas irrigadas (S, irrigação sazonal; P, irrigação com águas de poço; W, irrigação com água residuária em uma região agrícola de clima árido da região Central do México durante 2005 e 2006. Um total de 52.358 formigas pertencentes a 6 subfamílias, 21 gêneros e 39 espécies foi coletado por meio de armadilhas Pitfall. As espécies mais bem representadas em todas as parcelas foram: Forelius pruinosus, Pheidole obtusospinosa, Monomorium minimum e Dorymyrmex spp. As parcelas NA registraram a maior densidade de formigas. Os maiores valores de diversidade (H' e equitatividade (J' foram observados nas parcelas NA e P, e os menores, nas parcelas W. A análise de cluster mostrou grupos diferentes quanto à composição de espécies: NA-S e W-P. Os grupos funcionais registrados foram: Dolichoderinae dominantes, três espécies; Camponotini subordinadas, cinco espécies; especialistas de clima quente, três espécies; especialistas de clima tropical, sete espécies; especialistas de clima frio, cinco espécies; espécies crípticas, uma espécie; oportunistas, seis espécies; Myrmicinae generalizados, nove espécies. A atividade de agricultura afeta a estrutura das comunidades das formigas epiedáficas e a utilização constante de irrigação com água residuária, em conjunto com práticas agrícolas intensas tem um efeito negativo na riqueza de espécies de formigas epiedáficas.

  1. Population biology of the Grey Francolin (Francolinus pondicerianus) in an agro-ecosystem of the Pothwar Plateau, Pakistan%巴基斯坦波特瓦尔高原农业生态系统中灰鹧鸪(Francolinus pondicerianus)的种群生物学

    Institute of Scientific and Technical Information of China (English)

    Iftikhar HUSSAIN; Asmat-un-NISA; Sungum KHALIL

    2012-01-01

    我们于2009年在巴基斯坦波特瓦尔高原地区对农业生态系统中灰鹧鸪(Francolinus pondicerianus)的种群生物学进行了研究.该地区是灰鹧鸪在巴基斯坦的重要分布区之一.灰鹧鸪在作物区和灌丛林地的密度分别为每公顷1.59±0.39和0.87±0.14只,并且两种生境中的密度在季节间均稍有浮动.灰鹧鸪在由Desmostachia bipinnata、Acacia modesta、Imperata cylindrical、枣树(Zizipus jujuba)及大戟属(Euphorbia)等植物组成的植被地面营巢.产卵期为春夏两季,平均产卵期长约6±0.36天(5-7天),平均窝卵数为7±0.36枚(6-8枚).平均孵卵期为20.6±0.50天(19-22天).所记录的42枚卵中,32枚成功孵化(成功率76.19%),平均孵化率为每窝5.33±1.22枚.离巢雏鸟数约为每窝3.83±0.83只(离巢率63.08%).该鸟种为杂食性,亦食天牛.从该鸟的食物中鉴别出10个种类,包括7种植物:珍珠粟(Pennisetum typhoideum)、高粱(Sorghum bicolor)、假高粱(S.halepense)、牧豆树(Prosopis juliflora)、绿豆(Phaseolus radiates)、尖刺红花(Carthemus axycantha)及金合欢属(Acacia)某种植物,2种昆虫:家白蚁(Coptotermes formosanus)及红褐林蚁(Formica rufa),以及砂砾.

  2. Facilitative root interactions in intercrops

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, H.; Jensen, E.S.

    2005-01-01

    Facilitation takes place when plants ameliorate the environment of their neighbours, and increase their growth and survival. Facilitation occurs in natural ecosystems as well as in agroecosystems. We discuss examples of facilitative root interactions in intercropped agroecosystems; including...... intensified cropping systems using chemical and mechanical inputs also show that facilitative interactions definitely can be of significance. It is concluded that a better understanding of the mechanisms behind facilitative interactions may allow us to benefit more from these phenomena in agriculture...

  3. Genetic Diversity of Oilseed Rape Fields and Feral Populations in the Context of Coexistence with GM Crops

    OpenAIRE

    2016-01-01

    Despite growing concern about transgenes escaping from fields, few studies have analysed the genetic diversity of crops in an agroecosystem over several years. Accurate information about the dynamics and relationship of the genetic diversity of crops in an agroecosystem is essential for risk assessment and policies concerning the containment of genetically modified crops and their coexistence with crops grown by conventional practices. Here, we analysed the genetic diversity of oilseed rape p...

  4. First evidence of the effects of agricultural activities on gonadal form and function in Rhinella fernandezae and Dendropsophus sanborni (Amphibia: Anura from Entre Ríos Province, Argentina

    Directory of Open Access Journals (Sweden)

    Laura C. Sanchez

    2014-06-01

    Full Text Available The relationship between male gonadal abnormalities and habitats with different degrees of agricultural activities was quantified in two anuran species, Rhinella fernandezae and Dendropsophus sanborni. The study sites were selected along a gradient of increasing agricultural land use in south-western Entre Ríos province (Argentina: an agroecosystem, a natural wetland (a non-agricultural site adjacent to monoculture zones, and a natural forest (not associated with agriculture. Rhinella fernandezae and D. sanborni were manually captured from each environment during field surveys. A scaled mass index (MI was evaluated for each animal. Specimens of R. fernandezae from the agroecosystem and the natural wetland site presented poorly developed seminiferous tubules, lower testicular volume, and a lower number of seminiferous tubules, primary spermatogonia, and spermatids than specimens from the natural forest site. Additionally, we observed fewer primary spermatocytes in the agroecosystem group than in the natural forest group. Individuals of D. sanborni from the agroecosystem and the natural wetland site presented poorly developed tubules, higher proportions of irregularly shaped testes, and a reduced number of primary and secondary spermatogonia compared with specimens from natural forest sites. Consequently, the affected anurans are likely to have reduced reproductive success. We suggest that agrochemical use may be associated with decreased testicular development and function in both R. fernandezae and D. sanborni occurring in agroecosystems and nearby environments. Buffer zones are needed to prevent contamination, preserve wildlife, and enhance the conservation value of pristine natural forests.

