Sample records for agroecosystems

  1. AGROECOSYSTEM PILOT FIELD PROGRAM REPORT - 1992

    EPA Science Inventory

    The Agroecosystem Resource Group (ARG) of the Environmental Monitoring and Assessment Program (EMAP) has developed a five-year strategy for the development, evaluation, and implementation of a suite of indicators for monitoring the status and trends of agroecosystem condition on ...

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

    PubMed

    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 < 0.01)between urbanization rate and total 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.

  3. ENVIRONMENTAL MONITORING AND ASSESSMENT PROGRAM: AGROECOSYSTEM 1992 PILOT PLAN

    EPA Science Inventory

    The Agroecosystem Resource Group (ARG) of the Environmental Protection Monitoring and Assessment Program (EMAP) has developed a five year program strategy for implementation of a suite of indicators for monitoring agroecosystem status and trends. he five-year period (1991-1995) i...

  4. Organic carbon dynamics and soil stability in five semiarid agroecosystems

    USDA-ARS?s Scientific Manuscript database

    In the semiarid Texas High Plains where continuous cotton (CTN) is the dominate cropping practice, alternative agroecosystems such as integrated crop-livestock agroecosystems (ICL) are gaining interest for their versatility in management approaches to conserve water in this water-limited environment...

  5. ENVIRONMENTAL MONITORING AND ASSESSMENT PROGRAM - AGROECOSYSTEM PILOT FIELD PROGRAM PLAN - 1993

    EPA Science Inventory

    The Agroecosystem Resource Group (ARG) of the Environmental Monitoring and Assessment Program (EMAP) has developed a five-year (1991-1995) strategy for the development, evaluation, and implementation of a suite of indicators for monitoring agroecosystem status and trends on a reg...

  6. Agroecosystem research with big data and a modified scientific method using machine learning concepts

    USDA-ARS?s Scientific Manuscript database

    Long-term studies of agro-ecosystems at the continental scale are providing an extraordinary understanding of regional environmental dynamics. The new Long-Term Agro-ecosystem Research (LTAR) network (established in 2013) has designed an explicit research program with multiple USDA experimental wat...

  7. Nitrogen Cycling from Increased Soil Organic Carbon Contributes Both Positively and Negatively to Ecosystem Services in Wheat Agro-Ecosystems

    PubMed Central

    Palmer, Jeda; Thorburn, Peter J.; Biggs, Jody S.; Dominati, Estelle J.; Probert, Merv E.; Meier, Elizabeth A.; Huth, Neil I.; Dodd, Mike; Snow, Val; Larsen, Joshua R.; Parton, William J.

    2017-01-01

    Soil organic carbon (SOC) is an important and manageable property of soils that impacts on multiple ecosystem services through its effect on soil processes such as nitrogen (N) cycling and soil physical properties. There is considerable interest in increasing SOC concentration in agro-ecosystems worldwide. In some agro-ecosystems, increased SOC has been found to enhance the provision of ecosystem services such as the provision of food. However, increased SOC may increase the environmental footprint of some agro-ecosystems, for example by increasing nitrous oxide emissions. Given this uncertainty, progress is needed in quantifying the impact of increased SOC concentration on agro-ecosystems. Increased SOC concentration affects both N cycling and soil physical properties (i.e., water holding capacity). Thus, the aim of this study was to quantify the contribution, both positive and negative, of increased SOC concentration on ecosystem services provided by wheat agro-ecosystems. We used the Agricultural Production Systems sIMulator (APSIM) to represent the effect of increased SOC concentration on N cycling and soil physical properties, and used model outputs as proxies for multiple ecosystem services from wheat production agro-ecosystems at seven locations around the world. Under increased SOC, we found that N cycling had a larger effect on a range of ecosystem services (food provision, filtering of N, and nitrous oxide regulation) than soil physical properties. We predicted that food provision in these agro-ecosystems could be significantly increased by increased SOC concentration when N supply is limiting. Conversely, we predicted no significant benefit to food production from increasing SOC when soil N supply (from fertiliser and soil N stocks) is not limiting. The effect of increasing SOC on N cycling also led to significantly higher nitrous oxide emissions, although the relative increase was small. We also found that N losses via deep drainage were minimally affected by increased SOC in the dryland agro-ecosystems studied, but increased in the irrigated agro-ecosystem. Therefore, we show that under increased SOC concentration, N cycling contributes both positively and negatively to ecosystem services depending on supply, while the effects on soil physical properties are negligible. PMID:28539929

  8. Nitrogen Cycling from Increased Soil Organic Carbon Contributes Both Positively and Negatively to Ecosystem Services in Wheat Agro-Ecosystems.

    PubMed

    Palmer, Jeda; Thorburn, Peter J; Biggs, Jody S; Dominati, Estelle J; Probert, Merv E; Meier, Elizabeth A; Huth, Neil I; Dodd, Mike; Snow, Val; Larsen, Joshua R; Parton, William J

    2017-01-01

    Soil organic carbon (SOC) is an important and manageable property of soils that impacts on multiple ecosystem services through its effect on soil processes such as nitrogen (N) cycling and soil physical properties. There is considerable interest in increasing SOC concentration in agro-ecosystems worldwide. In some agro-ecosystems, increased SOC has been found to enhance the provision of ecosystem services such as the provision of food. However, increased SOC may increase the environmental footprint of some agro-ecosystems, for example by increasing nitrous oxide emissions. Given this uncertainty, progress is needed in quantifying the impact of increased SOC concentration on agro-ecosystems. Increased SOC concentration affects both N cycling and soil physical properties (i.e., water holding capacity). Thus, the aim of this study was to quantify the contribution, both positive and negative, of increased SOC concentration on ecosystem services provided by wheat agro-ecosystems. We used the Agricultural Production Systems sIMulator (APSIM) to represent the effect of increased SOC concentration on N cycling and soil physical properties, and used model outputs as proxies for multiple ecosystem services from wheat production agro-ecosystems at seven locations around the world. Under increased SOC, we found that N cycling had a larger effect on a range of ecosystem services (food provision, filtering of N, and nitrous oxide regulation) than soil physical properties. We predicted that food provision in these agro-ecosystems could be significantly increased by increased SOC concentration when N supply is limiting. Conversely, we predicted no significant benefit to food production from increasing SOC when soil N supply (from fertiliser and soil N stocks) is not limiting. The effect of increasing SOC on N cycling also led to significantly higher nitrous oxide emissions, although the relative increase was small. We also found that N losses via deep drainage were minimally affected by increased SOC in the dryland agro-ecosystems studied, but increased in the irrigated agro-ecosystem. Therefore, we show that under increased SOC concentration, N cycling contributes both positively and negatively to ecosystem services depending on supply, while the effects on soil physical properties are negligible.

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

    NASA Astrophysics Data System (ADS)

    Yang, Jin; Chen, Weichao; Chen, Bin

    2011-09-01

    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 agro-ecosystem 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.

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

    EPA Science Inventory

    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...

  11. Scale and the representation of human agency in the modeling of agroecosystems

    DOE PAGES

    Preston, Benjamin L.; King, Anthony W.; Ernst, Kathleen M.; ...

    2015-07-17

    Human agency is an essential determinant of the dynamics of agroecosystems. However, the manner in which agency is represented within different approaches to agroecosystem modeling is largely contingent on the scales of analysis and the conceptualization of the system of interest. While appropriate at times, narrow conceptualizations of agroecosystems can preclude consideration for how agency manifests at different scales, thereby marginalizing processes, feedbacks, and constraints that would otherwise affect model results. Modifications to the existing modeling toolkit may therefore enable more holistic representations of human agency. Model integration can assist with the development of multi-scale agroecosystem modeling frameworks that capturemore » different aspects of agency. In addition, expanding the use of socioeconomic scenarios and stakeholder participation can assist in explicitly defining context-dependent elements of scale and agency. Finally, such approaches, however, should be accompanied by greater recognition of the meta agency of model users and the need for more critical evaluation of model selection and application.« less

  12. The Framework of the Maintenance Ecosystem Services Provided by Agroecosystems on the Territory of Bulgaria

    NASA Astrophysics Data System (ADS)

    Kenarova, Anelia; Tzonev, Rossen; Boteva, Silvena; Bogoev, Valentin; Nikolov, Marian; Pachedjieva, Kalina; Traykov, Ivan; Simeonovska-Nikolova, Daniela; Dimitrov, Krastio; Stefanov, Vladimir; Bakardjieva, Hristina; Dimitrova, Tsveta; Nachev, Georgi

    2017-12-01

    Over the past decade, efforts to value and protect ecosystem services have been promoted by many as the last, best hope for making conservation mainstream. Here, we present the results from the evaluation of the maintenance ecosystem services, provided by the agroecosystems in Bulgaria. The evaluation was conducted on a range of national, European and international databases following the methodology of MAES and classification system of CICES adapted by the Bulgarian Ministry of Environment and Water. During the study, 213857 agroecosystems were evaluated referring to their capacity to maintain pollinators, natural pest control, soil quality and atmospheric carbon sequestration. The capacity of agroecosystems to provide the above mentioned ecosystem services was ranged from moderate to very high, tending the mountainous agroecosystems to be more beneficial than that located in the plains and lowlands. The intensive management of the latter in order to achieve perceived efficiencies in the production of agricultural goods reduces their importance for local and regional ecological processes.

  13. A review on reflective remote sensing and data assimilation techniques for enhanced agroecosystem modeling

    NASA Astrophysics Data System (ADS)

    Dorigo, W. A.; Zurita-Milla, R.; de Wit, A. J. W.; Brazile, J.; Singh, R.; Schaepman, M. E.

    2007-05-01

    During the last 50 years, the management of agroecosystems has been undergoing major changes to meet the growing demand for food, timber, fibre and fuel. As a result of this intensified use, the ecological status of many agroecosystems has been severely deteriorated. Modeling the behavior of agroecosystems is, therefore, of great help since it allows the definition of management strategies that maximize (crop) production while minimizing the environmental impacts. Remote sensing can support such modeling by offering information on the spatial and temporal variation of important canopy state variables which would be very difficult to obtain otherwise. In this paper, we present an overview of different methods that can be used to derive biophysical and biochemical canopy state variables from optical remote sensing data in the VNIR-SWIR regions. The overview is based on an extensive literature review where both statistical-empirical and physically based methods are discussed. Subsequently, the prevailing techniques of assimilating remote sensing data into agroecosystem models are outlined. The increasing complexity of data assimilation methods and of models describing agroecosystem functioning has significantly increased computational demands. For this reason, we include a short section on the potential of parallel processing to deal with the complex and computationally intensive algorithms described in the preceding sections. The studied literature reveals that many valuable techniques have been developed both for the retrieval of canopy state variables from reflective remote sensing data as for assimilating the retrieved variables in agroecosystem models. However, for agroecosystem modeling and remote sensing data assimilation to be commonly employed on a global operational basis, emphasis will have to be put on bridging the mismatch between data availability and accuracy on one hand, and model and user requirements on the other. This could be achieved by integrating imagery with different spatial, temporal, spectral, and angular resolutions, and the fusion of optical data with data of different origin, such as LIDAR and radar/microwave.

  14. Production and Robustness of a Cacao Agroecosystem: Effects of Two Contrasting Types of Management Strategies

    PubMed Central

    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. PMID:24312469

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

    PubMed

    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.

  16. [Changes of agroecosystem services value under effects of land consolidation].

    PubMed

    Zhang, Zhen; Gao, Jin-Quan; Wei, Chao-Fu

    2010-03-01

    This paper quantitatively described the changes of agroecosystem functions before (2003) and after (2007) the implementation of Gaolong land consolidation project in Hechuan of Chongqing. Engineering design and shadow price were integrated to quantify the effects of the project on the functions, and cost-benefit analysis was used to further explain the economic meanings of the functions, and to analyze the changes of the agroecosystem services value under effects of the project. Compared with that before the land consolidation, the agroecosystem services value after the land consolidation was somewhat improved, with the largest increment of nutrient cycling function and the smallest change of soil conservation function. In the implementation of the project, the changes of the agroecosystem services value induced by farmland water conservancy, field road building, and land-leveling engineering mainly manifested in the change of disturbance function. From the 7th to 35th year after the project, the cost benefit would have a rapid increase, and tended to be stable after then, giving a weak ecological pressure and little services value loss, and benefiting the improvement of regional ecological environment.

  17. In-Field Habitat Management to Optimize Pest Control of Novel Soil Communities in Agroecosystems

    PubMed Central

    Pearsons, Kirsten A.

    2017-01-01

    The challenge of managing agroecosystems on a landscape scale and the novel structure of soil communities in agroecosystems both provide reason to focus on in-field management practices, including cover crop adoption, reduced tillage, and judicial pesticide use, to promote soil community diversity. Belowground and epigeal arthropods, especially exotic generalist predators, play a significant role in controlling insect pests, weeds, and pathogens in agroecosystems. However, the preventative pest management tactics that dominate field-crop production in the United States do not promote biological control. In this review, we argue that by reducing disturbance, mitigating the effects of necessary field activities, and controlling pests within an Integrated Pest Management framework, farmers can facilitate the diversity and activity of native and exotic arthropod predators. PMID:28783074

  18. In-Field Habitat Management to Optimize Pest Control of Novel Soil Communities in Agroecosystems.

    PubMed

    Pearsons, Kirsten A; Tooker, John F

    2017-08-05

    The challenge of managing agroecosystems on a landscape scale and the novel structure of soil communities in agroecosystems both provide reason to focus on in-field management practices, including cover crop adoption, reduced tillage, and judicial pesticide use, to promote soil community diversity. Belowground and epigeal arthropods, especially exotic generalist predators, play a significant role in controlling insect pests, weeds, and pathogens in agroecosystems. However, the preventative pest management tactics that dominate field-crop production in the United States do not promote biological control. In this review, we argue that by reducing disturbance, mitigating the effects of necessary field activities, and controlling pests within an Integrated Pest Management framework, farmers can facilitate the diversity and activity of native and exotic arthropod predators.

  19. Spatial heterogeneity in human activities favors the persistence of wolves in agroecosystems.

    PubMed

    Ahmadi, Mohsen; López-Bao, José Vicente; Kaboli, Mohammad

    2014-01-01

    As human populations expand, there is increasing demand and pressure for land. Under this scenario, behavioural flexibility and adaptation become important processes leading to the persistence of large carnivores in human-dominated landscapes such as agroecosystems. A growing interest has recently emerged on the outcome of the coexistence between wolves and humans in these systems. It has been suggested that spatial heterogeneity in human activities would be a major environmental factor modulating vulnerability and persistence of this contentious species in agroecosystems. Here, we combined information from 35 den sites detected between 2011 and 2012 in agroecosystems of western Iran (Hamedan province), a set of environmental variables measured at landscape and fine spatial scales, and generalized linear models to identify patterns of den site selection by wolves in a highly-modified agroecosystem. On a landscape level, wolves selected a mixture of rangelands with scattered dry-farms on hillsides (showing a low human use) to locate their dens, avoiding areas with high densities of settlements and primary roads. On a fine spatial scale, wolves primarily excavated dens into the sides of elevated steep-slope hills with availability of water bodies in the vicinity of den sites, and wolves were relegated to dig in places with coarse-soil particles. Our results suggest that vulnerability of wolves in human-dominated landscapes could be compensated by the existence of spatial heterogeneity in human activities. Such heterogeneity would favor wolf persistence in agroecosystems favoring a land sharing model of coexistence between wolves and people.

  20. Spatial Heterogeneity in Human Activities Favors the Persistence of Wolves in Agroecosystems

    PubMed Central

    Ahmadi, Mohsen; López-Bao, José Vicente; Kaboli, Mohammad

    2014-01-01

    As human populations expand, there is increasing demand and pressure for land. Under this scenario, behavioural flexibility and adaptation become important processes leading to the persistence of large carnivores in human-dominated landscapes such as agroecosystems. A growing interest has recently emerged on the outcome of the coexistence between wolves and humans in these systems. It has been suggested that spatial heterogeneity in human activities would be a major environmental factor modulating vulnerability and persistence of this contentious species in agroecosystems. Here, we combined information from 35 den sites detected between 2011 and 2012 in agroecosystems of western Iran (Hamedan province), a set of environmental variables measured at landscape and fine spatial scales, and generalized linear models to identify patterns of den site selection by wolves in a highly-modified agroecosystem. On a landscape level, wolves selected a mixture of rangelands with scattered dry-farms on hillsides (showing a low human use) to locate their dens, avoiding areas with high densities of settlements and primary roads. On a fine spatial scale, wolves primarily excavated dens into the sides of elevated steep-slope hills with availability of water bodies in the vicinity of den sites, and wolves were relegated to dig in places with coarse-soil particles. Our results suggest that vulnerability of wolves in human-dominated landscapes could be compensated by the existence of spatial heterogeneity in human activities. Such heterogeneity would favor wolf persistence in agroecosystems favoring a land sharing model of coexistence between wolves and people. PMID:25251567

  1. Effects of Climate Changes and Pollution with Heavy Metals on the Transformation of Carbon Compounds in Different Soil Types of Agroecosystems in the Forest-Steppe of Baikal Region

    NASA Astrophysics Data System (ADS)

    Pomazkina, L. V.; Semenova, Yu. V.

    2018-05-01

    The results of long-term (1992-2005) monitoring of the carbon compounds transformation in soils of forest- steppe agroecosystems polluted by heavy metals in the Baikal region in the years different from the "climatic norm" are discussed. The influence of environmental factors on the functioning of microbial community was estimated by the Cmicr content and CO2 emission. The changes in the ecophysiological parameters (Cmicr/Corg and C-CO2/Cmicr, mg/(g h) related to the availability of the substrate and intensity of carbon (re)immobilization in different soils revealed the differences in the formation of a stable microbial community dependent on the environmental factors, especially in anomalous years. The use of a systemic approach and analysis of the carbon compounds transformation based on the proportion between the flows of net-mineralized and (re)immobilized carbon (NM: RI) allowed to evaluate integrally the functioning regime of the agroecosystems and the ecological impact on them. The differences in the functioning of agroecosystems on different heavy metal-polluted soils identified on the background of climatic changes are suitable for forecasting the current state and development of agroecosystems. For agroecosystems of this region, C-CO2 emission was estimated for the first time; it was more intense from the soils with the high humus content than from the soils poor in humus (141 and 101 g C/m2, respectively).

  2. Spider fauna of semiarid eastern Colorado agroecosystems: diversity, abundance, and effects of crop intensification.

    PubMed

    Kerzicnik, Lauren M; Peairs, Frank B; Cushing, Paula E; Draney, Michael L; Merrill, Scott C

    2013-02-01

    Spiders are critical predators in agroecosystems. Crop management practices can influence predator density and diversity, which, in turn, can influence pest management strategies. Crop intensification is a sustainable agricultural technique that can enhance crop production although optimizing soil moisture. To date, there is no information on how crop intensification affects natural enemy populations, particularly spiders. This study had two objectives: to characterize the abundance and diversity of spiders in eastern Colorado agroecosystems, and to test the hypothesis that spider diversity and density would be higher in wheat (Triticum aestivum L.) in crop-intensified rotations compared with wheat in conventional rotations. We collected spiders through pitfall, vacuum, and lookdown sampling from 2002 to 2007 to test these objectives. Over 11,000 spiders in 19 families from 119 species were captured from all sampling techniques. Interestingly, the hunting spider guild represented 89% of the spider fauna captured from all sites with the families Gnaphosidae and Lycosidae representing 75% of these spiders. Compared with European agroecosystems, these agroecosystems had greater diversity, which can be beneficial for the biological control of pests. Overall, spider densities were low in these semiarid cropping systems, and crop intensification effects on spider densities were not evident at this scale.

  3. [Environmental benefit-loss analysis of agro-ecosystem in Haihe River Basin, China].

    PubMed

    Bai, Yang; Ouyang, Zhi-yun; Zheng, Hua; Xu, Wei-hua; Jiang, Bo; Fang, Yu

    2010-11-01

    According to the connotation of ecosystem services, an evaluation index system for the agro-ecosystem services in the Haihe River basin of China was established, and the economic value of the agro-ecosystem services and environmental costs were evaluated by the methods of market valuation, shadow price, and opportunity cost. In 2005, the total environmental benefit value of the agro-ecosystem services in the basin was 180. 264 billion RMB, with the regulation value of 79.416 billion RMB (44.06%) and the supporting value of 100.848 billion RMB (55.94%). Provision and cultural services were not considered in this research. From the viewpoint of functional type, the ecosystem services value from high to low was in the order of oxygen release > water conservation > nutrient cycling > soil conservation > waste purification > environmental purification > carbon sequestration > straw returning. The environmental costs of the agro-ecosystem were quite high (42. 293 billion RMB), among which, fertilizer loss was 427.42 x 10(4) t, equivalent to 15.191 billion RMB, and greenhouse gases production was calculated as 3599.65 x 10(4) t CO2, equivalent to 27. 102 billion RMB.

  4. Climate Change Vulnerability of Agro-Ecosystems: Does socio-economic factors matters?

    NASA Astrophysics Data System (ADS)

    Surendran Nair, S.; Preston, B. L.; King, A. W.; Mei, R.; Post, W. M.

    2013-12-01

    Climate variability and change has direct impacts on agriculture. Despite continual adaptation to climate as well as gains in technology innovation and adoption, agriculture is still vulnerable to changes in temperature and precipitation expected in coming decades. Generally, researchers use two major methodologies to understand the vulnerability of agro-ecosystems to climate change: process-based crop models and empirical models. However, these models are not yet designed to capture the influence of socioeconomic systems on agro-ecosystem processes and outcomes.. However, socioeconomic processes are an important factor driving agro-ecological responses to biophysical processes (climate, topography and soil), because of the role of human agency in mediating the response of agro-ecosystems to climate. We have developed a framework that integrates socioeconomic and biophysical characteristics of agro-ecosystems using cluster analysis and GIS tools. This framework has been applied to the U.S. Southeast to define unique socio-ecological domains for agriculture. The results demonstrate that socioeconomic characteristics are an important factor influencing agriculture production. These results suggest that the lack of attention to socioeconomic conditions and human agency in agro-ecological modeling creates a potential bias with respect to the representation of climate change impacts.

  5. Natural ecosystem mimicry in traditional dryland agroecosystems: Insights from an empirical and holistic approach.

    PubMed

    Blanco, Julien; Michon, Geneviève; Carrière, Stéphanie M

    2017-12-15

    While the aim of Ecological Intensification is to enable the design of more sustainable and productive agricultural systems, it is not suited to dryland agroecosystems that are driven by non-equilibrium dynamics and intrinsic variability. Instead, a model based on mobility and variability management has been proposed for these agroecosystems. However, this model remains under-applied in southern Morocco where there have been few studies on the functioning of traditional agroecosystems. This paper focuses on an agroecosystem in the Moroccan Saharan fringe zone that combines agriculture and pastoralism in an acacia parkland. A grounded theory approach was used over a three-year investigation period (i) to highlight how agro-pastoral activities interface with environmental variability, and (ii) to analyze the formal and informal institutions that support these activities. Results show that farmers interface with rainfall variability through (i) an opportunistic agricultural calendar, (ii) a variation of cultivated areas, and (iii) crop diversification. Herders combine macro-mobility (nomads move over long distances to track rainfall) and micro-mobility (nomadic and sedentary herds are driven on a daily basis around settlements) to optimize the exploitation of ecological heterogeneity. During droughts, they also resort to State-subsidized forage supplies. Both cultivation and pastoral activities tend to interface with ecological dynamics and to mimic nature, resulting in a human-modified parkland that could be considered as a 'green agroecosystem'. The sustainability of natural resource use relies on flexible property rights, backed up by a social and cultural norm-based regulation system, that allow crop-livestock integration and landscape collective management. Despite encouraging results, the agroecosystem appears to be threatened by current agricultural policies, rural exodus and the lack of social recognition of nomadism. Nevertheless, because ecosystem mimicry of nature is often considered as a sound agricultural model for drylands, this case study could provide a basis for local development policies, and thus merits further attention from local managers and researchers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Preston, Benjamin L.; King, Anthony W.; Ernst, Kathleen M.

    Human agency is an essential determinant of the dynamics of agroecosystems. However, the manner in which agency is represented within different approaches to agroecosystem modeling is largely contingent on the scales of analysis and the conceptualization of the system of interest. While appropriate at times, narrow conceptualizations of agroecosystems can preclude consideration for how agency manifests at different scales, thereby marginalizing processes, feedbacks, and constraints that would otherwise affect model results. Modifications to the existing modeling toolkit may therefore enable more holistic representations of human agency. Model integration can assist with the development of multi-scale agroecosystem modeling frameworks that capturemore » different aspects of agency. In addition, expanding the use of socioeconomic scenarios and stakeholder participation can assist in explicitly defining context-dependent elements of scale and agency. Finally, such approaches, however, should be accompanied by greater recognition of the meta agency of model users and the need for more critical evaluation of model selection and application.« less

  7. Pollinators, pests, and predators: Recognizing ecological trade-offs in agroecosystems.

    PubMed

    Saunders, Manu E; Peisley, Rebecca K; Rader, Romina; Luck, Gary W

    2016-02-01

    Ecological interactions between crops and wild animals frequently result in increases or declines in crop yield. Yet, positive and negative interactions have mostly been treated independently, owing partly to disciplinary silos in ecological and agricultural sciences. We advocate a new integrated research paradigm that explicitly recognizes cost-benefit trade-offs among animal activities and acknowledges that these activities occur within social-ecological contexts. Support for this paradigm is presented in an evidence-based conceptual model structured around five evidence statements highlighting emerging trends applicable to sustainable agriculture. The full range of benefits and costs associated with animal activities in agroecosystems cannot be quantified by focusing on single species groups, crops, or systems. Management of productive agroecosystems should sustain cycles of ecological interactions between crops and wild animals, not isolate these cycles from the system. Advancing this paradigm will therefore require integrated studies that determine net returns of animal activity in agroecosystems.

  8. Sustainable land management practices as providers of several ecosystem services under rainfed Mediterranean agroecosystems

    NASA Astrophysics Data System (ADS)

    Almagro, María; de Vente, Joris; Boix-Fayós, Carolina; García-Franco, Noelia; Melgares de Aguilar, Javier; González, David; Solé-Benet, Albert; Martínez-Mena, María

    2015-04-01

    Little is known about the multiple impacts of sustainable land management practices on soil and water conservation, carbon sequestration, mitigation of global warming, and crop yield productivity in semiarid Mediterranean agroecosystems. We hypothesized that a shift from intensive tillage to more conservative tillage management practices (reduced tillage optionally combined with green manure) leads to an improvement in soil structure and quality and will reduce soil erosion and enhance carbon sequestration in semiarid Mediterranean rainfed agroecosystems. To test the hypothesis, we assessed the effects of different tillage treatments (conventional (CT), reduced (RT), reduced tillage combined with green manure (RTG), and no tillage (NT)) on soil structure and soil water content, runoff and erosion control, soil CO2 emissions, crop yield and carbon sequestration in two semiarid agroecosystems with organic rainfed almond in the Murcia Region southeast Spain). It was found that reduction and suppression of tillage under almonds led to an increase in soil water content in both agroecosystems. Crop yields ranged from 775 to 1766 kg ha-1 between tillage 18 treatments, but we did not find a clear relation between soil water content and crop yield. RT and RTG treatments showed lower soil erosion rates and higher crop yields of almonds than under CT treatment. Overall, higher soil organic carbon contents and aggregate stability were observed under RTG treatment than under RT or CT treatment. It is concluded that conversion from CT to RTG is suitable to increase carbon inputs without enhancing soil CO2 emissions in semiarid Mediterranean agroecosystems.

  9. Determination of nitrogen balance in agroecosystems

    USDA-ARS?s Scientific Manuscript database

    Nitrogen balance in agroecosystems provides a quantitative framework of N inputs and outputs and retention in the soil that examine sustainability of agricultural productivity and soil and environmental quality. Nitrogen inputs include N additions from manures and fertilizers, atmospheric deposition...

  10. EMTERNALITIES - THE CASE OF AGRO-ECOSYSTEMS

    EPA Science Inventory

    This paper deals with the role of ecosystem services prior to crop production and uses this example to introduce emternalites in agro-ecosystems. Emternalities are best viewed as the quasi counterpart of established economic externalities, except that they designate unassessed i...

  11. Reproductive endpoints of Rhinella arenarum (Anura, Bufonidae): Populations that persist in agroecosystems and their use for the environmental health assessment.

    PubMed

    Babini, María Selene; de Lourdes Bionda, Clarisa; Salinas, Zulma Anahí; Salas, Nancy Edith; Martino, Adolfo Ludovico

    2018-06-15

    Degradation of the environment by agriculture affects the persistence and health of the amphibian populations. Characteristics related to reproduction of anuran can be used to evaluate the status of populations and as endpoints in environmental health assessment. In this in situ study the aspects related to the amplexus and ovipositions of the bioindicator species Rhinella arenarum that inhabits agroecosystems were analyzed. The hypothesis of this study is that perturbations of agroecosystems have a negative impact on the size of reproductive adults, on the size of ovipositions and eggs, and on the survival of eggs and embryos. Study area is located in the rural landscape of central Argentina. Four sampling sites were selected: C1, C2 and C3 are ponds on agroecosystems; and SM is a reference site that is not affected by agriculture or livestock. Abundance of amplexus pairs, oviposition and tadpoles per site was recorded. Individuals´ snout-vent length (SVL) in amplexus was measured. The fecundity was calculated like number of eggs per oviposition. The eggs' Gosner stage, the diameter eggs and the frequency of dead and abnormal eggs were recorded by oviposition. Killing-power between egg-embryo and egg-tadpole was calculated. The higher phosphate concentration was detected in all agroecosystems and nitrate was detected in C1 and C2. Conductivity, salinity and SDT were higher in C1 site Male SVL from the SM site was lower than the other sites while the largest SVL was of female from the C3 site. The higher frequencies of sprouted eggs and of dead eggs were recorded in the C2 site. Egg diameter was associated with SM and correlated negatively to SVL of the male and female. No correlation between female SVL and oviposition size was recorded. Killing-power in the passage from egg to tadpole classes was higher in the three agroecosystems. The hypothesis of this study was corroborated in part. Reproductive adults in agroecosystems did not have smaller body size. However, in the agroecosystem ponds, the eggs with smaller diameter were registered, the oviposition had higher frequency of abnormal eggs and the higher mortality was registered. This confirms the high sensitivity of the early stages to environmental disturbances and sustains their use as endpoints for the environmental health assessment. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. The Long Term Agroecosystem Research Network - Shared research strategy

    USDA-ARS?s Scientific Manuscript database

    Agriculture faces tremendous challenges in meeting multiple societal goals, including a safe and plentiful food supply; climate change adaptation and mitigation; supplying sources of bioenergy; improving water, air, and soil quality; and maintaining biodiversity. The Long Term Agroecosystem Research...

  13. Benefits of increasing plant diversity in sustainable agroecosystems

    USDA-ARS?s Scientific Manuscript database

    Recent studies have revealed many potential benefits of increasing plant diversity in agroecosystems and production forests, including enhancing yields of crops, forage, and wood; stabilizing yields across time and space; enhancing pollinators and pollination; suppressing weeds and other pests; and ...

  14. Sustainable dryland agroecosystems management

    USDA-ARS?s Scientific Manuscript database

    The Dryland Agroecosystem Project was established in the fall of 1985 with 1986 being the first harvest year. Grain and stover yields, crop residue amounts, soil water measurements, crop management, crop nutrient content and climate data have been reported annually in previously published technical...

  15. Sustainable intensification by managing microbial communities and processes in agroecosystems

    USDA-ARS?s Scientific Manuscript database

    By focusing on soil biology and biochemistry, agroecosystem management strategies are implemented which include reduced soil disturbance, diverse and adaptable crop rotations, retention of residue, and incorporation of livestock, cover crops, or both This systems approach is required to sustainably ...

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

    USDA-ARS?s Scientific Manuscript database

    We propose 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 link is briefly su...

  17. Background antibiotic resistance patterns in antibiotic-free pastured poultry production

    USDA-ARS?s Scientific Manuscript database

    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...

  18. INCORPORATING BATS IN AGROECOSYSTEM MANAGEMENT AND CROP PROTECTION DECISIONS

    EPA Science Inventory

    By characterizing the diet of bats in agroecosystems, this research likely will document that bats are important consumers of pest species. Additionally, this investigation will document which pest species are consumed and the relative contribution of these species to bat d...

  19. Long Term Agroecosystem Research Landing | National Agricultural Library

    Science.gov Websites

    Skip to main content Home National Agricultural Library United States Department of Agriculture Ag Agroecosystem Research Overview Agriculture faces tremendous challenges in meeting multiple, diverse societal > ENVIRONMENTAL ASSESSMENTS filter EARTH SCIENCE > AGRICULTURE > SOILS (1) Apply EARTH

  20. Antibiotics in agroecosystems: Introduction to the special section

    USDA-ARS?s Scientific Manuscript database

    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, ...

  1. Sustainable dryland agroecosystems management

    USDA-ARS?s Scientific Manuscript database

    The Dryland Agroecosystem Project with No-till management was established in the fall of 1985, with 1986 being the first harvest year. Grain and stover yields, crop residue amounts, soil water measurements, crop nutrient content and climate data have been reported annually in previously published t...

  2. Application of Near-Surface Remote Sensing and computer algorithms in evaluating impacts of agroecosystem management on Zea mays (corn) phenological development in the Platte River - High Plains Aquifer Long Term Agroecosystem Research Network field sites.

    NASA Astrophysics Data System (ADS)

    Okalebo, J. A.; Das Choudhury, S.; Awada, T.; Suyker, A.; LeBauer, D.; Newcomb, M.; Ward, R.

    2017-12-01

    The Long-term Agroecosystem Research (LTAR) network is a USDA-ARS effort that focuses on conducting research that addresses current and emerging issues in agriculture related to sustainability and profitability of agroecosystems in the face of climate change and population growth. There are 18 sites across the USA covering key agricultural production regions. In Nebraska, a partnership between the University of Nebraska - Lincoln and ARD/USDA resulted in the establishment of the Platte River - High Plains Aquifer LTAR site in 2014. The site conducts research to sustain multiple ecosystem services focusing specifically on Nebraska's main agronomic production agroecosystems that comprise of abundant corn, soybeans, managed grasslands and beef production. As part of the national LTAR network, PR-HPA participates and contributes near-surface remotely sensed imagery of corn, soybean and grassland canopy phenology to the PhenoCam Network through high-resolution digital cameras. This poster highlights the application, advantages and usefulness of near-surface remotely sensed imagery in agroecosystem studies and management. It demonstrates how both Infrared and Red-Green-Blue imagery may be applied to monitor phenological events as well as crop abiotic stresses. Computer-based algorithms and analytic techniques proved very instrumental in revealing crop phenological changes such as green-up and tasseling in corn. This poster also reports the suitability and applicability of corn-derived computer based algorithms for evaluating phenological development of sorghum since both crops have similarities in their phenology; with sorghum panicles being similar to corn tassels. This later assessment was carried out using a sorghum dataset obtained from the Transportation Energy Resources from Renewable Agriculture Phenotyping Reference Platform project, Maricopa Agricultural Center, Arizona.

  3. Upland and in-stream controls on baseflow nutrient dynamics in tile-drained agroecosystem watersheds

    USDA-ARS?s Scientific Manuscript database

    Controls on baseflow nutrient concentrations in agroecosystems are poorly characterized in comparison with storm events. However, in landscapes with low residence times (e.g., rivers and reservoirs), baseflow nutrient concentration dynamics during sensitive timeframes can drive deleterious environm...

  4. Long term agro-ecosystem research: The Southern Plains partnership

    USDA-ARS?s Scientific Manuscript database

    The USDA Agricultural Research Service (ARS) is coordinating ten well-established research sites as a Long Term Agro-ecosystem Research (LTAR) Network. The goal of the LTAR is to sustain a land-based infrastructure for research, environmental management testing, and education, that enables understan...

  5. Intensified agroecosystems and changes in soil carbon dynamics

    USDA-ARS?s Scientific Manuscript database

    Land use change, intensive farming systems and poor land management practices can reduce soil organic carbon (SOC) and soil health. One way to address these concerns is by increasing ecological intensification in agroecosystems for environmental and economic benefits. This chapter will discuss the b...

  6. Landuse and agricultural management practice web-service (LAMPS) for agroecosystem modeling and conservation planning

    USDA-ARS?s Scientific Manuscript database

    Agroecosystem models and conservation planning tools require spatially and temporally explicit input data about agricultural management operations. The USDA Natural Resources Conservation Service is developing a Land Management and Operation Database (LMOD) which contains potential model input, howe...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  8. Reconciling opposing soil processes in row-crop agroecosystems via soil functional zone management

    USDA-ARS?s Scientific Manuscript database

    Sustaining soil productivity in agroecosystems presents a fundamental ecological challenge: nutrient provisioning depends upon aggregate turnover and microbial decomposition of organic matter (SOM); yet to prevent soil depletion these processes must be balanced by those that restore nutrients and SO...

  9. POPULATION DYNAMICS OF AMBIENT AND ALTERED EARTHWORM COMMUNITIES IN ROW-CROP AGROECOSYSTEMS IN OHIO, USA

    EPA Science Inventory

    Although earthworms are known to influence agroecosystem processes, there are relatively few long-term studies addressing population dynamics under cropping systems in which earthworm populations were intentionally altered. We assessed earthworm communities from fall 1994 to spr...

  10. Factors Affecting Soil Microbial Community Structure in Tomato Cropping Systems

    USDA-ARS?s Scientific Manuscript database

    Soil and rhizosphere microbial communities in agroecosystems may be affected by soil, climate, plant species, and management. We identified some of the most important factors controlling microbial biomass and community structure in an agroecosystem utilizing tomato plants with the following nine tre...

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

    NASA Astrophysics Data System (ADS)

    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 of C/m2, respectively). In the contaminated soils, it was higher under the potato monoculture and reached -41 g of C/m2.

  12. Increasing diveristy of arbuscular mycorrhizal fungi in agroecosystems using specific cover crops

    USDA-ARS?s Scientific Manuscript database

    Fall-planted cover crops provide a plant host for obligate symbiotic arbuscular mycorrhizal fungi (AMF) during otherwise fallow periods and thus may increase AMF numbers in agroecosystems. Increased AMF numbers should increase mycorrhizal colonization of the subsequent cash crops, which has been li...

  13. Soil fungal community and fuctional diversity assessments of agroecosystems in the Southern High Plains

    USDA-ARS?s Scientific Manuscript database

    Soil fungi perform a variety of ecosystem functions that are crucial to maintaining agroecosystem sustainability including aggregate stability and soil carbon storage. The purpose of this study was to compare soil fungal communities and functional diversity in integrated crop and livestock (ICL) sy...

  14. Perspectives on the developing common experiment across the 18 sites within the long term agroecosystem research network

    Treesearch

    Kris Havstad

    2016-01-01

    The USDA Agricultural Research Service (ARS) established a Long Term Agroecosystem Research Network (LTAR) across 10 of its research locations, including some of its large watershed facilities, in 2012 and expanded that network to 18 locations in 2014.

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

    USDA-ARS?s Scientific Manuscript database

    Cumulative nitrous oxide (N2O) emissions calculated from discrete chamber-based flux measurements have unknown uncertainty. This study used an agroecosystems simulation model to design sampling strategies that yield accurate cumulative N2O flux estimates with a known uncertainty level. Daily soil N2...

  16. An "Information Ecosystem" to meet the data requirements of the Long-Term Agroecosystem Research (LTAR)

    USDA-ARS?s Scientific Manuscript database

    USDA’s Long-Term Agroecosystem Research (LTAR) Network consists of 18 locations across the continental United States comprised of government, university and NGO supported sites. LTAR research on the sustainability of agricultural production and associated provision of ecosystem services relies upon ...

  17. Antibiotics in agroecosystems: state of the science “ARASOS” workshop summary

    USDA-ARS?s Scientific Manuscript database

    In August 2014, the Biosphere2 Conference Center in Oracle, Arizona was the site of a sunny three-day workshop on “Antibiotics in Agroecosystems: State of the Science.” Attended by 42 people, participants included scientists and others from academia, government agencies (including EPA and USDA), an...

  18. Nitrous oxide emissions from intensively managed agroecosystems: The role of carbon inputs

    USDA-ARS?s Scientific Manuscript database

    In agroecosystems, many reports demonstrate a positive relationship between N2O emissions and N fertilizer inputs. This relationship has been incorporated into IPCC model estimates of N2O emissions and implies that inorganic N limits N2O emissions. However, evidence indicates that denitrification ac...

  19. Integrating legacy data to understand agroecosystem regional dynamics to catastrophic events

    USDA-ARS?s Scientific Manuscript database

    Multi-year extreme drought events are part of the history of the Earth system. Legacy data on the climate drivers, geomorphic features, and agroecosystem responses across a dynamically changing landscape throughout a region can provide important insights to a future where large-scale catastrophic ev...

  20. Relative dispersal ability of a key agricultural pest and its predators in an annual agroecosystem

    USDA-ARS?s Scientific Manuscript database

    In annual agroecosystems staggered planting dates, pesticide treatments, and harvesting events create a “shifting mosaic” of habitats that leads to frequent recolonization by herbivores and natural enemies. In these systems, an untested assumption is that herbivores have higher rates of dispersal re...

  1. [Environmental quality assessment of regional agro-ecosystem in Loess Plateau].

    PubMed

    Wang, Limei; Meng, Fanping; Zheng, Jiyong; Wang, Zhonglin

    2004-03-01

    Based on the detection and analysis of the contamination status of agro-ecosystem with apple-crops intercropping as the dominant cropping model in Loess Plateau, the individual factor and comprehensive environmental quality were assessed by multilevel fuzzy synthetic evaluation model, analytical hierarchy process(AHP), and improved standard weight deciding method. The results showed that the quality of soil, water and agricultural products was grade I, the social economical environmental quality was grade II, the ecological environmental quality was grade III, and the comprehensive environmental quality was grade I. The regional agro-ecosystem dominated by apple-crops intercropping was not the best model for the ecological benefits, but had the better social economical benefits.

  2. Long-Term Agroecosystem Research Advancing Sustainable Intensification in Fields, Farms, and Regions Across the United States

    USDA-ARS?s Scientific Manuscript database

    The Long-Term Agroecosystem Research network is building a road map for the sustainable intensification of U.S. agriculture by designing strategies that are locally appropriate and applicable to multiple scales of agricultural organization. The 18 sites in the LTAR network represent a diversity of l...

  3. Modeling denitrification in a tile-drained, corn and soybean agroecosystem of Illinois, USA

    USDA-ARS?s Scientific Manuscript database

    Denitrification is known as an important pathway for nitrate loss in agroecosystems. It is important to estimate denitrification fluxes to close field and watershed N mass balances, determine greenhouse gas emissions (N2O), and help constrain estimates of other major N fluxes (e.g., nitrate leaching...

  4. Long-term agro-ecosystem research or the southern great plains: The USDA-ARS Grazinglands Research Laboratory partnership

    USDA-ARS?s Scientific Manuscript database

    The USDA Agricultural Research Service (ARS) is coordinating ten well-established research sites as a Long-Term Agro-ecosystem Research (LTAR) Network. The goal of the LTAR is to sustain a land-based infrastructure for research, environmental management testing, and education, that enables understan...

  5. Underestimation of simulated N2O flux in a model comparison of DayCent, DNDC, and EPIC

    USDA-ARS?s Scientific Manuscript database

    Process-based models are increasingly used as tool for studying complex agroecosystem interactions N2O emissions from agricultural fields. The widespread use of these models to conduct research and inform policy benefits from periodic model comparisons that assess the state of agroecosystem modeling...

  6. Comparing Energy Use and Efficiency in Central Iowa Agroecosystems

    ERIC Educational Resources Information Center

    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…

  7. Choosing natural enemies for conservation biological control: use of the prey detectability half-life to rank agroecosystem predators

    USDA-ARS?s Scientific Manuscript database

    Agroecosystems are speciose, making selection of natural enemies for conservation biological control non-trivial. Molecular gut analysis enables ranking of predators by the incidence of pest remains in the gut. However, predators differ in digestive rates, and ranking by incidence favors those with ...

  8. Identifying challenges and opportunities for improved nutrient management through U.S.D.A's Dairy Agroecosystem Working Group

    USDA-ARS?s Scientific Manuscript database

    Nutrient management is a priority of U.S. dairy farms, although specific concerns vary across regions and management systems. To elucidate challenges and opportunities to improving nutrient use efficiencies, the USDA’s Dairy Agroecosystems Working Group investigated 10 case studies of confinement (i...

  9. Sustainable intensification of U.S. agriculture: Aspirations and barriers in the regional agroecosystems of the LTAR network

    USDA-ARS?s Scientific Manuscript database

    The sustainable intensification of agriculture in the United States will require major shifts in producer decision-making, markets, and public policies. The Long-Term Agroecosystem Research (LTAR) network is working to better understand how these shifts may be accomplished. Through a common experime...

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2017-04-01

    Agricultural crop production is to a great extent determined by weather conditions. The research hypothesis is that meteorological risks act as drivers of environmental innovation in agro-ecosystem management. The methodology comprised five major parts: 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 resulted in spatial temperature extremes, precipitation deficits and wet periods. The temporal overlap between extreme weather conditions and sensitive periods in the agro-ecosystem was realised using a bio-physically based modelling framework that couples phenology, a soil water balance and crop growth. 20-year return values for drought and waterlogging during different crop stages were related to arable yields. The method helped quantify agricultural production risks and rate both weather and crop-based agricultural insurance. The spatial extent of vulnerability is developed on different layers of geo-information to include meteorology, soil-landscapes, crop cover and management. Vulnerability of agroecosystems was mapped based on rules set by experts' knowledge and implemented by Fuzzy Inference System modelling and Geographical Information System tools. The approach was applied for cropland vulnerability to heavy rain and grassland vulnerability to drought. The level of vulnerability and resilience of an agro-ecosystem was also determined by risk management which differed across sectors and farm types. A calibrated agro-economic model demonstrated a marked influence of climate adapted land allocation and crop management on individual utility. The "chain of risk" approach allowed for investigating the hypothesis that meteorological risks act as drivers for agricultural innovation. Risk types were quantified in terms of probability and distribution, and further distinguished according to production type. Examples of strategies and options were provided at field, farm and policy level using different modelling methods.

  15. The MERINOVA project: MEteorological RIsks as drivers of environmental inNOvation in Agro-ecosystem management

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Devastating weather-related events have captured the interest of the general public in Belgium. Extreme weather events such as droughts, heat waves and rain storms are projected to increase both in frequency and magnitude with climate change. Since more than half of the Belgian territory is managed by the agricultural sector, extreme events may have significant impacts on agro-ecosystem services and pose severe limitations to sustainable agricultural land management. The research hypothesis of the MERINOVA project is that meteorological risks act as drivers of environmental innovation in agro-ecosystem management. The major objectives are to characterise extreme meteorological events, assess the impact on Belgian agro-ecosystems, characterise their vulnerability and resilience to these events, and explore innovative adaptation options to agricultural risk management. 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. Impacts developed from physically based models not only provide information on the state of the damage at any given time, but also assist in understanding the links between different factors causing damage and determining bio-physical vulnerability. Socio-economic impacts enlarge the basis for vulnerability mapping, risk management and adaptation options. The perspective of rising risk-exposure is exacerbated further by more limits to aid received for agricultural damage and an overall reduction of direct income support to farmers. The main findings of each of these project building blocks will be communicated. MERINOVA provides for a robust and flexible framework by demonstrating its performance across Belgian agro-ecosystems, and by ensuring its relevance to policy makers and practitioners. A strong expert and end-user network is established to help disseminating and exploiting project results to meet user needs. The research is funded by the Belgian Science Policy Organisation (Belspo) under contract nr SD/RI/03A. https://merinova.vito.be

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

    USDA-ARS?s Scientific Manuscript database

    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...

  17. Influence of Tillage, Cropping Management, and Nitrogen Source on Humic, Fulvic, and Water-Extractable Organic Matter Fractions: A Fluorescence Study

    USDA-ARS?s Scientific Manuscript database

    The characterization of organic matter in agroecosystems is important due to its involvement in many soil ecosystem processes. Humic acid, fulvic acid, and water-extractable organic matter from a nine-year agroecosystem study investigating the effects of tillage, cropping system, and N source were c...

  18. The AgroEcoSystem (AgES) response-function model simulates layered soil water dynamics in semi-arid Colorado: sensitivity and calibration

    USDA-ARS?s Scientific Manuscript database

    Simulation of vertical soil hydrology is a critical component of simulating even more complex soil water dynamics in space and time, including land-atmosphere and subsurface interactions. The AgroEcoSystem (AgES) model is defined here as a single land unit implementation of the full AgES-W (Watershe...

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

    USDA-ARS?s Scientific Manuscript database

    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 fou...

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

    Treesearch

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

    2017-01-01

    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 (...

  1. Simulating the dynamics of linear forests in great plains agroecosystems under changing climates

    Treesearch

    Qinfeng Guo; J. Brandle; Michele Schoeneberger; D. Buettner

    2004-01-01

    Most forest growth models are not suitable for the highly fragmented, linear (or linearly shaped) forests in the Great Plains agroecosystems (e.g., windbreaks, riparian forest buffers), where such forests are a minor but ecologically important component of the land mosaics. This study used SEEI)SCAPE, a recently modified gap model designed for cultivated land mosaics...

  2. Dynamics of an island agroecosystem: Where to now?

    Treesearch

    Marjorie V. C. Falanruw;  Francis Ruegorong

    2015-01-01

    This chapter describes past interaction of human populations with habitats on mainland Yap and the dynamics of the agroecosystem that developed. Recent changes in this system on mainland Yap are described, followed by a description of the nature and threats to agriculture in the Outer Islands. The chapter concludes by asking “Where to now?” and considers a past...

  3. Effects of synthetic fertilizer on coffee yields and ecosystem services: Soil glomalin and parasitoids in a Costa Rican coffee agroecosystem

    USDA-ARS?s Scientific Manuscript database

    We explored the relationships between synthetic fertilizer use, yield, and ecosystem services in a coffee agroecosystem in the Tarrazú region in the central highlands of Costa Rica. Working in nine farms ranging from 0.3 to 2.7ha in the CoopeTarrazú farmers' cooperative, we focused on two important ...

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

    NASA Astrophysics Data System (ADS)

    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 provides for a robust and flexible framework by demonstrating its performance across Belgian agro-ecosystems, and by ensuring its relevance to policy makers and practitioners. A strong expert and end-user network is established to help disseminate and exploit project results to meet user needs.

  5. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Solomon, D.; Lehmann, J; Kinyangi, J

    The soil environment is a primary component of the global biogeochemical sulfur (S) cycle, acting as a source and sink of various S species and mediating oxidation state changes. However, ecological significance of the various S forms and the impacts of human intervention and climate on the amount and structural composition of these compounds are still poorly understood. We investigated the long-term influences of anthropogenically mediated transitions from natural to managed ecosystems on molecular-level speciation, biogeochemical dynamics, and the apparent temperature sensitivity of S moieties in temperate, subtropical, and tropical environments with mean annual temperature (MAT) ranging from 5C tomore » 21C, using elemental analysis and X-ray absorption near-edge structure (XANES) spectroscopy. Land-use and land-cover changes led to the depletion of total soil S in all three ecoregions over a period of up to 103 years. The largest decline occurred from tropical forest agroecosystems (67% Kakamega and 76% Nandi, Kenya), compared to losses from temperate (36% at Lethbridge, Canada, and 40% at Pendleton, USA) and subtropical (48% at South Africa) grassland agroecosystems. The total S losses correlated significantly with MAT. Anthropogenic interventions profoundly altered the molecular-level composition and resulted in an apparent shift in oxidation states of organic S from native ecosystems composed primarily of S moieties in intermediate and highly reduced oxidation states toward managed agroecosystems dominated by organic S rich in strongly oxidized functionalities. The most prominent change occurred in thiols and sulfides, the proportion of which decreased by 46% (Lethbridge) and 57% (Pendleton) in temperate agroecosystems, by 46% in subtropical agroecosystems, and by 79% (Nandi) and 81% (Kakamega) in tropical agroecosystems. The proportion of organic S directly linked to O increased by 81%, 168%, 40%, 92%, and 85%, respectively. Among the various organic S functionalities, thiols and sulfides seem to have higher apparent temperature sensitivity, and thus these organic S moieties may become prone to losses due to land-use changes, even from the cooler regions of the world if MAT of these regions rise in the future.« less

  6. The Long-Term Agro-Ecosystem Research (LTAR) Network: A New In-Situ Data Network For Agriculture

    NASA Astrophysics Data System (ADS)

    Walbridge, M. R.

