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Sample records for agricultural field experiment

  1. Agricultural Education Early Field Experience through the Lens of the EFE Model

    ERIC Educational Resources Information Center

    Smalley, Scott W.; Retallick, Michael S.

    2012-01-01

    The purpose of this national study was to describe agricultural teacher education early field experience (EFE) practices using the EFE model. The population for this study was all agricultural education teacher preparation programs (N = 83) listed in the AAAE Directory of University Faculty in Agricultural Education. Data were collected via an…

  2. Engineering and agronomy aspects of a long-term precision agriculture field experiment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Much research has been conducted on specific precision agriculture tools and implementation strategies, but little has been reported on long-term evaluation of integrated precision agriculture field experiments. In 2004 our research team developed and initiated a multi-faceted “precision agriculture...

  3. Vegetation Water Content Mapping in a Diverse Agricultural Landscape: National Airborne Field Experiment 2006

    NASA Technical Reports Server (NTRS)

    Cosh, Michael H.; Jing Tao; Jackson, Thomas J.; McKee, Lynn; O'Neill, Peggy

    2011-01-01

    Mapping land cover and vegetation characteristics on a regional scale is critical to soil moisture retrieval using microwave remote sensing. In aircraft-based experiments such as the National Airborne Field Experiment 2006 (NAFE 06), it is challenging to provide accurate high resolution vegetation information, especially on a daily basis. A technique proposed in previous studies was adapted here to the heterogenous conditions encountered in NAFE 06, which included a hydrologically complex landscape consisting of both irrigated and dryland agriculture. Using field vegetation sampling and ground-based reflectance measurements, the knowledge base for relating the Normalized Difference Water Index (NDWI) and the vegetation water content was extended to a greater diversity of agricultural crops, which included dryland and irrigated wheat, alfalfa, and canola. Critical to the generation of vegetation water content maps, the land cover for this region was determined from satellite visible/infrared imagery and ground surveys with an accuracy of 95.5% and a kappa coefficient of 0.95. The vegetation water content was estimated with a root mean square error of 0.33 kg/sq m. The results of this investigation contribute to a more robust database of global vegetation water content observations and demonstrate that the approach can be applied with high accuracy. Keywords: Vegetation, field experimentation, thematic mapper, NDWI, agriculture.

  4. Revisiting Supervised Agricultural Experience.

    ERIC Educational Resources Information Center

    Camp, William G.; Clarke, Ariane; Fallon, Maureen

    2000-01-01

    A Delphi panel of 40 agricultural educators unanimously agreed that supervised agricultural experience should remain an integral component of the curriculum; a name change is not currently warranted. Categories recommended were agribusiness entrepreneurship, placement, production, research, directed school lab, communications, exploration, and…

  5. Field experiments to evaluate nitrate-leaching from drained agriculturally used areas

    NASA Astrophysics Data System (ADS)

    Bednorz, Denise; Tauchnitz, Nadine; Christen, Olaf; Rupp, Holger; Meissner, Ralph

    2016-04-01

    Agricultural land use is one of the main sources for diffuse nitrogen (N) inputs into surface- and groundwater. To fulfill the objectives of the European water protection policy it is mandatory to optimize agricultural management and to adopt it to site specific conditions. N present in soil is dominated by organic N, and after mineralization inorganic plant available N, obtaining the components ammonia and nitrate (NO3-N). In the environment, NO3-N occurs as the negatively charged ion NO3- which is generally solved. Thus, NO3-N is the major N-species in waters, whereas its transport is directly influenced by the flow regime. In dependence of soil type and meteorological conditions, subsurface drainage was often installed to prevent water logged zones as a requirement for agricultural use. But drainage systems were often discussed as one of the main sources for NO3-N inputs into surface water due to temporary high discharge rates and short residence time of soil water resulting in limited conditions for NO3-N degradation via denitrification. In the study presented herein, two adjacent tile-drained agriculturally used areas with adjusted agronomic conditions but different soil properties were investigated regarding their flow regime and their N-kinetic from 11/1/2013 until 10/31/2015. Both fields obtained the same size and drainage network (drain depth 0.8 m, gab distance 10 m). Field I was influenced by confined groundwater conditions due to an alternating strata of sandy and loamy layers. Field II was impermeable from a depth of one meter, showing a backwater influenced flow regime. The temporal course of soil moisture (35, 60 and 85 cm depth), drain rate as well as ground- and backwater head was registered continuously at both sites. Furthermore NH4-N- and NO3-N-concentrations (cNO3-N) in each compartment were measured. The experimental results showed that field I revealed significantly lower discharged drain rates and NO3-N-loads (17.1 mm and 2.5 kg N

  6. Effects of agricultural fungicides on microorganisms associated with floral nectar: susceptibility assays and field experiments.

    PubMed

    Bartlewicz, Jacek; Pozo, María I; Honnay, Olivier; Lievens, Bart; Jacquemyn, Hans

    2016-10-01

    Pesticides have become an inseparable element of agricultural intensification. While the direct impact of pesticides on non-target organisms, such as pollinators, has recently received much attention, less consideration has been given to the microorganisms that are associated with them. Specialist yeasts and bacteria are known to commonly inhabit floral nectar and change its chemical characteristics in numerous ways, possibly influencing pollinator attraction. In this study, we investigated the in vitro susceptibility of nectar yeasts Metschnikowia gruessi, Metschnikowia reukaufii, and Candida bombi to six widely used agricultural fungicides (prothioconazole, tebuconazole, azoxystrobin, fenamidone, boscalid, and fluopyram). Next, a commercial antifungal mixture containing tebuconazole and trifloxystrobin was applied to natural populations of the plant Linaria vulgaris and the occurrence, abundance, and diversity of nectar-inhabiting yeasts and bacteria was compared between treated and untreated plants. The results showed that prothioconazole and tebuconazole were highly toxic to nectar yeasts, inhibiting their growth at concentrations varying between 0.06 and 0.5 mg/L. Azoxystrobin, fenamidone, boscalid, and fluopyram on the other hand exhibited considerably lower toxicity, inhibiting yeast growth at concentrations between 1 and 32 mg/L or in many cases not inhibiting microbial growth at all. The application of the antifungal mixture in natural plant populations resulted in a significant decrease in the occurrence and abundance of yeasts in individual flowers, but this did not translate into noticeable changes in bacterial incidence and abundance. Yeast and bacterial species richness and distribution did not also differ between treated and untreated plants. We conclude that the application of fungicides may have negative effects on the abundance of nectar yeasts in floral nectar. The consequences of these effects on plant pollination processes in agricultural

  7. Predation by carabid beetles on the invasive slug Arion vulgaris in an agricultural semi-field experiment.

    PubMed

    Pianezzola, E; Roth, S; Hatteland, B A

    2013-04-01

    Arion vulgaris Moquin-Tandon 1855 is one of the most important invasive species in Europe, affecting both biodiversity and agriculture. The species is spreading in many parts of Europe, inflicting severe damage to horticultural plants and cultivated crops partly due to a lack of satisfactory and effective management solutions. Molluscicides have traditionally been used to manage slug densities, although the effects are variable and some have severe side-effects on other biota. Thus, there is a need to explore potential alternatives such as biological control. The nematode Phasmarhabditis hermaphrodita is the only biological agent that has been applied commercially so far. However, other biological control agents such as carabid beetles have also been found to be promising. In addition, some carabid species have been shown to feed on A. vulgaris in the field as well as in the laboratory. Two species in particular have been found to be important predators of A. vulgaris, and these species are also common in agricultural environments: Pterostichus melanarius and Carabus nemoralis. This study is the first to use semi-field experiments in a strawberry field, manipulating densities, to investigate how P. melanarius and C. nemoralis affect densities of A. vulgaris eggs and juveniles, respectively. Gut contents of C. nemoralis were analysed using multiplex PCR methods to detect DNA of juvenile slugs. Results show that both P. melanarius and C. nemoralis significantly affect densities of slug eggs and juvenile slugs under semi-field conditions and that C. nemoralis seems to prefer slugs smaller than one gram. Carabus nemoralis seems to be especially promising in reducing densities of A. vulgaris, and future studies should investigate the potential of using this species as a biological control agent.

  8. Nutrient uptake by agricultural crops from biochar-amended soils: results from two field experiments in Austria

    NASA Astrophysics Data System (ADS)

    Karer, Jasmin; Zehetner, Franz; Kloss, Stefanie; Wimmer, Bernhard; Soja, Gerhard

    2013-04-01

    The use of biochar as soil amendment is considered as a promising agricultural soil management technique, combining carbon sequestration and soil fertility improvements. These expectations are largely founded on positive experiences with biochar applications to impoverished or degraded tropical soils. The validity of these results for soils in temperate climates needs confirmation from field experiments with typical soils representative for intensive agricultural production areas. Frequently biochar is mixed with other organic additives like compost. As these two materials interact with each other and each one may vary considerably in its basic characteristics, it is difficult to attribute the effects of the combined additive to one of its components and to a specific physico-chemical parameter. Therefore investigations of the amendment efficacy require the study of the pure components to characterize their specific behavior in soil. This is especially important for adsorption behavior of biochar for macro- and micronutrients because in soil there are multiple nutrient sinks that compete with plant roots for vital elements. Therefore this contribution presents results from a field amendment study with pure biochar that had the objective to characterize the macro- and microelement uptake of crops from different soils in two typical Austrian areas of agricultural production. At two locations in North and South-East Austria, two identical field experiments on different soils (Chernozem and Cambisol) were installed in 2011 with varying biochar additions (0, 30 and 90 t/ha) and two nitrogen levels. The biochar was a product from slow pyrolysis of wood (SC Romchar SRL). During the installation of the experiments, the biochar fraction of <2 mm was mixed with surface soil to a depth of 15 cm in plots of 33 m2 each (n=4). Barley (at the Chernozem soil) and maize (at the Cambisol) were cultivated according to standard agricultural practices. The highest crop yields at both

  9. Effects of agricultural tillage practise on green house gas balance of an arable soil in a long term field experiment

    NASA Astrophysics Data System (ADS)

    Munch, Jean Charles; Schilling, Rolf; Ruth, Bernhard; Fuss, Roland

    2010-05-01

    Soils are an important part of the global carbon cycle. A large proportion of global carbon dioxide (CO2) emissions is released from soils, though carbon sequestration occurs. Nitrous oxide (N2O) emissions of soils are also believed to contribute significantly to the green house effect as well as the stratospheric ozone depletion. An important source of N2O emissions is denitrification of nitrate from nitrogen fertilized soils. Although it is desirable to minimize these emissions while maintaining high crop yields it is still poorly understood how green house gas emissions may be steered by agricultural management practise, i.e. tillage and fertilization systems . In an ongoing long term field experiment at the research farm Scheyern, Bavaria, a arable field with one homogenous soil formation was transformed into plots in a randomized design 14 years ago. Since then, they are managed using conventional tillage (CT) and no tillage (NT) as well as low and high fertilization. A conventional crop rotation is maintained on the field. Starting 2007, CO2 and N2O emissions were monitored continuously for 2.5 years. Furthermore water content, temperature and redox potential were measured in-situ as they are major factors on microbial activity and denitrification. Soil was sampled from the Ap horizons of the plots about twice a month and extracts from these soil samples were analyzed for dissolved organic carbon (DOC), ammonium, nitrate/nitrite, and dissolved organic nitrogen (DON). According to the results soil density and hydrology are clearly affected by tillage practise. DOC is more affected by tillage while concentration of nitrogen species is controlled mainly by fertilization. There are distinct differences in redox potential between CT and NT plots with CT plots having more anaerobic periods. CO2 and N2O emissions exhibit a clear seasonal pattern and are affected by both tillage system and fertilization

  10. Agricultural fields, Khartoum, Sudan, Africa

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This herringbone pattern of irrigated agricultural fields near Khartoum, Sudan (14.5N, 33.5E) is very distinctive in both size and shape. The region contains thousands of these rectangular fields bounded by canals which carry water from both the White and Blue Nile Rivers. A crop rotation system is used so that some fields are in cotton, millit, sorghum or fallow to conserve moisture and control weeds and insects. See also STS049-96-003.

  11. Field spectroscopy of agricultural crops

    NASA Technical Reports Server (NTRS)

    Bauer, M. E.; Daughtry, C. S. T.; Biehl, L. L.; Kanemasu, E. T.; Hall, F. G.

    1986-01-01

    The development of the full potential of multispectral data acquired from satellites, requires quantitative knowledge, and physical models of the spectral properties of specific earth surface features. Knowledge of the relationships between spectral-radiometric characteristics and important biophysical parameters of agricultural crops and soils can best be obtained by carefully controlled studies of fields or plots. It is important to select plots where data describing the agronomic-biophysical properties of the crop canopies and soil background are attainable, taking into account also the feasibility of frequent timely calibrated spectral measurements. The term 'field spectroscopy' is employed for this research. The present paper is concerned with field research which was sponsored by NASA as part of the AgRISTARS Supporting Research Project. Attention is given to field research objectives, field research instrumentation, measurement procedures, spectral-temporal profile modeling, and the effects of cultural and environmental factors on crop reflectance.

  12. Dissipation of chlorothalonil, chlorpyrifos, and profenofos in a Malaysian agricultural soil: a comparison between the field experiment and simulation by the PERSIST model.

    PubMed

    Ismail, B S; Ngan, C K

    2005-01-01

    A comparison of dissipation of chlorothalonil, chlorpyrifos, and profenofos in a Malaysian agricultural soil between the field experiment and simulation by the PERSIST model was studied. A plot of sweet pea (Pisum sativum) from a farm in the Cameron Highlands was selected for the field experiment. The plot was treated with chlorothalonil, chlorpyrifos, and profenofos. Core soil collection was conducted according to the sampling schedule. Residues of the three pesticides were analyzed in the laboratory. Simulations of the three pesticides' persistency were also conducted using a computer-run software PERSIST. Generally, predicted data obtained using PERSIST were found to be high for the three pesticides except for one field measurement of chlorpyrifos. The predicted data for profenofos, which is the most mobile of the three pesticides tested, was not well matched with the observed data compared to chlorothalonil and chlorpyrifos. PMID:15825685

  13. Field experiments of Controlled Drainage of agricultural clay soils show positive effects on water quantity (retention, runoff) and water quality (nitrate leaching).

    NASA Astrophysics Data System (ADS)

    schipper, peter; stuyt, lodewijk; straat, van der, andre; schans, van der, martin

    2014-05-01

    Despite best management practices, agriculture is still facing major challenges to reduce nutrients leaching to the aquatic environment. In deltas, most of total nutrient losses from artificially drained agricultural soils are discharged via drains. Controlled drainage is a promising measure to prevent drainage of valuable nutrients, improve water quality and agricultural yield and adapt to climate change (reduce peak runoff, manage water scarcity and drought). In The Netherlands, this technique has attracted much attention by water managers and farmers alike, yet field studies to determine the expected (positive) effects for Dutch conditions were scarce. Recently, a field experiment was set up on clay soils. Research questions were: how does controlled, subsurface drainage perform on clay soils? Will deeper tile drains function just as well? What are the effects on drain water quality (especially with respect to nitrogen and salt) and crop yield? An agricultural field on clay soils was used to test different tile drainage configurations. Four types of tile drainage systems were installed, all in duplicate: eight plots in total. Each plot has its own outlet to a control box, where equipment was installed to control drain discharge and to measure the flow, concentrations of macro-ions, pH, nitrogen, N-isotopes and heavy metals. In each plot, groundwater observation wells and suction cups are installed in the saturated and vadose zones, at different depths, and crop yield is determined. Four plots discharge into a hydrologic isolated ditch, enabling the determination of water- and nutrient balances. Automatic drain water samplers and innovative nitrate sensors were installed in four plots. These enable identification and unravelling so-called first flush effects (changes in concentrations after a storm event). Water-, chloride- and nitrogen balances have been set up, and the interaction between groundwater and surface water has been quantified. The hydrological

  14. Thermal microwave emissions from vegetated fields: A comparison between theory and experiment. [Agricultural Research Center, Beltsville, MD.

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Shiue, J.; Chuang, S. L.; Dombrowski, M.

    1980-01-01

    The radiometric measurements over bare field and fields covered with grass, soybean, corn, and alfalfa were made with 1.4 GHz and 5 GHz microwave radiometers during August - October 1978. The measured results are compared with radiative transfer theory treating the vegetated fields as a two layer random medium. It is found that the presence of a vegetation cover generally gives a higher brightness temperature T(B) than that expected from a bare soil. The amount of this T(B) excess increases in the vegetation biomass and in the frequency of the observed radiation. The results of radiative transfer calculations generally match well with the experimental data, however, a detailed analysis also strongly suggests the need of incorporating soil surface roughness effect into the radiative transfer theory in order to better interpret the experimental data.

  15. MOBILIZATION AND TRANSPORT OF SOIL PARTICLES DURING INFILTRATION EXPERIMENTS IN AN AGRICULTURAL FIELD, SHENANDOAH VALLEY, VIRGINIA. (R824772)

    EPA Science Inventory

    Evidence that fine particles mobilized and transported in
    soils and aquifers can have a profound influence on
    contaminant migration has spawned much interest recently
    in understanding colloid transport in natural materials.
    Repeated infiltration experiments on an i...

  16. A field experiment with variable-suction multi-compartment samplers to measure the spatio-temporal distribution of solute leaching in an agricultural soil.

    PubMed

    Bloem, E; Hogervorst, F A N; de Rooij, G H

    2009-04-01

    Solutes spread out in time and space as they move downwards from the soil surface with infiltrating water. Solute monitoring in the field is often limited to observations of resident concentrations, while flux concentrations govern the movement of solutes in soils. A recently developed multi-compartment sampler is capable of measuring fluxes at a high spatial resolution with minimal disturbance of the local pressure head field. The objective of this paper is to use this sampler to quantify the spatial and temporal variation of solute leaching below the root zone in an agricultural field under natural rainfall in winter and spring. We placed two samplers at 31 and 25 cm depth in an agricultural field, leaving the soil above undisturbed. Each sampler contained 100 separate cells of 31x31 mm. Water fluxes were measured every 5 min for each cell. We monitored leaching of a chloride pulse under natural rainfall by frequently extracting the collected leachate while leaving the samplers buried in situ. This experiment was followed by a dye tracer experiment. This setting yielded information that widely surpassed the information that can be provided by separate anionic and dye tracer trials, and solute transport monitoring by coring or suction cups. The detailed information provided by the samplers showed that percolation at the sampling depth started much faster (approximately 3 h after the start of rainfall) in initially wet soil (pressure head above -65 cm) than in drier soil (more than 14 h at pressure heads below -80 cm). At any time, 25% of the drainage passed through 5-6% of the sampled area, reflecting the effect of heterogeneity on the flow paths. The amount of solute carried by individual cells varied over four orders of magnitude. The lateral concentration differences were limited though. This suggests a convective-dispersive regime despite the short vertical travel distance. On the other hand, the dilution index indicates a slight tendency towards stochastic

  17. Charting the history of agricultural experiments.

    PubMed

    Parolini, Giuditta

    2015-09-01

    Agricultural experimentation is a world in constant evolution, spanning multiple scientific domains and affecting society at large. Even though the questions underpinning agricultural experiments remain largely the same, the instruments and practices for answering them have changed constantly during the twentieth century with the advent of new disciplines like molecular biology, genomics, statistics, and computing. Charting this evolving reality requires a mapping of the affinities and antinomies at work within the realm of agricultural research, and a consideration of the practices, tools and social and political structures in which agricultural experiments are grounded. Three main questions will be addressed to provide an overview of the complex world of agricultural research investigated by the special issue: What is an agricultural experiment? Who is an experimenter in agriculture? Where do agricultural experiments take place? It will become apparent that agricultural experiments have a wide relevance for human development as they touch upon concerns related to human health and nutrition, contribute to policy discussions, and can affect the social and political structures in which farming is embedded. PMID:26205202

  18. Exploring Principals' Perceptions of Supervised Agricultural Experience

    ERIC Educational Resources Information Center

    Rayfield, John; Wilson, Elizabeth

    2009-01-01

    This study explored the perceptions of principals at high schools with agricultural education programs in regard to Supervised Agricultural Experience (SAE). There is evidence that suggests that high school principals' attitudes may both directly and indirectly affect factors that influence school climate and student achievement. In this study,…

  19. 7 CFR 3434.5 - Agriculture-related fields.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Agriculture-related fields. 3434.5 Section 3434.5 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND AGRICULTURE HISPANIC-SERVING AGRICULTURAL COLLEGES AND UNIVERSITIES CERTIFICATION PROCESS § 3434.5...

  20. 7 CFR 3434.5 - Agriculture-related fields.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Agriculture-related fields. 3434.5 Section 3434.5 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND AGRICULTURE HISPANIC-SERVING AGRICULTURAL COLLEGES AND UNIVERSITIES CERTIFICATION PROCESS § 3434.5...

  1. Field and microcosm experiments to evaluate the effects of agricultural Cu treatment on the density and genetic structure of microbial communities in two different soils.

    PubMed

    Ranjard, Lionel; Echairi, Abdelwahad; Nowak, Virginie; Lejon, David P H; Nouaïm, Rachida; Chaussod, Rémi

    2006-11-01

    The effects of Cu amendment on indigenous soil microorganisms were investigated in two soils, a calcareous silty clay (Ep) and a sandy soil (Au), by means of a 1-year field experiment and a two-month microcosm incubation. Cu was added as 'Bordeaux mixture' [CuSO(4), Ca(OH)(2)] at the standard rate used in viticulture (B1=16 kg Cu kg(-1) soil) and at a higher level of contamination (B3=48 kg Cu ha(-1) soil). More extractable Cu was observed in sandy soil (Au) than in silty soil (Ep). Furthermore, total Cu and Cu-EDTA declined with time in Au soil, whereas they remained stable in Ep soil. Quantitative modifications of the microflora were assessed by C-biomass measurements and qualitative modifications were assessed by the characterization of the genetic structure of bacterial and fungal communities from DNA directly extracted from the soil, using B- and F-ARISA (bacterial and fungal automated ribosomal intergenic spacer analysis). In the field study, no significant modifications were observed in C-biomass whereas microcosm incubation showed a decrease in B3 contamination only. ARISA fingerprinting showed slight but significant modifications of bacterial and fungal communities in field and microcosm incubation. These modifications were transient in all cases, suggesting a short-term effect of Cu stress. Microcosm experiments detected the microbial community modifications with greater precision in the short-term, while field experiments showed that the biological effects of Cu contamination may be overcome or hidden by pedo-climatic variations. PMID:17064271

  2. Field and microcosm experiments to evaluate the effects of agricultural Cu treatment on the density and genetic structure of microbial communities in two different soils.

    PubMed

    Ranjard, Lionel; Echairi, Abdelwahad; Nowak, Virginie; Lejon, David P H; Nouaïm, Rachida; Chaussod, Rémi

    2006-11-01

    The effects of Cu amendment on indigenous soil microorganisms were investigated in two soils, a calcareous silty clay (Ep) and a sandy soil (Au), by means of a 1-year field experiment and a two-month microcosm incubation. Cu was added as 'Bordeaux mixture' [CuSO(4), Ca(OH)(2)] at the standard rate used in viticulture (B1=16 kg Cu kg(-1) soil) and at a higher level of contamination (B3=48 kg Cu ha(-1) soil). More extractable Cu was observed in sandy soil (Au) than in silty soil (Ep). Furthermore, total Cu and Cu-EDTA declined with time in Au soil, whereas they remained stable in Ep soil. Quantitative modifications of the microflora were assessed by C-biomass measurements and qualitative modifications were assessed by the characterization of the genetic structure of bacterial and fungal communities from DNA directly extracted from the soil, using B- and F-ARISA (bacterial and fungal automated ribosomal intergenic spacer analysis). In the field study, no significant modifications were observed in C-biomass whereas microcosm incubation showed a decrease in B3 contamination only. ARISA fingerprinting showed slight but significant modifications of bacterial and fungal communities in field and microcosm incubation. These modifications were transient in all cases, suggesting a short-term effect of Cu stress. Microcosm experiments detected the microbial community modifications with greater precision in the short-term, while field experiments showed that the biological effects of Cu contamination may be overcome or hidden by pedo-climatic variations.

  3. Wake field acceleration experiments

    SciTech Connect

    Simpson, J.D.

    1988-01-01

    Where and how will wake field acceleration devices find use for other than, possibly, accelerators for high energy physics. I don't know that this can be responsibly answered at this time. What I can do is describe some recent results from an ongoing experimental program at Argonne which support the idea that wake field techniques and devices are potentially important for future accelerators. Perhaps this will spawn expanded interest and even new ideas for the use of this new technology. The Argonne program, and in particular the Advanced Accelerator Test Facility (AATF), has been reported in several fairly recent papers and reports. But because this is a substantially new audience for the subject, I will include a brief review of the program and the facility before describing experiments. 10 refs., 7 figs.

  4. Agricultural Experiment Stations and Branch Stations in the United States

    ERIC Educational Resources Information Center

    Pearson, Calvin H.; Atucha, Amaya

    2015-01-01

    In 1887, Congress passed the Hatch Act, which formally established and provided a funding mechanism for agricultural experiment stations in each state and territory in the United States. The main purpose of agricultural experiment stations is to conduct agricultural research to meet the needs of the citizens of the United States. The objective of…

  5. Sustainable agriculture and nitrogen reduction: an open field experiment using natural zeolitites in silty-clay reclaimed soil at Codigoro (Po River Delta, Ferrara, Italy)

    NASA Astrophysics Data System (ADS)

    Faccini, Barbara; Di Giuseppe, Dario; Mastrocicco, Micòl; Coltorti, Massimo; Colombani, Nicolò; Ferretti, Giacomo

    2014-05-01

    Following the guidelines of Nitrate and Water Framework Directives (91/676/CEE, 200/60/CE) an innovative integrated zeolitite cycle is being tested on a reclaimed clayey-silt soil in the Po Delta area (Ferrara Province, Italy), in the framework of the EU-funded ZeoLIFE project (LIFE+10 ENV/IT/000321). Natural zeolitites are pyroclastic rocks containing more than 50% of zeolites, a kind of hydrous minerals with peculiar physical and chemical properties, like high and selective cation exchange capacity (CEC), molecular adsorption and reversible dehydration. Zeolitites can trap NH4+ from solutions and release it gradually to the plant roots once they have been mixed in agricultural soils, allowing both fertilization and irrigation reduction and improvement of the yield. The fertilization reduction can result in a decrease of the nitrate content in groundwater and surface waters, ultimately leading to a mitigation of nutrient excess in the environment. Similarly, reduction of irrigation water means a minor exploitation of the water resource. The selected material used in the project is a chabazite zeolitite coming from a quarry near Sorano in Central Italy (Bolsena volcanic district). The open-field experimentation foresees two year of cultivation. A surface of about 6 ha has been divided into six parcels: three control parcels are cultivated and irrigated in traditional way; two parcels have been added with coarse-grained (ø = 3- 6 mm) natural zeolitite at different zeolitite/soil ratios (5 kg/m2 and 15 kg/m2) and one has been mixed with fine-grained (ø < 3 mm) NH4+-charged zeolitite at 10 kg/m2. Zeolitite/soil ratios have been determined upon a series of greenhouse tests, and the ammonium enriched material is obtained by cation exchange with swine manure in a specifically conceived prototype. The environmental quality of soil and water in each parcel is monitored by periodic soil, groundwater and porewater analyses. Soil EC, temperature and volumetric water content

  6. Career Development, Supervised Agricultural Experience, and FFA. The Connecticut Vocational Agriculture Education Curriculum.

    ERIC Educational Resources Information Center

    Mannebach, Alfred J.; And Others

    This curriculum guide was developed to help teachers and administrators in Connecticut Regional Vocational Agriculture Centers to update and upgrade their vocational agriculture curriculum in the areas of career development, supervised agricultural experience (SAE), and Future Farmers of America (FFA). The curriculum incorporates the competencies…

  7. Zoning of agricultural field using a fuzzy indicators model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zoning of agricultural fields is an important task for utilization of precision farming technology. One method for deciding how to subdivide a field into a few relatively homogenous zones is using applications of fuzzy sets theory. Data collected from a precision agriculture study in central Texas...

  8. Field test experience

    NASA Technical Reports Server (NTRS)

    Weaver, R. W.

    1983-01-01

    As a part of the Flat-Plate Solar Array Project (FSA), a field-test program was developed to obtain solar photovoltaic (PV) module performance and endurance data. These data are used to identify the specific characteristics of module designs under various environmental conditions. The information obtained from field testing is useful to all participants in the National Photovoltaics Program, from the research planner to the life-cycle cost analyst.

  9. Classification and soil moisture determination of agricultural fields

    NASA Technical Reports Server (NTRS)

    Vandenbroek, A. C.; Groot, J. S.

    1993-01-01

    During the Mac-Europe campaign of 1991 several SAR (Synthetic Aperature Radar) experiments were carried out in the Flevoland test area in the Netherlands. The test site consists of a forested and an agricultural area with more than 15 different crop types. The experiments took place in June and July (mid to late growing season). The area was monitored by the spaceborne C-band VV polarized ERS-1, the Dutch airborne PHARS with similar frequency and polarization and the three-frequency PP-, L-, and C-band) polarimetric AIRSAR system of NASA/JPL. The last system passed over on June 15, 3, 12, and 28. The last two dates coincided with the overpasses of the PHARS and the ERS-1. Comparison of the results showed that backscattering coefficients from the three systems agree quite well. In this paper we present the results of a study of crop type classification (section 2) and soil moisture determination in the agricultural area (section 3). For these studies we used field averaged Stokes matrices extracted from the AIRSAR data (processor version 3.55 or 3.56).

  10. Polar Magnetic Field Experiment

    NASA Technical Reports Server (NTRS)

    Russell, C. T.

    1999-01-01

    This grant covers the initial data reduction and analysis of the magnetic field measurements of the Polar spacecraft. At this writing data for the first three years of the mission have been processed and deposited in the key parameter database. These data are also available in a variety of time resolutions and coordinate systems via a webserver at UCLA that provides both plots and digital data. The flight software has twice been reprogrammed: once to remove a glitch in the data where there were rare collisions between commands in the central processing unit and once to provide burst mode data at 100 samples per second on a regular basis. The instrument continues to function as described in the instrument paper (1.1 in the bibliography attached below). The early observations were compared with observations on the same field lines at lower altitude. The polar magnetic measurements also proved to be most useful for testing the accuracy of MHD models. WE also made important contributions to study of waves and turbulence.

  11. Exploring the Paradox of Supervised Agricultural Experience Programs in Agricultural Education

    ERIC Educational Resources Information Center

    Wilson, Elizabeth B.; Moore, Gary E.

    2007-01-01

    Agricultural teachers in North Carolina were surveyed to assess their attitudes toward Supervised Agricultural Experience (SAE) and to identify barriers to implementation of SAE in their schools. The teachers gave the politically correct answers about why SAE was important. The teachers indicated that SAE was important (8.46 on a 10 point scale)…

  12. Environmental Biology: A Field Experience.

    ERIC Educational Resources Information Center

    Grove, Jim

    1984-01-01

    Recounts experiences of an environmental biology class, highlighting the eight-day field trip that is the culmination of the course. Describes activities during the bus trip, a two-day canoe trip, and field work at the Ozark Underground Laboratory and Blanchard Springs Caverns. Also discusses the field journal and final examination. (JM)

  13. Supervised Agricultural Experience: An Examination of Student Knowledge and Participation

    ERIC Educational Resources Information Center

    Lewis, Lauren J.; Rayfield, John; Moore, Lori L.

    2012-01-01

    The purpose of this study was to investigate student Supervised Agricultural Experience (SAE) knowledge and participation. This descriptive study was conducted in 120 randomly selected agricultural education programs throughout four purposively selected states representative of the National FFA regions. Students completed a questionnaire assessing…

  14. Benefits of Supervised Agricultural Experience Programs: A Synthesis of Research.

    ERIC Educational Resources Information Center

    Williams, David L.; Dyer, James E.

    1997-01-01

    A review of literature from 1964 to 1993 identified the benefits of supervised agricultural experience (SAE) programs, including agriculture knowledge and positive work attitudes. Classroom, SAE, and Future Farmers of America complemented each other. The research base is state specific and fragmented and lacks cohesiveness. (SK)

  15. Human Nutrition Research Conducted at State Agricultural Experiment Stations and 1890/Tuskegee Agricultural Research Programs.

    ERIC Educational Resources Information Center

    Driskell, Judy A.; Myers, John R.

    1989-01-01

    Cooperative State Research Service-administered and state-appropriated State Agriculture Experiment Station funds for human nutrition research increased about two-fold from FY70-FY86, while the percentage of budget expended for this research decreased. (JOW)

  16. Field potential soil variability index to identify precision agriculture opportunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Precision agriculture (PA) technologies used for identifying and managing within-field variability are not widely used despite decades of advancement. Technological innovations in agronomic tools, such as canopy reflectance or electrical conductivity sensors, have created opportunities to achieve a ...

  17. Fungal biology and agriculture: revisiting the field

    USGS Publications Warehouse

    Yarden, O.; Ebbole, D.J.; Freeman, S.; Rodriguez, R.J.; Dickman, M. B.

    2003-01-01

    Plant pathology has made significant progress over the years, a process that involved overcoming a variety of conceptual and technological hurdles. Descriptive mycology and the advent of chemical plant-disease management have been followed by biochemical and physiological studies of fungi and their hosts. The later establishment of biochemical genetics along with the introduction of DNA-mediated transformation have set the stage for dissection of gene function and advances in our understanding of fungal cell biology and plant-fungus interactions. Currently, with the advent of high-throughput technologies, we have the capacity to acquire vast data sets that have direct relevance to the numerous subdisciplines within fungal biology and pathology. These data provide unique opportunities for basic research and for engineering solutions to important agricultural problems. However, we also are faced with the challenge of data organization and mining to analyze the relationships between fungal and plant genomes and to elucidate the physiological function of pertinent DNA sequences. We present our perspective of fungal biology and agriculture, including administrative and political challenges to plant protection research.