  5. Towards a Better Understanding of Agronomic Efficiency of Nitrogen: Assessment and Improvement Strategies

    Directory of Open Access Journals (Sweden)

    Francesco Montemurro

    2016-05-01

    Full Text Available Agronomic N-use efficiency is the basis for economic and environmental efficiency, and an effective agro-ecosystem management practice, improving nutrient use efficiency, is a crucial challenge for a more sustainable production of horticultural, industrial and cereal crops. However, discrepancy between theory and practice still exists, coming from large gaps in knowledge on net-N immobilization/mineralization rates in agro-ecosystems, as well as on the effects of indigenous and applied N to crop response. A more thorough understanding of these topics is essential to improve N management in agricultural systems. To this end, the present Special Issue collects research findings dealing with different aspects of agronomic efficiency of N in different agro-ecosystems, and environmental impact derived from fertilization management practices. In particular, the Special Issue contains selected papers, which concern a wide range of topics, including analyzing tools, options of management, calculation equation and modeling approaches.

  6. Spatial distribution, blood feeding pattern, and role of Anopheles funestus complex in malaria transmission in central Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Kamau, Luna; Jacob, Benjamin G; Muriu, Simon; Mbogo, Charles M; Shililu, Josephat; Githure, John; Novak, Robert J

    2009-10-01

    Studies were conducted to determine the role of sibling species of Anopheles funestus complex in malaria transmission in three agro-ecosystems in central Kenya. Mosquitoes were sampled indoors and outdoors, and rDNA PCR was successfully used to identify 340 specimens. Anopheles parensis (91.8%), A. funestus (6.8%), and Anopheles leesoni (1.5%) were the three sibling species identified. A. parensis was the dominant species at all study sites, while 22 of 23 A. funestus were collected in the non-irrigated study site. None of the 362 specimens tested was positive for Plasmodium falciparum circumsporozoite proteins by enzyme-linked immunosorbent assay. The most common blood-meal sources (mixed blood meals included) for A. parensis were goat (54.0%), human (47.6%), and bovine (39.7%), while the few A. funestus s.s. samples had fed mostly on humans. The human blood index (HBI) for A. parensis (mixed blood meals included) in the non-irrigated agro-ecosystem was 0.93 and significantly higher than 0.33 in planned rice agro-ecosystem. The few samples of A. funestus s.s. and A. funestus s.l. also showed a trend of higher HBI in the non-irrigated agro-ecosystem. We conclude that agricultural practices have significant influence on distribution and blood feeding behavior of A. funestus complex. Although none of the species was implicated with malaria transmission, these results may partly explain why non-irrigated agro-ecosystems are associated with higher risk of malaria transmission by this species compared to irrigated agro-ecosystems.

  7. Exploring profit - Sustainability trade-offs in cropping systems using evolutionary algorithms

    NARCIS (Netherlands)

    DeVoil, P.; Rossing, W.A.H.; Hammer, G.L.

    2006-01-01

    Models that implement the bio-physical components of agro-ecosystems are ideally suited for exploring sustainability issues in cropping systems. Sustainability may be represented as a number of objectives to be maximised or minimised. However, the full decision space of these objectives is usually v

  8. Plus C'est La Meme Chose? Questioning Crop Diversification as a Response to Agricultural Deregulation in Saskatchewan, Canada

    Science.gov (United States)

    Bradshaw, Ben

    2004-01-01

    In the context of declining government subsidization of agriculture, many analysts have predicted reversals in certain characteristic trends of post-1945 Western agriculture with positive implications for agroecosystem well-being. One example, investigated herein, is the suggestion that, in the absence of government safety nets, farmers will seek…

  9. Do genetic modifications in crops affect soil fungi? a review

    NARCIS (Netherlands)

    Hannula, S.E.; Boer, de W.; Veen, van J.A.

    2014-01-01

    The use of genetically modified (GM) plants in agriculture has been a topic in public debate for over a decade. Despite their potential to increase yields, there may be unintended negative side-effects of GM plants on soil micro-organisms that are essential for functioning of agro-ecosystems. Fungi

  10. Identification of an atrazine-degrading benzoxazinoid in Eastern gamagrass (tripsacum dactyloides)

    Science.gov (United States)

    This study was part of a broader effort to identify and characterize promising atrazine-degrading phytochemicals in Eastern gamagrass (Tripsacum dactyloides; EG) roots for the purpose of mitigating atrazine transport from agroecosystems. The objective of this study was to isolate and identify atrazi...

  11. Enzyme Activity Dynamics in Response to Climate Change: 2011 Drought-Heat Wave

    Science.gov (United States)

    Extreme weather events such as severe droughts and heat waves may have permanent consequences on soil quality and functioning in agroecosystems. The Southern High Plains (SHP) region of Texas, U.S., a large cotton producing area, experienced a historically extreme drought and heat wave during 2011,...

  12. Atoxigenic Aspergillus flavus endemic to Italy for biocontrol of aflatoxins in maize

    Science.gov (United States)

    Effective biological control of aflatoxin­producing Aspergillus flavus with atoxigenic members of that species requires suitable A. flavus well adapted to and resident in target agroecosystems. Eighteen atoxigenic isolates of A. flavus endemic in Italy were compared for ability to reduce aflatoxin c...

  13. Agricultural Land Use and Conservation Options

    NARCIS (Netherlands)

    Zander, P.