    2014-12-01

    Agriculture in the 21st Century faces significant challenges due to increases in the demand for agricultural products from a global population expected to reach 9.5 billion by 2050, changes in land use that are reducing the area of arable land worldwide, and the uncertainties associated with increasing climate variability and change. There is broad agreement that meeting these challenges will require significant changes in agro-ecosystem management at the landscape scale. In 2012, the USDA/ARS announced the reorganization of 10 existing benchmark watersheds, experimental ranges, and research farms into a Long-Term Agro-ecosystem Research (LTAR) network. Earlier this year, the LTAR network expanded to 18 sites, including 3 led by land grant universities and/or private foundations. The central question addressed by the LTAR network is, "How do we sustain or enhance productivity, profitability, and ecosystem services in agro-ecosystems and agricultural landscapes"? All 18 LTAR sites possess rich historical databases that extend up to 100 years into the past. However as LTAR moves forward, the focus is on collecting a core set of common measurements over the next 30-50 years that can be used to draw inferences regarding the nature of agricultural sustainability and how it varies across regional and continental-scale gradients. As such, LTAR is part long-term research network and part observatory network. Rather than focusing on a single site, each LTAR has developed regional partnerships that allow it to address agro-ecosystem function in the large basins and eco-climatic zones that underpin regional food production systems. Partners include other long-term in-situ data networks (e.g., Ameriflux, CZO, GRACEnet, LTER, NEON). 'Next steps' include designing and implementing a cross-site experiment addressing LTAR's central question.

  7. A dynamic life table model of Psorophora columbiae in the southern Louisiana rice agroecosystem with supporting hydrologic submodel. Part 1. Analysis of literature and model development.

    PubMed

    Focks, D A; McLaughlin, R E; Smith, B M

    1988-09-01

    During the past decade, the rice agroecosystem and its associated mosquitoes have been the subject of an extensive research effort directed toward the development and implementation of integrated pest management (IPM) strategies. The objective of this work was to synthesize the literature and unpublished data on the rice agroecosystem into a comprehensive simulation model of the key elements of the system known to influence the population dynamics of Psorophora columbiae. Subsequent companion papers will present a validation of these models, provide an in-depth analysis of the population dynamics of Ps. columbiae, and evaluate current and proposed IPM strategies for this mosquito. This paper describes the development of 2 models: WaterMod: Because spatial and temporal distributions of surface water and soil moisture play a decisive role in the dynamics of Ps. columbiae, an essentially hydrological simulator was developed. Its purpose is to provide environmental inputs for a second model (PcSim) which simulates the population dynamics of Ps. columbiae. WaterMod utilizes data on weather, agricultural practices, and soil characteristics for a particular region to generate a data set containing daily estimates of soil moisture and depth of water table for 12 representative areas comprising the rice agroecosystem. This model could be used to provide hydrologic inputs for additional simulation models of other riceland mosquito species. PcSim: This model simulates the population dynamics of Ps. columbiae by using the computer to maintain a daily accounting of the absolute number of mosquitoes within each daily age class for each life stage. The model creates estimates of the number of eggs, larvae, pupae, and adults for a representative l-ha area of a rice agroecosystem.

  8. Mapping agroecosystem zone using remote sensing for food security analysis in Bantul district Daerah Istimewa Yogyakarta

    NASA Astrophysics Data System (ADS)

    Murti, Sigit Heru

    2017-10-01

    Food security is one of the most important issue for Indonesia. The huge population number and high population growing rate has made the food security a critical issue. This paper describe the application of remote sensing data to (1) map agroecosystem zones in Bantul District, Special Region of Yogyakarta, Indonesia in 2012 and (2) analyze the food security in the study area based on the resulting agro-ecosystem map. Bantul District is selected as the pilot area because this area is among the highest food crop production area in the Province. ALOS AVNIR-2 image accquired on 15 June 2010 was integrated with Indonesian Surface map (RBI map), soil types map, and slope steepness map. Population statistics data was also used to calculate the food needs. Field survey was conducted to obtain the crop field productivity information on each agro-ecosystem zone and assess the accuracy of the model. This research indicates that (1) Bantul District can be divided into three agroecosystem zones, where each zone has unique topograhic configuration and soil types composition, and (2) Bantul Distict is categorized as food secure area since the rice production in 2012 managed to cover the food needs of the people with the surplus of 33,208.6 tonnes of rice. However, when the analysis was conducted at sub-district level, there are four subdistrict with food insecurity where the food needs surpass the rice production. These sub-district are Kasihan Sub-district (-5,598.4 t), Banguntapan Sub-district (-2,483.4 t), Pajangan Sub-district (-1,039.6 t) and Dlingo Sub-district (-798.7 t).

  9. Carbon balance assessment by eddy covariance method for agroecosystems with potato plants and oats & vetch mixture on sod-podzolic soils of Russia

    NASA Astrophysics Data System (ADS)

    Meshalkina, J. L.; Yaroslavtsev, A. M.; Vasenev, I. I.; Andreeva, I. V.; Tihonova, M. V.

    2018-01-01

    The carbon balance for the agroecosystems with potato plants and oats & vetch mixture on sod-podzolics soils was evaluated using the eddy covariance approach. Absorption of carbon was recorded only during the growing season; maximum values were detected for all crops in July. The number of days during the vegetation period, when the carbon stocked in the fields with potatoes and oats & vetch mixture was about the same and accounted for 53-55 days. During this period, the increase in gross primary production (GPP) is well correlated with the crop yields. The curve of the gross primary productivity is closely linked to the phases of development of plants; for potatoes, this graph differs significantly for all phases. Form of oats & vetch mixture biomass curve shown linear increases. Carbon losses were observed for all the studied agroecosystems: for fields with an oats & vetch mixture they were 254 g C m-2 y-1, while for fields with potato plants they were 307 g C m-2 y-1. Values about 250-300 g C m-2 per year may be considered as estimated values for the total carbon uptake for agroecosystems with potato plants and oats & vetch mixture on sod-podzolic soils.

  10. Long-term Agroecosystem Research in the Northern Great Plains.

    NASA Astrophysics Data System (ADS)

    Schmer, M.; Sanderson, M.; Liebig, M. A.; Wienhold, B.; Awada, T.; Papiernik, S.; Osborne, S.; Kemp, W.; Okalebo, J. A.; Riedall, W.

    2015-12-01

    The Northern Great Plains is the bread basket of the United States, accounting for a substantial portion of U.S. agricultural production. This region faces critical challenges regarding balancing food needs, resource conservation (e.g Ogallala aquifer), environmental concerns, and rural economy development. Developing transformative, multifunctional systems will require equally imaginative and efficient tools to help farmers manage complex agroecosystems in a rapidly changing climate. The Northern Plains long-term agroecosystem research (LTAR) site at Mandan, ND and the Platte River High Plains LTAR (ARS/University of Nebraska-Lincoln) at Lincoln, NE in collaboration with USDA-ARS research units in Brookings, SD and Fargo, ND are collaborating to address the grand challenge of providing and sustaining multiple service provisions from Northern Great Plains agroecosystems. We propose to attain these goals through sustainable intensification based on the adoption of conservation agriculture principles including reduced soil disturbance, livestock integration, and greater complexity and diversity in the cropping system. Here, we summarize new concepts these locations have pioneered in dynamic cropping systems, resource use efficiency, and agricultural management technologies. As part of the LTAR network, we will conduct long-term cross-site research to design and assess new agricultural practices and systems aimed at improving our understanding of decision making processes and outcomes across an array of agricultural systems.

  11. Development of an integrated generic model for multi-scale assessment of the impacts of agro-ecosystems on major ecosystem services in West Africa.

    PubMed

    Belem, Mahamadou; Saqalli, Mehdi

    2017-11-01

    This paper presents an integrated model assessing the impacts of climate change, agro-ecosystem and demographic transition patterns on major ecosystem services in West-Africa along a partial overview of economic aspects (poverty reduction, food self-sufficiency and income generation). The model is based on an agent-based model associated with a soil model and multi-scale spatial model. The resulting Model for West-Africa Agro-Ecosystem Integrated Assessment (MOWASIA) is ecologically generic, meaning it is designed for all sudano-sahelian environments but may then be used as an experimentation facility for testing different scenarios combining ecological and socioeconomic dimensions. A case study in Burkina Faso is examined to assess the environmental and economic performances of semi-continuous and continuous farming systems. Results show that the semi-continuous system using organic fertilizer and fallowing practices contribute better to environment preservation and food security than the more economically performant continuous system. In addition, this study showed that farmers heterogeneity could play an important role in agricultural policies planning and assessment. In addition, the results showed that MOWASIA is an effective tool for designing, analysing the impacts of agro-ecosystems. Copyright © 2017. Published by Elsevier Ltd.

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

    PubMed

    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.

  13. [Research progress and trend on grassland agroecology].

    PubMed

    Ren, Jizhou; Li, Xianglin; Hou, Fujiang

    2002-08-01

    The connotation, progress, research frontiers and developmental trend of grassland agroecology are discussed in this paper. The interface theory, structure and function, coupling and discordance, and health assessment of grassland agroecosystems were recognized as the four research frontiers of the discipline. There exist three primary interfaces in a grassland agroecosystem, i.e., vegetation-site, grassland-animal and production-management. Research into a series of the ecological processes that occurred at these interfaces is the key to revealing the features of the system behavior. There are four sections in a grassland agroecosystem, i.e., pre-plant, plant, animal and post-biotic sections. System coupling and discordance are the two important concepts to describe interactions among the production sections. System coupling among the sections can lead to system improvement by exerting the potential of system capacity. Health of an ecosystem is a reflection of its structure and function, and health assessment is a measurement of its orderliness and service value.

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

    PubMed

    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 sensitive, changes in microbial biomass, activity, and community structure as a result of increased metal concentration in soil may be used as indicators of soil contamination or soil environmental quality. Future research needs to focus on the balance of trace elements in an agroecosystem, elaboration of soil chemical and biochemical parameters that can be used to diagnose soil contamination with or deficiency in trace elements, and quantification of trace metal transport from an agroecosystem to the environment.

  15. Determination of nitrogen balance in agroecosystems.

    PubMed

    Sainju, Upendra M

    2017-01-01

    Nitrogen balance in agroecosystems provides a quantitative framework of N inputs and outputs and retention in the soil that examines the sustainability of agricultural productivity and soil and environmental quality. Nitrogen inputs include N additions from manures and fertilizers, atmospheric depositions including wet and dry depositions, irrigation water, and biological N fixation. Nitrogen outputs include N removal in crop grain and biomass and N losses through leaching, denitrification, volatilization, surface runoff, erosion, gas emissions, and plant senescence. Nitrogen balance, which is the difference between N inputs and outputs, can be reflected in changes in soil total (organic + inorganic) N during the course of the experiment duration due to N immobilization and mineralization. While increased soil N retention and mineralization can enhance crop yields and decrease N fertilization rate, reduced N losses through N leaching and gas emissions (primarily NH 4 and NO x emissions, out of which N 2 O is a potent greenhouse gas) can improve water and air quality. •This paper discusses measurements and estimations (for non-measurable parameters due to complexity) of all inputs and outputs of N as well as changes in soil N storage during the course of the experiment to calculate N balance.•The method shows N flows, retention in the soil, and losses to the environment from agroecosystems.•The method can be used to measure agroecosystem performance and soil and environmental quality from agricultural practices.

  16. Spider diversity in coffee agroecosystems: the influence of agricultural intensification and aggressive ants.

    PubMed

    Marín, Linda; Perfecto, Ivette

    2013-04-01

    Spiders are a very diverse group of invertebrate predators found in agroecosystems and natural systems. However, spider distribution, abundance, and eventually their ecological function in ecosystems can be influenced by abiotic and biotic factors such as agricultural intensification and dominant ants. Here we explore the influence of both agricultural intensification and the dominant arboreal ant Azteca instabilis on the spider community in coffee agroecosystems in southern Mexico. To measure the influence of the arboreal ant Azteca instabilis (F. Smith) on the spider community inhabiting the coffee layer of coffee agroecosystems, spiders were collected from coffee plants that were and were not patrolled by the ant in sites differing in agricultural intensification. For 2008, generalized linear mixed models showed that spider diversity was affected positively by agricultural intensification but not by the ant. However, results suggested that some spider species were associated with A. instabilis. Therefore, in 2009 we concentrated our research on the effect of A. instabilis on spider diversity and composition. For 2009, generalized linear mixed models show that spider richness and abundance per plant were significantly higher in the presence of A. instabilis. In addition, analyses of visual counts of insects and sticky traps data show that more resources were present in plants patrolled by the ant. The positive effect of A. instabilis on spiders seems to be caused by at least two mechanisms: high abundance of insects and protection against predators.

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

    PubMed

    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'. © 2016 The Author(s).

  18. Agroecology and the Sustainable Production of Food and ...

    EPA Pesticide Factsheets

    The silvopastoral, agricultural system of the montado in Southern Portugal is an example of the self-organization of an agroecological system adapted to the climate and soil conditions of the Mediterranean basin. This system with its consistent production of food, fiber, and ecosystem services along with its concomitant rural social organization has been sustained in the region for over 1000 years. However, the system has been gradually decreasing in extent since the 19th century and its rate of decline has accelerated since the 1980s. The causes of this decline have been traced in descending order of importance to land managment choices, spatial factors and environmental factors. In addition, past studies have shown that there is an optimum livestock support capacity for maintaining the health of the montado agroecosystem. In this study, we used the results of an emergy evaluation of a cattle farm as part of a montado agroecosystem to examine the effects of the European Union’s (EU) Common Agricultural Policy (CAP) on the viability of both cattle rearing and the long term regional sustainability of montado agroecosystems. We found that the CAP and its two pillars for providing subsidies, (1) Common Market Organization (CMO) and (2) Rural Development Policy (RDP) are complex and take into account many aspects of prices and markets for particular products, e.g., beef and veal (CMO) and sustainable rural development, e.g., silvopastoral agroecosystems (RDP). How

  19. Evolution in agriculture: the application of evolutionary approaches to the management of biotic interactions in agro-ecosystems

    PubMed Central

    Thrall, Peter H; Oakeshott, John G; Fitt, Gary; Southerton, Simon; Burdon, Jeremy J; Sheppard, Andy; Russell, Robyn J; Zalucki, Myron; Heino, Mikko; Ford Denison, R

    2011-01-01

    Anthropogenic impacts increasingly drive ecological and evolutionary processes at many spatio-temporal scales, demanding greater capacity to predict and manage their consequences. This is particularly true for agro-ecosystems, which not only comprise a significant proportion of land use, but which also involve conflicting imperatives to expand or intensify production while simultaneously reducing environmental impacts. These imperatives reinforce the likelihood of further major changes in agriculture over the next 30–40 years. Key transformations include genetic technologies as well as changes in land use. The use of evolutionary principles is not new in agriculture (e.g. crop breeding, domestication of animals, management of selection for pest resistance), but given land-use trends and other transformative processes in production landscapes, ecological and evolutionary research in agro-ecosystems must consider such issues in a broader systems context. Here, we focus on biotic interactions involving pests and pathogens as exemplars of situations where integration of agronomic, ecological and evolutionary perspectives has practical value. Although their presence in agro-ecosystems may be new, many traits involved in these associations evolved in natural settings. We advocate the use of predictive frameworks based on evolutionary models as pre-emptive management tools and identify some specific research opportunities to facilitate this. We conclude with a brief discussion of multidisciplinary approaches in applied evolutionary problems. PMID:25567968

  20. Nitrogen gas emissions and nitrate leaching dynamics under different tillage practices based on data synthesis and process-based modeling

    NASA Astrophysics Data System (ADS)

    Huang, Y.; Ren, W.; Tao, B.; Zhu, X.

    2017-12-01

    Nitrogen losses from the agroecosystems have been of great concern to global changes due to the effects on global warming and water pollution in the form of nitrogen gas emissions (e.g., N2O) and mineral nitrogen leaching (e.g., NO3-), respectively. Conservation tillage, particularly no-tillage (NT), may enhance soil carbon sequestration, soil aggregation and moisture; therefore it has the potential of promoting N2O emissions and reducing NO3- leaching, comparing with conventional tillage (CT). However, associated processes are significantly affected by various factors, such as soil properties, climate, and crop types. How tillage management practices affect nitrogen transformations and fluxes is still far from clear, with inconsistent even opposite results from previous studies. To fill this knowledge gap, we quantitatively investigated gaseous and leaching nitrogen losses from NT and CT agroecosystems based on data synthesis and an improved process-based agroecosystem model. Our preliminary results suggest that NT management is more efficient in reducing NO3- leaching, and meanwhile it simultaneously increases N2O emissions by approximately 10% compared with CT. The effects of NT on N2O emissions and NO3- leaching are highly influenced by the placement of nitrogen fertilizer and are more pronounced in humid climate conditions. The effect of crop types is a less dominant factor in determining N2O and NO3- losses. Both our data synthesis and process-based modeling suggest that the enhanced carbon sequestration capacity from NT could be largely compromised by relevant NT-induced increases in N2O emissions. This study provides the comprehensive quantitative assessment of NT on the nitrogen emissions and leaching in agroecosystems. It provides scientific information for identifying proper management practices for ensuring food security and minimizing the adverse environmental impacts. The results also underscore the importance of suitable nitrogen management in the NT agroecosystems for climate adaptation and mitigation.

  1. [Trophic ecology in tadpoles of Rhinella arenarum (Anura: Bufonidae) in agroecosystems and their possible implications for conservation].

    PubMed

    Bionda, Clarisa; Gari, Noemi; Luque, Elisa; Salas, Nancy; Lajmanovich, Rafael; Martino, Adolfo

    2012-06-01

    The progress of the agriculture border has led an important loss of natural habitats, with significant consequences for biodiversity. In this sense, the studies in 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 body condition and diet in Rhinella arenarum, tadpoles, an anuran species widely distributed in South America and that inhabit agroecosystems. Three sites were sampled, two agroecosystems with different alteration degrees (C1 and C2) and an uncultured (SM) third place. The captured tadpoles were anesthetized, fixed and preserved in formaldehyde (10%). Subsequently, body measurements were made and the complete intestine was removed and analyzed for food items under a binocular microscope. The diet in R. arenarum tadpoles has a dominance of algae Bacillariophyceae, followed by Cyanophyceae. In particular, the class Bacillariophyceae, due to the presence of the genus Navicula, Nitzschia, Gomphonema and Hantzschia, was important in the diet of the anurans in those agroecosystems. Class Cyanophyceae, mainly represented by genus Oscillatoria and Euglenophyceae represented by Euglena and Strombomonas, were predominant in the diet of the anurans in SM. Some differences in the total items consumed by tadpole were observed between the studied sites. Tadpoles that inhabit the modified sites (C1 and C2) recorded a significantly smaller amount of food. Moreover, the tadpoles that inhabit these sites showed a lower body condition. The presence of certain algae associated with eutrophic environments, could indicate some pollution in agroecosystems (C1 and C2). Food resources would be lesser in places with strong agricultural activity, possibly with a greater degree of eutrophication. A smaller food amount could have consequences at population level for the short and long time terms, because of its impact on individual growth. Larval diet is suggested as a potential bioindicator of environmental health for these areas.

  2. Hydroclimatic Controls on Agroecosystem Resiliency in the Northern High Plains

    NASA Astrophysics Data System (ADS)

    Munoz-Arriola, F.; Amaranto, A.; Solomatine, D.; Corzo, G.

    2016-12-01

    Water-controlled ecosystems play a critical role in sustaining intensive food production. More frequent and intense droughts and extreme precipitation challenge genetic progresses to increase crop yields. This work aims to identify the agroecosystem's resiliency to droughts and extreme precipitation in the Northern High Plains (NHP). NHP is characterized by its extensive use of groundwater to fulfill crop irrigation requirements. Groundwater "subsidizes" water deficits and supports intensification of crop production. However, it is unclear how sensitive are agroecosystems to hydroclimatological variations at large-scale, which may affect water discharge and recharge at basin scale and crop production at field scale. Our objective is to develop diagnostic and prognostic conceptual models for groundwater withdrawals in response to climate variability and consumptive use of water. The present study is located in the irrigated agricultural areas of the NHP. We use observed changes in the water table as tracers to changes natural forcing (i.e. observed precipitation) and anthropogenic water demands (i.e. simulated evapotranspiration) though the development of two different diagnostic/prognostic models using Artificial Neural Network (ANN) and Support Vector Machine (SVM). Water-table data was obtained from the Nebraska Geological Survey, and gridded daily hydroclimatic data from Livneh et al (2015), which together with MODIS-LAI provided the inputs for a Variable Infiltration Capacity model to simulate evapotranspiration at a 1/16th degree resolution. A regionalization procedure based on K-Clustering was applied to precipitation data (1950-2013) to identify areas of common and natural variability. Inconsistent output and input sampling frequencies used a time adaptation algorithm to assist the training of the ANN and SVM models. Results showed that both the ANN and the SVM diagnose and predicted ground water. Selected dry and wet (identified Extreme-Precipitation-Event) years are evaluated to isolate hydroclimate and water management drivers and resilient agroecosystems. This methodology will contribute to identify areas of physical vulnerability and agroecosystem resiliency.

  3. MERINOVA: Meteorological risks as drivers of environmental innovation in agro-ecosystem management

    NASA Astrophysics Data System (ADS)

    Gobin, Anne; Oger, Robert; Marlier, Catherine; Van De Vijver, Hans; Vandermeulen, Valerie; Van Huylenbroeck, Guido; Zamani, Sepideh; Curnel, Yannick; Mettepenningen, Evi

    2013-04-01

    The BELSPO funded project 'MERINOVA' deals with risks associated with extreme weather phenomena and with risks of biological origin such as pests and diseases. The major objectives of the proposed project are to characterise extreme meteorological events, assess the impact on Belgian agro-ecosystems, characterise their vulnerability and resilience to these events, and explore innovative adaptation options to agricultural risk management. The project comprises of five major parts that reflect the chain of risks: (i) Hazard: Assessing the likely frequency and magnitude of extreme meteorological events by means of probability density functions; (ii) Impact: Analysing the potential bio-physical and socio-economic impact of extreme weather events on agro-ecosystems in Belgium using process-based modelling techniques commensurate with the regional scale; (iii) Vulnerability: Identifying the most vulnerable agro-ecosystems using fuzzy multi-criteria and spatial analysis; (iv) Risk Management: Uncovering innovative risk management and adaptation options using actor-network theory and fuzzy cognitive mapping techniques; and, (v) Communication: Communicating to research, policy and practitioner communities using web-based techniques. The different tasks of the MERINOVA project require expertise in several scientific disciplines: meteorology, statistics, spatial database management, agronomy, bio-physical impact modelling, socio-economic modelling, actor-network theory, fuzzy cognitive mapping techniques. These expertises are shared by the four scientific partners who each lead one work package. The MERINOVA project will concentrate on promoting a robust and flexible framework by demonstrating its performance across Belgian agro-ecosystems, and by ensuring its relevance to policy makers and practitioners. Impacts developed from physically based models will not only provide information on the state of the damage at any given time, but also assist in understanding the links between different factors causing damage and determining bio-physical vulnerability. Socio-economic impacts will enlarge the basis for vulnerability mapping, risk management and adaptation options. A strong expert and end-user network will be established to help disseminating and exploiting project results to meet user needs.

  4. [Agro-ecosystem ammonia emission in Sichuan-Chongqing region].

    PubMed

    Li, Fu-chun; Han, Shen-hui; Yang, Jun; Zhang, Xu; Li, Ru-yan; Wei, Yuan-song; Fan, Mao-hong

    2009-10-15

    Ammonia (NH3) emission from agro-ecosystem in the Sichuan-Chongqing region during 1990-2004, was estimated by the regional nitrogen cycling model IAP-N. The county level agricultural activities data were used, and Sichuan-Chongqing region was divided into four sub-areas by the geographical characteristics , environment and local climatic conditions and administrative division. The results showed that average annual ammonia emissions (in nitrogen gauge) in 1990-1994, 1995-1999, 2000-2004 were 626.7, 670.5 and 698.8 Gg x a(-1) respectively. The ammonia emission appeared increasing trend, whereas, the contribution of various ammonia sources presented little change. For instance, in 2000-2004, the contributions of NH3 emission from fertilized cropland, manure management system and field residues burning to the total ammonia emission of agro-ecosystem in the Sichuan-Chongqing region were 53%, 46% and 1%, equals to 374.9, 318.2 and 5.6 Gg x a(-1) respectively. But the contributions were variable in different regions. Ammonia emission was primarily induced by fertilized cropland in Chengdu plain and Chongqing hilly area, whereas, in northwest sub-region of Sichuan province was manure management system. The geographical distribution of ammonia emission from agro-ecosystem in the Sichuan-Chongqing region was generally "east high and west low". Ammonia emissions in sub-regions of Chongqing hilly area, Chengdu plain, southwest and northwest sub-regions were 165.6, 408.8, 85.9 and 38.8 Gg x a(-1), respectively, during 2000-2004. At the same time, ammonia density were 20 and 28 kg x (hm2 x a)(-1) in sub-regions of the Chongqing hilly area and the Chengdu plain, whereas, 9.1 and 1.6 kg x (hm2 x a)(-1) in southwest and northwest sub-regions, respectively. The results will provide a scientific basis for making fertilizer effectively applied and mitigate NH3 and GHG emissions from agro-ecosystem of Sichuan-Chongqing region.

  5. The Resilience Assessment Framework: a common indicator for land management?

    NASA Astrophysics Data System (ADS)

    Cowie, Annette; Metternicht, Graciela; O'Connell, Deborah

    2015-04-01

    At the Rio+20 conference in June 2013, the United Nations Convention to Combat Desertification (UNCCD), the Convention on Biological Diversity (CBD), and the United Nations Framework Convention on Climate Change (UNFCCC) reinforced their mutual interests in building linkages between biodiversity conservation, sustainable land management, and climate change mitigation and adaptation. The UNCCD sees building resilience of agro-ecosystems as a common interest that could strengthen linkages between the conventions and deliver synergies in progressing goals of each of the conventions. Furthermore, enhancing resilience of productive agro-ecosystems is fundamental to food security and sustainable development, and thus aligns with the Sustainable Development Goals (SDGs). The Global Environment Facility (GEF) shares the interest of the conventions in building resilience in agro-ecosystems. Indicators of resilience are required for monitoring progress in these endeavors, application of a common indicator between the UNCCD, UNFCCC and CBD as a measure of both land-based adaptation and ecosystem resilience, could strengthen links between the conventions and increase attention to the broad benefits of improved land management. Consequently, the Scientific and Technical Advisory Panel (STAP) to the GEF commissioned the Commonwealth Scientific and Industrial Research Organisation (CSIRO) to produce a report reviewing the conceptual basis for resilience, and proposing an indicator approach that could meet the needs of the Conventions and the GEF for an indicator of agro-ecosystem resilience and land-based adaption. The paper presents a synthesis of scientific understanding of resilience in agro-ecosystems, reviews indicators that have been proposed, and, having concluded that none of the extant indicator approaches adequately assesses resilience of agro-ecosystems, proposes a new approach to the assessment of resilience. Recognizing that no single indicator of resilience is applicable to all agro-ecosystems, and that involvement of stakeholders is critical to discerning the critical variables to be assessed, the proposed framework uses an iterative participatory approach to characterise the system, considering also interactions across and within scales; identify the controlling variables, and assess proximity to thresholds, and adaptive capacity. The framework consists of four elements: Element A: System description; Element B Assessing the system; Element C Adaptive governance and management; Element D Participatory process. Element D is intended as a cross-cutting element, applying across Elements A to C, although Elements A and B can be applied as a desktop activity in a preliminary assessment. The results of the assessment are synthesised in "Resilience action indicators", that summarise the state of the system with respect to the need to adapt or transform. The presentation will summarise the framework and the responses of expert reviewers who identified strengths of the approach, and challenges for implementation, particularly at program and national scales. The presentation will emphasise the conceptual basis for the approach, and the role of scientists in testing, refining and operationalizing the approach.

  6. Hydrocentric view of Agro-ecosystem Resiliency to Extreme Hydrometeorological and Climate Events in the High Plains, US.

    NASA Astrophysics Data System (ADS)

    Munoz-Arriola, Francisco; Sharma, Ashutosh; Werner, Katherine; Chacon, Juan-Carlos; Corzo, Gerald; Goyal, Manish-Kumar

    2017-04-01

    An increasing incidence of Hydrometeorological and Climate Extreme Events (EHCEs) is challenging food, water, and ecosystem services security at local to global contexts. This study aims to understand how a large-scale representation of agroecosystems and ecosystems respond to EHCE in the Northern Highplains, US. To track such responses the Variable Infiltration Capacity model (VIC) Land Surface Hydrology model was used and two experiments were implemented. The first experiment uses the LAI MODIS15A2 product to capture dynamic responses of vegetation with a time span from 2000 to 2013. The second experiment used a climatological fixed seasonal cycle calculated as the average from the 2000-2013 dynamic MODIS15A2 product to isolate vegetation from soil physical responses. Based on the analyses of multiple hydrological variables and state variables and high-level organization of agroecosystems and ecosystems, we evidence how the influence of droughts and anomalously wet conditions affect hydrological resilience at large scale.

  7. [Pesticides in the tropical agricultural economy systems: Evaluation of present knowledge of the problem].

    PubMed

    García, A R

    1976-06-01

    Man is an integral part of the ecosystem and any action of his against the environment has an effect against man himself. An Agro-ecosystem is a unit composed of the total complex of organisms in an area under cultivation, plus the totality of the physical environmental conditions and the modifications introduced by man, who manages the agro-ecosystem for his own benefit. The use of pesticides has been necessary for the agricultural development of some tropical areas. Unfortunately, the inadequate use of this input has caused many problems for himself. These include destruction of natural resources; intoxications; pesticide residues in water and foods; secondary pest outbreaks; increase in illnesses transmitted by certain arthropods; loss of foreign exchange; unemployment; malnutrition; disability; high infant mortality and poverty. A better use of agro-ecosystem management techniques can lead to a rational sustained utilization of land resources. Chemical pesticides can be considered as one of the factors in pest management, and not necessarily the only one available.

  8. Impact of Seasonal Variability in Water, Plant and Soil Nutrient Dynamics in Agroecosystems

    NASA Astrophysics Data System (ADS)

    Pelak, N. F., III; Revelli, R.; Porporato, A. M.

    2017-12-01

    Agroecosystems cover a significant fraction of the Earth's surface, making their water and nutrient cycles a major component of global cycles across spatial and temporal scales. Most agroecosystems experience seasonality via variations in precipitation, temperature, and radiation, in addition to human activities which also occur seasonally, such as fertilization, irrigation, and harvesting. These seasonal drivers interact with the system in complex ways which are often poorly characterized. Crop models, which are widely used for research, decision support, and prediction of crop yields, are among the best tools available to analyze these systems. Though normally constructed as a set of dynamical equations forced by hydroclimatic variability, they are not often analyzed using dynamical systems theory and methods from stochastic ecohydrology. With the goal of developing this viewpoint and thus elucidating the roles of key feedbacks and forcings on system stability and on optimal fertilization and irrigation strategies, we develop a minimal dynamical system which contains the key components of a crop model, coupled to a carbon and nitrogen cycling model, driven by seasonal fluctuations in water and nutrient availability, temperature, and radiation. External drivers include seasonally varying climatic conditions and random rainfall forcing, irrigation and fertilization as well as harvesting. The model is used to analyze the magnitudes and interactions of the effects of seasonality on carbon and nutrient cycles, crop productivity, nutrient export of agroecosystems, and optimal management strategies with reference to productivity, sustainability and profitability. The impact of likely future climate scenarios on these systems is also discussed.

  9. Development of a composite soil degradation assessment index for cocoa agroecosystems in southwestern Nigeria

    NASA Astrophysics Data System (ADS)

    Adenrele Adeniyi, Sunday; de Clercq, Willem Petrus; van Niekerk, Adriaan

    2017-08-01

    Cocoa agroecosystems are a major land-use type in the tropical rainforest belt of West Africa, reportedly associated with several ecological changes, including soil degradation. This study aims to develop a composite soil degradation assessment index (CSDI) for determining the degradation level of cocoa soils under smallholder agroecosystems of southwestern Nigeria. Plots where natural forests have been converted to cocoa agroecosystems of ages 1-10, 11-40, and 41-80 years, respectively representing young cocoa plantations (YCPs), mature cocoa plantations (MCPs), and senescent cocoa plantations (SCPs), were identified to represent the biological cycle of the cocoa tree. Soil samples were collected at a depth of 0 to 20 cm in each plot and analysed in terms of their physical, chemical, and biological properties. Factor analysis of soil data revealed four major interacting soil degradation processes: decline in soil nutrients, loss of soil organic matter, increase in soil acidity, and the breakdown of soil textural characteristics over time. These processes were represented by eight soil properties (extractable zinc, silt, soil organic matter (SOM), cation exchange capacity (CEC), available phosphorus, total porosity, pH, and clay content). These soil properties were subjected to forward stepwise discriminant analysis (STEPDA), and the result showed that four soil properties (extractable zinc, cation exchange capacity, SOM, and clay content) are the most useful in separating the studied soils into YCP, MCP, and SCP. In this way, we have sufficiently eliminated redundancy in the final selection of soil degradation indicators. Based on these four soil parameters, a CSDI was developed and used to classify selected cocoa soils into three different classes of degradation. The results revealed that 65 % of the selected cocoa farms are moderately degraded, while 18 % have a high degradation status. The numerical value of the CSDI as an objective index of soil degradation under cocoa agroecosystems was statistically validated. The results of this study reveal that soil management should promote activities that help to increase organic matter and reduce Zn deficiency over the cocoa growth cycle. Finally, the newly developed CSDI can provide an early warning of soil degradation processes and help farmers and extension officers to implement rehabilitation practices on degraded cocoa soils.

  10. Vulnerability and Risk of Agro-ecosystems Facing Increased Salinity Intrusion in the Mekong Delta, Viet Nam

    NASA Astrophysics Data System (ADS)

    Renaud, F.; Sebesvari, Z.; Nguyen, M. T.; Hagenlocher, M.

    2016-12-01

    The Vietnamese portion of the Mekong Delta increasingly suffers from salinity intrusion in its freshwater system, as exemplified by the historically high salinity levels recorded during the 2016 dry season. Although this exceptional situation was linked to the El Niño phenomena, many factors contribute to an increasing salinization of coastal areas. Salinity intrusion is a natural process in this tidal area but its extent is increasing and projected to worsen due to increased demand for water, diversion/storage of water flows in the Mekong river and its tributaries, land subsidence linked to groundwater over-abstraction, changes in land use and water management in coastal areas, and sea level rise. The Mekong Delta remains predominantly an agricultural landscape which contributes the majority of the rice, aquaculture, and fruit production of the country. These systems will need to be adapted to increased salinity levels. We will present results from two research projects, DeltAdapt and DELTAS, which were designed to allow understanding of, respectively (1) the main drivers of change of agro-ecosystems in coastal areas of the delta and (2) the relative vulnerabilities and risks deltaic social-ecological systems face with respect to various environmental hazards. We used the Global Delta Vulnerability Index developed within the DELTAS project to characterize the vulnerabilities and risks faced by coastal provinces of the delta with respect to salinity intrusion. The analysis allows us to understand which social, economic, and ecological variables index explain the relative vulnerability of the provinces. In addition, drivers of change (e.g. policy, economic, social, environmental) of coastal agro-ecosystems were systematically analyzed through 80 interviews and 7 focus group discussions in the provinces of Kien Giang and Soc Trang within the DeltAdapt project. This was combined with the analysis of Vietnamese policies to determine which are the important drivers of change in the region and how these contribute (or not) to the adaptation of agro-ecosystems facing increased salinity intrusion. By combining these results, we will point to potential policies that could be considered by various authorities to allow for a greater adaptability of agro-ecosystems in the coastal provinces of the region.

  11. Relationships between soil organic matter pools and nitrous oxide emissions of agroecosystems in the Brazilian Cerrado.

    PubMed

    de Figueiredo, Cícero Célio; de Oliveira, Alexsandra Duarte; Dos Santos, Isis Lima; Ferreira, Eloisa Aparecida Belleza; Malaquias, Juaci Vitoria; de Sá, Marcos Aurélio Carolino; de Carvalho, Arminda Moreira; Dos Santos, João de Deus Gomes

    2018-03-15

    In the Brazilian Cerrado, despite the increasing adoption of no-till systems, there are still extended areas under conventional soil management systems that reduce soil carbon (C) and nitrogen (N) stocks and increase the emissions of greenhouse gases, such as nitrous oxide (N 2 O). Conservation agroecosystems, such as no-till, have been proposed as a strategy to mitigate agriculture-induced climatic changes through reductions in N 2 O emissions. However, the relationship between organic matter and N 2 O emissions from soils under different agroecosystems is not yet clear. This study hypothesized that agroecosystems under no-till promote an accumulation of labile and stable SOM fractions along with a reduction of N 2 O emissions. This study evaluated the effects of crop-rotation agroecosystems: i) on C and N pools and labile and stable SOM fractions; ii) on cumulative N 2 O emissions; and iii) on the relationships between SOM fractions and N 2 O emissions. The agricultural systems consisted of: (I) soybean followed by sorghum under no-tillage (NT1); (II) maize followed by pigeon pea under no-tillage (NT2); (III) soybean under conventional tillage followed by fallow soil (CT); (IV) and native Cerrado (CER). After CT for 18years, following the replacement of CER, the soil C stock in the 0-20cm layer was reduced by 0.64tha -1 year -1 . The no-till systems were more efficient in accumulating labile and stable C fractions with values close to those observed under CER, and were directly related to lower soil N 2 O emissions. The cumulative pattern of N 2 O emissions was inverse to that of the following SOM fractions: microbial biomass carbon, permanganate-oxidizable carbon, particulate organic carbon, inert carbon, and humic substances. Based on principal component analysis, the CT was generally separated from the other land use systems. This separation was strongly influenced by the low C contents in the different SOM fractions and higher N 2 O emissions promoted by the CT. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Participatory data collection and monitoring of agricultural pest dynamics for climate-resilient coffee production using Tiko'n, a generic tool to develop agroecological food web models

    NASA Astrophysics Data System (ADS)

    Rojas, M.; Malard, J. J.; Adamowski, J. F.; Tuy, H.

    2016-12-01

    Climate variability impacts agricultural processes through many mechanisms. For example, the proliferation of pests and diseases increases with warmer climate and alternated wind patterns, as longer growing seasons allow pest species to complete more reproductive cycles and changes in the weather patterns alter the stages and rates of development of pests and pathogens. Several studies suggest that enhancing plant diversity and complexity in farming systems, such as in agroforestry systems, reduces the vulnerability of farms to extreme climatic events. On the other hand, other authors have argued that vegetation diversity does not necessarily reduce the incidence of pests and diseases, highlighting the importance of understanding how, where and when it is recommendable to diversify vegetation to improve pest and disease control, and emphasising the need for tools to develop, monitor and evaluate agroecosystems. In order to understand how biodiversity can enhance ecosystem services provided by the agroecosystem in the context of climatic variability, it is important to develop comprehensive models that include the role of trophic chains in the regulation of pests, which can be achieved by integrating crop models with pest-predator models, also known as agroecosystem network (AEN) models. Here we present a methodology for the participatory data collection and monitoring necessary for running Tiko'n, an AEN model that can also be coupled to a crop model such as DSSAT. This methodology aims to combine the local and practical knowledge of farmers with the scientific knowledge of entomologists and agronomists, allowing for the simplification of complex ecological networks of plant and insect interactions. This also increases the acceptability, credibility, and comprehension of the model by farmers, allowing them to understand their relationship with the local agroecosystem and their potential to use key agroecosystem principles such as functional diversity to mitigate climate variability impacts. Preliminary results of a study currently being conducted in a coffee agroforestry system in El Quebracho, Guatemala, will be presented, where the data was directly collected by farmers during eight consecutive months. Finally, future recommendations from lessons learnt during this study will be discussed.

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

    PubMed

    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

  14. Meteorological risks as drivers of innovation for agroecosystem management

    NASA Astrophysics Data System (ADS)

    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 season. A methodology for identifying agro-ecosystem vulnerability was developed using spatially explicit information and was tested for arable crop production in Belgium. The different components of vulnerability for a region include spatial information on meteorology, soil available water content, soil erosion, the degree of waterlogging, crop share and the diversity of potato varieties. 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. Risk types are further distinguished according to production, market, institutional, financial and liability risks. Strategies are often combined in the risk management strategy of a farmer and include reduction and prevention, mitigation, coping and impact reduction. Based on an extensive literature review, a portfolio of potential strategies was identified at farm, market and policy level. Research hypotheses were tested using an on-line questionnaire on knowledge of agricultural risk, measuring the general risk aversion of the farmer and risk management strategies. The "chain of risk" approach adopted as a research methodology allows for investigating the hypothesis that meteorological risks act as drivers for agricultural innovation. Risks related to extreme weather events in Belgium are mainly caused by heat, frost, excess rainfall, drought and storms, and their impact is predominantly felt by arable, horticultural and extensive dairy farmers. Quantification of the risk is evaluated in terms of probability of occurrence, magnitude, frequency and extent of impact on several agro-ecosystems services. The spatial extent of vulnerability is developed by integrating different layers of geo-information, while risk management is analysed using questionnaires and economic modelling methods. Future work will concentrate on the further development and testing of the currently developed modelling methodologies. https://merinova.vito.be The research is funded by the Belgian Science Policy Organisation (Belspo) under contract nr SD/RI/03A.

  15. How Does Recycling of Livestock Manure in Agroecosystems Affect Crop Productivity, Reactive Nitrogen Losses, and Soil Carbon Balance?

    PubMed

    Xia, Longlong; Lam, Shu Kee; Yan, Xiaoyuan; Chen, Deli

    2017-07-05

    Recycling of livestock manure in agroecosystems to partially substitute synthetic fertilizer nitrogen (N) input is recommended to alleviate the environmental degradation associated with synthetic N fertilization, which may also affect food security and soil greenhouse gas (GHG) emissions. However, how substituting livestock manure for synthetic N fertilizer affects crop productivity (crop yield; crop N uptake; N use efficiency), reactive N (Nr) losses (ammonia (NH 3 ) emission, N leaching and runoff), GHG (methane, CH 4 ; and nitrous oxide, N 2 O; carbon dioxide) emissions and soil organic carbon (SOC) sequestration in agroecosystems is not well understood. We conducted a global meta-analysis of 141 studies and found that substituting livestock manure for synthetic N fertilizer (with equivalent N rate) significantly increased crop yield by 4.4% and significantly decreased Nr losses via NH 3 emission by 26.8%, N leaching by 28.9% and N runoff by 26.2%. Moreover, annual SOC sequestration was significantly increased by 699.6 and 401.4 kg C ha -1 yr -1 in upland and paddy fields, respectively; CH 4 emission from paddy field was significantly increased by 41.2%, but no significant change of that was observed from upland field; N 2 O emission was not significantly affected by manure substitution in upland or paddy fields. In terms of net soil carbon balance, substituting manure for fertilizer increased carbon sink in upland field, but increased carbon source in paddy field. These results suggest that recycling of livestock manure in agroecosystems improves crop productivity, reduces Nr pollution and increases SOC storage. To attenuate the enhanced carbon source in paddy field, appropriate livestock manure management practices should be adopted.

  16. No correlation between the diversity and productivity of assemblages: evidence from the phytophage and predator assemblages in various cotton agroecosystems.

    PubMed

    Gao, Feng; Men, XingYuan; Ge, Feng

    2014-09-01

    Biodiversity research has shown that primary productivity increases with plant species number, especially in many experimental grassland systems. Here, we assessed the correlation between productivity and diversity of phytophages and natural enemy assemblages associated with planting date and intercropping in four cotton agroecosystems. Twenty-one pairs of data were used to determine Pearson correlations between species richness, total number of individuals, diversity indices and productivity for each assemblage every five days from 5 June to 15 September 2012. At the same trophic level, the productivity exhibited a significant positive correlation with species richness of the phytophage or predator assemblage. A significant correlation was found between productivity and total number of individuals in most cotton fields. However, no significant correlations were observed between productivity and diversity indices (including indices of energy flow diversity and numerical diversity) in most cotton fields for either the phytophage or the predator assemblages. Species richness of phytophage assemblage and total individual numbers were significantly correlated with primary productivity. Also, species richness of natural enemy assemblage and total number of individuals correlated with phytophage assemblage productivity. A negative but not significant correlation occurred between the indices of numerical diversity and energy flow diversity and lower trophic-level productivity in the cotton-phytophage and phytophage-predator assemblages for most intercropped cotton agroecosystems. Our results clearly showed that there were no correlations between diversity indices and productivity within the same or lower trophic levels within the phytophage and predator assemblages in cotton agroecosystems, and inter-cropped cotton fields had a stronger ability to support the natural enemy assemblage and potentially to reduce phytophages.

  17. Action versus Result-Oriented Schemes in a Grassland Agroecosystem: A Dynamic Modelling Approach

    PubMed Central

    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. PMID:22496746

  18. Ground beetles in Mediterranean olive agroecosystems: Their significance and functional role as bioindicators (Coleoptera, Carabidae)

    PubMed Central

    Mazzei, Antonio; Bonacci, Teresa; Scalercio, Stefano; Iannotta, Nino; Brandmayr, Pietro

    2018-01-01

    The impact of agricultural practices and soil management on the communities of arthropods living in the agricultural landscape is acknowledged as a critical issue by the literature, and it needs to be better investigated to improve the ecological sustainability of agriculture. In the present study, we aimed to study how soil management affect carabid species distribution in one of the most typical agroecosystem of the Mediterranean region, i.e. the olive grove. In South Italy olive plantations feature different types of soil management, from tillage to half- or full-cover cropping. Species distribution has been examined for a total of 10,189 individuals and 62 species collected from 17 sites. Notably from our analysis we have observed that three factors (climax vegetation, soil features and soil management) explained half of the data variability. The composition of species groupings mirrors both bioclimatic conditions (climax vegetation) and soil features, especially watering, while soil management affects the species distribution, with different intensity from site to site. Eleven species have been recognized as the most abundant in the different facets of the studied olive groves and consequently designated as characteristics of the olive agroecosystem. The species traits of the sampled species have been weighted for a compelling evaluation of the effects of agricultural management on biodiversity, showing uniform traits distribution when coping with the ecological factors that characterize the different plantation facets. We have found that carabid beetles can be used as model organisms for studying the effects of agricultural practices. Our study suggests that the interaction of man-induced trasformation with the natural background of the olive agroecosystem may be difficult to disentangle, so that such complexity must be taken into account when carabid beetles are expected to provide an ecosystem service for good agricultural practices. PMID:29558493

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

    PubMed Central

    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. PMID:25036276

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

    PubMed

    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.

  1. Spider assemblages associated with different crop stages of irrigated rice agroecosystems from eastern Uruguay

    PubMed Central

    Ginella, Juaquín; Cadenazzi, Mónica; Castiglioni, Enrique A.; Martínez, Sebastián; Casales, Luis; Caraballo, María P.; Laborda, Álvaro; Simo, Miguel

    2018-01-01

    Abstract The rice crop and associated ecosystems constitute a rich mosaic of habitats that preserve a rich biological diversity. Spiders are an abundant and successful group of natural predators that are considered efficient in the biocontrol of the major insect pests in agroecosystems. Spider diversity in different stages of the rice crop growth from eastern Uruguay was analysed. Field study was developed on six rice farms with rotation system with pasture, installed during intercropping stage as cover crop. Six rice crops distributed in three locations were sampled with pitfall and entomological vaccum suction machine. Sixteen families, representing six guilds, were collected. Lycosidae, Linyphiidae, Anyphaenidae and Tetragnathidae were the most abundant families (26%, 25%, 20% and 12%, respectively) and comprised more than 80% of total abundance. Other hunters (29%), sheet web weavers (25%) and ground hunters (24%) were the most abundant guilds. Species composition along different crop stages was significantly different according to the ANOSIM test. The results showed higher spider abundance and diversity along the crop and intercrop stages. This study represents the first contribution to the knowledge of spider diversity associated with rice agroecosystem in the country. PMID:29755261

  2. Spider assemblages associated with different crop stages of irrigated rice agroecosystems from eastern Uruguay.

    PubMed

    Bao, Leticia; Ginella, Juaquín; Cadenazzi, Mónica; Castiglioni, Enrique A; Martínez, Sebastián; Casales, Luis; Caraballo, María P; Laborda, Álvaro; Simo, Miguel

    2018-01-01

    The rice crop and associated ecosystems constitute a rich mosaic of habitats that preserve a rich biological diversity. Spiders are an abundant and successful group of natural predators that are considered efficient in the biocontrol of the major insect pests in agroecosystems. Spider diversity in different stages of the rice crop growth from eastern Uruguay was analysed. Field study was developed on six rice farms with rotation system with pasture, installed during intercropping stage as cover crop. Six rice crops distributed in three locations were sampled with pitfall and entomological vaccum suction machine. Sixteen families, representing six guilds, were collected. Lycosidae, Linyphiidae, Anyphaenidae and Tetragnathidae were the most abundant families (26%, 25%, 20% and 12%, respectively) and comprised more than 80% of total abundance. Other hunters (29%), sheet web weavers (25%) and ground hunters (24%) were the most abundant guilds. Species composition along different crop stages was significantly different according to the ANOSIM test. The results showed higher spider abundance and diversity along the crop and intercrop stages. This study represents the first contribution to the knowledge of spider diversity associated with rice agroecosystem in the country.

  3. Carbon flow analysis of China's agro-ecosystem from 1980 to 2013: A perspective from substance flow analysis.

    PubMed

    Liu, Yu; Wang, Can; Chen, Minpeng

    2017-05-01

    Research on carbon cycling has attracted attention from both scientists and policy-makers. Based on material flow analysis, this study systematically budgets the carbon inputs, outputs and balance from 1980 to 2013 for China's agro-ecosystem and its sub-systems, including agricultural land use, livestock breeding and rural life. The results show that from 1980 to 2013, both the carbon input and output were growing gradually, with the carbon input doubling from 1.6PgC/year in 1980 to 3.4PgC/year in 2013, while carbon output grew from 2.2PgC/year in 1980 to 3.8PgC/year in 2013. From 1980 to 2013, the crop production system in China has remained a carbon source, and the agricultural land uses were also almost all carbon sources instead of carbon sinks. As soil carbon stock plays a very important role in deciding the function of China's agro-ecosystem as a carbon sink or source, practices that can promote carbon storage and sequestration will be an essential component of low carbon agriculture development in China. Copyright © 2016. Published by Elsevier B.V.

  4. Managing Nitrogen in Croplands: Implications for Increasing Ecosystem Services in Agricultural Landscapes

    NASA Astrophysics Data System (ADS)

    Jackson, L.

    2011-12-01

    Many agricultural landscapes in the temperate zone are dominated by agroecosystems that are managed with high inputs of agrochemicals, including synthetic nitrogen (N) fertilizers. The process of agricultural intensification increases crop production per unit area, but also often results in loss of environmental quality (such as N contamination of waters, eutrophication, atmospheric N deposition, and emissions of nitrous oxide (N2O), a potent greenhouse gas). Loss of biodiversity and its 'functional homogenization' is another concern. Not only does little land in these landscapes remain in natural ecosystems, but there are negative off-site impacts of intensive agriculture on non-target organisms. Segregating agroecosystems with high-input agricultural production from natural ecosystems (land sparing) is one view to support both food security and biodiversity conservation. But proponents of land sparing rarely address the loss of other ecosystem services, such as those related to environmental quality, health, and human well-being (e.g., livelihoods and cultural values). An emerging view is that increased reliance on ecological processes in agroecosystems ('ecological intensification') is more feasible when the landscape mosaic includes planned and unplanned biodiversity. This requires research on how to support multiple ecosystem services through the integration of agricultural production and biodiversity conservation in the same landscape, and how ecological and physico-chemical processes at various spatial scales are interlinked. It is an enormous challenge to increase reliance on ecological processes for N availability for crop productivity. There are skeptics who think that this will be detrimental for food security, despite benefits for other types of ecosystem services. Using examples from agricultural landscapes in California, mechanisms for ecologically-based N cycling will be discussed, such as: 1) increasing the reservoir of soil organic N and the dynamic turnover and supply of N via soil microbial N transformations and root symbioses; 2) developing farming systems that rely on crop rotations and functional groups that increase N supply and retention; 3) minimizing N losses through better understanding of agroecosystem biogeochemistry; and 4) overcoming the problems associated with open N cycles in agroecosystems with landscape features such buffer strips, managed riparian corridors, and patchy land use types. The capacity to compensate for high non-renewable inputs in specific farming situations will be addressed, along with factors that increase the capacity for different types of farmers to adopt N management practices that enhance the provision of multiple types of ecosystem services.