  18. Fungal biology and agriculture: revisiting the field.

    PubMed

    Yarden, O; Ebbole, D J; Freeman, S; Rodriguez, R J; Dickman, M B

    2003-10-01

    Plant pathology has made significant progress over the years, a process that involved overcoming a variety of conceptual and technological hurdles. Descriptive mycology and the advent of chemical plant-disease management have been followed by biochemical and physiological studies of fungi and their hosts. The later establishment of biochemical genetics along with the introduction of DNA-mediated transformation have set the stage for dissection of gene function and advances in our understanding of fungal cell biology and plant-fungus interactions. Currently, with the advent of high-throughput technologies, we have the capacity to acquire vast data sets that have direct relevance to the numerous subdisciplines within fungal biology and pathology. These data provide unique opportunities for basic research and for engineering solutions to important agricultural problems. However, we also are faced with the challenge of data organization and mining to analyze the relationships between fungal and plant genomes and to elucidate the physiological function of pertinent DNA sequences. We present our perspective of fungal biology and agriculture, including administrative and political challenges to plant protection research.

  19. Family Oriented Geographic Field Experience.

    ERIC Educational Resources Information Center

    Williams, Karen Ann Lalk

    This paper describes a program of geographic education through field experience trips for family groups. Developed at Delta College in Michigan, the approach is unique because it emphasizes learning experiences for families rather than for individual students. The family is interpreted to include nuclear families, single-parent families with…

  20. Farmer Experience of Pluralistic Agricultural Extension, Malawi

    ERIC Educational Resources Information Center

    Chowa, Clodina; Garforth, Chris; Cardey, Sarah

    2013-01-01

    Purpose: Malawi's current extension policy supports pluralism and advocates responsiveness to farmer demand. We investigate whether smallholder farmers' experience supports the assumption that access to multiple service providers leads to extension and advisory services that respond to the needs of farmers. Design/methodology/approach: Within a…

  1. Experimental Evaluation of Field Trips on Instruction in Vocational Agriculture.

    ERIC Educational Resources Information Center

    McCaslin, Norval L.

    To determine the effect of field trips on student achievement in each of four subject matter areas in vocational agriculture, 12 schools offering approved programs were randomly selected and divided into a treatment group and a control group. Uniform teaching outlines and reference materials were provided to each group. While no field trips were…

  2. RECORDS OF SUPERVISED OCCUPATIONAL EXPERIENCE AND TRAINING IN VOCATIONAL AGRICULTURE.

    ERIC Educational Resources Information Center

    BURCROFF, WALTER; AND OTHERS

    HIGH SCHOOL VOCATIONAL AGRICULTURE STUDENTS MAY KEEP RECORDS OF THEIR SUPERVISED OCCUPATIONAL EXPERIENCE IN THIS RECORD BOOK. DEVELOPED BY A NATIONAL COMMITTEE OF TEACHERS, SUPERVISORS, AND TEACHER EDUCATORS, IT PROVIDES SPACE FOR RECORDING ESSENTIAL PLANS, PLACEMENT AGREEMENTS, MONTHLY WORK EXPERIENCES, FINANCIAL SUMMARIES, ACTIVITIES, AND…

  3. A contemporary decennial global sample of changing agricultural field sizes

    NASA Astrophysics Data System (ADS)

    White, E.; Roy, D. P.

    2011-12-01

    In the last several hundred years agriculture has caused significant human induced Land Cover Land Use Change (LCLUC) with dramatic cropland expansion and a marked increase in agricultural productivity. The size of agricultural fields is a fundamental description of rural landscapes and provides an insight into the drivers of rural LCLUC. Increasing field sizes cause a subsequent decrease in the number of fields and therefore decreased landscape spatial complexity with impacts on biodiversity, habitat, soil erosion, plant-pollinator interactions, diffusion of disease pathogens and pests, and loss or degradation in buffers to nutrient, herbicide and pesticide flows. In this study, globally distributed locations with significant contemporary field size change were selected guided by a global map of agricultural yield and literature review and were selected to be representative of different driving forces of field size change (associated with technological innovation, socio-economic conditions, government policy, historic patterns of land cover land use, and environmental setting). Seasonal Landsat data acquired on a decadal basis (for 1980, 1990, 2000 and 2010) were used to extract field boundaries and the temporal changes in field size quantified and their causes discussed.

  4. Student-Designed Field Experiences

    ERIC Educational Resources Information Center

    Permaul, Jane S.

    1976-01-01

    Opportunities should be made available for students to design their own field experiences with the use of learning contracts. This approach affords the student flexibility, emphasizes initiative and involvement, and aids in the resolution of the problem of school-to-work transition. (Author/JDS)

  5. Relationship of Supervised Agricultural Experience Program Participation and Student Achievement in Agricultural Education.

    ERIC Educational Resources Information Center

    Cheek, Jimmy G.; And Others

    1994-01-01

    Data from 537 high school students demonstrated the positive effect of participation in supervised agricultural experience (SAE) and Future Farmers of America (FFA) on agriscience achievement. FFA involvement and the scope of SAE were highly correlated. Student interest, socioeconomic status, and years of agriscience were related to achievement…

  6. Mojave remote sensing field experiment

    NASA Technical Reports Server (NTRS)

    Arvidson, Raymond E.; Petroy, S. B.; Plaut, J. J.; Shepard, Michael K.; Evans, D.; Farr, T.; Greeley, Ronald; Gaddis, L.; Lancaster, N.

    1991-01-01

    The Mojave Remote Sensing Field Experiment (MFE), conducted in June 1988, involved acquisition of Thermal Infrared Multispectral Scanner (TIMS); C, L, and P-band polarimetric radar (AIRSAR) data; and simultaneous field observations at the Pisgah and Cima volcanic fields, and Lavic and Silver Lake Playas, Mojave Desert, California. A LANDSAT Thematic Mapper (TM) scene is also included in the MFE archive. TM-based reflectance and TIMS-based emissivity surface spectra were extracted for selected surfaces. Radiative transfer procedures were used to model the atmosphere and surface simultaneously, with the constraint that the spectra must be consistent with field-based spectral observations. AIRSAR data were calibrated to backscatter cross sections using corner reflectors deployed at target sites. Analyses of MFE data focus on extraction of reflectance, emissivity, and cross section for lava flows of various ages and degradation states. Results have relevance for the evolution of volcanic plains on Venus and Mars.

  7. Illinois Occupational Skill Standards: Agricultural Laboratory and Field Technician Cluster.

    ERIC Educational Resources Information Center

    Illinois Occupational Skill Standards and Credentialing Council, Carbondale.

    These Illinois skill standards for the agricultural laboratory and field technician cluster are intended to serve as a guide to workforce preparation program providers as they define content for their programs and to employers as they establish the skills and standards necessary for job acquisition. They could also serve as a mechanism for…

  8. Lidar Based Particulate Flux Measurements of Agricultural Field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A three-wavelength portable scanning lidar system was developed to derive information on particulate spatial aerosol distribution over remote distances. The lidar system and retrieval approach has been tested during several field campaigns measuring agricultural emissions from a swine feeding operat...

  9. Supervision of Supervised Agricultural Experience Programs: A Synthesis of Research.

    ERIC Educational Resources Information Center

    Dyer, James E.; Williams, David L.

    1997-01-01

    A review of literature from 1964 to 1993 found that supervised agricultural experience (SAE) teachers, students, parents, and employers value the teachers' supervisory role. Implementation practices vary widely and there are no cumulative data to guide policies and standards for SAE supervision. (SK)

  10. Nuclide-migration field experiments

    SciTech Connect

    Erdal, B.R.; Wolfsberg, K.; Johnstone, J.K.; Erickson, K.L.; Friedman, A.M.; Fried, S.; Hines, J.J.

    1981-03-01

    When considering groundwater flow and radionuclide retention in the complex flow systems that can occur in geologic formations, one has a serious problem in determining if laboratory studies are being performed under conditions appropriate to natural systems. This document is the project plan for a program designed to begin to address these problems. The project is being carried out jointly by the Los Alamos National Laboratory, Sandia National Laboratories, and Argonne National Laboratory. The work has three principal objectives: (1) to develop the experimental, instrumental, and safety techniques necessary to conduct controlled, small-scale radionuclide migration field experiments, including those involving actinides; (2) to use these techniques to define radionuclide migration through rock by performing generic, at-depth experiments under closely monitored conditions; and (3) to determine whether available lithologic, geochemical, and hydrologic properties together with existing or developing transport models are sufficient and appropriate to describe real field conditions.

  11. Perception of Teachers of Agriculture about Supervised Agricultural Experience Programmes (SAEP) in Secondary Schools in Ekiti and Ondo States Nigeria

    ERIC Educational Resources Information Center

    Famiwole, Remi O.; Kolawole, E. B.

    2013-01-01

    The study investigated the perception of teachers of agriculture about Supervised Agricultural Experience Programmes (SAEP) in secondary schools in Ekiti and Ondo States. The population used for the study consisted of 520 teachers of agricultural science in all the secondary schools in Ekiti and Ondo States. The sample used for this study was 136…

  12. Parkinson's Disease Prevalence and Proximity to Agricultural Cultivated Fields.

    PubMed

    Yitshak Sade, Maayan; Zlotnik, Yair; Kloog, Itai; Novack, Victor; Peretz, Chava; Ifergane, Gal

    2015-01-01

    The risk for developing Parkinson's disease (PD) is a combination of multiple environmental and genetic factors. The Negev (Southern Israel) contains approximately 252.5 km(2) of agricultural cultivated fields (ACF). We aimed to estimate the prevalence and incidence of PD and to examine possible geographical clustering and associations with agricultural exposures. We screened all "Clalit" Health Services members in the Negev (70% of the population) between the years 2000 and 2012. Individual demographic, clinical, and medication prescription data were available. We used a refined medication tracer algorithm to identify PD patients. We used mixed Poisson models to calculate the smoothed standardized incidence rates (SIRs) for each locality. We identified ACF and calculate the size and distance of the fields from each locality. We identified 3,792 cases of PD. SIRs were higher than expected in Jewish rural localities (median SIR [95% CI]: 1.41 [1.28; 1.53] in 2001-2004, 1.62 [1.48; 1.76] in 2005-2008, and 1.57 [1.44; 1.80] in 2009-2012). Highest SIR was observed in localities located in proximity to large ACF (SIR 1.54, 95% CI 1.32; 1.79). In conclusion, in this population based study we found that PD SIRs were higher than expected in rural localities. Furthermore, it appears that proximity to ACF and the field size contribute to PD risk.

  13. Methane uptake in agricultural and old-field ecosystems

    SciTech Connect

    Reed, W.L.; Halstead, S.J.; Robertson, G.P. Michigan State Univ., East Lansing )

    1993-06-01

    Atmospheric methane (CH[sub 4]) concentrations are rising approximately 1% per year, with important consequences for the earth's radiation balance and tropospheric chemistry. Sources of this increase are not well known; recent evidence suggests that land conversion to agriculture may play some role in this increase if CH[sub 4] consumption in upland soils is suppressed by agronomic activities. We tested this hypothesis in a series of replicated agricultural and old-field communities at the KBS LTER site in southwest Michigan. We measured CH[sub 4] flux with static chambers in 6 different cropping systems (conventional till and no-till annual crops, ridge-till organic based crops, perennial crops) and in early successional and mid-succession (never tilled) old field communities. Chambers were sampled 17 times over the 1992 growing season and analyzed for CH[sub 4], N[sub 2]O, and CO[sub 2]. We found significant but highly variable CH[sub 4] uptake on some dates in all 8 ecosystem types, with most consistent consumption in the organic based crops and old-field communities.

  14. Agricultural fields, Khartoum, Sudan, Africa Description: This herringbone pattern of irrigated

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This herringbone pattern of irrigated agricultural fields near Khartoum, Sudan (14.5N, 33.5E) was imaged with infrared film as part an experiment to compare the merits of color film versus color infrared film. Color film presents the image as it appears to the eye whereas color infrared film has an excellent haze penetration and vegetation definition capability. See color film image STS049-77-072 for a detailed scene description.

  15. Tension on the Farm Fields: The Death of Traditional Agriculture?

    ERIC Educational Resources Information Center

    Oguamanam, Chidi

    2007-01-01

    Taking into account the historic transitions and progressions in agricultural science, this article examines the emergence of the phenomenon of agricultural biotechnology. It identifies pivotal sites of tension between agricultural biotechnology and alternative approaches to agriculture. The article identifies two distinct sources of contemporary…

  16. Perceptions Regarding Planning Activities and Supervision Strategies for Supervised Agricultural Experience Programs.

    ERIC Educational Resources Information Center

    Swortzel, Kirk A.

    1996-01-01

    Responses from 71% of 150 Tennessee agriculture teachers surveyed indicated that those teaching in multiple departments, subscribing to "Agricultural Education Magazine," and including supervised agricultural experiences (SAE) in grading were more positive about planning. Those not having agricultural education in high school, including SAE in…

  17. A Needs Assessment to Determine Knowledge and Ability of Egyptian Agricultural Technical School Teachers Related to Supervised Agricultural Experience

    ERIC Educational Resources Information Center

    Barrick, R. Kirby; Roberts, T. Grady; Samy, M. M.; Thoron, Andrew C.; Easterly, R. G., III

    2011-01-01

    This research was conducted approximately one year after Egyptian Agricultural Technical School (ATS) instructors attended workshops on integrating placement Supervised Agricultural Experience as an instructional tool in their programs. Following a year of implementation, the purpose of this study was to determine ATS teacher knowledge and ability…

  18. Value and Expectations of Supervised Agricultural Experiences as Expressed by Agriculture Instructors in Oklahoma Who Were Alternatively Certified

    ERIC Educational Resources Information Center

    Robinson, J. Shane; Haynes, J. Chris

    2011-01-01

    The purpose of this qualitative descriptive study was to determine the value and expectations for student participation in supervised agricultural experience (SAE) programs, as expressed by first-year, agricultural education teachers in Oklahoma who were alternatively certified. This study revealed that teachers in this study value the fact that…

  19. Methods for classification of agricultural fields in aerial sequences: a comparative study

    NASA Astrophysics Data System (ADS)

    Houkes, Zweitze; Chen, Haijun; Blacquiere, Jan-Friso

    1998-12-01

    A comparative study of a selection of classification methods for agricultural fields in sequences of aerial images is presented. The image sequences are acquired by an RGB-CCD video camera which is assumed to be on board of an airplane, moving linear over the scene. The objects in the scenes being considered are agricultural fields. The classes of agricultural fields to be distinguished are determined by the type of crop, e.g. potatoes, sugar beet, wheat, etc. In order to recognize and classify these fields obtained from the aerial sequences of images, a common approach is in the use of surface texture. Textural features are extracted from the images to effectively characterize the vegetation. Methods based on Circular Symmetric Auto-Regression, Co-Occurrence Matrix and Local Binary Patterns are selected for the comparative study. The experiments are carried out with image sequences taken from a scaled model of a landscape and a selection from the Brodatz set. A few training images are used to set up the model bases for the three methods. The methods are tested using the same regions from other images of the sequence, and other sequences of images of similar fields. Comparison fa the methods is based on the confusion matrix. Sensitivity to variations in flight direction, variations in altitude and luminance conditions are being considered.

  20. Searsville Sediment Experiment: What is the ideal agricultural soil?

    NASA Astrophysics Data System (ADS)

    Leal, J.; Lo, D.; Patel, N.; Gu, S.

    2014-12-01

    The purpose of this experiment is to decide whether or not the sediment located within Searsville Dam at the Jasper Ridge Biological Preserve is well suited for agricultural soil. By utilizing various combinations of sediment, farm soil, compost, and horse manure to grow basil plants, we underwent an exploratory study in order to better understand what type of materials and nutrients plants can best thrive within. Our general experiment protocol includes watering the crops with irrigation every day while young, and then limiting that water exposure to only Mondays, Wednesdays, and Fridays as they become more established. The basil is growing in pots filled with the different amounts of material, and are arranged randomly to prevent certain plants from getting more sunlight than others. The whole experiment plot is covered with a thin white fabric and secured with bricks and wood to keep out pests in the garden. In order to observe trends in the basil development, plant height and leaf number is recorded once every week. During the third week of the study we performed soil texture tests, and within the fourth week we calculated pH data. We discovered that the sediment our project focuses upon is 10-18% clay and 50% sand which categorizes it as loam, and the Stanford farm soil that serves as our control group contains 20-26% clay and 30% sand so it is a silt loam material. The pH tests also showed an average of 7.45 for sediment, 7.3 for farm soil, 7.85 for compost, and 7.65 for horse manure. By looking at all of the data recorded over the five-week time period, we have so far noticed that the 50% sediment and 50% horse manure combination consistently has the best height increase as well as leaf size and content. The 50% sediment and 50% compost mixture has also performed well in those terms, and is therefore a possibility for the best agricultural soil. However, future lab work conducted by Stanford students to examine the nutrient content of the basil tissue, along

  1. About soil cover heterogeneity of agricultural research stations' experimental fields

    NASA Astrophysics Data System (ADS)

    Rannik, Kaire; Kõlli, Raimo; Kukk, Liia

    2013-04-01

    Depending on local pedo-ecological conditions (topography, (geo) diversity of soil parent material, meteorological conditions) the patterns of soil cover and plant cover determined by soils are very diverse. Formed in the course of soil-plant mutual relationship, the natural ecosystems are always influenced to certain extent by the other local soil forming conditions or they are site specific. The agricultural land use or the formation of agro-ecosystems depends foremost on the suitability of soils for the cultivation of feed and food crops. As a rule, the most fertile or the best soils of the area, which do not present any or present as little as possible constraints for agricultural land use, are selected for this purpose. Compared with conventional field soils, the requirements for the experimental fields' soil cover quality are much higher. Experimental area soils and soil cover composition should correspond to local pedo-ecological conditions and, in addition to that, represent the soil types dominating in the region, whereas the fields should be as homogeneous as possible. The soil cover heterogeneity of seven arable land blocks of three research stations (Jõgeva, Kuusiku and Olustvere) was studied 1) by examining the large scale (1:10 000) digital soil map (available via the internet), and 2) by field researches using the transect method. The stages of soils litho-genetic and moisture heterogeneities were estimated by using the Estonian normal soils matrix, however, the heterogeneity of top- and subsoil texture by using the soil texture matrix. The quality and variability of experimental fields' soils humus status, was studied more thoroughly from the aspect of humus concentration (g kg-1), humus cover thickness (cm) and humus stocks (Mg ha-1). The soil cover of Jõgeva experimental area, which presents an accumulative drumlin landscape (formed during the last glacial period), consist from loamy Luvisols and associated to this Cambisols. In Kuusiku area

  2. Seed deterioration in flooded agricultural fields during winter

    USGS Publications Warehouse

    Nelms, C.O.; Twedt, D.J.

    1996-01-01

    We determined rate of seed deterioration for 3 crops (corn, rice, and soybean) and 8 weeds commonly found in agricultural fields and moist-soil management units in the Mississippi Alluvial Valley (MAV). The weeds were broadleaf signalgrass (Brachiaria platyphylla), junglerice barnyardgrass (Echinochloa colonum), morningglory (Ipomoea sp.), panic grass (Panicum sp.), bull paspalum (Paspalum boscianum), red rice (Oryza sativa), hemp sesbania (Sesbania exaltata), and bristlegrass (Setaria sp.). Weed seeds, except morningglory, deteriorated slower than corn and soybean, whereas rice decomposed slower than all weed seeds except red rice and bull paspalum. For land managers desiring to provide plant food for wintering waterfowl, rice is clearly the most persistent small grain crop in the MAV. Persistence of weed seeds under flooded conditions throughout winter makes them a cost-effective alternative to traditional crops on land managed for waterfowl.

  3. Agricultural Modernization and Economic Inequality: The Indian Experience

    ERIC Educational Resources Information Center

    Michie, Aruna Nayyar

    1978-01-01

    Argues that agriculture production in developing nations should be organized to ensure economic viability. Government policy must emphasize participants' productive capacities and integrate agricultural workers into the new organization of production. (Author/DB)

  4. Optimization of agricultural field workability predictions for improved risk management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Risks introduced by weather variability are key considerations in agricultural production. The sensitivity of agriculture to weather variability is of special concern in the face of climate change. In particular, the availability of workable days is an important consideration in agricultural practic...

  5. Field Experiments in Litter Control

    ERIC Educational Resources Information Center

    Finnie, William C.

    1973-01-01

    A series of urban and highway litter experiments in Richmond (Virginia), St. Louis, and Philadelphia indicated well-designed litter cans reduced littering about 15 percent along city streets and nearly 30 percent along highways. Also, the propensity to litter is critically affected by the characteristics of the individual and environmental…

  6. The Integration of Multimedia and Field Experience.

    ERIC Educational Resources Information Center

    Dawson, George

    A professor of science education at Florida State University shares his experiences with the growth of the field of environmental education and the problems inherent in trying to teach formal environmental education outdoors. Although field experience is best, it must be limited in most situations since logistics get in the way. Technology can…

  7. Family Oriented Field Experience in Geography.

    ERIC Educational Resources Information Center

    Williams, Karen A.

    A family-oriented geography field course about the southwestern United States was conducted in 1978 by a community college in Michigan (Delta College). Course activities took place in Colorado. The major purpose of the field experience was to offer learning experiences to family groups rather than to individual students. For purposes of the field…

  8. From theory to field experiments

    NASA Astrophysics Data System (ADS)

    de Vos, Bram

    2016-04-01

    Peter Raats' achievements in Haren (NL) 1986-1997 were based on a solid theoretical insight in hydrology and transport process in soil. However, Peter was also the driving force behind many experimental studies and applied research. This will be illustrated by a broad range of examples ranging from the dynamics of composting processes of organic material; modelling and monitoring nutrient leaching at field-scale; wind erosion; water and nutrient dynamics in horticultural production systems; oxygen diffusion in soils; and processes of water and nutrient uptake by plant roots. Peter's leadership led to may new approaches and the introduction of innovative measurement techniques in Dutch research; ranging from TDR to nutrient concentration measurements in closed fertigation systems. This presentation will give a brief overview how Peter's theoretical and mathematical insights accelerated this applied research.

  9. How to Thrive during Your Field Experiences

    ERIC Educational Resources Information Center

    Schaffer, Connie; Welsh, Kelly

    2014-01-01

    Field experiences, also referred to as practicums or clinical experiences, are part of every accredited teacher preparation program. These pre-student teaching experiences place future teachers in a preK-12 classroom where they have the opportunity not just to observe, but also to learn about teaching by interacting with teachers and students. The…

  10. Pesticide Leaching from Agricultural Fields with Ridges and Furrows

    PubMed Central

    Boesten, Jos J. T. I.

    2010-01-01

    In the evaluation of the risk of pesticide leaching to groundwater, the soil surface is usually assumed to be level, although important crops like potato are grown on ridges. A fraction of the water from rainfall and sprinkler irrigation may flow along the soil surface from the ridges to the furrows, thus bringing about an extra load of water and pesticide on the furrow soil. A survey of the literature reveals that surface-runoff from ridges to furrows is a well-known phenomenon but that hardly any data are available on the quantities of water and pesticide involved. On the basis of a field experiment with additional sprinkler irrigation, computer simulations were carried out with the Pesticide Emission Assessment at Regional and Local scales model for separate ridge and furrow systems in a humic sandy potato field. Breakthrough curves of bromide ion (as a tracer for water flow) and carbofuran (as example pesticide) were calculated for 1-m depth in the field. Bromide ion leached comparatively fast from the furrow system, while leaching from the ridge system was slower showing a maximum concentration of about half of that for the furrow system. Carbofuran breakthrough from the furrow system began about a month after application and increased steadily to substantial concentrations. Because the transport time of carbofuran in the ridge soil was much longer, no breakthrough occurred in the growing season. The maximum concentration of carbofuran leaching from the ridge–furrow field was computed to be a factor of six times as high as that computed for the corresponding level field. The study shows that the risk of leaching of pesticides via the furrow soil can be substantially higher than that via the corresponding level field soil. PMID:21076668

  11. Pesticide Leaching from Agricultural Fields with Ridges and Furrows.

    PubMed

    Leistra, Minze; Boesten, Jos J T I

    2010-11-01

    In the evaluation of the risk of pesticide leaching to groundwater, the soil surface is usually assumed to be level, although important crops like potato are grown on ridges. A fraction of the water from rainfall and sprinkler irrigation may flow along the soil surface from the ridges to the furrows, thus bringing about an extra load of water and pesticide on the furrow soil. A survey of the literature reveals that surface-runoff from ridges to furrows is a well-known phenomenon but that hardly any data are available on the quantities of water and pesticide involved. On the basis of a field experiment with additional sprinkler irrigation, computer simulations were carried out with the Pesticide Emission Assessment at Regional and Local scales model for separate ridge and furrow systems in a humic sandy potato field. Breakthrough curves of bromide ion (as a tracer for water flow) and carbofuran (as example pesticide) were calculated for 1-m depth in the field. Bromide ion leached comparatively fast from the furrow system, while leaching from the ridge system was slower showing a maximum concentration of about half of that for the furrow system. Carbofuran breakthrough from the furrow system began about a month after application and increased steadily to substantial concentrations. Because the transport time of carbofuran in the ridge soil was much longer, no breakthrough occurred in the growing season. The maximum concentration of carbofuran leaching from the ridge-furrow field was computed to be a factor of six times as high as that computed for the corresponding level field. The study shows that the risk of leaching of pesticides via the furrow soil can be substantially higher than that via the corresponding level field soil. PMID:21076668

  12. Indirect Reciprocity; A Field Experiment

    PubMed Central

    van Apeldoorn, Jacobien; Schram, Arthur

    2016-01-01

    Indirect reciprocity involves cooperative acts towards strangers, either in response to their kindness to third parties (downstream) or after receiving kindness from others oneself (upstream). It is considered to be important for the evolution of cooperative behavior amongst humans. Though it has been widely studied theoretically, the empirical evidence of indirect reciprocity has thus far been limited and based solely on behavior in laboratory experiments. We provide evidence from an online environment where members can repeatedly ask and offer services to each other, free of charge. For the purpose of this study we created several new member profiles, which differ only in terms of their serving history. We then sent out a large number of service requests to different members from all over the world. We observe that a service request is more likely to be rewarded for those with a profile history of offering the service (to third parties) in the past. This provides clear evidence of (downstream) indirect reciprocity. We find no support for upstream indirect reciprocity (in this case, rewarding the service request after having previously received the service from third parties), however. Our evidence of downstream indirect reciprocity cannot be attributed to reputational effects concerning one’s trustworthiness as a service user. PMID:27043712

  13. What Does an Inventory of Recent Innovation Experiences Tell Us about Agricultural Innovation in Africa?

    ERIC Educational Resources Information Center

    Triomphe, Bernard; Floquet, Anne; Kamau, Geoffrey; Letty, Brigid; Vodouhe, Simplice Davo; Ng'ang'a, Teresiah; Stevens, Joe; van den Berg, Jolanda; Selemna, Nour; Bridier, Bernard; Crane, Todd; Almekinders, Cornelia; Waters-Bayer, Ann; Hocde, Henri

    2013-01-01

    Purpose: Within the context of the European-funded JOLISAA project (JOint Learning in and about Innovation Systems in African Agriculture), an inventory of agricultural innovation experiences was made in Benin, Kenya and South Africa. The objective was to assess multi-stakeholder agricultural innovation processes involving smallholders. Approach:…

  14. Agricultural Production Experiences at School for the Urban Student.

    ERIC Educational Resources Information Center

    Dietz, Allen J.

    1980-01-01

    In vocational agriculture at Sycamore High School in Illinois, urban students start their vocational education with a basic understanding of production, which is the foundation for all agricultural industry. Future Farmers of America chapter-operated and school-owned facilities provide the resources to make these experiential programs possible.…

  15. Aproaches for mitigation of greenhouse gas emission from agricultural fields

    NASA Astrophysics Data System (ADS)

    Sudo, S.; Itoh, M.

    2009-12-01

    Percentage of atmospheric methane emitted form rice paddy is estimated at 60Tg/yr (20 - 100Tg/yr) which is near 10% of total global methane emission of 535Tg/yr (410 - 660Tg) (IPCC(1995), and which is near 30% of anthropogenic CH4 emission. Thus, mitigation of CH4 emission is required to be speed up. CH4 in paddy soil is emanated by the activities of anaerobic bacteria which is called methane producer through reduction of CO2 or decomposition of acetic acid, and it is transported to atmosphere through soil or paddy water surface. It is effective to control methane emission from rice paddy that period is prolonged on intermittent irrigation drainage, composted rice straw is incorporated as fertilizer instead of flesh one, or other. However, empirical approach of these kinds of experiments had not been sufficient because such a kind of experiment required significant times and efforts. In this study, we conducted demonstrative experiments to verify the effects of water management method differences in order to reduce CH4 emission from rice paddy at 9 experimental sites in 8 prefectures. In this, we used new gas analyzer which can measure CH4, CO2 and N2O at once developed by National Institute for Agro-Environmental Sciences (NIAES), Japan. In this report, we show the preliminary results in first year of this study. Nakaboshi (mid-season-drainage) is one of cultivation methods in rice paddy that surface water in paddy field is once drained for about 10 days and the field is maintained like upland field to give adequate stress to rice plant for better harvest qualities and yields. Our targeted evaluation was dependencies of Nakaboshi periods lengths and Nakaboshi periods to CH4 emission reduction amounts for total cultivation periods within harvest yield maintained. The longer length of Nakaboshi period was prolonged, the lesser emission amounts of CH4 decreased even after when Nakaboshi period lasted, as a whole. In some soil types, for example in Kagoshima

  16. Infrared-temperature variability in a large agricultural field

    NASA Technical Reports Server (NTRS)

    Millard, J. P.; Goettelman, R. C.; Leroy, M. J.

    1981-01-01

    Dunnigan Agro-Meteorological Experiment airborne thermal scanner images of a large varying-terrain barley field are acquired and analyzed. Temperature variability that may occur within instantaneous fields of view (IFOV) is defined (coefficient of variation: standard deviation/mean temperature in degrees C), and the percentage of the area within various IFOV's within + or - 1, 2, 3, and 5 degrees of the mean is determined. With the exception of very rugged terrain, over 80% of the area within 4, 16, 65 and 258 ha cells was at temperatures within + or - 3 C of the mean cell temperature. Remote measurements of field temperature appeared to be slightly influenced by pixel size in the range 4 ha to 259 ha, and the area percentage within any pixel which contributes within + or - 1, 2, 3, and 5 degrees C of the mean, is nominally the same. In conclusion, no great advantage is found in utilizing a small IFOV instead of a large one for remote sensing of crop temperature.

  17. The Joint Experiment for Crop Assessment and Monitoring (JECAM) Initiative: Developing methods and best practices for global agricultural monitoring

    NASA Astrophysics Data System (ADS)

    Champagne, C.; Jarvis, I.; Defourny, P.; Davidson, A.

    2014-12-01

    Agricultural systems differ significantly throughout the world, making a 'one size fits all' approach to remote sensing and monitoring of agricultural landscapes problematic. The Joint Experiment for Crop Assessment and Monitoring (JECAM) was established in 2009 to bring together the global scientific community to work towards a set of best practices and recommendations for using earth observation data to map, monitor and report on agricultural productivity globally across an array of diverse agricultural systems. These methods form the research and development component of the Group on Earth Observation Global Agricultural Monitoring (GEOGLAM) initiative to harmonize global monitoring efforts and increase market transparency. The JECAM initiative brings together researchers from a large number of globally distributed, well monitored agricultural test sites that cover a range of crop types, cropping systems and climate regimes. Each test site works independently as well as together across multiple sites to test methods, sensors and field data collection techniques to derive key agricultural parameters, including crop type, crop condition, crop yield and soil moisture. The outcome of this project will be a set of best practices that cover the range of remote sensing monitoring and reporting needs, including satellite data acquisition, pre-processing techniques, information retrieval and ground data validation. These outcomes provide the research and development foundation for GEOGLAM and will help to inform the development of the GEOGLAM "system of systems" for global agricultural monitoring. The outcomes of the 2014 JECAM science meeting will be discussed as well as examples of methods being developed by JECAM scientists.

  18. Overview of Field Experience - Degradation Rates & Lifetimes

    SciTech Connect

    Jordan, Dirk; Kurtz, Sarah

    2015-09-14

    The way a PV module fails may depend not only on its design and the materials used in its construction, but also on the weather it experiences, the way it is mounted, and the quality control during its manufacture. This presentation gives an overview of Field Experience - what degradation rates and what lifetimes are being observed in various regions.

  19. Supervised Occupational Experience Record Book for Agricultural Resource Conservation, Environmental Management and Forestry.

    ERIC Educational Resources Information Center

    Nickles, Tom

    The record book was designed to meet the occupational experience recordkeeping requirements of vocational agriculture students enrolled in forestry, environmental management, or agriculture resource conservation programs in Ohio. It provides guidelines and forms for recording on-the-job, in-the-school lab, and occupational experience project data.…

  20. Barriers to Successful Supervised Agricultural Experience Programs in Semi-Rural and Urban High School Agricultural Education Programs.