    2003-01-01

    The thesis presents the modeling system MODAM (Multi-Objective Decision support tool for Agroecosystem Management) which was developed at the Centre for Agricultural Landscape and Land Use Research (ZALF) Müncheberg. The aim of the development of MODAM is to foster sustainable development o

  14. Long-term suspended sediment transport in the Goodwater Creek Experimental Watershed and Salt River Basin, Missouri, USA

    Science.gov (United States)

    Since 1992, efforts have been conducted in Goodwater Creek Experimental Watershed to assess sediment transport from this 72-km2 Missouri watershed located in the Salt River Basin, the Long-Term Agro-ecosystem Research site in the Central Mississippi River Basin. This effort was complemented by field...

  15. Heavy metals balance in Polish and Dutch agronomy : Actual state and previsions for the future

    NARCIS (Netherlands)

    Dach, J.; Starmans, D.A.J.

    2005-01-01

    This paper presents the state of agro-ecosystem contamination with heavy metals in relation to the level of agricultural development. For this, the Polish and Dutch agricultural situations were compared. The intensive animal and vegetable production observed in the Netherlands over the past 20-30 ye

  16. A crossing method for quinoa

    DEFF Research Database (Denmark)

    Peterson, Adam; Jacobsen, Sven-Erik; Bonifacio, Alejandro;

    2015-01-01

    As sustainable production of quinoa (Chenopodium quinoa Willd.) increases and its geographic range of cultivation expands, quinoa breeding will allow use of the crop’s wide genetic diversity for cultivar improvement and for adaptation to new agroecosystems and climactic regimes. Such breeding wor...

  17. 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.

    2016-01-01

    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…

  18. Simulation of long-term carbon and nitrogen dynamics in grassland-based dairy farming systems to evaluate mitigation strategies for nutrient losses

    NARCIS (Netherlands)

    Shah, G.A.; Groot, J.C.J.; Shah, G.M.; Lantinga, E.A.

    2013-01-01

    Many measures have been proposed to mitigate gaseous emissions and other nutrient losses from agroecosystems, which can have large detrimental effects for the quality of soils, water and air, and contribute to eutrophication and global warming. Due to complexities in farm management, biological inte

  19. Halosulfuron reduced purple nutsedge (Cyperus rotundus) tuber production and viability

    Science.gov (United States)

    Weeds persist and cause economic losses in agricultural systems because they exploit an underutilized portion of that system. Reducing the impact of weeds on agroecosystems begins with minimizing the number of propagules (e.g, seeds and tubers) that are produced and returned to the soil. Purple nu...

  20. Genetic, physiological and modelling approaches towards tolerance to salinity and low nitrogen supply in rice (Oryza sativa L.)

    NARCIS (Netherlands)

    Manneh, B.

    2004-01-01

    Keywords:   Rice, O ryza sativa , yield potential, yield gap, salinity, nitrogen supply, agro-ecosystems, Recombinant Inbred Line, genotype × environment interaction, yield components, adaptability, molecular markers, QTL, biomass, leaf area, leaf N, dry matter a

  1. Nitrogen balance in response to dryland crop rotations and cultural practices

    Science.gov (United States)

    Nitrogen balance provides a measure of agroecosystem performance and environmental sustainability by taking into accounts of N inputs and outputs and N retention in the soil. The objective of this study was to evaluate N balance based on N inputs and outputs and soil N sequestration after 7 yr in re...

  2. Net global warming potential and greenhouse gas intensity influenced by irrigation, tillage, crop rotation, and nitrogen fertilization

    Science.gov (United States)

    Little information exists about sources and sinks of greenhouse gases (GHGs) affected by management practices to account for net emissions from agroecosystems. We evaluated the effects of irrigation, tillage, crop rotation, and N fertilization on net global warming potential (GWP) and greenhouse gas...

  3. Net global warming potential and greenhouse gas intensity

    Science.gov (United States)

    Various methods exist to calculate global warming potential (GWP) and greenhouse gas intensity (GHG) as measures of net greenhouse gas (GHG) emissions from agroecosystems. Little is, however, known about net GWP and GHGI that account for all sources and sinks of GHG emissions. Sources of GHG include...

  4. Informe: Taller de descripción de las diferencias entre Aynokas y parcela privada y muestreo preliminar de suelos para caracterizar los tipos de suelos

    OpenAIRE

    Baylon, C.; Cóndor, Pedro

    2008-01-01

    La investigación tuvo como objetivos diferenciar los tipos de suelos según su manejo (parcela privada y aynokas) utilizando indicadores mas relevantes y muestrear suelos de la aynoka más representa de la comunidad. LTRA-4 (Practices and Strategies for Vulnerable Agro-Ecosystems)

  5. The Swiss agri-environment scheme enhances pollinator diversity and plant reproductive succes in nearby intensively managed farmland

    NARCIS (Netherlands)

    Albrecht, M.; Duelli, P.; Müller, C.; Kleijn, D.; Schmid, B.

    2007-01-01

    1. Agri-environment schemes attempt to counteract the loss of biodiversity and associated ecosystem services such as pollination and natural pest control in agro-ecosystems. However, only a few studies have evaluated whether these attempts are successful. 2. We studied the effects of managing meadow

  6. Fungal biomass development in a chronosequence of land abandonment

    NARCIS (Netherlands)

    Wal, van der A.; Veen, van J.A.; Smant, W.; Boschker, H.T.S.; Bloem, J.; Kardol, P.; Putten, van der W.H.; Boer, de W.