  5. A semiarid fruit agroecosystem as a conservation-friendly option for small mammals in an anthropized landscape in Mexico.

    PubMed

    Riojas-López, Mónica E; Mellink, Eric; Luévano, Jaime

    2018-03-01

    Many studies have addressed the potential of low-input agroecosystems for biological conservation. However, most have been carried out on annual agroecosystems in temperate, developed countries. As agricultural surface will increase and natural protected areas alone will not warrant the conservation of biodiversity, it is crucial to include different types of agroecosystems in research and conservation efforts. In Mexico, perennial, low-input, fruit-oriented nopal orchards (Opuntia spp.), one of the few crops suitable for semiarid areas, are the 10th out of 61 most important fruit crops grown in the country. We assessed their value for conservation in an anthropized landscape by comparing their rodent assemblages with those in adjacent habitats and determined the influence of the latter on the rodent communities inside them. We live-trapped rodents in 12 orchards and adjacent natural xeric shrubland, grassland, and cropland. We captured 19 different species, of which 17 used the orchards. Four are Mexican endemics. Orchards have higher α diversity, species richness, and abundance than cropland and grassland and are not different from shrubland. The dominant rodent species are the same in orchards and shrubland, and where these two meet they integrate into one habitat. Within-habitat quality is a critical driver of the composition and diversity of rodent communities in the orchards studied, and the neighboring habitats do not modify them substantially. Increasing within-patch heterogeneity beyond a certain level is at the expense of habitat integrity and produces small-scale fragmentation reducing habitat quality. At a landscape scale, orchards contribute importantly to regional rodent diversity compared with other land use types, and appear to increase habitat connectivity between patches of shrubland. Orchards' higher α diversity would give them higher ecological resilience and make them better suited than grassland and cropland to contribute to the conservation of local biota. Nopal orchards should be considered conservation allies and incorporated in regional conservation plans. Regrettably, their future is unwarranted as producers face low revenues and lack of governmental support. Our confirmation that orchards have an important, positive impact on biodiversity can be used as a strong argument to lobby for incentives to safeguard this environmental friendly, low-input agroecosystem. © 2017 by the Ecological Society of America.

  6. Interaction complexity matters: disentangling services and disservices of ant communities driving yield in tropical agroecosystems

    PubMed Central

    Wielgoss, Arno; Tscharntke, Teja; Rumede, Alfianus; Fiala, Brigitte; Seidel, Hannes; Shahabuddin, Saleh; Clough, Yann

    2014-01-01

    Owing to complex direct and indirect effects, impacts of higher trophic levels on plants is poorly understood. In tropical agroecosystems, ants interact with crop mutualists and antagonists, but little is known about how this integrates into the final ecosystem service, crop yield. We combined ant exclusion and introduction of invasive and native-dominant species in cacao agroecosystems to test whether (i) ant exclusion reduces yield, (ii) dominant species maximize certain intermediate ecosystem services (e.g. control of specific pests) rather than yield, which depends on several, cascading intermediate services and (iii) even, species-rich ant communities result in highest yields. Ants provided services, including reduced leaf herbivory and fruit pest damage and indirect pollination facilitation, but also disservices, such as increased mealybug density, phytopathogen dissemination and indirect pest damage enhancement. Yields were highest with unmanipulated, species-rich, even communities, whereas ant exclusion decreased yield by 27%. Introduction of an invasive-dominant ant decreased species density and evenness and resulted in 34% lower yields, whereas introduction of a non-invasive-dominant species resulted in similar species density and yields as in the unmanipulated control. Species traits and ant community structure affect services and disservices for agriculture in surprisingly complex ways, with species-rich and even communities promoting highest yield. PMID:24307667

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

    PubMed

    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.

  8. Predator- and Scavenger-Mediated Ecosystem Services Determined by Distance to Field-Forest Interface in the Maine Lowbush Blueberry Agroecosystem.

    PubMed

    Jones, Matthew S; Halteman, William A; Drummond, Francis A

    2016-10-01

    Predators and scavengers play a vital role in regulating insect pests, weeds, and vertebrate scat in perennial agroecosystems. Understanding how farm management practices and surrounding habitat influence these beneficial ecosystem services contributes to our understanding of these complex ecological systems and guides future management decisions. In a mensurative 2-yr study, we determined how different pest management strategies and surrounding forest composition influenced levels of sentinel insect pupae, weed seeds, and deer scat (feces) removal. Removal of these bioresources was measured within 12 commercial lowbush blueberry fields during 2011 and 2012; farms differed in surrounding landscape composition and farm management strategies. Both the removal of sentinel pupae and scat, was significantly higher within field interiors than at field edges and within adjacent forests. Additionally, farm management strategy interacted with field position to result in significantly higher scat removal in conventional field interiors than organic field interiors. Surrounding forest composition had variable effects on removal of materials. Our results indicate higher levels of activity within field centers as opposed to field edges; this is contrary to what has been observed in other perennial cropping agroecosystems. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Spatio-temporal trends in crop damage inform recent climate-mediated expansion of a large boreal herbivore into an agro-ecosystem.

    PubMed

    Laforge, Michel P; Michel, Nicole L; Brook, Ryan K

    2017-11-09

    Large-scale climatic fluctuations have caused species range shifts. Moose (Alces alces) have expanded their range southward into agricultural areas previously not considered moose habitat. We found that moose expansion into agro-ecosystems is mediated by broad-scale climatic factors and access to high-quality forage (i.e., crops). We used crop damage records to quantify moose presence across the Canadian Prairies. We regressed latitude of crop damage against North Atlantic Oscillation (NAO) and crop area to test the hypotheses that NAO-mediated wetland recharge and occurrence of more nutritious crop types would result in more frequent occurrences of crop damage by moose at southerly latitudes. We examined local-scale land use by generating a habitat selection model to test our hypothesis that moose selected for areas of high crop cover in agro-ecosystems. We found that crop damage by moose occurred farther south during dry winters and in years with greater coverage of oilseeds. The results of our analyses support our hypothesis that moose movement into cropland is mediated by high-protein crops, but not by thermoregulatory habitat at the scale examined. We conclude that broad-scale climate combined with changing land-use regimes are causal factors in species' range shifts and are important considerations when studying changing animal distributions.

  10. The ecological role of ants in two Mexican agroecosystems.

    PubMed

    Risch, Stephen J; Carroll, C Ronald

    1982-10-01

    The development of the ant communities and their foraging dynamics were studied in two annual agroecosystems of the Mexican tropical lowlands: a "forest milpa" of corn, beans, and squash made by cutting and buring 40-year-old forest, and a "field milpa" of corn, beans, and squash made by plowing 1-year-old second growth. The ant community was sampled using tuna fish baits 26, 52, 110 and 353 days after planting. Although immediately after planting the same number of ant species occurred in each milpa type, thereafter the ant faunas diverged. The field milpa became completely dominated by the native fire ant, Solenopsis geminata, while the number of ant species in the forest milpa gradually increased over time, reaching eight species 110 days after planting and 14 species by 353 days. Initially S. geminata dominated the ant fauna in the forest milpa (occurring on 90% of the baits), but by 353 days planting it was found on only 26% of the occupied baits. Ant foraging efficiency, as measured by proportion of tuna baits occupied and the removal rates of dead Drosophila fly baits, was much higher (by a factor of 2 to 3) in the field than the forest milpa. This was caused by the extremely high density of S. geminata colonies in the field milpa. The simple Solenopsis-dominated community of the field milpa may be much more effective in biological control than the more diverse community of the forest milpa. Although S. geminata has potential negative impacts in annual agroecosystems (it stings, eats corn seeds, and guards homopterams), its overall impact appears to be beneficial. As forested areas of the lowland wet tropics are increasingly cut and converted to annual agriculture, the primary ant inhabitant of these highly disturbed environments, S. geminata, will necessarily play a much more significant ecological role in agroecosystems.

  11. Combined effects of climate and land-use change on the provision of ecosystem services in rice agro-ecosystems

    NASA Astrophysics Data System (ADS)

    Langerwisch, Fanny; Václavík, Tomáš; von Bloh, Werner; Vetter, Tobias; Thonicke, Kirsten

    2018-01-01

    Irrigated rice croplands are among the world’s most important agro-ecosystems. They provide food for more than 3.5 billion people and a range of other ecosystem services (ESS). However, the sustainability of rice agro-ecosystems is threatened by continuing climate and land-use changes. To estimate their combined effects on a bundle of ESS, we applied the vegetation and hydrology model LPJmL to seven study areas in the Philippines and Vietnam. We quantified future changes in the provision of four essential ESS (carbon storage, carbon sequestration, provision of irrigation water and rice production) under two climate scenarios (until 2100) and three site-specific land-use scenarios (until 2030), and examined the synergies and trade-offs in ESS responses to these drivers. Our results show that not all services can be provided in the same amounts in the future. In the Philippines and Vietnam the projections estimated a decrease in rice yields (by approximately 30%) and in carbon storage (by 15%) and sequestration (by 12%) towards the end of the century under the current land-use pattern. In contrast, the amount of available irrigation water was projected to increase in all scenarios by 10%-20%. However, the results also indicate that land-use change may partially offset the negative climate impacts in regions where cropland expansion is possible, although only at the expense of natural vegetation. When analysing the interactions between ESS, we found consistent synergies between rice production and carbon storage and trade-offs between carbon storage and provision of irrigation water under most scenarios. Our results show that not only the effects of climate and land-use change alone but also the interaction between ESS have to be considered to allow sustainable management of rice agro-ecosystems under global change.

  12. Large-scale Agroecosytem's Resiliency to Extreme Hydrometeorological and Climate Extreme Events in the Missouri River Basin

    NASA Astrophysics Data System (ADS)

    Munoz-Arriola, F.; Smith, K.; Corzo, G.; Chacon, J.; Carrillo-Cruz, C.

    2015-12-01

    A major challenge for water, energy and food security relies on the capability of agroecosyststems and ecosystems to adapt to a changing climate and land use changes. The interdependency of these forcings, understood through our ability to monitor and model processes across scales, indicate the "depth" of their impact on agroecosystems and ecosystems, and consequently our ability to predict the system's ability to return to a "normal" state. We are particularly interested in explore two questions: (1) how hydrometeorological and climate extreme events (HCEs) affect sub-seasonal to interannual changes in evapotranspiration and soil moisture? And (2) how agroecosystems recover from the effect of such events. To address those questions we use the land surface hydrologic Variable Infiltration Capacity (VIC) model and the Moderate Resolution Imaging Spectrometer-Leaf Area Index (MODIS-LAI) over two time spans (1950-2013 using a seasonal fixed LAI cycle) and 2001-2013 (an 8-day MODIS-LAI). VIC is forced by daily/16th degree resolution precipitation, minimum and maximum temperature, and wind speed. In this large-scale experiment, resiliency is defined by the capacity of a particular agroecosystem, represented by a grid cell's ET, SM, and LAI to return to a historical average. This broad, yet simplistic definition will contribute to identify the possible components and their scales involved in agroecosystems and ecosystems capacity to adapt to the incidence of HCEs and technologies used to intensify agriculture and diversify their use for food and energy production. Preliminary results show that dynamical changes in land use, tracked by MODIS data, require larger time spans to address properly the influence of technologic improvements in crop production as well as the competition for land for biofuel vs. food production. On the other hand, fixed seasonal changes in land use allow us just to identify hydrologic changes mainly due to climate variability.

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

    PubMed

    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 targets but also fruit quality to meet requirements for guava processing.

  14. Guava Waste to Sustain Guava (Psidium guajava) Agroecosystem: Nutrient “Balance” Concepts

    PubMed Central

    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 targets but also fruit quality to meet requirements for guava processing. PMID:27621735

  15. Multi-Season Regional Analysis of Multi-Species Occupancy: Implications for Bird Conservation in Agricultural Lands in East-Central Argentina

    PubMed Central

    Goijman, Andrea Paula; Conroy, Michael. J.; Bernardos, Jaime Nicolás; Zaccagnini, María Elena

    2015-01-01

    Rapid expansion and intensification of agriculture create challenges for the conservation of biodiversity and associated ecosystem services. In Argentina, the total row crop planted area has increased in recent decades with the expansion of soybean cultivation, homogenizing the landscape. In 2003 we started the first long-term, large-scale bird monitoring program in agroecosystems of central Argentina, in portions of the Pampas and Espinal ecoregions. Using data from this program, we evaluated the effect of land use and cover extent on birds between 2003-2012, accounting for imperfect detection probabilities using a Bayesian hierarchical, multi-species and multi-season occupancy model. We tested predictions that species diversity is positively related to habitat heterogeneity, which in intensified agroecosystems is thought to be mediated by food availability; thus the extent of land use and cover is predicted to affect foraging guilds differently. We also infer about ecosystem services provisioning and inform management recommendations for conservation of birds. Overall our results support the predictions. Although many species within each guild responded differently to land use and native forest cover, we identified generalities for most trophic guilds. For example, granivorous gleaners, ground insectivores and omnivores responded negatively to high proportions of soybean, while insectivore gleaners and aerial foragers seemed more tolerant. Habitat heterogeneity would likely benefit most species in an intensified agroecosystem, and can be achieved with a diversity of crops, pastures, and natural areas within the landscape. Although most studied species are insectivores, potentially beneficial for pest control, some guilds such as ground insectivores are poorly represented, suggesting that agricultural intensification reduces ecological functions, which may be recovered through management. Continuation of the bird monitoring program will allow us to continue to inform for conservation of birds in agroecosystems, identify research needed to reduce key uncertainties, and anticipate the effects of changes in agriculture in central Argentina. PMID:26086250

  16. Biological and genetic features of introduced aphid populations in agroecosystems.

    PubMed

    Figueroa, Christian C; Fuentes-Contreras, Eduardo; Molina-Montenegro, Marco A; Ramírez, Claudio C

    2018-04-01

    In agroecosystems, introduced aphids that reproduce by obligate parthenogenesis (OP) show strong biased representation of a few genotypes (superclones), whereas species with cyclical parthenogenesis (CP) exhibit the opposite trend with many unique genotypes. We analyzed the biological and genetic features of 23 different aphid species introduced in different geographic areas and climates, finding putative superclones in about 60% of them. We have examined the proximal causes for aphid establishment and spread after their introduction, and found that OP, host availability, and phenotypic plasticity are among the main variables underpinning the ability of aphids to succeed in new geographic areas, which may explain the high potential for invasion in this group of pest insects. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Allelopathy in agroecosystems: Wheat phytotoxicity and its possible roles in crop rotation.

    PubMed

    Lodhi, M A; Bilal, R; Malik, K A

    1987-08-01

    The germination rates of cotton and wheat seeds were significantly affected by various extracts of wheat mulch and soils collected from the wheat field. This toxicity was even more pronounced against seedling growth. Five allelochemics: ferulic,p-coumaric,p-OH benzoic, syringic, and vanillic acids, were identified from the wheat mulch and its associated soil. Quantitatively, ferulic acid was found at higher concentrations thanp-coumaric acid in the soil. Various concentrations of ferulic andp-coumaric acids were toxic to the growth of radish in a bioassay. The functional aspects of allelochemic transfer from decaying residue to soil and the subsequent microbial degradation within agroecosystems are discussed, particularly as they relate to wheat crop rotation, with wheat and cotton, in Pakistan.

  18. [Effects of plant viruses on vector and non-vector herbivorous arthropods and their natural enemies: a mini review].

    PubMed

    He, Xiao-Chan; Xu, Hong-Xing; Zhou, Xiao-Jun; Zheng, Xu-Song; Sun, Yu-Jian; Yang, Ya-Jun; Tian, Jun-Ce; Lü, Zhong-Xian

    2014-05-01

    Plant viruses transmitted by arthropods, as an important biotic factor, may not only directly affect the yield and quality of host plants, and development, physiological characteristics and ecological performances of their vector arthropods, but also directly or indirectly affect the non-vector herbivorous arthropods and their natural enemies in the same ecosystem, thereby causing influences to the whole agro-ecosystem. This paper reviewed the progress on the effects of plant viruses on herbivorous arthropods, including vector and non-vector, and their natural enemies, and on their ecological mechanisms to provide a reference for optimizing the management of vector and non-vector arthropod populations and sustainable control of plant viruses in agro-ecosystem.

  19. Termite assemblages from oil palm agroecosystems across Riau Province, Sumatra, Indonesia

    NASA Astrophysics Data System (ADS)

    Saputra, Andi; Jalaludin, Nur-Atiqah; Hazmi, Izfa Riza; Rahim, Faszly

    2016-11-01

    Termite survey was conducted at six oil palm agroecosystem sites in Riau Province, Sumatra, Indonesia to document species richness across the sites. Six sites were surveyed by using continuous transect representing gradients of oil palm landuse across Indragiri Hulu to Bengkalis District since February 5th, 2015 until May 21st, 2015. Termites were sampled by modified transect protocols (100 m × 4 m × 10 cm). A total of 23 species belonging to two families and five subfamilies were collected. The termite assemblage was dominated by wood-feeding termites. The major family collected was Rhinotermitidae which included some pest species, such as Coptotermes curvignathus, C. sepangensis, C. kalshoveni, Schedorhinotermes malaccensis, S. medioobscurus, S. brevialatus, and S. javanicus.

  20. Ecosystem services provided by agroecosystems: a qualitative and quantitative assessment of this relationship in the Pampa region, Argentina.

    PubMed

    Rositano, Florencia; Ferraro, Diego Omar

    2014-03-01

    The development of an analytical framework relating agricultural conditions and ecosystem services (ES) provision could be very useful for developing land-use systems which sustain natural resources for future use. According to this, a conceptual network was developed, based on literature review and expert knowledge, about the functional relationships between agricultural management and ES provision in the Pampa region (Argentina). We selected eight ES to develop this conceptual network: (1) carbon (C) balance, (2) nitrogen (N) balance, (3) groundwater contamination control, (4) soil water balance, (5) soil structural maintenance, (6) N2O emission control, (7) regulation of biotic adversities, and (8) biodiversity maintenance. This conceptual network revealed a high degree of interdependence among ES provided by Pampean agroecosystems, finding two trade-offs, and two synergies among them. Then, we analyzed the conceptual network structure, and found that both environmental and management variables influenced ES provision. Finally, we selected four ES to parameterize and quantify along 10 growing seasons (2000/2001-2009/2010) through a probabilistic methodology called Bayesian Networks. Only N balance was negatively impacted by agricultural management; while C balance, groundwater contamination control, and N2O emission control were not. Outcomes of our work emphasize the idea that qualitative and quantitative methodologies should be implemented together to assess ES provision in Pampean agroecosystems, as well as in other agricultural systems.

  1. Water footprint and carbon footprint of the energy consumption in sunflower agroecosystems.

    PubMed

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

    2017-08-01

    The aims of this study were to assess the energy requirements, carbon footprint, and water footprint of sunflower production in Kermanshah province, western Iran. Data were collected from 70 sunflower production agroecosystems which were selected based on random sampling method in summer 2012. Results indicated that total input and output energy in sunflower production were 26,973.87 and 64,833.92 MJha -1 , respectively. The highest share of total input energy in sunflower agroecosystems was recorded for electricity power, N fertilizer, and diesel fuel with 35, 19, and 17%, respectively. Also, energy use efficiency, water footprint, greenhouse gas (GHG) emission, and carbon footprint were calculated as 2.40, 3.41 m 3  kg -1 , 2042.091 kg CO 2eq ha -1 , and 0.875 kg CO 2eq kg -1 , respectively. 0.18 of sunflower water footprint was related to green water footprint and the remaining 82% was related to blue water footprint. Also, the highest share of carbon footprint was related to electricity power (nearby 80%). Due to the results of this study, reducing use of fossil fuel and non-renewable energy resource and application of sufficient irrigation systems by efficient use of water resource are essential in order to achieve low carbon footprint, environmental challenges, and also sustainability of agricultural production systems.

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

    PubMed

    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.

  3. Driving factors of the communities of phytophagous and predatory mites in a physic nut plantation and spontaneous plants associated.

    PubMed

    Cruz, Wilton P; Sarmento, Renato A; Teodoro, Adenir V; Neto, Marçal P; Ignacio, Maíra

    2013-08-01

    Seasonal changes in climate and plant diversity are known to affect the population dynamics of both pests and natural enemies within agroecosystems. In Brazil, spontaneous plants are usually tolerated in small-scale physic nut plantations over the year, which in turn may mediate interactions between pests and natural enemies within this agroecosystem. Here, we aimed to access the influence of seasonal variation of abiotic (temperature, relative humidity and rainfall) and biotic (diversity of spontaneous plants, overall richness and density of mites) factors on the communities of phytophagous and predatory mites found in a physic nut plantation and its associated spontaneous plants. Mite sampling was monthly conducted in dicotyledonous and monocotyledonous leaves of spontaneous plants as well as in physic nut shrubs over an entire year. In the dry season there was a higher abundance of phytophagous mites (Tenuipalpidae, Tarsonemidae and Tetranychidae) on spontaneous plants than on physic nut shrubs, while predatory mites (Phytoseiidae) showed the opposite pattern. The overall density of mites on spontaneous plants increased with relative humidity and diversity of spontaneous plants. Rainfall was the variable that most influenced the density of mites inhabiting physic nut shrubs. Agroecosystems comprising spontaneous plants associated with crops harbour a rich mite community including species of different trophic levels which potentially benefit natural pest control due to increased diversity and abundance of natural enemies.

  4. Elevated CO2 shifts the functional structure and metabolic potentials of soil microbial communities in a C4 agroecosystem.

    PubMed

    Xiong, Jinbo; He, Zhili; Shi, Shengjing; Kent, Angela; Deng, Ye; Wu, Liyou; Van Nostrand, Joy D; Zhou, Jizhong

    2015-03-20

    Atmospheric CO2 concentration is continuously increasing, and previous studies have shown that elevated CO2 (eCO2) significantly impacts C3 plants and their soil microbial communities. However, little is known about effects of eCO2 on the compositional and functional structure, and metabolic potential of soil microbial communities under C4 plants. Here we showed that a C4 maize agroecosystem exposed to eCO2 for eight years shifted the functional and phylogenetic structure of soil microbial communities at both soil depths (0-5 cm and 5-15 cm) using EcoPlate and functional gene array (GeoChip 3.0) analyses. The abundances of key genes involved in carbon (C), nitrogen (N) and phosphorus (P) cycling were significantly stimulated under eCO2 at both soil depths, although some differences in carbon utilization patterns were observed between the two soil depths. Consistently, CO2 was found to be the dominant factor explaining 11.9% of the structural variation of functional genes, while depth and the interaction of depth and CO2 explained 5.2% and 3.8%, respectively. This study implies that eCO2 has profound effects on the functional structure and metabolic potential/activity of soil microbial communities associated with C4 plants, possibly leading to changes in ecosystem functioning and feedbacks to global change in C4 agroecosystems.

  5. Organic farming favours insect-pollinated over non-insect pollinated forbs in meadows and wheat fields.

    PubMed

    Batáry, Péter; Sutcliffe, Laura; Dormann, Carsten F; Tscharntke, Teja

    2013-01-01

    The aim of this study was to determine the relative effects of landscape-scale management intensity, local management intensity and edge effect on diversity patterns of insect-pollinated vs. non-insect pollinated forbs in meadows and wheat fields. Nine landscapes were selected differing in percent intensively used agricultural area (IAA), each with a pair of organic and conventional winter wheat fields and a pair of organic and conventional meadows. Within fields, forbs were surveyed at the edge and in the interior. Both diversity and cover of forbs were positively affected by organic management in meadows and wheat fields. This effect, however, differed significantly between pollination types for species richness in both agroecosystem types (i.e. wheat fields and meadows) and for cover in meadows. Thus, we show for the first time in a comprehensive analysis that insect-pollinated plants benefit more from organic management than non-insect pollinated plants regardless of agroecosystem type and landscape complexity. These benefits were more pronounced in meadows than wheat fields. Finally, the community composition of insect-pollinated and non-insect-pollinated forbs differed considerably between management types. In summary, our findings in both agroecosystem types indicate that organic management generally supports a higher species richness and cover of insect-pollinated plants, which is likely to be favourable for the density and diversity of bees and other pollinators.

  6. Organic Farming Favours Insect-Pollinated over Non-Insect Pollinated Forbs in Meadows and Wheat Fields

    PubMed Central

    Batáry, Péter; Sutcliffe, Laura; Dormann, Carsten F.; Tscharntke, Teja

    2013-01-01

    The aim of this study was to determine the relative effects of landscape-scale management intensity, local management intensity and edge effect on diversity patterns of insect-pollinated vs. non-insect pollinated forbs in meadows and wheat fields. Nine landscapes were selected differing in percent intensively used agricultural area (IAA), each with a pair of organic and conventional winter wheat fields and a pair of organic and conventional meadows. Within fields, forbs were surveyed at the edge and in the interior. Both diversity and cover of forbs were positively affected by organic management in meadows and wheat fields. This effect, however, differed significantly between pollination types for species richness in both agroecosystem types (i.e. wheat fields and meadows) and for cover in meadows. Thus, we show for the first time in a comprehensive analysis that insect-pollinated plants benefit more from organic management than non-insect pollinated plants regardless of agroecosystem type and landscape complexity. These benefits were more pronounced in meadows than wheat fields. Finally, the community composition of insect-pollinated and non-insect-pollinated forbs differed considerably between management types. In summary, our findings in both agroecosystem types indicate that organic management generally supports a higher species richness and cover of insect-pollinated plants, which is likely to be favourable for the density and diversity of bees and other pollinators. PMID:23382979

  7. Climate change induced rainfall patterns affect wheat productivity and agroecosystem functioning dependent on soil types

    NASA Astrophysics Data System (ADS)

    Tabi Tataw, James; Baier, Fabian; Krottenthaler, Florian; Pachler, Bernadette; Schwaiger, Elisabeth; Whylidal, Stefan; Formayer, Herbert; Hösch, Johannes; Baumgarten, Andreas; Zaller, Johann G.

    2014-05-01

    Wheat is a crop of global importance supplying more than half of the world's population with carbohydrates. We examined, whether climate change induced rainfall patterns towards less frequent but heavier events alter wheat agroecosystem productivity and functioning under three different soil types. Therefore, in a full-factorial experiment Triticum aestivum L. was cultivated in 3 m2 lysimeter plots containing the soil types sandy calcaric phaeozem, gleyic phaeozem or calcic chernozem. Prognosticated rainfall patterns based on regionalised climate change model calculations were compared with current long-term rainfall patterns; each treatment combination was replicated three times. Future rainfall patterns significantly reduced wheat growth and yield, reduced the leaf area index, accelerated crop development, reduced arbuscular mycorrhizal fungi colonisation of roots, increased weed density and the stable carbon isotope signature (δ13C) of both old and young wheat leaves. Different soil types affected wheat growth and yield, ecosystem root production as well as weed abundance and biomass. The interaction between climate and soil type was significant only for the harvest index. Our results suggest that even slight changes in rainfall patterns can significantly affect the functioning of wheat agroecosystems. These rainfall effects seemed to be little influenced by soil types suggesting more general impacts of climate change across different soil types. Wheat production under future conditions will likely become more challenging as further concurrent climate change factors become prevalent.

  8. Ecohydrological modeling in agroecosystems: Examples and challenges

    DOE PAGES

    Porporato, A.; Feng, X.; Manzoni, S.; ...

    2015-06-01

    We report that 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 themore » 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. Finally, 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.« less

  9. Emmonsiosis of rodents in an agroecosystem.

    PubMed

    Hubálek, Z; Nesvadbová, J; Halouzka, J

    1998-12-01

    Adiaspores of Emmonsia crescens were found in the lungs of 62.1% of 87 adult rodents from 10 windbreaks compared to only 8.2% of 184 adult rodents caught in 10 adjacent arable fields in South Moravia, Czechland. A significantly higher mean weight proportion of plant remnants (predominantly small roots) was present in the soil from windbreaks (0.74%) than from fields (0.24%). In addition, mean relative abundance of rodents was significantly higher in windbreaks than in fields, and the windbreak soil was more acidic (pH 6.2 vs. 6.9, respectively). On the other hand, there was no significant difference in the water content (17.4% vs. 18.5%, respectively). The difference in the infection rate between the two habitats of the agroecosystem could be caused or affected by land use and farming technology.

  10. Plant Functional Traits: Soil and Ecosystem Services.

    PubMed

    Faucon, Michel-Pierre; Houben, David; Lambers, Hans

    2017-05-01

    Decline of ecosystem services has triggered numerous studies aiming at developing more sustainable agricultural management practices. Some agricultural practices may improve soil properties by expanding plant biodiversity. However, sustainable management of agroecosystems should be performed from a functional plant trait perspective. Advances in functional ecology, especially plant functional trait effects on ecosystem processes and services, provide pivotal knowledge for ecological intensification of agriculture; this approach acknowledges that a crop field is an agroecosystem whose ecological processes influence soil properties. We highlight the links between plant functional traits and soil properties in relation to four major ecosystem processes involved in vital ecosystem services: food production, crop protection, climate change mitigation, and soil and water conservation, aiming towards ecological intensification of sustainable agricultural and soil management. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    NASA Technical Reports Server (NTRS)

    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.

  12. Agroecology in the tropics: Achieving a balance between land use and preservation

    NASA Astrophysics Data System (ADS)

    Gliessman, Stephen R.

    1992-11-01

    Agroecology is the application of ecological concepts and principles to the design and management of sustainable agricultural systems. An agroecological approach to agriculture has special importance in the humid tropics where agricultural development and the preservation of tropical forests are most often in direct conflict. It is proposed that a more sustainable approach to development is needed, where agroecosystems depend on low external inputs, function more on the use of locally available and renewable resources, have benign impacts on the environment, and are based on the knowledge and culture of the local inhabitants. Examples of traditional agroecosystem management in Mesoamerica that can provide this basis are presented. The preservation of both biological and cultural diversity are integral to the long-term sustainable management of natural resources in the tropics.

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

    PubMed

    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.

  14. Functionally ecological assessment of C dominant pools and fluxes in field agroecosystems with sod-podzoluvosols at the Central Region of Russia

    NASA Astrophysics Data System (ADS)

    Mazirov, Ilya; Vizirskaya, Mariya; Epikhina, Anna; Vasenev, Ivan; Valentini, Riccardo; Meshalkina, Julia

    2014-05-01

    The Global Change problem has obvious interaction with greenhouse gases (GHG) emission. The principal GHG is carbon dioxide. There is a lot of data on its fluxes but the Central Region of Russia is still one of less investigated area especially in case of agroecosystem carbon dioxide fluxes monitoring by chambers and eddy covariance methods combined application. Our research has been at the representative key plots of cultivated sod-podzoluvosols located at the Precision Farming Experimental Field of the Russian Timiryazev State Agricultural University (Moscow) in 2012-2013 in frame of RF Government grant 11.G34.31.0079 and RFBR grant 11-04-01376 activities. The research include the detailed soil cover patterns morphogenetic investigation, soil C pools dynamic analysis, soil CO2 flux decade-based monitoring by method of exposition chambers with IRGA (infra red gas analyzer) and agroecosystem CO2 flux seasonal monitoring by two eddy covariance stations in frame of 4 ha experimental plot. There were two crop versions (barley and grass mixture), and in case of chamber analysis - also two agrotecnology versions (traditional and no-till ones) with soil temperature and moisture analysis too. The results have shown high daily and seasonal dynamic of soil and agroecosystem CO2 emission. The beginning of vegetation period (until plant height of 10-12 cm) is characterized by high average soil CO2 emission and adsorption at the same time. The adsorption is significantly higher. The resulted CO2 absorption during the day is approximately two times higher than emissions at night. After harvesting CO2 emission is becoming essentially higher than adsorption. In 2012 data have shown for barley the small predominance of CO2 emissions over the absorption. The daily dynamics of soil CO2 emissions depends on the air temperature dynamics with the correlation coefficient changes from 0.86 at the beginning of the season to 0.52 and 0.38 at the middle and at the end of one. Soil moisture has stronger influence on the seasonal dynamics of soil and agroecosystem CO2 emissions. The crop factor input is stronger that the agro technology one. According to the obtained results it is especially important to carry out the soil CO2 emission measurement at the same time period during the day (the best one is between 11 and 15) due to high changes in CO2 emission during the 24 hours period - especially at the beginning of the summer. At the end of the season the influence of the temperature daily dynamics is becoming not so significant for CO2 emission monitoring.

  15. Modelling Crop Biocontrol by Wanderer Spiders

    NASA Astrophysics Data System (ADS)

    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.

  16. Hydrogeochemistry of the Overland Flow in Soil at Agroecosystems in Eastern Amazon

    NASA Astrophysics Data System (ADS)

    Costa, C. F. G. D.; Figueiredo, R. O.; Oliveira, F. D. A.

    2014-12-01

    In the watershed of the Timboteua and Buiuna streams, northeast of Pará state, Amazon, it was characterized the overland flow dissolved material by some hydrogeochemical variables: electrical conductivity (EC), pH, chloride (Cl-), nitrate (NO3-), phosphate (PO43-), and sulfate (SO42-). In two small holder properties three overland flow experimental plots (1m2) were placed in each of the six evaluated ecosystems under similar biophysical conditions, totaling 18 plots. There was also installed three rainwater collectors and two rain gauges in a nearby area. In the rainy season were collected 234 samples of rainwater and overland flow. The evaluation of the measured variables promote the hydrogeochemical characterization of the overland flow at soil under chop-and-mulch and slash-and-burn practices in the different ecosystems found in the familiar agriculture of this watershed, in which it was identified some distinct hydrogeochemical characteristics of the overland flow. The lowest losses of NO3- (variation range = 0.07 to 2.57 μM) was found in agroecosystem - chop-and-mulch, this nutrient obtained higher values in agroecosystem - slash-and-burn (RQ). In agroecosystem (RQ) initially, there was a high value of PO43- (8.87 μM); EC (121 μS cm-1) and a subsequent sharp decline. Secondary successional forest (CP) of 20 years presented in overland flow pH 4.8 and EC 25 μS cm-1 (average 6 months), low loss of NO3- (0.2 μM) and PO43- (0.05 μM), and large range of variation of SO42- (0.7 to 21.5 μM). While Cl- and SO42- overland flow concentrations were affect by the rainfall variation, the increase of NO3- and PO43-concentrations were more related to the ecosystem management, with the first element responding to the presence of nitrogen-fixing species and the second responding to the burning practices. In summary: This study was efficient to characterize the hydrogeochemical of the overland flow and its relation to the altered ecosystems by Amazonian family farming.

  17. Atmospheric deposition as an important nitrogen load to a typical agro-ecosystem in the Huang-Huai-Hai Plain. 2. Seasonal and inter-annual variations and their implications (2008-2012)

    NASA Astrophysics Data System (ADS)

    Huang, Ping; Zhang, Jiabao; Ma, Donghao; Wen, Zhaofei; Wu, Shengjun; Garland, Gina; Pereira, Engil Isadora Pujol; Zhu, Anning; Xin, Xiuli; Zhang, Congzhi

    2016-03-01

    Atmospheric nitrogen (N) deposition, an important N source to agro-ecosystems, has increased intensively in China during recent decades. However, knowledge on temporal variations of total N deposition and their influencing factors is limited due to lack of systematic monitoring data. In this study, total N deposition, including dry and wet components, was monitored using the water surrogate surface method for a typical agro-ecosystem with a winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) rotation system in the Huang-Huai-Hai Plain from May 2008 to April 2012. The results indicated that annual total N deposition ranged from 23.8 kg N ha-1 (2009-2010) to 40.3 kg N ha-1 (2008-2009) and averaged 31.8 kg N ha-1. Great inter-annual variations were observed during the sampling period, due to differences in annual rainfall and gaseous N losses from farmlands. Monthly total N deposition varied greatly, from less than 0.6 kg N ha-1 (January, 2010) to over 8.0 kg N ha-1 (August, 2008), with a mean value of 2.6 kg N ha-1. In contrast to wet deposition, dry portions generally contributed more to the total, except in the precipitation-intensive months, accounting for 65% in average. NH4+ -N was the dominant species in N deposition and its contribution to total deposition varied from 6% (December, 2009) to 79% (July, 2008), averaging 53%. The role of organic N (O-N) in both dry and wet deposition was equal to or even greater than that of NO3- -N. Influencing factors such as precipitation and its seasonal distribution, reactive N sources, vegetation status, field management practices, and weather conditions were responsible for the temporal variations of atmospheric N deposition and its components. These results are helpful for reducing the knowledge gaps in the temporal variations of atmospheric N deposition and their influencing factors in different ecosystems, to improve the understandings on N budget in the typical agro-ecosystem, and to provide references and recommendations for field nutrient management in this region.

  18. Agroecology in the tropics: Achieving a balance between land use and preservation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gliessman, S.R.

    Agroecology is the application of ecological concepts and principles to the design and management of sustainable agricultural systems. An agroecological approach to agriculture has special importance in the humid tropics where agricultural development and the preservation of tropical forests are most often in direct conflict. It is proposed that a more sustainable approach to development is needed, where agroecosystems depend on low external inputs, function more on the use of locally available and renewable resources, have benign impacts on the environment, and are based on the knowledge and culture of the local inhabitants. Examples of traditional agroecosystem management in Mesoamericamore » that can provide this basis are presented. The preservation of both biological and cultural diversity are integral to the long-term sustainable management of natural resources in the tropics.« less

  19. Rapid evolution in insect pests: the importance of space and time in population genomics studies.

    PubMed

    Pélissié, Benjamin; Crossley, Michael S; Cohen, Zachary Paul; Schoville, Sean D

    2018-04-01

    Pest species in agroecosystems often exhibit patterns of rapid evolution to environmental and human-imposed selection pressures. Although the role of adaptive processes is well accepted, few insect pests have been studied in detail and most research has focused on selection at insecticide resistance candidate genes. Emerging genomic datasets provide opportunities to detect and quantify selection in insect pest populations, and address long-standing questions about mechanisms underlying rapid evolutionary change. We examine the strengths of recent studies that stratify population samples both in space (along environmental gradients and comparing ancestral vs. derived populations) and in time (using chronological sampling, museum specimens and comparative phylogenomics), resulting in critical insights on evolutionary processes, and providing new directions for studying pests in agroecosystems. Copyright © 2018 Elsevier Inc. All rights reserved.

  20. Paisang (Quercus griffithii): a keystone tree species in sustainable agroecosystem management and livelihoods in Arunachal Pradesh, India.

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Elevated CO2 shifts the functional structure and metabolic potentials of soil microbial communities in a C4 agroecosystem

    PubMed Central

    Xiong, Jinbo; He, Zhili; Shi, Shengjing; Kent, Angela; Deng, Ye; Wu, Liyou; Van Nostrand, Joy D.; Zhou, Jizhong

    2015-01-01

    Atmospheric CO2 concentration is continuously increasing, and previous studies have shown that elevated CO2 (eCO2) significantly impacts C3 plants and their soil microbial communities. However, little is known about effects of eCO2 on the compositional and functional structure, and metabolic potential of soil microbial communities under C4 plants. Here we showed that a C4 maize agroecosystem exposed to eCO2 for eight years shifted the functional and phylogenetic structure of soil microbial communities at both soil depths (0–5 cm and 5–15 cm) using EcoPlate and functional gene array (GeoChip 3.0) analyses. The abundances of key genes involved in carbon (C), nitrogen (N) and phosphorus (P) cycling were significantly stimulated under eCO2 at both soil depths, although some differences in carbon utilization patterns were observed between the two soil depths. Consistently, CO2 was found to be the dominant factor explaining 11.9% of the structural variation of functional genes, while depth and the interaction of depth and CO2 explained 5.2% and 3.8%, respectively. This study implies that eCO2 has profound effects on the functional structure and metabolic potential/activity of soil microbial communities associated with C4 plants, possibly leading to changes in ecosystem functioning and feedbacks to global change in C4 agroecosystems. PMID:25791904

  3. Biodiversity conservation in an anthropized landscape: Trees, not patch size drive, bird community composition in a low-input agro-ecosystem.

    PubMed

    Mellink, Eric; Riojas-López, Mónica E; Cárdenas-García, Melinda

    2017-01-01

    One of the most typical agro-ecosystems in the Llanos de Ojuelos, a semi-arid region of central Mexico, is that of fruit-production orchards of nopales (prickly pear cacti). This perennial habitat with complex vertical structure provides refuge and food for at least 112 species of birds throughout the year. Nopal orchards vary in their internal structure, size and shrub/tree composition, yet these factors have unknown effects on the animals that use them. To further understand the conservation potential of this agro-ecosystem, we evaluated the effects of patch-size and the presence of trees on bird community composition, as well as several habitat variables, through an information-theoretical modelling approach. Community composition was obtained through a year of census transects in 12 orchards. The presence of trees in the orchards was the major driver of bird communities followed by seasonality; bird communities are independent of patch size, except for small orchard patches that benefit black-chin sparrows, which are considered a sensitive species. At least 55 species of six trophic guilds (insectivores, granivores, carnivores, nectivores, omnivores, and frugivores) used the orchards. Orchards provide adequate habitat and food resources for several sensitive species of resident and migratory sparrows. The attributes that make orchards important for birds: trees, shrubs, herb seeds, and open patches can be managed to maintain native biodiversity in highly anthropized regions with an urgent need to find convergence between production and biological conservation.

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

    PubMed

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

    2016-02-01

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

  5. Biodiversity conservation in an anthropized landscape: Trees, not patch size drive, bird community composition in a low-input agro-ecosystem

    PubMed Central

    Mellink, Eric; Cárdenas-García, Melinda

    2017-01-01

    One of the most typical agro-ecosystems in the Llanos de Ojuelos, a semi-arid region of central Mexico, is that of fruit-production orchards of nopales (prickly pear cacti). This perennial habitat with complex vertical structure provides refuge and food for at least 112 species of birds throughout the year. Nopal orchards vary in their internal structure, size and shrub/tree composition, yet these factors have unknown effects on the animals that use them. To further understand the conservation potential of this agro-ecosystem, we evaluated the effects of patch-size and the presence of trees on bird community composition, as well as several habitat variables, through an information-theoretical modelling approach. Community composition was obtained through a year of census transects in 12 orchards. The presence of trees in the orchards was the major driver of bird communities followed by seasonality; bird communities are independent of patch size, except for small orchard patches that benefit black-chin sparrows, which are considered a sensitive species. At least 55 species of six trophic guilds (insectivores, granivores, carnivores, nectivores, omnivores, and frugivores) used the orchards. Orchards provide adequate habitat and food resources for several sensitive species of resident and migratory sparrows. The attributes that make orchards important for birds: trees, shrubs, herb seeds, and open patches can be managed to maintain native biodiversity in highly anthropized regions with an urgent need to find convergence between production and biological conservation. PMID:28686608

  6. Reduced greenhouse gas mitigation potential of no-tillage soils through earthworm activity

    PubMed Central

    Lubbers, Ingrid M.; Jan van Groenigen, Kees; Brussaard, Lijbert; van Groenigen, Jan Willem

    2015-01-01

    Concerns about rising greenhouse gas (GHG) concentrations have spurred the promotion of no-tillage practices as a means to stimulate carbon storage and reduce CO2 emissions in agro-ecosystems. Recent research has ignited debate about the effect of earthworms on the GHG balance of soil. It is unclear how earthworms interact with soil management practices, making long-term predictions on their effect in agro-ecosystems problematic. Here we show, in a unique two-year experiment, that earthworm presence increases the combined cumulative emissions of CO2 and N2O from a simulated no-tillage (NT) system to the same level as a simulated conventional tillage (CT) system. We found no evidence for increased soil C storage in the presence of earthworms. Because NT agriculture stimulates earthworm presence, our results identify a possible biological pathway for the limited potential of no-tillage soils with respect to GHG mitigation. PMID:26337488

  7. Floral resource availability from groundcover promotes bee abundance in coffee agroecosystems.

    PubMed

    Fisher, Kaleigh; Gonthier, David J; Ennis, Katherine K; Perfecto, Ivette

    2017-09-01

    Patterns of bee abundance and diversity across different spatial scales have received thorough research consideration. However, the impact of short- and long-term temporal resource availability on biodiversity has been less explored. This is highly relevant in tropical agricultural systems for pollinators, as many foraging periods of pollinators extend beyond flowering of any single crop species. In this study, we sought to understand how bee communities in tropical agroecosystems changed between seasons, and if short- and long-term floral resource availability influenced their diversity and abundance. We used a threshold analysis approach in order to explore this relationship at two time scales. This study took place in a region dominated by coffee agroecosystems in Southern Mexico. This was an ideal system because the landscape offers a range of coffee management regimes that maintain heterogeneity in floral resource availability spatially and temporally. We found that the bee community varies significantly between seasons. There were higher abundances of native social, solitary and managed honey bees during the dry season when coffee flowers. Additionally, we found that floral resources from groundcover, but not trees, were associated with bee abundance. Further, the temporal scale of the availability of these resources is important, whereby short-term floral resource availability appears particularly important in maintaining high bee abundance at sites with lower seasonal complementarity. We argue that in addition to spatial resource heterogeneity, temporal resource heterogeneity is critical in explaining bee community patterns, and should thus be considered to promote pollinator conservation. © 2017 by the Ecological Society of America.

  8. Abnormalities in amphibian populations inhabiting agroecosystems in Northeastern Buenos Aires Province, Argentina.

    PubMed

    Agostini, M G; Kacoliris, F; Demetrio, P; Natale, G S; Bonetto, C; Ronco, A E

    2013-05-27

    The occurrence of abnormalities in amphibians has been reported in many populations, and its increase could be related to environmental pollution and habitat degradation. We evaluated the type and prevalence of abnormalities in 5 amphibian populations from agroecosystems with different degrees of agricultural disturbance (cultivated and reference areas). We detected 9 types of abnormalities, of which the most frequent were those occurring in limbs. The observed prevalence of abnormality in assessed populations from cultivated and reference areas was as follows: Rhinella fernandezae (37.1 and 10.2%, respectively), Leptodactylus latrans adults (28.1 and 9.2%) and juveniles (32.9 and 15.3%), and Hypsiboas pulchellus (11.6 and 2.8%). Scinax granulatus populations did not show abnormalities. Pseudis minuta, which was only detected in the reference area, exhibited a prevalence of 13.3%. For R. fernandezae, L. latrans, and H. pulchellus, generalized linear mixed models showed that prevalence of abnormalities was significantly higher (p < 0.05) in cultivated than in reference areas. L. latrans juveniles were more vulnerable to abnormalities than adults (p < 0.05). The presence of abnormalities in some species inhabiting different agroecosystems suggests that environmental stress factors might be responsible for their occurrence. While we detected pesticides (endosulfan, cypermethrin, and chlorpyrifos) and lower dissolved oxygen levels in ponds of the cultivated area, no data are currently available on how other factors, such as injuries from predators and parasite infections, vary by land use. Further research will be necessary to evaluate possible causes of abnormalities detected in the present study mainly in the context of factor interactions.

  9. Rain forest promotes trophic interactions and diversity of trap-nesting Hymenoptera in adjacent agroforestry.

    PubMed

    Klein, Alexandra-Maria; Steffan-Dewenter, Ingolf; Tscharntke, Teja

    2006-03-01

    1. Human alteration of natural ecosystems to agroecosystems continues to accelerate in tropical countries. The resulting world-wide decline of rain forest causes a mosaic landscape, comprising simple and complex agroecosystems and patchily distributed rain forest fragments of different quality. Landscape context and agricultural management can be expected to affect both species diversity and ecosystem services by trophic interactions. 2. In Central Sulawesi, Indonesia, 24 agroforestry systems, differing in the distance to the nearest natural forest (0-1415 m), light intensity (37.5-899.6 W/m(-2)) and number of vascular plant species (7-40 species) were studied. Ten standardized trap nests for bees and wasps, made from reed and knotweed internodes, were exposed in each study site. Occupied nests were collected every month, over a period totalling 15 months. 3. A total of 13,617 brood cells were reared to produce adults of 14 trap-nesting species and 25 natural enemy species, which were mostly parasitoids. The total number of species was affected negatively by increasing distance from forest and increased with light intensity of agroforestry systems. The parasitoids in particular appeared to benefit from nearby forests. Over a 500-m distance, the number of parasitoid species decreased from eight to five, and parasitism rates from 12% to 4%. 4. The results show that diversity and parasitism, as a higher trophic interaction and ecosystem service, are enhanced by (i) improved connectivity of agroecosystems with natural habitats such as agroforestry adjacent to rain forest and (ii) management practices to increase light availability in agroforestry, which also enhances richness of flowering plants in the understorey.

  10. Predicting the global warming potential of agro-ecosystems

    NASA Astrophysics Data System (ADS)

    Lehuger, S.; Gabrielle, B.; Larmanou, E.; Laville, P.; Cellier, P.; Loubet, B.

    2007-04-01

    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.

  11. Atmospheric wet deposition of nitrogen and sulfur to a typical red soil agroecosystem in Southeast China during the ten-year monsoon seasons (2003-2012)

    NASA Astrophysics Data System (ADS)

    Cui, Jian; Zhou, Jing; Peng, Ying; He, Yuanqiu; Yang, Hao; Mao, Jingdong

    2014-01-01

    Biological processes in agroecosystems have been affected by atmospheric nitrogen (N) and sulfur (S) deposition, but there is uncertainty about their deposition characteristics in the monsoon season. We collected rain samples using an ASP-2 sampler, recorded rainfall and rain frequency by an auto-meteorological experiment sub-station, and determined total N, NO3--N and NH4+-N levels in precipitation with an AutoAnalyzer 3 and SO42--S with a chromatography, in order to characterize the wet deposition of N and S to a typical red soil agroecosystem by a ten-year monitoring experiment in Southeast China. The results indicated that N and S wet deposition had an increased trend with the flux of total N (3.34-65.17 kg ha-1 N) and total S (SO42--S) (7.17-23.44 kg ha-1 S) during the monsoon seasons. The additional applications of pig mature in 2006 and 2007 led to the peaks of DON (dissolved organic nitrogen) and total N wet deposition. On average, NH4+-N was the major N form, accounting for 48.5% of total N wet deposition and DON was not a negligible N form, accounting for 20.8% during the ten-year monsoon seasons (except 2006 and 2007). Wet deposition of N and S has been intensively influenced by human activities in the monsoon season, and would increase the potential ecological risk in the red soil agricultural ecosystem.

  12. INDIVIDUAL AND POPULATION RESPONSES TO ABIOTIC STRESSES IN ITALIAN RYEGRASS

    EPA Science Inventory

    Expected changes in environmental factors will alter productivity of agroecosystems and influence the distribution of agricultural pests. In addition to the natural factors that cause stress, humans introduce chemical pesticides into the agricultural environment. Weeds persist in...

  13. Open software tools for eddy covariance flux partitioning

    USDA-ARS?s Scientific Manuscript database

    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...

  14. MOLECULAR GENETIC APPROACHES TO PEST AND NONTARGET POPULATION MONITORING

    EPA Science Inventory

    The U.S. Environmental Protection Agency has interest in a number of applications of genetic monitoring methodologies. Genetic monitoring in agroecosystems can provide valuable environmental information regarding both traditional and novel pesticides. One group of pesticides of...

  15. Generation of multi annual land use and crop rotation data for regional agro-ecosystem modeling

    NASA Astrophysics Data System (ADS)

    Waldhoff, G.; Lussem, U.; Sulis, M.; Bareth, G.