    ERIC Educational Resources Information Center

    Whaley, David C.; Lucero, Dan

    1993-01-01

    Interviews with educators and students examined the value of and identified barriers to effective use of supervised agricultural experiences (SAE) in a Los Angeles high school and a semirural Colorado high school. Both programs overcame diverse challenges to develop valuable experiential learning through SAEs. Recommendations provide strategies…

  1. Occurrence of an herbicide-resistant plant trait in agricultural field margins.

    PubMed

    Gage, Karla L; Gibson, David J; Young, Bryan G; Young, Julie M; Matthews, Joseph L; Weller, Stephen C; Wilson, Robert G

    2015-09-01

    Agricultural environments allow study of evolutionary change in plants. An example of evolution within agroecological systems is the selection for resistance to the herbicide glyphosate within the weed, Conyza canadensis. Changes in survivorship and reproduction associated with the development of glyphosate resistance (GR) may impact fitness and influence the frequency of occurrence of the GR trait. We hypothesized that site characteristics and history would affect the occurrence of GR C. canadensis in field margins. We surveyed GR occurrence in field margins and asked whether there were correlations between GR occurrence and location, crop rotation, GR crop trait rotation, crop type, use of tillage, and the diversity of herbicides used. In a field experiment, we hypothesized that there would be no difference in fitness between GR and glyphosate-susceptible (GS) plants. We asked whether there were differences in survivorship, phenology, reproduction, and herbivory between 2 GR and 2 GS populations of C. canadensis in agrestal and ruderal habitats. We found that geographic location was an important factor in the occurrence of GR C. canadensis in field margins. Although not consistently associated with either glyphosate resistance or glyphosate susceptibility, there were differences in phenology, survivorship, and herbivory among biotypes of C. canadensis. We found equal or greater fitness in GR biotypes, compared to GS biotypes, and GR plants were present in field margins. Field margins or ruderal habitats may provide refugia for GR C. canadensis, allowing reproduction and further selection to occur as seeds recolonize the agrestal habitat. Agricultural practices may select for ecological changes that feed back into the evolution of plants in ruderal habitats. PMID:26445665

  2. Occurrence of an herbicide-resistant plant trait in agricultural field margins.

    PubMed

    Gage, Karla L; Gibson, David J; Young, Bryan G; Young, Julie M; Matthews, Joseph L; Weller, Stephen C; Wilson, Robert G

    2015-09-01

    Agricultural environments allow study of evolutionary change in plants. An example of evolution within agroecological systems is the selection for resistance to the herbicide glyphosate within the weed, Conyza canadensis. Changes in survivorship and reproduction associated with the development of glyphosate resistance (GR) may impact fitness and influence the frequency of occurrence of the GR trait. We hypothesized that site characteristics and history would affect the occurrence of GR C. canadensis in field margins. We surveyed GR occurrence in field margins and asked whether there were correlations between GR occurrence and location, crop rotation, GR crop trait rotation, crop type, use of tillage, and the diversity of herbicides used. In a field experiment, we hypothesized that there would be no difference in fitness between GR and glyphosate-susceptible (GS) plants. We asked whether there were differences in survivorship, phenology, reproduction, and herbivory between 2 GR and 2 GS populations of C. canadensis in agrestal and ruderal habitats. We found that geographic location was an important factor in the occurrence of GR C. canadensis in field margins. Although not consistently associated with either glyphosate resistance or glyphosate susceptibility, there were differences in phenology, survivorship, and herbivory among biotypes of C. canadensis. We found equal or greater fitness in GR biotypes, compared to GS biotypes, and GR plants were present in field margins. Field margins or ruderal habitats may provide refugia for GR C. canadensis, allowing reproduction and further selection to occur as seeds recolonize the agrestal habitat. Agricultural practices may select for ecological changes that feed back into the evolution of plants in ruderal habitats.

  3. Scaling preferential flow processes in agricultural soils affected by tillage and trafficking at the field scale

    NASA Astrophysics Data System (ADS)

    Filipović, Vilim; Coquet, Yves

    2016-04-01

    There is an accumulation of experimental evidences that agricultural soils, at least the top horizons affected by tillage practices, are not homogeneous and present a structure that is strongly dependent on farming practices like tillage and trafficking. Soil tillage and trafficking can create compacted zones in the soil with hydraulic properties and porosity which are different from those of the non-compacted zones. This spatial variability can strongly influence transport processes and initiate preferential flow. Two or three dimensional models can be used to account for spatial variability created by agricultural practices, but such models need a detailed assessment of spatial heterogeneity which can be rather impractical to provide. This logically raises the question whether and how one dimensional model may be designed and used to account for the within-field spatial variability in soil structure created by agricultural practices. Preferential flow (dual-permeability) modelling performed with HYDRUS-1D will be confronted to classical modelling based on the Richards and convection-dispersion equations using HYDRUS-2D taking into account the various soil heterogeneities created by agricultural practices. Our goal is to derive one set of equivalent 1D soil hydraulic parameters from 2D simulations which accounts for soil heterogeneities created by agricultural operations. A field experiment was carried out in two phases: infiltration and redistribution on a plot by uniform sprinkle irrigation with water or bromide solution. Prior to the field experiment the soil structure of the tilled layer was determined along the face of a large trench perpendicular to the tillage direction (0.7 m depth and 3.1 m wide). Thirty TDR probes and tensiometers were installed in different soil structural zones (Δ compacted soil and Γ macroporous soil) which ensured soil water monitoring throughout the experiment. A map of bromide was constructed from small core samples (4 cm diam

  4. Thermal Infrared Imagery for Better Water Conservation in Agricultural Fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water conservation is an issue that involves all citizens in Georgia. Within the agricultural row crop community, water is a very important part of producing a harvestable and profitable product. Although irrigation is used only as a supplement to natural rainfall, it can greatly affect crop yield...

  5. A field work experience in mental retardation.

    PubMed

    Beardslee, G R

    1976-01-01

    A graduate student specializing in mental retardation found few pertinent electives as well as little opportunity for field work experience. A special arrangement was made for appropriate field work experiences in three types of settings--a large residential institution, school programs, and nursing care facilities. There was little time to view client changes, and rapport with patients and staff was difficult to develop. The advantages included more time with her supervisor, more exposure to organizational and administrative duties, and more exposure to a variety of settings and to the professional roles of numerous therapists. More such field work experiences should be developed to encourage new therapists to choose mental retardation as a specialty. PMID:984162

  6. Agricultural "killing fields": the poisoning of Costa Rican banana workers.

    PubMed

    Sass, R

    2000-01-01

    The poisoning of Costa Rican banana workers by multinational corporations' excessive use of pesticides is not a local issue; it is embedded in a dominant ideology expressed by the phenomenon of globalization. This ideology seeps into every aspect of our social institutions--economic, political, and legal. The practice of this ideological perspective is evident in the industrialization of global agriculture and the shift from "developmentalism"--liberal welfarism, industrialization, and urbanization--to a dominant, undemocratic, global financial elite with "economism" and a neoliberal political agenda overriding the nation-state polis. A specific effect is to transform the agricultural workers of developing countries, such as Costa Rican banana workers, into politically superfluous flesh-and-blood human beings.

  7. Assessing and modelling ecohydrologic processes at the agricultural field scale

    NASA Astrophysics Data System (ADS)

    Basso, Bruno

    2015-04-01

    One of the primary goals of agricultural management is to increase the amount of crop produced per unit of fertilizer and water used. World record corn yields demonstrated that water use efficiency can increase fourfold with improved agronomic management and cultivars able to tolerate high densities. Planting crops with higher plant density can lead to significant yield increases, and increase plant transpiration vs. soil water evaporation. Precision agriculture technologies have been adopted for the last twenty years but seldom have the data collected been converted to information that led farmers to different agronomic management. These methods are intuitively appealing, but yield maps and other spatial layers of data need to be properly analyzed and interpreted to truly become valuable. Current agro-mechanic and geospatial technologies allow us to implement a spatially variable plan for agronomic inputs including seeding rate, cultivars, pesticides, herbicides, fertilizers, and water. Crop models are valuable tools to evaluate the impact of management strategies (e.g., cover crops, tile drains, and genetically-improved cultivars) on yield, soil carbon sequestration, leaching and greenhouse gas emissions. They can help farmers identify adaptation strategies to current and future climate conditions. In this paper I illustrate the key role that precision agriculture technologies (yield mapping technologies, within season soil and crop sensing), crop modeling and weather can play in dealing with the impact of climate variability on soil ecohydrologic processes. Case studies are presented to illustrate this concept.

  8. Implementation of a segmentation method for agricultural fields in aerial sequences of images based on CSAR model

    NASA Astrophysics Data System (ADS)

    Chen, Haijun; Houkes, Zweitze

    1998-09-01

    In this paper, a segmentation method for agricultural fields in aerial sequences of images based on the Circular Symmetri Auto-Regressive (CSAR) model is presented. The image sequences assumed to be acquired by a video camera (RGB-CCD system) from an aeroplane, which moves linearly over the scene. The objects in the scenes being considered in this paper, are agricultural fields. The classes of agricultural fields to be distinguished are determined by the type of crop, e.g. potatoes sugar beet, wheat, etc. In order to recognize and classify these fields from aerial sequence of images, a reliable segmentatio is required. Here texture features are used for segmentation. The implementation of segmentation for agricultural fields in aerial sequences of images is based on CSAR model in texture analysis. By comparing the estimated parameters of CSAR model from different area in an image, the characteristics and the class of a texture may be determined. The paper describes the segmentation method and its evaluation through experiments. Based on segmentation results, classification for surface texture of vegetation from aerial sequences of images is realized.

  9. Passive microwave response to vegetation and soil moisture on agricultural fields

    NASA Astrophysics Data System (ADS)

    Miller, B.; Bullock, Paul R.

    2014-10-01

    The SMAPVEX12 (Soil Moisture Active/Passive Validation Experiment) was carried out over the summer of 2012 in Manitoba, Canada. The goal of the project was to improve the accuracy of satellite based remote sensing of soil moisture. Data were gathered during a 42-day field campaign with surface measurements on 55 different agricultural fields in south-western Manitoba. The extended duration of the campaign, contrast in soil textures, and variety of crop types over the study region provided an excellent range of soil moisture and vegetation conditions. The study fields ranged from bare to fully vegetated, with volumetric soil moisture levels spanning almost 50%. Remotely sensed data were collected on 17 days by aircraft at 1.4 Ghz with a microwave radiometer at two different resolutions. Observed brightness temperatures from the radiometer showed a typical inverse relationship to the near simultaneous soil moisture measurements from the field. This study will focus on improving existing models for passive microwave retrieval of soil moisture using a more extensive data set of field-measured soil temperature, soil moisture and vegetation biomass from a wider range of crops than has been available in previous studies. The extensive ground data collected will allow for both a validation of the high-resolution passive soil moisture estimate, as well as an analysis on the effect of scaling to a lower resolution passive measurement.

  10. A contemporary decennial global Landsat sample of changing agricultural field sizes

    NASA Astrophysics Data System (ADS)

    White, Emma; Roy, David

    2014-05-01

    Agriculture has caused significant human induced Land Cover Land Use (LCLU) change, with dramatic cropland expansion in the last century and significant increases in productivity over the past few decades. Satellite data have been used for agricultural applications including cropland distribution mapping, crop condition monitoring, crop production assessment and yield prediction. Satellite based agricultural applications are less reliable when the sensor spatial resolution is small relative to the field size. However, to date, studies of agricultural field size distributions and their change have been limited, even though this information is needed to inform the design of agricultural satellite monitoring systems. Moreover, the size of agricultural fields is a fundamental description of rural landscapes and provides an insight into the drivers of rural LCLU change. In many parts of the world field sizes may have increased. Increasing field sizes cause a subsequent decrease in the number of fields and therefore decreased landscape spatial complexity with impacts on biodiversity, habitat, soil erosion, plant-pollinator interactions, and impacts on the diffusion of herbicides, pesticides, disease pathogens, and pests. The Landsat series of satellites provide the longest record of global land observations, with 30m observations available since 1982. Landsat data are used to examine contemporary field size changes in a period (1980 to 2010) when significant global agricultural changes have occurred. A multi-scale sampling approach is used to locate global hotspots of field size change by examination of a recent global agricultural yield map and literature review. Nine hotspots are selected where significant field size change is apparent and where change has been driven by technological advancements (Argentina and U.S.), abrupt societal changes (Albania and Zimbabwe), government land use and agricultural policy changes (China, Malaysia, Brazil), and/or constrained by

  11. Engaging Sacred Space: Experiments in the Field

    ERIC Educational Resources Information Center

    della Dora, Veronica

    2011-01-01

    This article reflects on the experience of theorizing sacred space through field practice as part of a fieldtrip to Barcelona. In particular, it focuses on the critical analysis of different approaches to sacred space as applied to various sites in the city. The article opens with a brief review of three mainstream approaches to sacred space: the…

  12. Teacher Knowledge Development in Early Field Experiences

    ERIC Educational Resources Information Center

    Ingersoll, Casey; Jenkins, Jayne M.; Lux, Karen

    2014-01-01

    Investigation of physical education preservice teacher knowledge development has been primarily limited to study of a single semester of early field experience (EFE), with findings from these investigations driving EFE design. The purpose of this research was to investigate what types of knowledge develop and how knowledge evolves and interacts to…

  13. Laboratory and Field Experiments in Motor Learning.

    ERIC Educational Resources Information Center

    Singer, Robert N.; And Others

    This manual for research in motor learning was written for scientifically based physical educators, experimental psychologists, and others interested in the investigation of learning and performance phenomena associated with skill acquisition. Laboratory and field experiments are presented that can be run with or without the presence of a formal…

  14. A contemporary decennial examination of changing agricultural field sizes using Landsat time series data

    PubMed Central

    White, Emma V.

    2015-01-01

    Field size distributions and their changes have not been studied over large areas as field size change datasets are not available. This study quantifies agricultural field size changes in a consistent manner using Landsat satellite data that also provide geographic context for the observed decadal scale changes. Growing season cloud‐free Landsat 30 m resolution images acquired from 9 to 25 years apart were used to extract field object classifications at seven sites located by examination of a global agricultural yield map, agricultural production statistics, literature review, and analysis of the imagery in the US Landsat archive. High spatial resolution data were used to illustrate issues identifying small fields that are not reliably discernible at 30 m Landsat resolution. The predominant driver of field size change was attributed by literature review. Significant field size changes were driven by different factors, including technological advancements (Argentina and USA), government land use and agricultural policies (Malaysia, Brazil, France), and political changes (Albania and Zimbabwe). While observed local field size changes were complex, the reported results suggest that median field sizes are increasing due to technological advancements and changes to government policy, but may decrease where abrupt political changes affect the agricultural sector and where pastures are converted to arable land uses. In the limited sample considered, median field sizes increased from 45% (France) to 159% (Argentina) and decreased from 47% (Brazil) to 86% (Albania). These changes imply significant impacts on landscape spatial configuration and land use diversity with ecological and biogeochemical consequences. PMID:27669424

  15. A contemporary decennial examination of changing agricultural field sizes using Landsat time series data

    PubMed Central

    White, Emma V.

    2015-01-01

    Field size distributions and their changes have not been studied over large areas as field size change datasets are not available. This study quantifies agricultural field size changes in a consistent manner using Landsat satellite data that also provide geographic context for the observed decadal scale changes. Growing season cloud‐free Landsat 30 m resolution images acquired from 9 to 25 years apart were used to extract field object classifications at seven sites located by examination of a global agricultural yield map, agricultural production statistics, literature review, and analysis of the imagery in the US Landsat archive. High spatial resolution data were used to illustrate issues identifying small fields that are not reliably discernible at 30 m Landsat resolution. The predominant driver of field size change was attributed by literature review. Significant field size changes were driven by different factors, including technological advancements (Argentina and USA), government land use and agricultural policies (Malaysia, Brazil, France), and political changes (Albania and Zimbabwe). While observed local field size changes were complex, the reported results suggest that median field sizes are increasing due to technological advancements and changes to government policy, but may decrease where abrupt political changes affect the agricultural sector and where pastures are converted to arable land uses. In the limited sample considered, median field sizes increased from 45% (France) to 159% (Argentina) and decreased from 47% (Brazil) to 86% (Albania). These changes imply significant impacts on landscape spatial configuration and land use diversity with ecological and biogeochemical consequences.

  16. Effect of Leadership Experience on Agricultural Education Student Teacher Self-Efficacy in Classroom Management

    ERIC Educational Resources Information Center

    Wolf, Kattlyn J.; Foster, Daniel D.; Birkenholz, Robert J.

    2009-01-01

    Beginning agriculture teachers often cite classroom management as the most important problem they face in their careers. The purpose of this study was to assess the effect of leadership experience on self-perceived teacher efficacy among agricultural education student teachers. The three dimensions of teacher efficacy addressed in this study…

  17. Supervised Occupational Experience Record Book for Agricultural Resources Conservation, Environmental Management and Forestry: Teacher's Guide.

    ERIC Educational Resources Information Center

    Nickles, Tom

    The guide is designed to aid the instructor in implementing the student guide entitled "Supervised Occupational Experience Record Book For Agricultural Resource Conservation, Environmental Management and Forestry". Intended for use in the secondary level vocational agriculture curriculum, general concepts, student record-keeping skills, and…

  18. Health Experiences, Concerns, and Interactions with Effectiveness of Secondary Agriculture Teachers in the United States.

    ERIC Educational Resources Information Center

    Lee, Jasper S.; Westrom, Lyle E.

    This publication summarizes the findings of several initiatives in studying the health aspects of secondary agriculture teachers in the United States. The study was specifically conducted to determine the health experiences of secondary agriculture teachers, the health problems that cause them to miss work, their health care concerns, personal…

  19. An Experiment in Teaching Agricultural Occupations Information to High School Students.

    ERIC Educational Resources Information Center

    Shontz, David Frank

    To compare the educational effectiveness of three methods of teaching agricultural occupations information associated with land use and conservation to Grade 9 and 10 students of vocational agriculture, 424 students in 24 schools in western and central Pennsylvania were selected for an 18-hour instructional experiment. Eight schools were randomly…

  20. An Assessment of Students' Perceptions toward Factors Influencing Supervised Agricultural Experience Participation

    ERIC Educational Resources Information Center

    Lewis, Lauren J.; Rayfield, John; Moore, Lori L.

    2012-01-01

    The purpose of this study was to investigate student perceptions toward factors influencing Supervised Agricultural Experience (SAE) participation. This descriptive study was conducted in 120 randomly selected agricultural education programs throughout four purposively selected states representative of the National FFA regions. Within each state…

  1. Analysis of the Continuing Decline in Use of Supervised Agricultural Experience (SAE) in New York State.

    ERIC Educational Resources Information Center

    Steele, Roger

    1997-01-01

    When responses from 135 of 222 New York secondary agriculture teachers were compared with a 1983 study, a 10% decrease in supervised agricultural experience (SAE) was found. Barriers were low level of summer employment, limited release time, less funding for transportation, and scheduling problems. A comprehensive overhaul of the concept and…

  2. Pretreatment of agriculture field water for improving membrane flux during pesticide removal

    NASA Astrophysics Data System (ADS)

    Mehta, Romil; Saha, N. K.; Bhattacharya, A.

    2016-09-01

    Pretreatment of feed water to improve membrane flux during filtration of agriculture field water containing substituted phenyl urea pesticide diuron has been reported. Laboratory-made reverse osmosis membrane was used for filtration. Preliminary experiments were conducted with model solution containing natural organic matter extracted from commercial humic acids, divalent ions Ca2+, Mg2+. Membrane fouling was characterized by pure water flux decline, change in membrane hydrophilicity and infrared spectroscopy. Natural organic matter present in field water causes severe membrane fouling. The presence of divalent cations further aggravated fouling. Use of ethylenediaminetetraacetic acid (EDTA) and polyacrylic acids (PAA) in feed resulted in the decrease in membrane fouling. Pretreatment of field water is a must if it is contaminated with micro-organism having membrane fouling potential. Feed water pretreatment and use of PAA restricted membrane fouling to 16 % after 60 h of filtration. Membrane permeate flux decline was maximum at the first 12 h and thereafter remained steady at around 45-46 lm-2h-1 till the end of 60 h. Diuron rejection remained consistently greater than 93 % throughout the experiment. Diuron rejection was found to be unaffected by membrane fouling.

  3. Entry-Level Technical Skills that Agricultural Industry Experts Expected Students to Learn through Their Supervised Agricultural Experiences: A Modified Delphi Study

    ERIC Educational Resources Information Center

    Ramsey, Jon W.; Edwards, M. Craig

    2011-01-01

    The National Research Council's (NRC) Report (1988), Understanding Agriculture: New Directions for Education, called on secondary agricultural education to shift its scope and purpose, including students' supervised agricultural experiences (SAEs). The NRC asserted that this shift should create opportunities for students to acquire supervised…

  4. Perceptions of North Carolina High School Agricultural Educators regarding Students with Special Needs Participating in Supervised Agricultural Experience and FFA Activities

    ERIC Educational Resources Information Center

    Johnson, Lendy; Wilson, Elizabeth; Flowers, Jim; Croom, Barry

    2012-01-01

    The purpose of this study was to examine the perceptions of North Carolina high school agricultural educators toward including students with special needs when implementing Supervised Agricultural Experience and participating in FFA activities. The population was all high school agricultural educators in North Carolina with 12 month employment (N…

  5. Relationship of Length of Vocational Agriculture Teacher Contract to Supervised Occupational Experience Program Scope.

    ERIC Educational Resources Information Center

    Arrington, Larry R.; McCracken, J. David

    1983-01-01

    The primary purpose of the study was to ascertain if the extent to which vocational agriculture teachers are employed on a 12-month basis is related to the scope of supervised occupational experience programs conducted by students. (SSH)

  6. Theme: The Role of the Teacher in Conducting Supervised Agricultural Experience Programs.

    ERIC Educational Resources Information Center

    Agricultural Education Magazine, 2003

    2003-01-01

    Contains 13 theme articles on the role of teachers in supervised agricultural experience (SAE) programs that offer suggestions, ideas, and practices to advance the implementation of SAE programs. (JOW)

  7. Effects of topography and soil properties on recharge at two sites in an agricultural field

    USGS Publications Warehouse

    Delin, G.N.; Healy, R.W.; Landon, M.K.; Böhlke, J.K.

    2000-01-01

    Field experiments were conducted from 1992 to 1995 to estimate ground water recharge rates at two sites located within a 2.7-hectare agricultural field. The field lies in a sand plain setting in central Minnesota and is cropped continuously in field corn. The sites are located at a topographically high (upland) site and a topographically low (lowland) site in an effort to quantify the effects of depression focusing of recharge. Three site-specific methods were used to estimate recharge rates: well hydrograph analysis, chlorofluorocarbon age dating, and an unsaturated zone water balance. All three recharge methods indicated that recharge rates at the lowland site (annual average of all methods of 29 cm) exceeded those at the upland site (annual average of 18 cm). On an annual basis, estimates by the individual methods ranged from 12 to 44 percent of precipitation at the upland site and from 21 to 83 percent at the lowland site. The difference in recharge rates between the sites is primarily attributed to depression focusing of surface water runon at the lowland site. However, two other factors were also important: the presence of thin lamellae at the upland site, and coarser textured soils below a depth of 1.5 m at the lowland site.

  8. Mapping Agricultural Fields in Sub-Saharan Africa with a Computer Vision Approach

    NASA Astrophysics Data System (ADS)

    Debats, S. R.; Luo, D.; Estes, L. D.; Fuchs, T.; Caylor, K. K.

    2014-12-01

    Sub-Saharan Africa is an important focus for food security research, because it is experiencing unprecedented population growth, agricultural activities are largely dominated by smallholder production, and the region is already home to 25% of the world's undernourished. One of the greatest challenges to monitoring and improving food security in this region is obtaining an accurate accounting of the spatial distribution of agriculture. Households are the primary units of agricultural production in smallholder communities and typically rely on small fields of less than 2 hectares. Field sizes are directly related to household crop productivity, management choices, and adoption of new technologies. As population and agriculture expand, it becomes increasingly important to understand both the distribution of field sizes as well as how agricultural communities are spatially embedded in the landscape. In addition, household surveys, a common tool for tracking agricultural productivity in Sub-Saharan Africa, would greatly benefit from spatially explicit accounting of fields. Current gridded land cover data sets do not provide information on individual agricultural fields or the distribution of field sizes. Therefore, we employ cutting edge approaches from the field of computer vision to map fields across Sub-Saharan Africa, including semantic segmentation, discriminative classifiers, and automatic feature selection. Our approach aims to not only improve the binary classification accuracy of cropland, but also to isolate distinct fields, thereby capturing crucial information on size and geometry. Our research focuses on the development of descriptive features across scales to increase the accuracy and geographic range of our computer vision algorithm. Relevant data sets include high-resolution remote sensing imagery and Landsat (30-m) multi-spectral imagery. Training data for field boundaries is derived from hand-digitized data sets as well as crowdsourcing.

  9. Resolving the agriculture-petroleum conflict: the experience of cacao smallholders in Mexico

    SciTech Connect

    Scherr, S.J.

    1983-01-01

    In 1972, PEMEX, the Mexican national oil company, discovered huge reserves of oil and natural gas along the Gulf Coast, and began intensive exploitation in Tabasco and northern Chiapas states. Severe conflict between PEMEX and the agricultural economy of Tabasco seemed certain. But despite problems of labor scarcity, inflation, migration, pollution, agricultural production 1974 to 1979 increased for the state's major products - cacao, coconut, beef, and bananas. This study analyzes how agriculture-petroleum conflicts have been resolved in Tabasco, and how relevant its experience is to other agricultural areas undergoing rapid large-scale industrial development. Cacao farming was chosen as a case study. Detailed farm budget, family employment, and technical production data were used to document farm production strategies. Research results suggest that resolution of agriculture-petroleum conflicts depends on: demographic conditions, employment conditions, agricultural prices, petroleum company flexibility, government development policy, and farmer political strength. Support for the campesino sector is critical.

  10. Developing a Model for Supervised Agricultural Experience Program Quality: A Synthesis of Research.

    ERIC Educational Resources Information Center

    Dyer, James E.; Osborne, Edward W.

    1996-01-01

    A literature review revealed the following: (1) there are no standard criteria to measure the quality of supervised agricultural experience (SAE) programs; (2) teacher attitudes and past SAE experiences strongly influence quality; (3) the number of teachers with SAE experience is declining; and (4) school laboratory facilities are essential for…

  11. Field Evaluation of Preferential Flow in Agricultural Soil of the Mississippi Delta

    NASA Astrophysics Data System (ADS)

    Perkins, K. S.; Nimmo, J. R.; Rose, C. E.; Coupe, R.

    2009-12-01

    In the Bogue Phalia basin in the Delta region of northwestern Mississippi, as in many farmed areas, intensive use of agricultural chemicals raises water quality concerns. The soils are fine textured and often exhibit surface ponding and runoff after irrigation and rainfall. There is extensive surface cracking during extended dry periods. Fields are typically land-formed to promote surface flow into irrigation ditches and streams that feed into larger river ecosystems. Deep percolation below the root zone has been considered to be minimal in this area; however, unsaturated zone processes, including the effects of a declining water table, are not well understood, and there are few measured unsaturated zone data relevant to deep percolation. In this study we assessed solute transport mechanisms within and below the root zone of a fallow soybean field by performing a 2-m ring infiltration experiment. Ponding continued for 67 hours using bromide and rhodamine tracers and subsurface instruments for measuring soil-water content, matric pressure, and solution sampling. Water percolated rapidly below the pond reaching 1 m depth in as little as 30 minutes, indicating preferential flow through the root zone, possibly related to shrink/swell features. Extensive lateral flow of water at shallow depths was apparent as the surface wetted outward to several meters from the pond in all directions with some evidence of preferentiality along slope toward the drainage ditch. Deeper lateral flow was detected at solution samplers 3 m from the pond edge at 5 m depth within a few weeks. Tracer was not detected in the unsaturated zone below 5 m however; the tracer was detected at the water table 12 m below land surface within 10 weeks of the experiment with concentrations increasing over a period of 10 months. A tracer mass balance also suggests the possibility for deep preferential transport of agricultural chemicals within the Bogue Phalia basin.

  12. The Geologic Remote Sensing Field Experiment (GRSFE)

    NASA Technical Reports Server (NTRS)

    Dale-Bannister, Mary A.; Arvidson, Raymond E.; Guinness, Edward E.; Slavney, Susan H.; Stein, Thomas C.

    1991-01-01

    Field measurements for the Geologic Remote Sensing Field Experiment (GRSFE) were concentrated in the Lunar Lake area of Nevada. The GRSFE data are meant to be used in a variety of investigations, including tests of multispectral radiative transfer models for scattering and emission from planetary surfaces in support of the Earth Observing System (EOS), Mars Observer, and Magellan Missions. Studies will also be pursued to establish the neotectonic and paleoclimatic history of the arid southwestern United States. The data will also be used to support Mars Rover Sample Return (MRSR) simulation studies.

  13. Modeling of Movement of Field Gudgeon, Gnathopogon elongatus elongatus, in Agricultural Canals in Yatsu Paddy Fields

    NASA Astrophysics Data System (ADS)

    Takemura, Takeshi; Koizumi, Noriyuki; Mizutani, Masakazu; Mori, Atsushi; Watabe, Keiji

    It is important as quantitative information for making a decision of project sites for networking of water area, to predict reproductive process of fish population when consolidating fish-ways on points dividing fish habitat. To that end, it is necessary to predict the number of individuals migrating to new habitats. Hence, modeling of movement of individuals is necessary as a first step in population modeling. We constructed a mathematical model of movement of field gudgeon in agricultural canals, comparing with observed data obtained by our surveys. A unit time span of this model is 50 days. This model is able to consider existence of 2 types of movement, namely, individuals of sedentary type and individuals of ambulant type. Parameters of the model were decided based on observed data which correspond to 1 unit span. Next, moving distances of 6 individuals for 4 unit span were calculated using those parameters. A histogram of calculated values was similar to that of observed data which correspond to 4 unit span. The model is expected to provide an important immigration component to a population dynamics model which is currently under development. The population model is needed to predict population recovery processes where areas of paddy fields are joined in larger networks through construction of fish-ways.

  14. Topographic effects on denitrification in drained agricultural fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Denitrification is affected by soil moisture, while soil moisture can be affected by topography. Therefore, denitrification can be spatially correlated to topographic gradients. Three prior converted fields on the Delmarva Peninsula were sampled spatially for denitrification enzyme activity. The up...

  15. Successional trends in Sonoran Desert abandoned agricultural fields in northern Mexico

    USGS Publications Warehouse

    Castellanos, A.E.; Martinez, M.J.; Llano, J.M.; Halvorson, W.L.; Espiricueta, M.; Espejel, I.

    2005-01-01

    Excessive ground-water use and saline intrusion to the aquifer led, in less than three decades, to an increase in abandoned agricultural fields at La Costa de Hermosillo, within the Sonoran Desert. Using a chronosequence from years since abandonment, patterns of field succession were developed. Contrary to most desert literature, species replacement was found, both in fields with and without saline intrusion. Seasonal photosynthetic capacity as well as water and nitrogen use efficiencies were different in dominant early and late successional plant species. These ecological findings provided a framework for a general explanation of species dominance and replacement within abandoned agricultural fields in the Sonoran Desert. ?? 2004 Elsevier Ltd. All rights reserved.

  16. Utilizing Urban Environments for Effective Field Experiences

    NASA Astrophysics Data System (ADS)

    MacAvoy, S. E.; Knee, K.

    2014-12-01

    Research surveys suggest that students are demanding more applied field experiences from their undergraduate environmental science programs. For geoscience educators at liberal arts colleges without field camps, university vehicles, or even geology departments, getting students into the field is especially rewarding - and especially challenging. Here, we present strategies that we have used in courses ranging from introductory environmental science for non-majors, to upper level environmental methods and geology classes. Urban locations provide an opportunity for a different type of local "field-work" than would otherwise be available. In the upper-level undergraduate Environmental Methods class, we relied on a National Park area located a 10-minute walk from campus for most field exercises. Activities included soil analysis, measuring stream flow and water quality parameters, dendrochronology, and aquatic microbe metabolism. In the non-majors class, we make use of our urban location to contrast water quality in parks and highly channelized urban streams. Here we share detailed lesson plans and budgets for field activities that can be completed during a class period of 2.5 hours with a $75 course fee, show how these activities help students gain quantitative competency, and provide student feedback about the classes and activities.

  17. Early Field Experiences in Teacher Education. ERIC Digest.

    ERIC Educational Resources Information Center

    Huling, Leslie

    Quality teacher education programs provide candidates with many early field experiences in diverse settings. This Digest examines complexities and challenges of early field experiences, noting the nature and degree of early field experiences within teacher education programs. Through field experiences, teacher candidates observe and work with real…

  18. Across the Arctic Teachers Experience Field Research

    NASA Astrophysics Data System (ADS)

    Warnick, W. K.; Warburton, J.; Wiggins, H. V.; Marshall, S. A.; Darby, D. A.

    2005-12-01

    From studying snow geese on the North Slope of Alaska to sediment coring aboard the U.S. Coast Guard Cutter Healy in the Arctic Ocean, K-12 teachers embark on scientific expeditions as part of a program that strives to make science in the Arctic a "virtual" reality. In the past two years, seventeen K-12 teachers have participated in Teachers and Researchers Exploring and Collaborating (TREC), a program that pairs teachers with researchers to improve science education through arctic field experiences. TREC builds on the scientific and cultural opportunities of the Arctic, linking research and education through topics that naturally engage students and the wider public. TREC includes expeditions as diverse as studying plants at Toolik Field Station, a research facility located 150 miles above the Arctic Circle; climate change studies in Norway's Svalbard archipelago; studying rivers in Siberia; or a trans-arctic expedition aboard the USCGC Healy collecting an integrated geophysical data set. Funded by the National Science Foundation Office of Polar Programs, TREC offers educators experiences in scientific inquiry while encouraging the public and students to become active participants in the scientific inquiry by engaging them virtually in arctic research. TREC uses online outreach elements to convey the research experience to a broad audience. While in remote field locations, teachers and researchers interact with students and the public through online seminars and live calls from the field, online journals with accompanying photos, and online bulletin boards. Since the program's inception in 2004, numerous visitors have posted questions or interacted with teachers, researchers, and students through the TREC website (http://www.arcus.org/trec). TREC teachers are required to transfer their experience of research and current science into their classroom through the development of relevant activities and resources. Teachers and researchers are encouraged to participate

  19. The Impact of Landscape Complexity on Invertebrate Diversity in Edges and Fields in an Agricultural Area.

    PubMed

    Evans, Tracy R; Mahoney, Meredith J; Cashatt, Everett D; Noordijk, Jinze; de Snoo, Geert; Musters, C J M

    2016-01-01

    Invertebrate diversity is important for a multitude of ecosystem services and as a component of the larger ecological food web. A better understanding of the factors influencing invertebrate taxonomic richness and diversity at both local and landscape scales is important for conserving biodiversity within the agricultural landscape. The aim of this study was to determine if invertebrate richness and diversity in agricultural field interiors and edges in central Illinois, USA, were related to the complexity of the surrounding landscape. Our results show taxonomic richness and diversity in field edges is positively related to large scale landscape complexity, but the relationship is negative for field interiors. These unexpected results need further study.