    2006-01-01

    Based on biomass size, the contribution of fungi to nutrient cycling and soil properties is in general more important in natural ecosystems than in agro-ecosystems. Therefore, we expect an increase of fungal biomass after cessation of cultivation to values of a natural ecosystem. However, so far, in

  7. The effect of flowering calendula and cuphea plants on Orius insidiosus survival and predation of Aphis glycines

    Science.gov (United States)

    Flowering oilseed crops have the potential to diversify agroecosystems currently dominated by corn and soybeans and improve the provision of ecosystem services such as pest control. Nectar and pollen feeding may increase natural enemy fitness and searching behavior, increasing their survival and pre...

  8. Agro-ecological characterization of inland valleys in West Arica

    NARCIS (Netherlands)

    Andriesse, W.; Windmeijer, P.N.; Duivenbooden, van N.

    1996-01-01

    Conceptual issues related to inland valleys, their morphology, hydrology and agro-ecosystems are discussed, as well as a method for their step-wise characterization at different levels of detail. A definition of inland valleys is given, including the description of the main landscape elements (uplan

  9. Root carbon input in organic and inorganic fertilizer-based systems

    DEFF Research Database (Denmark)

    Chirinda, Ngoni; Olesen, Jørgen E; Porter, John

    2012-01-01

    Background and aims In agroecosystems, carbon (C) inputs come from plant roots, retained shoot residues and in some cases from applied manures. Manure and shoot derived C inputs are relatively easy to determine. Conversely, high costs associated with root measurements have caused knowledge on root...

  10. Modeling carbon sequestration potential in Mollisols under climate change scenarios

    Science.gov (United States)

    Carbon sequestration in agricultural soils, besides its importance in mitigating global climate change, impacts and will be impacted by provisioning, regulating and supporting agroecosystem services. The objectives of this study were to (1) provide an improved understanding of the role of projected ...

  11. Simulating population recovery of an aquatic isopod: Effects of timing of stress and landscape structure

    NARCIS (Netherlands)

    Galic, N.G.; Baveco, J.M.; Hengeveld, G.M.; Thorbek, P.; Bruns, E.; Brink, van den P.J.

    2012-01-01

    In agroecosystems, organisms may regularly be exposed to anthropogenic stressors, e.g. pesticides. Species' sensitivity to stress depends on toxicity, life-history, and landscape structure. We developed an individual-based model of an isopod, Asellus aquaticus, to explore how timing of stress events

  12. Response of the reduviid bug, Rhynocoris marginatus (Heteroptera: Reduviidae) to six different species of cotton pests

    DEFF Research Database (Denmark)

    Sahayaraj, Kitherian; Muthu Kumar, Subramanian; Enkegaard, Annie

    2016-01-01

    In Indian agro-ecosystems Rhynocoris marginatus (F.) is one of the most abundant predatory arthropods and feeds on a wide range of insect pests. We investigated the responses of R. marginatus to six species of cotton pests: Spodoptera litura (F.), Sylepta derogata (F.), Pericallia ricini (F.), My...

  13. Integrating stakeholders' goals, research disciplines and levels of scale

    NARCIS (Netherlands)

    Duivenbooden, van N.

    1995-01-01

    This paper describes a methodological framework of a combination of high-tech assessment with participatory methodologies for developing sustainable agro-ecosystems. Basic ingredients are the integration of goals, disciplines, scales, and common methodologies. Quantification is another key issue. Im

  14. Object-Oriented Agricultural System Modeling: Component-Driven Nutrient Dynamics and Crop Yield Simulations

    Science.gov (United States)

    Challenges in agro-ecosystem conservation management have created demand for state-of-the-art, integrated, and flexible modeling tools. For example, agricultural system modeling tools are needed which are robust and fast enough to be applied on large watershed scales, but which are also able to sim...

  15. Investigación participativa en suelos

    OpenAIRE

    Chambilla, Carola; Gonzales, Miguel Angel

    2009-01-01

    Este poster presenta mapas y resultados de un estudio tecnico participativo con la comunidad de Kellhuiri sobre los tipos, ubicacion, estado y manejo agronomico de los suelos. Ademas, presenta resultados sobre el mejoramiento de los suelos como producto de la aplicacion de fertilizantes y enmiendas organicas. LTRA-4 (Practices and Strategies for Vulnerable Agro-Ecosystems)

  16. Manejo del cultivo de quinua

    OpenAIRE

    Chambilla, Carola

    2007-01-01

    Una presentación hecha a los agricultores del municipio de Umala en el que se describe las prácticas para el manejo integrado del cultivo. Se describe procesos de preparación del suelo, siembra, cosecha y poscosecha de la quinua. LTRA-4 (Practices and Strategies for Vulnerable Agro-Ecosystems)

  17. ASSESSING POSSIBLE ECOLOGICAL RISKS OF GENETICALLY MODIFIED CROPS: GENE EXPRESSION ASSAYS AND GENETIC MONITORING OF NON-TARGET ORGANISMS

    Science.gov (United States)

    Widespread planting of genetically modified crops with the Bt transgene pesticide has led to concern over non-target effects of Bt compounds in agroecosystems. While some research suggests that non-target organisms exposed to Bt toxin exhibit reduced fecundity and increased morta...

  18. Resource Management under Stressed Livelihood Conditions : Changing livelihoods and management practices in the bufferzone of the Kerinci Seblat National Park, Kerinci District, Sumatra

    NARCIS (Netherlands)

    Burgers, P.P.M.

    2004-01-01

    Poverty reduction in and around tropical forests and the reduction in speed at which natural tropical forests recede or become degraded, rank highly on the global agenda of sustainable development. The potentials of farmer-developed systems of sustainable forest management and agro-ecosystems, such

  19. Temporal and spatial changes in land use patterns and biodiversity in relation to farm productivity at multiple scales in Tigray, Ethiopia

    NARCIS (Netherlands)

    Hadgu Meles, K.