    2017-12-01

    For agro-ecosystem modeling on a regional scale with systems like the Community Land Model (CLM), detailed crop type and crop rotation information on the parcel-level is of key importance. Only with this, accurate assessments of the fluxes associated with the succession of crops and their management are possible. However, sophisticated agro-ecosystem modeling for large regions is only feasible at grid resolutions, which are much coarser than the spatial resolution of modern land use maps (usually ca. 30 m). As a result, much of the original information content of the maps has to be dismissed during resampling. Here we present our mapping approach for the Rur catchment (located in the west of Germany), which was developed to address these demands and issues. We integrated remote sensing and geographic information system (GIS) methods to classify multi temporal images of (e.g.) Landsat, RapidEye and Sentinel-2 to generate annual crop maps for the years 2008-2017 at 15 m spatial resolution (accuracy always ca. 90 %). A key aspect of our method is the consideration of crop phenology for the data selection and the analysis. In a GIS, the annul crop maps were integrated to a crop sequence dataset from which the major crop rotations were derived (based on the 10-years). To retain the multi annual crop succession and crop area information at coarser grid resolutions, cell-based land use fractions, including other land use classes were calculated for each year and for various target cell sizes (1-32 arc seconds). The resulting datasets contain the contribution (in percent) of every land use class to each cell. Our results show that parcels with the major crop types can be differentiated with a high accuracy and on an annual basis. The analysis of the crop sequence data revealed a very large number of different crop rotations, but only relatively few crop rotations cover larger areas. This strong diversity emphasizes the importance of information on crop rotations to reduce uncertainties in agro-ecosystem modeling. Through the combination of the multi annual land use fractions, the resulting datasets additionally inform about land use changes and trends within the coarser grid cells. We see this as a major advantage, because we are able to maintain much more precise land use information when a coarser cell size is used.

  16. Impact of crop residue management on crop production and soil chemistry after seven years of crop rotation in temperate climate, loamy soils.

    PubMed

    Hiel, Marie-Pierre; Barbieux, Sophie; Pierreux, Jérôme; Olivier, Claire; Lobet, Guillaume; Roisin, Christian; Garré, Sarah; Colinet, Gilles; Bodson, Bernard; Dumont, Benjamin

    2018-01-01

    Society is increasingly demanding a more sustainable management of agro-ecosystems in a context of climate change and an ever growing global population. The fate of crop residues is one of the important management aspects under debate, since it represents an unneglectable quantity of organic matter which can be kept in or removed from the agro-ecosystem. The topic of residue management is not new, but the need for global conclusion on the impact of crop residue management on the agro-ecosystem linked to local pedo-climatic conditions has become apparent with an increasing amount of studies showing a diversity of conclusions. This study specifically focusses on temperate climate and loamy soil using a seven-year data set. Between 2008 and 2016, we compared four contrasting residue management strategies differing in the amount of crop residues returned to the soil (incorporation vs. exportation of residues) and in the type of tillage (reduced tillage (10 cm depth) vs. conventional tillage (ploughing at 25 cm depth)) in a field experiment. We assessed the impact of the crop residue management on crop production (three crops-winter wheat, faba bean and maize-cultivated over six cropping seasons), soil organic carbon content, nitrate ([Formula: see text]), phosphorus (P) and potassium (K) soil content and uptake by the crops. The main differences came primarily from the tillage practice and less from the restitution or removal of residues. All years and crops combined, conventional tillage resulted in a yield advantage of 3.4% as compared to reduced tillage, which can be partly explained by a lower germination rate observed under reduced tillage, especially during drier years. On average, only small differences were observed for total organic carbon (TOC) content of the soil, but reduced tillage resulted in a very clear stratification of TOC and also of P and K content as compared to conventional tillage. We observed no effect of residue management on the [Formula: see text] content, since the effect of fertilization dominated the effect of residue management. To confirm the results and enhance early tendencies, we believe that the experiment should be followed up in the future to observe whether more consistent changes in the whole agro-ecosystem functioning are present on the long term when managing residues with contrasted strategies.

  17. Energy balances in sugar cane, coffee and natural vegetation in the northeastern side of the São Paulo state, Brazil

    NASA Astrophysics Data System (ADS)

    de C. Teixeira, Antônio H.; Leivas, Janice F.; Ronquim, Carlos C.; Bayma-Silva, Gustavo; de C. Victoria, Daniel

    2016-10-01

    Under land and climate change scenarios, agriculture has experienced water competitions among other sectors in the São Paulo state, Brazil. On the one hand, in several occasions, in the northeastern side of this state, nowadays sugar-cane is expanding, while coffee plantations are losing space. On the other hand, both crops have replaced the natural vegetation composed by Savannah and Atlantic Coastal Forest species. Under this dynamic situation, geosciences are valuable tools for evaluating the large-scale energy and mass exchanges between these different agro-ecosystems and the lower atmosphere. For quantification of the energy balance components in these mixed agro-ecosystems, the bands 1 and 2 from the MODIS product MOD13Q1 were used throughout SAFER (Surface Algorithm for Evapotranspiration Retrieving) algorithm, which was applied together with a net of 12 automatic weather stations, during the year 2015 in the main sugar cane and coffee growing regions, located at the northeastern side of the state. The fraction of the global solar radiation (RG) transformed into net radiation (Rn) was 52% for sugar cane and 53% for both, coffee and natural vegetation. The respective annual fractions of Rn used as λE were 0.68, 0.87 and 0.77, while for the sensible heat (H) fluxes they were 0.27, 0.07 and 0.16. From April to July, heat advection raised λE values above Rn promoting negative H, however these effects were much and less strong in coffee and sugar cane crops, respectively. The smallest daily Rn fraction for all agro-ecosystems was for the soil heat flux (G), with averages of 5%, 6% and 7% in sugar cane, coffee and natural vegetation. From the energy balance analyses, we could conclude that, sugar-cane crop presented lower annual water consumption than that for coffee crop, what can be seen as an advantage in situations of water scarcity. However, the replacement of natural vegetation by sugar cane can contribute for warming the environment, while when this occur with coffee crop there was noticed cooling conditions. The large scale modeling satisfactory results confirm the suitability of using MODIS products together with weather stations to study the energy balance components in mixed agro-ecosystems under land-use and climate change conditions.

  18. An immunological approach to distinguish arthropod vivaphagy from necrophagy

    USDA-ARS?s Scientific Manuscript database

    Scavenging activity of predators inhabiting agroecosystems has not been thorough investigated. Understanding the prevalence of necrophagy in predators is paramount to determining the effectiveness of biological control agents. A molecular predator gut content assay is described that can differentiat...

  19. Landscape contexts and commonalities: building the LTAR network

    USDA-ARS?s Scientific Manuscript database

    The United States Department of Agriculture has established a Long-Term Agroecosystem Research Network to provide a coordinated framework to, “Enable understanding and forecasting of regional landscape capacities to provide agricultural commodities and ecosystem services under changing conditions.” ...

  20. Tall fescue management in the Piedmont: Sequestration of soil organic and total nitrogen

    USDA-ARS?s Scientific Manuscript database

    High quality soil-surface characteristics are important for developing environmentally sustainable agroecosystems. We evaluated the factorial combination of fertilization regime (inorganic and broiler litter) and tall fescue [Lolium arundinaceum (Schreb.) Darbysh.]-endophyte association (free, nove...

  1. LEACHING MODELS FOR SUBSURFACE POLLUTION ASSESSMENT IN AGROECOSYSTEMS

    EPA Science Inventory

    Unrestricted use of pesticides in agriculture threatens ground-water resources and can have adverse ecological impact on the nation's receiving surface waters. In this paper, we develop mass fraction models for exposure assessment and the regulation of agricultural organic chemic...

  2. Snapshots of biodiversity in Georgia agroecosystems

    USDA-ARS?s Scientific Manuscript database

    Georgia agricultural landscapes are composed of a diversity of commodities. Here we present biodiversity and biotic interaction data from multiple agricultural systems including: cotton, corn, peanut, blueberry and non-cropping wildflower areas over multiple years. Our goal is to better understand t...

  3. Agroecosystems & Environment | National Agricultural Library

    Science.gov Websites

    Skip to main content Home National Agricultural Library United States Department of Agriculture Ag useful formats (maps, tables, graphs), Agricultural Products html Useful to Usable: Developing usable integrated expertise in applied climatology, crop modeling, agronomy, cyber-technology, agricultural

  4. Ecological enrichment in agroecosystems: Utilizing wildflowers to promote beneficial arthropod communities

    USDA-ARS?s Scientific Manuscript database

    Beneficial arthropods which provide important ecosystems services have come under threat as a result of intensive agricultural practices and landscape simplification. Engineering diverse heterogeneous agricultural landscapes to provide optimal resources for beneficial arthropods may recover and enha...

  5. Agricultural geophysics: Past/present accomplishments and future advancements

    USDA-ARS?s Scientific Manuscript database

    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...

  6. Systems approach critical to agroecosystems management

    USDA-ARS?s Scientific Manuscript database

    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-...

  7. Mechanistic modeling of insecticide risks to breeding birds in North American agroecosystems

    EPA Science Inventory

    Insecticide usage in the United States is ubiquitous in urban, suburban, and rural environments. In evaluating data for an insecticide registration application and for registration review, scientists at the United States Environmental Protection Agency (USEPA) assess the fate of ...

  8. Soil agroecosystem health: current challenges and future opportunities

    USDA-ARS?s Scientific Manuscript database

    Soil health is a broad concept that emphasizes the ecological importance of soils, including sustained plant and animal productivity, human health, and environmental quality. In the United States, soil degradation and associated water quality problems have been widely documented. Improvement and mai...

  9. SPIDERS IN DECOMPOSITION FOOD WEBS OF AGROECOSYSTEMS: THEORY AND EVIDENCE. (R826099)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  10. Resiliency in forage and grazinglands

    USDA-ARS?s Scientific Manuscript database

    This manuscript is a combined effort of the speakers at the 2017 C6 Forage and Grazinglands Division Symposia which was titled “Resiliency in Forage and Grazinglands.” Developing more resilient agroecosystems, including those that produce forage and livestock, will become necessary to maintain agric...

  11. A conceptual model of agroecosystem function as a basis for synthesis

    USDA-ARS?s Scientific Manuscript database

    A primary challenge for LTAR is to organize information about sustainable agricultural intensification such that it can be synthesized across multiple research programs addressing disparate problems. Such synthesis facilitates not only regional to national-scale generalizations to inform the public ...

  12. Distinct soil bacterial communities revealed under a diversely managed agroecosystem

    USDA-ARS?s Scientific Manuscript database

    Land-use change and management are normally enacted to manipulate environments to improve conditions that relate to production, remediation, and accommodation. However, soil microbial community complexity after manipulations is still difficult to quantify. In this study, replicate soil samples we...

  13. Pollen resources for pollinators in specialty oilseed crops

    USDA-ARS?s Scientific Manuscript database

    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...

  14. Linking Soil Microbial Ecology to Ecosystem Functioning in Integrated Crop-Livestock Systems

    USDA-ARS?s Scientific Manuscript database

    Enhanced soil stability, nutrient cycling and C sequestration potential are important ecosystem functions driven by soil microbial processes and are directly influenced by agricultural management. Integrated crop-livestock agroecosystems (ICL) can enhance these functions via high-residue returning c...

  15. Hydrologic budgets across the Long-Term Agroecosystems Research network

    USDA-ARS?s Scientific Manuscript database

    Quantification of the components of the hydrologic budget at a site (precipitation, evaporation, runoff,…) gives important indications about major and minor hydrologic processes controlling field and watershed scale response. Hydrologic budgets are needed prior to assessment of potential changes att...

  16. Timely precipitation drives cover crop outcomes

    USDA-ARS?s Scientific Manuscript database

    Cover crops can expand ecosystem services, though sound management recommendations for their use within semi-arid cropping systems is currently constrained by a lack of information. This study was conducted to determine agroecosystem responses to late-summer seeded cover crops under no-till managem...

  17. Date palm: Production

    USDA-ARS?s Scientific Manuscript database

    The future of date palm, as a dioecious, monocot fruit tree largely depends on (1) developing advanced knowledge and information about the dynamics, management, and sustainability of the tree as a central component of the oasis agro-ecosystem, and (2) in-depth understanding of the genetic diversity ...

  18. Agroecology: Implications for plant response to climate change

    USDA-ARS?s Scientific Manuscript database

    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 ...

  19. ASSESSING THE SUITABILITY OF WINDBREAKS AS WILDLIFE HABITAT - 1994 PILOT PLAN

    EPA Science Inventory

    The Environmental Monitoring and Assessment Program's (EMAP) Agroecosystem Resource Group is developing a program to monitor and evaluate the ecological condition of United States agricultural lands. indbreaks are an important non-crop element in the Great Plains, an extensive ag...

  20. Morphological plasticity in watermelon in response to interspecific competition in a low-resource intercropping system

    USDA-ARS?s Scientific Manuscript database

    Interspecies specific interactions are generally regarded as drivers of plant productivity in multispecies agroecosystems. Positive interactions such as facilitation can dominate over competition under high abiotic stress conditions. Furthermore, complementary use of resource in diverse communities ...

  1. Impacts of Cover Crops on Water and Nutrient Dynamics in Agroecosystems

    NASA Astrophysics Data System (ADS)

    Williard, K.; Swanberg, S.; Schoonover, J.

    2013-05-01

    Intensive cropping systems of corn (Zea Mays L.) and soybeans (Glycine max) are commonly leaky systems with respect to nitrogen (N). Reactive N outputs from agroecosystems can contribute to eutrophication and hypoxic zones in downstream water bodies and greenhouse gas (N2O) emissions. Incorporating cover crops into temperate agroecosystem rotations has been promoted as a tool to increase nitrogen use efficiency and thus limit reactive N outputs to the environment. Our objective was determine how cereal rye (Secale cereal L.) and annual ryegrass (Lolium multiflorum) cover crops impact nutrient and soil water dynamics in an intensive corn and soybean cropping rotation in central Illinois. Cover crops were planted in mid to late October and terminated in early April prior to corn or soybean planting. In the spring just prior to cover crop termination, soil moisture levels were lower in the cover crop plots compared to no cover plots. This can be a concern for the subsequent crop in relatively dry years, which the Midwestern United States experienced in 2012. No cover plots had greater nutrient leaching below the rooting zone compared to cover crop areas, as expected. The cover crops were likely scavenging nutrients during the fall and early spring and should provide nutrients to the subsequent crop via decomposition and mineralization of the cover crop residue. Over the long term, cover crop systems should produce greater inputs and cycling of carbon and N, increasing the productivity of crops due to the long-term accumulation of soil organic matter. This study demonstrates that there may be short term trade-offs in reduced soil moisture levels that should be considered alongside the long term nutrient scavenging and recycling benefits of cover crops.

  2. Genetic Variability of Stolbur Phytoplasma in Hyalesthes obsoletus (Hemiptera: Cixiidae) and its Main Host Plants in Vineyard Agroecosystems.

    PubMed

    Landi, Lucia; Riolo, Paola; Murolo, Sergio; Romanazzi, Gianfranco; Nardi, Sandro; Isidoro, Nunzio

    2015-08-01

    Bois noir is an economically important grapevine yellows that is induced by 'Candidatus Phytoplasma solani' and principally vectored by the planthopper Hyalesthes obsoletus Signoret (Hemiptera: Cixiidae). This study explores the 'Ca. P. solani' genetic variability associated to the nettle-H. obsoletus and bindweed-H. obsoletus systems in vineyard agroecosystems of the central-eastern Italy. Molecular characterization of 'Ca. P. solani' isolates was carried out using polymerase chain reaction/restriction fragment length polymorphism to investigate the nonribosomal vmp1 gene. Seven phytoplasma vmp-types were detected among the host plants- and insect-associated field-collected samples. The vmp1 gene showed the highest polymorphism in the bindweed-H. obsoletus system, according to restriction fragment length polymorphism analysis, which is in agreement with nucleotide sequence analysis. Five vmp-types were associated with H. obsoletus from bindweed, of which one was solely restricted to planthoppers, with one genotype also in planthoppers from nettle. Type V12 was the most prevalent in both planthoppers and bindweed. H. obsoletus from nettle harbored three vmp-types, of which V3 was predominant. V3 was the only type detected for nettle. Our data demonstrate that planthoppers might have acquired some 'Ca. P. solani' profiles from other plant hosts before landing on nettle or bindweed. Overall, the different vmp1 gene rearrangements observed in these two plant hosts-H. obsoletus systems might represent different adaptations of the pathogen to the two host plants. Molecular information about the complex of vmp-types provides useful data for better understanding of Bois noir epidemiology in vineyard agroecosystem. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Effect of rhizobacterial consortia from undisturbed arid- and agro-ecosystems on wheat growth under different conditions.

    PubMed

    Inostroza, N G; Barra, P J; Wick, L Y; Mora, M L; Jorquera, M A

    2017-02-01

    Plant growth-promoting rhizobacteria (PGPR) are studied as complements/alternatives to chemical fertilizers used in agriculture. However, poor information exists on the potential of PGPR from undisturbed ecosystems. Here, we have evaluated the plant growth-promoting (PGP) effect of rhizobacterial consortia from undisturbed Chilean arid ecosystems (Consortium C1) and agro-ecosystems (Consortium C2) on plant biomass production. The PGP effects of C1 and C2 were assayed in wheat seedlings (Triticum aestivum L.) grown in pots under growth chamber conditions and in pots placed in an open greenhouse under natural conditions, using two different Chilean Andisols (Piedras Negras and Freire series) kept either at 30 or 60% of their maximum water holding capacity (MWHC). PGP effects depended on the soil type, MWHC and the growth conditions tested. Although both consortia showed PGB effects in artificial soils relative to controls in growth chambers, only C1 provoked a PGP effect at 60% MWHC in phosphorus-poor soil of the 'Piedras Negras' series. At natural conditions, however, only C1 exhibited statistically significant PGP effects at 30% MWHC in 'Piedras Negras', yet and most importantly allowed to maintain similar plant biomass as at 60% MWHC. Our results support possible applications of rhizobacterial consortia from arid ecosystems to improve wheat growth in Chilean Andisols under water shortage conditions. Wheat seedling inoculated with rhizobacterial consortia obtained from an undisturbed Chilean arid ecosystem showed improved growth in phosphorus-poor and partly dry soil. Arid ecosystems should be considered in further studies as an alternative source of microbial inoculants for agro-ecosystems subjected to stressful conditions by low nutrients and/or adverse climate events. © 2016 The Society for Applied Microbiology.

  4. Evapotranspiration partitioning for three agro-ecosystems with contrasting moisture conditions: a comparison of an isotope method and a two-source model calculation

    NASA Astrophysics Data System (ADS)

    Wei, Z.; Lee, X.; Wen, X.; Xiao, W.

    2017-12-01

    Quantification of the contribution of transpiration (T) to evapotranspiration (ET) is a requirement for understanding changes in carbon assimilation and water cycling in a changing environment. So far, few studies have examined seasonal variability of T/ET and compared different ET partitioning methods under natural conditions across diverse agro-ecosystems. In this study, we apply a two-source model to partition ET for three agro-ecosystems (rice, wheat and corn). The model-estimated T/ET ranges from 0 to 1, with a near continuous increase over time in the early growing season when leaf area index (LAI) is less than 2.5 and then convergence towards a stable value beyond LAI of 2.5. The seasonal change in T/ET can be described well as a function of LAI, implying that LAI is a first-order factor affecting ET partitioning. The two-source model results show that the growing-season (May - September for rice, April - June for wheat and June to September for corn) T/ET is 0.50, 0.84 and 0.64, while an isotopic approach shows that T/ET is 0.74, 0.93 and 0.81 for rice, wheat and maize, respectively. The two-source model results are supported by soil lysimeter and eddy covariance measurements made during the same time period for wheat (0.87). Uncertainty analysis suggests that further improvements to the Craig-Gordon model prediction of the evaporation isotope composition and to measurement of the isotopic composition of ET are necessary to achieve accurate flux partitioning at the ecosystem scale using water isotopes as tracers.

  5. Health status of tadpoles and metamorphs of Rhinella arenarum (Anura, Bufonidae) that inhabit agroecosystems and its implications for land use.

    PubMed

    Babini, María Selene; Bionda, Clarisa de Lourdes; Salas, Nancy Edith; Martino, Adolfo Ludovico

    2015-08-01

    Perturbations of water bodies near agricultural and livestock systems can affect embryonic and larval stages of anurans and negatively impact adult populations and structure of amphibian communities. This study is focused on early development of Rhinella arenarum, for which body growth, abnormalities in the oral disc and genetic damage on erythrocytes were analyzed to establish the impact of agroecosystems on local populations of amphibians. Tadpoles and metamorphs of R. arenarum were collected in three agroecosystems (namely, C1, C2, and C3) and in a site without agricultural and livestock activities (SM) from central Argentina. Egg masses of C1 were extracted for breeding tadpoles under laboratory conditions (Lab). Tadpoles were in small size and lighter in weight in C1 and C2. Metamorphs were shorter and lighter in weight in C1 and C3. In SM and Lab samples, no tadpoles with abnormal LTRF (labial tooth row formula) or without labial teeth were observed. In C1, the highest frequency of abnormal LTRF was recorded and was the only site in which tadpoles without labial teeth were found. In C1 and C2 the tadpoles had highest micronucleus frequencies and nuclear abnormalities. C1 can be considered as the site with the highest anthropogenic perturbation and with less healthy tadpoles. Livestock practices such as alternating cattle between parcel and keeping a buffer between crops and water bodies, would allow a better development of the first aquatic stages that are essential for the conservation of the anuran populations. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. A Keystone Ant Species Provides Robust Biological Control of the Coffee Berry Borer Under Varying Pest Densities.

    PubMed

    Morris, Jonathan R; Vandermeer, John; Perfecto, Ivette

    2015-01-01

    Species' functional traits are an important part of the ecological complexity that determines the provisioning of ecosystem services. In biological pest control, predator response to pest density variation is a dynamic trait that impacts the provision of this service in agroecosystems. When pest populations fluctuate, farmers relying on biocontrol services need to know how natural enemies respond to these changes. Here we test the effect of variation in coffee berry borer (CBB) density on the biocontrol efficiency of a keystone ant species (Azteca sericeasur) in a coffee agroecosystem. We performed exclosure experiments to measure the infestation rate of CBB released on coffee branches in the presence and absence of ants at four different CBB density levels. We measured infestation rate as the number of CBB bored into fruits after 24 hours, quantified biocontrol efficiency (BCE) as the proportion of infesting CBB removed by ants, and estimated functional response from ant attack rates, measured as the difference in CBB infestation between branches. Infestation rates of CBB on branches with ants were significantly lower (71%-82%) than on those without ants across all density levels. Additionally, biocontrol efficiency was generally high and did not significantly vary across pest density treatments. Furthermore, ant attack rates increased linearly with increasing CBB density, suggesting a Type I functional response. These results demonstrate that ants can provide robust biological control of CBB, despite variation in pest density, and that the response of predators to pest density variation is an important factor in the provision of biocontrol services. Considering how natural enemies respond to changes in pest densities will allow for more accurate biocontrol predictions and better-informed management of this ecosystem service in agroecosystems.

  7. Problems Inherent to Augmentation of Natural Enemies in Open Agriculture.

    PubMed

    Michaud, J P

    2018-04-01

    Augmentation biological control has successfully replaced a lot of insecticide use in 'closed system' agriculture (e.g., greenhouses). The profitable commercialization of biocontrol agents in greenhouses has created an incentive to expand markets for mass-reared beneficial insects into open agricultural systems, often without sufficient scientific justification. However, the semi-contained nature of greenhouse culture is often critical to the success of augmentation and can serve to mask potential pitfalls and intrinsic limitations of this approach in open systems. Factors contributing to greenhouse successes include the reduced biological diversity of contained agroecosystems, the prevention of agent dispersal, the ability to maintain environmental conditions within a range favorable for the agent, the exclusion of competitors and natural enemies of the agent that might otherwise diminish its efficacy, and the absence of alternative prey/hosts that could divert predation/parasitism from the target pest. There are also problems arising from collection of source material from locally adapted populations, and the inadvertent imposition of artificial selection in the course of laboratory rearing. Besides highlighting these pitfalls, this paper aims to encourage more consideration of conservation approaches prior to investment in augmentation programs which entice farmers into perpetual cycles of 'rear and release.' I argue that although augmentation can benefit agriculture whenever it replaces pesticide applications, it does not constitute an ecologically sustainable solution because it requires continued inputs, and it can distract research attention away from more sustainable objectives. Sustainable biological control is best achieved through modifications to cultural practices that increasingly 'naturalize' agroecosystems, thus facilitating the natural recruitment and persistence of beneficial arthropod fauna, combined with habitat management geared to increasing overall plant and arthropod diversity in the agroecosystem.

  8. A Keystone Ant Species Provides Robust Biological Control of the Coffee Berry Borer Under Varying Pest Densities

    PubMed Central

    Morris, Jonathan R.; Vandermeer, John; Perfecto, Ivette

    2015-01-01

    Species’ functional traits are an important part of the ecological complexity that determines the provisioning of ecosystem services. In biological pest control, predator response to pest density variation is a dynamic trait that impacts the provision of this service in agroecosystems. When pest populations fluctuate, farmers relying on biocontrol services need to know how natural enemies respond to these changes. Here we test the effect of variation in coffee berry borer (CBB) density on the biocontrol efficiency of a keystone ant species (Azteca sericeasur) in a coffee agroecosystem. We performed exclosure experiments to measure the infestation rate of CBB released on coffee branches in the presence and absence of ants at four different CBB density levels. We measured infestation rate as the number of CBB bored into fruits after 24 hours, quantified biocontrol efficiency (BCE) as the proportion of infesting CBB removed by ants, and estimated functional response from ant attack rates, measured as the difference in CBB infestation between branches. Infestation rates of CBB on branches with ants were significantly lower (71%-82%) than on those without ants across all density levels. Additionally, biocontrol efficiency was generally high and did not significantly vary across pest density treatments. Furthermore, ant attack rates increased linearly with increasing CBB density, suggesting a Type I functional response. These results demonstrate that ants can provide robust biological control of CBB, despite variation in pest density, and that the response of predators to pest density variation is an important factor in the provision of biocontrol services. Considering how natural enemies respond to changes in pest densities will allow for more accurate biocontrol predictions and better-informed management of this ecosystem service in agroecosystems. PMID:26562676

  9. Understanding soil erosion impacts in temperate agroecosystems: bridging the gap between geomorphology and soil ecology

    NASA Astrophysics Data System (ADS)

    Baxter, C.; Rowan, J. S.; McKenzie, B. M.; Neilson, R.

    2013-04-01

    Soil is a key asset of natural capital, providing a myriad of goods and ecosystem services that sustain life through regulating, supporting and provisioning roles, delivered by chemical, physical and biological processes. One of the greatest threats to soil is accelerated erosion, which raises a natural process to unsustainable levels, and has downstream consequences (e.g. economic, environmental and social). Global intensification of agroecosystems is a major cause of soil erosion which, in light of predicted population growth and increased demand for food security, will continue or increase. Elevated erosion and transport is common in agroecosystems and presents a multi-disciplinary problem with direct physical impacts (e.g. soil loss), other less tangible impacts (e.g. loss of ecosystem productivity), and indirect downstream effects that necessitate an integrated approach to effectively address the problem. Climate is also likely to increase susceptibility of soil to erosion. Beyond physical response, the consequences of erosion on soil biota have hitherto been ignored, yet biota play a fundamental role in ecosystem service provision. To our knowledge few studies have addressed the gap between erosion and consequent impacts on soil biota. Transport and redistribution of soil biota by erosion is poorly understood, as is the concomitant impact on biodiversity and ability of soil to deliver the necessary range of ecosystem services to maintain function. To investigate impacts of erosion on soil biota a two-fold research approach is suggested. Physical processes involved in redistribution should be characterised and rates of transport and redistribution quantified. Similarly, cumulative and long-term impacts of biota erosion should be considered. Understanding these fundamental aspects will provide a basis upon which mitigation strategies can be considered.

  10. Agroecosystems shape population genetic structure of the greenhouse whitefly in Northern and Southern Europe

    PubMed Central

    2014-01-01

    Background To predict further invasions of pests it is important to understand what factors contribute to the genetic structure of their populations. Cosmopolitan pest species are ideal for studying how different agroecosystems affect population genetic structure within a species at different climatic extremes. We undertook the first population genetic study of the greenhouse whitefly (Trialeurodes vaporariorum), a cosmopolitan invasive herbivore, and examined the genetic structure of this species in Northern and Southern Europe. In Finland, cold temperatures limit whiteflies to greenhouses and prevent them from overwintering in nature, and in Greece, milder temperatures allow whiteflies to inhabit both fields and greenhouses year round, providing a greater potential for connectivity among populations. Using nine microsatellite markers, we genotyped 1274 T. vaporariorum females collected from 18 greenhouses in Finland and eight greenhouses as well as eight fields in Greece. Results Populations from Finland were less diverse than those from Greece, suggesting that Greek populations are larger and subjected to fewer bottlenecks. Moreover, there was significant population genetic structure in both countries that was explained by different factors. Habitat (field vs. greenhouse) together with longitude explained genetic structure in Greece, whereas in Finland, genetic structure was explained by host plant species. Furthermore, there was no temporal genetic structure among populations in Finland, suggesting that year-round populations are able to persist in greenhouses. Conclusions Taken together our results show that greenhouse agroecosystems can limit gene flow among populations in both climate zones. Fragmented populations in greenhouses could allow for efficient pest management. However, pest persistence in both climate zones, coupled with increasing opportunities for naturalization in temperate latitudes due to climate change, highlight challenges for the management of cosmopolitan pests in Northern and Southern Europe. PMID:25266268

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

    NASA Astrophysics Data System (ADS)

    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.

  12. The impacts of irrigation with transferred and saline reclaimed water in the soil biological quality of two citrus species: Adaptations to low water availability

    NASA Astrophysics Data System (ADS)

    Bastida, Felipe; Abadía, Joaquín; García, Carlos; Torres, Irene; Ruiz Navarro, Antonio; José Alarcón, Juan; Nicolás, Emilio

    2017-04-01

    Mediterranean agroecosystems are limited by the availability of water and hence it is fundamental to find new water sources for sustainable agriculture in the face of climate change. Here, the effects of irrigation with water from different sources were analyzed in the soil microbial community and plant status of grapefruit and mandarin trees in a Mediterranean agro-ecosystem located in south-east of Spain. Four irrigation treatments were evaluated: i) water with an average electrical conductivity (EC) of 1.1 dS m-1 from the "Tagus-Segura" water-transfer canal (TW); ii) reclaimed water (EC = 3.21 dS m-1) from a wastewater-treatment-plant (RW); iii) irrigation with TW, except in the second stage of fruit development, when RW was applied (TWc); and iv) irrigation with RW except in the second stage, when TW was used (RWc). Phospholipid fatty acids indicated that microbial biomass was greater under grapefruit than under mandarin. In the case of grapefruit, TW showed a lower bacterial biomass than RW, RWc, and TWc, while RW showed the lowest values in the mandarin soil. In grapefruit soil, β-glucosidase and cellobiohydrolase activities, related to C cycling, were greater in RW and TWc than in TW and RWc. In mandarin soil, the greatest activity of these enzymes was found in TWc. The saline stress induced lower net photosynthesis (A) and stomatal conductance (gs) in plants of RW, RWc and TWc in comparison with TW. The annual use of reclaimed water or the combined irrigation with TWc positively influenced the soil biological quality of a grapefruit agro-ecosystem. Conversely, the mandarin soil community was more sensitive to the annual irrigation with RW.

  13. Call of the wild rice: Oryza rufipogon shapes weedy rice evolution in Southeast Asia

    USDA-ARS?s Scientific Manuscript database

    Agricultural weeds serve as models for studying the genetic basis of rapid adaptation, with weed-adaptive traits potentially evolving independently in geographically distinct but environmentally similar agroecosystems. Weedy relatives of domesticated crops can be especially interesting systems becau...

  14. New approaches to understanding weed seed predation in agroecosystems

    USDA-ARS?s Scientific Manuscript database

    Postdispersal predation of weed seeds in arable systems can be a valuable ecosystem service, with the potential to support ecological approaches to weed management by reducing inputs to the soil seed bank. Scientific understanding of factors regulating weed seed predation rates is still insufficient...

  15. Dynamics of soil microbial communities in agroecosystems managed for biofuel production

    USDA-ARS?s Scientific Manuscript database

    Elevated atmospheric CO2 concentrations and their link to global climate change are stimulating efforts to reduce dependence on fossil fuels and increase use of alternative energy sources. Initial efforts to incorporate significant amounts of cellulosic ethanol into transportation fuels are focused ...

  16. Sorption of lincomycin by manure-derived biochars from water

    USDA-ARS?s Scientific Manuscript database

    The presence of antibiotics in agroecosystems raises serious concerns about the proliferation of antibiotic resistant bacteria and potential adverse effects to human health. Soil amendment with biochars pyrolyzed from manures may be a win-win strategy for novel manure management and antibiotics abat...

  17. Industrial oilseeds bolster "hub" crop yields when used in rotation

    USDA-ARS?s Scientific Manuscript database

    Lack of agroecosystem diversity across the U.S. agricultural landscape is linked to several environmental issues associated with air, water, and soil quality and biodiversity. Several new industrial oilseed crops with commercial potential, offer farmers new economic opportunities and a portfolio of ...

  18. Phylogenetic diversity of Brazilian Metarhizium associated with sugarcane agriculture

    USDA-ARS?s Scientific Manuscript database

    Biological control of spittlebug with Metarhizium in sugarcane is an example of the successful application of sustainable pest management in Brazil. However little is known about the richness, distribution and ecology of Metarhizium species in the agroecosystems and natural environments of Brazil. W...

  19. Mobilizing the rhizosphere microbiome to enhance orchard system resilience

    USDA-ARS?s Scientific Manuscript database

    Soils possess a wealth of biological resources that can be harnessed for use in the optimization of plant performance in agroecosystems. Functional biological control outcomes, beyond those realized based upon introduction of synthetic microbiomes, have been documented in a variety of instances, an...

  20. Evaluating strategies for sustainable intensification of U.S. agriculture through the Long-Term Agroecosystem Research network

    USDA-ARS?s Scientific Manuscript database

    Sustainable intensification is an emerging model for agriculture designed to reconcile accelerating global demand for agricultural products with long-term environmental stewardship. Defined here as increasing agricultural production while maintaining or improving environmental quality, sustainable i...

  1. Enhancing resource availability in agro-ecosystems for beneficial arthropods through floral provisioning

    USDA-ARS?s Scientific Manuscript database

    There has been a decline in beneficial arthropods (insects and spiders) including pollinators because of habitat destruction and intense management practices. Enhancing landscapes with additional floral and other non-crop habitats has the potential to attract pollinators, and predatory arthropods wh...

  2. Trophic interactions in contrating production systems: MiSeq versus multiplex PCR

    USDA-ARS?s Scientific Manuscript database

    Maintaining biodiversity is an important aspect of long-term agricultural sustainability. Generalist predators such as spiders and insect predators often prey upon common pest species, making them a beneficial component of agroecosystems. Much research has been devoted to understanding the roles of ...

  3. Trophic interactions in contrasting production systems: MiSeq versus multiplex PCR

    USDA-ARS?s Scientific Manuscript database

    Maintaining biodiversity is an important aspect of long-term agricultural sustainability. Generalist predators such as spiders and insect predators oftern prey upon common species, making them a beneficial component of agroecosystems. Much research has been devoted to understanding the roles of ge...

  4. Relative susceptibility of pecan germplasm to blackmargined aphid

    USDA-ARS?s Scientific Manuscript database

    The blackmargined aphid, Monellia caryella (Fitch), is an important phytophage in the pecan, Carya illinoinensis (Wangenh.) K. Koch, agroecosystem where it often is treated with insecticide. Pecan cultivars released by the USDA Pecan Breeding Program vary in susceptibility and risk of damage from t...

  5. How Universal Is the Relationship Between Remotely Sensed Vegetation Indices (VI) and Crop Leaf Area Index (LAI)?

    NASA Technical Reports Server (NTRS)

    Kang, Yanghui; Ozdogan, Mutlu; Zipper, Samuel C.; Roman, Miguel

    2016-01-01

    Global LAI-VI relationships are statistically significant, crop-specific, and mostly non-linear. This research enables the operationalization of large-area crop modeling and, by extension, has relevance to both fundamental and applied agroecosystem research.

  6. Understanding the Variability in Soybean Nitrogen Fixation across Agroecosystems

    USDA-ARS?s Scientific Manuscript database

    Conventional farming practices have uncoupled carbon (C) and nitrogen (N) cycles through the application of inorganic N fertilizers applied in plant available forms at levels that saturate the system. As a result, extensive N losses via leaching and denitrification are having significant environment...

  7. Assessing coastal plain risk indices for subsurface phosphorus loss

    USDA-ARS?s Scientific Manuscript database

    Phosphorus (P) Indices are important tools for nutrient management planning in the U.S. whose evaluation often has been deemphasized in favor of research and development. Assessing P Indices in artificially drained agroecosystems is especially important, as subsurface flow is the predominant mode of...

  8. Antibiotic effects on microbial community characteristics in soils under conservation management practices

    USDA-ARS?s Scientific Manuscript database

    Veterinary antibiotics (VAs) administered to livestock are introduced to agroecosystems via land application of manure, posing a potential human and environmental health risk. These Antibiotics may adversely affect soil microbial communities. The objectives of this research were to investigate poten...

  9. Nanoscale interactions between engineered nanomaterials and black carbon (Biochar) in soil

    USDA-ARS?s Scientific Manuscript database

    Engineered nanomaterials (NMs) enter agricultural soils directly as additives in agrichemical formulations1 and indirectly as contaminants in municipal sewage sludge.2 NIFA has a vested interest in developing predictive models for the fate and nanotoxicity of NMs in agroecosystems. An understanding ...

  10. Exclusion of agricultural lands in spatial conservation prioritization strategies: consequences for biodiversity and ecosystem service representation

    PubMed Central

    Durán, América P.; Duffy, James P.; Gaston, Kevin J.

    2014-01-01

    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. PMID:25143040

  11. A Metabarcoding Survey on the Fungal Microbiota Associated to the Olive Fruit Fly.

    PubMed

    Malacrinò, Antonino; Schena, Leonardo; Campolo, Orlando; Laudani, Francesca; Mosca, Saveria; Giunti, Giulia; Strano, Cinzia Patricia; Palmeri, Vincenzo

    2017-04-01

    The occurrence of interaction between insects and fungi is interesting from an ecological point of view, particularly when these interactions involve insect pests and plant pathogens within an agroecosystem. In this study, we aimed to perform an accurate analysis on the fungal microbiota associated to Bactrocera oleae (Rossi) through a metabarcoding approach based on 454 pyrosequencing. From this analysis, we retrieved 43,549 reads that clustered into 128 operational taxonomic units (OTUs), of which 29 resulted in the "core" associate fungi of B. oleae. This fungal community was mainly represented by sooty mould fungi, such as Cladosporium spp., Alternaria spp. and Aureobasidium spp., by plant pathogens like Colletotrichum spp. and Pseudocercospora spp., along with several other less abundant taxa whose ecology is unclear in most of the cases. Our findings lead to new insights into the microbial ecology of this specific ecological niche, enabling the understanding of a complex network of interactions within the olive agroecosystem.

  12. Physico-chemical protection, rather than biochemical composition, governs the responses of soil organic carbon decomposition to nitrogen addition in a temperate agroecosystem.

    PubMed

    Tan, Wenbing; Wang, Guoan; Huang, Caihong; Gao, Rutai; Xi, Beidou; Zhu, Biao

    2017-11-15

    The heterogeneous responses of soil organic carbon (SOC) decomposition in different soil fractions to nitrogen (N) addition remain elusive. In this study, turnover rates of SOC in different aggregate fractions were quantified based on changes in δ 13 C following the conversion of C 3 to C 4 vegetation in a temperate agroecosystem. The turnover of both total organic matter and specific organic compound classes within each aggregate fraction was inhibited by N addition. Moreover, the intensity of inhibition increases with decreasing aggregate size and increasing N addition level, but does not vary among chemical compound classes within each aggregate fraction. Overall, the response of SOC decomposition to N addition is dependent on the physico-chemical protection of SOC by aggregates and minerals, rather than the biochemical composition of organic substrates. The results of this study could help to understand the fate of SOC in the context of increasing N deposition. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. The impact of genetically modified crops on soil microbial communities.

    PubMed

    Giovannetti, Manuela; Sbrana, Cristiana; Turrini, Alessandra

    2005-01-01

    Genetically modified (GM) plants represent a potential benefit for environmentally friendly agriculture and human health. Though, poor knowledge is available on potential hazards posed by unintended modifications occurring during genetic manipulation. The increasing amount of reports on ecological risks and benefits of GM plants stresses the need for experimental works aimed at evaluating the impact of GM crops on natural and agro-ecosystems. Major environmental risks associated with GM crops include their potential impact on non-target soil microorganisms playing a fundamental role in crop residues degradation and in biogeochemical cycles. Recent works assessed the effects of GM crops on soil microbial communities on the basis of case-by-case studies, using multimodal experimental approaches involving different target and non-target organisms. Experimental evidences discussed in this review confirm that a precautionary approach should be adopted, by taking into account the risks associated with the unpredictability of transformation events, of their pleiotropic effects and of the fate of transgenes in natural and agro-ecosystems, weighing benefits against costs.

  14. Evapotranspiration Cycles in a High Latitude Agroecosystem: Potential Warming Role

    PubMed Central

    Ruairuen, Watcharee

    2015-01-01

    As the acreages of agricultural lands increase, changes in surface energetics and evapotranspiration (ET) rates may arise consequently affecting regional climate regimes. The objective of this study was to evaluate summertime ET dynamics and surface energy processes in a subarctic agricultural farm in Interior Alaska. The study includes micrometeorological and hydrological data. Results covering the period from June to September 2012 and 2013 indicated consistent energy fractions: LE/R net (67%), G/R net (6%), H/R net (27%) where LE is latent heat flux, R net is the surface net radiation, G is ground heat flux and H is the sensible heat flux. Additionally actual surface evapotranspiration from potential evaporation was found to be in the range of 59 to 66%. After comparing these rates with those of most prominent high latitude ecosystems it is argued here that if agroecosystem in high latitudes become an emerging feature in the land-use, the regional surface energy balance will significantly shift in comparison to existing Arctic natural ecosystems. PMID:26368123

  15. Evapotranspiration Cycles in a High Latitude Agroecosystem: Potential Warming Role.

    PubMed

    Ruairuen, Watcharee; Fochesatto, Gilberto J; Sparrow, Elena B; Schnabel, William; Zhang, Mingchu; Kim, Yongwon

    2015-01-01

    As the acreages of agricultural lands increase, changes in surface energetics and evapotranspiration (ET) rates may arise consequently affecting regional climate regimes. The objective of this study was to evaluate summertime ET dynamics and surface energy processes in a subarctic agricultural farm in Interior Alaska. The study includes micrometeorological and hydrological data. Results covering the period from June to September 2012 and 2013 indicated consistent energy fractions: LE/Rnet (67%), G/Rnet (6%), H/Rnet (27%) where LE is latent heat flux, Rnet is the surface net radiation, G is ground heat flux and H is the sensible heat flux. Additionally actual surface evapotranspiration from potential evaporation was found to be in the range of 59 to 66%. After comparing these rates with those of most prominent high latitude ecosystems it is argued here that if agroecosystem in high latitudes become an emerging feature in the land-use, the regional surface energy balance will significantly shift in comparison to existing Arctic natural ecosystems.

  16. Soil carbon and nitrogen losses following deforestation in Ethiopia

    USDA-ARS?s Scientific Manuscript database

    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...

  17. Nectar production in oilseeds: Food for pollinators in an agriculture dominated landscape

    USDA-ARS?s Scientific Manuscript database

    Simplified agroecosystems have degraded 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...

  18. Big agronomic data validates an oxymoron: Sustainable intensification under climate change

    USDA-ARS?s Scientific Manuscript database

    Crop science is increasingly embracing big data to reconcile the apparent rift between intensification of food production and sustainability of a steadily stressed production base. A strategy based on long-term agroecosystem research and modeling simulation of crops, crop rotations and cropping sys...

  19. Crop response to climate: ecophysical models

    USDA-ARS?s Scientific Manuscript database

    Ecophysiological models were the dominant tools used to estimate the potential impact of climate change in agroecosystems in the Third and Fourth Assessment Reports of the IPCC and are widely used elsewhere in climate change research. These models, also known as “crop models” or “simulation models”,...

  20. Big Data Initiatives for Agroecosystems

    USDA-ARS?s Scientific Manuscript database

    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...

  1. Spatio-temporal variation in Helicoverpa egg parasitism by Trichogramma in a tropical Bt-transgenic cotton landscape

    USDA-ARS?s Scientific Manuscript database

    Understanding the spatio-temporal dynamics of insects in agroecosystems is crucial when developing effective management strategies that emphasise biological control of pests. Wild populations of Trichogramma Westwood egg parasitoids are utilised for biological suppression of the potentially resistan...

  2. Integrated modeling of pesticide risks to breeding birds in North American agroecosystems

    EPA Science Inventory

    Pesticide usage in the United States is ubiquitous in urban, suburban, and rural environments. Scientists at the United States Environmental Protection Agency (USEPA) assess the fate of pesticides and the risk those pesticides pose to the environment and non-target wildlife. We p...

  3. Identifying agro-ecoregions for the Long Term Agroecosystem Research (LTAR) network

    USDA-ARS?s Scientific Manuscript database

    The LTAR network exists to examine questions of agricultural sustainability in working lands across the continental US. To effectively address agricultural sustainability at this scale, experimental designs must be placed into the context of a regional framework that can extrapolate site-specific re...

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

    EPA Science Inventory

    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...

  5. Criteria for Space-Based Sensor Applied to Bt Crop Monitoring

    EPA Science Inventory

    A joint agro-ecosystem research effort of NASA and USEPA has focused on the development of a decision support system designed to predict the development of insect pest resistance to transgenic toxins in maize. The use of NASA-developed remote sensing technologies that significant...

  6. Precision control of soil N cycling via soil functional zone management

    USDA-ARS?s Scientific Manuscript database

    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 (...

  7. Soil quality indicator responses to row crop, grazed pasture, and agroforestry buffer management

    USDA-ARS?s Scientific Manuscript database

    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. ...

  8. Identification of an atrazine-degrading benzoxazinoid in Eastern gamagrass (tripsacum dactyloides)

    USDA-ARS?s Scientific Manuscript database

    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...

  9. Net global warming potential and greenhouse gas intensity

    USDA-ARS?s Scientific Manuscript database

    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...

  10. Uncertainty of water budget closure across the Long-Term Agroecosystems Research network

    USDA-ARS?s Scientific Manuscript database

    Quantification of the various components of the hydrologic budget at a site (precipitation, evaporation, runoff,…) gives important indications about major and minor hydrologic processes controlling field and watershed scale response. The objectives of this study were to: 1) develop hydrologic budget...

  11. Fruit metabolite networks in engineered and non-engineered tomato genotypes reveal fluidity in a hormone and agroecosystem specific manner.

    PubMed

    Fatima, Tahira; Sobolev, Anatoly P; Teasdale, John R; Kramer, Matthew; Bunce, Jim; Handa, Avtar K; Mattoo, Autar K

    Metabolomics provides a view of endogenous metabolic patterns not only during plant growth, development and senescence but also in response to genetic events, environment and disease. The effects of the field environment on plant hormone-specific metabolite profiles are largely unknown. Few studies have analyzed useful phenotypes generated by introducing single or multiple gene events alongside the non-engineered wild type control at field scale to determine the robustness of the genetic trait and its modulation in the metabolome as a function of specific agroecosystem environments. We evaluated the influence of genetic background (high polyamine lines; low methyl jasmonate line; low ethylene line; and isogenic genotypes carrying double transgenic events) and environments (hairy vetch, rye, plastic black mulch and bare soil mulching systems) on the metabolomic profile of isogenic reverse genetic mutations and selected mulch based cropping systems in tomato fruit. Net photosynthesis and fruit yield were also determined. NMR spectroscopy was used for quantifying metabolites that are central to primary metabolism. We analyzed both the first moment (means) of metabolic response to genotypes and agroecosystems by traditional univariate/multivariate methods, and the second moment (covariances) of responses by creating networks that depicted changes in correlations of paired metabolites. This particular approach is novel and was necessary because our experimental material yielded highly variable metabolic responses that could not be easily understood using the traditional analytical approaches for first moment statistics. High endogenous spermidine and spermine content exhibited strong effects on amino acids, Krebs cycle intermediates and energy molecules (ADP + ATP) in ripening fruits of plants grown under different agroecosystem environments. The metabolic response to high polyamine genotypes was similar to the response to hairy vetch cover crop mulch; supported by the pattern of changes in correlation between metabolites. Changes in primary metabolites of genotypes mutated for the deficiency of ethylene or methyl jasmonate were unique under all growth conditions and opposite of high polyamine genotype results. The high polyamine trait was found to dominate the low ethylene and low jasmonate mutations under field conditions. For several metabolites low ethylene and low methyl jasmonate genotypes had an inverse relationship. Collectively, these results affirm that interactions between metabolite pathways and growth environments are affected by genotype, and influence the metabolite quality of a crop. This study portrays how metabolite relationships change, both in mean and in correlation, under different genotypic and environmental conditions. Although these networks are surprisingly dynamic, we also find examples of selectively conserved associations.

  12. CO2 Fluxes Monitoring at the Level of Field Agroecosystem in Moscow Region of Russia

    NASA Astrophysics Data System (ADS)

    Meshalkina, Joulia; Mazirov, Ilya; Samardzic, Miljan; Yaroslavtsev, Alexis; Valentini, Riccardo; Vasenev, Ivan

    2014-05-01

    The Central Russia is still one of the less GHG-investigated European areas especially in case of agroecosystem-level carbon dioxide fluxes monitoring by eddy covariance method. The eddy covariance technique is a statistical method to measure and calculate vertical turbulent fluxes within atmospheric boundary layers. The major assumption of the metod is that measurements at a point can represent an entire upwind area. Eddy covariance researches, which could be considered as repeated for the same area, are very rare. The research has been carried out on the Precision Farming Experimental Field of the Russian Timiryazev State Agricultural University (Moscow, Russia) in 2013 under the support of RF Government grant No. 11.G34.31.0079. Arable derno-podzoluvisls have around 1 The results have shown high daily and seasonal dynamic of agroecosystem CO2 emission. Sowing activates soil microbiological activity and the average soil CO2 emission and adsorption are rising at the same time. CO2 streams are intensified after crop emerging from values of 3 to 7 μmol/s-m2 for emission, and from values of 5 to 20 μmol/s-m2 for adsorption. Stabilization of the flow has come at achieving plants height of 10-12 cm. The vegetation period is characterized by high average soil CO2 emission and adsorption at the same time, but the adsorption is significantly higher. The resulted CO2 absorption during the day is approximately 2-5 times higher than emissions at night. For example, in mid-June, the absorption value was about 0.45 mol/m2 during the day-time, and the emission value was about 0.1 mol/m2 at night. After harvesting CO2 emission is becoming essentially higher than adsorption. Autumn and winter data are fluctuate around zero, but for some periods a small predominance of CO2 emissions over the absorption may be observed. The daily dynamics of CO2 emissions depends on the air temperature with the correlation coefficient changes between 0.4 and 0.8. Crop stage, agrotechnological operation and soil moisture has stronger influence on the seasonal dynamics of soil and agroecosystem CO2 emissions. Obtained unique for Russian agriculture data are very useful for land-use practices environmental assessment, for soil organic carbon dynamics analysis and agroecological evaluation, and for food C-footprint calculation. Their system analysis together with the nearest forest eddy covariance stations helps us to understand better the land-use change impact on the GHG fluxes dynamics and ecosystem services.

  13. Climate change impacts on yields and soil carbon in dryland agriculture

    USDA-ARS?s Scientific Manuscript database

    Dryland agroecosystems could be a sizable sink for atmospheric carbon (C) due to their spatial extent and level of degradation, providing climate change mitigation. We examined productivity and soil C dynamics under two IPCC climate change scenarios (RCP 4.5; RCP 8.5), utilizing long-term experiment...

  14. Unified Plant Growth Model (UPGM). 1. Background, objectives, and vision.

    USDA-ARS?s Scientific Manuscript database

    Since the development of the Environmental Policy Integrated Climate (EPIC) model in 1988, the EPIC-based plant growth code has been incorporated and modified into many agro-ecosystem models. The goals of the Unified Plant Growth Model (UPGM) project are: 1) integrating into one platform the enhance...