  20. The Impact of Landscape Complexity on Invertebrate Diversity in Edges and Fields in an Agricultural Area

    PubMed Central

    Evans, Tracy R.; Mahoney, Meredith J.; Cashatt, Everett D.; Noordijk, Jinze; de Snoo, Geert; Musters, C. J. M.

    2016-01-01

    Invertebrate diversity is important for a multitude of ecosystem services and as a component of the larger ecological food web. A better understanding of the factors influencing invertebrate taxonomic richness and diversity at both local and landscape scales is important for conserving biodiversity within the agricultural landscape. The aim of this study was to determine if invertebrate richness and diversity in agricultural field interiors and edges in central Illinois, USA, were related to the complexity of the surrounding landscape. Our results show taxonomic richness and diversity in field edges is positively related to large scale landscape complexity, but the relationship is negative for field interiors. These unexpected results need further study. PMID:26848691

  1. Overview of engineering and agricultural design considerations of the Raft River soil-warming and heat-dissipation experiment

    SciTech Connect

    Stanley, N.E.; Engen, I.A.; Yrene, C.S.

    1982-04-01

    The engineering and agricultural considerations of the Raft River soil-warming and heat-dissipation experiment are presented. The experiment is designed to investigate the thermal characteristics of a subsurface pipe network for cooling power-plant condenser effluent, and crop responses to soil warming in an open-field plot. The subsurface soil-warming system is designed to dissipate approximately 100 kW of heat from circulating, 38/sup 0/C geothermal water. Summer operating conditions in the Raft River area, located on the Intermountain Plateau are emphasized. Design is based on the thermal characteristics of the local soil, the climate of the Raft River Valley, management practices for normal agriculture, and the need for an unheated control plot. The resultant design calls for 38-mm polyvinyl chloride (PVC) pipe in a grid composed of parallel loops, for dissipating heat into a 0.8-hectare experimental plot.

  2. A Machine Learning Approach to Mapping Agricultural Fields Across Sub-Saharan Africa

    NASA Astrophysics Data System (ADS)

    Debats, S. R.; Fuchs, T. J.; Thompson, D. R.; Estes, L. D.; Evans, T. P.; Caylor, K. K.

    2013-12-01

    Food production in sub-Saharan Africa is dominated by smallholder agriculture. Rainfed farming practices and the prevailing dryland conditions render crop yields vulnerable to increasing climatic variability. As a result, smallholder farmers are among the poorest and most food insecure groups among the region's population. Quantifying the distribution of smallholder agriculture across sub-Saharan Africa would greatly assist efforts to boost food security. Existing agricultural land cover data sets are limited to estimating the percentage of cropland within a coarse grid cell. The goal of this research is to develop a statistical machine learning algorithm to map individual agricultural fields, mirroring the accuracy of hand-digitization. For the algorithm, a random forest pixel-wise classifier learns by example from training data to distinguish between fields and non-fields. The algorithm then applies this training to classify previously unseen data. These classifications can then be smoothed into coherent regions corresponding to agricultural fields. Our training data set consists of hand-digitized boundaries of agricultural fields in South Africa, commissioned by its government in 2008. Working with 1 km x 1 km scenes across South Africa, the hand-digitized field boundaries are matched with satellite images extracted from Google Maps. To highlight different information contained within the images, several image processing filters are applied. The inclusion of Landsat images for additional training information is also explored. After training and testing the algorithm in South Africa, we aim to expand our mapping efforts across sub-Saharan Africa. Through Princeton's Mapping Africa project, crowdsourcing will produce additional training data sets of hand-digitized field boundaries in new areas of interest. This algorithm and the resulting data sets will provide previously unavailable information at an unprecedented level of detail on the largest and most

  3. Magnetic Field Experiment Data Analysis System

    NASA Technical Reports Server (NTRS)

    Holland, D. B.; Zanetti, L. J.; Suther, L. L.; Potemra, T. A.; Anderson, B. J.

    1995-01-01

    The Johns Hopkins University Applied Physics Laboratory (JHU/APL) Magnetic Field Experiment Data Analysis System (MFEDAS) has been developed to process and analyze satellite magnetic field experiment data from the TRIAD, MAGSAT, AMPTE/CCE, Viking, Polar BEAR, DMSP, HILAT, UARS, and Freja satellites. The MFEDAS provides extensive data management and analysis capabilities. The system is based on standard data structures and a standard user interface. The MFEDAS has two major elements: (1) a set of satellite unique telemetry processing programs for uniform and rapid conversion of the raw data to a standard format and (2) the program Magplot which has file handling, data analysis, and data display sections. This system is an example of software reuse, allowing new data sets and software extensions to be added in a cost effective and timely manner. Future additions to the system will include the addition of standard format file import routines, modification of the display routines to use a commercial graphics package based on X-Window protocols, and a generic utility for telemetry data access and conversion.

  4. Increased spring flooding of agricultural fields will exhibit altered production of greenhouse gases

    NASA Astrophysics Data System (ADS)

    Paul, R. F.; Smith, C. M.; Smyth, E. M.; Kantola, I. B.; DeLucia, E. H.

    2013-12-01

    The U.S. Corn Belt currently is a net source of carbon dioxide and nitrous oxide to the atmosphere, but is also a sink of methane. Among the proposed effects of climate change in the North American Midwest region is an increase in the frequency and duration of spring flooding events. This would cause ponding in fields which may change the greenhouse gas balance of the region, especially by providing a suitable anoxic environment for the proliferation of methanogens, increasing methane emissions. To determine whether methanogenesis occurs in flooded agricultural soils of the Midwest and how other gas fluxes are affected, we installed collars into the ground of a research field located in central Illinois. The control group was maintained at the same conditions as the surrounding field. Two groups of collars were sustained with water flooding the headspaces via a drip irrigation system; one treatment was analyzed for gas fluxes of CH4, N2O, and CO2 evolving from the collars, and a separate treatment of flooded collars was used for soil sampling. Comparing flooded soils versus control we measured reduced N2O fluxes (-3.12 x 10-6 × 6.8 x 10-7 g N m-2 min-1), reduced CO2 fluxes (-6.13 x 10-3 × 9.3 x 10-4 g CO2 m-2 min-1), and increased methane fluxes (+2.72 x 10-6 × 5.8 x 10-7 g CH4 m-2 min-1). After only one week of treatment the flooded soils switched from being sinks to sources of methane, which continued across the duration of the experiment. These preliminary results indicate that methanogenesis occurs in flooded agricultural fields, and suggest including regional modeling into further study. Although the global warming potential of methane is 25 times greater than CO2, our measured rates of methane production were compensated by reductions in nitrous oxide and CO2 fluxes, reducing the total 100-year horizon global warming potential of the flooded soils we studied by 64.8%. This indicates that accounting for more frequent seasonal ponding would significantly

  5. Field-based study of connectivity in an agricultural catchment

    NASA Astrophysics Data System (ADS)

    Lexartza-Artza, I.; Wainwright, J.

    2009-12-01

    Field-based studies of hydrological connectivity can provide context-specific knowledge that might both help understand dynamic complex systems and contribute to other synthetic or modelling approaches. The importance of such an understanding of catchment processes and also of the knowledge of catchment connections with water bodies and the changes of concentration with scale for Integrated Catchment Management has been increasingly emphasized. To provide a holistic understanding, approaches to the study of connectivity need to include both structural and functional aspects of the system and must consider the processes taking place within and across different temporal and spatial scales. A semi-quantitative nested approach has been used to investigate connectivity and study the interactions and feedbacks between the factors influencing transfer processes in the Ingbirchworth Catchment, in the uplands of the River Don, England. A series of reconnaissance techniques have been combined with monitoring of aspects such as rainfall, runoff, sediment transfer and soil-moisture distribution from plot to catchment scale and with consideration of linkages between land and water bodies. The temporal aspect has also been considered, with a special focus on the temporal distribution of events and the influence of longer term catchment changes such as those in land use and management practices. A variability of responses has been observed in relation to the characteristics of events, land use and scale of observation, with elements traditionally considered as limiting or enhancing connectivity responding differently under changing conditions. Sediment redistribution, reshaping of structure and consequent reinforcing loops can be observed across all land uses and landscape units, but the relevance it terms of effective connectivity of highly connected patches varies as the scale is increased. The knowledge acquired can contribute to recognise emerging processes significant for

  6. Technology-Focused Early Field Experiences in Preservice Teacher Education

    ERIC Educational Resources Information Center

    Lux, Nicholas J.

    2013-01-01

    Although a broad body of research exists on field experiences in teacher education, one specific area of inquiry lacking substantial current research is that of technology-focused early field experiences, or field experiences that occur prior to student teaching and more formal clinical experiences. To address this gap, I conducted this…

  7. Challenges and Opportunities for Developing Capacity in Earth Observations for Agricultural Monitoring: The GEOGLAM Experience

    NASA Astrophysics Data System (ADS)

    Whitcraft, A. K.; Di Bella, C. M.; Becker Reshef, I.; Deshayes, M.; Justice, C. O.

    2015-12-01

    Since 2011, the Group on Earth Observations Global Agricultural Monitoring (GEOGLAM) Initiative has been working to strengthen the international community's capacity to use Earth observation (EO) data to derive timely, accurate, and transparent information on agriculture, with the goals of reducing market volatility and promoting food security. GEOGLAM aims to develop capacity for EO-based agricultural monitoring at multiple scales, from national to regional to global. This is accomplished through training workshops, developing and transferring of best-practices, establishing networks of broad and sustainable institutional support, and designing or adapting tools and methodologies to fit localized contexts. Over the past four years, capacity development activities in the context of GEOGLAM have spanned all agriculture-containing continents, with much more work to be done, particularly in the domains of promoting access to large, computationally-costly datasets. This talk will detail GEOGLAM's experiences, challenges, and opportunities surrounding building international collaboration, ensuring institutional buy-in, and developing sustainable programs.

  8. FIFE, First ISLSCP Field Experiment - Results overview

    NASA Technical Reports Server (NTRS)

    Hall, F. G.; Markham, B. J.; Wang, J. R.; Huemmerich, F.; Sellers, P. J.; Strebel, D. E.; Kanemasu, E. T.; Kelly, Robert D.; Blad, Blaine L.

    1990-01-01

    Results of the analyses of the First International Satellite Land-Surface Climatology Project Field Experiment (FIFE) are described which relate to the mass and energy flux of a particular area. The extensive satellite and ground data are used to analyze the energy balance over the FIFE site, monitor the energy-budget components, study atmospheric effects on remote sensing, examine cloud cover, and investigate fluxes in the atmospheric boundary layer. The results verify existing theories relating energy-balance components with surface biology and remote sensing, and satellites can be used to estimate surface-energy budgets. Some analyses provide data that contradict present theories regarding thermodynamic and biophysical methodologies for estimating surface-heat fluxes.

  9. [Runoff Pollution Experiments of Paddy Fields Under Different Irrigation Patterns].

    PubMed

    Zhou, Jing-wen; Su, Bao-lin; Huang, Ning-bo; Guan, Yu-tang; Zhao, Kun

    2016-03-15

    To study runoff and non-point source pollution of paddy fields and to provide a scientific basis for agricultural water management of paddy fields, paddy plots in the Jintan City and the Liyang City were chosen for experiments on non-point source pollution, and flood irrigation and intermittent irrigation patterns were adopted in this research. The surface water level and rainfall were observed during the growing season of paddies, and the runoff amount from paddy plots and loads of total nitrogen (TN) and total phosphorus (TP) were calculated by different methods. The results showed that only five rain events of totally 27 rainfalls and one artificially drainage formed non-point source pollution from flood irrigated paddy plot, which resulted in a TN export coefficient of 49.4 kg · hm⁻² and a TP export coefficient of 1.0 kg · hm⁻². No any runoff event occurred from the paddy plot with intermittent irrigation even in the case of maximum rainfall of 95.1 mm. Runoff from paddy fields was affected by water demands of paddies and irrigation or drainage management, which was directly correlated to surface water level, rainfall amount and the lowest ridge height of outlets. Compared with the flood irrigation, intermittent irrigation could significantly reduce non-point source pollution caused by rainfall or artificial drainage. PMID:27337888

  10. Bird use of agricultural fields under reduced and conventional tillage in the Texas Panhandle

    USGS Publications Warehouse

    Flickinger, Edward L.; Pendleton, G.W.

    1994-01-01

    We conducted bird surveys in reduced-tillage and conventional tillage fields in spring, summer, fall, and winter from 1987 to 1991 in the Texas Panhandle. Eastern meadowlarks, longspurs, and savannah sparrows were more common in reduced-tillage (sorghum and wheat stubble) fields than in conventionally tilled (plowed) fields in at least 1 season. Other species also had patterns suggestive of greater abundance in reduced-tillage fields. Hornedlarks, which prefer habitat with sparse vegetation, were more abundant in plowed fields in all seasons except summer. Bird diversity was greater in reduced-tillage fields than in conventionally tilled fields in summer. Cover density and height were greater in reduced tillage fields in all seasons except spring. Cover density and height rather than cover composition (e.g.,grain stubble or live plants) seemed to be the important factors affecting bird distribution. Patterns of bird abundance between sorghum and wheat stubble fields also were dependent on cover. Herbicide use was not greater in reduced-tillage fields than in conventionally tilled fields. Reduced-tillage agriculture for sorghum and wheat farming should be encouraged in the southern Great Plains as a means of improving the attractiveness of agricultural land to many bird species.

  11. Long-Term Network Experiments and Interdisciplinary Campaigns Conducted by the USDA-Agricultural Research Service

    NASA Astrophysics Data System (ADS)

    Goodrich, D. C.; Kustas, W. P.; Cosh, M. H.; Moran, S. M.; Marks, D. G.; Jackson, T. J.; Bosch, D. D.; Rango, A.; Seyfried, M. S.; Scott, R. L.; Prueger, J. H.; Starks, P. J.; Walbridge, M. R.

    2014-12-01

    The USDA-Agricultural Research Service has led, or been integrally involved in, a myriad of interdisciplinary field campaigns in a wide range of locations both nationally and internationally. Many of the shorter campaigns were anchored over the existing national network of ARS Experimental Watersheds and Rangelands. These long-term outdoor laboratories provided a critical knowledge base for designing the campaigns as well as historical data, hydrologic and meteorological infrastructure coupled with shop, laboratory, and visiting scientist facilities. This strong outdoor laboratory base enabled cost-efficient campaigns informed by historical context, local knowledge, and detailed existing watershed characterization. These long-term experimental facilities have also enabled much longer term lower intensity experiments, observing and building an understanding of both seasonal and inter-annual biosphere-hydrosphere-atmosphere interactions across a wide range of conditions. A sampling of these experiments include MONSOON'90, SGP97, SGP99, Washita'92, Washita'94, SMEX02-05 and JORNEX series of experiments, SALSA, CLASIC and longer-term efforts over the ARS Little Washita, Walnut Gulch, Little River, Reynolds Creek, and OPE3 Experimental Watersheds. This presentation will review some of the highlights and key findings of these campaigns and long-term efforts including the inclusion of many of the experimental watersheds and ranges in the Long-Term Agro-ecosystems Research (LTAR) network. The LTAR network also contains several locations that are also part of other observational networks including the CZO, LTER, and NEON networks. Lessons learned will also be provided for scientists initiating their participation in large-scale, multi-site interdisciplinary science.

  12. The fate and transport of the Cry1Ab protein in an agricultural field and laboratory aquatic microcosms.

    PubMed

    Strain, Katherine E; Lydy, Michael J

    2015-08-01

    Genetically engineered crops expressing insecticidal crystalline proteins derived from Bacillus thuringiensis (Bt), were commercialized almost two decades ago as a means to manage agricultural pests. The Bt proteins are highly specific and only lethal upon ingestion, limiting the scope of toxicity to target insects. However, concern of exposure to non-target organisms and negative public perceptions regarding Bt crops has caused controversy surrounding their use. The objective of this research was to monitor the fate and transport of a Bt protein, Cry1Ab, in a large-scale agricultural field containing maize expressing the Cry1Ab protein and a non-Bt near isoline, and in aquatic microcosms. The highest environmental concentrations of the Cry1Ab protein were found in runoff water and sediment, up to 130ngL(-1) and 143ngg(-1) dry weight, respectively, with the Cry1Ab protein detected in both Bt and non-Bt maize fields. As surface runoff and residual crop debris can transport Bt proteins to waterways adjacent to agricultural fields, a series of laboratory experiments were conducted to determine the potential fate of the Cry1Ab protein under different conditions. The results showed that sediment type and temperature can influence the degradation of the Cry1Ab protein in an aquatic system and that the Cry1Ab protein can persist for up to two months. Although Cry1Ab protein concentrations measured in the field soil indicate little exposure to terrestrial organisms, the consistent input of Bt-contaminated runoff and crop debris into agricultural waterways is relevant to understanding potential consequences to aquatic species. PMID:25828252

  13. Comparing erosion rates in burnt forests and agricultural fields for a mountain catchment in NW Iberia

    NASA Astrophysics Data System (ADS)

    Nunes, João Pedro; Marisa Santos, Juliana; Bernard-Jannin, Léonard; Keizer, Jan Jacob

    2013-04-01

    A large part of northwestern Iberia is nowadays covered by commercial forest plantations of eucalypts and maritime pines, which have partly replaced traditional agricultural land-uses. The humid Mediterranean climate, with mild wet winters and warm dry summers, creates favorable conditions for the occurrence of frequent and recurrent forest fires. Erosion rates in recently burnt areas have been the subject of numerous studies; however, there is still a lack of information on their relevance when compared with agricultural erosion rates, impairing a comprehensive assessment of the role of forests for soil protection. This study focuses on Macieira de Alcoba, head-water catchment in the Caramulo Mountain Range, north-central Portugal, with a mixture of agricultural fields (mostly a rotation between winter pastures and summer cereals) on the lower slopes and forest plantations (mostly eucalypts) on the upper slopes. Agricultural erosion in this catchment has been monitored since 2010; a forest fire in 2011 presented an opportunity to compare post-fire and agricultural erosion rates at nearby sites with comparable soil and climatic conditions. Erosion rates were monitored between 2010 and 2013 by repeated surveys of visible erosion features and, in particular, by mapping and measuring rills and gullies after important rainfall events. During the 2011/2012 hydrological year, erosion rates in the burnt forest were two orders of magnitude above those in agricultural fields, amounting to 17.6 and. 0.1 Mg ha-1, respectively. Rills were widespread in the burnt area, while in the agricultural area they were limited to a small number of fields with higher slope; these particular fields experienced an erosion rate of 2.3 Mg ha-1, still one order of magnitude lower than at the burnt forest site. The timing of the erosion features was also quite distinct for the burnt area and the agricultural fields. During the first nine months after the fire, rill formation was not observed in

  14. Magnetic field experiment on the Freja Satellite

    NASA Astrophysics Data System (ADS)

    Freja Magnetic Field Experiment Team

    1994-11-01

    Freja is a Swedish scientific satellite mission to study fine scale auroral processes. Launch was October 6, 1992, piggyback on a Chinese Long March 2C, to the present 600×1750 km, 63° inclination orbit. The JHU/APL provided the Magnetic Field Experiment (MFE), which includes a custom APL-designed Forth, language microprocessor. This approach has led to a truly generic and flexible design with adaptability to differing mission requirements and has resulted in the transfer of significant ground analysis to on-board processing. Special attention has been paid to the analog electronic and digital processing design in an effort to lower system noise levels, verified by inflight data showing unprecedented system noise levels for near-Earth magnetic field measurements, approaching the fluxgate sensor levels. The full dynamic range measurements are of the 3-axis Earth's magnetic field taken at 128 vector samples s-1 and digitized to 16 bit, resolution, primarily used to evaluate currents and the main magnetic field of the Earth. Additional 3-axis ‘AC’ channels are bandpass filtered from 1.5 to 128 Hz to remove the main field spin signal, the range is±650 nT. These vector measurements cover Pc waves to ion gyrofrequency magnetic wave signals up to the oxygen gyrofrequency (˜40 Hz). A separate, seventh channel samples the spin axis sensor with a bandpass filter of 1.5 to 256 Hz, the signal of which is fed to a software FFT. This on-board FFT processing covers the local helium gyrofrequencies (˜160 Hz) and is plotted in the Freja Summary Plots (FSPs) along with disturbance fields. First data were received in the U.S. October 16 from Kiruna, Sweden via the Internet and SPAN e-mail networks, and were from an orbit a few hours earlier over Greenland and Sweden. Data files and data products, e.g., FSPs generated at the Kiruna ground station, are communicated in a similar manner through an automatic mail distribution system in Stockholm to PIs and various users

  15. Simple, Low-Cost Data Collection Methods for Agricultural Field Studies.

    ERIC Educational Resources Information Center

    Koenig, Richard T.; Winger, Marlon; Kitchen, Boyd

    2000-01-01

    Summarizes relatively simple and inexpensive methods for collecting data from agricultural field studies. Describes methods involving on-farm testing, crop yield measurement, quality evaluations, weed control effectiveness, plant nutrient status, and other measures. Contains 29 references illustrating how these methods were used to conduct…

  16. Anthropogenic effects on soil quality in ancient terraced agricultural fields of Chihuahua, Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural soil quality was investigated in ancient field systems near Casas Grandes (also known as Paquimé), one of the largest and most complex prehistoric settlements in the North American Southwest. This research was completed as part of an interdisciplinary study of the anthropogenic ecology...

  17. 140° view of two agricultural fields with traces of irrigation ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    140° view of two agricultural fields with traces of irrigation ditches south of the lower holding pond. This negative forms a 360° composite panoramic when joined with AZ-2-75 and AZ-2-76. See AZ-2-86 for color version. - Tassi Ranch, Tassi Springs, Littlefield, Mohave County, AZ

  18. Definition of zones with different levels of productivity within an agricultural field using fuzzy modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zoning of agricultural fields is an important task for utilization of precision farming technology. One method for the definition of zones with different levels of productivity is based on fuzzy indicator model. Fuzzy indicator model for identification of zones with different levels of productivit...

  19. The Search for Energy Alternatives: Responses Received by State Agricultural Experiment Stations.

    ERIC Educational Resources Information Center

    Cross, William M.

    Directors of the 51 agricultural experiment stations in the United States (including Guam) were mailed questionnaires inquiring as to the extent of requests which had been received for information about wind, solar, and other energy alternatives such as wood and gasahol. There was a total response of 88% with three mailings. The returned…

  20. Guidelines and Procedures: Directed Work-Experience Programs in Vocational Agricultural Education.

    ERIC Educational Resources Information Center

    Cushman, Harold R.; And Others

    The growing demand for increased diversification of programs and greater specialization in work experience for students of vocational agriculture has created a need for sound teacher guidelines for initiating, establishing, and administering a vocational education program that combines the benefits of school instruction, on-the-job training, and…

  1. Status of Job Motivation and Job Performance of Field Level Extension Agents in Ogun State: Implications for Agricultural Development

    ERIC Educational Resources Information Center

    Fabusoro, E.; Awotunde, J. A.; Sodiya, C. I.; Alarima, C. I.

    2008-01-01

    The field level extension agents (FLEAs) are the lifeline of the agricultural extension system in Nigeria. Their motivation and job performance are therefore important to achieving faster agricultural development in Nigeria. The study identified the factors motivating the FLEAs working with Ogun State Agricultural development programme (OGADEP)…

  2. Californian demonstration and validation of automated agricultural field extraction from multi-temporal Landsat data

    NASA Astrophysics Data System (ADS)

    Yan, L.; Roy, D. P.

    2013-12-01

    The spatial distribution of agricultural fields is a fundamental description of rural landscapes and the location and extent of fields is important to establish the area of land utilized for agricultural yield prediction, resource allocation, and for economic planning. To date, field objects have not been extracted from satellite data over large areas because of computational constraints and because consistently processed appropriate resolution data have not been available or affordable. We present a fully automated computational methodology to extract agricultural fields from 30m Web Enabled Landsat data (WELD) time series and results for approximately 250,000 square kilometers (eleven 150 x 150 km WELD tiles) encompassing all the major agricultural areas of California. The extracted fields, including rectangular, circular, and irregularly shaped fields, are evaluated by comparison with manually interpreted Landsat field objects. Validation results are presented in terms of standard confusion matrix accuracy measures and also the degree of field object over-segmentation, under-segmentation, fragmentation and shape distortion. The apparent success of the presented field extraction methodology is due to several factors. First, the use of multi-temporal Landsat data, as opposed to single Landsat acquisitions, that enables crop rotations and inter-annual variability in the state of the vegetation to be accommodated for and provides more opportunities for cloud-free, non-missing and atmospherically uncontaminated surface observations. Second, the adoption of an object based approach, namely the variational region-based geometric active contour method that enables robust segmentation with only a small number of parameters and that requires no training data collection. Third, the use of a watershed algorithm to decompose connected segments belonging to multiple fields into coherent isolated field segments and a geometry based algorithm to detect and associate parts of

  3. Maize production and land degradation: a Portuguese agriculture field case study

    NASA Astrophysics Data System (ADS)

    Ferreira, Carla S. S.; Pato, João V.; Moreira, Pedro M.; Valério, Luís M.; Guilherme, Rosa; Casau, Fernando J.; Santos, Daniela; Keizer, Jacob J.; Ferreira, António J. D.

    2016-04-01

    While food security is a main challenge faced by human kind, intensive agriculture often leads to soil degradation which then can threaten productivity. Maize is one of the most important crops across the world, with 869 million tons produced worldwide in 2012/2013 (IGC 2015), of which 929.5 thousand tons in Portugal (INE 2014). In Portugal, maize is sown in April/May and harvest occurs generally in October. Conventional maize production requires high inputs of water and fertilizers to achieve higher yields. As Portuguese farmers are typically rather old (on average, 63 years) and typically have a low education level (INE 2014), sustainability of their land management practises is often not a principal concern. This could explain why, in 2009, only 4% of the Portuguese temporary crops were under no-tillage, why only 8% of the farmers performed soil analyses in the previous three years, and why many soils have a low organic matter content (INE 2014). Nonetheless, sustainable land management practices are generally accepted to be the key to reducing agricultural soil degradation, preventing water pollution, and assuring long-term crop production objectives and food security. Sustainable land management should therefore not only be a concern for policy makers but also for farmers, since land degradation will have negative repercussions on the productivity, thus, on their economical income. This paper aims to assess the impact of maize production on soil properties. The study focusses on an 8 ha maize field located in central Portugal, with a Mediterranean climate on a gently sloping terrain (<3%) and with a soil classified as Eutric Fluvisol. On the field, several experiments were carried out with different maize varieties as well as with different fertilizers (solid, liquid and both). Centre pivot irrigation was largely used. Data is available from 2003, and concerns crop yield, fertilization and irrigation practices, as well as soil properties assessed through

  4. Nitrate leaching to shallow groundwater systems from agricultural fields with different management practices.

    PubMed

    Nila Rekha, P; Kanwar, R S; Nayak, A K; Hoang, C K; Pederson, C H

    2011-09-01

    Monitoring the concentration of NO(3)-N from agricultural fields to the subsurface and shallow ground water resources have received considerable interest worldwide, since agriculture has been identified as a major source of nitrate-nitrogen (NO(3)-N) pollution of groundwater systems in intensively farmed watersheds. A study was conducted to quantify the impact of two tillage practices viz. chisel plow (CP) and no till (NT) with liquid swine manure application on nitrate leaching to the shallow ground water system under corn-soybean production system. This study is part of the long-term field experiments conducted at Iowa State University using completely randomized block design. The NO(3)-N concentrations in the shallow ground water were monitored at three depths viz., a network of subsurface drains at a depth of 1.2 m and piezometers at depths of 1.8 m and 2.4 m. Results of this study showed that the average NO(3)-N concentration during the study period was 16.1 mg l(-1), 14.4 mg l(-1) and 11.8 mg l(-1) at 1.2 m, 1.8 m and 2.4 m depths, respectively implying significant amount of NO(3)-N leaching past the subsurface drain depth of 1.2 m into the shallow groundwater but the NO(3)-N concentration decreases with the depth. The NO(3)-N concentrations in shallow groundwater were significantly higher under the chisel plow system in comparison with the no till method of tillage. Fall application of liquid swine manure caused more leaching in comparison with the spring application. Higher NO(3)-N concentration was observed under corn in comparison with the soybean plots. An in-depth analysis of the data showed a definite relationship between the NO(3)-N concentration in subsurface drain water at a depth of 1.2 m and shallow groundwater at depths of 1.8 m and 2.4 m depths.

  5. Automated Agricultural Field Extraction from Multi-temporal Web Enabled Landsat Data

    NASA Astrophysics Data System (ADS)

    Yan, L.; Roy, D. P.

    2012-12-01

    Agriculture has caused significant anthropogenic surface change. In many regions agricultural field sizes may be increasing to maximize yields and reduce costs resulting in decreased landscape spatial complexity and increased homogenization of land uses with potential for significant biogeochemical and ecological effects. To date, studies of the incidence, drivers and impacts of changing field sizes have not been undertaken over large areas because of computational constraints and because consistently processed appropriate resolution data have not been available or affordable. The Landsat series of satellites provides near-global coverage, long term, and appropriate spatial resolution (30m) satellite data to document changing field sizes. The recent free availability of all the Landsat data in the U.S. Landsat archive now provides the opportunity to study field size changes in a global and consistent way. Commercial software can be used to extract fields from Landsat data but are inappropriate for large area application because they require considerable human interaction. This paper presents research to develop and validate an automated computational Geographic Object Based Image Analysis methodology to extract agricultural fields and derive field sizes from Web Enabled Landsat Data (WELD) (http://weld.cr.usgs.gov/). WELD weekly products (30m reflectance and brightness temperature) are classified into Satellite Image Automatic Mapper™ (SIAM™) spectral categories and an edge intensity map and a map of the probability of each pixel being agricultural are derived from five years of 52 weeks of WELD and corresponding SIAM™ data. These data are fused to derive candidate agriculture field segments using a variational region-based geometric active contour model. Geometry-based algorithms are used to decompose connected segments belonging to multiple fields into coherent isolated field objects with a divide and conquer strategy to detect and merge partial circle

  6. Experiments with Low Voltage Field Emission EPMA

    NASA Astrophysics Data System (ADS)

    Fournelle, J.; Cathey, H. E.

    2014-12-01

    We report results from 5-7 keV Field Emission EPMA experiments on selected natural minerals and synthetic materials to illustrate some strengths -- and pitfalls --of low keV FE-EPMA. In a silicate mineral in pseudotachylite from South Mountain, AZ (Goodwin, 1999), the spatial resolution (equation of Merlet & Llovet, 2012, with an 80 nm diameter beam) at 7 keV for Si Ka is calculated to be 588 nm, 391 nm for Ca Ka and 641 nm for Fe La. This pseudotachylite contains abundant 5-10 um sieve-textured crystals full of inclusions with low BSE intensity. Previous 15 keV work suggested the sieve phase was amphibole. At 7 keV, it is possible to identify the compositions of the submicron inclusions as SiO2 and a K-rich alumino-silicate phase; the host composition is epidote. The enhanced resolution of FE-EPMA reveals problems with some microanalytical standards. Vicenzi and Rose (2008) showed submicron inclusions in the Smithsonian Kakanui hornblende standard. Our 7 keV experiments show the ~400 nm inclusions consist of a silicate phase (glass?), Fe-Ti oxide and possibly a gas bubble, concentrated along planes or grain boundaries. SEM imaging of an inclusion analyzed with a focused FE beam shows radiating trails of debris on the hornblende host, consistent with residue from a popped vapor bubble in the inclusion. How should FE-EPMA handle standards that may have inclusions? Use a focused beam avoiding inclusions? Sometimes, perhaps. However, we used a defocused beam to "average" the phases. The results show little or no deviation from the published wet chemical analysis. Operation at reduced keV may require use of non-traditional X-ray lines (e.g. Gopon et al, 2013 for Fe Ll vs Fe La). Experiments at 5 keV were also performed upon a synthetic material enriched in Nd (Nd-Mg-Zn). Fischer & Baun (1967) demonstrated problems with the Ma/Mb lines of REE; we find that use of the Nd Mz line is necessary in order to achieve reasonable results in this material (98 wt% total, Nd 36 wt

  7. Optical modeling of agricultural fields and rough-textured rock and mineral surfaces

    NASA Technical Reports Server (NTRS)

    Suits, G. H.; Vincent, R. K.; Horwitz, H. M.; Erickson, J. D.

    1973-01-01

    Review was made of past models for describing the reflectance and/or emittance properties of agricultural/forestry and geological targets in an effort to select the best theoretical models. An extension of the six parameter Allen-Gayle-Richardson model was chosen as the agricultural plant canopy model. The model is used to predict the bidirectional reflectance of a field crop from known laboratory spectra of crop components and approximate plant geometry. The selected geological model is based on Mie theory and radiative transfer equations, and will assess the effect of textural variations of the spectral emittance of natural rock surfaces.

  8. Deriving a per-field land use and land cover map in an agricultural mosaic catchment

    NASA Astrophysics Data System (ADS)

    Seo, B.; Bogner, C.; Poppenborg, P.; Martin, E.; Hoffmeister, M.; Jun, M.; Koellner, T.; Reineking, B.; Shope, C. L.; Tenhunen, J.