    2008-01-01

    Loss of biodiversity, including agro-biodiversity affects smallholders in dry-land regions by decreasing the buffering capacity of the agro-ecosystem and increasing proneness to yield variability including crop failure due to weather extremes. Loss of biodiversity is associated with land use/land co

  20. Spatially explicit analysis of land use change: a case study for Ecuador

    NARCIS (Netherlands)

    Koning, de F.

    1999-01-01

    Introduction and objectivesWithin agricultural research increasing attention is paid to the integrated study of agro-ecosystems in order to address issues related to sustainable food production at the eco-regional level. This has been stimulated by the awareness that the world-wide demand for food w

  1. Five thousand years of sustainability? : a case study on Gedeo land use (Southern Ethiopia)

    NARCIS (Netherlands)

    Kippie Kanshie, T.

    2002-01-01

    Key words : Ethiopia, Gedeo, ensete , pacemaker , spacemaker , placemaker, agroforest, agro-ecosystem, sustainability, biodiversity.The present volume is a study of an ancient way of land use, over five thousand years old, by the Gedeo in Ethiopia. The densely

  2. Development of the Land-use and Agricultural Management Practice web-Service (LAMPS) for generating crop rotations in space and time

    Science.gov (United States)

    Agroecosystem models and conservation planning tools require spatially and temporally explicit input data about agricultural management operations. The Land-use and Agricultural Management Practices web-Service (LAMPS) provides crop rotation and management information for user-specified areas within...

  3. Termites and agricultural production in the Sahel: from enemy to friend?

    NARCIS (Netherlands)

    Mando, A.; Rheenen, van T.

    1998-01-01

    Termites are an important component of agroecosystems, particularly in developing countries where they are an alternative to high priced inputs. Given the major problems in the Sahel of soil crusting and nutrient depletion, this paper shows that termites associated with proper management techniques

  4. Succession of root-associated fungi in Pisum sativum during a plant growth cycle as examined by 454 pyrosequencing

    DEFF Research Database (Denmark)

    Yu, L.; Nicolaisen, M.; Larsen, J.;

    2012-01-01

    Purpose Roots are inhabited by a broad range of fungi, including pathogens and mycorrhizal fungi, with functional traits related to plant health and nutrition. Management of these fungi in agroecosystems requires profound knowledge about their ecology. The main objective of this study was to exam...

  5. Characterization of Off-Road Diesel Emissions of Criteria Pollutants

    Science.gov (United States)

    2008-10-01

    calibration gas. The second generation Lidar system replaces the rigid tube with a larger (22” diameter) tube constructed of thin plastic foil, which can...agroecosystem for biobased production. Environ. Sci. Technol., 41(4):1457-1464. Lapuerta, M.; Hernandez, J.J.; Ballesteros, R.; and Duran, A. (2003

  6. Effects of a genetically modified potato on a non-target aphid are outweighed by cultivar differences

    NARCIS (Netherlands)

    Lazebnik, Jenny; Arpaia, Salvatore; Baldacchino, Ferdinando; Banzato, Paolo; Moliterni, Stefania; Vossen, Jack H.; Zande, van de Els M.; Loon, van Joop J.A.

    2017-01-01

    Insect–plant interactions may be unintentionally affected when introducing genetically modified (GM) crops into an agro-ecosystem. Our aim was to test the non-target effects of a late blight-resistant GM potato on Myzus persicae in greenhouse and climate room experiments and understand how positi

  7. Interrogating the plasmidome to determine antibiotic resistance gene mobility within the swine fecal microbiota

    Science.gov (United States)

    The use of antibiotics in animal production has been highlighted as a key contributor to the increasing prevalence of antibiotic resistance in agroecosystems. Gram negative bacteria, such as the Enterobacteriaceae, are important facilitators for resistance gene dissemination in the environment and i...

  8. Transmission of wild-type and recombinant HaSNPV among larvae of Helicoverpa armigera (Lepidoptera: Noctuidae) on cotton.

    NARCIS (Netherlands)

    Georgievska, L.; Vries, R.S.M.; Gao, P.; Sun, X.; Cory, J.S.; Vlak, J.M.; Werf, van der W.

    2010-01-01

    Horizontal transmission of insect viruses is a key factor in their cycling in agro-ecosystems. Here we study the transmission of the baculovirus HaSNPV among larvae of Helicoverpa armigera (Hübner) in cotton. Transmission of three HaSNPV genotypes was studied from larvae infected with a single virus

  9. Soil biota community structure and abundance under agricultural intensification and extensification

    NARCIS (Netherlands)

    Postma-Blaauw, M.B.; Goede, de R.G.M.; Bloem, J.; Faber, J.H.; Brussaard, L.

    2010-01-01

    Understanding the impacts of agricultural intensification and extensification on soil biota communities is useful in order to preserve and restore biological diversity in agricultural soils and enhance the role of soil biota in agroecosystem functioning. Over four consecutive years, we investigated

  10. Agroecology: Implications for plant response to climate change

    Science.gov (United States)

    Agricultural ecosystems (agroecosystems) represent the balance between the physiological responses of plants and plant canopies and the energy exchanges. Rising temperature and increasing CO2 coupled with an increase in variability of precipitation will create a complex set of interactions on plant ...

  11. Behavioral Changes Based on a Course in Agroecology: A Mixed Methods Study

    Science.gov (United States)

    Harms, Kristyn; King, James; Francis, Charles

    2009-01-01

    This study evaluated and described student perceptions of a course in agroecology to determine if participants experienced changed perceptions and behaviors resulting from the Agroecosystems Analysis course. A triangulation validating quantitative data mixed methods approach included a written survey comprised of both quantitative and open-ended…

  12. Options for carbon sequestration in West African soils: an exploratory study with special focus on Senegal

    NARCIS (Netherlands)

    Batjes, N.H.