  15. Barcode haplotype variation in North American agroecosystem ladybird beetles (Coleoptera: Coccinellidae

    USDA-ARS?s Scientific Manuscript database

    DNA barcodes have proven invaluable in identifying and distinguishing insect pests, for example for determining the provenance of exotic invasives, but relatively few insect natural enemies have been barcoded. We used Folmer et al.’s universal invertebrate primers (1994), and those designed by Heber...

  16. Rye cover crop effects on soil properties in no-till corn silage/soybean agroecosystems

    USDA-ARS?s Scientific Manuscript database

    Farmers in the U.S. Corn Belt are showing increasing interest in winter cover crops. Known benefits of winter cover crops include reductions in nutrient leaching, erosion mitigation, and weed suppression, however little research has investigated the effects of winter cover crops on soil properties. ...

  17. Impact of changing land-use and hydrology on soil organic carbon dynamics in beef cattle agroecosystem

    USDA-ARS?s Scientific Manuscript database

    Basic information on the ecological understanding and the responses of systems to water regime change is essential for maintaining ecosystems environmental integrity and productivity. Flooding of formerly drained areas is common practice in wetland restoration. Such practice could profoundly affect ...

  18. The unique genomic landscape surrounding the EPSPS gene in glyphosate resistant Amaranthus palmeri: A repetitive path to resistance

    USDA-ARS?s Scientific Manuscript database

    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...

  19. Soil aggregation and glomalin in a soil quality management study in a cold, semi-arid region

    USDA-ARS?s Scientific Manuscript database

    Global food insecurity and rapidly diminishing water, soil, and energy resources are putting pressure on agroecosystems to efficiently produce more food while maintaining or enhancing soil quality, particularly soil aggregation. A field study established in 1993 near Mandan, ND sought to evaluate im...

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

    EPA Science Inventory

    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...

  1. Understanding the scale and drivers of ecosystem services in working landscapes of the southeastern US

    USDA-ARS?s Scientific Manuscript database

    The USDA Long Term Agroecosystem Research (LTAR) network exists to build knowledge required for “sustainable intensification of agriculture, increasing yields from the current agricultural land base while minimizing or reversing agriculture’s adverse environmental impacts.” Of the 18 current LTAR lo...

  2. A Simple Relationship Between Short- and Long-term Seed Predation Rates

    USDA-ARS?s Scientific Manuscript database

    Weed seed predation is an important ecosystem service supporting weed management in low-external-input agroecosystems. For convenience, measurements of seed predation are often made at very short time scales (< 3 d). However, one of the primary uses of such data, the parameterization of models of cr...

  3. Development of the Land-use and Agricultural Management Practice web-Service (LAMPS) for generating crop rotations in space and time

    USDA-ARS?s Scientific Manuscript database

    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...

  4. Behavioral Changes Based on a Course in Agroecology: A Mixed Methods Study

    ERIC Educational Resources Information Center

    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…

  5. Global sensitivity analysis of a dynamic agroecosystem model under different irrigation treatments

    USDA-ARS?s Scientific Manuscript database

    Savings in consumptive use through limited or deficit irrigation in agriculture has become an increasingly viable source of additional water for places with high population growth such as the Colorado Front Range, USA. Crop models provide a mechanism to evaluate various management methods without pe...

  6. Rhizobacterial community structure and function in a dryland agroecosystem

    USDA-ARS?s Scientific Manuscript database

    We recently discovered large populations of phenazine-producing (Phz+) Pseudomonas strains and concentrations of the antibiotic phenazine-1-carboxylic acid (PCA) of up to 1.6 µg g-1 of root plus rhizosphere soil on roots of non-irrigated cereals grown over more than a million hectares of the Columbi...

  7. Applying spectral unmixing and support vector machine to airborne hyperspectral imagery for detecting giant reed

    USDA-ARS?s Scientific Manuscript database

    This study evaluated linear spectral unmixing (LSU), mixture tuned matched filtering (MTMF) and support vector machine (SVM) techniques for detecting and mapping giant reed (Arundo donax L.), an invasive weed that presents a severe threat to agroecosystems and riparian areas throughout the southern ...

  8. Agriculture and Biology Teaching. Science and Technology Education Document Series 11.

    ERIC Educational Resources Information Center

    Rao, A. N.; Pritchard, Alan J.

    The six-chapter document is part of Unesco's Science and Technology Education Programme to encourage an international exchange of ideas and information on science and technology education. Chapters discuss: (1) development of agriculture (beginning and modern); (2) agroecosystems (land utilization, soils, food production, irrigation, and…

  9. A weevil sex pheromone serves as an attractant for its entomopathogenic nematode predators

    USDA-ARS?s Scientific Manuscript database

    Diaprepes abbreviatus is an invasive pest of citrus in the United States originating from the Caribbean. Entomopathogenic nematodes (EPNs) are used as biological control agents in the citrus agroecosystems against D. abbreviatus. EPNs respond to herbivore-induced volatiles from citrus roots to assis...

  10. Manipulations of soil microbiota for C sequestration and mitigation of greenhouse gas emissions in managed systems

    USDA-ARS?s Scientific Manuscript database

    Soil microbes dominate processes that regulate soil trace gas emissions and soil C and N dynamics. Intensive management in agroecosystems provides unique opportunities to assess the effectiveness of microbial manipulations to enhance soil C retention and reduce trace gas emissions. While reduced til...

  11. LTAR linkages with other research networks: Capitalizing on network interconnections

    USDA-ARS?s Scientific Manuscript database

    The USDA ARS Research Unit based at the Jornada Experimental Range outside of Las Cruces, NM, is a member of the USDA’s Long Term Agro-ecosystem Research (LTAR) Network, the National Science Foundation’s Long Term Ecological Research (LTER) Network, the National Ecological Observation Network (NEON)...

  12. Interrogating the plasmidome to determine antibiotic resistance gene mobility within the swine fecal microbiota

    USDA-ARS?s Scientific Manuscript database

    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...

  13. Antibiotic Resistance in Agroecosystems: A One Health Perspective

    USDA-ARS?s Scientific Manuscript database

    Agriculture is, at its core, an embodiment of One Health principals, with the job of the farmer being to sustainably balance human, animal, and soil health. While these principles are a well-known part of the narrative for North American organic livestock and poultry farms, they are also embraced b...

  14. Evaluating bee (Hymenoptera: Apoidea) diversity using malaise traps in coffee landscapes of Costa Rica

    USDA-ARS?s Scientific Manuscript database

    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...

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

    USDA-ARS?s Scientific Manuscript database

    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. Glomalin as an indicator of mycorrhizae in tropical agroecosystems

    USDA-ARS?s Scientific Manuscript database

    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...

  17. Rhizosphere microorganisms affected by soil solarization and cover cropping in Capsicum annuum and Phaseolus lunatus agroecosystems

    USDA-ARS?s Scientific Manuscript database

    Field experiments were conducted to evaluate the effects of soil solarization or cover cropping on bell pepper (Capsicum annuum) and lima bean (Phaseolus lunatus, L.) rhizosphere microorganisms. In Experiment I, flat surface solarization (FSS), raised bed solarization (RBS), cowpea (Vigna unguiculat...

  18. Network cyberinfrastructure as a shared platform to support multi-site research

    USDA-ARS?s Scientific Manuscript database

    Multi-site research across the Long-term Agroecosystem Research (LTAR) network requires access to data and information. We present some existing examples where you can get data from across the network and summarize the rich inventory of measurements taken across LTAR sites. But data management suppo...

  19. The biophysical link between climate, water, and vegetation in bioenergy agro-ecosystems

    USDA-ARS?s Scientific Manuscript database

    Land use change for bioenergy feedstocks is likely to intensify as energy demand rises simultaneously with increased pressure to minimize greenhouse gas emissions. Initial assessments of the impact of adopting bioenergy crops as a significant energy source have largely focused on the potential for b...

  20. Halosulfuron reduced purple netsedge (Cyperus rotundus) tuber production and viability

    USDA-ARS?s Scientific Manuscript database

    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...

  1. Halosulfuron reduced purple nutsedge (Cyperus rotundus) tuber production and viability

    USDA-ARS?s Scientific Manuscript database

    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...

  2. Evaluating measures to assess soil health in long-term agroecosystem trials

    USDA-ARS?s Scientific Manuscript database

    Monitoring and assessing soil health is an important component of any land management system with a vision of sustaining soil resources. Soil organic matter(SOM)characteristics are key to soil health and responsive to tillage regime and crop management. As metrics of soil health, we evaluated surfac...

  3. Long-term rotation history and previous crop effects on corn seedling health

    USDA-ARS?s Scientific Manuscript database

    Diverse rotations provide benefits to agroecosystems through changes in the soil environment. A long term experiment was established to study four different four-year rotation sequences in which the crop phase prior to corn was sampled. Soils from rotations ending with soybean, sunflower, corn and p...

  4. Fruit metabolite networks in engineered and non-engineered tomato genotypes reveal fluidity in a hormone and agroecosystem specific manner

    USDA-ARS?s Scientific Manuscript database

    Multiple strategies have been explored throughout the world to meet food security. These include molecular breeding, transgenic genotype development, reduced-tillage crop production, modification of the soil environment with cover crops or polyethylene mulches and tunnels, and organic farming. Unde...

  5. Corn stover for advanced biofuels – Soil “Lorax” perspectives

    USDA-ARS?s Scientific Manuscript database

    Crop residues serve numerous agroecosystem function. Harvesting these materials must be done in a manner that protects the soil. Soil is the thin layer that stand be us and starvation. Strategies to protect the soil resource to balance current and future societal needs will be discussed....

  6. Runoff and sediment reduction from integration of native prairie filter strips into row-crop agriculture

    USDA-ARS?s Scientific Manuscript database

    Agroecosystems provide multiple benefits including food, fiber, fuel, clean water and air, habitat, carbon sequestration, recreation, and aesthetics. But most agricultural landscapes are managed for only a few of these benefits. This project aimed to evaluate how the integration of diverse perennial...

  7. Can foraging behavior of Criollo cattle help increase agricultural production and reduce environmental impacts in the arid Southwest?

    USDA-ARS?s Scientific Manuscript database

    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...

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

    EPA Science Inventory

    The development of effective measures to stabilize atmospheric 22 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 strengt...

  9. The Capacity-Building Stewardship Model: Assessment of an agricultural network as a mechanism for improving regional agroecosystem sustainability

    USDA-ARS?s Scientific Manuscript database

    Working lands have potential to meet agricultural production targets while serving as reservoirs of biological diversity and as sources of ecological services. Yet agricultural policy creates disincentives for this integration of conservation and production goals. While necessary, the development of...

  10. Short-term soil responses to late-seeded cover crops in a semi-arid environment

    USDA-ARS?s Scientific Manuscript database

    Cover crops can expand ecosystem services, though sound management recommendations for their use within semi-arid cropping systems is currently constrained by a lack of information. This study was conducted to determine agroecosystem responses to late-summer seeded cover crops under no-till managem...

  11. A comparison of the herbicide tolerances of rare and common plants in an agricultural landscape

    USDA-ARS?s Scientific Manuscript database

    Declining plant biodiversity in agroecosystems has often been attributed to escalating use of chemical herbicides, but other changes in farming practice including the clearing of semi-natural habitat fragments confound the influence of herbicides. In this paper, we introduce a new approach to evalua...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  13. Resilient populations of root fungi occur within five tomato production systems in Southeast Florida

    USDA-ARS?s Scientific Manuscript database

    Farming practices are known to impact arbuscular mycorrhizal (AM) fungi and other soil microbial communities in agroecosystems. The effects of divergent land management strategies on the incidence and infectivity of AM and other fungal root endophytes were evaluated in a 5-year tomato (Lycopersicon...

  14. Enzyme Activity Dynamics in Response to Climate Change: 2011 Drought-Heat Wave

    USDA-ARS?s Scientific Manuscript database

    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,...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  16. Response-Additional Implications of Perennial Bioenergy Crops: Hydrology and Climate

    USDA-ARS?s Scientific Manuscript database

    This is a response to a letter submitted in response to the Science article "Increasing Food and Ecosystem Security via Perennial Grains" written by Glover, et al. It details the balance of "precipitation use efficiency" in agroecosystems with the needs of sustainable food production and resiliency ...

  17. Simulating landscape catena effects in no-till dryland agroecosystems using GPFARM

    USDA-ARS?s Scientific Manuscript database

    Alternative agricultural management systems in the semi-arid Great Plains are receiving increasing attention. GPFARM is a farm/ranch decision support system (DSS) designed to assist in strategic management planning for land units from the field to the whole-farm level. This study evaluated the site...

  18. Atoxigenic Aspergillus flavus endemic to Italy for biocontrol of aflatoxins in maize

    USDA-ARS?s Scientific Manuscript database

    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...

  19. Soil Carbon Pools in Dryland Agroecosystems as Impacted By Several Years of Drought

    USDA-ARS?s Scientific Manuscript database

    No-till and increased cropping intensity (CI) can increase yield and soil organic carbon (SOC) in the US Great Plains compared with traditional wheat (Triticum aestivum L.) – fallow management. However, gains in SOC, and other C pools, may not be permanent. Increasing frequency of drought may redu...

  20. Rye cover crop effects on soil properties in no-till corn silage/soybean agroecosystems

    USDA-ARS?s Scientific Manuscript database

    Farmers in the U.S. Corn Belt are showing increasing interest in winter cover crops. The known benefits of winter cover crops include reduced nitrate leaching, soil erosion, and weed germination, but evidence of improvements in soil productivity would provide further incentive for famers to implemen...

  1. The first nitrogen index app for mobile devices: using portable technology for smart agricultural management

    USDA-ARS?s Scientific Manuscript database

    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...

  2. Nitrogen balance in response to dryland crop rotations and cultural practices

    USDA-ARS?s Scientific Manuscript database

    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...

  3. Sugar concentration and timing of feeding affect feeding characteristics and survival of a parasitic wasp

    USDA-ARS?s Scientific Manuscript database

    The availability of food sources is critical for parasitoid survival, especially for those that do not host-feed, or in agroecosystems where nectar and honeydew are sometimes spatially and temporally scarce. Therefore, the value of even a single meal can be crucial for survival. Psyttalia lounsbur...

  4. The effect of flowering calendula and cuphea plants on Orius insidiosus survival and predation of Aphis glycines

    USDA-ARS?s Scientific Manuscript database

    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...

  5. Soil functional zone management: a vehicle for enhancing production and soil ecosystem services in row-crop agroecosystems

    USDA-ARS?s Scientific Manuscript database

    There is increasing demand for food, bioenergy feedstocks and a wide variety of bio-based products. In response, agriculture has made great gains in production, but is increasingly depleting soil regulating and supporting ecosystem services. New production systems have emerged, such as Conservation ...

  6. ASSESSING THE INFLUENCE OF PLANT GROWTH REGULATOR HERBICIDE VAPOR DRIFT ON ARTHROPOD COMMUNITIES IN FIELD CROP AGRO-ECOSYSTEMS

    EPA Science Inventory

    Sub-lethal herbicide damage is likely to have negative consequences for plant health. This in turn could lead to positive or negative effects on insects. Plants that are not healthy may not provide the best floral resources for pollinators, potentially further stressing hon...

  7. Measurements and models to identify agroecosystem practices that enhance soil organic carbon under changing climate

    USDA-ARS?s Scientific Manuscript database

    Adapting to the anticipated impacts of climate change is a pressing issue facing agriculture, as precipitation and temperature changes are expected to have major effects on agricultural production in many regions of the world. These changes will also affect soil organic matter (SOM) decomposition an...

  8. Landscape Patterns and Their Influence on Bird Communities Resulting from Agricultural Policies Promoting Shelterbelts in Eastern Nebraska

    Treesearch

    Robert A., II Pierce; D. Todd Farrand; William B. Kurtz; Jim Brandle; Ron Johnson

    2003-01-01

    Evolving agricultural policies and technologies have influenced land management practices within agroecosystems, impacting available habitats for many species of wildlife. Increasing available wildlife habitat and enhancing habitat quality have become an explicit objective of existing agricultural policy. Thus, there is renewed focus on utilizing shelterbelt...

  9. Temporal scaling of episodic point estimates of weed seed predation to long-term predation rates

    USDA-ARS?s Scientific Manuscript database

    Weed seed predation is an important ecosystem service supporting weed management in low-external-input agroecosystems. For convenience, measurements of seed predation are often made at very short time scales (< 3 d). However, one of the primary uses of such data, the parameterization of models of cr...

  10. Mapping giant reed along the Rio Grande using airborne and satellite imagery

    USDA-ARS?s Scientific Manuscript database

    Giant reed (Arundo donax L.) is a perennial invasive weed that presents a severe threat to agroecosystems and riparian areas in the Texas and Mexican portions of the Rio Grande Basin. The objective of this presentation is to give an overview on the use of aerial photography, airborne multispectral a...

  11. Impacts of crop sequence and tillage management on soil carbon stocks in south-central North Dakota, USA

    USDA-ARS?s Scientific Manuscript database

    Increased emphasis has been placed on developing agroecosystems that are robust, highly productive, economically competitive, and environmentally benign. After 18 years of a study to evaluate effects of crop sequence and tillage, we measured soil properties at various depths to 3 feet (91.4 cm) and ...

  12. Comparative Biogeochemical Cycles of Bioenergy Crops Reveal Nitrogen-Fixation and Low GHG Emissions in a Miscanthus x giganteus Agro-ecosystem

    USDA-ARS?s Scientific Manuscript database

    We evaluated the relative greenhouse gas mitigation potential of plant species considered as biofuel feedstock crops by simulating the biogeochemical processes associated with Miscanthus x giganteus, Panicum virgatum, Zea mays, and a mixed prairie community. DayCent model simulations for Miscanthus ...

  13. Simulation of high frequency nitrous oxide emissions from irrigated sub-tropical soils using DAYCENT

    USDA-ARS?s Scientific Manuscript database

    A unique high temporal frequency dataset from an irrigated cotton-wheat rotation was used to test the agroecosystem model DayCent to simulate daily N2O emissions from sub-tropical vertisols under different irrigation intensities. DayCent was able to simulate the effect of different irrigation intens...

  14. Soil microbial responses to elevated CO2 and O3 in a nitrogen-aggrading agroecosystem

    USDA-ARS?s Scientific Manuscript database

    Despite decades of study, the underlying mechanisms by which soil microbes respond to rising atmospheric CO2 and ozone remain poorly understood. A prevailing hypothesis, which states that changes in C availability induced by elevated CO2 and ozone drive alterations in soil microbes and the processe...

  15. Protein discovery: combined transcriptomic and proteomic analyses of venom from the endoparasitoid Cotesia chilonis (Hymenoptera: Brachonidae)

    USDA-ARS?s Scientific Manuscript database

    Background: Many species of endoparasitoid wasps provide biological control services in agroecosystems. Although there is a great deal of information on the ecology and physiology of host/parasitoid interactions, relatively little is known on the protein composition of venom and how specific venom p...

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

    EPA Science Inventory

    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...

  17. Predator in First: A prophylactic biological control strategy for management of multiple pests of pepper

    USDA-ARS?s Scientific Manuscript database

    The establishment of biocontrol agents is critical for success of biological control strategies. Predator-In-First (PIF) is a prophylactic control strategy that aims to establish predators before the appearance of pests in an agro-ecosystem. Predator-In-First uses the characteristics of generalist p...

  18. Soil organic carbon stability across a Mediterranean oak agroecosystem

    Treesearch

    Leslie M. Roche; James F. Chang; Johan Six; Anthony T. O' Geen; Kenneth W. Tate

    2015-01-01

    Rangelands are estimated to cover 30 to 50 percent of the world's land surface and have significant belowground carbon (C) storage potential. Given their geographical extent, many have suggested that even modest changes in C storage via management practices could alter the global C cycle, creating climate change mitigation opportunities. Our objective was to...

  19. Operationalizing an "Information Ecosystem" to support information management work of the Long-Term Agroecosystem Research (LTAR) network

    USDA-ARS?s Scientific Manuscript database

    As data collection ramps up across the LTAR Network, the “information ecosystem” (Kaplan et al. 2016 and Nardi and O’Day, 1999) must support three domains of sustainable agriculture, and data flow needs to be operationalized. Approaches to prioritizing, designing, and developing shared cyberinfrastr...

  20. LTAR information management: Six examples of data intensive work at site and network levels

    USDA-ARS?s Scientific Manuscript database

    Information systems for managing research data from the Long-term Agroecosystem Research (LTAR) program are implemented at site and network levels. Different information management tools are necessary to manage a variety of data types. There is no one-size fits all solution for managing all LTAR dat...

  1. Microbial community structure is affected by cropping sequences and poultry litter under long-term no-tillage

    USDA-ARS?s Scientific Manuscript database

    Soil microorganisms play essential roles in soil organic matter dynamics and nutrient cycling in agroecosystems and have been used as soil quality indicators. The response of soil microbial communities to land management is complex and the long-term impacts of cropping systems on soil microbes is l...

  2. Development of the Long-Term Agro-ecosystem Research (LTAR) Network: Current status and future trends

    USDA-ARS?s Scientific Manuscript database

    Long-term research conducted at multiple scales is critical to assessing the effects of key long term drivers (e.g., global population growth; land-use change; increased competition for natural resources; climate variability and change) on our ability to sustain or enhance agricultural production to...

  3. Characterization of antibiotic resistant (AR) fecal indicators in runoff from fields amended with swine manure

    USDA-ARS?s Scientific Manuscript database

    The application of animal manures to agricultural soil is a widespread practice. One concern associated with food animal manures is the introduction of antibiotic drugs, AR bacteria, and AR genes that may be spread through and across agroecosystems, with the potential to adversely impact the treatm...

  4. Gall midges (Diptera: Cecidomyiidae) in forest ecosystems

    Treesearch

    Marcela Skuhrav& #225; ; Marcela NO-VALUE

    1991-01-01

    The family Cecidomyiidae is one of the largest of the Diptera. Gall midges are small, inconspicuous flies, but they may be very important both in forest ecosystems and in agroecosystems. Many phytophagous gall midge species attack forest trees, and some of them can be serious pests, such as the Dasineura rozhkovii Mamaev and Nikolsky, which develops...

  5. Manipulation of soil microbes using higher biomass cropping systems to sustain soil health in cotton-based agroecosystems

    USDA-ARS?s Scientific Manuscript database

    The semiarid Texas High Plains produces ~30% of U.S. cotton (Gossypium hirsutum L.). Agricultural production, however, is experiencing a transition from irrigated to dryland crop production due to reductions in water availability from the Ogallala aquifer. Additional challenges are imposed by extrem...

  6. Elevated [CO2] modified the drought acclimation response in peanut

    USDA-ARS?s Scientific Manuscript database

    Peanut agroecosystems play a key role in food production and are a major source of protein in many arid and semi-arid regions where extreme weather events are expected to increase in frequency. We are taking a systems-level approach to investigate the response of peanut to elevated [CO2], water defi...

  7. Impacts of alternative climate information on hydrologic processes with SWAT: A comparison of NCDC, PRISM and NEXRAD datasets

    USDA-ARS?s Scientific Manuscript database

    Precipitation and temperature are two primary drivers that significantly affect hydrologic processes in a watershed. A network of land-based National Climatic Data Center (NCDC) weather stations has been typically used as a primary source of climate input for agro-ecosystem models. However, the ne...

  8. Cry1Ab expression rice does not influence expression of fecundity related genes in the wolf spider Pardosa pseudoannulata

    USDA-ARS?s Scientific Manuscript database

    The impact of Bacillus thuringiensis (Bt) toxin proteins on the arthropod assemblages in rice agroecosystems, including non-target predatory arthropods, has been well documented. However, the influence of Bt toxins on predators remains understudied at the cellular and molecular levels. Here, we inve...

  9. Erosion and runoff evaluation in Goodwater Creek Experimental Watershed using the SWAT-T Model

    USDA-ARS?s Scientific Manuscript database

    The 72 km2 Goodwater Creek Experimental Watershed (GCEW), in the claypan region, is a Long-Term Agro-ecosystem Research Watershed in Boone and Audrain counties of north-central MO, which has reported problems with degraded water quality from nutrients, sediment, and herbicides. Terraces are effectiv...

  10. Soil health research in the Goodwater Creek Experimental Watershed Long-Term Agroecosystem Research site

    USDA-ARS?s Scientific Manuscript database

    The Goodwater Creek Experimental Watershed (GCEW) is located in the Central Claypan Region in NE Missouri. Within GCEW, a field and plot research site has been operated by the USDA-Agricultural Research Service (ARS) Cropping Systems and Water Quality Research Unit since 1991. The GCEW site joined t...

  11. Explaining abrupt spatial transitions in agro-ecosystem responses to periods of extended drought

    USDA-ARS?s Scientific Manuscript database

    During the 1930’s, the North American central grassland region (CGR) experienced an extreme multi-year drought that resulted in broad scale plant mortality, massive dust storms and losses of soil and nutrients. Southern mixed grasslands were among the worst affected and experienced severe broad scal...

  12. ASSESSING POSSIBLE ECOLOGICAL RISKS OF GENETICALLY MODIFIED CROPS: GENE EXPRESSION ASSAYS AND GENETIC MONITORING OF NON-TARGET ORGANISMS

    EPA Science Inventory

    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...

  13. Soil aggregation as mechanism for understanding the roles of soil biota in the sustainable usage of natural resources

    USDA-ARS?s Scientific Manuscript database

    Global food insecurity and rapidly diminishing water, soil, and energy resources resulting from increases in population numbers and wealth are putting pressure on agroecosystems to efficiently produce the most nutrient dense food while maintaining or enhancing natural resources. To address these ne...

  14. Predation of Halyomorpha halys (Hemiptera: Pentatomidae) from web-building spiders associated with anthropogenic dwellings

    USDA-ARS?s Scientific Manuscript database

    The brown marmorated stink bug or Halyomorpha halys is an invasive pest from Asia that causes severe agricultural damage and nuisance problems for homeowners. While the natural enemy community of H. halys has been evaluated in several agroecosystems, it has not been quantified where H. halys overwi...

  15. Biosolids and dredged materials: alternative sources of nutrients for crop productivity and sustainability of pasture-based agroecosystem

    USDA-ARS?s Scientific Manuscript database

    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...

  16. NERISK: AN EXPERT SYSTEM TO ENHANCE THE INTEGRATION OF PESTICIDES WITH ARTHROPOD BIOLOGICAL CONTROL

    EPA Science Inventory

    An expert system termed NERISK was developed to evaluate the effects of pesticides on arthropod predators and parasitoids in a variety of agroecosystems. ased on a shell system (RECOG) with minor coding modifications, the system was designed to let even a novice user access the v...

  17. The Hawaii protocol for scientific monitoring of coffee berry borer: a model for coffee agroecosystems worldwide

    USDA-ARS?s Scientific Manuscript database

    Coffee Berry Borer (CBB) is the most devastating insect pest for coffee crops worldwide. We developed a scientific monitoring protocol aimed at capturing and quantifying the dynamics and impact of this invasive insect pest as well as the development of its host plant across a heterogeneous landscape...

  18. Long-term agroecosystem research in the Central Mississippi River Basin: hyperspectral remote sensing of reservoir water quality

    USDA-ARS?s Scientific Manuscript database

    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 e...

  19. Net global warming potential and greenhouse gas intensity influenced by irrigation, tillage, crop rotation, and nitrogen fertilization

    USDA-ARS?s Scientific Manuscript database

    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...

  20. Simulated climate-warming increases Coleoptera activity-densities and reduces community diversity in a cereal crop

    USDA-ARS?s Scientific Manuscript database

    To assess one likely effect of global warming, we experimentally increased the temperature and precipitation of a coleopteran community (mainly Carabidae) of an agro-ecosystem. We simulated climate change on a field of spring wheat by experimentally increasing the temperature by 2°C using infrared h...

  1. Path analyses of grain P, Zn, Cu, Fe, and Ni in a biosolids-amended dryland wheat agroecosystem

    USDA-ARS?s Scientific Manuscript database

    Biosolids land application is an effective means of recycling plant nutrients and is the preferred method of biosolids reuse by the US Environmental Protection Agency. One issue concerning biosolids application is the extent of the contribution of biosolids-borne plant nutrients to the overall crop...

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

    USDA-ARS?s Scientific Manuscript database

    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 ...

  3. Tillage, crop rotation, and cultural practice impact on nitrogen balance under dryland cropping systems

    USDA-ARS?s Scientific Manuscript database

    Accounting of N inputs and outputs and N retention in the soil provides N balance that measures agroecosystem performance and environmental sustainability. Because of the complexity of measurements of some N inputs and outputs, studies on N balance in long-term experiments are scanty. We examined th...

  4. Hydraulic redistribution by two semi-arid shrub species: implications for Sahelian agro-ecosystems

    Treesearch

    F. Kizito; M.I. Dragila; M. Sene; J.R. Brooks; F.C. Meinzer; I. Diedhiou; M. Diouf; A. Lufafa; R.P. Dick; J. Selker; R. Cuenca

    2012-01-01

    Hydraulic redistribution is the process of passive water movement from deeper moist soil to shallower dry soil layers using plant roots as conduits. Results from this study indicate that this phenomenon exists among two shrub species (Guiera senegalensis and Piliostigma reticulatum) that co-exist with annual food crops in...

  5. Long-term application of the Crop Water Stress Index in Midwest agro-ecosystems

    USDA-ARS?s Scientific Manuscript database

    Agricultural land in the Midwestern US is largely used for rainfed corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) production. The native ecosystems in this region predominantly consist of tallgrass prairie. Water stress can occur in summer which can affect carbon assimilation of those agro-...

  6. A New GIS-Nitrogen Trading Tool Concept to Minimize Reactive Nitrogen losses to the Environment

    USDA-ARS?s Scientific Manuscript database

    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...

  7. LTAR research: Aspiring to meet production and conservation objectives on the USDA-ARS Central Plains Experimental Range, Nunn, Colorado, USA

    USDA-ARS?s Scientific Manuscript database

    The Long-Term Agroecosystem Research (LTAR) Network consists of 18 sites across the continental United States (US) sponsored by the US Department of Agriculture, Agricultural Research Service, universities and non-governmental organizations. LTAR scientists seek to determine ways to ensure sustainab...

  8. Exclusion of agricultural lands in spatial conservation prioritization strategies: consequences for biodiversity and ecosystem service representation.

    PubMed

    Durán, América P; Duffy, James P; Gaston, Kevin J

    2014-10-07

    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. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  9. Bat-Fruit Interactions Are More Specialized in Shaded-Coffee Plantations than in Tropical Mountain Cloud Forest Fragments

    PubMed Central

    Hernández-Montero, Jesús R.; Saldaña-Vázquez, Romeo A.; Galindo-González, Jorge; Sosa, Vinicio J.

    2015-01-01

    Forest disturbance causes specialization of plant-frugivore networks and jeopardizes mutualistic interactions through reduction of ecological redundancy. To evaluate how simplification of a forest into an agroecosystem affects plant-disperser mutualistic interactions, we compared bat-fruit interaction indexes of specialization in tropical montane cloud forest fragments (TMCF) and shaded-coffee plantations (SCP). Bat-fruit interactions were surveyed by collection of bat fecal samples. Bat-fruit interactions were more specialized in SCP (mean H2 ' = 0.55) compared to TMCF fragments (mean H2 ' = 0.27), and were negatively correlated to bat abundance in SCP (R = -0.35). The number of shared plant species was higher in the TMCF fragments (mean = 1) compared to the SCP (mean = 0.51) and this was positively correlated to the abundance of frugivorous bats (R= 0.79). The higher specialization in SCP could be explained by lower bat abundance and lower diet overlap among bats. Coffee farmers and conservation policy makers must increase the proportion of land assigned to TMCF within agroecosystem landscapes in order to conserve frugivorous bats and their invaluable seed dispersal service. PMID:25992550

  10. Bat-fruit interactions are more specialized in shaded-coffee plantations than in tropical mountain cloud forest fragments.

    PubMed

    Hernández-Montero, Jesús R; Saldaña-Vázquez, Romeo A; Galindo-González, Jorge; Sosa, Vinicio J

    2015-01-01

    Forest disturbance causes specialization of plant-frugivore networks and jeopardizes mutualistic interactions through reduction of ecological redundancy. To evaluate how simplification of a forest into an agroecosystem affects plant-disperser mutualistic interactions, we compared bat-fruit interaction indexes of specialization in tropical montane cloud forest fragments (TMCF) and shaded-coffee plantations (SCP). Bat-fruit interactions were surveyed by collection of bat fecal samples. Bat-fruit interactions were more specialized in SCP (mean H2 ' = 0.55) compared to TMCF fragments (mean H2 ' = 0.27), and were negatively correlated to bat abundance in SCP (R = -0.35). The number of shared plant species was higher in the TMCF fragments (mean = 1) compared to the SCP (mean = 0.51) and this was positively correlated to the abundance of frugivorous bats (R= 0.79). The higher specialization in SCP could be explained by lower bat abundance and lower diet overlap among bats. Coffee farmers and conservation policy makers must increase the proportion of land assigned to TMCF within agroecosystem landscapes in order to conserve frugivorous bats and their invaluable seed dispersal service.

  11. The Socioecology of Territory Size and a "Work-Around" Hypothesis for the Adoption of Farming

    PubMed Central

    Freeman, Jacob

    2016-01-01

    This paper combines theory from ecology and anthropology to investigate variation in the territory sizes of subsistence oriented agricultural societies. The results indicate that population and the dependence of individuals within a society on “wild” foods partly determine the territory sizes of agricultural societies. In contrast, the productivity of an agroecosystem is not an important determinant of territory size. A comparison of the population-territory size scaling dynamics of agricultural societies and human foragers indicates that foragers and farmers face the same constraints on their ability to expand their territory and intensify their use of resources within a territory. However, the higher density of food in an agroecosystem allows farmers, on average, to live at much higher population densities than human foragers. These macroecological patterns are consistent with a “work-around hypothesis” for the adoption of farming. This hypothesis is that as residential groups of foragers increase in size, farming can sometimes better reduce the tension between an individual’s autonomy over resources and the need for social groups to function to provide public goods like defense and information. PMID:27391955

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

    PubMed

    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 < 0.05) improved the farmers cash income than non-tree based garden. With insignificant garden size; 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.

  13. [Using ecology thinking reconstructing traditional agronomy: role of production ecology].

    PubMed

    Wang, Song-Liang

    2012-08-01

    Traditional agronomy, as a discipline or specialty, is originated from the reductionism thinking of neoteric experimental sciences and motivated by the great success of industrialized revolution, but loses the ensemble grasp of the relationships between agricultural organisms and their resources and environment, i.e., agroecosystem mechanism. Moreover, due to the excessively relying on exogenous fossil energy input and the monoculture with a few highly productive crop cultivars, the agricultural interior sustainability has unceasingly lost, making our mankind facing the double crises of grain security and food safety. Therefore, it is imperative to reconstruct the traditional agronomy and its educational system. In this paper, the author proposed to link traditional agronomy with ecology, establishing agroecology as the core subject and agroecosystem management as the core applied system, and in particular, establishing 'production ecology' to fill up the wide gap between the crop cultivation and farming system and the crop genetics and breeding, the two second grade disciplines under agronomy. Ideologically and methodologically, this proposal could provide disciplinary, scientific, and educational bases to authentically implement the strategy of sustainable development of agriculture.

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

    PubMed

    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.

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

    USGS Publications Warehouse

    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 < 0.045). Growers may benefit from balancing the N inputs from hydrologic sources and OM relative to 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.

  16. Tree spatial structure, host composition and resource availability influence mirid density or black pod prevalence in cacao agroforests in Cameroon.

    PubMed

    Gidoin, Cynthia; Babin, Régis; Bagny Beilhe, Leïla; Cilas, Christian; ten Hoopen, Gerben Martijn; Bieng, Marie Ange Ngo

    2014-01-01

    Combining crop plants with other plant species in agro-ecosystems is one way to enhance ecological pest and disease regulation mechanisms. Resource availability and microclimatic variation mechanisms affect processes related to pest and pathogen life cycles. These mechanisms are supported both by empirical research and by epidemiological models, yet their relative importance in a real complex agro-ecosystem is still not known. Our aim was thus to assess the independent effects and the relative importance of different variables related to resource availability and microclimatic variation that explain pest and disease occurrence at the plot scale in real complex agro-ecosystems. The study was conducted in cacao (Theobroma cacao) agroforests in Cameroon, where cocoa production is mainly impacted by the mirid bug, Sahlbergella singularis, and black pod disease, caused by Phytophthora megakarya. Vegetation composition and spatial structure, resource availability and pest and disease occurrence were characterized in 20 real agroforest plots. Hierarchical partitioning was used to identify the causal variables that explain mirid density and black pod prevalence. The results of this study show that cacao agroforests can be differentiated on the basis of vegetation composition and spatial structure. This original approach revealed that mirid density decreased when a minimum number of randomly distributed forest trees were present compared with the aggregated distribution of forest trees, or when forest tree density was low. Moreover, a decrease in mirid density was also related to decreased availability of sensitive tissue, independently of the effect of forest tree structure. Contrary to expectations, black pod prevalence decreased with increasing cacao tree abundance. By revealing the effects of vegetation composition and spatial structure on mirids and black pod, this study opens new perspectives for the joint agro-ecological management of cacao pests and diseases at the plot scale, through the optimization of the spatial structure and composition of the vegetation.

  17. Study of mosquito fauna in rice ecosystems around Hanoi, northern Vietnam.

    PubMed

    Ohba, Shin-ya; Van Soai, Nguyen; Van Anh, Dinh Thi; Nguyen, Yen T; Takagi, Masahiro

    2015-02-01

    Species of the Culex vishnui subgroup, Cx. fuscocephala and Cx. gelidus, which are known Japanese encephalitis (JE) vectors, are distributed in rice agroecosystems in Asian countries. Hence, although ecological studies of rice agroecosystems in northern Vietnam are necessary, very few integrated studies of breeding habitats of mosquitoes, including JE vectors, have been conducted. We carried out a field study and investigated the mosquito fauna in six rice production areas in northern Vietnam during the rainy and dry seasons of 2009. Mosquitoes and potential mosquito predators were collected from aquatic habitats by using larval dippers. We collected 1780 Culex individuals (including 254 Cx. tritaeniorhynchus; 113 Cx. vishnui, 58 Cx. vishnui complex, consisting of Cx. vishnui and Cx. pseudovishnui; 12 Cx. gelidus; 1 Cx. bitaeniorhynchus; and 1 Cx. fuscocephala), 148 Anopheles individuals (including 5 An. vagus), 1 Mansonia annulifera, and 1 Mimomyia chamberlaini during the rainy season. During the dry season, we collected 176 Culex individuals (including 33 Cx. vishnui, 24 Cx. tritaeniorhynchus, 8 Cx. vishnui complex, and 1 Cx. gelidus) and 186 Anopheles individuals (including 9 An. tessellatus, 2 An. kochi, and 2 An. barbumbrosus). We found mosquitoes in all aquatic habitats, namely, rice fields, ditches, ponds, wetlands, irrigation canals, and rice nurseries, and Cx. tritaeniorhynchus and Cx. vishnui complex were found in all the above six areas. Heteroptera such as Micronecta, Veliidae, and Pleidae were abundant and widely distributed in both the seasons. The abundance of mosquito larvae was higher in the rice fields, ditches, and ponds during the rainy season than during the dry season. Cx. tritaeniorhynchus, Cx. vishnui complex, Cx. fuscocephala, and Cx. gelidus were abundant in rice agroecosystems (rice fields, ditches, ponds, and wetlands) in northern Vietnam, and their abundance was high during the rainy season. These findings deepen our understanding of mosquito ecology and strengthen mosquito control strategies to be applied in rice ecosystems Vietnam in the future. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Injury Profile SIMulator, a Qualitative Aggregative Modelling Framework to Predict Crop Injury Profile as a Function of Cropping Practices, and the Abiotic and Biotic Environment. I. Conceptual Bases

    PubMed Central

    Aubertot, Jean-Noël; Robin, Marie-Hélène

    2013-01-01

    The limitation of damage caused by pests (plant pathogens, weeds, and animal pests) in any agricultural crop requires integrated management strategies. Although significant efforts have been made to i) develop, and to a lesser extent ii) combine genetic, biological, cultural, physical and chemical control methods in Integrated Pest Management (IPM) strategies (vertical integration), there is a need for tools to help manage Injury Profiles (horizontal integration). Farmers design cropping systems according to their goals, knowledge, cognition and perception of socio-economic and technological drivers as well as their physical, biological, and chemical environment. In return, a given cropping system, in a given production situation will exhibit a unique injury profile, defined as a dynamic vector of the main injuries affecting the crop. This simple description of agroecosystems has been used to develop IPSIM (Injury Profile SIMulator), a modelling framework to predict injury profiles as a function of cropping practices, abiotic and biotic environment. Due to the tremendous complexity of agroecosystems, a simple holistic aggregative approach was chosen instead of attempting to couple detailed models. This paper describes the conceptual bases of IPSIM, an aggregative hierarchical framework and a method to help specify IPSIM for a given crop. A companion paper presents a proof of concept of the proposed approach for a single disease of a major crop (eyespot on wheat). In the future, IPSIM could be used as a tool to help design ex-ante IPM strategies at the field scale if coupled with a damage sub-model, and a multicriteria sub-model that assesses the social, environmental, and economic performances of simulated agroecosystems. In addition, IPSIM could also be used to help make diagnoses on commercial fields. It is important to point out that the presented concepts are not crop- or pest-specific and that IPSIM can be used on any crop. PMID:24019908

  19. Tree Spatial Structure, Host Composition and Resource Availability Influence Mirid Density or Black Pod Prevalence in Cacao Agroforests in Cameroon

    PubMed Central

    Gidoin, Cynthia; Babin, Régis; Bagny Beilhe, Leïla; Cilas, Christian; ten Hoopen, Gerben Martijn; Bieng, Marie Ange Ngo

    2014-01-01

    Combining crop plants with other plant species in agro-ecosystems is one way to enhance ecological pest and disease regulation mechanisms. Resource availability and microclimatic variation mechanisms affect processes related to pest and pathogen life cycles. These mechanisms are supported both by empirical research and by epidemiological models, yet their relative importance in a real complex agro-ecosystem is still not known. Our aim was thus to assess the independent effects and the relative importance of different variables related to resource availability and microclimatic variation that explain pest and disease occurrence at the plot scale in real complex agro-ecosystems. The study was conducted in cacao (Theobroma cacao) agroforests in Cameroon, where cocoa production is mainly impacted by the mirid bug, Sahlbergella singularis, and black pod disease, caused by Phytophthora megakarya. Vegetation composition and spatial structure, resource availability and pest and disease occurrence were characterized in 20 real agroforest plots. Hierarchical partitioning was used to identify the causal variables that explain mirid density and black pod prevalence. The results of this study show that cacao agroforests can be differentiated on the basis of vegetation composition and spatial structure. This original approach revealed that mirid density decreased when a minimum number of randomly distributed forest trees were present compared with the aggregated distribution of forest trees, or when forest tree density was low. Moreover, a decrease in mirid density was also related to decreased availability of sensitive tissue, independently of the effect of forest tree structure. Contrary to expectations, black pod prevalence decreased with increasing cacao tree abundance. By revealing the effects of vegetation composition and spatial structure on mirids and black pod, this study opens new perspectives for the joint agro-ecological management of cacao pests and diseases at the plot scale, through the optimization of the spatial structure and composition of the vegetation. PMID:25313514

  20. Pathogen evolution across the agro-ecological interface: implications for disease management.

    PubMed

    Burdon, Jeremy J; Thrall, Peter H

    2008-02-01

    Infectious disease is a major causal factor in the demography of human, plant and animal populations. While it is generally accepted in medical, veterinary and agricultural contexts that variation in host resistance and pathogen virulence and aggressiveness is of central importance to understanding patterns of infection, there has been remarkably little effort to directly investigate causal links between population genetic structure and disease dynamics, and even less work on factors influencing host-pathogen coevolution. The lack of empirical evidence is particularly surprising, given the potential for such variation to not only affect disease dynamics and prevalence, but also when or where new diseases or pathotypes emerge. Increasingly, this lack of knowledge has led to calls for an integrated approach to disease management, incorporating both ecological and evolutionary processes. Here, we argue that plant pathogens occurring in agro-ecosystems represent one clear example where the application of evolutionary principles to disease management would be of great benefit, as well as providing model systems for advancing our ability to generalize about the long-term coevolutionary dynamics of host-pathogen systems. We suggest that this is particularly the case given that agro-ecological host-pathogen interactions represent a diversity of situations ranging from those that only involve agricultural crops through to those that also include weedy crop relatives or even unrelated native plant communities. We begin by examining some of the criteria that are important in determining involvement in agricultural pathogen evolution by noncrop plants. Throughout we use empirical examples to illustrate the fact that different processes may dominate in different systems, and suggest that consideration of life history and spatial structure are central to understanding dynamics and direction of the interaction. We then discuss the implications that such interactions have for disease management in agro-ecosystems and how we can influence those outcomes. Finally, we identify several major gaps where future research could increase our ability to utilize evolutionary principles in managing disease in agro-ecosystems.

  1. Land-use change in Indian tropical agro-ecosystems: eco-energy estimation for socio-ecological sustainability.

    PubMed

    Nautiyal, Sunil; Kaechele, Harald; Umesh Babu, M S; Tikhile, Pavan; Baksi, Sangeeta

    2017-04-01

    This study was carried out to understand the ecological and economic sustainability of floriculture and other main crops in Indian agro-ecosystems. The cultivation practices of four major flower crops, namely Jasminum multiflorum, Crossandra infundibuliformis, Chrysanthemum and Tagetes erecta, were studied in detail. The production cost of flowers in terms of energy was calculated to be 99,622-135,996 compared to 27,681-69,133 MJ ha -1 for the main crops, namely Oryza sativa, Eleusine coracana, Zea mays and Sorghum bicolor. The highest-energy input amongst the crops was recorded for Z. mays (69,133 MJ ha -1 ) as this is a resource-demanding crop. However, flower cultivation requires approximately twice the energy required for the cultivation of Z. mays. In terms of both energy and monetary inputs, flower cultivation needs two to three times the requirements of the main crops cultivated in the region. The monetary inputs for main crop cultivation were calculated to be ₹ 27,349 to ₹ 46,930 as compared to flower crops (₹ 62,540 to ₹ 144,355). Floriculture was found to be more efficient in monetary terms when compared to the main crops cultivated in the region. However, the energy efficiency of flower crops is lower than that of the main crops, and the energy output from flower cultivation was found to be declining in tropical agro-ecosystems in India. Amongst the various inputs, farmyard manure accounts for the highest proportion, and for its preparation, most of the raw material comes from the surrounding ecosystems. Thus, flower cultivation has a direct impact on the ecosystem resource flow. Therefore, keeping the economic and environmental sustainability in view, this study indicates that a more field-based research is required to frame appropriate policies for flower cultivation to achieve sustainable socio-ecological development.

  2. Agroecosystem productivity in a warmer and CO2 enriched atmosphere

    NASA Astrophysics Data System (ADS)

    Bernacchi, Carl; Köhler, Iris; Ort, Donald; Long, Steven; Clemente, Thomas

    2017-04-01

    A number of in-field manipulative experiments have been conducted that address the response of key ecosystem services of major agronomic species to rising CO2. Global warming, however, is inextricably linked to rising greenhouse gases in general, of which CO2 is the most dominant. Therefore, agroecosystem functioning in future conditions requires an understanding of plant responses to both rising CO2 and increased temperatures. Few in-field manipulative experiments have been conducted that supplement both heating and CO2 above background concentrations. Here, the results of six years of experimentation using a coupled Free Air CO2 Enrichment (FACE) technology with variable output infrared heating arrays are reported. The manipulative experiment increased temperatures (+ 3.5˚ C) and CO2 (+ 200 μmol mol-1) above background levels for on two major agronomic crop species grown throughout the world, Zea mays (maize) and Glycine max (soybean). The first phase of this research addresses the response of plant physiological parameters to growth in elevated CO2 and warmer temperatures for maize and soybean grown in an open-air manipulative experiment. The results show that any increase in ecosystem productivity associated with rising CO2 is either similar or is offset by growth at higher temperatures, inconsistent with the perceived benefits of higher CO2 plus warmer temperatures on agroecosystem productivity. The second phase of this research addresses the opportunity to genetically modify soybean to allow for improved productivity under high CO2 and warmer temperatures by increasing a key photosynthetic carbon reduction cycle enzyme, SPBase. The results from this research demonstrates that manipulation of the photosynthetic pathway can lead to higher productivity in high CO2 and temperature relative to the wild-type control soybean. Overall, this research advances the understanding of the physiological responses of two major crops, and the impact on ecosystem services, to atmospheric conditions with the ultimate goals of better understanding agronomic responses to global change and improved representation of these processes in ecosystem models.

  3. Simulating grazing practices in a complete livestock system model: estimating soil carbon storage and greenhouse gas emissions in grazed versus un-grazed agroecosystems using the Manure-DNDC model

    NASA Astrophysics Data System (ADS)

    Campbell, E. E.; Dorich, C.; Contosta, A.; Varner, R. K.

    2017-12-01

    In livestock agroecosystems, the combined contributions of enteric fermentation, manure management, and livestock grazing and/or feed production play an important role in agroecosystem carbon (C) storage and GHG losses, with complete livestock system models acting as important tools to evaluate the full impacts of these complex systems. The Manure-DeNitrification-DeComposition (DNDC) model is one such example, simulating impacts on C and nitrogen cycling, estimating methane, carbon dioxide, nitrous oxide, and ammonium dynamics in fields, manure storage, and enteric emissions. This allows the evaluation of differences in GHG and soil C impacts between conventional and organic dairy production systems, which differ in their use of grazed pasture versus confined feeding operations. However, Manure-DNDC has received limited testing in representing variations in grazed pasture management (i.e. intensive rotational grazing versus standard grazing practices). Using a set of forage biomass, soil C, and GHG emissions data collected at four sites across New England, we parameterized and validated Manure-DNDC estimations of GHG emissions and soil C in grazed versus un-grazed systems. Soil observations from these sites showed little effect from grazing practices, but larger soil carbon differences between farms. This may be due to spatial variation in SOC, making it difficult to measure and model, or due to controls of edaphic properties that make management moot. However, to further address these questions, model development will be needed to improve Manure-DNDC simulation of rotational grazing, as high stocking density grazing over short periods resulted in forage not re-growing sufficiently within the model. Furthermore, model simulations did not account for variation in interactions between livestock and soil given variability in field microclimates, perhaps requiring simulations that divide a single field into multiple paddocks to move towards more accurate evaluation of grazing management used in dairy operations in cool season pastures.

  4. Satellite Driven Estimation of Primary Productivity of Agroecosystems in India

    NASA Astrophysics Data System (ADS)

    Patel, N. R.; Dadhwal, V. K.; Agrawal, S.; Saha, S. K.

    2011-08-01

    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 (ɛ*) 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.

  5. Injury Profile SIMulator, a qualitative aggregative modelling framework to predict crop injury profile as a function of cropping practices, and the abiotic and biotic environment. I. Conceptual bases.

    PubMed

    Aubertot, Jean-Noël; Robin, Marie-Hélène

    2013-01-01

    The limitation of damage caused by pests (plant pathogens, weeds, and animal pests) in any agricultural crop requires integrated management strategies. Although significant efforts have been made to i) develop, and to a lesser extent ii) combine genetic, biological, cultural, physical and chemical control methods in Integrated Pest Management (IPM) strategies (vertical integration), there is a need for tools to help manage Injury Profiles (horizontal integration). Farmers design cropping systems according to their goals, knowledge, cognition and perception of socio-economic and technological drivers as well as their physical, biological, and chemical environment. In return, a given cropping system, in a given production situation will exhibit a unique injury profile, defined as a dynamic vector of the main injuries affecting the crop. This simple description of agroecosystems has been used to develop IPSIM (Injury Profile SIMulator), a modelling framework to predict injury profiles as a function of cropping practices, abiotic and biotic environment. Due to the tremendous complexity of agroecosystems, a simple holistic aggregative approach was chosen instead of attempting to couple detailed models. This paper describes the conceptual bases of IPSIM, an aggregative hierarchical framework and a method to help specify IPSIM for a given crop. A companion paper presents a proof of concept of the proposed approach for a single disease of a major crop (eyespot on wheat). In the future, IPSIM could be used as a tool to help design ex-ante IPM strategies at the field scale if coupled with a damage sub-model, and a multicriteria sub-model that assesses the social, environmental, and economic performances of simulated agroecosystems. In addition, IPSIM could also be used to help make diagnoses on commercial fields. It is important to point out that the presented concepts are not crop- or pest-specific and that IPSIM can be used on any crop.