    2014-09-01

    Detailed data on land use and land cover constitute important information for Earth system models, environmental monitoring and ecosystem services research. Global land cover products are evolving rapidly; however, there is still a lack of information particularly for heterogeneous agricultural landscapes. We censused land use and land cover field by field in the agricultural mosaic catchment Haean in South Korea. We recorded the land cover types with additional information on agricultural practice. In this paper we introduce the data, their collection and the post-processing protocol. Furthermore, because it is important to quantitatively evaluate available land use and land cover products, we compared our data with the MODIS Land Cover Type product (MCD12Q1). During the studied period, a large portion of dry fields was converted to perennial crops. Compared to our data, the forested area was underrepresented and the agricultural area overrepresented in MCD12Q1. In addition, linear landscape elements such as waterbodies were missing in the MODIS product due to its coarse spatial resolution. The data presented here can be useful for earth science and ecosystem services research. The data are available at the public repository Pangaea (doi:110.1594/PANGAEA.823677).

  9. A note on elevated total gaseous mercury concentrations downwind from an agriculture field during tilling.

    PubMed

    Bash, Jesse O; Miller, David R

    2007-12-15

    Elevated mercury concentrations were measured at the University of Connecticut's mercury forest flux tower during spring agricultural field operations on an adjacent corn field. Concentrations at the tower were elevated, a peak of 7.03 ng m(-3) over the background concentration of 1.74+/-0.26 ng m(-3), during times when the prevailing wind was from the direction of the corn field and during periods when the soil was disturbed by tilling. Strong deposition to the forest was recorded at the point of measurement when atmospheric mercury concentrations were elevated. The strongest deposition rate was a 1 hour maximum of -4011 ng m(-2) h(-1) following the initial peak in atmospheric concentrations, Analyses of the meteorological conditions and mercury content in agricultural soil, manure and the diesel consumed in the tilling operation indicate that the source of the mercury was from the agricultural tilling operations and it was advected over the tower enriching the atmospheric concentrations above the forest canopy leading to deposition. These results indicate that agriculture operations resulting in a disturbed soil surface may be a source of atmospheric mercury originating from the pool of mercury bound in the soil. This represents a previously undocumented source of mercury emissions resulting from anthropogenic activities.

  10. Extraterrestrial Virtual Field Experience: Water at Meridiani

    NASA Astrophysics Data System (ADS)

    Duggan-Haas, D.; Million, C.; Sullivan, R. J., Jr.; Hayes, A. G., Jr.; Ross, R. M.; St Clair, M.

    2014-12-01

    The Spacecraft Planetary Imaging Facility (SPIF) at Cornell University, in collaboration with Million Concepts and the Paleontological Research Institute (PRI), has developed the Extraterrestrial Virtual Field Experience (EVFE), a web-based, game-like and inquiry-driven classroom activity targeted to middle school through undergraduate introductory Earth science classrooms. Students play the role of mission scientists for a NASA rover mission, tasked with targeting the rover's scientific instruments to investigate a specific scientific question about the landing site. As with the real mission, the student operators must optimize the efficient use of limited resources and time against the need to make observations to address working hypotheses. The activity uses only real--not artificial or simulated--mission data, and students are guided throughout by a "Mission Manager" who provides hints and advice about the scientific meaning of observations within the broader context of the mission objectives. The MER Opportunity EVFE is a pilot effort, the first of five EVFE modules planned a rate of one per year that will feature different NASA missions and scientific topics. The MER Opportunity EVFE has already been developed and focuses on the investigation of the history of water on Mars at the Meridiani landing site of the Opportunity rover. The module includes a teacher guide and is currently available to educators through the SPIF website.

  11. Habit versus planned behaviour: a field experiment.

    PubMed

    Verplanken, B; Aarts, H; van Knippenberg, A; Moonen, A

    1998-03-01

    A field experiment investigated the prediction and change in repeated behaviour in the domain of travel mode choices. Car use during seven days was predicted from habit strength (measured by self-reported frequency of past behaviour, as well as by a more covert measure based on personal scripts incorporating the behaviour), and antecedents of behaviour as conceptualized in the theory of planned behaviour (attitude, subjective norm, perceived behavioural control and behavioural intention). Both habit measures predicted behaviour in addition to intention and perceived control. Significant habit x intention interactions indicated that intentions were only significantly related to behaviour when habit was weak, whereas no intention-behaviour relation existed when habit was strong. During the seven-day registration of behaviour, half of the respondents were asked to think about the circumstances under which the behaviour was executed. Compared to control participants, the behaviour of experimental participants was more strongly related to their previously expressed intentions. However, the habit-behaviour relation was unaffected. The results demonstrate that, although external incentives may increase the enactment of intentions, habits set boundary conditions for the applicability of the theory of planned behaviour. PMID:9554090

  12. Designing Effective Field Experiences for Nontraditional Preservice Special Educators.

    ERIC Educational Resources Information Center

    Rosenberg, Michael S.; Jackson, Lewis; Yeh, Chyong-Hwa

    1996-01-01

    Five alternatives to traditional field experiences in special education are described and contrasted, including: infusion of experiences within content courses; traditional experiences offered during the summer session; working practica; roving practica; and specialized field-experiences. It is argued that these alternatives can provide…

  13. Long-term monitoring of nitrate transport to drainage from three agricultural clayey till fields

    NASA Astrophysics Data System (ADS)

    Ernstsen, V.; Olsen, P.; Rosenbom, A. E.

    2015-08-01

    The application of nitrogen (N) fertilisers to crops grown on tile-drained fields is required to sustain most modern crop production, but it poses a risk to the aquatic environment since tile drains facilitate rapid transport pathways with no significant reduction in nitrate. To maintain the water quality of the aquatic environment and the provision of food from highly efficient agriculture in line with the EU's Water Framework Directive and Nitrates Directive, field-scale knowledge is essential for introducing water management actions on-field or off-field and producing an optimal differentiated N-regulation in future. This study strives to provide such knowledge by evaluating on 11 years of nitrate-N concentration measurements in drainage from three subsurface-drained clayey till fields (1.3-2.3 ha) representing approximately 71 % of the surface sediments in Denmark dominated by clay. The fields differ in their inherent hydrogeological field settings (e.g. soil-type, geology, climate, drainage and groundwater table) and the agricultural management of the fields (e.g. crop type, type of N fertilisers and agricultural practices). The evaluation revealed three types of clayey till fields characterised by: (i) low net precipitation, high concentration of nitrate-N, and short-term low intensity drainage at air temperatures often below 5 °C; (ii) medium net precipitation, medium concentration of nitrate-N, and short-term medium-intensity drainage at air temperatures often above 5 °C; and (iii) high net precipitation, low concentration of nitrate-N and long-term high intensity drainage at air temperatures above 5 °C. For each type, on-field water management actions, such as the selection of crop types and introduction of catch crops, appeared relevant, whereas off-field actions only seemed relevant for the latter two field types given the temperature-dependent reduction potential of nitrate off-field. This initial well-documented field-scale knowledge from fields

  14. Deriving a per-field land use and land cover map in an agricultural mosaic catchment

    NASA Astrophysics Data System (ADS)

    Seo, B.; Bogner, C.; Poppenborg, P.; Martin, E.; Hoffmeister, M.; Jun, M.; Koellner, T.; Reineking, B.; Shope, C. L.; Tenhunen, J.

    2014-04-01

    Detailed data on land use and land cover constitutes important information for Earth system models, environmental monitoring and ecosystem services research. Global land cover products are evolving rapidly, however, there is still a lack of information particularly for heterogeneous agricultural landscapes. We censused land use and land cover field by field in an agricultural mosaic catchment Haean, South Korea. We recorded the land cover types with additional information on agricultural practice and make this data available at the public repository Pangaea (doi:10.1594/PANGAEA.823677). In this paper we introduce the data, its collection and the post-processing protocol. During the studied period, a large portion of dry fields was converted to perennial crops. A comparison between our dataset and MODIS Land Cover Type (MCD12Q1) suggested that the MODIS product was restricted in this area since it does not distinguish irrigated fields from general croplands. In addition, linear landscape elements such as water bodies were not detected in the MODIS product due to its coarse spatial resolution. The data presented here can be useful for earth science and ecosystem services research.

  15. A mobile app for delivering in-field soil data for precision agriculture

    NASA Astrophysics Data System (ADS)

    Isaacs, John P.; Stojanovic, Vladeta; Falconer, Ruth E.

    2015-04-01

    In the last decade precision agriculture has grown from a concept to an emerging technology, largely due to the maturing of GPS and mobile mapping. We investigated methods for reliable delivery and display of appropriate and context aware in-field farm data on mobile devices by developing a prototype android mobile app. The 3D app was developed using OpenGL ES 2.0 and written in Java, using the Android Development Tools (ADT) SDK. The app is able to obtain GPS coordinates and automatically synchronise the view and load relevant data based on the user's location. The intended audience of the mobile app is farmers and agronomists. Apps are becoming an essential tool in an agricultural professional's arsenal however most existing apps are limited to 2D display of data even though the modern chips in mobile devices can support the display of 3D graphics at interactive rates using technologies such as webGL. This project investigated the use of games techniques in the delivery and 3D display of field data, recognising that this may be a departure from the way the field data is currently delivered and displayed to farmers and agronomists. Different interactive 3D visualisation methods presenting spatial and temporal variation in yield values were developed and tested. It is expected that this app can be used by farmers and agronomists to support decision making in the field of precision agriculture and this is a growing market in UK and Europe.

  16. Profiling Nematode Communities in Unmanaged Flowerbed and Agricultural Field Soils in Japan by DNA Barcode Sequencing

    PubMed Central

    Morise, Hisashi; Miyazaki, Erika; Yoshimitsu, Shoko; Eki, Toshihiko

    2012-01-01

    Soil nematodes play crucial roles in the soil food web and are a suitable indicator for assessing soil environments and ecosystems. Previous nematode community analyses based on nematode morphology classification have been shown to be useful for assessing various soil environments. Here we have conducted DNA barcode analysis for soil nematode community analyses in Japanese soils. We isolated nematodes from two different environmental soils of an unmanaged flowerbed and an agricultural field using the improved flotation-sieving method. Small subunit (SSU) rDNA fragments were directly amplified from each of 68 (flowerbed samples) and 48 (field samples) isolated nematodes to determine the nucleotide sequence. Sixteen and thirteen operational taxonomic units (OTUs) were obtained by multiple sequence alignment from the flowerbed and agricultural field nematodes, respectively. All 29 SSU rDNA-derived OTUs (rOTUs) were further mapped onto a phylogenetic tree with 107 known nematode species. Interestingly, the two nematode communities examined were clearly distinct from each other in terms of trophic groups: Animal predators and plant feeders were markedly abundant in the flowerbed soils, in contrast, bacterial feeders were dominantly observed in the agricultural field soils. The data from the flowerbed nematodes suggests a possible food web among two different trophic nematode groups and plants (weeds) in the closed soil environment. Finally, DNA sequences derived from the mitochondrial cytochrome oxidase c subunit 1 (COI) gene were determined as a DNA barcode from 43 agricultural field soil nematodes. These nematodes were assigned to 13 rDNA-derived OTUs, but in the COI gene analysis were assigned to 23 COI gene-derived OTUs (cOTUs), indicating that COI gene-based barcoding may provide higher taxonomic resolution than conventional SSU rDNA-barcoding in soil nematode community analysis. PMID:23284767

  17. Profiling nematode communities in unmanaged flowerbed and agricultural field soils in Japan by DNA barcode sequencing.

    PubMed

    Morise, Hisashi; Miyazaki, Erika; Yoshimitsu, Shoko; Eki, Toshihiko

    2012-01-01

    Soil nematodes play crucial roles in the soil food web and are a suitable indicator for assessing soil environments and ecosystems. Previous nematode community analyses based on nematode morphology classification have been shown to be useful for assessing various soil environments. Here we have conducted DNA barcode analysis for soil nematode community analyses in Japanese soils. We isolated nematodes from two different environmental soils of an unmanaged flowerbed and an agricultural field using the improved flotation-sieving method. Small subunit (SSU) rDNA fragments were directly amplified from each of 68 (flowerbed samples) and 48 (field samples) isolated nematodes to determine the nucleotide sequence. Sixteen and thirteen operational taxonomic units (OTUs) were obtained by multiple sequence alignment from the flowerbed and agricultural field nematodes, respectively. All 29 SSU rDNA-derived OTUs (rOTUs) were further mapped onto a phylogenetic tree with 107 known nematode species. Interestingly, the two nematode communities examined were clearly distinct from each other in terms of trophic groups: Animal predators and plant feeders were markedly abundant in the flowerbed soils, in contrast, bacterial feeders were dominantly observed in the agricultural field soils. The data from the flowerbed nematodes suggests a possible food web among two different trophic nematode groups and plants (weeds) in the closed soil environment. Finally, DNA sequences derived from the mitochondrial cytochrome oxidase c subunit 1 (COI) gene were determined as a DNA barcode from 43 agricultural field soil nematodes. These nematodes were assigned to 13 rDNA-derived OTUs, but in the COI gene analysis were assigned to 23 COI gene-derived OTUs (cOTUs), indicating that COI gene-based barcoding may provide higher taxonomic resolution than conventional SSU rDNA-barcoding in soil nematode community analysis.

  18. Mechanisation of large-scale agricultural fields in developing countries - a review.

    PubMed

    Onwude, Daniel I; Abdulstter, Rafia; Gomes, Chandima; Hashim, Norhashila

    2016-09-01

    Mechanisation of large-scale agricultural fields often requires the application of modern technologies such as mechanical power, automation, control and robotics. These technologies are generally associated with relatively well developed economies. The application of these technologies in some developing countries in Africa and Asia is limited by factors such as technology compatibility with the environment, availability of resources to facilitate the technology adoption, cost of technology purchase, government policies, adequacy of technology and appropriateness in addressing the needs of the population. As a result, many of the available resources have been used inadequately by farmers, who continue to rely mostly on conventional means of agricultural production, using traditional tools and equipment in most cases. This has led to low productivity and high cost of production among others. Therefore this paper attempts to evaluate the application of present day technology and its limitations to the advancement of large-scale mechanisation in developing countries of Africa and Asia. Particular emphasis is given to a general understanding of the various levels of mechanisation, present day technology, its management and application to large-scale agricultural fields. This review also focuses on/gives emphasis to future outlook that will enable a gradual, evolutionary and sustainable technological change. The study concludes that large-scale-agricultural farm mechanisation for sustainable food production in Africa and Asia must be anchored on a coherent strategy based on the actual needs and priorities of the large-scale farmers. © 2016 Society of Chemical Industry.

  19. Mechanisation of large-scale agricultural fields in developing countries - a review.

    PubMed

    Onwude, Daniel I; Abdulstter, Rafia; Gomes, Chandima; Hashim, Norhashila

    2016-09-01

    Mechanisation of large-scale agricultural fields often requires the application of modern technologies such as mechanical power, automation, control and robotics. These technologies are generally associated with relatively well developed economies. The application of these technologies in some developing countries in Africa and Asia is limited by factors such as technology compatibility with the environment, availability of resources to facilitate the technology adoption, cost of technology purchase, government policies, adequacy of technology and appropriateness in addressing the needs of the population. As a result, many of the available resources have been used inadequately by farmers, who continue to rely mostly on conventional means of agricultural production, using traditional tools and equipment in most cases. This has led to low productivity and high cost of production among others. Therefore this paper attempts to evaluate the application of present day technology and its limitations to the advancement of large-scale mechanisation in developing countries of Africa and Asia. Particular emphasis is given to a general understanding of the various levels of mechanisation, present day technology, its management and application to large-scale agricultural fields. This review also focuses on/gives emphasis to future outlook that will enable a gradual, evolutionary and sustainable technological change. The study concludes that large-scale-agricultural farm mechanisation for sustainable food production in Africa and Asia must be anchored on a coherent strategy based on the actual needs and priorities of the large-scale farmers. © 2016 Society of Chemical Industry. PMID:26940194

  20. Effects of agricultural practices of three crops on the soil communities under Mediterranean conditions: field evaluation.

    NASA Astrophysics Data System (ADS)

    Leitão, Sara; José Cerejeira, Maria; Abreu, Manuela; Sousa, José Paulo

    2014-05-01

    Sustainable agricultural production relies on soil communities as the main actors in key soil processes necessary to maintain sustainable soil functioning. Soil biodiversity influences soil physical and chemical characteristics and thus the sustainability of crop and agro-ecosystems functioning. Agricultural practices (e.g.: soil tillage, pesticides and fertilizer applications, irrigation) may affects negatively or positively soil biodiversity and abundances by modifying the relationships between organisms in the soil ecosystem. The present study aimed to study the influence of agricultural practices of three crops (potato, onion and maize) under Mediterranean climate conditions on soil macro- and mesofauna during their entire crop cycles. Effects on soil communities were assessed at a higher tier of environmental risk assessment comprising field testing of indigenous edaphic communities in a selected study-site located in a major agriculture region of Central Portugal, Ribatejo e Oeste, neighbouring protected wetlands. A reference site near the agricultural field site was selected as a Control site to compare the terrestrial communities' composition and variation along the crop cycle. The field soil and Control site soil are sandy loam soils. Crops irrigation was performed by center-pivot (automated sprinkler that rotates in a half a circle area) and by sprinklers. Soil macro- and mesofauna were collected at both sites (field and Control) using two methodologies through pitfall trapping and soil sampling. The community of soil macro- and mesofauna of the three crops field varied versus control site along the crops cycles. Main differences were due to arachnids, coleopterans, ants and adult Diptera presence and abundance. The feeding activity of soil fauna between control site and crop areas varied only for potato and onion crops vs. control site but not among crops. Concentration of pesticides residues in soil did not cause apparent negative effects on the soil

  1. Assessing field vulnerability to phosphorus loss in Beijing agricultural area using Revised Field Phosphorus Ranking Scheme.

    PubMed

    Li, Qi; Chen, Li-ding; Qi, Xin; Zhang, Xin-yu; Ma, Yan; Fu, Bo-jie

    2007-01-01

    Guanting Reservoir, one of the drinking water supply sources of Beijing, suffers from water eutrophication. It is mainly supplied by Guishui River. Thus, to investigate the reasons of phosphorus (P) loss and improve the P management strategies in Guishui River watershed are important for the safety of drinking water in this region. In this study, a Revised Field P Ranking Scheme (PRS) was developed to reflect the field vulnerability of P loss at the field scale based on the Field PRS. In this new scheme, six factors are included, and each one was assigned a relative weight and a determination method. The affecting factors were classified into transport factors and source factors, and, the standards of environmental quality on surface water and soil erosion classification and degradation of the China were used in this scheme. By the new scheme, thirty-four fields in the Guishui River were categorized as "low", "medium" or "high" potential for P loss into the runoff. The results showed that the P loss risks of orchard and vegetable fields were higher than that of corn and soybean fields. The source factors were the main factors to affect P loss from the study area. In the study area, controlling P input and improving P usage efficiency are critical to decrease P loss. Based on the results, it was suggested that more attention should be paid on the fields of vegetable and orchard since they have extremely high usage rate of P and high soil test of P. Compared with P surplus by field measurements, the Revised Field PRS was more suitable for reflecting the characteristics of fields, and had higher potential capacity to identify critical source areas of P loss than PRS. PMID:17966855

  2. Methane Screening in JET Reverse Field Experiments

    SciTech Connect

    J.D. Strachan; B. Alper; G. Corrigan; S.K. Erents; C. Giroud; A. Korotkov; H. Leggate; G.F. Mathews; R.A. Pitts; M. Stamp; J. Spence

    2004-05-17

    JET plasmas with reverse magnetic field feature a different SOL flow than those with normal field. The observed carbon fueling efficiency from injecting methane gas was similar in reverse and normal field. EDGE2D modeling used an externally applied force to create the SOL flows, without specifying the origin of the force. The resulting flow agreed reasonably with the experimental values between the separatrix and 4 cm mid-plane depth in the SOL. The effect of the flow on the calculated carbon screening was 5 to 15% higher carbon fueling efficiency for the low flow velocity with reverse field.

  3. Iron coated sand/glauconite filters for phosphorus removal from artificially drained agricultural fields

    NASA Astrophysics Data System (ADS)

    Vandermoere, Stany; De Neve, Stefaan

    2016-04-01

    Flanders (Belgium) is confronted with reactive phosphorus concentrations in streams and lakes which are three to four times higher than the 0.1 ppm P limit set by the Water Framework Directive. Much of the excessive P input in surface waters is derived from agriculture. Direct P input from artificially drained fields (short-circuiting the buffering capacity of the subsoil) is suspected to be one of the major sources. We aim to develop simple and cheap filters that can be directly installed in the field to reduce P concentration from the drain water. Here we report on the performance of such filters tested at lab scale. As starting materials for the P filter, iron coated sand and acid pre-treated glauconite were used. These materials, both rich in Fe, were mixed in ratios of 75/25, 65/35, 50/50 and 0/100 (iron coated sand/glauconite ratio based on weight basis) and filled in plastic tubes. A screening experiment using the constant head method with a 0.01 M CaCl2 solution containing 1 ppm P showed that all four types of mixtures reduced the P concentration in the outflowing water to almost zero, and that the 75/25, 65/35 and 0/100 mixtures had a sufficiently large hydraulic conductivity of 0.9 to 6.0 cm/min, while the hydraulic conductivity of the 50/50 mixture was too low (< 0.4 cm/min). In a second experiment the iron coated sand and acid pre-treated glauconite were mixed in ratios of 75/25, 65/35 and 0/100 and filled in the same plastic tubes as in the first experiment. Subsequently a 0.01 M CaCl2 solution containing 1 ppm P was passed through the filters over several days, in amounts equivalent to half of the yearly water volume passing through the drains. This experiment firstly showed that in all cases the hydraulic conductivity fluctuated strongly: it decreased from 4.0-6.0 cm/min to 2.0-1.5 cm/min for the 75/25 filter, and to values < 0.4 cm/min for the 65/35 filter, whereas it increased from 0.8 to 1.4 cm/min for the 0/100 filter. Secondly, we observed a

  4. A GPS Backpack System for Mapping Soil and Crop Parameters in Agricultural Fields

    NASA Astrophysics Data System (ADS)

    Stafford, J. V.; Lebars, J. M.

    Farmers are having to gather increasing amounts of data on their soils and crops. Precision agriculture metre-by-metre is based on a knowledge of the spatial variation of soil and crop parameters across a field. The data has to be spatially located and GPS is an effective way of doing this. A backpack data logging system with GPS position tagging is described which has been designed to aid a fanner in the manual collection of data.

  5. Progress in the Understanding of Narrow Directional Scattering over Agricultural Fields

    NASA Astrophysics Data System (ADS)

    Wegmuller, U.; Santoro, M.; Mattia, F.; Balenzano, A.; Satalino, G.; Marzahn, P.; Fischer, G.; Ludwig, R.; Floury, N.

    2010-12-01

    Results achieved in a comprehensive study on directional microwave scattering over agricultural fields are presented. Major progress presented includes the much improved experimental evidence achieved and significant improvements in the understanding of the scatter phenomenon through the presented scatter model. Good progress is also made in the detection of directional scattering. It is concluded that directional scattering is relevant for applications and cannot just be ignored.

  6. Measuring the Interest of German Students in Agriculture: the Role of Knowledge, Nature Experience, Disgust, and Gender

    NASA Astrophysics Data System (ADS)

    Bickel, Malte; Strack, Micha; Bögeholz, Susanne

    2015-06-01

    Modern knowledge-based societies, especially their younger members, have largely lost their bonds to farming. However, learning about agriculture and its interrelations with environmental issues may be facilitated by students' individual interests in agriculture. To date, an adequate instrument to investigate agricultural interests has been lacking. Research has infrequently considered students' interest in agricultural content areas as well as influencing factors on students' agricultural interests. In this study, a factorial design of agricultural interests was developed combining five agricultural content areas and four components of individual interest. The instrument was validated with German fifth and sixth graders ( N = 1,085) using a variance decomposition confirmatory factor analysis model. The results demonstrated a second-order factor of general agricultural interest, with animal husbandry, arable farming, vegetable and fruit cropping, primary food processing, and agricultural engineering as discrete content areas of agricultural interest. Multiple regression analyses demonstrated that prior knowledge, garden experience, and disgust sensitivity are predictors of general agricultural interest. In addition, gender influenced interest in four of the five agricultural content areas. Implications are directed at researchers, teachers, and environmental educators concerning how to trigger and develop pupils' agricultural interests.

  7. Exploring Group Cohesion in a Higher Education Field Experience

    ERIC Educational Resources Information Center

    Malcarne, Brian Keith

    2012-01-01

    The purpose of this study was to gain understanding into the experience of group cohesion for university students participating in an academic field experience. A mixed methods approach was used following a two-phase, sequential research design to help provide a more complete explanation of how group cohesion was impacted by the field experience.…

  8. Effectiveness of a Science Agricultural Summer Experience (SASE) in Recruiting Students to Natural Resources Management

    NASA Astrophysics Data System (ADS)

    Martinez, Edward; Lindline, Jennifer; Petronis, Michael S.; Pilotti, Maura

    2012-12-01

    The Bureau of Labor Statistics projects an increase in Natural Resource Management (NRM) jobs within the next 10 years due to baby-boomer retirements and a 12% increase in demand for these occupations. Despite this trend, college enrollment in NRM disciplines has declined. Even more critical is the fact that the soon-to-be-majority Hispanic population is underrepresented in NRM disciplines. The goal of the present study was to determine if an in-residence, two-week, summer science program for underrepresented minorities would not only increase interest in science, actual science knowledge, and perceived science knowledge, but also have an overall impact on underrepresented minority students' decisions to attend college, major in a scientific discipline and pursue a career in science. During a four-year period, 76 high school students participated in a Science Agricultural Summer Experience (SASE) in Northern New Mexico. A pre/post science-knowledge exam and satisfaction survey were administered to participants. We demonstrate that participants improved significantly ( p < .05) in all areas measured. In particular, comfort with science field and lab activities, science knowledge and perceived science knowledge were enhanced after exposure to the program. Students not only found science exciting and approachable after participation, but also exhibited increased interest in pursuing a degree and career in science. Of the 76 SASE participants within graduation age ( n = 44), all graduated from high school; and 86% enrolled in college. These findings suggest that the implemented SASE initiative was effective in recruiting and increasing the confidence and abilities of underrepresented minority students in science.

  9. Early Field Experience in Career and Technical Education

    ERIC Educational Resources Information Center

    Smalley, Scott Walter

    2011-01-01

    The purpose of the three studies in this dissertation was to enhance career and technical education in the area of agriculture, business, and family and consumer sciences. This dissertation contains three papers: (1) a Delphi study identifying the purpose, expected outcomes, and methods of documenting preservice teacher early field experience…

  10. Safety in High School Supervised Agricultural Experiences: Teachers' Training and Students' Injury Awareness.

    PubMed

    Pate, M L; Lawver, R G; Sorensen, T J

    2016-01-01

    This research study sought to gather evidence of school-based agriculture teachers' hazard perceptions, safety practices, training experiences, and awareness of student injuries related to supervised agricultural experience (SAE) programs. Teachers agreed that students should follow safety guidelines developed by the National Children's Center for Rural and Agricultural Safety and Health during SAE work. Approximately 66% (f = 153) of teachers reported having general training in first aid, CPR, and AED. Twenty participants (8.6%) indicated having no safety certifications or training. Abrasions, lacerations, bites/stings, and burns accounted for a majority of the student SAE-related injuries that were reported. There were 82 participants (35.5%) who stated that no injuries had been reported or they were not aware of any injuries that occurred. The majority of teachers (66%) had received some form offirst aid or first response training, but fewer teachers had received safety training for ATVs (f = 25, 10.8%), tractors (f = 48, 20.7%), and livestock (f = 39, 16.8%). Results indicated a disparity between required safe work habits and the types of hazardous tasks students should be allowed to complete alone while participating in SAE activities. It appears most responding teachers in this study agreed to allow students to operate equipment and machinery alone. Recommendations for teachers include attending professional development training specific to SAE safety and keeping records of any risk assessments conducted during SAE supervision. Further development of best practices for SAE supervision and safety are needed to assist agricultural education professionals in protecting and shaping our future leaders in agriculture.

  11. Identifying Landscape Areas Prone to Generating Storm Runoff in Central New York Agricultural Fields

    NASA Astrophysics Data System (ADS)

    Hofmeister, K.; Walter, M. T.

    2015-12-01

    Nonpoint source (NPS) pollution continues to be a leading cause of surface water degradation, especially in agricultural areas. In humid regions where variable source area (VSA) hydrology dominates storm runoff, NPS pollution is generated where VSAs coincide with polluting activities. Mapping storm runoff risks could allow for more precise and informed targeting of NPS pollution mitigation practices in agricultural landscapes. Topographic wetness indices (TWI) provide good approximations of relative soil moisture patterns and relative storm runoff risks. Simulation models are typically used in conjunction with TWIs to quantify VSA behavior. In this study we use empirically derived relationships between TWI values, volumetric water content (VWC) and rainfall frequencies to develop runoff probability maps. Rainfall and soil VWC were measured across regionally representative agricultural areas in central New York over three years (2012-2015) to determine the volume of runoff generated from agricultural fields in the area. We assumed the threshold for storm runoff occurs when the combination of antecedent soil water and rainfall are sufficient to saturate the soil. We determined that approximately 50% of the storm runoff volume is generated from 10% of the land area during spring, summer, and autumn seasons, while the risk of storm runoff generation is higher in the spring and autumn seasons than in the summer for the same area of land.

  12. Use of UAS to Support Management in Precision Agriculture: The AggieAir Experience

    NASA Astrophysics Data System (ADS)

    McKee, M.; Torres-Rua, A. F.; ELarab, M.; Hassan Esfahani, L.; Jensen, A.

    2015-12-01

    Remote sensing applications for precision agriculture depend on acquiring actionable information at high spatial resolution and at a temporal frequency appropriate for timely responses. Unmanned aerial systems (UAS) are capable of providing such imagery for use in various applications for precision agriculture (yield estimation, evapotranspiration, etc.). AggieAirTM, a UAS platform and sensory array, was designed and developed at Utah State University to acquire high-resolution imagery (0.15m -0.6 m) in the visual, near infrared, red edge, and thermal infrared spectra. Spectral data obtained from AggieAir are used to develop soil moisture, plant chlorophyll, leaf nitrogen and actual evapotranspiration estimates to support management in precision agriculture. This presentation will focus on experience in using the AggieAir system to provide information products of possible interest in precision agriculture. The discussion will include information about the direction and rate of development of UAS technology and the current and anticipated future state of the regulatory environment for use of these systems in the U.S.

  13. Field Trips as Valuable Learning Experiences in Geography Courses

    ERIC Educational Resources Information Center

    Krakowka, Amy Richmond

    2012-01-01

    Field trips have been acknowledged as valuable learning experiences in geography. This article uses Kolb's (1984) experiential learning model to discuss how students learn and how field trips can help enhance learning. Using Kolb's experiential learning theory as a guide in the design of field trips helps ensure that field trips contribute to…

  14. The JPL MSAT mobile laboratory and the pilot field experiments

    NASA Technical Reports Server (NTRS)

    Berner, Jeff B.; Emerson, Richard F.

    1988-01-01

    A Mobile Laboratory/Propagation Measurement Van (PMV) was developed to support the field experiments of the Mobile Satellite Experiment (MSAT-X) Project. This van was designed to provide flexibility, self-sufficiency and data acquisition to allow for both measurement of equipment performance and the mobile environment. The design philosophy and implementation of the PMV are described. The Pilot Field Experiments and an overall description of the three experiments in which the PMV was used are described.

  15. Minimizing magnetic fields for precision experiments

    SciTech Connect

    Altarev, I.; Fierlinger, P.; Lins, T.; Marino, M. G.; Nießen, B.; Petzoldt, G.; Reisner, M.; Stuiber, S. Sturm, M.; Taggart Singh, J.; Taubenheim, B.; Rohrer, H. K.; Schläpfer, U.

    2015-06-21

    An increasing number of measurements in fundamental and applied physics rely on magnetically shielded environments with sub nano-Tesla residual magnetic fields. State of the art magnetically shielded rooms (MSRs) consist of up to seven layers of high permeability materials in combination with highly conductive shields. Proper magnetic equilibration is crucial to obtain such low magnetic fields with small gradients in any MSR. Here, we report on a scheme to magnetically equilibrate MSRs with a 10 times reduced duration of the magnetic equilibration sequence and a significantly lower magnetic field with improved homogeneity. For the search of the neutron's electric dipole moment, our finding corresponds to a 40% improvement of the statistical reach of the measurement. However, this versatile procedure can improve the performance of any MSR for any application.

  16. Field calibration of surface: a model of agricultural chemicals in surface waters.

    PubMed

    Gustafson, D I

    1990-10-01

    Agricultural chemicals sporadically occur at detectable levels in the surface waters of intensively farmed watersheds. HSPF, a previously released model of agricultural chemicals in surface water, had been used to predict concentrations which were much higher (10 X) than those actually observed during monitoring studies. A new model, SURFACE, is described here which is much simpler than HSPF and gives better predictions of surface water concentrations. SURFACE uses PRZM, an EPA model, to calculate edge-of-field runoff losses and simple hydraulic routing algorithms to determine concentrations at the bottom of large river basins. In water systems sampled during 1985 and 1986, SURFACE predictions of annualized mean concentrations for alachlor, atrazine, cyanazine and metolachlor were within 0.09 ppb half of the time.