    2001-01-01

    The organic matter content of many soils in West Africa has been depleted due to overgrazing, agricultural mismanagement, deforestation and overexploitation of the natural resources. Degraded agro(eco)systems can be managed to increase carbon sinks in vegetation and soil, and to reduce carbon emissi

  13. Genetics and characteristics of a pigmentation defective laboratory strain of the lady beetle, Coleomegilla maculata

    Science.gov (United States)

    Beetles in the family Coccinellidae, commonly known as ladybugs, lady beetles, or ladybirds, are easily identifiable and popular beneficial insects. The species complex Coleomegilla maculata is commonly found in North American agroecosystems and widespread on the North American continent. It is impo...

  14. Spiders (Araneae) as polyphagous natural enemies in orchards

    NARCIS (Netherlands)

    Bogya, S.

    1999-01-01

    Spiders (Araneae) occur in high abundance in all terrestrial ecosystems including agro-ecosystems. They are a very heterogeneous group of animals with different hunting tactics and therefore they play very different ecological roles. At family level these tactics are rather similar thus properties a

  15. Soil carbon and nitrogen losses following deforestation in Ethiopia

    Science.gov (United States)

    Dry Afromontane forests of Ethiopia have faced vast exploitation and almost all these forests have been converted to agricultural lands. The disappearance of the forests has been most drastic during the past 100 years and has affected the functionality and stability of agroecosystem. The dynamics in...

  16. Peranan Serasah Terhadap Sumbangan N dan P pada Agroekosistem Kopi

    Directory of Open Access Journals (Sweden)

    RUSDI EVIZAL

    2014-01-01

    Full Text Available Litter is the main source of organic matter and nutrient entrance in shade grown coffee agroecosystems.Shade trees provide ecological and economic benefits in coffee agro-ecosystems thatindicate the key factor for sustainable coffee production. This study examined the role of litter onnutrient (N and P returning in coffee agro-ecosystems. The experimental plots of Coffea canephorawere constucted at benchmark site of Conservation and Sustainable Management of Below-GroundBiodiversity (CSM-BGBD, in Sumberjaya Subdistrict, West Lampung, Indonesia, during 2007-2010.Types of shade trees to be examined were legume shade trees of Gliricidae sepium and Erythrinasububrams, non-legume tree of Michelia champaca, and no shade tree. The results showed that: (1kind of shading determined litter productivity of coffee agro-ecosystems. Litter productivity of coffeeagro-ecosystems with shade trees increased coffee bean yield, (2 litter was an important source of Nand P that returned into the soil. Amount of nitrogen from litter biomass has linier effect on coffee beanyield.

  17. Persistent negative effects of pesticides on biodiversity and biological control potential on European farmland

    NARCIS (Netherlands)

    Geiger, F.; Bengtsson, J.; Berendse, F.; Weisser, W.W.; Emmerson, M.; Morales, M.B.; Ceryngier, P.; Liira, J.; Tscharntke, T.; Winqvist, C.; Eggers, S.; Bommarco, R.; Pärt, T.; Bretagnolle, V.; Plantegenest, M.; Clement, L.W.; Dennis, C.; Palmer, C.; Oñate, J.J.; Guerrero, I.; Hawro, V.; Aavik, T.; Thies, C.; Flohre, A.; Hänke, S.; Fischer, C.; Goedhart, P.W.; Inchausti, P.

    2010-01-01

    During the last 50 years, agricultural intensification has caused many wild plant and animal species to go extinct regionally or nationally and has profoundly changed the functioning of agro-ecosystems. Agricultural intensification has many components, such as loss of landscape elements, enlarged fa

  18. Diet of tadpoles of Physalaemus biligonigerus (Leiuperidae from agricultural ponds in the central region of Argentina

    Directory of Open Access Journals (Sweden)

    Clarisa de Lourdes Bionda

    2013-12-01

    Full Text Available The intensification of agriculture has led an important loss of natural habitats, with significant consequences for biodiversity. In this sense, the studies on anuran amphibian tadpoles inhabiting these environments are relevant, because the larval stage is a phase of population regulation. The aim of this study was to analyze the diet in Physalaemus biligonigerus tadpoles, an anuran species widely distributed in South America and that inhabit agroecosystems. Three sites were sampled; two agroecosystems with different alteration degrees (AG1 and AG2 and an uncultured (SM third place. The captured tadpoles were anesthetized, fixed and preserved in formaldehyde (10%. Subsequently, the complete intestine was removed and analyzed for food items under a binocular microscope. The diet in P. biligonigerus tadpoles has a dominance of algae Bacillariophyceae, mainly in agroecosystems, due to the presence of the genera Navicula, Nitzschia and Gomphonema. There was a considerable abundance of the Gomphonema genus in the AG2 site. In addition, in the AG1 site several non-diatom algae were particularly abundant in the diet, such as the genera Euglena, Oedogonium and Chaetophora. In the SM site, the non-diatom genus Oscillatoria was well represented in the diet. Tadpoles inhabiting the site with abundant crop and livestock (AG1 ingested a significantly smaller amount of food. The presence of certain algae associated with eutrophic environments could indicate some pollution in agroecosystems (AG1 and AG2. Larval diet is suggested as a potential bioindicator of environmental health for these areas.

  19. Assessing the risks and benefits of flowering field edges. Strategic use of nectar sources to boost biological control

    NARCIS (Netherlands)

    Winkler, K.

    2005-01-01

    The intensification of agricultural production systems during the last decades hadaenormous impact on the landscape structure in agro-ecosystems. Landscape elements like hedges andvegetationalrichfieldmargins

  20. The Future of Food: Scenarios for 2050

    NARCIS (Netherlands)

    Hubert, B.; Rosegrant, M.; Boekel, van M.A.J.S.; Ortiz, R.