  6. Impact of crop residue management on crop production and soil chemistry after seven years of crop rotation in temperate climate, loamy soils

    PubMed Central

    Hiel, Marie-Pierre; Barbieux, Sophie; Pierreux, Jérôme; Olivier, Claire; Lobet, Guillaume; Roisin, Christian; Garré, Sarah; Colinet, Gilles; Bodson, Bernard

    2018-01-01

    Society is increasingly demanding a more sustainable management of agro-ecosystems in a context of climate change and an ever growing global population. The fate of crop residues is one of the important management aspects under debate, since it represents an unneglectable quantity of organic matter which can be kept in or removed from the agro-ecosystem. The topic of residue management is not new, but the need for global conclusion on the impact of crop residue management on the agro-ecosystem linked to local pedo-climatic conditions has become apparent with an increasing amount of studies showing a diversity of conclusions. This study specifically focusses on temperate climate and loamy soil using a seven-year data set. Between 2008 and 2016, we compared four contrasting residue management strategies differing in the amount of crop residues returned to the soil (incorporation vs. exportation of residues) and in the type of tillage (reduced tillage (10 cm depth) vs. conventional tillage (ploughing at 25 cm depth)) in a field experiment. We assessed the impact of the crop residue management on crop production (three crops—winter wheat, faba bean and maize—cultivated over six cropping seasons), soil organic carbon content, nitrate (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${\\mathrm{NO}}_{3}^{-}$\\end{document}NO3−), phosphorus (P) and potassium (K) soil content and uptake by the crops. The main differences came primarily from the tillage practice and less from the restitution or removal of residues. All years and crops combined, conventional tillage resulted in a yield advantage of 3.4% as compared to reduced tillage, which can be partly explained by a lower germination rate observed under reduced tillage, especially during drier years. On average, only small differences were observed for total organic carbon (TOC) content of the soil, but reduced tillage resulted in a very clear stratification of TOC and also of P and K content as compared to conventional tillage. We observed no effect of residue management on the \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${\\mathrm{NO}}_{3}^{-}$\\end{document}NO3− content, since the effect of fertilization dominated the effect of residue management. To confirm the results and enhance early tendencies, we believe that the experiment should be followed up in the future to observe whether more consistent changes in the whole agro-ecosystem functioning are present on the long term when managing residues with contrasted strategies. PMID:29844983

  7. Malaria transmission risk variations derived from different agricultural practices in an irrigated area of northern Tanzania.

    PubMed

    Ijumba, J N; Mosha, F W; Lindsay, S W

    2002-03-01

    Malaria vector Anopheles and other mosquitoes (Diptera: Culicidae) were monitored for 12 months during 1994-95 in villages of Lower Moshi irrigation area (37 degrees 20' E, 3 degrees 21' S; approximately 700 m a.s.l.) south of Mount Kilimanjaro in northern Tanzania. Adult mosquito populations were sampled fortnightly by five methods: human bait collection indoors (18.00-06.00 hours) and outdoors (18.00-24.00 hours); from daytime resting-sites indoors and outdoors; by CDC light-traps over sleepers. Anopheles densities and rates of survival, anthropophily and malaria infection were compared between three villages representing different agro-ecosystems: irrigated sugarcane plantation; smallholder rice irrigation scheme, and savannah with subsistence crops. Respective study villages were Mvuleni (population 2200), Chekereni (population 3200) and Kisangasangeni (population approximately/= 1000), at least 7 km apart. Anopheles arabiensis Patton was found to be the principal malaria vector throughout the study area, with An. funestus Giles sensu lato of secondary importance in the sugarcane and savannah villages. Irrigated sugarcane cultivation resulted in water pooling, but this did not produce more vectors. Anopheles arabiensis densities averaged four-fold higher in the ricefield village, although their human blood-index was significantly less (48%) than in the sugarcane (68%) or savannah (66%) villages, despite similar proportions of humans and cows (ratio 1:1.1-1.4) as the main hosts at all sites. Parous rates, duration of the gonotrophic cycle and survival rates of An. arabiensis were similar in villages of all three agro-ecosystems. The potential risk of malaria, based on measurements of vectorial capacity of An. arabiensis and An.funestus combined, was four-fold higher in the ricefield village than in the sugarcane or savannah villages nearby. However, the more realistic estimate of malaria risk, based on entomological inoculation rates, indicated that exposure to infective vectors was 61-68% less for people in the ricefield village, due to the much lower sporozoite rate in An. arabiensis (ricefield 0.01%, sugarcane 0.1%, savannah 0.12%). This contrast was attributed to better socio-economic conditions of rice farmers, facilitating relatively more use of antimalarials and bednets for their families. Our findings show that, for a combination of reasons, the malaria challenge is lower for villagers associated with an irrigated rice-growing scheme (despite greater malaria vector potential), than for adjacent communities with other agro-ecosystems bringing less socio-economic benefits to health. This encourages the development of agro-irrigation schemes in African savannahs, provided that residents have ready access to antimalaria materials (i.e. effective antimalaria drugs and insecticidal bednets) that they may better afford for protection against the greater vectorial capacity of An. arabiensis from the ricefield agro-ecosystem.

  8. Projecting the bird community response resulting from the adoption of shelterbelt agroforestry practices in Eastern Nebraska

    Treesearch

    R. A., II Pierce; D. T. Farrand; W. B. Kurtz

    2001-01-01

    Evolving agricultural policies have influenced management practices within agroecosystems, impacting available habitats for many species of wildlife. Enhancing wildlife habitat has become an explicit objective of existing agricultural policy. Thus, there is renewed focus on field borders and the use of shelterbelt agroforestry systems to achieve conservation goals in...

  9. Taxonomy and distribution of phenazine-1-carboxylic acid-producing Pseudomonas spp. in the dryland agroecosystem of the Inland Pacific Northwest

    USDA-ARS?s Scientific Manuscript database

    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...

  10. The long term agroecosystem research network - shared research strategy

    Treesearch

    Jean L. Steiner; Timothy Strickland; Peter J.A. Kleinman; Kris Havstad; Thomas B. Moorman; M.Susan Moran; Phil Hellman; Ray B. Bryant; David Huggins; Greg McCarty

    2016-01-01

    While current weather patterns and rapidly accelerated changes in technology often focus attention on short-term trends in agriculture, the fundamental demands on modern agriculture to meet society food, feed, fuel and fiber production while providing the foundation for a healthy environment requires long-term perspective. The Long- Term Agroecoystem Research Network...

  11. Simulating Soil Organic Carbon Stock Changes in Agro-ecosystems using CQESTR, DayCent, and IPCC Tier 1 Methods

    USDA-ARS?s Scientific Manuscript database

    Models are often used to quantify how land use change and management impact soil organic carbon (SOC) stocks because it is often not feasible to use direct measuring methods. Because models are simplifications of reality, it is essential to compare model outputs with measured values to evaluate mode...

  12. Using fourier-transform mid-infrared spectroscopy to distinguish soil organic matter composition dynamics in aggregate fractions of two agroecosystems

    USDA-ARS?s Scientific Manuscript database

    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)...

  13. Plus C'est La Meme Chose? Questioning Crop Diversification as a Response to Agricultural Deregulation in Saskatchewan, Canada

    ERIC Educational Resources Information Center

    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…

  14. The Effect of Elevated CO2 and O3 on Soil Nitrogen Inputs and Losses in a Soybean Agroecosystem in Illinois

    USDA-ARS?s Scientific Manuscript database

    It has been found that elevated atmospheric carbon dioxide (eCO2) and tropospheric ozone (eO3) affect belowground microbial processes, including N transformations, through plant-mediated changes. Conversely, changes in soil organic carbon sequestration and plant biomass production are constrained by...

  15. In vitro and in vivo evaluation of cypermethrin, amitraz, and piperonyl butoxide mixtures for the control of resistant Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) in the Mexican tropics

    USDA-ARS?s Scientific Manuscript database

    The southern cattle fever tick, Rhipicephalus (Boophilus) microplus (Canestrini), is a haematophagous arachnid (Acari: Ixodidae) recognized globally as an economically important ectoparasite of cattle in tropical and subtropical agroecosystems. Populations of this invasive tick species around the wo...

  16. Impacts of elevated CO2 concentration on the productivity and surface energy budget of the soybean and maize agroecosystem in the Midwest US

    USDA-ARS?s Scientific Manuscript database

    The physiological response of vegetation to increasing atmospheric carbon dioxide concentration ([CO2]) modifies productivity and surface energy and water fluxes. Quantifying this response is required for assessments of future climate change. Many global climate models account for this response; how...

  17. FT-IR and C-13 NMR analysis of soil humic fractions from a long term cropping systems study

    USDA-ARS?s Scientific Manuscript database

    Increased knowledge of humic fractions is important due to its involvement in many soil ecosystem processes. Soil humic acid (HA) and fulvic acid (FA) from a nine-year agroecosystem study with different tillage, cropping system, and N source treatments were characterized using FT-IR andsolid-state ...

  18. Higher flexibility in input N:P ratios results in more balanced phosphorus budgets in two long-term experimental agroecosystems

    USDA-ARS?s Scientific Manuscript database

    Inefficient phosphorus (P) use in intensive agriculture is common in both organic and conventional systems, resulting in P overapplication and soil P build-up. Increasing crop P removal and P recycling within farming systems (e.g., via cover crops) and reducing P inputs can improve farm P balances. ...

  19. Impacts of crop sequence and minimum and no-till cropping systems on soil carbon stocks in south-central North Dakota, USA

    USDA-ARS?s Scientific Manuscript database

    Increased emphasis has been placed on developing agroecosystems that are inherently resistant and resilient to external stressors, yet are highly productive, economically competitive, and environmentally benign. As part of a long-term study to evaluate effects of crop sequence and tillage on crop yi...

  20. The effects of drought and herbivory on plant–herbivore interactions across 16 soybean genotypes in a field experiment

    USDA-ARS?s Scientific Manuscript database

    As the Earth’s climate continues to change, drought and insect population outbreaks are predicted to increase in many parts of the world. It is therefore important to understand how changes in such abiotic and biotic stressors might impact agroecosystems. 16 soybean genotypes were tested in a field ...

  1. First report of Fusarium graminearum, F. asiaticum and F. cortaderiae as head blight pathogens of annual ryegrass in Brazil

    USDA-ARS?s Scientific Manuscript database

    Members of the Fusarium graminearum species complex (FGSC) cause Fusarium head blight (FHB) of small grains and several grasses, including annual ryegrass (Lolium multiflorum Lam.), an important forage crop, but also a common weed in wheat, rice and maize agroecosystem in southern Brazil. Although i...

  2. RNAi knockdown of acetyl-CoA gene eliminates jinggangmycin-enhanced reproduction and population growth in the brown planthopper, Nilaparfata lugens

    USDA-ARS?s Scientific Manuscript database

    A major challenge in ecology lies in understanding the coexistence of intraguild species, well documented at the organismal level, but not at the molecular level. This study focused on the effects of the antibiotic, jinggangmycin (JGM), a fungicide widely used in Asian rice agroecosystems, on reprod...

  3. Soil enzyme activities during the 2011 Texas record drought/heat wave and implications to biogeochemical cycling and organic matter dynamics

    USDA-ARS?s Scientific Manuscript database

    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,...

  4. The Spatially-Distributed Agroecosystem-Watershed (Ages-W) Hydrologic/Water Quality (H/WQ) model for assessment of conservation effects

    USDA-ARS?s Scientific Manuscript database

    AgroEcoSystem-Watershed (AgES-W) is a modular, Java-based spatially distributed model which implements hydrologic/water quality (H/WQ) simulation components under the Object Modeling System (OMS3) environmental modeling framework. AgES-W has recently been enhanced with the addition of nitrogen (N) a...

  5. Effects of native perennial vegetation buffer strips on dissolved organic carbon in surface runoff from an agricultural landscape

    Treesearch

    Tomorra E. Smith; Randall K. Kolka; Xiaobo Zhou; Matthew J. Helmers; Richard M. Cruse; Mark D. Tomer

    2014-01-01

    Dissolved organic carbon (DOC) constitutes a small yet important part of a watershed's carbon budget because it is mobile and biologically active. Agricultural conservation practices such as native perennial vegetation (NPV) strips will influence carbon cycling of an upland agroecosystem, and could affect how much DOC enters streams in runoff, potentially...

  6. Natural enemy impact on the invasive brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), in organic agroecosystems: A regional assessment

    USDA-ARS?s Scientific Manuscript database

    Understanding natural enemy impacts on the invasive brown marmorated stink bug, Halyomorpha halys (Stål), gives insight into the population dynamics of this invasive pest and the potential for biological control. This two-year study provides a broad-scale assessment of mortality factors affecting s...

  7. Pesticide use within a pollinator-dependent crop has negative effects on the abundance and species richness of sweat bees, Lasioglossum spp., and on bumble bee colony growth.

    USDA-ARS?s Scientific Manuscript database

    Pesticides are implicated in current bee declines. Wild bees that nest or forage within agroecosystems may be exposed to numerous pesticides applied throughout their life cycles, with potential additive or synergistic effects. In pollinator-dependent crops, pesticides may reduce bee populations, cre...

  8. 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

    USDA-ARS?s Scientific Manuscript database

    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 ...

  9. Comparative analyses of measured evapotranspiration for various land surfaces

    Treesearch

    Suat Irmak

    2016-01-01

    There is a significant lack of continuously measured ET data for multiple land surfaces in the same area to be able to make comparisons of water use rates of different agroecosystems. This research presentation will provide continuous evapotranspiration and other surface energy balance variables measured above multiple land use and management practices.

  10. Report on Progress Toward Security and Stability in Afghanistan

    DTIC Science & Technology

    2013-11-01

    administered by the World Bank; contributors are Australia ($5.9 million), Finland ($2.5 million) and the United States ($50 million). Window B is...workshops for female extension personnel, launched on- farm grain storage trials, and conducted training on agro-ecosystem observation and analysis...Upcoming training will focus on wheat and vegetable production, marketing, post-harvest storage, farm financial management, and participatory

  11. Development of vegetation based soil quality indices for mineralized terrane in arid and semi-arid regions

    Treesearch

    S. W. Blecker; L. L. Stillings; M. C. Amacher; J. A. Ippolito; N. M. DeCrappeo

    2012-01-01

    Soil quality indices (SQIs) are often management driven and attempt to describe key relationships between above- and below-ground parameters. In terrestrial systems, indices that were initially developed and modified for agroecosystems have been applied to non-agricultural systems in increasing number. We develop an SQI in arid and semi-arid ecosystems of the Western...

  12. Long-term agroecosystem research in the Central Mississippi River Basin: dissolved nitrogen and phosphorus transport in a high-runoff-potential watershed

    USDA-ARS?s Scientific Manuscript database

    Long-term nutrient monitoring data from agricultural watersheds are needed to determine if efforts to reduce nutrient transport from crop and pasture land have been effective. The objectives of this study were to: 1) summarize dissolved ammonium-N (NH4-N), nitrate-N (NO3-N), and orthophosphate-P (PO...

  13. Linking a Germplasm Collection of the Cover Crop Hairy Vetch (Vicia villosa Roth) to Traits Related to Improved Nitrogen Fixation

    USDA-ARS?s Scientific Manuscript database

    Hairy vetch is used as a leguminous cover crop throughout the United States providing important ecosystem services in agro-ecosystems (Abdul-Baki et al., 2002; Mohler and Teasdale, 1993; Puget and Drinkwater, 2001; Seo et al., 2006; Stute and Posner, 1995). Many traits found in hairy vetch have pro...

  14. Increased Productivity of a Cover Crop Mixture Is Not Associated with Enhanced Agroecosystem Services

    PubMed Central

    Smith, Richard G.; Atwood, Lesley W.; Warren, Nicholas D.

    2014-01-01

    Cover crops provide a variety of important agroecological services within cropping systems. Typically these crops are grown as monocultures or simple graminoid-legume bicultures; however, ecological theory and empirical evidence suggest that agroecosystem services could be enhanced by growing cover crops in species-rich mixtures. We examined cover crop productivity, weed suppression, stability, and carryover effects to a subsequent cash crop in an experiment involving a five-species annual cover crop mixture and the component species grown as monocultures in SE New Hampshire, USA in 2011 and 2012. The mean land equivalent ratio (LER) for the mixture exceeded 1.0 in both years, indicating that the mixture over-yielded relative to the monocultures. Despite the apparent over-yielding in the mixture, we observed no enhancement in weed suppression, biomass stability, or productivity of a subsequent oat (Avena sativa L.) cash crop when compared to the best monoculture component crop. These data are some of the first to include application of the LER to an analysis of a cover crop mixture and contribute to the growing literature on the agroecological effects of cover crop diversity in cropping systems. PMID:24847902

  15. Increased Use of No-till Cropping Systems Improves Stream Ecosystem Quality

    NASA Astrophysics Data System (ADS)

    Yates, A. G.; Bailey, R. C.; Schwindt, J. A.

    2005-05-01

    Release of sediments to streams from tilled lands has been a significant stressor to streams in agro-ecosystems for decades and has been shown to impact aquatic biota in a variety of ways. To limit soil erosion from cultivated lands, conservation tillage techniques, including the use of no-till systems, have been developed and widely adopted throughout the region. However, there haves been no tests of the effects of no-till systems on stream quality at a watershed scale. We measured habitat and water quality and sampled the benthic macroinvertebrate (BMI) and fish communities in 32 small (100-1400 ha) subwatersheds along a gradient of the proportion of land under no-till cropping systems to determine relationships between the use of no-till and stream quality. Our results demonstrate that with increasing proportions of no-till, habitat scores improve, the quantities of sediment and sediment associated stressors in the water decline, the BMI community exhibits reduced dominance by Oligocheata and Sphaeriidae, as well as improved Family Biotic Index (FBI) scores, and fish species richness increases. We concluded that increased use of no-till cropping systems by farmers does contribute to improved quality of streams in agro-ecosystems.

  16. Biogeochemical cycling in Rice Agroecosystems Resulting From Water and Si management: Implications for As abatement and Sustainable Rice Production

    NASA Astrophysics Data System (ADS)

    Seyfferth, A.; Limmer, M. A.; Amaral, D.; Teasley, W.

    2017-12-01

    Flooded rice agroecosystems favor geochemical conditions that mobilize soil-bound arsenic (As) and produce methane (CH4). These negative outcomes of flooded rice may lead to As exposure upon As-laden rice grain consumption and enhanced greenhouse gas emissions. Periodic draining of fields (e.g., alternate wetting and drying) is effective at minimizing these negative outcomes, but may reduce rice yield, increase toxic Cd in grain, and increase nitrous oxide (N2O) emissions. Because 3 of the 4 dominant chemical form of As in flooded paddy soil share the efficient Si uptake pathway, increasing plant-available Si can decrease toxic As in grain and boost yield, particularly when plants are stressed with As. We used combined pot and field studies to examine the biogeochemical cycling of As, Fe, Si, and C when plants are grown with water and/or Si management, the latter of which under both low and high As conditions. We show that increasing plant-available Si can be used alone or in conjunction with water management to improve rice yields depending on the edaphic conditions. These processes and findings will be discussed in the larger context of global food security.

  17. The Hawaii Protocol for Scientific Monitoring of Coffee Berry Borer: a Model for Coffee Agroecosystems Worldwide

    PubMed Central

    Johnson, Melissa Anne; Hollingsworth, Robert; Fortna, Samuel; Aristizábal, Luis F.; Manoukis, Nicholas C.

    2018-01-01

    Coffee berry borer (CBB) is the most devastating insect pest for coffee crops worldwide. We developed a scientific monitoring protocol that is aimed at capturing and quantifying the dynamics and impact of this invasive insect pest as well as the development of its host plant across a heterogeneous landscape. The cornerstone of this comprehensive monitoring system is timely georeferenced data collection on CBB movement, coffee berry infestation, mortality by the fungus Beauveria bassiana, and coffee plant phenology via a mobile electronic data recording application. This electronic data collection system allows field records to be georeferenced through built-in global positioning systems, and is backed by a network of weather stations and records of farm management practices. Comprehensive monitoring of CBB and host plant dynamics is an essential part of an area-wide project in Hawaii to aggregate landscape-level data for research to improve management practices. Coffee agroecosystems in other parts of the world that experience highly variable environmental and socioeconomic factors will also benefit from implementing this protocol, in that it will drive the development of customized integrated pest management (IPM) to manage CBB populations. PMID:29608152

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

    PubMed

    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.

  19. A modelling methodology to assess the effect of insect pest control on agro-ecosystems.

    PubMed

    Wan, Nian-Feng; Ji, Xiang-Yun; Jiang, Jie-Xian; Li, Bo

    2015-04-23

    The extensive use of chemical pesticides for pest management in agricultural systems can entail risks to the complex ecosystems consisting of economic, ecological and social subsystems. To analyze the negative and positive effects of external or internal disturbances on complex ecosystems, we proposed an ecological two-sidedness approach which has been applied to the design of pest-controlling strategies for pesticide pollution management. However, catastrophe theory has not been initially applied to this approach. Thus, we used an approach of integrating ecological two-sidedness with a multi-criterion evaluation method of catastrophe theory to analyze the complexity of agro-ecosystems disturbed by the insecticides and screen out the best insect pest-controlling strategy in cabbage production. The results showed that the order of the values of evaluation index (RCC/CP) for three strategies in cabbage production was "applying frequency vibration lamps and environment-friendly insecticides 8 times" (0.80) < "applying trap devices and environment-friendly insecticides 9 times" (0.83) < "applying common insecticides 14 times" (1.08). The treatment "applying frequency vibration lamps and environment-friendly insecticides 8 times" was considered as the best insect pest-controlling strategy in cabbage production in Shanghai, China.

  20. Soil Fungal Resources in Annual Cropping Systems and Their Potential for Management

    PubMed Central

    Esmaeili Taheri, Ahmad; Bainard, Luke D.; Yang, Chao; Navarro-Borrell, Adriana; Hamel, Chantal

    2014-01-01

    Soil fungi are a critical component of agroecosystems and provide ecological services that impact the production of food and bioproducts. Effective management of fungal resources is essential to optimize the productivity and sustainability of agricultural ecosystems. In this review, we (i) highlight the functional groups of fungi that play key roles in agricultural ecosystems, (ii) examine the influence of agronomic practices on these fungi, and (iii) propose ways to improve the management and contribution of soil fungi to annual cropping systems. Many of these key soil fungal organisms (i.e., arbuscular mycorrhizal fungi and fungal root endophytes) interact directly with plants and are determinants of the efficiency of agroecosystems. In turn, plants largely control rhizosphere fungi through the production of carbon and energy rich compounds and of bioactive phytochemicals, making them a powerful tool for the management of soil fungal diversity in agriculture. The use of crop rotations and selection of optimal plant genotypes can be used to improve soil biodiversity and promote beneficial soil fungi. In addition, other agronomic practices (e.g., no-till, microbial inoculants, and biochemical amendments) can be used to enhance the effect of beneficial fungi and increase the health and productivity of cultivated soils. PMID:25247177

  1. The Hawaii Protocol for Scientific Monitoring of Coffee Berry Borer: a Model for Coffee Agroecosystems Worldwide.

    PubMed

    Johnson, Melissa Anne; Hollingsworth, Robert; Fortna, Samuel; Aristizábal, Luis F; Manoukis, Nicholas C

    2018-03-19

    Coffee berry borer (CBB) is the most devastating insect pest for coffee crops worldwide. We developed a scientific monitoring protocol that is aimed at capturing and quantifying the dynamics and impact of this invasive insect pest as well as the development of its host plant across a heterogeneous landscape. The cornerstone of this comprehensive monitoring system is timely georeferenced data collection on CBB movement, coffee berry infestation, mortality by the fungus Beauveria bassiana, and coffee plant phenology via a mobile electronic data recording application. This electronic data collection system allows field records to be georeferenced through built-in global positioning systems, and is backed by a network of weather stations and records of farm management practices. Comprehensive monitoring of CBB and host plant dynamics is an essential part of an area-wide project in Hawaii to aggregate landscape-level data for research to improve management practices. Coffee agroecosystems in other parts of the world that experience highly variable environmental and socioeconomic factors will also benefit from implementing this protocol, in that it will drive the development of customized integrated pest management (IPM) to manage CBB populations.

  2. A modelling methodology to assess the effect of insect pest control on agro-ecosystems

    PubMed Central

    Wan, Nian-Feng; Ji, Xiang-Yun; Jiang, Jie-Xian; Li, Bo

    2015-01-01

    The extensive use of chemical pesticides for pest management in agricultural systems can entail risks to the complex ecosystems consisting of economic, ecological and social subsystems. To analyze the negative and positive effects of external or internal disturbances on complex ecosystems, we proposed an ecological two-sidedness approach which has been applied to the design of pest-controlling strategies for pesticide pollution management. However, catastrophe theory has not been initially applied to this approach. Thus, we used an approach of integrating ecological two-sidedness with a multi-criterion evaluation method of catastrophe theory to analyze the complexity of agro-ecosystems disturbed by the insecticides and screen out the best insect pest-controlling strategy in cabbage production. The results showed that the order of the values of evaluation index (RCC/CP) for three strategies in cabbage production was “applying frequency vibration lamps and environment-friendly insecticides 8 times” (0.80) < “applying trap devices and environment-friendly insecticides 9 times” (0.83) < “applying common insecticides 14 times” (1.08). The treatment “applying frequency vibration lamps and environment-friendly insecticides 8 times” was considered as the best insect pest-controlling strategy in cabbage production in Shanghai, China. PMID:25906199

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

    PubMed

    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.

  4. Long-term lunar stations: Some ecological considerations

    NASA Technical Reports Server (NTRS)

    Maguire, Bassett, Jr.; Scott, Kelly W.

    1992-01-01

    A major factor for long-term success of a lunar station is the ability to keep an agroecosystem functioning at a desirable, stable steady-state with ecological stability and reliability. Design for a long-lived extraterrestrial manned station must take into account interactions among its subsystems to insure that overall functionality is enhanced (or at least not compromised). Physical isolation of feed production, human living areas, recycling, and other systems may be straightforward, however, microbiological isolation will be very difficult. While it is possible to eliminate plant-associated microbiological communities by growing the plants asepticallly, it is not practical to keep plants germ-free on a large scale if humans are working with them. Ecological theory strongly suggests that some kinds of communities or organisms effectively increase the stability of ecosystems and will protect the plants from potential pathogens. A carefully designed and maintained (lunar-derived) soil can provide a variety of habitats for effective microbial buffers while adding structure to the agroecosystem. A soil can also increase ecosystem reliability through buffering otherwise large element and compound fluctuations (of nutrients, wastes, etc.) as well as buffering temperature level and atmosphere composition. We are doing experiments in ecological dynamics and attempting to extend the relevant theories.

  5. Life cycle of the corn-soybean agroecosystem for biobased production.

    PubMed

    Landis, Amy E; Miller, Shelie A; Theis, Thomas L

    2007-02-15

    Biobased product life cycle assessments (LCAs) have focused largely on energy (fossil fuel) usage and greenhouse gas emissions during the agriculture and production stages. This paper compiles a more comprehensive life cycle inventory (LCI) for use in future bioproduct LCAs that rely on corn or soybean crops as feedstocks. The inventory includes energy, C, N, P, major pesticides, and U.S. EPA criteria air pollutants that result from processes such as fertilizer production, energy production, and on-farm chemical and equipment use. Agroecosystem material flows were modeled using a combination of GREET (the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation model), a linear fractionation model that describes P biogeochemical cycling, and Monte Carlo Analysis. Results show that the dominant air emissions resulted from crop farming, fertilizers, and on-farm nitrogen flows (e.g., N20 and NO). Seed production and irrigation provided no more than 0.002% to any of the inventory emissions or energy flows and may be neglected in future LCAs of corn or soybeans as feedstocks from the U.S. Corn Belt. Lime contributes significantly (17% of total emissions) to air emissions and should not be neglected in bioproduct LCAs.

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

    PubMed Central

    Oruru, Marjorie Bonareri; Njeru, Ezekiel Mugendi

    2016-01-01

    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. PMID:26942194

  7. Fate of carbamazepine, its metabolites, and lamotrigine in soils irrigated with reclaimed wastewater: Sorption, leaching and plant uptake.

    PubMed

    Paz, Anat; Tadmor, Galit; Malchi, Tomer; Blotevogel, Jens; Borch, Thomas; Polubesova, Tamara; Chefetz, Benny

    2016-10-01

    Irrigation with reclaimed wastewater may result in the ubiquitous presence of pharmaceutical compounds (PCs) and their metabolites in the agroecosystem. In this study, we focused on two highly persistent anticonvulsant drugs, lamotrigine and carbamazepine and two of its metabolites (EP-CBZ and DiOH-CBZ), aiming to elucidate their behavior in agricultural ecosystem using batch and lysimeter experiments. Sorption of the studied compounds by soils was found to be governed mainly by the soil organic matter level. Sorption affinity of compounds to soils followed the order lamotrigine > carbamazepine > EP-CBZ > DiOH-CBZ. Sorption was reversible, and no competition between sorbates in bi-solute systems was observed. The results of the lysimeter studies were in accordance with batch experiment findings, demonstrating accumulation of lamotrigine and carbamazepine in top soil layers enriched with organic matter. Detection of carbamazepine and one of its metabolites in rain-fed wheat previously irrigated with reclaimed wastewater, indicates reversibility of their sorption, resulting in their potential leaching and their availability for plant uptake. This study demonstrates the long-term implication of introduction of PCs to the agroecosystem. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Microbial communities and soil fertility in flood irrigated orchards under different management systems in eastern spain

    NASA Astrophysics Data System (ADS)

    Morugán-Coronado, Alicia; García-Orenes, Fuensanta; Caravaca, Fuensanta; Roldán, Antonio

    2016-04-01

    Unsuitable land management such as the excessive use of herbicides can lead to a loss of soil fertility and a drastic reduction in the abundance of microbial populations and their functions related to nutrient cycling. Microbial communities are the most sensitive and rapid indicators of perturbations in agroecosystems. A field experiment was performed in an orange-trees orchard (Citrus sinensis) to assess the long-term effect of three different management systems on the soil microbial community biomass, structure and composition (phospholipid fatty acids (PLFAs) total, pattern, and abundance). The three agricultural systems assayed were established 30 years ago: herbicides (Glyphosate (N-(phosphonomethyl)glycine) with inorganic fertilizers (H), intensive ploughing and inorganic fertilizers (NPK 15%) (P) and organic farming (chipped pruned branches and weeds, manure from sheep and goats) (O). Nine soil samples were taken from each system. The results showed that the management practices including herbicides and intensive ploughing had similar results on soil microbial properties, while organic fertilization significantly increased microbial biomass, shifted the structure and composition of the soil microbial community, and stimulated microbial activity, when compared to inorganic fertilization systems; thus, enhancing the sustainability of this agroecosystem under semiarid conditions.

  9. Barriers to implementing climate resilient agricultural strategies: The case of crop diversification in the U.S. Corn Belt

    Treesearch

    Gabrielle E. Roesch-McNally; J.G. Arbuckle; John C. Tyndall

    2018-01-01

    Cropping system diversity can help build greater agroecosystem resilience by suppressing insect, weed, and disease pressures while also mitigating effects of extreme and more variable weather. Despite the potential benefits of cropping systems diversity, few farmers in the US Corn Belt use diverse rotations. This study examines factors that may influence farmers’...

  10. Long term acroecosystem research in the Southern Plains

    Treesearch

    Jean L. Steiner; Patrick J. Starks; Jurgen Garbrecht; Daniel Moriasi; Paul Bartholomew; Jim Neel; Kenneth E. Turner; Brian Northup

    2016-01-01

    The Southern Plains (SP) site of the Long Term Agroecosystem Research (LTAR) network is headquartered at the USDA-ARS Grazinglands Research Laboratory (GRL) in El Reno, Oklahoma. The GRL was established in 1948. A long-term watershed and climate research program was established in the Little Washita River Experimental Watershed (LWREW) in 1961 and in the Fort Cobb...

  11. A Comparison of ectoparasite infestation by chigger mite larvae (Acarina: Trombiculidae) on resident and migratory birds in Chiapas, Mexico illustrating a rapid visual assessment protocol

    Treesearch

    Thomas V. Dietsch

    2005-01-01

    This study presents a protocol developed to rapidly assess ectoparasite prevalence and intensity. Using this protocol during a mist-netting project in two different coffee agroecosystems in Chiapas, Mexico, data were collected on ectoparasitic chigger mite larvae (Acarina: Trombiculidae) found on resident and migratory birds. Surprisingly high infestation rates were...

  12. A Conceptual Framework for the Assessment of Multiple Functions of Agro-Ecosystems: A Case Study of Tras-os-Montes Olive Groves

    ERIC Educational Resources Information Center

    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…

  13. Long-term agroecosystem research in the Central Mississippi River Basin: hydrogeologic controls and crop management influence on nitrates in loess and fractured glacial till

    USDA-ARS?s Scientific Manuscript database

    Nitrogen (N) from agricultural activities has been suspected as a primary source of elevated ground water nitrate (NO3-N). The objective of this research was to assess the impact of common cropping systems on NO3-N levels for a glacial till aquifer underlying claypan soils in a predominantly agricul...

  14. Assessing the site-specific impacts of climate change on hydrology, soil erosion and crop yields in the Loess Plateau of China

    USDA-ARS?s Scientific Manuscript database

    Climate changes can have great impacts on fragile agro-ecosystems in the Loess Plateau of China, which is one of the most severely eroded regions in the world. The objective of this study is to assess the site-specific impacts of projected climate change scenarios for 2010-2039 on hydrology, soil l...

  15. Nitrogen and carbon dynamics in prairie vegetation strips across topographical gradients in mixed Central Iowa agroecosystems

    Treesearch

    Marlín Pérez-Suárez; Michael J. Castellano; Randall Kolka; Heidi Asbjornsen; Matthew Helmers

    2014-01-01

    Reductions of nitrogen (N) export from agricultural lands because of changes in specific N stocks andfluxes by incorporation of small amounts of prairie vegetation strips (PVS) are poorly understood. Theprimary objective of this study was to evaluate the effect of the presence and topographical position of PVSon soil and plant carbon (C) and N stocks relative to annual...

  16. A new species of myrmecophilous lady beetle in the genus Diomus (Coleoptera: Coccinellidae: Diomini) from Chiapas, Mexico that feeds on green coffee scale, Coccus viridis (Green) (Hemiptera: Coccidae)

    USDA-ARS?s Scientific Manuscript database

    A new species of myrmecophilous lady beetle in the genus Diomus (Coleoptera: Coccinellidae: Diomini) is described from a coffee agroecosystem in Chiapas, Mexico. The new species was found preying on the green coffee scale pest, Coccus viridis (Green), tended primarily by Azteca sericeasur Longino an...

  17. Use of Participatory Systems Dynamics Modelling to Generate User-Friendly Decision Support Systems for the Design of Management Policies for Complex Human-Environmental Systems: A Case Study from the Varied Socio-environmental Landscape of Guatemala

    NASA Astrophysics Data System (ADS)

    Malard, J. J.; Baig, A. I.; Carrera, J.; Mellini, L.; Pineda, P.; Monterroso, O.; Melgar-Quiñonez, H.; Adamowski, J. F.; Halbe, J.; Monardes, H.; Gálvez, J.

    2014-12-01

    The design of effective management policies for socioenvironmental systems requires the development of comprehensive, yet sufficiently simple, decision support systems (DSS) for policy makers. Guatemala is a particularly complex case, combining an enormous diversity of climates, geographies, and agroecosystems within a very small geographical scale. Although food insecurity levels are very high, indicating a generally inadequate management of the varied agroecosystems of the country, different regions have shown vastly different trends in food insecurity over the past decade, including between regions with similar geophysical and climatic characteristics and/or governmental programmes (e.g., agricultural support). These observations suggest two important points: firstly, that not merely environmental conditions but rather socio-environmental interactions play a crucial role in the successful management of human-environmental systems, and, secondly, that differences in the geophysical and climatic environments between the diverse regions significantly impact the success or failure of policies. This research uses participatory systems dynamic modelling (SDM) to build a DSS that allows local decision-makers to (1) determine the impact of current and potential policies on agroecosystem management and food security, and (2) design sustainable and resilient policies for the future. The use of participatory SDM offers several benefits, including the active involvement of the end recipients in the development of the model, greatly increasing its acceptability; the integration of physical (e.g., precipitation, crop yield) and social components in one model; adequacy for modelling long-term trends in response to particular policy decisions; and the inclusion of local stakeholder knowledge on system structure and trends through the participatory process. Preliminary results suggest that there is a set of common variables explaining the generally high levels of food insecurity in Guatemala (e.g., agricultural productivity), while others (e.g., land dynamics and access to water resources) are restricted to certain regions and have a relatively important weight in determining the success or failure of policies in these regions.

  18. Seasonal abundance of soil arthropods in relation to meteorological and edaphic factors in the agroecosystems of Faisalabad, Punjab, Pakistan

    NASA Astrophysics Data System (ADS)

    Shakir, Muhammad Mussadiq; Ahmed, Sohail

    2015-05-01

    Soil arthropods are an important component of agroecosystems, contributing significantly to their biodiversity and functioning. However, seasonal patterns, population dynamics, and significant roles of these soil arthropods in improvement of soil structures and functions are influenced by many factors. The objective of the current study was to investigate soil arthropod abundance in relation to a blend of meteorological and edaphic factors and to find out the difference in abundance among various crops (sugarcane, cotton, wheat, alfalfa fodder, and citrus orchards). The arthropod sampling was done by pitfall traps and Tullgren extractions on fortnightly intervals. Soil temperature and relative humidity were noted on the field sites while analysis for soil pH, organic matter, and soil moisture contents were done in the laboratory. The rainfall data was obtained from an observatory. Results showed that significant differences were found in soil arthropod abundance across different sampling months and crops. Out of total 13,673 soil arthropods sampled, 38 % belonged to Collembola, followed by 15 % Hymenoptera, 15 % Acarina, 11 % Myriapods, 6 % Coleoptera, 5 % Orthoptera, and 5 % Araneae. Mean abundance per sample was highest in summer months as compared to winter. Overall abundance per sample was significantly different between all crops ( p < 0.05). Cluster analysis revealed four categories of soil arthropods according to abundance, i.e., highly abundant (Collembola, Acarina, Myripoda, Hymenoptera), moderately abundant (Orthoptera, Aranae, Coleoptera), least abundant (Dermaptera, Hemiptera, Diptera), and rare (Blattaria, Isoptera, Diplura, Lepidoptera). Soil temperature and soil organic matter showed significant positive correlation with abundance, while relative humidity was significantly negatively correlated. Soil moisture and soil pH showed no significant correlations while no correlation was found with total rainfall. PCA analysis revealed that soil surface arthropods were the major contributors of variation in overall abundance in extreme temperature months while microarthropods in low-temperature months. CCA analysis revealed the occurrence of different arthropod groups in correspondence with different abiotic variables. Results are discussed in view of position of these arthropods as useful indicators under changing environmental conditions impacting agroecosystems in the study area.

  19. Can Managed Grazing be Part of Healthy Agroecosystems? Impacts of Various Systems on Soil Water and other Ecosystem Services

    NASA Astrophysics Data System (ADS)

    DeLonge, M. S.; Basche, A.; Gonzalez, J.

    2016-12-01

    Due to the vast extent of grazing lands, value of grassland ecosystems, and environmental impacts of the agricultural sector, it is becoming increasingly important to understand to what extent managed grazing can be part of healthy agroecosystems. For example, grazing systems can degrade soils, pollute water, and result in substantial direct and indirect animal emissions. On the other hand, well-managed grasslands can store more carbon, support more biodiversity, and require fewer inputs than croplands or other land uses. Systems analyses are needed to evaluate how much grazing management (e.g., altering stocking rate intensity or regime, integrating versus separating crops and livestock, adopting silvopasture techniques) can affect agroecosystem properties and farm viability. As a result of climate change and likely increases to rainfall variability, the effects of grazing systems on soil water properties are particularly important. The primary goal of this study is to use meta-analytic techniques to better understand how changes to grazing systems affect soil water properties, focusing on soil water infiltration rates. Another goal is to conduct a literature survey to assess how similar changes to grazing have influenced other ecosystem services (e.g., soil carbon, farm profitability) and to identify gaps in knowledge. To date, our meta-analysis includes over 100 paired comparisons (>30 studies) related to grazing. The analysis is a subset of a broader study of agroecological practices that to date includes >350 paired observations. Preliminary results point to significant variability, but suggest that integrating livestock into croplands decreases infiltration (12%), whereas other changings to grazing (decreasing stocking rates, moving from continuous to rotational grazing, or converting to a silvopasture system) can improve infiltration (by an average of 223% including all practices). Findings also suggest that removing livestock tends to increase infiltration rates over time. In cases where infiltration rates are negatively affected by grazing, soil conservation practices such as planting perennials or rotating crops) might mitigate those effects. However, the magnitude of these effects may depend on variables such as time since management change and rainfall regime.

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

    NASA Astrophysics Data System (ADS)

    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 about driving forces and stakeholder preference. Trade-offs among the various products and services produced by landscapes are required and finding the proper balance presents a continual challenge for policy-makers and land managers when it comes to placing best management practices in a watershed.

  1. Comparison of Historically Severe Droughts and the Vulnerability of Agroecosystems in Mid-Continent USA: Lessons Learned

    NASA Astrophysics Data System (ADS)

    Olson, C.; Rippey, B.

    2016-12-01

    Extreme climatic events, drought, flooding, severe storms, tropical cyclones and winter storms have cost the USA billions of dollars. Although among major natural disasters in the last 100 years, severe drought occurrences are lower in terms of discrete events than that for other extreme events, the average cost per drought event exceeds all but those of severe storms and tropical cyclones and has significantly impacted the US agroecosystems upon which much of the domestic and export food markets depend1. The impacts from the 2012, 1988, and 1950's droughts are compared with the effects on cropland in the Mid-Continent US. Drought severity in 2012 and in 1988 were similar in terms of economic agricultural loss, 40 and 31 billion in cost-adjusted dollars, respectively. The 2012 drought covered a geographic areal extent similar to that of an earlier drought in the 1950's; roughly 2/3 of the central USA was impacted. However, the 2012 drought developed relatively rapidly in less than a year whereas the drought of the 1950's was marked by multiple years of extreme heat and lack of precipitation. Each of these severe droughts has resulted in significant losses, but the 2012 drought, while costly, could have been a larger economic disaster had the same conditions occurred in the 1950's or 1988. Investment in new technology, improvements in irrigation efficiency and advanced drainage systems, targeted soil conservation practices, and flexibility to adapt to conditions have improved the resilience of agroecosystems to drought in the intervening years. Droughts continue to occur, so a better understanding of climate and available climate services along with sustained investment in new technology will improve drought tolerance. The recent establishment of USDA Regional Climate Hubs to translate and deliver science-based, region-specific information for individual natural resource managers will enable climate-smart decision-making. Implementation is now possible at scales appropriate to identify regional and potentially local vulnerabilities and rapidly assess needs and capabilities. Downscaled climate projections developed by USDA partners and tailored to regional needs will become essential tools for future drought resilience. 1. Data trends derived from www.ncdc.noaa.gov/billions/summary-stats

  2. Linking resilience theory and diffusion of innovations theory to understand the potential for perennials in the U.S. Corn Belt

    Treesearch

    Ryan C. Atwell; Lisa A. Schulte; Lynne M. Westphal

    2009-01-01

    In the last 200 yr, more than 80% of the land in the U.S. Corn Belt agro-ecosystem has been converted from natural perennial vegetation to intensive agricultural production of row crops. Despite research showing how re-integration of perennial vegetation, e.g., cover crops, pasture, riparian buffers, and restored wetlands, at strategic landscape positions can bolster...

  3. Gulf Atlantic Coastal Plain Long Term Agroecosystem Research site, Tifton, GA

    Treesearch

    Timothy Strickland; David D. Bosch; Dinku M. Endale; Thomas L. Potter

    2016-01-01

    The Gulf-Atlantic Coastal Plain (GACP) physiographic region is an important agricultural production area within the southeastern U.S. that extends from Delaware in the Northeast to the Gulf Coast of Texas. The region consists mainly of low-elevation flat to rolling terrain with numerous streams, abundant rainfall, a complex coastline, and many wetlands. The GACP Long ...

  4. Land Cover Land Use Change and Soil Organic Carbon under Climate Variability in the Semi-Arid West African Sahel (1960-2050)

    ERIC Educational Resources Information Center

    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…

  5. Diversity and structure of landraces of Agave grown for spirits under traditional agriculture: A comparison with wild populations of A. angustifolia (Agavaceae) and commercial plantations of A. tequilana.

    PubMed

    Vargas-Ponce, Ofelia; Zizumbo-Villarreal, Daniel; Martínez-Castillo, Jaime; Coello-Coello, Julián; Colunga-Garcíamarín, Patricia

    2009-02-01

    Traditional farming communities frequently maintain high levels of agrobiodiversity, so understanding their agricultural practices is a priority for biodiversity conservation. The cultural origin of agave spirits (mezcals) from west-central Mexico is in the southern part of the state of Jalisco where traditional farmers cultivate more than 20 landraces of Agave angustifolia Haw. in agroecosystems that include in situ management of wild populations. These systems, rooted in a 9000-year-old tradition of using agaves as food in Mesoamerica, are endangered by the expansion of commercial monoculture plantations of the blue agave variety (A. tequilana Weber var. Azul), the only agave certified for sale as tequila, the best-known mezcal. Using intersimple sequence repeats and Bayesian estimators of diversity and structure, we found that A. angustifolia traditional landraces had a genetic diversity (H(BT) = 0.442) similar to its wild populations (H(BT) = 0.428) and a higher genetic structure ((B) = 0.405; (B) =0. 212). In contrast, the genetic diversity in the blue agave commercial system (H(B) = 0.118) was 73% lower. Changes to agave spirits certification laws to allow the conservation of current genetic, ecological and cultural diversity can play a key role in the preservation of the traditional agroecosystems.

  6. Identifying the characteristic of SundaParahiyangan landscape for a model of sustainable agricultural landscape

    NASA Astrophysics Data System (ADS)

    Dahlan, M. Z.; Nurhayati, H. S. A.; Mugnisjah, W. Q.

    2017-10-01

    This study was an explorative study of the various forms of traditional ecological knowledge (TEK) of Sundanese people in the context of sustainable agriculture. The qualitative method was used to identify SundaParahiyangan landscape by using Rapid Participatory Rural Appraisal throughsemi-structured interviews, focus group discussions, and field survey. The Landscape Characteristic Assessment and Community Sustainability Assessment were used to analyze the characteristic of landscape to achieve the sustainable agricultural landscape criteria proposed by US Department of Agriculture. The results revealed that the SundaParahiyangan agricultural landscape has a unique characteristic as a result of the long-term adaptation of agricultural society to theirlandscape through a learning process for generations. In general, this character was reflected in the typical of Sundanese’s agroecosystems such as forest garden, mixed garden, paddy field, and home garden. In addition, concept of kabuyutan is one of the TEKs related to understanding and utilization of landscape has been adapted on revitalizing the role of landscape surrounding the agroecosystem as the buffer zone by calculating and designating protected areas. To support the sustainability of production area, integrated practices of agroforestry with low-external-input and sustainable agriculture (LEISA) system can be applied in utilizing and managing agricultural resources.

  7. Evolution of pathogenicity traits in the apple scab fungal pathogen in response to the domestication of its host

    PubMed Central

    Lê Van, Amandine; Gladieux, Pierre; Lemaire, Christophe; Cornille, Amandine; Giraud, Tatiana; Durel, Charles-Eric; Caffier, Valérie; Le Cam, Bruno

    2012-01-01

    Understanding how pathogens emerge is essential to bring disease-causing agents under durable human control. Here, we used cross-pathogenicity tests to investigate the changes in life-history traits of the fungal pathogen Venturia inaequalis associated with host-tracking during the domestication of apple and subsequent host-range expansion on the wild European crabapple (Malus sylvestris). Pathogenicity of 40 isolates collected in wild and domesticated ecosystems was assessed on the domesticated apple, its Central Asian main progenitor (M. sieversii) and M. sylvestris. Isolates from wild habitats in the centre of origin of the crop were not pathogenic on the domesticated apple and less aggressive than other isolates on their host of origin. Isolates from the agro-ecosystem in Central Asia infected a higher proportion of plants with higher aggressiveness, on both the domesticated host and its progenitor. Isolates from the European crabapple were still able to cause disease on other species but were less aggressive and less frequently virulent on these hosts than their endemic populations. Our results suggest that the domestication of apple was associated with the acquisition of virulence in the pathogen following host-tracking. The spread of the disease in the agro-ecosystem would also have been accompanied by an increase in overall pathogenicity. PMID:23144656

  8. Nitrous Oxide and Methane Fluxes in Responses to Conservation Management across Cropping Systems in Asia from a Data-Model Integration Perspective

    NASA Astrophysics Data System (ADS)

    Ren, W.; Huang, Y.; Tao, B.; Zhu, X.; Tian, H.

    2017-12-01

    The agriculture sector is estimated to be responsible for 12% of the total greenhouse gas emissions, particularly for 52% of CH4 and 84% of N2O. It has been predicted that the world population would reach 9.7 billion by 2050 and require a 60 percent increase in total agricultural production above the level of 2005-07, which would potentially further boost greenhouse gas emissions from agroecosystems. The growing concerns over food security and rapid rate of global warming necessitates the development of conservation management (or climate-smart soil management) that can ensure high crop yield and meanwhile markedly enhance soil sequestration and reduce GHG emissions. In this study, we synthesize multi-source datasets and apply an improved agroecosystem model to quantitatively investigate the dynamics of CH4 and N2O fluxes as influenced by conservation management practices in cropping systems of Asia (such as wheat, corn, and rice) for exploring the potential of those practices to mitigate and adapt to climate change. Our preliminary results suggest that the conservation tillage (e.g., reduced and no tillage) can largely suppress CH4 emissions from Asia's rice paddies, although they, to some extent, may stimulate NO2 emissions, comparing with the conventional tillage.

  9. Relationships between primary production and crop yields in semi-arid and arid irrigated agro-ecosystems

    NASA Astrophysics Data System (ADS)

    Jaafar, H. H.; Ahmad, F. A.

    2015-04-01

    In semi-arid areas within the MENA region, food security problems are the main problematic imposed. Remote sensing can be a promising too early diagnose food shortages and further prevent the population from famine risks. This study is aimed at examining the possibility of forecasting yield before harvest from remotely sensed MODIS-derived Enhanced Vegetation Index (EVI), Net photosynthesis (net PSN), and Gross Primary Production (GPP) in semi-arid and arid irrigated agro-ecosystems within the conflict affected country of Syria. Relationships between summer yield and remotely sensed indices were derived and analyzed. Simple regression spatially-based models were developed to predict summer crop production. The validation of these models was tested during conflict years. A significant correlation (p<0.05) was found between summer crop yield and EVI, GPP and net PSN. Results indicate the efficiency of remotely sensed-based models in predicting summer yield, mostly for cotton yields and vegetables. Cumulative summer EVI-based model can predict summer crop yield during crisis period, with deviation less than 20% where vegetables are the major yield. This approach prompts to an early assessment of food shortages and lead to a real time management and decision making, especially in periods of crisis such as wars and drought.

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

    PubMed

    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.

  11. Biodegradation of isoproturon by Pseudoxanthomonas sp. isolated from herbicide-treated wheat fields of Tarai agro-ecosystem, Pantnagar.