  17. Multiple routes of pesticide exposure for honey bees living near agricultural fields.

    PubMed

    Krupke, Christian H; Hunt, Greg J; Eitzer, Brian D; Andino, Gladys; Given, Krispn

    2012-01-01

    Populations of honey bees and other pollinators have declined worldwide in recent years. A variety of stressors have been implicated as potential causes, including agricultural pesticides. Neonicotinoid insecticides, which are widely used and highly toxic to honey bees, have been found in previous analyses of honey bee pollen and comb material. However, the routes of exposure have remained largely undefined. We used LC/MS-MS to analyze samples of honey bees, pollen stored in the hive and several potential exposure routes associated with plantings of neonicotinoid treated maize. Our results demonstrate that bees are exposed to these compounds and several other agricultural pesticides in several ways throughout the foraging period. During spring, extremely high levels of clothianidin and thiamethoxam were found in planter exhaust material produced during the planting of treated maize seed. We also found neonicotinoids in the soil of each field we sampled, including unplanted fields. Plants visited by foraging bees (dandelions) growing near these fields were found to contain neonicotinoids as well. This indicates deposition of neonicotinoids on the flowers, uptake by the root system, or both. Dead bees collected near hive entrances during the spring sampling period were found to contain clothianidin as well, although whether exposure was oral (consuming pollen) or by contact (soil/planter dust) is unclear. We also detected the insecticide clothianidin in pollen collected by bees and stored in the hive. When maize plants in our field reached anthesis, maize pollen from treated seed was found to contain clothianidin and other pesticides; and honey bees in our study readily collected maize pollen. These findings clarify some of the mechanisms by which honey bees may be exposed to agricultural pesticides throughout the growing season. These results have implications for a wide range of large-scale annual cropping systems that utilize neonicotinoid seed treatments.

  18. Multiple Routes of Pesticide Exposure for Honey Bees Living Near Agricultural Fields

    PubMed Central

    Krupke, Christian H.; Hunt, Greg J.; Eitzer, Brian D.; Andino, Gladys; Given, Krispn

    2012-01-01

    Populations of honey bees and other pollinators have declined worldwide in recent years. A variety of stressors have been implicated as potential causes, including agricultural pesticides. Neonicotinoid insecticides, which are widely used and highly toxic to honey bees, have been found in previous analyses of honey bee pollen and comb material. However, the routes of exposure have remained largely undefined. We used LC/MS-MS to analyze samples of honey bees, pollen stored in the hive and several potential exposure routes associated with plantings of neonicotinoid treated maize. Our results demonstrate that bees are exposed to these compounds and several other agricultural pesticides in several ways throughout the foraging period. During spring, extremely high levels of clothianidin and thiamethoxam were found in planter exhaust material produced during the planting of treated maize seed. We also found neonicotinoids in the soil of each field we sampled, including unplanted fields. Plants visited by foraging bees (dandelions) growing near these fields were found to contain neonicotinoids as well. This indicates deposition of neonicotinoids on the flowers, uptake by the root system, or both. Dead bees collected near hive entrances during the spring sampling period were found to contain clothianidin as well, although whether exposure was oral (consuming pollen) or by contact (soil/planter dust) is unclear. We also detected the insecticide clothianidin in pollen collected by bees and stored in the hive. When maize plants in our field reached anthesis, maize pollen from treated seed was found to contain clothianidin and other pesticides; and honey bees in our study readily collected maize pollen. These findings clarify some of the mechanisms by which honey bees may be exposed to agricultural pesticides throughout the growing season. These results have implications for a wide range of large-scale annual cropping systems that utilize neonicotinoid seed treatments. PMID

  19. The Falklands war: Army field surgical experience.

    PubMed Central

    Jackson, D. S.; Batty, C. G.; Ryan, J. M.; McGregor, W. S.

    1983-01-01

    In the recent Falklands campaign four Army Field Surgical Teams were deployed in the two phases of the war. They functioned as Advanced Surgical Centres and operated on 233 casualties. There were 3 deaths. The patterns of wounding and the methods of casualty management are discussed and compared with other recent campaigns. Images Fig. 1 PMID:6614760

  20. Reexamining the Field Experience of Preservice Teachers.

    ERIC Educational Resources Information Center

    Moore, Rita

    2003-01-01

    Investigated the teaching and learning responses of preservice teachers enrolled in a brief language arts field practicum prior to student teaching. Survey, observation, and journal data indicated that despite consistent efforts by university professors to help preservice teachers examine theory into practice during their practica, procedural…

  1. Energy integrated farm system: North Dakota State University Agricultural Experiment Station

    SciTech Connect

    Not Available

    1984-01-01

    North Dakota State University Agricultural Experiment Station, a dairy farm with wheat, barley, sugar beet, and soybean crops, is designed to conserve energy through energy integrated concepts including wind break and solar energy for heating buildings, methane digestion, and energy conservation crop practices. The integrated energy concepts to be demonstrated are: generation of methane from manure; use of a milk-to-water heat exchanger and rock-bed heat storage in dairy operations; use of a solar collector energy system for space heat in the dairy barn (calf warming); efficient solid-liquid separation in manure collection system; use of digester effluent as bedding and fertilizer; and energy conservation by improved agriculture practices, such as conservation tillage, pest management, and soil testing for efficient use of fertilizer.

  2. Edge-of-field research to quantify the impacts of agricultural practices on water quality in Ohio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drainage is needed to sustain agricultural production to meet the demands of a growing global population, but it also transports nutrients from fields to surface water bodies. The State of Ohio is facing the tremendous challenge of maintaining agricultural production while protecting the environment...

  3. Dispersion characteristics and sinks for methyl bromide vapors downwind of treated agricultural fields

    SciTech Connect

    Seiber, J.N.; Woodrow, J.E.; Dowling, K.

    1995-12-31

    A study of methyl bromide volatilization and fate from a treated agricultural field was conducted in Monterey County, California, in 1994. Air concentrations were measured above and downwind from the field with the objective of comparing vertical and horizontal flux terms. Another objective was to compare observed downwind concentrations with those predicted by the Industrial Source Complex model, to begin the process of identifying potential sinks which might scavenge methyl bromide from the atmosphere. The final objective was to determine the limit of detection of our analytical method for airborne methyl bromide using field samples representing a wide range of concentrations. A description of the methods and results of the study will be presented, along with a discussion of data quality and interpretation.

  4. In situ combustion field experiences in Venezuela

    SciTech Connect

    Villalba, M.; Estrada, M.; Bolivar, J.

    1995-02-01

    A literature review of four in situ combustion projects: in Miga, Tia Juana, Melones and Morichal fields in Venezuela was made, and a summary of these projects is presented. Reservoir description and project performance data were analyzed. The behavior of the four in situ combustion field tests can be summarized as follows: The problems most often encountered were corrosion and high temperature producing wells. The direction in which the burning front moved was guided essentially by reservoir characteristics. The produced oil was upgraded by about 4{degrees} API, and viscosity was substantially reduced. For Mirochal and Miga fields, the analyses of available information from the combustion projects indicated that the process has been successful in the affected region. Conclusions from this review indicate that the two most frequent problems encountered were operational problems in producing wells and the direction of the burning front. The heterogeneous nature of the sands probably resulted in the burning front moving in a preferential direction, hence reducing areal sweep efficiency.

  5. Assisting Your Preservice Teacher to Be Successful during Field Experiences

    ERIC Educational Resources Information Center

    Brett, Christine

    2006-01-01

    Field experience (junior practicum and student teaching) is considered by many to be the most influential part of a teacher preparation program (Cruickshank & Aramalin, 1986; Tannehill & Zakrajsek, 1988). During field experiences, preservice teachers (hereafter referred to as PSTs) are guided by a cooperating teacher (hereafter referred to as a…

  6. Characteristics of a Model Industrial Technology Education Field Experience.

    ERIC Educational Resources Information Center

    Foster, Phillip R.; Kozak, Michael R.

    1986-01-01

    This report contains selected findings from a research project that investigated field experiences in industrial technology education. Funded by the Texas Education Agency, the project addressed the identification of characteristics of a model field experience in industrial technology education. This was accomplished using the Delphi technique.…

  7. The Field Experience: Creating Successful Programs for New Teachers.

    ERIC Educational Resources Information Center

    Slick, Gloria Appelt, Ed.

    This is the first in a series of four books presenting a variety of field experience program models and philosophies that drive the programs provided to preservice teachers during their undergraduate teacher preparation. This publications focuses on developing and evaluating an effective field experience program. Several common themes emerge from…

  8. Concerns of Teacher Candidates in an Early Field Experience

    ERIC Educational Resources Information Center

    Chang, Sau Hou

    2009-01-01

    The present study examined the concerns of teacher candidates in an early field experience. Thirty-five teacher candidates completed the Teacher Concerns Checklist (TCC, Fuller & Borich, 2000) at the beginning, middle and end of their early field experiences. Results showed that teacher candidates ranked impact as the highest concern, self as the…

  9. Emerging Trends in Teacher Preparation: The Future of Field Experiences.

    ERIC Educational Resources Information Center

    Slick, Gloria Appelt, Ed.

    This is the fourth in a series of four books presenting a variety of field experience program models and philosophies that drive the programs provided to preservice teachers during their undergraduate teacher preparation. This book focuses on critical issues facing teaching education in the future, in particular field experiences. Major themes…

  10. Preparing Middle School Teachers: Using Collaborative Middle School Field Experiences.

    ERIC Educational Resources Information Center

    Ramey, Linda K.

    Wright State University, Ohio, has developed an undergraduate degree in Middle Childhood Education with extensive content preparation and initial field experiences. Participants complete an undergraduate program in two specialized areas accompanied by 15 hours of teacher education professional coursework and field experiences in urban and suburban…

  11. Contextualising Teaching and Learning in Rural Primary Schools: Using Agricultural Experience. Volume 1 [and] Volume 2. Education Research.

    ERIC Educational Resources Information Center

    Taylor, Peter; Mulhall, Abigail

    This research project examined the potential role of agricultural experiences as a vehicle for meeting the diverse learning needs of rural primary students in developing countries. Volume 1 of the project report represents a literature review that investigated a "new role" for agriculture as a key element for developing rural students' basic…

  12. Entry-Level Technical Skills That Teachers Expected Students to Learn through Supervised Agricultural Experiences (SAEs): A Modified Delphi Study

    ERIC Educational Resources Information Center

    Ramsey, Jon W.; Edwards, M. Craig

    2012-01-01

    Supervised experiences are designed to provide opportunities for the hands-on learning of skills and practices that lead to successful personal growth and future employment in an agricultural career (Talbert, Vaughn, Croom, & Lee, 2007). In the Annual Report for Agricultural Education (2005-2006), it was stated that 91% of the respondents (i.e.,…

  13. Phosphorus adsorption and desorption potential of stream sediments and field soils in agricultural watersheds.

    PubMed

    Agudelo, Sandra C; Nelson, Nathan O; Barnes, Philip L; Keane, Timothy D; Pierzynski, Gary M

    2011-01-01

    Phosphorus release from stream sediments into water could increase P loads leaving agricultural watersheds and contribute to lag-time between implementation of best management practices and improvement in water quality. Improved understanding of P release from stream sediments can assist in setting water quality goals and designing stream monitoring programs. The objective of this study was to estimate the relative potential of sediments and soils to release P to stream water in two agricultural watersheds. Stream sediments were collected from banks, pools, riffles, and depositional features. Soils were sampled from wheat, row crop, pasture, and manure-amended fields. Sediments and soils were analyzed for equilibrium P concentration at zero net P sorption (EPC0), maximum P adsorption capacity (P(max)), anion exchange extractable P (P(lab)), and degree of P saturation. Dissolved reactive P (DRP) of stream water was monitored. Stream sediment EPC0 was similar to or less than EPC0 from field soils; however, P(lab) of stream sediments was three times less than field soils. Sediments were sandy and had low P(max) due to low oxalate-extractable Fe and Al, which could be explained by stream geomorphology. Manure-amended fields had the highest EPC0 and P(lab) due to continued inputs of manure-based P; however, conventionally fertilized fields also represented an important P source due to their vast extent. Stream water DRP was similar to EPC0 of sediments during base flow and similar to EPC0 of field soils during storm flow. These results indicate that sediments in these streams are a relatively minor P source. PMID:21488503

  14. Preparing students for higher education and careers in agriculture and related fields: An ethnography of an urban charter school

    NASA Astrophysics Data System (ADS)

    Henry, Kesha Atasha

    This study explored the preparation of students for higher education and careers in agriculturally-related fields at an urban charter high school. The data were collected through interviews, observations, and field notes. The data were analyzed by qualitative methodology with phenomenology as the theoretical framework. Findings indicated that administrators thought it was important to incorporate agricultural science courses into urban school curricula. They stated that agricultural science courses gave urban students a different way of looking at science and helped to enhance the science and technology focus of the school. Further, agricultural science courses helped to break urban students' stereotypes about agriculture and helped to bring in more state funding for educational programs. However they thought that it was more challenging to teach agricultural science in urban versus rural schools and they focused more on Science, Technology, Engineering, and Mathematics (STEM) related careers. The students had mixed views about higher education and careers in agriculture. This was based on their limited knowledge and stereotypes about agricultural majors and career options. The students highlighted several key reasons why they chose to enroll in agricultural science courses. This included the benefits of dual science credits and the ability to earn an associate degree upon successful completion of their program. Students also loved science and appreciated the science intensive nature of the agricultural courses. Additionally, they thought that the agricultural science courses were better than the other optional courses. The results also showed that electronic media such as radio and TV had a negative impact on students' perceptions about higher education and careers in agriculturally-related fields. Conclusions and recommendations are presented.

  15. Integrated analysis of root microbiomes of soybean and wheat from agricultural fields

    PubMed Central

    Rascovan, Nicolás; Carbonetto, Belén; Perrig, Diego; Díaz, Marisa; Canciani, Wilter; Abalo, Matías; Alloati, Julieta; González-Anta, Gustavo; Vazquez, Martín P.

    2016-01-01

    Root associated bacteria are critical for plant growth and health. Understanding the composition and role of root microbiota is crucial toward agricultural practices that are less dependent on chemical fertilization, which has known negative effects on the environment and human health. Here we analyzed the root-associated microbiomes of soybean and wheat under agricultural field conditions. We took samples from 11 different production fields across a large geographic area. We used 16S rRNA pyrosequencing to explore root microbial communities and also obtained 2,007 bacterial isolates from rhizospheres, which were tested for the presence of plant growth promoting (PGP) traits in-vitro. We observed that pH and nitrate content correlated with beta diversity variability of rhizospheric bacterial communities despite the variable field conditions. We described the dominant bacterial groups associated to roots from both crops at a large geographic scale and we found that a high proportion of them (60–70%) showed more than 97% similarity to bacteria from the isolated collection. Moreover, we observed that 55% of the screened isolates presented PGP activities in vitro. These results are a significant step forward in understanding crop-associated microbiomes and suggest that new directions can be taken to promote crop growth and health by modulating root microbiomes. PMID:27312589

  16. The Role Of Management Of The Field-Forest Boundary In Poland's Process Of Agricultural Restructuring

    NASA Astrophysics Data System (ADS)

    Woch, Franciszek; Borek, Robert

    2015-01-01

    The aim of the work described here has been to point to the relationships between the field-forest boundary and crop productivity as regards the present agrarian land-use structure in Poland, and to provide new opportunities for arranging the agrarian process and the spatial planning of the rural landscape in the context of the sustainable shaping of the field-forest boundary. Impacts of forests and woodlands on crop productivity have been assessed using available data from relevant Polish literature. An assessment of the plot-distribution pattern characterising farms in Poland was made on the basis of reference data from the Agency for the Restructuring and Modernisation of Agriculture. Finally, the possibility of afforestation of agricultural land has been evaluated within the existing legal framework, and on the basis of available data, with attention paid to the need to include organization of the field-forest boundary within the comprehensive management and planning of rural areas, and to preserve woody elements in patchy landscapes. This all creates an opportunity to test innovative approaches to integrated land use which combines the creation of public goods and local products based on participatory learning processes that bring in local stakeholders and decision-makers.

  17. Observation of soil moisture variability in agricultural and grassland field soils using a wireless sensor network

    NASA Astrophysics Data System (ADS)

    Priesack, Eckart; Schuh, Max

    2014-05-01

    Soil moisture dynamics is a key factor of energy and matter exchange between land surface and atmosphere. Therefore long-term observation of temporal and spatial soil moisture variability is important in studying impacts of climate change on terrestrial ecosystems and their possible feedbacks to the atmosphere. Within the framework of the network of terrestrial environmental observatories TERENO we installed at the research farm Scheyern in soils of two fields (of ca. 5 ha size each) the SoilNet wireless sensor network (Biogena et al. 2010). The SoilNet in Scheyern consists of 94 sensor units, 45 for the agricultural field site and 49 for the grassland site. Each sensor unit comprises 6 SPADE sensors, two sensors placed at the depths 10, 30 and 50 cm. The SPADE sensor (sceme.de GmbH, Horn-Bad Meinberg Germany) consists of a TDT sensor to estimate volumetric soil water content from soil electrical permittivity by sending an electromagnetic signal and measuring its propagation time, which depends on the soil dielectric properties and hence on soil water content. Additionally the SPADE sensor contains a temperature sensor (DS18B20). First results obtained from the SoilNet measurements at both fields sites will be presented and discussed. The observed high temporal and spatial variability will be analysed and related to agricultural management and basic soil properties (bulk density, soil texture, organic matter content and soil hydraulic characteristics).

  18. Youth Organization and Supervised Agricultural Experience Participation as Predictors of the Career Maturity of Agricultural Education Students. Summary of Research 72.

    ERIC Educational Resources Information Center

    Bakar, Ab. Rahim; McCracken, J. David

    A study examined relationships between career maturity and participation in the Future Farmers of America (FFA) and between career maturity and participation in supervised agricultural experience (SAE). The primary hypothesis was that career maturity is positively related to participation in FFA and SAE. A cluster random sample was used with the…

  19. Distribution of selenium in soils of agricultural fields, western San Joaquin Valley, California

    USGS Publications Warehouse

    Fujii, Roger; Deverel, S.J.; Hatfield, D.B.

    1988-01-01

    Soils from three agricultural fields in the Panoche Creek alluvial fan area in the western San Joaquin Valley, California, were analyzed for soluble, adsorbed, and total concentrations of selenium (Se) to assess the distribution and forms of Se in relation to the leaching of Se from soils. This assessment is needed to evaluate the importance of soil Se in affecting ground water concentrations. Soil samples were collected from three fields with drainage systems of different ages (6, 15, 1.5 yr) and different Se concentrations in drain water (58, 430, 3700 µg L−1, respectively). Concentrations of soluble Se and salinity were highest in soils from the field drained for 1.5 yr and lowest in the field drained for 6 yr. Of the total concentration of soil Se from all three fields, the proportion of adsorbed and soluble Se ranged from 1 to 11% and 2 > 0.68) in saturation extracts of soils sampled from below the water table. In contrast, most soluble salts and Se apparently have been leached from the unsaturated soils in the fields drained for 6 and 15 yr. For the leached soils, dissolution and precipitation of evaporite minerals containing Se may no longer control concentrations of soluble Se.

  20. Field-reversed configuration (FRC) experiments

    NASA Astrophysics Data System (ADS)

    Siemon, R. E.; Chrien, R. E.; Hugrass, W. N.; Okada, S.; Rej, D. J.; Taggart, D. P.; Tuszewski, M.; Webster, R. B.; Wright, B. L.; Slough, J. T.

    FRCs with equilibrium separatrix radii up to 0.18 m have been formed and studied in FRX-C/LSM. For best formation conditions at low fill pressure, the particle confinement exceeds the predictions of LHD transport calculations by up to a factor of two; however, the inferred flux confinement is more anomalous than in smaller FRCs. Higher bias field produces axial shocks and degradation in confinement, while higher fill pressure results in gross fluting during formation. FRCs have been formed in TRX with s from 2 to 6. These relatively collisional FRCs exhibit flux lifetimes of 10 yields 20 kinetic growth times for the internal tilt mode. The coaxial slow source has produced annular FRCs in a coaxial coil geometry on slow time scales using low voltages.

  1. Classroom and Field Experiments for Florida's Environmental Resources.

    ERIC Educational Resources Information Center

    Lewis, Jim

    This booklet is intended to help teachers in Florida manage the growing interest in environmental education. Fourteen experiments are grouped into the environmental areas of the water cycle, groundwater, water pollution, waste and water treatment, air pollution, and field experiments. Experiments include demonstrations of the water cycle, the…

  2. A career in government: my experiences working for the U.S. Department of Agriculture-Agricultural Research Service

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The agricultural sector provides highly diverse career opportunities that include private companies, academic institutions, non-government organizations, and government agencies. One possible career path is with the Federal government which is one of the largest employers of scientists and engineers...

  3. The Ecology of Field Experience: Toward an Understanding of the Role of Field Experiences in Teacher Development.

    ERIC Educational Resources Information Center

    Zeichner, Kenneth M.

    There continues to be a great deal of debate about the role that field experiences play in teacher development and about the relative contribution of various individual and institutional factors to the socialization process. Field experiences in teacher education entail a complex set of interactions among program features, settings, and people…

  4. Plot and Catchment Scale Hydrological Impacts of Agricultural Field Boundary Features

    NASA Astrophysics Data System (ADS)

    Coates, Victoria; Pattison, Ian

    2015-04-01

    Natural flood management aims to reduce downstream flow levels by delaying the movement of water through a catchment and increasing the amount of soil infiltration. Field boundary features such as hedgerows and dry stone walls are common features in the rural landscape. It is hypothesised that there presence could reduce runoff connectivity and change the soil moisture levels by altering the soil structure and porosity. The use of larger agricultural machinery has resulted in the removal of field boundaries and the subsequent increase in field sizes over the 20th Century. This change in the rural landscape is likely to have changed the partitioning of rainfall into runoff and the hydrological pathways throughout the catchment. However, the link between field boundaries and catchment scale flood risk has not yet been proven. We aim to address this need for evidence to support natural flood management by focussing on these widespread features in the rural landscape. Firstly, we quantify the change in the density of field boundaries over the past 120 years for the Skell catchment, Northern England using historical OS maps. The analysis has shown that field size has approximately doubled in the Skell catchment since 1892, due to the removal of field boundaries. Secondly, we assess the effect of field boundaries on local soil characteristics and hydrological processes through plot scale continuous monitoring of the hydrological processes along a 20m transect through the linear boundary features. For the summer period results show that soil moisture levels are lower immediately next to the hedgerow compared to distances greater than 1m from the hedgerow. Finally, we use this data to parameterise and validate a catchment scale hydrological model. The model is then applied to test the impact of a network of field boundaries on river flow extremes at the catchment scale.

  5. Distribution of selenium in soils of agricultural fields, western San Joaquin Valley, California

    USGS Publications Warehouse

    Fujii, Roger; Deverel, S.J.; Hatfield, D.B.

    1987-01-01

    Soils from three agricultural fields in the western San Joaquin Valley were analyzed for soluble, adsorbed, and total concentrations of selenium (Se) to assess the distribution and forms of Se, and the relation of the distribution and forms of Se to the leaching of Se from soils. Soil samples were collected in three fields with drainage systems of different ages (6, 15, 1.5 yr) and different Se concentrations in drain water (58, 430, 3700 micrograms/L respectively). Preliminary methods to determine total Se and estimate adsorbed Se were developed. Of the three fields, concentrations of soluble Se and salinity were highest in soils from the field drained for 1.5 yr and lowest in the field drained for 6 yr. The field drained for 1.5 yr also had the highest concentration of total Se in soil; a median of 1.2 microgram/gm. Of the total concentration of Se in soil from all three fields, the proportion of adsorbed Se and soluble Se ranged from 1 to 11% and < 1 to 63%, respectively. Most of the variance in soluble Se is explained by salinity ( r sq > 0.68) in saturation extracts of soils sampled from below the water table, reflecting evaporative concentration of Se and salinity. In contrast, most soluble salts and Se apparently have been leached from the unsaturated soils in the fields drained for 6 and 15 yr; therefore, the correlation was lower between Se and salinity in saturation extracts of those soils (r sq < 0.33). Among soils from all three fields, the ratio of Se to salinity in saturation extracts increased with increasing salinity. (Author 's abstract)

  6. Mod-2 wind turbine field operations experiment

    NASA Technical Reports Server (NTRS)

    Gordon, L. H.

    1985-01-01

    The three-machine, 7.5 MW Goodnoe Hills located near Goldendale, Washington and is now in a research/experimental operations phase that offers a unique opportunity to study the effects of single and multiple wind turbines interacting with each other, the power grid; and the environment. Following a brief description of the turbine and project history, this paper addresses major problem areas and research and development test results. Field operations, both routine and nonroutine, are discussed. Routine operation to date has produced over 13,379,000 KWh of electrical energy during 11,064 hr of rotation. Nonroutine operation includes suspended activities caused by a crack in the low speed shaft that necessitated a redesign and reinstallation of this assembly on all three turbines. With the world's largest cluster back in full operation, two of the turbines will be operated over the next years to determine their value as energy producer. The third unit will be used primarily for conducting research tests requiring configuration changes to better understand the wind turbine technology. Technical areas summarized pertain to system performance and enhancements. Specific research tests relating to acoustics, TV interference, and wake effects conclude the paper.

  7. Trichoderma Biodiversity of Agricultural Fields in East China Reveals a Gradient Distribution of Species

    PubMed Central

    Chen, Jing; Mao, Li-Juan; Feng, Xiao-Xiao; Zhang, Chu-Long; Lin, Fu-Cheng

    2016-01-01

    We surveyed the Trichoderma (Hypocreales, Ascomycota) biodiversity in agricultural fields in four major agricultural provinces of East China. Trichoderma strains were identified based on molecular approaches and morphological characteristics. In three sampled seasons (spring, summer and autumn), 2078 strains were isolated and identified to 17 known species: T. harzianum (429 isolates), T. asperellum (425), T. hamatum (397), T. virens (340), T. koningiopsis (248), T. brevicompactum (73), T. atroviride (73), T. fertile (26), T. longibrachiatum (22), T. pleuroticola (16), T. erinaceum (16), T. oblongisporum (2), T. polysporum (2), T. spirale (2), T. capillare (2), T. velutinum (2), and T. saturnisporum (1). T. harzianum, T. asperellum, T. hamatum, and T. virens were identified as the dominant species with dominance (Y) values of 0.057, 0.052, 0.048, and 0.039, respectively. The species amount, isolate numbers and the dominant species of Trichoderma varied between provinces. Zhejiang Province has shown the highest diversity, which was reflected in the highest species amount (14) and the highest Shannon–Wiener diversity index of Trichoderma haplotypes (1.46). We observed that relative frequencies of T. hamatum and T. koningiopsis under rice soil were higher than those under wheat and maize soil, indicating the preference of Trichoderma to different crops. Remarkable seasonal variation was shown, with summer exhibiting the highest biodiversity of the studied seasons. These results show that Trichoderma biodiversity in agricultural fields varies by region, crop, and season. Zhejiang Province (the southernmost province in the investigated area) had more T. hamatum than Shandong Province (the northernmost province), not only in isolate amounts but also in haplotype amounts. Furthermore, at haplotype level, only T. hamatum showed a gradient distribution from south to north in correspondence analysis among the four dominant species. The above results would contribute to the

  8. Trichoderma Biodiversity of Agricultural Fields in East China Reveals a Gradient Distribution of Species.

    PubMed

    Jiang, Yuan; Wang, Jin-Liang; Chen, Jing; Mao, Li-Juan; Feng, Xiao-Xiao; Zhang, Chu-Long; Lin, Fu-Cheng

    2016-01-01

    We surveyed the Trichoderma (Hypocreales, Ascomycota) biodiversity in agricultural fields in four major agricultural provinces of East China. Trichoderma strains were identified based on molecular approaches and morphological characteristics. In three sampled seasons (spring, summer and autumn), 2078 strains were isolated and identified to 17 known species: T. harzianum (429 isolates), T. asperellum (425), T. hamatum (397), T. virens (340), T. koningiopsis (248), T. brevicompactum (73), T. atroviride (73), T. fertile (26), T. longibrachiatum (22), T. pleuroticola (16), T. erinaceum (16), T. oblongisporum (2), T. polysporum (2), T. spirale (2), T. capillare (2), T. velutinum (2), and T. saturnisporum (1). T. harzianum, T. asperellum, T. hamatum, and T. virens were identified as the dominant species with dominance (Y) values of 0.057, 0.052, 0.048, and 0.039, respectively. The species amount, isolate numbers and the dominant species of Trichoderma varied between provinces. Zhejiang Province has shown the highest diversity, which was reflected in the highest species amount (14) and the highest Shannon-Wiener diversity index of Trichoderma haplotypes (1.46). We observed that relative frequencies of T. hamatum and T. koningiopsis under rice soil were higher than those under wheat and maize soil, indicating the preference of Trichoderma to different crops. Remarkable seasonal variation was shown, with summer exhibiting the highest biodiversity of the studied seasons. These results show that Trichoderma biodiversity in agricultural fields varies by region, crop, and season. Zhejiang Province (the southernmost province in the investigated area) had more T. hamatum than Shandong Province (the northernmost province), not only in isolate amounts but also in haplotype amounts. Furthermore, at haplotype level, only T. hamatum showed a gradient distribution from south to north in correspondence analysis among the four dominant species. The above results would contribute to the

  9. Polyoxyethylene Tallow Amine, a Glyphosate Formulation Adjuvant: Soil Adsorption Characteristics, Degradation Profile, and Occurrence on Selected Soils from Agricultural Fields in Iowa, Illinois, Indiana, Kansas, Mississippi, and Missouri.

    PubMed

    Tush, Daniel; Meyer, Michael T

    2016-06-01

    Polyoxyethylene tallow amine (POEA) is an inert ingredient added to formulations of glyphosate, the most widely applied agricultural herbicide. POEA has been shown to have toxic effects to some aquatic organisms making the potential transport of POEA from the application site into the environment an important concern. This study characterized the adsorption of POEA to soils and assessed its occurrence and homologue distribution in agricultural soils from six states. Adsorption experiments of POEA to selected soils showed that POEA adsorbed much stronger than glyphosate; calcium chloride increased the binding of POEA; and the binding of POEA was stronger in low pH conditions. POEA was detected on a soil sample from an agricultural field near Lawrence, Kansas, but with a loss of homologues that contain alkenes. POEA was also detected on soil samples collected between February and early March from corn and soybean fields from ten different sites in five other states (Iowa, Illinois, Indiana, Missouri, Mississippi). This is the first study to characterize the adsorption of POEA to soil, the potential widespread occurrence of POEA on agricultural soils, and the persistence of the POEA homologues on agricultural soils into the following growing season. PMID:27163278

  10. On-farm bioremediation of dimethazone and trifluralin residues in runoff water from an agricultural field.

    PubMed

    Antonious, George F

    2012-01-01

    Bioremediation is the use of living organisms, primarily microorganisms, to degrade environmental contaminants into less toxic forms. Nine biobeds (ground cavity filled with a mixture of composted organic matter, topsoil, and a surface grass) were established at Kentucky State University research farm (Franklin County, KY) to study the impact of this practice on reducing surface runoff water contamination by residues of dimethazone and trifluralin herbicides arising from an agricultural field. Biobed (biofilter) systems were installed at the bottom of the slope of specially designed runoff plots to examine herbicides retention and degradation before entering streams and rivers. In addition to biobed systems, three soil management practices: municipal sewage sludge (SS), SS mixed with yard waste compost (SS + YW), and no-mulch rototilled bare soil (NM used for comparison purposes) were used to monitor the impact of soil amendments on herbicide residues in soil following natural rainfall events. Organic amendments increased soil organic matter content and herbicide residues retained in soil following rainfall events. Biobeds installed in NM soil reduced dimethazone and trifluralin by 84 and 82%, respectively in runoff water that would have been transported down the land slope of agricultural fields and contaminated natural water resources. Biobeds installed in SS and SS+YW treatments reduced dimethazone by 65 and 46% and trifluralin by 52 and 79%, respectively. These findings indicated that biobeds are effective for treating dimethazone and trifluralin residues in runoff water.

  11. Gully evolution in field crops on vertic soils under conventional agriculture

    NASA Astrophysics Data System (ADS)

    Castillo, Carlos; Pérez, Rafael; Mora, Jose; Gómez, Jose A.

    2015-04-01

    Gully erosion is a major process contributing to soil degradation on cultivated areas. Its effects are especially intense in farms under conventional agriculture characterised by the use of heavy machinery for land levelling and herbicides leading to the depletion of natural vegetation in valley locations. When the soil (e.g. vertic soils) and parent material conditions (e.g. soft erodible marls) are favourable to incision, gully features may present large dimensions, producing the loss of significant proportions of productive land. This study evaluates the evolution of several gully networks located in Córdoba (Spain) within the Campiña area (a rolling landscape on Miocene marls) with conventional agriculture and gully filling operations as the predominant farm practices. The area of the catchments ranged from 10 to 100 ha, they were covered by field crops (mostly bean, sunflower and wheat) on vertic soils. Firstly, we carried out a historical analysis of the gully development during the last six decades by aerial image interpretation. Secondly, a number of field surveys were conducted to characterise the evolution of the gully morphology in a period of five years (2010-2014). For this purpose, a range of measurement techniques were used: pole and tape, differential GPS and 3D photo-reconstruction. Finally, the influence of topography (slope and drainage area) on gully dimensions along the longitudinal profile was assessed.

  12. Earthworm tolerance to residual agricultural pesticide contamination: field and experimental assessment of detoxification capabilities.

    PubMed

    Givaudan, Nicolas; Binet, Françoise; Le Bot, Barbara; Wiegand, Claudia

    2014-09-01

    This study investigates if acclimatization to residual pesticide contamination in agricultural soils is reflected in detoxification, antioxidant enzyme activities and energy budget of earthworms. Five fields within a joint agricultural area exhibited different chemical and farming histories from conventional cultivation to organic pasture. Soil multiresidual pesticide analysis revealed up to 9 molecules including atrazine up to 2.4 ng g(-1) dry soil. Exposure history of endogeic Aporrectodea caliginosa and Allolobophora chlorotica modified their responses to pesticides. In the field, activities of soluble glutathione-S-transferases (sGST) and catalase increased with soil pesticide contamination in A. caliginosa. Pesticide stress was reflected in depletion of energy reserves in A. chlorotica. Acute exposure of pre-adapted and naïve A. caliginosa to pesticides (fungicide Opus(®), 0.1 μg active ingredient epoxiconazole g(-1) dry soil, RoundUp Flash(®), 2.5 μg active ingredient glyphosate g(-1) dry soil, and their mixture), revealed that environmental pre-exposure accelerated activation of the detoxification enzyme sGST towards epoxiconazole. PMID:24874794

  13. Natural succession impeded by smooth brome (Bromus inermis) and intermediate wheatgrass (Agropyron intermedium) in an abandoned agricultural field

    SciTech Connect

    Nelson, J.K.