    2010-01-01

    This background article addresses key challenges of adequately feeding a population of 9 billion by 2050, while preserving the agro-ecosystems from which other services are also expected. One of the scenario-buildings uses the Agrimonde platform, which considers the following steps: choosing the sce

  1. Soil biodiversity for agricultural sustainability

    NARCIS (Netherlands)

    Brussaard, L.; Ruiter, de P.C.; Brown, G.G.

    2007-01-01

    We critically highlight some evidence for the importance of soil biodiversity to sustaining (agro-)ecosystem functioning and explore directions for future research. We first deal with resistance and resilience against abiotic disturbance and stress. There is evidence that soil biodiversity does conf

  2. Precision control of soil N cycling via soil functional zone management

    Science.gov (United States)

    Managing the soil nitrogen (N) cycle is a major component of agricultural sustainability. Soil functional zone management (SFZM), a novel framework of agroecosystem management, may improve soil N management compared with conventional and no-tillage approaches by focusing on the timing and location (...

  3. Effects of Prairie Restoration on Soil Quality Indicators

    Science.gov (United States)

    Characterization of soil ecosystem functioning based on soil quality assessments of native prairie may provide a reference for evaluating improvement in soil quality of cultivated agroecosystems converted to perennial vegetation during prairie restoration. Our objective was to determine the effect o...

  4. Soil quality indicator responses to row crop, grazed pasture, and agroforestry buffer management

    Science.gov (United States)

    Incorporation of trees and establishment of grass buffers within agroecosystems are management practices shown to enhance soil quality. Soil enzyme activities and water stable aggregates (WSA) have been identified as sensitive soil quality indicators to evaluate early responses to soil management. ...

  5. Co-evolutionary scenarios of intensification and privatization of resource use in rural communities of south-western Niger

    NARCIS (Netherlands)

    Rovere, La R.; Hiernaux, P.; Keulen, van H.; Schiere, J.B.; Szonyi, J.A.

    2005-01-01

    Agricultural production in the semi-arid agro-ecosystems of the Sahel centres on cereal staple crops and pastoralism with increasing crop-livestock integration. Animals mobilize soil fertility through manure production, graze crop by-products, and transfer nutrients from distant pastures to cropped

  6. Investing in Farmers: The Impacts of Farmer Field schools in relation to Integrated Pest Management

    NARCIS (Netherlands)

    Berg, van den H.; Jiggins, J.

    2007-01-01

    Public policy in developing countries has failed to invest in educating farmers on how to deal with variable agro-ecosystems and a changing world. Here we present an assessment of a participatory training approach in changing crop protection by farmers from chemically dependent, to more sustainable

  7. A quest for ecologically based pest management systems

    Science.gov (United States)

    Altieri, M. A.; Martin, P. B.; Lewis, W. J.

    1983-01-01

    The article presents a holistic approach to studying and applying crop protection in agricultural systems A theoretical framework of integrated pest management (IPM) is presented that allows an understanding of pest population processes on a whole-agroecological-system basis The need for and emergence of holistic research on agroecosystems is discussed, as are the current trends in ecological theory and pest management

  8. Poverty and biodiversity trade-offs in rural development: a case study for Pujiang county, China

    NARCIS (Netherlands)

    Hengsdijk, H.; Guanghuo, W.; Berg, van den M.M.; Jiangdi, W.; Wolf, J.; Changhe Lu,; Roetter, R.P.; Keulen, van H.

    2007-01-01

    Both, poverty reduction and preservation of biodiversity are high on the global agenda on sustainable development. The relationships between poverty, biodiversity of agro-ecosystems and agricultural development are complex and poorly understood. In this paper, we present an integrated framework for

  9. Oviposition and larval development of a stem borer, Eoreuma loftini, on rice and non-crop grass hosts

    Science.gov (United States)

    A greenhouse study compared oviposition preference and larval development duration of a stem borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), on rice, Oryza sativa L. (cv. Cocodrie), and four primary non-crop hosts of Gulf Coast Texas rice agroecosystems. Rice and two perennials, johnsongrass...

  10. Go with the flow by way of interdisciplinary collaboration: Sharing, integrating and opening access to data from various studies in the Cache la Poudre watershed following fire and flood

    Science.gov (United States)

    The United States Department of Agriculture, Agricultural Research Service Long-Term Agroecosystem Research (LTAR) Network consists of 18 sites across the continental United States. LTAR scientists seek to determine ways to ensure sustainability and enhance food production and ecosystem services at ...

  11. Proceedings of the Environmental Research and Development (R&D) technical Workshop Held in San Diego, California on 7-9 November 1989

    Science.gov (United States)

    1990-06-01

    Response of selected wildlife to planting time application of COUNTER 15-G systemic insecticide- nematicide in a corn agroecosystem. Institute of...investigation of the response of selected wildlife populations to planting time application of COUNTER-15G systemic insecticide- nematicide in an Iowa corn

  12. The first nitrogen index app for mobile devices: using portable technology for smart agricultural management

    Science.gov (United States)

    Nitrogen fertilizer from organic and inorganic sources is used across the world’s agroecosystems. It contributes to higher yields and higher economic returns to farmers, and is essential for food security. However, when more is applied than necessary, significant amounts of nitrogen can exit the sy...

  13. Crop resistance traits modify the effects of an aboveground herbivore, brown planthopper, on soil microbial biomass and nematode community via changes to plant performance.

    NARCIS (Netherlands)

    Huang, J.; Liu, M.; Chen, F.; Griffiths, B.S.; Chen, X.; Johnson, S.N.; Hu, F.