    PubMed

    Giri, Krishna; Pandey, Shailseh; Kumar, Rajesh; Rai, J P N

    2016-12-01

    A gram-negative, rod-shaped, isoproturon (IPU) utilizing bacterium was isolated from herbicide-applied wheat fields of Tarai agro-ecosystem, Pantnagar. The phylogenetic sequence analysis based on 16S rRNA sequence revealed that the isolate could be a distinct species within the genus Pseudomonas. The isolate was a close relative of Pseudoxanthomonas japonensis (95 % similarity) and designated as K2. The bacterial isolate showed positive reaction for oxidase, catalase, and 20 carbohydrates using KB009 Part A and B HiCarbohydrate™ Kit. Degradation experiments were conducted using 200 mg l -1 initial IPU as a source of carbon at different pH and temperatures. Maximum IPU degradation by K2 was observed at pH 7.0 and 30 °C, while least degradation at 6.5 pH and 25 °C. Addition of dextrose along with IPU as an auxiliary carbon source increased IPU degradation by 4.72 %, as compared to the IPU degradation without dextrose under optimum conditions. 4-isopropylaniline was detected as a degradation by-product in the medium. The present study demonstrated the IPU metabolizing capacity of a novel bacterial isolate K2 that can be a better choice for the remediation of IPU-contaminated sites.

  12. Soil redistribution and nutrient delivery in a Mediterranean rain-fed agro-ecosystem with different crops and management: environmental and economic aspects

    NASA Astrophysics Data System (ADS)

    López-Vicente, Manuel; Álvarez, Sara

    2017-04-01

    Mediterranean agro-ecosystems are characterised by fragmented fields and patched vegetation. This shape governs the spatial patterns of water, soil and nutrient redistribution. Rainfall parameters, human infrastructures, crop management, support practices, and land use changes (set aside crops, land abandonment) control the magnitude of these processes. Under rain-fed water supply conditions, runoff generation and soil water content are two important factors in determining crop yield. Soil erosion and nutrient delivery are two of the factors which limit crop yield and thus, the gross earning of the landowner. In hilly landscapes, farmers usually supply extra soil to fill in the ephemeral gullies, and nutrient replenishment with fertilizers is a common practice. The aim of this study is to evaluate the environmental (runoff yield, soil erosion and nutrient delivery) and economic (replenishment of soil and nutrient losses with new soil and fertilizers) consequences of different conventional and conservative practices (fallow/crop rotation, cover crops, land abandonment, buffer strips) in a Mediterranean rain-fed agro-ecosystem (27 ha) with vineyards, cereal crops, cultivated and abandoned olive orchards, several trails and patches of natural vegetation. The five winter cereal fields (wheat and barley) follow fallow/crop rotation. The four vineyards are devoted to the Garnacha variety: one planted in 2007 with white wine grapes, and three planted in 2008 with red wine grapes. The inter-crop strips are managed with a mixture of plant species as cover crop (CC), including: i) spontaneous vegetation, and ii) plantation of common sainfoin (Onobrychis viciifolia). The maintenance of the CC includes one mowing pass at the end of spring, between May and June. The appearance and development of ephemeral gullies and the deposition of soil at the bottom of the hillslope are two of the main concerns of the landowners. In some places, the accumulation of soil complicates grape harvest operations with machinery, forcing manual labour. A total of 222 soil samples were collected in 74 points, and some physical (coarse fragments, effective volume, bulk density, texture, infiltration, etc.) and chemical (soil organic carbon - SOC, total nitrogen, phosphorous and potassium) parameters analysed. The highest values of SOC and TN were found in the forestry (4.64% and 0.198%) and abandoned soils (2.96% and 0.132%), whereas the highest values of TP appeared in the cereal, olive and vineyards (458.4, 458.0 and 440.3 mg / kg P). The highest content of TK appeared in the vineyards (1979.1 mg / kg K), especially in the grapevine strips (2188.3 mg / kg K), due to the fertilizer supply. In order to assess the water, soil and nutrient budgets, four buried sediment traps were installed near the bottom and before reaching the depositional-prone area. The upslope contributing areas of the traps are not nested. Monitoring the magnitude of runoff and sediment yield and the chemical composition of the collected samples allowed calculating the economic cost of water, soil and nutrient losses. The results of this study have implications for other rain-fed productive agro-ecosystems as well as where conservative practices may reduce the economic cost of farmland management.

  13. Dataset on the regulation of banana weevil abundance and corm damage associated with plant richness and the ground-dwelling arthropods' food web.

    PubMed

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

    2017-12-01

    The data presented in this article are related to the research article entitled "Plant richness enhances banana weevil regulation in a tropical agroecosystem by affecting a multitrophic food web " [1]. It provides information about plant species richness, weevil corm damage and the abundance of different arthropod groups, including the banana weevil and its potential natural enemies and alternative preys.

  14. Agricultural Carbon Sinks

    NASA Astrophysics Data System (ADS)

    Horwath, W. R.; Lal, R.

    2016-12-01

    Agriculture is a source or sink of greenhouse gases depending on land use and management. Diverse activities of agroecosystems include croplands, grazing lands, forestlands, integration among these three land use systems (e.g., agroforestry, agro-pastoral, silvo-pastoral, and agro-silvo-pastoral systems), and urban and degraded lands. Conversion of natural to agroecosystems leads to decline in soil organic carbon (SOC) pool because of reduction in input of biomass-C (C­i) and increase in losses (Cl) by mineralization, erosion and leaching (Cil) through changes in micro-climate, components of the hydrologic cycle and energy budgets, and alterations in biogeochemical cycles. Historic loss from soils of agroecosystems may range from 25 to 50% in temperate regions and 50 to 75% in the tropics. The magnitude of SOC depletion is aggravated by soil degradation caused by erosion, salinization, etc. Thus, there exists a soil/ecosystem C sink which can be refilled through best management practices which create a positive C budget (Ci>Cl) and lead to recarbonization. The average rate of SOC sequestration is 0-250 kg C/ha•yr for warm and dry regions vs. 250-500 kgC/ha•yr for cool and moist climates. The potential of C sequestration is estimated at 0.4-1.2 Pg C/yr for cropland; 0.3-0.5 PgC/yr savanna and grasslands; 1.2-1.4 PgC/yr for afforestation, agroforestry, forest succession and peatlands; 0.2-0.5 PgC/yr for forest plantations; 0.3-0.7 PgC/yr for restoration of salt affected soils, and 0.2-0.7 PgC/yr for erosion and desertification control. There is an emission-avoidance by enhancing eco-efficiency of farm operations (e.g., plowing, irrigation, and input of herbicides and pesticides). These strategies are in accord with the implementation of "4 per Thousand" initiative proposed at the COP21 and COP22 Summits in Paris and Marrakech, respectively. Payments to land managers for ecosystem services, based on societal value of soil C, can promote adoption of BMPs, advance Sustainable Development Goals of the U.N., and achieve food security while improving the environment. Recarbonization of soil and ecosystems is a win-win option, and a bridge to the future until low-C or no-C fuel sources take effect.

  15. Impact of land use on soil organic carbon distribution in toposequences of the Central Rif, Morocco

    NASA Astrophysics Data System (ADS)

    Mesrar, Haytam; Sadiki, Abdelhamid; Faleh, Ali; Quijano, Laura; Gaspar, Leticia; Navas, Ana

    2017-04-01

    Mediterranean mountain agroecosystems are sensitive areas to soil degradation mainly due to erodible soils, occasional heavy rainfalls and anthropogenic activities that have transformed large surfaces of natural forest into croplands. In the mountains of the central Rif (Morocco) the anthropogenic pressure by intensive agriculture on steep slopes and grazing practices is causing large impacts on soils. In the region soil losses have further indirect impact on water resources due to siltation of water bodies from canals, small check dams to large reservoirs. Besides the loss of the upper rich organic soil horizons containing the largest amounts of organic matter is causing decreases in soil fertility and losses in crop productivity. Soil erosion affects the spatial variability of soil nutrients of which soil organic carbon (SOC) is one of the most important because is directly linked to soil quality and soil functions. The artificially emitted 137Cs has been found to effectively trace soil redistribution because of its associated movement with fine soil particles including the organic matter. To assess the contents of SOC under different land uses a set of transects were set up in the Sahla catchment that holds a reservoir and is representative of the Rif mountain agroecosystems. Along the transects soil sampling was done to collect soil cores extending until a depth of 25 cm that were sectioned at 5cm depth intervals. The SOC content (%) was measured by the oxidation method in the < 2mm fraction of the interval subsamples. The lateral and vertical variations of SOC contents were examined in combination with the 137Cs profiles to gain information on the nutrient content in the soils under the most characteristic land uses existing in the catchment. In general the SOC contents are low but the mean contents in the croplands are much lower than in the uncultivated lands that present the highest variations in the SOC percentages. In croplands the depth distribution of SOC is homogeneous and the SOC profiles match the vertical distribution of 137Cs revealing the mixing of the soil by tillage. The lateral and vertical distributions of SOC allowed to gain information on the status of soil degradation under the different land uses which is of interest to support management practices aimed to preserve the soils and maintain the sustainability of agroecosystems.

  16. Trait-based characterisation of soil exploitation strategies of banana, weeds and cover plant species

    PubMed Central

    Tardy, Florence; Damour, Gaëlle; Dorel, Marc; Moreau, Delphine

    2017-01-01

    Cover plants can be introduced in cropping systems to provide agroecosystem services, including weed control via competition for resources. There is currently no consensus on how to identify the best cover plant species, while trait-based approaches are promising for screening plant species due to their agroecosystem service provision potential. This study was carried out to characterize soil exploitation strategies of cover plant species in banana agroecosystems using a trait-based approach, and in turn identify cover plant species with a high weed control potential via competition for soil resources in banana cropping systems. A field experiment was conducted on 17 cover plant species, two weed species and two banana cultivars grown individually. Four functional traits were measured. Two of them (i.e., the size of the zone explored by roots and the root impact density) were used to characterize root system soil exploration patterns. Two other traits (i.e., specific root length and root diameter) were used to characterize resource acquisition within the soil zone explored by the roots. All studied traits exhibited marked variations among species. The findings suggested a trade-off between the abilities of species to develop a limited number of large diameter roots exploring a large soil zone versus many thin roots exploring a smaller soil zone. Three soil-resource exploitation strategies were identified among species: (i) with large diameter roots that explore a large soil zone; (ii) with small diameter roots and a high specific length that explore a smaller soil zone; and (iii) with a high total root-impact density and an intermediate specific root length that explore the uppermost soil layers. Interestingly, in our panel of species, no correlations with regard to belowground and aboveground strategies were noted: species with an acquisitive belowground strategy could display an acquisitive or a conservative aboveground strategy. The findings of this study illustrated that a trait-based approach could be used to identify plant species with potential for competing with weeds, while minimising competition with banana. Six of the 17 studied cover crop species were identified as having this potential. The next step will be to assess them for their weed control performances in banana cropping systems with low reliance on herbicides. PMID:28257454

  17. Trait-based characterisation of soil exploitation strategies of banana, weeds and cover plant species.

    PubMed

    Tardy, Florence; Damour, Gaëlle; Dorel, Marc; Moreau, Delphine

    2017-01-01

    Cover plants can be introduced in cropping systems to provide agroecosystem services, including weed control via competition for resources. There is currently no consensus on how to identify the best cover plant species, while trait-based approaches are promising for screening plant species due to their agroecosystem service provision potential. This study was carried out to characterize soil exploitation strategies of cover plant species in banana agroecosystems using a trait-based approach, and in turn identify cover plant species with a high weed control potential via competition for soil resources in banana cropping systems. A field experiment was conducted on 17 cover plant species, two weed species and two banana cultivars grown individually. Four functional traits were measured. Two of them (i.e., the size of the zone explored by roots and the root impact density) were used to characterize root system soil exploration patterns. Two other traits (i.e., specific root length and root diameter) were used to characterize resource acquisition within the soil zone explored by the roots. All studied traits exhibited marked variations among species. The findings suggested a trade-off between the abilities of species to develop a limited number of large diameter roots exploring a large soil zone versus many thin roots exploring a smaller soil zone. Three soil-resource exploitation strategies were identified among species: (i) with large diameter roots that explore a large soil zone; (ii) with small diameter roots and a high specific length that explore a smaller soil zone; and (iii) with a high total root-impact density and an intermediate specific root length that explore the uppermost soil layers. Interestingly, in our panel of species, no correlations with regard to belowground and aboveground strategies were noted: species with an acquisitive belowground strategy could display an acquisitive or a conservative aboveground strategy. The findings of this study illustrated that a trait-based approach could be used to identify plant species with potential for competing with weeds, while minimising competition with banana. Six of the 17 studied cover crop species were identified as having this potential. The next step will be to assess them for their weed control performances in banana cropping systems with low reliance on herbicides.

  18. Biogeochemical Cycles in Degraded Lands

    NASA Technical Reports Server (NTRS)

    Davidson, Eric A.; Vieira, Ima Celia G.; ReisdeCarvalho, Claudio Jose; DeanedeAbreuSa, Tatiana; deSouzaMoutinho, Paulo R.; Figueiredo, Ricardo O.; Stone, Thomas A.

    2004-01-01

    The objectives of this project were to define and describe the types of landscapes that fall under the broad category of "degraded lands" and to study biogeochemical cycles across this range of degradation found in secondary forests. We define degraded land as that which has lost part of its capacity of renovation of a productive ecosystem, either in the context of agroecosystems or as native communities of vegetation. This definition of degradation permits evaluation of biogeochemical constraints to future land uses.

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

    PubMed Central

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

    2013-01-01

    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. PMID:24271002

  20. Mobility and dissipation of chlorpyriphos and quinalphos in sandy clay loam in an agroecosystem-a laboratory-based soil column study.

    PubMed

    G P, Bindumol; C C, Harilal

    2017-09-15

    Leaching potential of pesticides, apart from climatological factors, depends on soil physical properties, soil-pesticide interaction and chemical nature of the molecule. Recent investigations have revealed the presence of various organophosphate pesticides in various agroecosystems. The present study investigated the soil transport mechanism of commonly used organophosphate pesticides in acidic sandy clay loam soils of Kerala State, India. Packed soil column experiment was undertaken under laboratory condition for 30 days. Unsaturated flow was carried out using distilled water/0.01 M CaCl 2 solution after applying chlorpyriphos and quinalphos at the rate of 0.04% a.i.ha -1 and 0.025% a.i.ha -1 , respectively. The study revealed the retention of residues of chlorpyriphos and quinalphos in the top 5-cm layer. Irrespective of the applied concentration of chlorpyriphos and quinalphos, the relative concentration of the pesticides in soil was similar. About 56% of the applied chemicals were dissipated in 30 days of unsaturated flow. A new dissipation compound iron, tricarbonyl [N-(phenyl-2-pyridinylmethyene) benzenamine-N, N'], was detected in GCMS analysis of soil extract from distilled water percolated soil. The dissipation of chlorpyriphos and quinalphos was faster in 0.01 M CaCl 2 -treated soil column. Among the pesticides analysed, the residue of quinalphos was detected in leachate.

  1. Adsorption, desorption and mobility of metsulfuron-methyl in soils of the oil palm agroecosystem in Malaysia.

    PubMed

    Ismail, B S; Ooi, K E

    2012-05-01

    Laboratory experiments were conducted to evaluate adsorption, desorption and mobility of metsulfuron-methyl in soils of the oil palm agroecosystem consisting of the Bernam, Selangor, Rengam and Bongor soil series. The lowest adsorption of metsulfuron-methyl occurred in the Bongor soil (0.366 ml g(-1)), and the highest in the Bemam soil (2.837 ml g(-1). The K(fads) (Freundlich) values of metsulfuron-methyl were 0.366, 0.560, 1.570 and 2.837 ml g(-1) in Bongor, Rengam, Selangor and Bemam soil, respectively. The highest K(fdes) value of metsulfuron-methyl, observed in the Bemam soil, was 2.563 indicating low desorption 0.280 (relatively strong retention). In contrast, the lowest K(fdes) value of 0.564 was observed for the Bongor soil, which had the lowest organic matter (1.43%) and clay content (13.2%). Soil organic matter and clay content were the main factors affecting the adsorption of metsulfuron-methyl. The results of the soil column leaching studies suggested that metsulfuron-methyl has a moderate potential for mobility in the Bernam and Bongor soil series with 19.3% and 39%, respectively for rainfall at 200 mm. However, since metsulfuron-methyl is applied at a very low rate (the maximum field application rate used was 30 g ha(-1)) and is susceptible to biodegradation, the potential forground water contamination is low.

  2. Transgenerational effects of insecticides-implications for rapid pest evolution in agroecosystems.

    PubMed

    Brevik, Kristian; Lindström, Leena; McKay, Stephanie D; Chen, Yolanda H

    2018-04-01

    Although pesticides are a major selective force in driving the evolution of insect pests, the evolutionary processes that give rise to insecticide resistance remain poorly understood. Insecticide resistance has been widely observed to increase with frequent and intense insecticide exposure, but can be lost following the relaxation of insecticide use. One possible but rarely explored explanation is that insecticide resistance may be associated with epigenetic modifications, which influence the patterning of gene expression without changing underlying DNA sequence. Epigenetic modifications such as DNA methylation, histone modifications, and small RNAs have been observed to be heritable in arthropods, but their role in the context of rapid evolution of insecticide resistance remain poorly understood. Here, we discuss evidence supporting how: firstly, insecticide-induced effects can be transgenerationally inherited; secondly, epigenetic modifications are heritable; and thirdly, epigenetic modifications are responsive to pesticide and xenobiotic stress. Therefore, pesticides may drive the evolution of resistance via epigenetic processes. Moreover, insect pests primed by pesticides may be more tolerant of other stress, further enhancing their success in adapting to agroecosystems. Resolving the role of epigenetic modifications in the rapid evolution of insect pests has the potential to lead to new approaches for integrated pest management as well as improve our understanding of how anthropogenic stress may drive the evolution of insect pests. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Food security in a perfect storm: using the ecosystem services framework to increase understanding

    PubMed Central

    Poppy, G. M.; Chiotha, S.; Eigenbrod, F.; Harvey, C. A.; Honzák, M.; Hudson, M. D.; Jarvis, A.; Madise, N. J.; Schreckenberg, K.; Shackleton, C. M.; Villa, F.; Dawson, T. P.

    2014-01-01

    Achieving food security in a ‘perfect storm’ scenario is a grand challenge for society. Climate change and an expanding global population act in concert to make global food security even more complex and demanding. As achieving food security and the millennium development goal (MDG) to eradicate hunger influences the attainment of other MDGs, it is imperative that we offer solutions which are complementary and do not oppose one another. Sustainable intensification of agriculture has been proposed as a way to address hunger while also minimizing further environmental impact. However, the desire to raise productivity and yields has historically led to a degraded environment, reduced biodiversity and a reduction in ecosystem services (ES), with the greatest impacts affecting the poor. This paper proposes that the ES framework coupled with a policy response framework, for example Driver-Pressure-State-Impact-Response (DPSIR), can allow food security to be delivered alongside healthy ecosystems, which provide many other valuable services to humankind. Too often, agro-ecosystems have been considered as separate from other natural ecosystems and insufficient attention has been paid to the way in which services can flow to and from the agro-ecosystem to surrounding ecosystems. Highlighting recent research in a large multi-disciplinary project (ASSETS), we illustrate the ES approach to food security using a case study from the Zomba district of Malawi. PMID:24535394

  4. [Diversity of Hemiptera Auchenorrhyncha in citrus, coffee and a fragment of native forest of the state of São Paulo].

    PubMed

    Giustolin, Teresinha A; Lopes, João R S; Querino, Ranyse B; Cavichioli, Rodney R; Zanol, Kety; Azevedo Filho, Wilson S; Mendes, Miguel A

    2009-01-01

    The population of Hemiptera Auchenorrhyncha was studied in sweet citrus groves (Citrus sinensis), coffee plantations (Coffea arabica) and a semi-deciduous seasonal forest with shrub physiognomy in Bebedouro, SP, to evaluate the influence of the natural ecosystem on the species composition of the agroecosystems. Monitoring was carried out by using yellow stick cards, which were replaced every 15 days and all Auchenorrhyncha collected were counted and identified. Seven families, 11 subfamilies and 98 species were collected, with Cicadellidae being the most abundant. The native forest presented larger wealth, diversity and equitability of Auchenorrhyncha species, demonstrating to be more stable than the other habitats. The high values of similarities obtained between the agroecosystems and the forest demonstrated that great part of Auchenorrhyncha species occurring in the agricultural habitats was also occurring at the forest, indicating that the last may serve as reservoir of species. The abundance of the taxonomic groups of Auchenorrhyncha collected varied with the evaluated habitats, with Proconiini being the most abundant in the coffee plantation next to the forest, Athysanini, Scaphytopiini, Neocoelidiinae and Coelidiinae in the orange orchard and coffee plantation distant from the forest; Cicadellinae and Agalliinae were not related to any of the habitats. The presence of vector insects and possible vectors of plant diseases in the appraised habitats indicate the need of the implementation of strategies for landscape management.

  5. Characterization of competitive interactions in the coexistence of Bt-transgenic and conventional rice.

    PubMed

    Liu, Yongbo; Ge, Feng; Liang, Yuyong; Wu, Gang; Li, Junsheng

    2015-04-26

    Transgene flow through pollen and seeds leads to transgenic volunteers and feral populations in the nature, and consumer choice and economic incentives determine whether transgenic crops will be cultivated in the field. Transgenic and non-transgenic plants are likely to coexist in the field and natural habitats, but their competitive interactions are not well understood. Field experiments were conducted in an agricultural ecosystem with insecticide spraying and a natural ecosystem, using Bt-transgenic rice (Oryza sativa) and its non-transgenic counterpart in pure and mixed stands with a replacement series. Insect damage and competition significantly decreased plant growth and reproduction under the coexistence of transgenic and conventional rice. Insect-resistant transgenic rice was not competitively superior to its counterpart under different densities in both agricultural and natural ecosystems, irrespective of insect infection. Fitness cost due to Bt-transgene expression occurred only in an agroecosystem, where the population yield decreased with increasing percentage of transgenic rice. The population yield fluctuated in a natural ecosystem, with slight differences among pure and mixed stands under plant competition or insect pressure. The presence of Chilo suppressalis infection increased the number of non-target insects. Plant growth and reproduction patterns, relative competition ability and population yield indicate that Bt-transgenic and non-transgenic rice can coexist in agroecosystems, whereas in more natural habitats, transgenic rice is likely to outcompete non-transgenic rice.

  6. Climate change impacts on soil carbon storage in global croplands: 1901-2010

    NASA Astrophysics Data System (ADS)

    Ren, W.; Tian, H.

    2015-12-01

    New global data finds 12% of earth's surface in cropland at present. Croplands will take on the responsibility to support approximate 60% increase in food production by 2050 as FAO estimates. In addition to nutrient supply to plants, cropland soils also play a major source and sink of greenhouse gases regulating global climate system. It is a big challenge to understand how soils function under global changes, but it is also a great opportunity for agricultural sector to manage soils to assure sustainability of agroecosystems and mitigate climate change. Previous studies have attempted to investigate the impacts of different land uses and climates on cropland soil carbon storage. However, large uncertainty still exists in magnitude and spatiotemporal patterns of global cropland soil organic carbon, due to the lack of reliable environmental databases and relatively poorly understanding of multiple controlling factors involved climate change and land use etc. Here, we use a process-based agroecosystem model (DLEM-Ag) in combination with diverse data sources to quantify magnitude and tempo-spatial patterns of soil carbon storage in global croplands during 1901-2010. We also analyze the relative contributions of major environmental variables (climate change, land use and management etc.). Our results indicate that intensive land use management may hidden the vulnerability of cropland soils to climate change in some regions, which may greatly weaken soil carbon sequestration under future climate change.

  7. Trading biodiversity for pest problems.

    PubMed

    Lundgren, Jonathan G; Fausti, Scott W

    2015-07-01

    Recent shifts in agricultural practices have resulted in altered pesticide use patterns, land use intensification, and landscape simplification, all of which threaten biodiversity in and near farms. Pests are major challenges to food security, and responses to pests can represent unintended socioeconomic and environmental costs. Characteristics of the ecological community influence pest populations, but the nature of these interactions remains poorly understood within realistic community complexities and on operating farms. We examine how species diversity and the topology of linkages in species' abundances affect pest abundance on maize farms across the Northern Great Plains. Our results show that increased species diversity, community evenness, and linkage strength and network centrality within a biological network all correlate with significantly reduced pest populations. This supports the assertion that reduced biological complexity on farms is associated with increased pest populations and provides a further justification for diversification of agroecosystems to improve the profitability, safety, and sustainability of food production systems. Bioinventories as comprehensive as the one conducted here are conspicuously absent for most agroecosystems but provide an important baseline for community and ecosystem ecology and the effects of food production on local biodiversity and ecosystem function. Network analyses of abundance correlations of entire communities (rather than focal interactions, for example, trophic interactions) can reveal key network characteristics, especially the importance and nature of network centrality, which aid in understanding how these communities function.

  8. Trading biodiversity for pest problems

    PubMed Central

    Lundgren, Jonathan G.; Fausti, Scott W.

    2015-01-01

    Recent shifts in agricultural practices have resulted in altered pesticide use patterns, land use intensification, and landscape simplification, all of which threaten biodiversity in and near farms. Pests are major challenges to food security, and responses to pests can represent unintended socioeconomic and environmental costs. Characteristics of the ecological community influence pest populations, but the nature of these interactions remains poorly understood within realistic community complexities and on operating farms. We examine how species diversity and the topology of linkages in species’ abundances affect pest abundance on maize farms across the Northern Great Plains. Our results show that increased species diversity, community evenness, and linkage strength and network centrality within a biological network all correlate with significantly reduced pest populations. This supports the assertion that reduced biological complexity on farms is associated with increased pest populations and provides a further justification for diversification of agroecosystems to improve the profitability, safety, and sustainability of food production systems. Bioinventories as comprehensive as the one conducted here are conspicuously absent for most agroecosystems but provide an important baseline for community and ecosystem ecology and the effects of food production on local biodiversity and ecosystem function. Network analyses of abundance correlations of entire communities (rather than focal interactions, for example, trophic interactions) can reveal key network characteristics, especially the importance and nature of network centrality, which aid in understanding how these communities function. PMID:26601223

  9. Improving spatio-temporal benefit transfers for pest control by generalist predators in cotton in the southwestern U.S.

    USGS Publications Warehouse

    Wiederholt, Ruscena; Bagstad, Kenneth J.; McCracken, Gary F.; Diffendorfer, Jay E.; Loomis, John B.; Semmens, Darius J.; Russell, Amy L.; Sansone, Chris; LaSharr, Kelsie; Cryan, Paul; Reynoso, Claudia; Medellin, Rodrigo A.; Lopez-Hoffman, Laura

    2017-01-01

    Given rapid changes in agricultural practice, it is critical to understand how alterations in ecological, technological, and economic conditions over time and space impact ecosystem services in agroecosystems. Here, we present a benefit transfer approach to quantify cotton pest-control services provided by a generalist predator, the Mexican free-tailed bat (Tadarida brasiliensis mexicana), in the southwestern United States. We show that pest-control estimates derived using (1) a compound spatial–temporal model – which incorporates spatial and temporal variability in crop pest-control service values – are likely to exhibit less error than those derived using (2) a simple-spatial model (i.e., a model that extrapolates values derived for one area directly, without adjustment, to other areas) or (3) a simple-temporal model (i.e., a model that extrapolates data from a few points in time over longer time periods). Using our compound spatial–temporal approach, the annualized pest-control value was \\$12.2 million, in contrast to an estimate of \\$70.1 million (5.7 times greater), obtained from the simple-spatial approach. Using estimates from one year (simple-temporal approach) revealed large value differences (0.4 times smaller to 2 times greater). Finally, we present a detailed protocol for valuing pest-control services, which can be used to develop robust pest-control transfer functions for generalist predators in agroecosystems.

  10. The Cook Agronomy Farm LTAR: Knowledge Intensive Precision Agro-ecology

    NASA Astrophysics Data System (ADS)

    Huggins, D. R.

    2015-12-01

    Drowning in data and starving for knowledge, agricultural decision makers require evidence-based information to enlighten sustainable intensification. The agro-ecological footprint of the Cook Agronomy Farm (CAF) Long-Term Agro-ecosystem Research (LTAR) site is embedded within 9.4 million ha of diverse land uses primarily cropland (2.9 million ha) and rangeland (5.3 million ha) that span a wide annual precipitation gradient (150 mm through 1400 mm) with diverse social and natural capital (see Figure). Sustainable intensification hinges on the development and adoption of precision agro-ecological practices that rely on meaningful spatio-temporal data relevant to land use decisions at within-field to regional scales. Specifically, the CAF LTAR will provide the scientific foundation (socio-economical and bio-physical) for enhancing decision support for precision and conservation agriculture and synergistic cropping system intensification and diversification. Long- and short-term perspectives that recognize and assess trade-offs in ecosystem services inherent in any land use decision will be considered so as to promote the development of more sustainable agricultural systems. Presented will be current and future CAF LTAR research efforts required for the development of sustainable agricultural systems including cropping system cycles and flows of nutrients, water, carbon, greenhouse gases and other biotic and abiotic factors. Evaluation criteria and metrics associated with long-term agro-ecosystem provisioning, supporting, and regulating services will be emphasized.

  11. Are carrots, corn and cattle really provided by Nature- If not ...

    EPA Pesticide Factsheets

    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 purpose (or use) to human beneficiaries. This early decision provides the foundation for what ecosystem services are, who uses them, and if or how they can be quantified. An important point to consider is that agricultural activities, while performed in and on environments provided by nature, are characterized by human labor and capital originating in the human economy. There are inherent reasons to quantify (i.e., measure) ecosystem services in a relatively standard way across landscapes and even within political units, such as counties or nations. Standard approaches to defining and measuring can underpin a multitude of accounting activities such as assigning value to them using either monetary or non-monetary approaches. The ecosystem services community could benefit by applying an ecosystem services definition that embodies from where in the environment the “service” originates and, equally as important, the user or beneficiary of this service. If we focus on the subset of ecosystem services which are Final Ecosystem Goods and Services by adopting the definition of Final Ecosystem Goods and Services (or FEGS), “components of nature, directly enjoyed, consumed or used to yi

  12. Role of native shrubs of the Sahel in mitigating water and nutrient stresses of agricultural crops

    NASA Astrophysics Data System (ADS)

    Bayala, R.; Ghezzehei, T. A.; Bogie, N. A.; Diedhiou, I.; Dick, R.

    2015-12-01

    In the semi arid zone of the Sahel native woody shrubs are present in many farmers' fields. The native density of these shrubs is fairly low at around 200 to 300 individuals per hectare. An ongoing study in the Peanut Basin, Senegal has shown a vast improvement in crop yields when annual food crops are planted with the shrub Guiera senegalensis, especially in years of low or irregular precipitation. Shrubs in field plots established in 2003 where a rotation of peanuts and millet are grown are planted at a much higher density of 1500-1830 individuals per hectare. In order to increase the density of shrubs on the landscape, the shrubs must be cultivated. We monitored soil moisture, soil temperature, and growth of recently transplanted individuals at a field station in Thies, Senegal.This study seeks to determine the growth characteristics and water use of young shrubs in order to inform possible future plantations of the shrubs in a more intensely managed agroecosystem. If this technique of intercropping is to be expanded we must not exceed the carrying capacity of the landscape. In vulnerable ecosystems where natural resources are scarce and farming inputs are low, we must work to determine ways of exploiting the adaptation of local agroecosystems to increase the sustainability of agriculture in the region.

  13. Influence of Bacillus spp. isolated from maize agroecosystem on growth and aflatoxin B(1) production by Aspergillus section Flavi.

    PubMed

    Bluma, Romina V; Etcheverry, Miriam G

    2006-03-01

    A total of 59 bacteria of the Bacillus genus were isolated from different components of a maize agroecosystem and their antifungal activity against Aspergillus section Flavi was evaluated. Thirty-three and 46% of these bacteria were able to inhibit Aspergillus flavus Link and A. parasiticus Speare respectively at water activity (a(w)) 0.982; however, when a(w) was 0.955, these percentages were decreased and only three isolates were able to inhibit Aspergillus section Flavi. The majority of bacilli acted as contact antagonists, while a small number of isolates were able to form inhibition zones. In maize meal extract agar, Aspergillus section Flavi growth rate and aflatoxin B(1) (AFB(1)) production were significantly reduced when these strains were paired at a(w) 0.982 with bacilli at all inoculum levels studied. However, two bacilli isolated were able to reduce growth rate and aflatoxin production when a(w) was 0.955. Lag phase increase followed the same general pattern as growth rate reduction. When Aspergillus section Flavi was grown in sterile maize in the presence of three Bacillus strains at a(w) 0.982, the reduction in count (colony-forming units (cfu) g(-1) maize) was less than 30%, except when Aspergillus section Flavi grew with Bacillus amyloliquefaciens UNRCLR. However, levels of detectable AFB(1) were significantly reduced in these interactions at a(w) 0.982.

  14. Behaviour of bentazon as influenced by water and tillage management in rice-growing conditions.

    PubMed

    López-Piñeiro, Antonio; Peña, David; Albarrán, Ángel; Sánchez-Llerena, Javier; Rato-Nunes, José Manuel; Rozas, María Ángeles

    2017-06-01

    Bentazon is a widely used herbicide in rice agroecosystems that has commonly been found in water resources. To assess how tillage and water regimes affect sorption/desorption, dissipation and leaching of bentazon in Mediterranean rice-growing conditions, field experiments were carried out using tillage and flooding (TF), tillage and sprinkler irrigation (TS), no-tillage and sprinkler irrigation (NTS) and long-term no-tillage and sprinkler irrigation (NTS7). After 3 years, the K d values in TS were 2.3, 1.6 and 1.7 times lower than the values in NTS7, NTS and TF respectively. Greater sorption of bentazon was related to higher contents in total organic carbon and, although to a lesser extent, in humic acids and dissolved organic carbon. The persistence of bentazon was significantly greater under anaerobic (half-life DT 50 = 94.1-135 days) than under aerobic (DT 50 = 42.4-91.3 days) incubation conditions for all management regimes. Leaching losses of bentazon were reduced from 78 and 74% in TS and TF to 61 and 62% in NTS7 and NTS respectively. The mid- and long-term implementation of sprinkler irrigation in combination with no-tillage could be considered a management system that is effective at reducing water contamination by bentazon in Mediterranean rice-growing agroecosystems. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  15. Food security in a perfect storm: using the ecosystem services framework to increase understanding.

    PubMed

    Poppy, G M; Chiotha, S; Eigenbrod, F; Harvey, C A; Honzák, M; Hudson, M D; Jarvis, A; Madise, N J; Schreckenberg, K; Shackleton, C M; Villa, F; Dawson, T P

    2014-04-05

    Achieving food security in a 'perfect storm' scenario is a grand challenge for society. Climate change and an expanding global population act in concert to make global food security even more complex and demanding. As achieving food security and the millennium development goal (MDG) to eradicate hunger influences the attainment of other MDGs, it is imperative that we offer solutions which are complementary and do not oppose one another. Sustainable intensification of agriculture has been proposed as a way to address hunger while also minimizing further environmental impact. However, the desire to raise productivity and yields has historically led to a degraded environment, reduced biodiversity and a reduction in ecosystem services (ES), with the greatest impacts affecting the poor. This paper proposes that the ES framework coupled with a policy response framework, for example Driver-Pressure-State-Impact-Response (DPSIR), can allow food security to be delivered alongside healthy ecosystems, which provide many other valuable services to humankind. Too often, agro-ecosystems have been considered as separate from other natural ecosystems and insufficient attention has been paid to the way in which services can flow to and from the agro-ecosystem to surrounding ecosystems. Highlighting recent research in a large multi-disciplinary project (ASSETS), we illustrate the ES approach to food security using a case study from the Zomba district of Malawi.

  16. Soil Microbiome Is More Heterogeneous in Organic Than in Conventional Farming System

    PubMed Central

    Lupatini, Manoeli; Korthals, Gerard W.; de Hollander, Mattias; Janssens, Thierry K. S.; Kuramae, Eiko E.

    2017-01-01

    Organic farming system and sustainable management of soil pathogens aim at reducing the use of agricultural chemicals in order to improve ecosystem health. Despite the essential role of microbial communities in agro-ecosystems, we still have limited understanding of the complex response of microbial diversity and composition to organic and conventional farming systems and to alternative methods for controlling plant pathogens. In this study we assessed the microbial community structure, diversity and richness using 16S rRNA gene next generation sequences and report that conventional and organic farming systems had major influence on soil microbial diversity and community composition while the effects of the soil health treatments (sustainable alternatives for chemical control) in both farming systems were of smaller magnitude. Organically managed system increased taxonomic and phylogenetic richness, diversity and heterogeneity of the soil microbiota when compared with conventional farming system. The composition of microbial communities, but not the diversity nor heterogeneity, were altered by soil health treatments. Soil health treatments exhibited an overrepresentation of specific microbial taxa which are known to be involved in soil suppressiveness to pathogens (plant-parasitic nematodes and soil-borne fungi). Our results provide a comprehensive survey on the response of microbial communities to different agricultural systems and to soil treatments for controlling plant pathogens and give novel insights to improve the sustainability of agro-ecosystems by means of beneficial microorganisms. PMID:28101080

  17. Evidence that the Ceratobasidium-like white-thread blight and black rot fungal pathogens from persimmon and tea crops in the Brazilian Atlantic Forest agroecosystem are two distinct phylospecies.

    PubMed

    Ceresini, Paulo C; Costa-Souza, Elaine; Zala, Marcello; Furtado, Edson L; Souza, Nilton L

    2012-04-01

    The white-thread blight and black rot (WTBR) caused by basidiomycetous fungi of the genus Ceratobasidium is emerging as an important plant disease in Brazil, particularly for crop species in the Ericales such as persimmon (Diospyros kaki) and tea (Camellia sinensis). However, the species identity of the fungal pathogen associated with either of these hosts is still unclear. In this work, we used sequence variation in the internal transcribed spacer regions, including the 5.8S coding region of rDNA (ITS-5.8S rDNA), to determine the phylogenetic placement of the local white-thread-blight-associated populations of Ceratobasidium sp. from persimmon and tea, in relation to Ceratobasidium species already described world-wide. The two sister populations of Ceratobasidium sp. from persimmon and tea in the Brazilian Atlantic Forest agroecosystem most likely represent distinct species within Ceratobasidium and are also distinct from C. noxium, the etiological agent of the first description of white-thread blight disease that was reported on coffee in India. The intraspecific variation for the two Ceratobasidium sp. populations was also analyzed using three mitochondrial genes (ATP6, nad1 and nad2). As reported for other fungi, variation in nuclear and mitochondrial DNA was incongruent. Despite distinct variability in the ITS-rDNA region these two populations shared similar mitochondrial DNA haplotypes.

  18. Glyphosate-resistant weeds of South American cropping systems: an overview.

    PubMed

    Vila-Aiub, Martin M; Vidal, Ribas A; Balbi, Maria C; Gundel, Pedro E; Trucco, Frederico; Ghersa, Claudio M

    2008-04-01

    Herbicide resistance is an evolutionary event resulting from intense herbicide selection over genetically diverse weed populations. In South America, orchard, cereal and legume cropping systems show a strong dependence on glyphosate to control weeds. The goal of this report is to review the current knowledge on cases of evolved glyphosate-resistant weeds in South American agriculture. The first reports of glyphosate resistance include populations of highly diverse taxa (Lolium multiflorum Lam., Conyza bonariensis L., C. canadensis L.). In all instances, resistance evolution followed intense glyphosate use in fruit fields of Chile and Brazil. In fruit orchards from Colombia, Parthenium hysterophorus L. has shown the ability to withstand high glyphosate rates. The recent appearance of glyphosate-resistant Sorghum halepense L. and Euphorbia heterophylla L. in glyphosate-resistant soybean fields of Argentina and Brazil, respectively, is of major concern. The evolution of glyphosate resistance has clearly taken place in those agroecosystems where glyphosate exerts a strong and continuous selection pressure on weeds. The massive adoption of no-till practices together with the utilization of glyphosate-resistant soybean crops are factors encouraging increase in glyphosate use. This phenomenon has been more evident in Argentina and Brazil. The exclusive reliance on glyphosate as the main tool for weed management results in agroecosystems biologically more prone to glyphosate resistance evolution. Copyright (c) 2007 Society of Chemical Industry.

  19. Heavy metals in sediments associated with anourous assemblies in agroecosystems of North Argentine

    NASA Astrophysics Data System (ADS)

    Gonzalez Turu, Nancy; Cáceres Díaz, Raúl Omar; Acosta, Rebeca

    2017-04-01

    Heavy metals come from anthropogenic sources, agricultural and industrial, constitute a danger to aquatic biota and are used as an indicator of environmental deterioration. In agroecosystems that use pesticides, surface accumulation occurs by drift and runoff at lower levels of land that are appropriate spaces for the anurans' reproductive activities. Thus, heavy metals usually accumulate in surface sediments and generate an environment of chronic toxicity. The study was carried out at the Experimental Agricultural Station INTA Salta, Cerrillos, pcia. Of Salta, located at 24 ° 53'45''South and 65 ° 27'51''West at a height of 1240 meters. The annual average temperature is 23.8 ° C, the annual variation of the average temperature, corresponds to the "continental" type, with the maximum in the month of December and the minimum in June. The average annual temperature of the soil at 0.10 m. Of depth is 20.4 ° C. The annual distribution of the precipitations indicates the existence of a rainy season between October and April, that concentrates 90% of the precipitations and another one dries the rest of the year, with 720 mm. Of annual rainfall. The soils are of little development of horizons, corresponding to Inceptisols, Ustocrept udico, Series Cerrillos, of alluvial origin, well drained, developed on medium to fine textures, free to loamy loam, poor in organic matter and nitrogen. Soils of fluvio lacustrine origin, rich in silt and weak aggregation. Amphibians have been able to exploit the resources provided by agroecosystems and remain in a metapopulation system within an altered landscape. However, there is a tendency to decrease the density and diversity of amphibians in highly disturbed areas. Some authors suggest that changes in the patterns of amphibian diversity that inhabit agricultural landscapes allow inferring the depopulation of species less tolerant to environmental transformation associated with intensive and sustained agricultural activities over time. In Argentina, the information linking the presence of heavy metals and their influence on population and community parameters in anurans is limited due to the methodological complexity that makes it difficult to test hypotheses. We evaluated a community parameter, species richness (r) as a first indicator of environmental quality, comparing two environments. Both sites were differentiated by the type of crop to which they were destined (fruit and tobacco), differential agronomic management, while they were similar with respect to the hydrological regime and soils. The samples to analyze the anuran assembly in each of the environments consisted of standardized techniques of audio strip transects (AST) and visual encounter surveys (VES) during two breeding seasons in an agroecosystem in the province of Salta, Argentina. Likewise, samples of soils composed of 20 pikes were taken in a transect, separated 5 m. Between each pique, to a depth of 0 to 5 cm. Chromium (Cr) was evaluated; Nickel (Ni); Copper (Cu); Cadmium (Cd); Manganese (Mn); Magnesium (Mg) and Aluminum (Al) in an accredited external services laboratory, using Atomic Absorption Spectroscopy. The results indicate significant differences in the species richness between the two sites (χ2 = 4.55) and an increase in the heavy metal concentration of the Treatment (tobacco) with respect to the Witness (fruit trees) + 52.38% in (Cr); + 21.43% in (Ni); + 155.56% in (Cu); + 100% (Cd); + 12.9% in (Mg) and + 51.31% in (Al). The Treatment had 63.6% fewer species than the Witness, with a similar landscape conformation. Key words: fruit trees, tobacco, soil, wealth, indicator, pesticides.

  20. Early Islamic inter-settlement agroecosystems in coastal sand, Yavneh dunefield, eastern Mediterranean coast, Israel

    NASA Astrophysics Data System (ADS)

    Roskin, Joel; Taxel, Itamar

    2017-04-01

    This study reveals an attempt to condition agriculture in coastal aeolian sand holding a high water table. Twenty-six small sites, clustering in topographic lows of the Yavneh dunefield, southern Israeli coastal plain, yield surficial Early Islamic finds, and eroded 1-2 m high berms built of grey sand partially covered by parabolic and transverse dunes. Small winter ponds develop by some of the sites. A clay loam 2.5 m beneath the surface retains the water table at a depth of 2.2 m. Between the berms, a 10-50 cm thick grey sand unit dating by OSL to 0.9 ka (11th-12th century AD) underlays a loose aeolian sand cover and overlays sand whose upper parts date to 1.1 ka (9th-10th century AD). The grey unit displays slightly improved fertility (phosphate, potassium, nitrogen and calcium carbonate) in relation to the underlying sand suggesting an anthropogenic enrichment of ash and refuse. Particle size is similar to the sand. Organic carbon and magnetic susceptibility values (0-5 SI) values are quite low (0.4-0.8%) for both units. The artifact assemblage is mixed and comprised of small (<10 cm) pottery sherds, ceramic roof tiles, glass, marble and granite fragments, mosaic tesserae, pottery production waste, iron slag, animal bones, seashells, and coins dated between the 8th and 10th century. The artifacts pre-date the OSL age of the underlying grey sand. The pottery shares many characteristics with the rich ceramic assemblage of nearby inland Yavneh. The establishment of the sites may have been executed by the inhabitants of either Yavneh (or another major inland settlement) or the seashore Muslim military stronghold of Yavneh-Yam (Taxel, 2013). The density of the sites is remarkable compared with the paucity of Byzantine sites in the same region, indicating a distinct spatial pattern that served a specific purpose. The lack of buried artifacts and structures suggests that the sites did not serve for permanent/intensive occupation. The widespread utilization of the rich assortment of Early Islamic artifacts but the relatively younger OSL ages of the underlying grey sand and absence of older Byzantine pottery suggests that the artifacts were rapidly dispersed upon the surface, probably from an abandoned and possibly partly pedogenized town dump dating to the 8th-10th century. The sites are interpreted to be part of an extensive agroecosystem comprised of berm-bordered agricultural plots in lows that allowed easy manual or root access to the high water table. The sites' character and ages closely resembles the well-preserved crisscross berms and inter-berm depressions south of ancient Caesarea that date to 0.86 ka (Roskin et al., 2015). The agricultural activity probably lasted no more than several decades to one century but its utility remains a question. The study documents a challenging attempt to utilize uncultivated sand sheets in a Mediterranean environment for agroecosystem expansion, income, control and "greening" of the terrain. This effort partly reminisces other Early Islamic agricultural water systems (e.g. qanats) in arid regions. It demonstrates that spatial agroecosystems can be developed in times that are not necessarily characterized by socio-political stability.

  1. Soil fertility, crop biodiversity, and farmers' revenues: Evidence from Italy.

    PubMed

    Di Falco, Salvatore; Zoupanidou, Elisavet

    2017-03-01

    This paper analyzes the interplay between soil fertility, crop biodiversity, and farmers' revenues. We use a large, original, farm-level panel dataset. Findings indicate that both crop biodiversity and soil fertility have positive effects on farmers' revenues. It is also shown that crop biodiversity and soil fertility may act as substitutes. These results provide evidence for the important role of diversity in the resilience of agroecosystems. Crop diversification can be a potential strategy to support productivity when soils are less fertile.

  2. 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”

    NASA Astrophysics Data System (ADS)

    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.

  3. The Effect of Conservation Tillage and Cover Crop Residue on Beneficial Arthropods and Weed Seed Predation in Acorn Squash.

    PubMed

    Quinn, N F; Brainard, D C; Szendrei, Z

    2016-12-01

    Conservation tillage combined with cover crops or mulching may enhance natural enemy activity in agroecosystems by reducing soil disturbance and increasing habitat structural complexity. In particular, weed seed predation can increase with vegetation cover and reduced tillage, indicating that mulches may improve the quality of the habitat for weed seed foraging. The purpose of this study was to quantify the effects of tillage and mulching for conservation biological control in cucurbit fields. The effects of mulch and reduced tillage on arthropods and rates of weed seed loss from arenas were examined in field trials on sandy soils in 2014 and 2015. Experimental factors included tillage and cover crop, each with two levels: strip-tillage or full-tillage, and cover crop mulch (rye residue) or no cover crop mulch (unmulched). Arthropod abundance on the crop foliage was not affected by tillage or cover crops. Contrary to expectations, epigeal natural enemies of insects and rates of weed seed removal either did not respond to treatments or were greater in full-tilled plots and plots without mulch. Our study demonstrates the potential importance of weed seed predators in reducing weed seedbanks in vegetable agroecosystems, and suggests that early-season tillage may not be detrimental to epigeal predator assemblages. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Energy Profiles of an Agricultural Frontier: The American Great Plains, 1860-2000.

    PubMed

    Cunfer, Geoff; Watson, Andrew; MacFadyen, Joshua

    2018-04-01

    Agro-ecosystem energy profiles reveal energy flows into, within, and out of U.S. Great Plains farm communities across 140 years. This study evaluates external energy inputs such as human labor, machinery, fuel, and fertilizers. It tracks the energy content of land produce, including crops, grazed pasture, and firewood, and also accounts unharvested energy that remains available for wildlife. It estimates energy redirected through livestock feed into draft power, meat, and milk, and estimates the energy content of final produce available for local consumption or market sale. The article presents energy profiles for three case studies in Kansas in 1880, 1930, 1954, and 1997. Two energy transformations occurred during that time. The first, agricultural colonization , saw farm communities remake the landscape, turning native grassland into a mosaic of cropland and pasture, a process that reduced overall landscape energy productivity. A second energy transition occurred in the mid-twentieth century, characterized by fossil fuel energy imports. That outside energy raised harvested and unharvested energy flows, reused biomass energy, and also final produce. This socio-ecological transition increased landscape energy productivity by 33 to 45 percent above pre-settlement conditions in grain-growing regions. These energy developments were not uniform across the plains. Variations in rainfall and soil quality constrained or favored energy productivity in different places. The case studies reveal the spatial variation of energy profiles in Great Plains agro-ecosystems, while the longitudinal approach tracks temporal change.

  5. Fine-scale ecological and economic assessment of climate change on olive in the Mediterranean Basin reveals winners and losers

    PubMed Central

    Ponti, Luigi; Gutierrez, Andrew Paul; Ruti, Paolo Michele; Dell’Aquila, Alessandro

    2014-01-01

    The Mediterranean Basin is a climate and biodiversity hot spot, and climate change threatens agro-ecosystems such as olive, an ancient drought-tolerant crop of considerable ecological and socioeconomic importance. Climate change will impact the interactions of olive and the obligate olive fruit fly (Bactrocera oleae), and alter the economics of olive culture across the Basin. We estimate the effects of climate change on the dynamics and interaction of olive and the fly using physiologically based demographic models in a geographic information system context as driven by daily climate change scenario weather. A regional climate model that includes fine-scale representation of the effects of topography and the influence of the Mediterranean Sea on regional climate was used to scale the global climate data. The system model for olive/olive fly was used as the production function in our economic analysis, replacing the commonly used production-damage control function. Climate warming will affect olive yield and fly infestation levels across the Basin, resulting in economic winners and losers at the local and regional scales. At the local scale, profitability of small olive farms in many marginal areas of Europe and elsewhere in the Basin will decrease, leading to increased abandonment. These marginal farms are critical to conserving soil, maintaining biodiversity, and reducing fire risk in these areas. Our fine-scale bioeconomic approach provides a realistic prototype for assessing climate change impacts in other Mediterranean agro-ecosystems facing extant and new invasive pests. PMID:24706833

  6. Remote measurement of canopy reflectance shows the effects of elevated carbon dioxide and ozone on the structure and functioning of soybeans in a field setting.

    NASA Astrophysics Data System (ADS)

    Gray, S.; Dermody, O.; Delucia, E.

    2006-12-01

    By altering physiological processes and modifying canopy structure, elevated atmospheric CO2 and O3 directly and indirectly change the productivity of agroecosystems. Remote sensing of canopy reflectance can be used to monitor physiological and structural changes in an ecosystem over a growing season. To examine effects of changing tropospheric chemistry on water content, chlorophyll content, and changes in leaf area index (LAI), Free-Air Concentration Enrichment (FACE) technology was used to expose large plots of soybean (Glycine max) to elevated atmospheric CO2, elevated O3 (1.5 x ambient), and combined elevated CO2 and O3. The following indices were calculated from weekly measurements of reflectance: water index (WI), photochemical reflectance index (PRI), chlorophyll index, near-infrared/ red (NIR/red), and normalized difference vegetation index (NDVI). NIR/red and LAI were strongly correlated throughout the growth season; however NDVI and LAI were highly correlated only up to LAI of 3. Exposure to elevated CO2 accelerated early-season canopy development and delayed late-season senescence. Growth in elevated O3 had the opposite effect. Additionally, elevated CO2 compensated for negative effects of O3 when the canopy was exposed to both gases simultaneously. Reflectance indices revealed several physiological and structural responses of this agroecosystem to tropospheric change, and ultimately that elevated CO2 and O3 significantly affected this system's productivity and period for carbon gain.