    1997-11-01

    In 1975, an abandoned agricultural field at Rocky Flats Environmental Technology Site (Site) that had been cultivated for more than 38 years, was seeded with smooth brome (Bromus inermis) and intermediate wheatgrass (Agropyron intermedium). Although these species are commonly planted in reclamation and roadside seed mixtures, few studies have documented their impact on the re-establishment of native plant communities. In 1994, species richness, cover, and biomass were sampled in the agricultural field and compared to the surrounding mixed-grass prairie at the Site. The agricultural field contained only 61 plant species (62% native), compared to 143 species (81% native) in the surrounding mixed-grass prairie. Community similarity based on species presence/absence was 0.47 (Sorensen coefficient of similarity). Basal vegetative cover was 11.2% in the agricultural field and 29.1% in the mixed-grass prairie. Smooth brome and intermediate wheatgrass accounted for 93% of the relative foliar cover and 96% of the biomass in the agricultural field. The aggressive nature of these two planted species has impeded the natural succession of the agricultural field to a more native prairie community. Studies of natural succession on abandoned fields and roads in northeastern Colorado have indicated that if left alone, fields would return to their native climax state in approximately 50 years and would be approaching their native state after 20--25 years. Based on the results of this study, this agricultural field may take more than 100 years to return to a native mixed-grass prairie state and it may never achieve a native state without human intervention.

  14. A Gravitational Experiment Involving Inhomogeneous Electric Fields

    SciTech Connect

    Datta, T.; Yin Ming; Vargas, Jose

    2004-02-04

    Unification of gravitation with other forms of interactions, particularly with electromagnetism, will have tremendous impacts on technology and our understanding of nature. The economic impact of such an achievement will also be unprecedented and far more extensive than the impact experienced in the past century due to the unification of electricity with magnetism and optics. Theoretical unification of gravitation with electromagnetism using classical differential geometry has been pursued since the late nineteen twenties, when Einstein and Cartan used teleparallelism for the task. Recently, Vargas and Torr have followed the same line of research with more powerful mathematics in a more general geometric framework, which allows for the presence of other interactions. Their approach also uses Kaehler generalization of Cartan's exterior calculus, which constitutes a language appropriate for both classical and quantum physics. Given the compelling nature of teleparallelism (path-independent equality of vectors at a distance) and the problems still existing with energy-momentum in general relativity, it is important to seek experimental evidence for such expectations. Such experimental programs are likely to provide quantitative guidance to the further development of current and future theories. We too, have undertaken an experimental search for potential electrically induced gravitational (EIG) effects. This presentation describes some of the practical concerns that relates to our investigation of electrical influences on laboratory size test masses. Preliminary results, appear to indicate a correlation between the application of a spatially inhomogeneous electric field and the appearance of an additional force on the test mass. If confirmed, the presence of such a force will be consistent with the predictions of Vargas-Torr. More importantly, proven results will shed new light and clearer understanding of the interactions between gravitational and electromagnetic

  15. A Gravitational Experiment Involving Inhomogeneous Electric Fields

    NASA Astrophysics Data System (ADS)

    Datta, T.; Yin, Ming; Vargas, Jose

    2004-02-01

    Unification of gravitation with other forms of interactions, particularly with electromagnetism, will have tremendous impacts on technology and our understanding of nature. The economic impact of such an achievement will also be unprecedented and far more extensive than the impact experienced in the past century due to the unification of electricity with magnetism and optics. Theoretical unification of gravitation with electromagnetism using classical differential geometry has been pursued since the late nineteen twenties, when Einstein and Cartan used teleparallelism for the task. Recently, Vargas and Torr have followed the same line of research with more powerful mathematics in a more general geometric framework, which allows for the presence of other interactions. Their approach also uses Kähler generalization of Cartan's exterior calculus, which constitutes a language appropriate for both classical and quantum physics. Given the compelling nature of teleparallelism (path-independent equality of vectors at a distance) and the problems still existing with energy-momentum in general relativity, it is important to seek experimental evidence for such expectations. Such experimental programs are likely to provide quantitative guidance to the further development of current and future theories. We too, have undertaken an experimental search for potential electrically induced gravitational (EIG) effects. This presentation describes some of the practical concerns that relates to our investigation of electrical influences on laboratory size test masses. Preliminary results, appear to indicate a correlation between the application of a spatially inhomogeneous electric field and the appearance of an additional force on the test mass. If confirmed, the presence of such a force will be consistent with the predictions of Vargas-Torr. More importantly, proven results will shed new light and clearer understanding of the interactions between gravitational and electromagnetic

  16. Meteorological and associated data collected over agricultural fields in Pinal County, Arizona, 1989 and 1990

    USGS Publications Warehouse

    Owen-Joyce, Sandra J.; Brown, Paul W.

    1995-01-01

    Data were collected at temporary meteorological stations installed in agricultural fields in Pinal County, Arizona, to evaluate the spatial and temporal variability of point data and to examine how station location affects ground-based meteorological data and the resulting values of evapotranspiration calculated using remotely sensed multispectral data from satellites. Time-specific data were collected to correspond with satellite overpasses from April to October 1989, and June 27-28, 1990. Meteorological data consisting of air temperature, relative humidity, wind speed, solar radiation, and net radiation were collected at each station during all periods of the project. Supplementary measurements of soil temperature, soil heat flux density, and surface or canopy temperature were obtained at some locations during certain periods of the project. Additional data include information on data-collection periods, station positions, instrumentation, sensor heights, and field dimensions. Other data, which correspond to the extensive field measurements made in con- junction with satellite overpasses in 1989 and 1990, include crop type, canopy cover, canopy height, irrigation, cultivation, and orientation of rows. Field boundaries and crop types were mapped in a 2- to 3-square-kilometer area surrounding each meteorological station. Field data are presented in tabular and graphic form. Meteorological and supplementary data are available, upon request, in digital form.

  17. Emergent insect production in post-harvest flooded agricultural fields used by waterbirds

    USGS Publications Warehouse

    Moss, Richard C.; Blumenshine, Steven C.; Yee, Julie; Fleskes, Joseph P.

    2009-01-01

    California’s Tulare Lake Basin (TLB) is one of the most important waterbird areas in North America even though most wetlands there have been converted to cropland. To guide management programs promoting waterbird beneficial agriculture, which includes flooding fields between growing periods, we measured emergence rates of insects, an important waterbird food, in three crop types (tomato, wheat, alfalfa) in the TLB relative to water depth and days flooded during August–October, 2003 and 2004. We used corrected Akaike’s Information Criterion values to compare a set of models that accounted for our repeated measured data. The best model included crop type and crop type interacting with days flooded and depth flooded. Emergence rates (mg m−2 day−1) were greater in tomato than wheat or alfalfa fields, increased with days flooded in alfalfa and tomato but not wheat fields, and increased with water depth in alfalfa and wheat but not tomato fields. To investigate the relationship between the range of diel water temperatures and insect emergence rates, we rearedChironomus dilutus larvae in environmental chambers under high (15–32°C) and low fluctuation (20–26°C) temperature regimes that were associated with shallow and deep (respectively) sampling sites in our fields. Larval survival (4×) and biomass (2×) were greater in the low thermal fluctuation treatment suggesting that deeply flooded areas would support greater insect production.

  18. Effects of agricultural practices on greenhouse gas emissions (N2O, CH4 and CO2) from corn fields

    NASA Astrophysics Data System (ADS)

    Hui, D.; Wang, J.; Jima, T.; Dennis, S.; Stockert, C.; Smart, D.; Bhattarai, S.; Brown, K.; Sammis, T.; Reddy, C.

    2012-12-01

    The United States is, by far, the largest producer of corn (Zea mays L.) in the world. Recent increases in fertilizer cost and concerns over global climate change have farmers and others interested in more efficient fertilization management and greenhouse gas emissions reductions. To seek the best management practices, we conducted field experiments during the 2012 growing season at Tennessee State University Agricultural Research and Demonstration Center in Nashville, TN. Six treatments were applied including regular URAN application [2 times], multiple URAN applications [4 times], denitrification inhibitor with regular URAN application, and chicken litter plus regular URAN application in no-tilled plots, and URAN application plus bio-char in tilled plots, all compared to regular URAN application in conventional tilled plots. Each treatment was replicated six times (blocks). We measured N2O, CO2 and CH4 emissions using a closed chamber method after rainfall events, fertilizer applications or every two weeks whichever was shorter. Corresponding soil NH4+-N and NO3--N, soil temperature and moisture were also measured during the gas sampling. Plant physiology and growth were measured about every two weeks. While preliminary results indicate that N2O and CO2 fluxes were significantly influenced by the agricultural practices on some days, particularly after rainfall events, CH4 flux was not influenced by the treatments during most of the days. Plots with bio-char showed significantly lower N2O emissions. We also measured N2O flux in a commercial corn field using the Eddy Covariance (EC) technique to ground verify the chamber based N2O emissions at the field scale. Results obtained with the EC technique seem comparable with the chamber method.

  19. FIELD EXPERIMENTS AND MODELING AT CDG AIRPORTS

    NASA Astrophysics Data System (ADS)

    Ramaroson, R.

    2009-12-01

    Richard Ramaroson1,4, Klaus Schaefer2, Stefan Emeis2, Carsten Jahn2, Gregor Schürmann2, Maria Hoffmann2, Mikhael Zatevakhin3, Alexandre Ignatyev3. 1ONERA, Châtillon, France; 4SEAS, Harvard University, Cambridge, USA; 2FZK, Garmisch, Germany; (3)FSUE SPbAEP, St Petersburg, Russia. 2-month field campaigns have been organized at CDG airports in autumn 2004 and summer 2005. Air quality and ground air traffic emissions have been monitored continuously at terminals and taxi-runways, along with meteorological parameters onboard trucks and with a SODAR. This paper analyses the commercial engine emissions characteristics at airports and their effects on gas pollutants and airborne particles coupled to meteorology. LES model results for PM dispersion coupled to microphysics in the PBL are compared to measurements. Winds and temperature at the surface and their vertical profiles have been stored with turbulence. SODAR observations show the time-development of the mixing layer depth and turbulent mixing in summer up to 800m. Active low level jets and their regional extent have been observed and analyzed. PM number and mass size distribution, morphology and chemical contents are investigated. Formation of new ultra fine volatile (UFV) particles in the ambient plume downstream of running engines is observed. Soot particles are mostly observed at significant level at high power thrusts at take-off (TO) and on touch-down whereas at lower thrusts at taxi and aprons ultra the UFV PM emissions become higher. Ambient airborne PM1/2.5 is closely correlated to air traffic volume and shows a maximum beside runways. PM number distribution at airports is composed mainly by volatile UF PM abundant at apron. Ambient PM mass in autumn is higher than in summer. The expected differences between TO and taxi emissions are confirmed for NO, NO2, speciated VOC and CO. NO/NO2 emissions are larger at runways due to higher power. Reactive VOC and CO are more produced at low powers during idling at

  20. Soil hydrological and soil property changes resulting from termite activity on agricultural fields in Burkina Faso

    NASA Astrophysics Data System (ADS)

    Mettrop, I.; Cammeraat, L. H.; Verbeeten, E.

    2009-04-01

    Termites are important ecosystem-engineers in subtropical and tropical regions. The effect of termite activity affecting soil infiltration is well documented in the Sahelian region. Most studies find increased infiltration rates on surfaces that are affected by termite activity in comparison to crusted areas showing non-termite presence. Crusted agricultural fields in the Sanmatenga region in Burkina Faso with clear termite activity were compared to control fields without visual ground dwelling termite activity. Fine scale rainfall simulations were carried out on crusted termite affected and control sites. Furthermore soil moisture change, bulk density, soil organic matter as well as general soil characteristics were studied. The top soils in the study area were strongly crusted (structural crust) after the summer rainfall and harvest of millet. They have a loamy sand texture underlain by a shallow sandy loam Bt horizon. The initial soil moisture conditions were significantly higher on the termite plots when compared to control sites. It was found that the amount of runoff produced on the termite plots was significantly higher, and also the volumetric soil moisture content after the experiments was significantly lower if compared to the control plots. Bulk density showed no difference whereas soil organic matter was significantly higher under termite affected areas, in comparison to the control plots. Lab tests showed no significant difference in hydrophobic behavior of the topsoil and crust material. Micro and macro-structural properties of the topsoil did not differ significantly between the termite sites and the control sites. The texture of the top 5 cm of the soil was also found to be not significantly different. The infiltration results are contradictory to the general literature, which reports increased infiltration rates after prolonged termite activity although mostly under different initial conditions. The number of nest entrances was clearly higher in

  1. Influences of suspended particles on the runoff of pesticides from an agricultural field at Askim, SE-Norway.

    PubMed

    Wu, Q; Riise, G; Lundekvam, H; Mulder, J; Haugen, L E

    2004-01-01

    Field and laboratory experiments were conducted to study the loss of particles from agricultural fields, and the role of suspended particles in carrying pesticides in surface runoff and drainage water. Propiconazole, a widely used fungicide was applied to experimental fields located at Askim, SE-Norway. Samples from surface runoff and drainage water were collected and analyzed for sediment mass, pesticides, particulate and dissolved organic carbon through a whole year. The surface soil and the runoff material were characterized by its particle size distribution, organic carbon content in size fractions and its ability to bind propiconazole. The results show that (1) particle runoff mostly occurred during the rainfall event shortly after harrowing in autumn. The highest particle concentration observed in the surface runoff water was 4600 mg l(-1), and in the drainage water 1130 mg l(-1); (2) the erosion of surface soil is size selective. The runoff sediment contained finer particle/aggregates rich in organic matter compared to its original surface soil; (3) the distribution coefficient (Kd) of propiconazole was significantly higher in the runoff sediment than in the parent soil. According to our calculation, particle-bound propiconazole can represent up to 23% of the total amount of propiconazole in a water sample with a sediment concentration of 7600 mg l(-1), which will significantly influence the transport behavior of the pesticide.

  2. A "Medical Physics" Course Based Upon Hospital Field Experience

    ERIC Educational Resources Information Center

    Onn, David G.

    1972-01-01

    Describes a noncalculus, medical physics'' course with a basic element of direct hospital field experience. The course is intended primarily for premedical students but may be taken by nonscience majors. (Author/PR)

  3. Long-term comparison of energy flux calculation methods over an agricultural field

    NASA Astrophysics Data System (ADS)

    Kolle, O.

    1996-05-01

    Since March 1990 micrometeorological measurements were carried out over an agricultural field with varying land use (wheat, barley, sunflowers, mustard) using a profile mast and an energy balance mast with an eddy correlation system for the sensible heat flux. Soil temperature, soil heat flux, soil moisture and precipitation were measured as well. Long-term measurements allow statistical analysis of the energy fluxes and comparisons of different methods for their calculation (eddy correlation, flux profile, Bowen ratio and the residual method). For the sensible heat flux a good agreement was found using these different methods after applying all necessary corrections. The latent heat flux shows greater deviations in the daily cycle between the flux profile method and the residual method due to the shape of the humidity profiles which often and especially at night show a maximum at heights between 1 m and 4 m, even if the soil is free of vegetation. This could be a consequence of the patchiness of the agricultural area, the position of the station on top of a hillock or high water absorption of the soil, respectively. The residual method seems to give more reliable results for the actual evapotranspiration than the flux profile method or the Bowen ratio method if an eddy correlation system is used to determine the sensible heat flux. Differences in the soil heat flux measured with heat flux plates and determined using the profiles of soil temperature and soil moisture can be explained by the heat flux plates being a disturbance to the soil matrix.

  4. Monitoring soil moisture dynamics via ground-penetrating radar survey of agriculture fields after irrigation

    NASA Astrophysics Data System (ADS)

    Muro, G.

    2015-12-01

    It is possible to examine the quality of ground-penetrating radar (GPR) as a measure of soil moisture content in the shallow vadose zone, where roots are most abundant and water conservation best management practices are critical in active agricultural fields. By analyzing temporal samplings of 100 Mhz reflection profiles and common-midpoint (CMP) soundings over a full growing season, the variability of vertical soil moisture distribution directly after irrigation events are characterized throughout the lifecycle of a production crop. Reflection profiles produce high-resolution travel time data and summed results of CMP sounding data provide sampling depth estimates for the weak, but coherent reflections amid strong point scatterers. The high ratio of clay in the soil limits the resolution of downward propagation of infiltrating moisture after irrigation; synthetic data analysis compared against soil moisture lysimeter logs throughout the profile allow identification of the discrete soil moisture content variation in the measured GPR data. The nature of short duration irrigation events, evapotranspiration, and drainage behavior in relation to root depths observed in the GPR temporal data allow further examination and comparison with the variable saturation model HYDRUS-1D. After retrieving soil hydraulic properties derived from laboratory measured soil samples and simplified assumptions about boundary conditions, the project aims to achieve good agreement between simulated and measured soil moisture profiles without the need for excessive model calibration for GPR-derived soil moisture estimates in an agricultural setting.

  5. Mycotoxins in the environment: I. Production and emission from an agricultural test field.

    PubMed

    Schenzel, Judith; Forrer, Hans-Rudolf; Vogelgsang, Susanne; Hungerbühler, Konrad; Bucheli, Thomas D

    2012-12-18

    Mycotoxins are secondary metabolites that are naturally produced by fungi which infest and contaminate agricultural crops and commodities (e.g., small grain cereals, fruits, vegetables, and organic soil material). Although these compounds have extensively been studied in food and feed, only little is known about their environmental fate. Therefore, we investigated over nearly two years the occurrence of various mycotoxins in a field cropped with winter wheat of the variety Levis, which was artificially inoculated with Fusarium spp., as well as their emission via drainage water. Mycotoxins were regularly quantified in whole wheat plants (0.1-133 mg/kg(dry weight), for deoxynivalenol), and drainage water samples (0.8 ng/L to 1.14 μg/L, for deoxynivalenol). From the mycotoxins quantified in wheat (3-acetyl-deoxynivalenol, deoxynivalenol, fusarenone-X, nivalenol, HT-2 toxin, T-2 toxin, beauvericin, and zearalenone), only the more hydrophilic ones or those prevailing at high concentrations were detected in drainage water. Of the total amounts produced in wheat plants (min: 2.3; max: 292 g/ha/y), 0.5-354 mg/ha/y, i.e. 0.002-0.12%, were emitted via drainage water. Hence, these compounds add to the complex mixture of natural and anthropogenic micropollutants particularly in small rural water bodies, receiving mainly runoff from agricultural areas. PMID:23145781

  6. Mycotoxins in the environment: I. Production and emission from an agricultural test field.

    PubMed

    Schenzel, Judith; Forrer, Hans-Rudolf; Vogelgsang, Susanne; Hungerbühler, Konrad; Bucheli, Thomas D

    2012-12-18

    Mycotoxins are secondary metabolites that are naturally produced by fungi which infest and contaminate agricultural crops and commodities (e.g., small grain cereals, fruits, vegetables, and organic soil material). Although these compounds have extensively been studied in food and feed, only little is known about their environmental fate. Therefore, we investigated over nearly two years the occurrence of various mycotoxins in a field cropped with winter wheat of the variety Levis, which was artificially inoculated with Fusarium spp., as well as their emission via drainage water. Mycotoxins were regularly quantified in whole wheat plants (0.1-133 mg/kg(dry weight), for deoxynivalenol), and drainage water samples (0.8 ng/L to 1.14 μg/L, for deoxynivalenol). From the mycotoxins quantified in wheat (3-acetyl-deoxynivalenol, deoxynivalenol, fusarenone-X, nivalenol, HT-2 toxin, T-2 toxin, beauvericin, and zearalenone), only the more hydrophilic ones or those prevailing at high concentrations were detected in drainage water. Of the total amounts produced in wheat plants (min: 2.3; max: 292 g/ha/y), 0.5-354 mg/ha/y, i.e. 0.002-0.12%, were emitted via drainage water. Hence, these compounds add to the complex mixture of natural and anthropogenic micropollutants particularly in small rural water bodies, receiving mainly runoff from agricultural areas.

  7. Multidisciplinary Field Training in Undergraduate Physical Geography: Russian Experience

    ERIC Educational Resources Information Center

    Kasimov, Nikolay S.; Chalov, Sergey R.; Panin, Andrey V.

    2013-01-01

    Field training is seen as a central component of the discipline of Physical Geography and an essential part of the undergraduate curriculum. This paper explores the structure and relationships between fieldwork and theoretical courses and the abundant experiences of field training in the undergraduate curriculum of 37 Russian universities. It…

  8. The Influences of University-Based Coursework on Field Experience

    ERIC Educational Resources Information Center

    Beeth, Michael E.; Adadan, Emine

    2006-01-01

    This study explored the influence of university-based teacher education courses on preservice teachers as they engaged in the field-based portion of their preparation. Forty-two preservice teachers contributed reflective writings about the successes and challenges they faced during field experiences in light of knowledge and skills learned during…

  9. Field size, length, and width distributions based on LACIE ground truth data. [large area crop inventory experiment

    NASA Technical Reports Server (NTRS)

    Pitts, D. E.; Badhwar, G.

    1980-01-01

    The development of agricultural remote sensing systems requires knowledge of agricultural field size distributions so that the sensors, sampling frames, image interpretation schemes, registration systems, and classification systems can be properly designed. Malila et al. (1976) studied the field size distribution for wheat and all other crops in two Kansas LACIE (Large Area Crop Inventory Experiment) intensive test sites using ground observations of the crops and measurements of their field areas based on current year rectified aerial photomaps. The field area and size distributions reported in the present investigation are derived from a representative subset of a stratified random sample of LACIE sample segments. In contrast to previous work, the obtained results indicate that most field-size distributions are not log-normally distributed. The most common field size observed in this study was 10 acres for most crops studied.

  10. Electric Dipole Moment Experiment Systematic from Electric Field Discharge Current

    NASA Astrophysics Data System (ADS)

    Feinberg, B.; Gould, Harvey

    2014-09-01

    A magnetic field, in the direction of the electric field and synchronous with the electric field reversal, will mimic an EDM signal. One might expect a discharge across the electric field plates to produce magnetic fields with only small or vanishing components parallel to the electric field, minimizing its systematic effect. Our experimental model, using simulated discharge currents, found otherwise: the discharge current may be at an angle to the normal, and thus generate a normal magnetic field. Comparison of data from the experimental model with the results from calculations will be presented, along with estimates of the time-averaged normal magnetic field seen by atoms in an electron EDM experiment using a fountain of laser-cooled francium, as a function of discharge current.

  11. Shared Viewing as an Approach to Transforming Early Field Experiences

    ERIC Educational Resources Information Center

    Heafner, Tina; Plaisance, Michelle

    2012-01-01

    Although early field experiences are touted as vital for providing a hands-on preview of how teaching unfolds in the classroom, these essential components of teacher preparation programs have consistently fallen short of the desired outcomes. In the spirit of Dewey, candidates need substantive experiences that transform their theoretical learning…

  12. The Impact of an International Field Experience on Preservice Teachers

    ERIC Educational Resources Information Center

    Pence, Holly M.; Macgillivray, Ian K.

    2008-01-01

    This study addresses the question, "What is the impact of an international field experience on preservice teachers?" and corroborates many of the findings of a similar study by Willard-Holt [(2001). "The impact of a short-term international experience for preservice teachers." "Teaching and Teacher Education, 17," 505-517]. In May 2005, 15 teacher…

  13. On the design of experiments to study extreme field limits

    NASA Astrophysics Data System (ADS)

    Bulanov, S. S.; Chen, M.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.; Bulanov, S. V.; Esirkepov, T. Zh.; Kando, M.; Koga, J. K.; Zhidkov, A. G.; Chen, P.; Mur, V. D.; Narozhny, N. B.; Popov, V. S.; Thomas, A. G. R.; Korn, G.

    2012-12-01

    We propose experiments on the collision of high intensity electromagnetic pulses with electron bunches and on the collision of multiple electromagnetic pulses for studying extreme field limits in the nonlinear interaction of electromagnetic waves. The effects of nonlinear QED will be revealed in these laser plasma experiments.

  14. Remote sensing experiment in West Africa. [drought effects on desert agriculture and vegetation in Niger

    NASA Technical Reports Server (NTRS)

    Macleod, N. H.

    1974-01-01

    There are substantial needs of the Sahelien Zone to detail the state of regional agricultural resources in the face of a sixth year of serious drought conditions. While most of the work has been done in the Republic of Niger, the principles which have emerged from the analysis seem to be applicable to much of the Sahel. The discussion relates to quite specific rehabilitation and development initiations under consideration in Niger which are based in part upon direct analysis of ERTS imagery of the country, in part on field surveys and on discussions with Nigerian officials and technicians. Again, because the entire Sahelien Zone (including Niger) has large zones of similar ecologic characteristics, modificiations of the approaches suggested for Niger are applicable to the solution of rehabilitation of the desert, the savannah and the woodlands of West Africa in general.

  15. On dealing with the pollution costs in agriculture: A case study of paddy fields.

    PubMed

    Yaqubi, Morteza; Shahraki, Javad; Sabouhi Sabouni, Mahmood

    2016-06-15

    The main purpose of this study is to evaluate marginal abatement cost of the main agricultural pollutants. In this sense, we construct three indices including Net Global Warming Potential (NGWP) and Nitrogen Surplus (NS), simulated by a biogeochemistry model, and also an Environmental Impact Quotient (EQI) for paddy fields. Then, using a Data Envelopment Analysis (DEA) model, we evaluate environmental inefficiencies and shadow values of these indices. The results show that there is still room for improvement at no extra cost just through a better input management. Besides, enormous potential for pollution reduction in the region is feasible. Moreover, in paddy cultivation, marginal abatement cost of pesticides and herbicides are much bigger than nitrogen surplus and greenhouse gasses. In addition, in the status quo, the mitigation costs are irrelevant to production decisions. Finally, to deal with the private pollution costs, market-based instruments are proved to be better than command-and-control regulation.

  16. On dealing with the pollution costs in agriculture: A case study of paddy fields.

    PubMed

    Yaqubi, Morteza; Shahraki, Javad; Sabouhi Sabouni, Mahmood

    2016-06-15

    The main purpose of this study is to evaluate marginal abatement cost of the main agricultural pollutants. In this sense, we construct three indices including Net Global Warming Potential (NGWP) and Nitrogen Surplus (NS), simulated by a biogeochemistry model, and also an Environmental Impact Quotient (EQI) for paddy fields. Then, using a Data Envelopment Analysis (DEA) model, we evaluate environmental inefficiencies and shadow values of these indices. The results show that there is still room for improvement at no extra cost just through a better input management. Besides, enormous potential for pollution reduction in the region is feasible. Moreover, in paddy cultivation, marginal abatement cost of pesticides and herbicides are much bigger than nitrogen surplus and greenhouse gasses. In addition, in the status quo, the mitigation costs are irrelevant to production decisions. Finally, to deal with the private pollution costs, market-based instruments are proved to be better than command-and-control regulation. PMID:26998602

  17. Agricultural soil moisture experiment, Colby, Kansas 1978: Measured and predicted hydrological properties of the soil

    NASA Technical Reports Server (NTRS)

    Arya, L. M. (Principal Investigator)

    1980-01-01

    Predictive procedures for developing soil hydrologic properties (i.e., relationships of soil water pressure and hydraulic conductivity to soil water content) are presented. Three models of the soil water pressure-water content relationship and one model of the hydraulic conductivity-water content relationship are discussed. Input requirements for the models are indicated, and computational procedures are outlined. Computed hydrologic properties for Keith silt loam, a soil typer near Colby, Kansas, on which the 1978 Agricultural Soil Moisture Experiment was conducted, are presented. A comparison of computed results with experimental data in the dry range shows that analytical models utilizing a few basic hydrophysical parameters can produce satisfactory data for large-scale applications.

  18. TEACHER'S GUIDE FOR THE EFFECTIVE USE OF "RECORDS OF SUPERVISED OCCUPATIONAL EXPERIENCE AND TRAINING IN VOCATIONAL AGRICULTURE".

    ERIC Educational Resources Information Center

    MARTIN, W. HOWARD; AND OTHERS

    A NATIONAL COMMITTEE OF TEACHERS, TEACHER EDUCATORS, AND SUPERVISORS DEVELOPED THIS TEACHER'S GUIDE TO THE "RECORDS OF SUPERVISED OCCUPATIONAL EXPERIENCE AND TRAINING IN VOCATIONAL AGRICULTURE" (VT 001 592). THE FEATURES, STUDENTS, PRINCIPLES, AND PROCEDURES OF THE EXPERIENCE PROGRAM ARE DISCUSSED. SPECIFIC DIRECTIONS AND SAMPLE ENTRIES FOR USING…

  19. Agricultural and Management Practices and Bacterial Contamination in Greenhouse versus Open Field Lettuce Production

    PubMed Central

    Holvoet, Kevin; Sampers, Imca; Seynnaeve, Marleen; Jacxsens, Liesbeth; Uyttendaele, Mieke

    2014-01-01

    The aim of this study was to gain insight into potential differences in risk factors for microbial contamination in greenhouse versus open field lettuce production. Information was collected on sources, testing, and monitoring and if applicable, treatment of irrigation and harvest rinsing water. These data were combined with results of analysis on the levels of Escherichia coli as a fecal indicator organism and the presence of enteric bacterial pathogens on both lettuce crops and environmental samples. Enterohemorragic Escherichia coli (EHEC) PCR signals (vt1 or vt2 positive and eae positive), Campylobacter spp., and Salmonella spp. isolates were more often obtained from irrigation water sampled from open field farms (21/45, 46.7%) versus from greenhouse production (9/75, 12.0%). The open field production was shown to be more prone to fecal contamination as the number of lettuce samples and irrigation water with elevated E. coli was significantly higher. Farmers comply with generic guidelines on good agricultural practices available at the national level, but monitoring of microbial quality, and if applicable appropriateness of water treatment, or water used for irrigation or at harvest is restricted. These results indicate the need for further elaboration of specific guidelines and control measures for leafy greens with regard to microbial hazards. PMID:25546272

  20. Use of airborne hyperspectral imagery to map soil parameters in tilled agricultural fields

    USGS Publications Warehouse

    Hively, W. Dean; McCarty, Gregory W.; Reeves, James B.; Lang, Megan W.; Oesterling, Robert A.; Delwiche, Stephen R.

    2011-01-01

    Soil hyperspectral reflectance imagery was obtained for six tilled (soil) agricultural fields using an airborne imaging spectrometer (400–2450 nm, ~10 nm resolution, 2.5 m spatial resolution). Surface soil samples (n = 315) were analyzed for carbon content, particle size distribution, and 15 agronomically important elements (Mehlich-III extraction). When partial least squares (PLS) regression of imagery-derived reflectance spectra was used to predict analyte concentrations, 13 of the 19 analytes were predicted with R2 > 0.50, including carbon (0.65), aluminum (0.76), iron (0.75), and silt content (0.79). Comparison of 15 spectral math preprocessing treatments showed that a simple first derivative worked well for nearly all analytes. The resulting PLS factors were exported as a vector of coefficients and used to calculate predicted maps of soil properties for each field. Image smoothing with a 3 × 3 low-pass filter prior to spectral data extraction improved prediction accuracy. The resulting raster maps showed variation associated with topographic factors, indicating the effect of soil redistribution and moisture regime on in-field spatial variability. High-resolution maps of soil analyte concentrations can be used to improve precision environmental management of farmlands.

  1. Agricultural and management practices and bacterial contamination in greenhouse versus open field lettuce production.

    PubMed

    Holvoet, Kevin; Sampers, Imca; Seynnaeve, Marleen; Jacxsens, Liesbeth; Uyttendaele, Mieke

    2014-12-23

    The aim of this study was to gain insight into potential differences in risk factors for microbial contamination in greenhouse versus open field lettuce production. Information was collected on sources, testing, and monitoring and if applicable, treatment of irrigation and harvest rinsing water. These data were combined with results of analysis on the levels of Escherichia coli as a fecal indicator organism and the presence of enteric bacterial pathogens on both lettuce crops and environmental samples. Enterohemorragic Escherichia coli (EHEC) PCR signals (vt1 or vt2 positive and eae positive), Campylobacter spp., and Salmonella spp. isolates were more often obtained from irrigation water sampled from open field farms (21/45, 46.7%) versus from greenhouse production (9/75, 12.0%). The open field production was shown to be more prone to fecal contamination as the number of lettuce samples and irrigation water with elevated E. coli was significantly higher. Farmers comply with generic guidelines on good agricultural practices available at the national level, but monitoring of microbial quality, and if applicable appropriateness of water treatment, or water used for irrigation or at harvest is restricted. These results indicate the need for further elaboration of specific guidelines and control measures for leafy greens with regard to microbial hazards.

  2. Green house gas emissions from open field burning of agricultural residues in India.

    PubMed

    Murali, S; Shrivastava, Rajnish; Saxena, Mohini

    2010-10-01

    In India, about 435.98 MMT of agro-residues are produced every year, out of which 313.62 MMT are surplus. These residues are either partially utilized or un-utilised due to various constraints. To pave the way for subsequent season for agriculture activity, the excess crop residues are burnt openly in the fields, unmindful of their ill effects on the environment. The present study has been undertaken to evaluate the severity of air pollution through emission of green house gases (GHGs) due to open field burning of agro-residues in India. Open field burning of surplus agro-residues in India results in the emission of GHG. Emissions of CH4 and N2O in 1997-98 and 2006-07 have been 3.73 and 4.06 MMT CO2 equivalent, which is an increase of 8.88% over a decade. About three-fourths of GHG emissions from agro-residues burning were CH4 and the remaining one-fourth were N2O. Burning of wheat and paddy straws alone contributes to about 42% of GHGs. These GHG emissions can be avoided once the agro-residues are employed for sustainable, cost-effective and environment- friendly options like power generation.