    2012-01-01

    Plant-mediated effects of aboveground herbivory on the belowground ecosystem are well documented, but less attention has been paid to agro-ecosystems and in particular how crop cultivars with different traits (i.e. resistance to pests) shape such interactions. A fully factorial experiment was conduc

  14. Pollen resources for pollinators in specialty oilseed crops

    Science.gov (United States)

    Simplified agroecosystems have depleted habitats for beneficial insects throughout the Midwest and Northern Great Plains of the USA. Beneficial insects include pollinators and natural enemies of crop pests, and both rely heavily on floral resources and habitat diversity to maintain healthy populatio...

  15. Evaluating bee (Hymenoptera: Apoidea) diversity using malaise traps in coffee landscapes of Costa Rica

    Science.gov (United States)

    Even though Arabica coffee (Coffea arabica Linnaeus, Rubiaceae) can self-pollinate, bees are important pollinators, without which there is lower fruit quality and yield. We studied bee diversity in coffee agroecosystems in Costa Rica during two coffee flowering seasons (2005 and 2006). Malaise traps...

  16. A New GIS-Nitrogen Trading Tool Concept to Minimize Reactive Nitrogen losses to the Environment

    Science.gov (United States)

    Nitrogen (N) is an essential element which is needed to maximize agricultural production and sustainability of worldwide agroecosystems. N losses to the environment are impacting water and air quality that has become an environmental concern for the future generations. It has led to the need for dev...

  17. A novel approach to estimate direct and indirect water withdrawals from satellite measurements: A case study from the Incomati basin

    NARCIS (Netherlands)

    Van Eekelen, M.W.; Bastiaanssen, W.G.M.; Jarmain, C.; Jackson, B.; Ferreira, F.; Van der Zaag, P.; Saraiva Okello, A.; Bosch, J.; Dye, P.; Bastidas-Obando, E.; Dost, R.J.J.; Luxemburg, W.M.J.

    2014-01-01

    The Incomati basin encompasses parts of South Africa, Swaziland and Mozambique, and is a water stressed basin. Equitable allocation of water is crucial to sustain livelihoods and agro-ecosystems, and to sustain international agreements. As compliance monitoring of water distribution by flow meters i

  18. Local Management Practices for Dealing with Change and Uncertainty: A Cross-scale Comparison of Cases in Sweden and Tanzania

    Directory of Open Access Journals (Sweden)

    Kristina Belfrage

    2004-12-01

    Full Text Available We investigated and compared management practices for dealing with uncertainty in agroecosystem dynamics in two cases of smallholder farming in different parts of the world: northeast Tanzania and east-central Sweden. Qualitative research methods were applied to map farmers' practices related to agroecosystem management. The practices are clustered according to a framework of ecosystem services relevant for agricultural production and discussed using a theoretical model of ecosystem dynamics. Almost half of the identified practices were found to be similar in both cases, with similar approaches for adjusting to and dealing with local variability and disturbance. Practices that embraced the ecological roles of wild as well as domesticated flora and fauna and the use of qualitative biological indicators are identified as tools that built insurance capital for change and enhanced the capacity to respond to changing agroecosystem dynamics. Diversification in time and space, as well as more specific practices for mitigating pest outbreaks and temporary droughts, can limit the effects of disturbance. In both Sweden and Tanzania, we identified social mechanisms for the protection of species that served important functions in the agroecosystem. We also found examples of how old practices served as a source of adaptations for dealing with new conditions and that new knowledge was adjusted to local conditions. The study shows that comparing management practices across scales and in different cultural settings can reveal insights into the capacity of farmers to adjust, respond to, and shape ecosystem dynamics. We emphasize the importance of continuous learning for developing the sustainable management of complex agroecosystems and securing agricultural production for the future.

  19. Exclusion of agricultural lands in spatial conservation prioritization strategies: consequences for biodiversity and ecosystem service representation.

    Science.gov (United States)

    Durán, América P; Duffy, James P; Gaston, Kevin J

    2014-10-01

    Agroecosystems have traditionally been considered incompatible with biological conservation goals, and often been excluded from spatial conservation prioritization strategies. The consequences for the representativeness of identified priority areas have been little explored. Here, we evaluate these for biodiversity and carbon storage representation when agricultural land areas are excluded from a spatial prioritization strategy for South America. Comparing different prioritization approaches, we also assess how the spatial overlap of priority areas changes. The exclusion of agricultural lands was detrimental to biodiversity representation, indicating that priority areas for agricultural production overlap with areas of relatively high occurrence of species. By contrast, exclusion of agricultural lands benefits representation of carbon storage within priority areas, as lands of high value for agriculture and carbon storage overlap little. When agricultural lands were included and equally weighted with biodiversity and carbon storage, a balanced representation resulted. Our findings suggest that with appropriate management, South American agroecosystems can significantly contribute to biodiversity conservation.

  20. Organic agriculture in the municipality of Alta Floresta-MT: case study on family based properties

    Directory of Open Access Journals (Sweden)

    Inês Caroline de Lima Proença

    2016-08-01

    Full Text Available Family farming has distinct characteristics in their organization and reproduction, such as the use of labor, family labor, the smallest territorial dimension of the plant and crop diversity. Organic agriculture has great potential for family farms, establishing more harmonious relationships between natural ecosystems and agricultural activities. In this context, this paper aims to study five units of organic farming family based in the municipality of Alta Floresta, state of Mato Grosso, making the general characterization of it and trying to identify the reality and the difficulties faced by these farmers. Data were made from semi-structured interviews and observation. It was found that the lack of technical assistance, the lack of access to rural credit facilities and lack of family labor are limiting factors that directly interfere with the management of agroecosystems. Furthermore, the great diversity of species managed is a key success factor in seeking and maintaining the stability of agroecosystems.