  7. Contact with a glyphosate-based herbicide has long-term effects on the activity and foraging of an agrobiont wolf spider.

    PubMed

    Behrend, Julia E; Rypstra, Ann L

    2018-03-01

    Animals that live in conventional agroecosystems must cope with a variety of anthropogenic chemicals. Most of the focus of toxicology is on lethality, deformities, or short-term shifts in behavior. However, for animals that succeed in spite of their exposure, it is important to determine if long-term changes are brought on by their experience. We tested the hypothesis that contact with a commercial formulation of a glyphosate-based herbicide would affect the behavior of subsequent instars in the wolf spider, Pardosa milvina, a species that thrives in the agroecosystems of eastern United States. In one experiment, we housed females carrying egg sacs on a surface treated with the herbicide for 7 h. Then we monitored their activity and foraging of the offspring 4 weeks after emergence. We repeated the same tests on adults that had been housed with herbicide during their penultimate stage. In both studies, exposed spiders displayed higher levels of activity and greater capture success than their unexposed counterparts. Exposure of penultimate instar to herbicide had larger effects on the behavior of adult males than adult females. These results suggest that herbicides have the potential to adjust the behavior of individuals in the predator community. Thus, impact on the food web and their positive or negative potential for biological control may extend beyond their role in controlling weeds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Occurrence of pesticide residues in fish from south American rainfed agroecosystems.

    PubMed

    Ernst, Federico; Alonso, Beatriz; Colazzo, Marcos; Pareja, Lucia; Cesio, Verónica; Pereira, Alfredo; Márquez, Alejandro; Errico, Eugenia; Segura, Angel Manuel; Heinzen, Horacio; Pérez-Parada, Andrés

    2018-08-01

    Environmental sustainability of South American rainfed agroecosystems is of current concern. In this work, we evaluate the occurrence of multiple pesticide residues in muscle tissue of wild fish species from two large rivers in South America (Uruguay and Negro Rivers). Two sampling campaigns (representing summer and winter crops) were performed during 2015 targeting a wide biodiversity of fish species used for human consumption (ranging from migratory to non-migratory and from detritivorous to top-predators). Three different localities associated to rainfed agriculture were assessed, two of them enclosed to a RAMSAR site (National Park "Esteros de Farrapos e Islas del Rio Uruguay"). Pesticide residues occurred in muscle tissue of 143 from 149 sampled fishes (96%). Thirty different pesticides were detected at concentrations from <1 to 194μgkg -1 . Incidence of pesticides in fish were tightly related to: i) features of the contaminant: (Kow, environmental persistence and mobility) and ii) intensity of use of particular pesticides and land dedicated to rainfed agriculture. Trifloxystrobin, metolachlor and pyraclostrobin showed the highest rates of occurrence. Of great concern is that strobirulins have highest toxicity to fish from those detected compounds. From the pattern of pesticides occurring for non-migratory fish species it was possible to trend important spatial differences related to the intensity of rainfed agriculture. Results suggest a regular exposition of aquatic wild biota to sublethal concentrations of multiple semi-polar pesticides. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Understanding soil erosion impacts in temperate agroecosystems: bridging the gap between geomorphology and soil ecology using nematodes as a model organism

    NASA Astrophysics Data System (ADS)

    Baxter, C.; Rowan, J. S.; McKenzie, B. M.; Neilson, R.

    2013-11-01

    Soil is a key asset of natural capital, providing a myriad of goods and ecosystem services that sustain life through regulating, supporting and provisioning roles, delivered by chemical, physical and biological processes. One of the greatest threats to soil is accelerated erosion, which raises a natural process to unsustainable levels, and has downstream consequences (e.g.~economic, environmental and social). Global intensification of agroecosystems is a recognised major cause of soil erosion which, in light of predicted population growth and increased demand for food security, will continue or increase. Transport and redistribution of biota by soil erosion has hitherto been ignored and thus is poorly understood. With the move to sustainable intensification this is a key knowledge gap that needs to be addressed. Here we highlight the erosion-energy and effective-erosion-depth continuum in soils, differentiating between different forms of soil erosion, and argue that nematodes are an appropriate model taxa to investigate impacts of erosion on soil biota across scales. We review the different known mechanisms of soil erosion that impact on soil biota in general, and nematodes in particular, and highlight the few detailed studies, primarily from tropical regions, that have considered soil biota. Based on the limited literature and using nematodes as a model organism we outline future research priorities to initially address the important interrelationships between soil erosion processes and soil biota.

  10. Honey bee-collected pollen in agro-ecosystems reveals diet diversity, diet quality, and pesticide exposure.

    PubMed

    Colwell, Megan J; Williams, Geoffrey R; Evans, Rodger C; Shutler, Dave

    2017-09-01

    European honey bees Apis mellifera are important commercial pollinators that have suffered greater than normal overwintering losses since 2007 in North America and Europe. Contributing factors likely include a combination of parasites, pesticides, and poor nutrition. We examined diet diversity, diet nutritional quality, and pesticides in honey bee-collected pollen from commercial colonies in the Canadian Maritime Provinces in spring and summer 2011. We sampled pollen collected by honey bees at colonies in four site types: apple orchards, blueberry fields, cranberry bogs, and fallow fields. Proportion of honey bee-collected pollen from crop versus noncrop flowers was high in apple, very low in blueberry, and low in cranberry sites. Pollen nutritional value tended to be relatively good from apple and cranberry sites and poor from blueberry and fallow sites. Floral surveys ranked, from highest to lowest in diversity, fallow, cranberry, apple, and blueberry sites. Pesticide diversity in honey bee-collected pollen was high from apple and blueberry sites and low from cranberry and fallow sites. Four different neonicotinoid pesticides were detected, but neither these nor any other pesticides were at or above LD 50 levels. Pollen hazard quotients were highest in apple and blueberry sites and lowest in fallow sites. Pollen hazard quotients were also negatively correlated with the number of flower taxa detected in surveys. Results reveal differences among site types in diet diversity, diet quality, and pesticide exposure that are informative for improving honey bee and land agro-ecosystem management.

  11. Biology and management of Avena fatua and Avena ludoviciana: two noxious weed species of agro-ecosystems.

    PubMed

    Bajwa, Ali Ahsan; Akhter, Muhammad Javaid; Iqbal, Nadeem; Peerzada, Arslan Masood; Hanif, Zarka; Manalil, Sudheesh; Hashim, Saima; Ali, Hafiz Haider; Kebaso, Lynda; Frimpong, David; Namubiru, Halima; Chauhan, Bhagirath Singh

    2017-08-01

    Avena fatua and Avena ludoviciana are closely related grass weed species infesting a large number of crops around the world. These species are widely distributed in diverse agro-ecosystems from temperate to sub-tropical regions due to their unique seed traits, successful germination ecology, high competitive ability, and allelopathic potential. A. fatua is more widespread, adaptable, and problematic than A. ludoviciana. Both these species infest major winter and spring crops, including wheat, oat, barley, canola, maize, alfalfa, and sunflower, causing up to 70% yield losses depending on crop species and weed density. Chemical control has been challenged by large-scale herbicide resistance evolution in these weed species. A. fatua is the most widespread herbicide-resistant weed in the world, infesting about 5 million hectares in 13 countries. The use of alternative herbicides with different modes of action has proved effective. Several cultural practices, including diverse crop rotations, cover crops, improved crop competition (using competitive cultivars, high seed rates, narrow row spacing, altered crop geometry), and allelopathic suppression, have shown promise for controlling A. fatua and A. ludoviciana. The integrated use of these cultural methods can reduce the herbicide dose required, and lower dependency on herbicides to control these grasses. Moreover, integrated management may successfully control herbicide-resistant populations of these weed species. The use of integrated approaches based on the knowledge of biology and ecology of A. fatua and A. ludoviciana may help to manage them sustainably in the future.

  12. Evidence that the Ceratobasidium-like white-thread blight and black rot fungal pathogens from persimmon and tea crops in the Brazilian Atlantic Forest agroecosystem are two distinct phylospecies

    PubMed Central

    Ceresini, Paulo C.; Costa-Souza, Elaine; Zala, Marcello; Furtado, Edson L.; Souza, Nilton L.

    2012-01-01

    The white-thread blight and black rot (WTBR) caused by basidiomycetous fungi of the genus Ceratobasidium is emerging as an important plant disease in Brazil, particularly for crop species in the Ericales such as persimmon (Diospyros kaki) and tea (Camellia sinensis). However, the species identity of the fungal pathogen associated with either of these hosts is still unclear. In this work, we used sequence variation in the internal transcribed spacer regions, including the 5.8S coding region of rDNA (ITS-5.8S rDNA), to determine the phylogenetic placement of the local white-thread-blight-associated populations of Ceratobasidium sp. from persimmon and tea, in relation to Ceratobasidium species already described world-wide. The two sister populations of Ceratobasidium sp. from persimmon and tea in the Brazilian Atlantic Forest agroecosystem most likely represent distinct species within Ceratobasidium and are also distinct from C. noxium, the etiological agent of the first description of white-thread blight disease that was reported on coffee in India. The intraspecific variation for the two Ceratobasidium sp. populations was also analyzed using three mitochondrial genes (ATP6, nad1 and nad2). As reported for other fungi, variation in nuclear and mitochondrial DNA was incongruent. Despite distinct variability in the ITS-rDNA region these two populations shared similar mitochondrial DNA haplotypes. PMID:22888299

  13. Fine-scale ecological and economic assessment of climate change on olive in the Mediterranean Basin reveals winners and losers.

    PubMed

    Ponti, Luigi; Gutierrez, Andrew Paul; Ruti, Paolo Michele; Dell'Aquila, Alessandro

    2014-04-15

    The Mediterranean Basin is a climate and biodiversity hot spot, and climate change threatens agro-ecosystems such as olive, an ancient drought-tolerant crop of considerable ecological and socioeconomic importance. Climate change will impact the interactions of olive and the obligate olive fruit fly (Bactrocera oleae), and alter the economics of olive culture across the Basin. We estimate the effects of climate change on the dynamics and interaction of olive and the fly using physiologically based demographic models in a geographic information system context as driven by daily climate change scenario weather. A regional climate model that includes fine-scale representation of the effects of topography and the influence of the Mediterranean Sea on regional climate was used to scale the global climate data. The system model for olive/olive fly was used as the production function in our economic analysis, replacing the commonly used production-damage control function. Climate warming will affect olive yield and fly infestation levels across the Basin, resulting in economic winners and losers at the local and regional scales. At the local scale, profitability of small olive farms in many marginal areas of Europe and elsewhere in the Basin will decrease, leading to increased abandonment. These marginal farms are critical to conserving soil, maintaining biodiversity, and reducing fire risk in these areas. Our fine-scale bioeconomic approach provides a realistic prototype for assessing climate change impacts in other Mediterranean agro-ecosystems facing extant and new invasive pests.

  14. Repression of fungal plant pathogens and fungal-related contaminants: Selected ecosystem services by soil fauna communities in agroecosystems

    NASA Astrophysics Data System (ADS)

    Meyer-Wolfarth, Friederike; Schrader, Stefan; Oldenburg, Elisabeth; Brunotte, Joachim; Weinert, Joachim

    2017-04-01

    In agroecosystems soil-borne fungal plant diseases are major yield-limiting factors which are difficult to control. Fungal plant pathogens, like Fusarium species, survive as a saprophyte in infected tissue like crop residues and endanger the health of the following crop by increasing the infection risk for specific plant diseases. In infected plant organs, these pathogens are able to produce mycotoxins. Mycotoxins like deoxynivalenol (DON) persist during storage, are heat resistant and of major concern for human and animal health after consumption of contaminated food and feed, respectively. Among fungivorous soil organisms, there are representatives of the soil fauna which are obviously antagonistic to a Fusarium infection and the contamination with mycotoxins. Specific members of the soil macro-, meso-, and microfauna provide a wide range of ecosystem services including the stimulation of decomposition processes which may result in the regulation of plant pathogens and the degradation of environmental contaminants. Investigations under laboratory conditions and in field were conducted to assess the functional linkage between soil faunal communities and plant pathogenic fungi (Fusarium culmorum). The aim was to examine if Fusarium biomass and the content of its mycotoxin DON decrease substantially in the presence of soil fauna (earthworms: Lumbricus terrestris, collembolans: Folsomia candida and nematodes: Aphelenchoides saprophilus) in a commercial cropping system managed with conservation tillage located in Northern Germany. The results of our investigations pointed out that the degradation performance of the introduced soil fauna must be considered as an important contribution to the biodegradation of fungal plant diseases and fungal-related contaminants. Different size classes within functional groups and the traits of keystone species appear to be significant for soil function and the provision of ecosystem services as in particular L. terrestris revealed to be the driver of the degradation process. Thus, earthworms contribute to a sustainable control of fungal pathogens like Fusarium and its mycotoxins in wheat straw by reducing the risk of plant diseases and environmental pollution as ecosystem services. Further studies are planned within the EU-project SoilMan under the BiodivERsA network. In context of the suppression of fungal plant pathogens and the detoxification of their mycotoxins by soil organisms in agroecosystems it is hypothesised that (1) processes related to services or disservices are induced and directed by abundance and activity of functional groups of soil biota; (2) dynamics and interaction in the soil biota community control ecosystem function and services.

  15. Comparison of pollinators and natural enemies: a meta-analysis of landscape and local effects on abundance and richness in crops.

    PubMed

    Shackelford, Gorm; Steward, Peter R; Benton, Tim G; Kunin, William E; Potts, Simon G; Biesmeijer, Jacobus C; Sait, Steven M

    2013-11-01

    To manage agroecosystems for multiple ecosystem services, we need to know whether the management of one service has positive, negative, or no effects on other services. We do not yet have data on the interactions between pollination and pest-control services. However, we do have data on the distributions of pollinators and natural enemies in agroecosystems. Therefore, we compared these two groups of ecosystem service providers, to see if the management of farms and agricultural landscapes might have similar effects on the abundance and richness of both. In a meta-analysis, we compared 46 studies that sampled bees, predatory beetles, parasitic wasps, and spiders in fields, orchards, or vineyards of food crops. These studies used the proximity or proportion of non-crop or natural habitats in the landscapes surrounding these crops (a measure of landscape complexity), or the proximity or diversity of non-crop plants in the margins of these crops (a measure of local complexity), to explain the abundance or richness of these beneficial arthropods. Compositional complexity at both landscape and local scales had positive effects on both pollinators and natural enemies, but different effects on different taxa. Effects on bees and spiders were significantly positive, but effects on parasitoids and predatory beetles (mostly Carabidae and Staphylinidae) were inconclusive. Landscape complexity had significantly stronger effects on bees than it did on predatory beetles and significantly stronger effects in non-woody rather than in woody crops. Effects on richness were significantly stronger than effects on abundance, but possibly only for spiders. This abundance-richness difference might be caused by differences between generalists and specialists, or between arthropods that depend on non-crop habitats (ecotone species and dispersers) and those that do not (cultural species). We call this the 'specialist-generalist' or 'cultural difference' mechanism. If complexity has stronger effects on richness than abundance, it might have stronger effects on the stability than the magnitude of these arthropod-mediated ecosystem services. We conclude that some pollinators and natural enemies seem to have compatible responses to complexity, and it might be possible to manage agroecosystems for the benefit of both. However, too few studies have compared the two, and so we cannot yet conclude that there are no negative interactions between pollinators and natural enemies, and no trade-offs between pollination and pest-control services. Therefore, we suggest a framework for future research to bridge these gaps in our knowledge. © 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.

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

    PubMed

    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 application of lime to increase soil pH, increase cation exchange capacity and decrease Al and S toxicities, (ii) the selection of crops which are tolerant to low pH and high concentrations of soluble Al and S, (iii) physically disrupting the hard surface crusts that form on some soils (if <2 cm thick) to allow water infiltration and root penetration, (iv) application of N and K fertilizers, and (v) incorporation of dry ashfall into the soil (if <5 cm thick) to exploit the newly deposited nutrients. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Natural Enemy Abundance in Southeastern Blueberry Agroecosystems: Distance to Edge and Impact of Management Practices.

    PubMed

    Whitehouse, T Seth; Sial, Ashfaq A; Schmidt, Jason M

    2018-02-08

    Natural enemies are valuable components of agroecosystems as they provide biological control services to help regulate pest populations. Promoting biocontrol services can improve sustainability by decreasing pesticide usage, which is a major challenge for the blueberry industry. Our research is the first to compare natural enemy populations in managed (conventional and organic) and unmanaged blueberry systems, in addition to the effects of non-crop habitat. We conducted our study in 10 blueberry orchards during the growing season across the major blueberry producing counties in Georgia, United States. To estimate the spatial distribution of natural enemies, we conducted suction sampling at three locations in each orchard: within the forested border, along the edge of blueberry orchard adjacent to forested border, and within the interior of the blueberry orchard. Natural enemies maintained higher abundance over the season in unmanaged areas when compared with organic or conventional production systems. In the conventional orchards, natural enemies were more abundant in the surrounding non-crop area compared with the interior of the orchard. Populations were more evenly distributed in less intensive systems (organic and unmanaged). Our results indicate spatial structure in natural enemy populations is related to management practice, and less intensive management can retain higher abundance of natural enemies in blueberry systems. Considerations must be made towards promoting ecologically based management practices to sustain natural enemy populations and potentially increase the delivery of biological control services. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Characterization of enteropathogenic and Shiga toxin-producing Escherichia coli in cattle and deer in a shared agroecosystem.

    PubMed

    Singh, Pallavi; Sha, Qiong; Lacher, David W; Del Valle, Jacquelyn; Mosci, Rebekah E; Moore, Jennifer A; Scribner, Kim T; Manning, Shannon D

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) is an important foodborne pathogen. Cattle are suggested to be an important reservoir for STEC; however, these pathogens have also been isolated from other livestock and wildlife. In this study we sought to investigate transmission of STEC, enterohemorrhagic E. coli (EHEC) and enteropathogenic E. coli (EPEC) between cattle and white-tailed deer in a shared agroecosystem. Cattle feces were collected from 100 animals in a Michigan dairy farm in July 2012, while 163 deer fecal samples were collected during two sampling periods (March and June). The locations of deer fecal pellets were recorded via geographic information system mapping and microsatellite multi-locus genotyping was used to link the fecal samples to individual deer at both time points. Following subculture to sorbitol MacConkey agar and STEC CHROMagar, the pathogens were characterized by serotyping, stx profiling, and PCR-based fingerprinting; multilocus sequence typing (MLST) was performed on a subset. STEC and EHEC were cultured from 12 to 16% of cattle, respectively, and EPEC was found in 36%. Deer were significantly less likely to have a pathogen in March vs. June where the frequency of STEC, EHEC, and EPEC was 1, 6, and 22%, respectively. PCR fingerprinting and MLST clustered the cattle- and deer-derived strains together in a phylogenetic tree. Two STEC strains recovered from both animal species shared MLST and fingerprinting profiles, thereby providing evidence of interspecies transmission and highlighting the importance of wildlife species in pathogen shedding dynamics and persistence in the environment and cattle herds.

  19. Fruit and Soil Quality of Organic and Conventional Strawberry Agroecosystems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Reganold, John P.; Andrews, Preston K.; Reeve, Jennifer

    2010-01-01

    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.more » 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.« less

  20. Changes in nitrogen budget and potential risk to the environment over 20years (1990-2010) in the agroecosystems of the Haihe Basin, China.

    PubMed

    Zheng, Mengmeng; Zheng, Hua; Wu, Yingxia; Xiao, Yi; Du, Yihua; Xu, Weihua; Lu, Fei; Wang, Xiaoke; Ouyang, Zhiyun

    2015-02-01

    The nitrogen balance can serve as an indicator of the risk to the environment of nitrogen loss from agricultural land. To investigate the temporal and spatial changes in agricultural nitrogen application and its potential threat to the environment of the Haihe Basin in China, we used a database of county-level agricultural statistics to calculate agricultural nitrogen input, output, surplus intensity, and use efficiency. Chemical fertilizer nitrogen input increased by 51.7% from 1990 to 2000 and by 37.2% from 2000 to 2010, concomitant with increasing crop yields. Simultaneously, the nitrogen surplus intensity increased by 53.5% from 1990 to 2000 and by 16.5% from 2000 to 2010, presenting a continuously increased environmental risk. Nitrogen use efficiency decreased from 0.46 in 1990 to 0.42 in 2000 and remained constant at 0.42 in 2010, partly due to fertilizer composition and type improvement. This level indicates that more than half of nitrogen inputs are lost in agroecosystems. Our results suggest that although the improvement in fertilizer composition and types has partially offset the decrease in nitrogen use efficiency, the environmental risk has still increased gradually over the past 20 years, along with the increase in crop yields and nitrogen application. It is important to achieve a better nitrogen balance through more effective management to significantly reduce the environmental risk, decrease nitrogen surplus intensity, and increase nitrogen use efficiency without sacrificing crop yields. Copyright © 2014. Published by Elsevier B.V.

  1. Effect on the growth and development and induction of abnormalities by a glyphosate commercial formulation and its active ingredient during two developmental stages of the South-American Creole frog, Leptodactylus latrans.

    PubMed

    Bach, Nadia Carla; Natale, Guillermo Sebastián; Somoza, Gustavo Manuel; Ronco, Alicia Estela

    2016-12-01

    We evaluated the acute lethal and sublethal effects of technical-grade glyphosate (GLY) and the GLY-based commercial formulation Roundup ULTRA MAX® (RU) on two Gosner stages (Gss) 25 and 36 of the South-American Creole frog, Leptodactylus latrans. Bioassays were performed following standardized methods within a wide range of concentrations (0.0007-9.62 mg of acid equivalents per liter-a.e./L-of RU and 3-300 mg/L of GLY). The endpoints evaluated were mortality, swimming activity, growth, development, and the presence of morphologic abnormalities, especially in the mouthparts. No lethal effects were observed on larvae exposed to GLY during either Gs-25 or Gs-36. The concentrations inducing 50 % lethality in RU-exposed larvae at different exposure times and Gss ranged from 3.26 to 9.61 mg a.e./L. Swimming activity was affected by only RU. Effects on growth and development and the induction of morphologic abnormalities-like oral abnormalities and edema-were observed after exposure to either GLY or RU. Gs-25 was the most sensitive stage to both forms of the herbicide. The commercial formulation was much more toxic than the active ingredient on all the endpoints assessed. Effects on growth, development, and the induction of morphologic abnormalities observed in the range of environmental concentrations reported for agroecosystems of Argentina constitute an alert to the potential detrimental effects of the herbicide that could be affecting the fitness and survival of anurans in agroecosystems.

  2. The effect of landscape complexity and microclimate on the thermal tolerance of a pest insect.

    PubMed

    Alford, Lucy; Tougeron, Kévin; Pierre, Jean-Sébastien; Burel, Françoise; van Baaren, Joan

    2017-03-21

    Landscape changes are known to exacerbate the impacts of climate change. As such, understanding the combined effect of climate and landscape on agroecosystems is vital if we are to maintain the function of agroecosystems. This study aimed to elucidate the effects of agricultural landscape complexity on the microclimate and thermal tolerance of an aphid pest to better understand how landscape and climate may interact to affect the thermal tolerance of pest species within the context of global climate change. Meteorological data were measured at the landscape level, and cereal aphids (Sitobion avenae, Metopolophium dirhodum and Rhopalosiphum padi) sampled, from contrasting landscapes (simple and complex) in winter 2013/2014 and spring 2014 in cereal fields of Brittany, France. Aphids were returned to the laboratory and the effect of landscape of origin on aphid cold tolerance (as determined by CT min ) was investigated. Results revealed that local landscape complexity significantly affected microclimate, with simple homogenous landscapes being on average warmer, but with greater temperature variation. Landscape complexity was shown to impact aphid cold tolerance, with aphids from complex landscapes being more cold tolerant than those from simple landscapes in both winter and spring, but with differences among species. This study highlights that future changes to land use could have implications for the thermal tolerance and adaptability of insects. Furthermore, not all insect species respond in a similar way to microhabitat and microclimate, which could disrupt important predator-prey relationships and the ecosystem service they provide. © 2017 Institute of Zoology, Chinese Academy of Sciences.

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

    PubMed Central

    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. PMID:25392751

  4. Characterization of enteropathogenic and Shiga toxin-producing Escherichia coli in cattle and deer in a shared agroecosystem

    PubMed Central

    Singh, Pallavi; Sha, Qiong; Lacher, David W.; Del Valle, Jacquelyn; Mosci, Rebekah E.; Moore, Jennifer A.; Scribner, Kim T.; Manning, Shannon D.

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) is an important foodborne pathogen. Cattle are suggested to be an important reservoir for STEC; however, these pathogens have also been isolated from other livestock and wildlife. In this study we sought to investigate transmission of STEC, enterohemorrhagic E. coli (EHEC) and enteropathogenic E. coli (EPEC) between cattle and white-tailed deer in a shared agroecosystem. Cattle feces were collected from 100 animals in a Michigan dairy farm in July 2012, while 163 deer fecal samples were collected during two sampling periods (March and June). The locations of deer fecal pellets were recorded via geographic information system mapping and microsatellite multi-locus genotyping was used to link the fecal samples to individual deer at both time points. Following subculture to sorbitol MacConkey agar and STEC CHROMagar, the pathogens were characterized by serotyping, stx profiling, and PCR-based fingerprinting; multilocus sequence typing (MLST) was performed on a subset. STEC and EHEC were cultured from 12 to 16% of cattle, respectively, and EPEC was found in 36%. Deer were significantly less likely to have a pathogen in March vs. June where the frequency of STEC, EHEC, and EPEC was 1, 6, and 22%, respectively. PCR fingerprinting and MLST clustered the cattle- and deer-derived strains together in a phylogenetic tree. Two STEC strains recovered from both animal species shared MLST and fingerprinting profiles, thereby providing evidence of interspecies transmission and highlighting the importance of wildlife species in pathogen shedding dynamics and persistence in the environment and cattle herds. PMID:25883908

  5. Weakening density dependence from climate change and agricultural intensification triggers pest outbreaks: a 37-year observation of cotton bollworms

    PubMed Central

    Ouyang, Fang; Hui, Cang; Ge, Saiying; Men, Xin-Yuan; Zhao, Zi-Hua; Shi, Pei-Jian; Zhang, Yong-Sheng; Li, Bai-Lian

    2014-01-01

    Understanding drivers of population fluctuation, especially for agricultural pests, is central to the provision of agro-ecosystem services. Here, we examine the role of endogenous density dependence and exogenous factors of climate and human activity in regulating the 37-year population dynamics of an important agricultural insect pest, the cotton bollworm (Helicoverpa armigera), in North China from 1975 to 2011. Quantitative time-series analysis provided strong evidence explaining long-term population dynamics of the cotton bollworm and its driving factors. Rising temperature and declining rainfall exacerbated the effect of agricultural intensification on continuously weakening the negative density dependence in regulating the population dynamics of cotton bollworms. Consequently, ongoing climate change and agricultural intensification unleashed the tightly regulated pest population and triggered the regional outbreak of H. armigera in 1992. Although the negative density dependence can effectively regulate the population change rate to fluctuate around zero at stable equilibrium levels before and after outbreak in the 1992, the population equilibrium jumped to a higher density level with apparently larger amplitudes after the outbreak. The results highlight the possibility for exogenous factors to induce pest outbreaks and alter the population regulating mechanism of negative density dependence and, thus, the stable equilibrium of the pest population, often to a higher level, posing considerable risks to the provision of agro-ecosystem services and regional food security. Efficient and timely measures of pest management in the era of Anthropocene should target the strengthening and revival of weakening density dependence caused by climate change and human activities. PMID:25535553

  6. Weakening density dependence from climate change and agricultural intensification triggers pest outbreaks: a 37-year observation of cotton bollworms.

    PubMed

    Ouyang, Fang; Hui, Cang; Ge, Saiying; Men, Xin-Yuan; Zhao, Zi-Hua; Shi, Pei-Jian; Zhang, Yong-Sheng; Li, Bai-Lian

    2014-09-01

    Understanding drivers of population fluctuation, especially for agricultural pests, is central to the provision of agro-ecosystem services. Here, we examine the role of endogenous density dependence and exogenous factors of climate and human activity in regulating the 37-year population dynamics of an important agricultural insect pest, the cotton bollworm (Helicoverpa armigera), in North China from 1975 to 2011. Quantitative time-series analysis provided strong evidence explaining long-term population dynamics of the cotton bollworm and its driving factors. Rising temperature and declining rainfall exacerbated the effect of agricultural intensification on continuously weakening the negative density dependence in regulating the population dynamics of cotton bollworms. Consequently, ongoing climate change and agricultural intensification unleashed the tightly regulated pest population and triggered the regional outbreak of H. armigera in 1992. Although the negative density dependence can effectively regulate the population change rate to fluctuate around zero at stable equilibrium levels before and after outbreak in the 1992, the population equilibrium jumped to a higher density level with apparently larger amplitudes after the outbreak. The results highlight the possibility for exogenous factors to induce pest outbreaks and alter the population regulating mechanism of negative density dependence and, thus, the stable equilibrium of the pest population, often to a higher level, posing considerable risks to the provision of agro-ecosystem services and regional food security. Efficient and timely measures of pest management in the era of Anthropocene should target the strengthening and revival of weakening density dependence caused by climate change and human activities.

  7. Assessment of surface water quality of inland valleys for cropping in SW Nigeria

    NASA Astrophysics Data System (ADS)

    Aboyeji, O. S.; Ogunkoya, O. O.

    2017-05-01

    Inland valley agro-ecosystems which are a category of wetlands have potential for sustainable crop production relative to uplands. A major challenge to their utilisation in the study area is their heterogeneity in hydrology, morphology, soil types and agro-economy. The study assessed the surface water quality of three typologies of the agro-ecosystems—amphitheatre-like valley-heads (Am), valley-side (VS), and low depression (LD)—for cropping. Surface water of six sites were sampled during the wet and dry seasons. The physicochemical properties and metal concentrations of the samples were analysed. Descriptive statistics and water quality indices were used to assess the suitability of the waters of the agro-ecosystems for cropping. Results showed that the valleys have neutral to slightly alkaline waters. Values of physicochemical parameters are generally within the acceptable range for cropping. The concentration of major cations varied across the inland valley types, but exhibited similar characteristics within each valley. The dominance of the major cations is in the order of Na > Ca > K > Mg. ANOVA results indicated that there is no significant difference in the concentration of heavy metals across the valleys ( F = 2.044, p = 0.138, α = 0.05). Generally, most of the physicochemical parameters and trace metals have low concentrations and are non-toxic to plants. Values of water quality indices (sodium adsorption ratio, soluble sodium percentage, total dissolved solids and permeability index) indicated that the concentrations of minerals in waters across the valley typologies are generally within permissible limits for cropping.

  8. Agro-biodiversity has increased over a 95 year period at sub-regional and regional scales in southern Quebec, Canada

    NASA Astrophysics Data System (ADS)

    Renard, D.; Bennett, E. M.; Rhemtulla, J. M.

    2016-12-01

    Decline in agricultural biodiversity (cultivated species and wild species used for food or that support agro-ecosystem functioning) at the farm scale has fueled concerns about potential negative effects of this biodiversity loss on the ecological and economic sustainability of agro-ecosystems. Despite these concerns, formal assessment of how agro-biodiversity has historically changed at scales larger than individual farms is fragmented. We quantified the changes in the abundance of 10 crop and livestock species, their overall diversity, and the way they were mixed in ‘baskets’ of agricultural products from 1911 to 2006, at a sub-regional (15 Regional County Municipalities) and regional scales. We found that the diversity of agricultural products increased at the regional scale. From 1911 to 1966, the region produced fodder, milk and maple, mixed in two low-diversity baskets. After 1966, the region provided a greater variety of baskets composed of newly introduced cash crops and high-value livestock. All baskets provided were themselves more diverse than historically and varied greatly in composition across space. Increasing regional diversity was related to changes in agricultural policy, while the variation in the composition of baskets produced was related to biophysical and socioeconomic characteristics. Our results indicate that agricultural transformations of the 21th century did not invariably lead to agro-biodiversity loss at large scales. We have also demonstrated that combining diversity measures at multiple scales with the analysis of compositional change of agricultural products over long time periods could improve research on the links between agro-biodiversity dynamics and resilience.

  9. Landscape hydrology and scaling of nitrate 15N and 18O isotope composition in a semi-arid agroecosystem

    NASA Astrophysics Data System (ADS)

    Kelley, C. J.; Martin, R. A.; Keller, C. K.; Orr, C. H.; Huggins, D. R.; Evans, R. D.

    2014-12-01

    Understanding how pore- to hillslope-scale processes combine to control nutrient export at larger scales is a fundamental challenge in today's agroecosystems as the carbon and contamination footprints of production agriculture come under increasing scrutiny. At the Cook Agronomy Farm (CAF) Long-Term Agricultural Research (LTAR) station near Pullman, WA we are using in-field observations to track how local-scale hydrological routing and biogeochemical processing interact to control landscape-scale water and nutrient exports. Previous research at the CAF has shown that conservative tracers and reactive nutrient quantities (NO3-,and DOC concentrations, DOM quality) in landscape-scale drainage can be explained by straightforward mixing of waters from variably contributing areas. Nitrate stable isotope composition in subsurface drain effluent indicate that most leached nitrate originates from reduced nitrogen fertilizer applied to the CAF in the autumn, which undergoes nitrification and subsequent leaching. This occurs over a timespan of weeks to months. However, water samples from contributing areas exhibit nitrate d15N and d18O significantly greater than subsurface drain effluent at all locations, and time-series consistent with the occurrence of denitrification at some locations. Possible explanations include pore-scale processing of nitrogen that does not affect the other tracers (like EC, DOM quality, and DOC concentration), and landscape-scale transport pathways that bypass our field instruments. Through this work we are contributing to a broader understand of how global change and local factors and management practices interact to affect the fate of fertilizer N, which is a cross-cutting research theme of the national LTAR network.

  10. Biosolids affect soil barium in a dryland wheat agroecosystem.

    PubMed

    Ippolito, J A; Barbarick, K A

    2006-01-01

    In December 2003, the USEPA released an amended list of 15 "candidate pollutants for exposure and hazard screening" with regard to biosolids land application, including Ba. Therefore, we decided to monitor soil Ba concentrations from a dryland wheat (Triticum aestivum L.)-fallow agroecosystem experiment. This experiment received 10 biennial biosolids applications (1982-2003) at rates from 0 to 26.8 dry Mg ha(-1) per application year. The study was conducted on a Platner loam (Aridic Paleustoll), approximately 30 km east of Brighton, CO. Total soil Ba, as measured by 4 M HNO(3), increased with increasing biosolids application rate. In the soil-extraction data from 1988 to 2003, however, we observed significant (P < 0.10) linear or exponential declines in ammonium bicarbonate-diethylenetriaminepentaacetic acid (AB-DTPA) extractable Ba concentrations as a function of increasing biosolids application rates. This was observed in 6 of 7 and 3 of 7 yr for the 0- to 20- and 20- to 60-cm soil depths, respectively. Results suggest that while total soil Ba increased as a result of biosolids application with time, the mineral form of Ba was present in forms not extractable with AB-DTPA. Scanning electron microscopy using energy dispersive spectroscopy verified soil Ba-S compounds in the soil surface, probably BaSO(4). Wet chemistry sequential extraction suggested BaCO(3) precipitation was increasing in the soil subsurface. Our research showed that biosolids application may increase total soil Ba, but soil Ba precipitates are insoluble and should not be an environmental concern in similar soils under similar climatic and management conditions.

  11. Contamination from organochlorine pesticides (OCPs) in agricultural soils of Kuttanad agroecosystem in India and related potential health risk.

    PubMed

    Sruthi, S N; Shyleshchandran, M S; Mathew, Sunil Paul; Ramasamy, E V

    2017-01-01

    The presence and distribution of a few organochlorine pesticides (OCPs) in the paddy fields of the Kuttanad agroecosystem (KAE) was examined in the present study. Kuttanad forms a part of the Vembanad wetland system which is a Ramsar site of international importance in the state of Kerala. This study, to the best of our knowledge, is the first report on the occurrence of OCP residues in KAE. Pesticide residue analysis was done with gas chromatograph (GC-ECD). Twenty-one soil samples were collected for the multiresidual analysis of OCPs. Sixteen OCP residues with a notable concentration were observed from the study area. α-BHC; β-BHC; γ-BHC; δ-BHC; α-chlordane; γ-chlordane; heptachlor; 4,4-DDT; 4,4-DDE; 4,4-DDD; α-endosulfan; β-endosulfan; aldrin; dieldrin; endrin aldehyde; and endrin ketone were the residues observed. The percentage-wise occurrence of OCP residues in the soil samples analysed (total of 63 samples from 21 sites, three samples per site) exhibits the following order: Σ BHC˃ Σ chlordane ˃ Σ dieldrin ˃ Σ aldrin ˃ Σ endrin˃ Σ heptachlor = endosulfan˃ Σ DDT. All pesticides detected from KAE are in the list of priority pollutants of US Environmental Protection Agency (USEPA). The distribution pattern of OCPs in the KAE soils revealed their origin as both historical and recent application of pesticides. Health risk assessment of OCP residues on human population was also conducted. The findings indicated that the concentrations of OCPs were within the permissible limits of USEPA, thus, the human population in the study area was safe.

  12. Environmental and habitat drivers of relative abundance for a suite of azteca-attacking Pseudacteon phorid flies.

    PubMed

    Reese, Katlynd M; Philpott, Stacy M

    2012-10-01

    Phoridae (Diptera) have widespread impacts on insect communities by limiting host ant behavior. However, phorid-ant interactions may vary with habitat or environmental conditions. Three Pseudacteon species parasitize Azteca instabilis Fr. Smith, a common ant in coffee agroecosystems, and limit A. instabilis foraging, indirectly benefiting other insects. However, little is known about how phorid abundance, behavior, and effects change with environmental conditions. In shaded coffee systems, coffee (Coffea arabica L.) grows under a range of shade conditions and management changes affect species interactions. For example, Pseudacteon spp. more strongly limit A. instabilis foraging in low-shade coffee habitats. We sampled relative abundance of three phorid species around A. instabilis nests in three coffee habitats varying in shade management during dry and wet seasons. We measured canopy cover, tree richness, tree density, leaf litter depth, and number of nearby trees with A. instabilis to determine whether these habitat factors correlate with phorid abundance. P. laciniosus Brown was the most abundant phorid in both seasons. Phorid relative abundance did not differ by habitat, but did differ by season. P. laciniosus accounted for a higher proportion of phorids in the wet season (91.4%) than in the dry season (78.9%), and P. planidorsalis Brown accounted for a larger percent in the dry season (21.1%) than in the wet season (7.3%). Phorid composition did not differ with habitat type, and none of the measured environmental variables correlated with changes in phorid composition. Thus, phorids in coffee agroecosystems respond to large seasonal differences, but not differences between coffee habitats.

  13. Long-term nitrogen fertilization decreases bacterial diversity and favors the growth of Actinobacteria and Proteobacteria in agro-ecosystems across the globe.

    PubMed

    Dai, Zhongmin; Su, Weiqin; Chen, Huaihai; Barberán, Albert; Zhao, Haochun; Yu, Mengjie; Yu, Lu; Brookes, Philip C; Schadt, Christopher W; Chang, Scott X; Xu, Jianming

    2018-04-12

    Long-term elevated nitrogen (N) input from anthropogenic sources may cause soil acidification and decrease crop yield, yet the response of the belowground microbial community to long-term N input alone or in combination with phosphorus (P) and potassium (K) is poorly understood. We explored the effect of long-term N and NPK fertilization on soil bacterial diversity and community composition using meta-analysis of a global dataset. Nitrogen fertilization decreased soil pH, and increased soil organic carbon (C) and available N contents. Bacterial taxonomic diversity was decreased by N fertilization alone, but was increased by NPK fertilization. The effect of N fertilization on bacterial diversity varied with soil texture and water management, but was independent of crop type or N application rate. Changes in bacterial diversity were positively related to both soil pH and organic C content under N fertilization alone, but only to soil organic C under NPK fertilization. Microbial biomass C decreased with decreasing bacterial diversity under long-term N fertilization. Nitrogen fertilization increased the relative abundance of Proteobacteria and Actinobacteria, but reduced the abundance of Acidobacteria, consistent with the general life history strategy theory for bacteria. The positive correlation between N application rate and the relative abundance of Actinobacteria indicates that increased N availability favored the growth of Actinobacteria. This first global analysis of long-term N and NPK fertilization that differentially affects bacterial diversity and community composition provides a reference for nutrient management strategies for maintaining belowground microbial diversity in agro-ecosystems worldwide. © 2018 John Wiley & Sons Ltd.

  14. Impact of insect growth regulators on the predator Ceraeochrysa cincta (Schneider) (Neuroptera: Chrysopidae).

    PubMed

    Rugno, Gabriel Rodrigo; Zanardi, Odimar Zanuzo; Bajonero Cuervo, Johanna; de Morais, Matheus Rovere; Yamamoto, Pedro Takao

    2016-07-01

    The generalist predator Ceraeochrysa cincta (Schneider) (Neuroptera: Chrysopidae) is an important biological control agent of several arthropod pests in different agroecosystems. This study assessed the lethal and sublethal effects of six insect growth regulators sprayed on first-instar larvae of C. cincta. Lufenuron and diflubenzuron were highly harmful to first-instar larvae of C. cincta, causing 100 % of mortality before they reached the second instar. Buprofezin caused ~25 % mortality of the larvae and considerably reduced the fecundity and longevity of the insects, but substantially increased the proportion of females in the surviving population of C. cincta. Methoxyfenozide and tebufenozide did not affect the duration and survival of the immature stages, but methoxyfenozide significantly reduced the fecundity and longevity of the insects. Pyriproxyfen reduced the survival of the larval stage by 19.5 %, but did not affect the development, survival and reproduction of the surviving individuals. Based on reduction coefficient, the insecticides diflubenzuron and lufenuron were considered harmful to C. cincta, whereas buprofezin and methoxyfenozide were slightly harmful and tebufenozide and pyriproxyfen were harmless. The estimation of life-table parameters indicated that buprofezin and methoxyfenozide significantly reduced the R o , r and λ of C. cincta, whereas pyriproxyfen and tebufenozide caused no adverse effect on population parameters, indicating that these insecticides could be suitable for use in pest management programs towards the conservation and population increase of the predator in agroecosystems. However, more studies should be conducted to evaluate the compatibility of these insecticides with the predator C. cincta under semi-field and field conditions.

  15. Spatial diversification of agroecosystems to enhance biological control and other regulating services: An agroecological perspective.

    PubMed

    Hatt, Séverin; Boeraeve, Fanny; Artru, Sidonie; Dufrêne, Marc; Francis, Frédéric

    2018-04-15

    Spatial diversification of crop and non-crop habitats in farming systems is promising for enhancing natural regulation of insect pests. Nevertheless, results from recent syntheses show variable effects. One explanation is that the abundance and diversity of pests and natural enemies are affected by the composition, design and management of crop and non-crop habitats. Moreover, interactions between both local and landscape elements and practices carried out at different spatial scales may affect the regulation of insect pests. Hence, research is being conducted to understand these interdependencies. However, insects are not the only pests and pests are not the only elements to regulate in agroecosystems. Broadening the scope could allow addressing multiple issues simultaneously, but also solving them together by enhancing synergies. Indeed, spatial diversification of crop and non-crop habitats can allow addressing the issues of weeds and pathogens, along with being beneficial to several other regulating services like pollination, soil conservation and nutrient cycling. Although calls rise to develop multifunctional landscapes that optimize the delivery of multiple ecosystem services, it still represents a scientific challenge today. Enhancing interdisciplinarity in research institutions and building interrelations between scientists and stakeholders may help reach this goal. Despite obstacles, positive results from research based on such innovative approaches are encouraging for engaging science in this path. Hence, the aim of the present paper is to offer an update on these issues by exploring the most recent findings and discussing these results to highlight needs for future research. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Factors Influencing Male Plutella xylostella (Lepidoptera: Plutellidae) Capture Rates in Sex Pheromone-Baited Traps on Canola in Western Canada.

    PubMed

    Miluch, C E; Dosdall, L M; Evenden, M L

    2014-12-01

    Optimization of male moth trapping rates in sex pheromone-baited traps plays a key role in managing Plutella xylostella (L.). We investigated various ways to increase the attractiveness of pheromone-baited traps to P. xylostella in canola agroecosystems in AB, Canada. Factors tested included pheromone blend and dose, addition of a green leaf volatile to the pheromone at different times during the season, lure type, trap color, and height. The industry standard dose of 100 μg of pheromone (four-component blend) per lure (ConTech Enterprises Inc., Delta, British Columbia [BC], Canada) captured the most moths in the two lure types tested. Traps baited with pheromone released from gray rubber septa captured more males than those baited with red rubber septa. Traps baited with lures in which Z11-16: Ac is the main component attracted significantly more moths than those in which Z11-16: Ald is the main component. The addition of the green leaf volatile, (Z)-3-hexenyl acetate, to pheromone at a range of doses, did not increase moth capture at any point during the canola growing season. Unpainted white traps captured significantly more male moths than pheromone-baited traps that were painted yellow. Trap height had no significant effect on moth capture. Recommendations for monitoring P. xylostella in canola agroecosystems of western Canada include using a pheromone blend with Z11-16: Ac as the main component released from gray rubber septa at a dose of 100 μg. © 2014 Entomological Society of America.

  17. Glyphosate and AMPA, "pseudo-persistent" pollutants under real-world agricultural management practices in the Mesopotamic Pampas agroecosystem, Argentina.

    PubMed

    Primost, Jezabel E; Marino, Damián J G; Aparicio, Virginia C; Costa, José Luis; Carriquiriborde, Pedro

    2017-10-01

    In the Pampas, public concern has strongly risen because of the intensive use of glyphosate for weed control and fallow associated with biotech crops. The present study was aimed to evaluate the occurrence and concentration of the herbicide and its main metabolite (AMPA) in soil and other environmental compartments of the mentioned agroecosystem, including groundwater, in relation to real-world agricultural management practices in the region. Occurrence was almost ubiquitous in solid matrices (83-100%) with maximum concentrations among the higher reported in the world (soil: 8105 and 38939; sediment: 3294 and 7219; suspended particulate matter (SPM): 584 and 475 μg/kg of glyphosate and AMPA). Lower detection frequency was observed in surface water (27-55%) with maximum concentrations in whole water of 1.80 and 1.90 μg/L of glyphosate and AMPA, indicating that SPM analysis would be more sensitive for detection in the aquatic ecosystem. No detectable concentrations of glyphosate or AMPA were observed in groundwater. Glyphosate soil concentrations were better correlated with the total cumulative dose and total number of applications than the last spraying event dose, and an increment of 1 mg glyphosate/kg soil every 5 spraying events was estimated. Findings allow to infer that, under current practices, application rates are higher than dissipation rates. Hence, glyphosate and AMPA should be considered "pseudo-persistent" pollutants and a revisions of management procedures, monitoring programs, and ecological risk for soil and sediments should be also recommended. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The influence of genetic drift and selection on quantitative traits in a plant pathogenic fungus.

    PubMed

    Stefansson, Tryggvi S; McDonald, Bruce A; Willi, Yvonne

    2014-01-01

    Genetic drift and selection are ubiquitous evolutionary forces acting to shape genetic variation in populations. While their relative importance has been well studied in plants and animals, less is known about their relative importance in fungal pathogens. Because agro-ecosystems are more homogeneous environments than natural ecosystems, stabilizing selection may play a stronger role than genetic drift or diversifying selection in shaping genetic variation among populations of fungal pathogens in agro-ecosystems. We tested this hypothesis by conducting a QST/FST analysis using agricultural populations of the barley pathogen Rhynchosporium commune. Population divergence for eight quantitative traits (QST) was compared with divergence at eight neutral microsatellite loci (FST) for 126 pathogen strains originating from nine globally distributed field populations to infer the effects of genetic drift and types of selection acting on each trait. Our analyses indicated that five of the eight traits had QST values significantly lower than FST, consistent with stabilizing selection, whereas one trait, growth under heat stress (22°C), showed evidence of diversifying selection and local adaptation (QST>FST). Estimates of heritability were high for all traits (means ranging between 0.55-0.84), and average heritability across traits was negatively correlated with microsatellite gene diversity. Some trait pairs were genetically correlated and there was significant evidence for a trade-off between spore size and spore number, and between melanization and growth under benign temperature. Our findings indicate that many ecologically and agriculturally important traits are under stabilizing selection in R. commune and that high within-population genetic variation is maintained for these traits.

  19. Pollen Foraging Differences Among Three Managed Pollinators in the Highbush Blueberry (Vaccinium corymbosum) Agroecosystem.

    PubMed

    Bobiwash, Kyle; Uriel, Yonathan; Elle, Elizabeth

    2018-02-09

    Highbush blueberry, Vaccinium corymbosum (Gray), production in British Columbia is dependent upon insect pollination for fruit yield with particular cultivars demonstrating low yields due to poor pollination. New managed species of pollinators are being developed to provide farmers with managed pollinator options beyond Apis mellifera (Linnaeus). Pollinators in highbush blueberry agricultural systems encounter a variety of nontarget floral resources that may affect the pollination received by the crop. Our study analyzed the differences in pollen foraging of honey bees and two species of managed bumblebees across nine farm sites. Corbicular pollen loads from pollen foraging workers were removed and identified to the lowest taxonomic level possible. Of the three managed pollinators, the corbicular pollen loads of Bombus huntii (Greene) contained the most blueberry pollen (52.1%), three times as much as the two other managed bee species. Fifteen morphotypes of pollen were identified from all foraging workers with Rosaceae being the most frequently gathered overall pollen type (n = 74). The noncrop pollen identified in our samples derived from plant species not common as weedy species in the agroecosystem suggesting that floral resource diversity outside of the farm boundaries is important to pollinators. The three managed species in our blueberry fields utilized floral resources differentially underscoring the importance of pollinator species' characteristics and large-scale floral resource landscape in developing new managed pollinators and pollination strategies. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Sorption of Lincomycin by Manure-Derived Biochars from Water

    PubMed Central

    Liu, Cheng-Hua; Chuang, Ya-Hui; Li, Hui; Teppen, Brian J.; Boyd, Stephen A.; Gonzalez, Javier M.; Johnston, Cliff T.; Lehmann, Johannes; Zhang, Wei

    2018-01-01

    The presence of antibiotics in agroecosystems raises concerns about the proliferation of antibiotic-resistant bacteria and adverse effects to human health. Soil amendment with biochars pyrolized from manures may be a win-win strategy for novel manure management and antibiotics abatement. In this study, lincomycin sorption by manure-derived biochars was examined using batch sorption experiments. Lincomycin sorption was characterized by two-stage kinetics with fast sorption reaching quasi-equilibrium in the first 2 d, followed by slow sorption over 180 d. The fast sorption was primarily attributed to surface adsorption, whereas the long-term slow sorption was controlled by slow diffusion of lincomycin into biochar pore structures. Two-day sorption experiments were performed to explore effects of biochar particle size, solid/water ratio, solution pH, and ionic strength. Lincomycin sorption to biochars was greater at solution pH 6.0 to 7.5 below the dissociation constant of lincomycin (7.6) than at pH 9.9 to 10.4 above its dissociation constant. The enhanced lincomycin sorption at lower pH likely resulted from electrostatic attraction between the positively charged lincomycin and the negatively charged biochar surfaces. This was corroborated by the observation that lincomycin sorption decreased with increasing ionic strength at lower pH (6.7) but remained constant at higher pH (10). The long-term lincomycin sequestration by biochars was largely due to pore diffusion plausibly independent of solution pH and ionic composition. Therefore, manure-derived biochars had lasting lincomycin sequestration capacity, implying that biochar soil amendment could significantly affect the distribution, transport, and bioavailability of lincomycin in agroecosystems. PMID:27065399

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