  3. Export of radioactive cesium from agricultural fields under simulated rainfall in Fukushima.

    PubMed

    Thai, Phong K; Suka, Yuma; Sakai, Masaru; Nanko, Kazuki; Yen, Jui-Hung; Watanabe, Hirozumi

    2015-06-01

    In this study, we investigated the impact of rainfall on runoff, soil erosion and consequently on the discharge of radioactive cesium in agricultural fields in Fukushima prefecture using a rainfall simulator. Simulated heavy rainfalls (50 mm h(-1)) generated significant runoff and soil erosion. The average concentration of radioactive cesium (the sum of (134)Cs and (137)Cs) in the runoff sediments was ∼3500 Bq kg(-1) dry soil, more than double the concentrations measured in the field soils which should be considered in studies using the (137)Cs loss to estimate long-term soil erosion. However, the estimated mass of cesium discharged through one runoff event was less than 2% of the cesium inventory in the field. This suggested that cesium discharge via soil erosion is not a significant factor in reducing the radioactivity of contaminated soils in Fukushima prefecture. However, the eroded sediment carrying radioactive cesium will deposit into the river systems and potentially pose a radioactivity risk for aquatic living organisms.

  4. Agricultural and management practices and bacterial contamination in greenhouse versus open field lettuce production.

    PubMed

    Holvoet, Kevin; Sampers, Imca; Seynnaeve, Marleen; Jacxsens, Liesbeth; Uyttendaele, Mieke

    2015-01-01

    The aim of this study was to gain insight into potential differences in risk factors for microbial contamination in greenhouse versus open field lettuce production. Information was collected on sources, testing, and monitoring and if applicable, treatment of irrigation and harvest rinsing water. These data were combined with results of analysis on the levels of Escherichia coli as a fecal indicator organism and the presence of enteric bacterial pathogens on both lettuce crops and environmental samples. Enterohemorragic Escherichia coli (EHEC) PCR signals (vt1 or vt2 positive and eae positive), Campylobacter spp., and Salmonella spp. isolates were more often obtained from irrigation water sampled from open field farms (21/45, 46.7%) versus from greenhouse production (9/75, 12.0%). The open field production was shown to be more prone to fecal contamination as the number of lettuce samples and irrigation water with elevated E. coli was significantly higher. Farmers comply with generic guidelines on good agricultural practices available at the national level, but monitoring of microbial quality, and if applicable appropriateness of water treatment, or water used for irrigation or at harvest is restricted. These results indicate the need for further elaboration of specific guidelines and control measures for leafy greens with regard to microbial hazards. PMID:25546272

  5. Evaluation of Three Models for Simulating Pesticide Runoff from Irrigated Agricultural Fields.

    PubMed

    Zhang, Xuyang; Goh, Kean S

    2015-11-01

    Three models were evaluated for their accuracy in simulating pesticide runoff at the edge of agricultural fields: Pesticide Root Zone Model (PRZM), Root Zone Water Quality Model (RZWQM), and OpusCZ. Modeling results on runoff volume, sediment erosion, and pesticide loss were compared with measurements taken from field studies. Models were also compared on their theoretical foundations and ease of use. For runoff events generated by sprinkler irrigation and rainfall, all models performed equally well with small errors in simulating water, sediment, and pesticide runoff. The mean absolute percentage errors (MAPEs) were between 3 and 161%. For flood irrigation, OpusCZ simulated runoff and pesticide mass with the highest accuracy, followed by RZWQM and PRZM, likely owning to its unique hydrological algorithm for runoff simulations during flood irrigation. Simulation results from cold model runs by OpusCZ and RZWQM using measured values for model inputs matched closely to the observed values. The MAPE ranged from 28 to 384 and 42 to 168% for OpusCZ and RZWQM, respectively. These satisfactory model outputs showed the models' abilities in mimicking reality. Theoretical evaluations indicated that OpusCZ and RZWQM use mechanistic approaches for hydrology simulation, output data on a subdaily time-step, and were able to simulate management practices and subsurface flow via tile drainage. In contrast, PRZM operates at daily time-step and simulates surface runoff using the USDA Soil Conservation Service's curve number method. Among the three models, OpusCZ and RZWQM were suitable for simulating pesticide runoff in semiarid areas where agriculture is heavily dependent on irrigation.

  6. Evaluation of Three Models for Simulating Pesticide Runoff from Irrigated Agricultural Fields.

    PubMed

    Zhang, Xuyang; Goh, Kean S

    2015-11-01

    Three models were evaluated for their accuracy in simulating pesticide runoff at the edge of agricultural fields: Pesticide Root Zone Model (PRZM), Root Zone Water Quality Model (RZWQM), and OpusCZ. Modeling results on runoff volume, sediment erosion, and pesticide loss were compared with measurements taken from field studies. Models were also compared on their theoretical foundations and ease of use. For runoff events generated by sprinkler irrigation and rainfall, all models performed equally well with small errors in simulating water, sediment, and pesticide runoff. The mean absolute percentage errors (MAPEs) were between 3 and 161%. For flood irrigation, OpusCZ simulated runoff and pesticide mass with the highest accuracy, followed by RZWQM and PRZM, likely owning to its unique hydrological algorithm for runoff simulations during flood irrigation. Simulation results from cold model runs by OpusCZ and RZWQM using measured values for model inputs matched closely to the observed values. The MAPE ranged from 28 to 384 and 42 to 168% for OpusCZ and RZWQM, respectively. These satisfactory model outputs showed the models' abilities in mimicking reality. Theoretical evaluations indicated that OpusCZ and RZWQM use mechanistic approaches for hydrology simulation, output data on a subdaily time-step, and were able to simulate management practices and subsurface flow via tile drainage. In contrast, PRZM operates at daily time-step and simulates surface runoff using the USDA Soil Conservation Service's curve number method. Among the three models, OpusCZ and RZWQM were suitable for simulating pesticide runoff in semiarid areas where agriculture is heavily dependent on irrigation. PMID:26641333

  7. Identifying diffused nitrate sources in a stream in an agricultural field using a dual isotopic approach.

    PubMed

    Ding, Jingtao; Xi, Beidou; Gao, Rutai; He, Liansheng; Liu, Hongliang; Dai, Xuanli; Yu, Yijun

    2014-06-15

    Nitrate (NO3(-)) pollution is a severe problem in aquatic systems in Taihu Lake Basin in China. A dual isotope approach (δ(15)NNO3(-) and δ(18)ONO3(-)) was applied to identify diffused NO3(-) inputs in a stream in an agricultural field at the basin in 2013. The site-specific isotopic characteristics of five NO3(-) sources (atmospheric deposition, AD; NO3(-) derived from soil organic matter nitrification, NS; NO3(-) derived from chemical fertilizer nitrification, NF; groundwater, GW; and manure and sewage, M&S) were identified. NO3(-) concentrations in the stream during the rainy season [mean±standard deviation (SD)=2.5±0.4mg/L] were lower than those during the dry season (mean±SD=4.0±0.5mg/L), whereas the δ(18)ONO3(-) values during the rainy season (mean±SD=+12.3±3.6‰) were higher than those during the dry season (mean±SD=+0.9±1.9‰). Both chemical and isotopic characteristics indicated that mixing with atmospheric NO3(-) resulted in the high δ(18)O values during the rainy season, whereas NS and M&S were the dominant NO3(-) sources during the dry season. A Bayesian model was used to determine the contribution of each NO3(-) source to total stream NO3(-). Results showed that reduced N nitrification in soil zones (including soil organic matter and fertilizer) was the main NO3(-) source throughout the year. M&S contributed more NO3(-) during the dry season (22.4%) than during the rainy season (17.8%). AD generated substantial amounts of NO3(-) in May (18.4%), June (29.8%), and July (24.5%). With the assessment of temporal variation of diffused NO3(-) sources in agricultural field, improved agricultural management practices can be implemented to protect the water resource and avoid further water quality deterioration in Taihu Lake Basin. PMID:24686140

  8. Modeling HEDLA magnetic field generation experiments on laser facilities

    NASA Astrophysics Data System (ADS)

    Fatenejad, M.; Bell, A. R.; Benuzzi-Mounaix, A.; Crowston, R.; Drake, R. P.; Flocke, N.; Gregori, G.; Koenig, M.; Krauland, C.; Lamb, D.; Lee, D.; Marques, J. R.; Meinecke, J.; Miniati, F.; Murphy, C. D.; Park, H.-S.; Pelka, A.; Ravasio, A.; Remington, B.; Reville, B.; Scopatz, A.; Tzeferacos, P.; Weide, K.; Woolsey, N.; Young, R.; Yurchak, R.

    2013-03-01

    The Flash Center is engaged in a collaboration to simulate laser driven experiments aimed at understanding the generation and amplification of cosmological magnetic fields using the FLASH code. In these experiments a laser illuminates a solid plastic or graphite target launching an asymmetric blast wave into a chamber which contains either Helium or Argon at millibar pressures. Induction coils placed several centimeters away from the target detect large scale magnetic fields on the order of tens to hundreds of Gauss. The time dependence of the magnetic field is consistent with generation via the Biermann battery mechanism near the blast wave. Attempts to perform simulations of these experiments using the FLASH code have uncovered previously unreported numerical difficulties in modeling the Biermann battery mechanism near shock waves which can lead to the production of large non-physical magnetic fields. We report on these difficulties and offer a potential solution.

  9. Relations between Education and Technical Progress in Agriculture: Training of Specialists: The Sudanese Experience.

    ERIC Educational Resources Information Center

    Gutelman, Michel; And Others

    Focusing on the training of agricultural specialists (supervisors and operational technicians) in Sudan, this study identifies issues in the general agricultural situation and the type of agricultural development practiced there, the education system's output of technicians, and the degree of harmony between education and national needs. The…

  10. Comparison of equations used for estimating agricultural crop evapotranspiration with field research

    SciTech Connect

    Hill, R.W.; Johns, E.L.; Frevert, D.K.

    1983-10-01

    Research data on alfalfa water use and related yields were obtained for 10 sites in the Western United States. Similar research data was obtained for corn at eight sites. Four different types of research studies were available: lysimeter, line source sprinkler, stress plots, and farm yield. Research alfalfa yields and corresponding ET (evapotranspiration) were assumed to be 20 percent greater than field attained yields and ET, based on experience. Similarly, corn research yields and ET were assumed to be 10 percent greater than field attained yields and ET. Yield versus ET relationships were derived from the available research data.

  11. Influencing attitudes toward science through field experiences in biology

    NASA Astrophysics Data System (ADS)

    Carpenter, Deborah Mcintyre

    The purpose of this study was to determine how student attitudes toward science are influenced by field experiences in undergraduate biology courses. The study was conducted using two institutions of higher education including a 2-year lower-level and a 2-year upper-level institution. Data were collected through interviews with student participants, focus group discussions, students' journal entries, and field notes recorded by the researcher during the field activities. Photographs and video recordings were also used as documentation sources. Data were collected over a period of 34 weeks. Themes that emerged from the qualitative data included students' beliefs that field experiences (a) positively influence student motivation to learn, (b) increase student ability to learn the concepts being taught, and (c) provide opportunities for building relationships and for personal growth. The findings of the study reinforce the importance of offering field-study programs at the undergraduate level to allow undergraduate students the opportunity to experience science activities in a field setting. The research study was framed by the behavioral and developmental theories of attitude and experience including the Theory of Planned Behavior (Ajzen, 1991) and the Theory of Experiential Learning (Kolb, 1984).

  12. Magnetic field experiment for Voyagers 1 and 2

    NASA Technical Reports Server (NTRS)

    Behannon, K. W.; Aluna, M. H.; Burlaga, L. F.; Lepping, R. P.; Ness, N. F.; Neubauer, F. M.

    1977-01-01

    The magnetic field experiment to be carried on the Voyager 1 and 2 missions consists of dual low field (LFM) and high field magnetometer (HFM) systems. The dual systems provide greater reliability and, in the case of the LFM's, permit the separation of spacecraft magnetic fields from the ambient fields. Additional reliability is achieved through electronics redundancy. The wide dynamic ranges of plus or minus 0.5G for the LFM's and plus or minus 20G for the HFM's, low quantization uncertainty of plus or minus 0.002 gamma in the most sensitive (plus or minus 8 gamma) LFM range, low sensor RMS noise level of 0.006 gamma, and use of data compaction schemes to optimize the experiment information rate all combine to permit the study of a broad spectrum of phenomena during the mission. Planetary fields at Jupiter, Saturn, and possibly Uranus; satellites of these planets; solar wind and satellite interactions with the planetary fields; and the large-scale structure and microscale characteristics of the interplanetary magnetic field are studied. The interstellar field may also be measured.

  13. Agricultural non-point source pollution in the Western Coal Field region of Kentucky

    SciTech Connect

    Snell, J.D.; Sendlein, L.V.A. . Dept. of Geological Sciences)

    1993-03-01

    As part of a general plan to characterize the extent of agricultural non-point source pollution in the different physiographic regions of Kentucky, two sites located in the Western Coal Field Physiographic provinces representing farmland drained by field tiles were chosen for ground water monitoring. These two sites are similar geologically, but the levels of Nitrate-N have proven to be drastically different between the two areas. A total of 24 wells and 3 lysimeters were installed at the two sites in three nested areas. Although both study sites are located in lowland valleys in fine grained lacustrine deposits, the materials at the Hopkins County site are slightly coarser grained. The wells in Hopkins County, with the exception of the two in the riparian zone, yield water consistently and substantially higher in Nitrate-N than wells in Daviess County. The Nitrate-N levels regularly hover near or exceed the EPA limit in Hopkins County, whereas the levels in Daviess County are near and in most cases far below the 0.53 ppm background level for the region. Pesticide concentrations are minor in both areas with small spikes of contamination noted in shallow wells shortly after application. The concentration of both the pesticides and the Nitrate-N drops off quickly with depth in both counties yielding relatively clean water below the lacustrine deposits.

  14. N-C isotopic investigation of a zeolite-amended agricultural field

    NASA Astrophysics Data System (ADS)

    Ferretti, Giacomo; Natali, Claudio; Faccini, Barbara; Di Giuseppe, Dario; Bianchini, Gianluca; Coltorti, Massimo

    2016-04-01

    In this study, a C and N isotopic investigation in the soil-plant system of the ZeoLIFE project experimental field have been carried out. Since many years, natural and NH4-enriched zeolites have been used as soil amendant in agricultural context in order to reduce N losses, increase NUE (Nitrogen Use Efficiency) and crop yield. Nevertheless up to now there are no studies that, using the stable isotopes approach, highlighted the interaction between zeolites and plants in agricultural systems. The main aims of this study is to verify if natural zeolites amendment can enhance chemical fertilization efficiency and if N transfer from NH4-enriched zeolites to plants really occurs. Plants grown following traditional cultivation methods (with no zeolite addition) and plants grown on soils amended with natural and NH4-enriched zeolites (the latter obtained after mixing with pig-slurry with a very high 15N) were compared for two cultivation cycles (maize and wheat). As widely known, plants grown under conventional farming systems (use of chemical fertilizers as urea) and plants grown under organic farming can be discriminated by the isotopic signatures of plant tissues. For both years the main results of the study reveals that plants grown on plots amended with natural zeolites generally have their nitrogen isotopic signature more similar to that of the chemical fertilizers employed during the cultivation with respect to the plants cultivated in the non-amended plot. This suggests an enhanced N uptake by the plant from this specific N source with respect to the non-amended plot. On the other hand, plants grown on NH4-enriched zeolites registered a higher 15N, approaching the pig-slurry isotopic signature, confirming that this material can constitute an N pool for plants at least for two cultivation cycles. The distinct agricultural practices seem to be reflected in the plant physiology as recorded by the carbon discrimination factor (13C) which generally increases

  15. Field and Wind Tunnel Comparison of Four Aerosol Samplers Using Agricultural Dusts

    PubMed Central

    Reynolds, Stephen J.; Nakatsu, Jason; Tillery, Marvin; Keefe, Thomas; Mehaffy, John; Thorne, Peter S.; Donham, Kelley; Nonnenmann, Matthew; Golla, Vijay; O'shaughnessy, Patrick

    2009-01-01

    Occupational lung disease is a significant problem among agricultural workers exposed to organic dusts. Measurements of exposure in agricultural environments in the USA have traditionally been conducted using 37-mm closed-face cassettes (CFCs) and respirable Cyclones. Inhalable aerosol samplers offer significant improvement for dose estimation studies to reduce respiratory disease. The goals of this study were to determine correction factors between the inhalable samplers (IOM and Button) and the CFC and Cyclone for dusts sampled in livestock buildings and to determine whether these factors vary among livestock types. Determination of these correction factors will allow comparison between inhalable measurements and historical measurements. Ten sets of samples were collected in swine, chicken, turkey, and dairy facilities in both Colorado and Iowa. Pairs of each sampling device were attached to the front and back of a rotating mannequin. Laboratory studies using a still-air chamber and a wind tunnel provided information regarding the effect of wind speed on sampler performance. Overall, the IOM had the lowest coefficient of variation (best precision) and was least affected by changes in wind speed. The performance of the Button was negatively impacted in poultry environments where larger (feather) particulates clogged the holes in the initial screen. The CFC/IOM ratios are important for comparisons between newer and older studies. Wind speed and dust type were both important factors affecting ratios. Based on the field studies (Table 6), a ratio of 0.56 is suggested as a conversion factor for the CFC/IOM (average for all environments because of no statistical difference). Suggested conversion factors for the Button/IOM are swine (0.57), chicken (0.80), turkey (0.53), and dairy (0.67). Any attempt to apply a conversion factor between the Cyclone and inhalable samplers is not recommended. PMID:19443852

  16. Field-Scale Soil Moisture Observations in Irrigated Agriculture Fields Using the Cosmic-ray Neutron Rover

    NASA Astrophysics Data System (ADS)

    Franz, T. E.; Avery, W. A.; Finkenbiner, C. E.; Wang, T.; Brocca, L.

    2014-12-01

    Approximately 40% of global food production comes from irrigated agriculture. With the increasing demand for food even greater pressures will be placed on water resources within these systems. In this work we aimed to characterize the spatial and temporal patterns of soil moisture at the field-scale (~500 m) using the newly developed cosmic-ray neutron rover near Waco, NE. Here we mapped soil moisture of 144 quarter section fields (a mix of maize, soybean, and natural areas) each week during the 2014 growing season (May to September). The 11 x11 km study domain also contained 3 stationary cosmic-ray neutron probes for independent validation of the rover surveys. Basic statistical analysis of the domain indicated a strong inverted parabolic relationship between the mean and variance of soil moisture. The relationship between the mean and higher order moments were not as strong. Geostatistical analysis indicated the range of the soil moisture semi-variogram was significantly shorter during periods of heavy irrigation as compared to non-irrigated periods. Scaling analysis indicated strong power law behavior between the variance of soil moisture and averaging area with minimal dependence of mean soil moisture on the slope of the power law function. Statistical relationships derived from the rover dataset offer a novel set of observations that will be useful in: 1) calibrating and validating land surface models, 2) calibrating and validating crop models, 3) soil moisture covariance estimates for statistical downscaling of remote sensing products such as SMOS and SMAP, and 4) provide center-pivot scale mean soil moisture data for optimal irrigation timing and volume amounts.

  17. FLASH magnetohydrodynamic simulations of shock-generated magnetic field experiments

    NASA Astrophysics Data System (ADS)

    Tzeferacos, P.; Fatenejad, M.; Flocke, N.; Gregori, G.; Lamb, D. Q.; Lee, D.; Meinecke, J.; Scopatz, A.; Weide, K.

    2012-12-01

    We report the results of benchmark FLASH magnetohydrodynamic (MHD) simulations of experiments conducted by the University of Oxford High Energy Density Laboratory Astrophysics group and its collaborators at the Laboratoire pour l'Utilisation des Lasers Intenses (LULI). In these experiments, a long-pulse laser illuminates a target in a chamber filled with Argon gas, producing shock waves that generate magnetic fields via the Biermann battery mechanism. We first outline the implementation of 2D cylindrical geometry in the unsplit MHD solver in FLASH and present results of verification tests. We then describe the results of benchmark 2D cylindrical MHD simulations of the LULI experiments using FLASH that explore the impact of external fields along with the possibility of magnetic field amplification by turbulence that is associated with the shock waves and that is induced by a grid placed in the gas-filled chamber.

  18. Dual-permeability modeling of preferential bromide leaching from a tile-drained glacial till agricultural field

    NASA Astrophysics Data System (ADS)

    Gerke, Horst H.; Maximilian Köhne, J.

    2004-04-01

    A tile-drained agricultural field can be regarded as a 'field-scale' lysimeter that may be used to study soil water and chemical transport under relatively natural conditions. Tile discharge and effluent bromide concentrations measured in a previous field tracer experiment for a structured clayey loam at Bokhorst, Northern Germany, indicated strong preferential flow. Simulation using single domain HYDRUS numerical flow and transport model could nevertheless explain water outflow, however, completely failed to describe tile-drain leaching patterns of the conservative tracer. The objective of this paper was to analyze whether the nonequilibrium-type dual-permeability model concept could better capture soil structure related principle mechanisms of preferential leaching in the unsaturated soil at that study site. The dual-permeability model (DUAL) describes for soil matrix and fracture pore systems Darcian flow with coupled Richards' equations and convective-dispersive (CD) solute transport with coupled CD equations. The hydraulic parameters of the dual-permeability model were obtained from standard soil hydraulic measurements by adopting a bimodal fitting procedure, whereas transport parameters were inferred from soil column tracer experiments and geometrical transfer term parameters were derived using qualitative soil structure descriptions. The hydraulic conductivity Ka in the inter-domain water transfer term and the effective diffusion coefficient Da in the solute mass transfer term were calibrated by comparing simulated with measured tile flow and effluent concentrations. The DUAL approach described water flow similarly well as the single-domain model. Bromide concentrations in the tile effluent could be approximated with DUAL when decreasing the Ka and Da values by three orders of magnitude compared with the values of the soil matrix domain. The dual-permeability approach seems to reflect nonequilibrium transport mechanisms at this structured soil since it not

  19. Agricultural Production.

    ERIC Educational Resources Information Center

    Lehigh County Area Vocational-Technical School, Schnecksville, PA.

    This brochure describes the philosophy and scope of a secondary-level course in agricultural production. Addressed in the individual units of the course are the following topics: careers in agriculture and agribusiness, animal science and livestock production, agronomy, agricultural mechanics, supervised occupational experience programs, and the…

  20. Improving Agricultural Drought Monitoring in East Africa with Unbiased Rainfall Fields and Detailed Land Surface Physics

    NASA Astrophysics Data System (ADS)

    McNally, A.; Yatheendradas, S.; Peters-Lidard, C. D.; Michaelsen, J.

    2010-12-01

    Monitoring drought is particularly challenging within rainfed agricultural and pastoral systems, where it can serve the greatest need. Such locations often have sparse or non-existent ground based measurements of precipitation, evapotranspiration (ET), and soil moisture. For more effective drought monitoring with limited hydroclimate observations, we simulate land surface states using the Community Noah Land Surface Model forced with different merged rainfall products inside a Land Information System (LIS). Using model outputs we will answer the questions: How sensitive are soil moisture and ET fields to differences in rainfall forcing and model physics? What are acceptable drought-specific tradeoffs between near-real time availability and skill of rainfall data? Preliminary results with the African Rainfall Estimation Algorithm Version 2 (RFE2.0) outperformed global products, suggesting that sub-global rainfall estimates are the way forward for regional drought monitoring. Specifically, the Noah model forced with RFE2.0 better resolved the heterogeneous patterns in crop stress than the Famine Early Warning System Network (FEWS NET) operational Water Requirement Satisfaction Index (WRSI) model. To further investigate the improvement in drought monitoring while maintaining timeliness, we unbias (using Africa specific climatology) the precipitation products from CPC Merged Analysis of Precipitation (CMAP), Tropical Rainfall Measurement Mission (TRMM), and RFE2.0. The skill (relative accuracy) and reliability (average agreement) of the unbiased rainfall are calculated against an unbiased precipitation product augmented with station data from Ethiopia and Kenya. Soil moisture and ET fields from Noah are compared to the operational FEWS NET WRSI, soil water anomaly index, and the World Food Program’s Crop and Food Security Assessment Mission reports. We anticipate that the unbiased rainfall fields will improve the accuracy, spatio-temporal resolution, and

  1. Agricultural terraces montoring and modeling: a field survey in Chianti region, Firenze, Italy - First part

    NASA Astrophysics Data System (ADS)

    Preti, Federico; Caruso, Marco; Dani, Andrea; Errico, Alessandro; Guastini, Enrico; Trucchi, Paolo

    2015-04-01

    The two abstracts present the design and set-up of an experimental field plant whose aim is the study and modeling of water circulation in a terraced slope together with its influence on the stability of the retaining dry stone walls. The pilot plant is located at "Fattoria di Lamole" (Greve in Chianti, Firenze, Italy) where both ancient and recently restored or rebuilt dry stone retaining walls are present. The intense vineyards cultivation makes it very representative in terms of range of external stresses that affect both hillslopes and walls. The research is developed within a bigger framework of landscape preservation as a way to prevent hydrogeological instabilities and landslide risks. First Part A first/preliminary field survey was carried out in order to estimate the hydraulic and mechanical soil characteristics. Field saturated hydraulic conductivity measurements with the Simplified Falling Head (SFH) method on a terrace along an alignment were performed. Infiltrometer tests with a double ring device and soil texture determinations with both fine particle-size and skeleton fraction distributions were also performed. The Direct shear test on undisturbed and reconstituted soil samples will offer an estimation of the Mohr-Coulomb failure envelope parameters (friction angle and cohesion). A reference portion of a dry stone wall will be also monitored. Lateral earth pressure at backfill-retaining wall interface (compared to temperature and air pressure measured values), backfill volumetric water content (both in saturated and unsaturated states) and ground-water level are measured. Acknowledgements Italian Research Project of Relevant Interest (PRIN2010-2011), prot. 20104ALME4, National network for monitoring, modeling, and sustainable management of erosion processes in agricultural land and hilly-mountainous area

  2. NATO TG-25 joint field experiment in distributed sensor networks

    NASA Astrophysics Data System (ADS)

    Mays, Brian; Vu, Hao; Srour, Nino

    2003-09-01

    NATO's Task Group (TG-25) on acoustic and seismic sensing is responsible for assessing the potential technologies that can be cooperatively developed and shared within NATO's countries to provide effective, robust and low-cost battlefield sensor systems. The primary applications will be detection and/or classification of ground troops, ground vehicles, airborne vehicles, artillery and sniper. TG-25 has 3 main objectives: (1) to establish acoustic and seismic standards and data exchange procedures, (2) to compare, analyze, exchange, and develop analytical techniques, computational models and signal processing algorithms, and (3) to plan and conduct joint field experiments. In this paper, we discuss participation in the joint NATO field experiment conducted in France in October 2002. The experiment's goal is to demonstrate interoperability of unattended ground sensors from various participating nations. Results of the experiments will be briefed and discussed. Keywords: TG-25, unattended ground sensor, vehicle tracking

  3. Linking field observations, Landsat and MODIS data to estimate agricultural change in European Russia.

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    Agricultural reform has been one of the most important anthropogenic change processes in European Russia that has been unfolding since the formal collapse of the Soviet Union at the end of 1991. Widespread land abandonment is perhaps the most vivid side effect of the reform, even visible in synoptic imagery. Currently, Russia is transitioning into a country with an internal "archipelago" of islands of productive agriculture around cities embedded in a matrix of unproductive, abandoned lands. This heterogeneous spatial pattern is mainly driven by depopulation of the least favorable parts of the countryside, where "least favorable" is a function of fertility, remoteness, and their interaction. In this work we provide a satellite, GIS and field based overview of the current agricultural developments in Russia and look beyond the unstable period immediately following the collapse of the Soviet Union. We apply Landsat images in one of Russia's oblasts to create a detailed land cover map. We then use a logistic model to link the Landsat land cover map with the inter-annual variability in key phenological parameters calculated from MODIS to derive the percent of cropland per 500m MODIS pixel. By evaluating the phenological characteristics of the MODIS curves for each year we determine whether a pixel was actually cropped or left fallow. A comparison of satellite-estimated cropped areas with regional statistics (by rayon) revealed that the satellite estimates are highly correlated with the regional statistics for both arable lands and successfully cropped areas. We use the crop maps to determine the number of times a particular area was cropped between 2002 and 2009 by summing all the years with crops per pixel. This variable provides a good indication about the intensification and de-intensification of the Russian croplands over the last decade. We have visited several rural areas in Russia and we link the satellite data with information acquired through field interviews

  4. Effect of Biochar on Greenhouse Gas Emissions and Nitrogen Cycling in Laboratory and Field Experiments

    NASA Astrophysics Data System (ADS)

    Hagemann, Nikolas; Harter, Johannes; Kaldamukova, Radina; Ruser, Reiner; Graeff-Hönninger, Simone; Kappler, Andreas; Behrens, Sebastian

    2014-05-01

    The extensive use of nitrogen (N) fertilizers in agriculture is a major source of anthropogenic N2O emissions contributing 8% to global greenhouse gas emissions. Soil biochar amendment has been suggested as a means to reduce both CO2 and non-CO2 greenhouse gas emissions. The reduction of N2O emissions by biochar has been demonstrated repeatedly in field and laboratory experiments. However, the mechanisms of the reduction remain unclear. Further it is not known how biochar field-weathering affects GHG emissions and how agro-chemicals, such as the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP), that is often simultaneously applied together with commercial N-fertilizers, impact nitrogen transformation and N2O emissions from biochar amended soils. In order investigate the duration of the biochar effect on soil N2O emissions and its susceptibility to DMPP application we performed a microcosm and field study with a high-temperature (400 ° C) beech wood derived biochar (60 t ha-1 and 5 % (w/w) biochar in the field and microcosms, respectively). While the field site contained the biochar already for three years, soil and biochar were freshly mixed for the laboratory microcosm experiments. In both studies we quantified GHG emissions and soil nitrogen speciation (nitrate, nitrite, ammonium). While the field study was carried out over the whole vegetation period of the sunflower Helianthus annuus L., soil microcosm experiments were performed for up to 9 days at 28° C. In both experiments a N-fertilizer containing DMPP was applied either before planting of the sunflowers or at the beginning of soil microcosms incubation. Laboratory microcosm experiments were performed at 60% water filled pore space reflecting average field conditions. Our results show that biochar effectively reduced soil N2O emissions by up to 60 % in the field and in the soil microcosm experiments. No significant differences in N2O emission mitigation potential between field-aged and fresh

  5. Noncrop flowering plants restore top-down herbivore control in agricultural fields.

    PubMed

    Balmer, Oliver; Pfiffner, Lukas; Schied, Johannes; Willareth, Martin; Leimgruber, Andrea; Luka, Henryk; Traugott, Michael

    2013-08-01

    Herbivore populations are regulated by bottom-up control through food availability and quality and by top-down control through natural enemies. Intensive agricultural monocultures provide abundant food to specialized herbivores and at the same time negatively impact natural enemies because monocultures are depauperate in carbohydrate food sources required by many natural enemies. As a consequence, herbivores are released from both types of control. Diversifying intensive cropping systems with flowering plants that provide nutritional resources to natural enemies may enhance top-down control and contribute to natural herbivore regulation. We analyzed how noncrop flowering plants planted as "companion plants" inside cabbage (Brassica oleracea) fields and as margins along the fields affect the plant-herbivore-parasitoid-predator food web. We combined molecular analyses quantifying parasitism of herbivore eggs and larvae with molecular predator gut content analysis and a comprehensive predator community assessment. Planting cornflowers (Centaurea cynanus), which have been shown to attract and selectively benefit Microplitis mediator, a larval parasitoid of the cabbage moth Mamestra brassicae, between the cabbage heads shifted the balance between trophic levels. Companion plants significantly increased parasitism of herbivores by larval parasitoids and predation on herbivore eggs. They furthermore significantly affected predator species richness. These effects were present despite the different treatments being close relative to the parasitoids' mobility. These findings demonstrate that habitat manipulation can restore top-down herbivore control in intensive crops if the right resources are added. This is important because increased natural control reduces the need for pesticide input in intensive agricultural settings, with cascading positive effects on general biodiversity and the environment. Companion plants thus increase biodiversity both directly, by introducing

  6. Inorganic nitrogen inventory in a lowland heterogeneous agricultural field: implications for groundwater quality monitoring and assessment

    NASA Astrophysics Data System (ADS)

    Mastrocicco, M.; Colombani, N.; Faccini, B.; Di Giuseppe, D.; Coltorti, M.

    2012-04-01

    The inorganic nitrogen leaching from agriculture can have a severe and long-lasting effect on groundwater quality and it can also affect surface water quality since the contaminated groundwater can be discharged into drains in reclaimed lowland territories, like in the Po river delta. These lands lye below the actual sea level, thus they are continuously drained by pumping stations which collect the water from a capillary distributed network of channels and ditches. A complicating factor in understanding and quantify the effective leaching of nitrogen from agricultural fertilizers is the background ammonium presence in the sub-soils, due to peat layers, which provide a natural source of organic nitrogen slowly mineralized into ammonium. This implies that the geochemical inventory of ammonium-bearing sediments in peaty soils and sediments has an important control for the future development of groundwater quality in these areas. To estimate the mass of inorganic nitrogen present within the unsaturated zone below agricultural fields, a 6 ha wide site was characterized with high resolution core depth profiles. Cores were analyzed for inorganic nitrogen content (nitrate, nitrite and ammonium) and for bromide, used as nonreactive tracer. The soils and sediments within the site are highly heterogeneous, since many sedimentological environments overlapped during the last few centuries, creating vertical and lateral facies heteropies. These facies heteropies were reconstructed in a GIS environment via grain size analysis, soil organic matter content and detailed stratigraphic logs. The vertical distribution of inorganic nitrogen species is nitrate prevalent in the first meter of soil, where oxic condition prevailed (also induced by tillage and drains); ammonium is the major nitrogen species from 1 to 4 m below ground level. Where buried sandy sediments (paleochannels) are present beneath 1 m below ground level, nitrate can penetrate slightly deeper in the unsaturated zone

  7. Soil Science as a Field Discipline - Experiences in Iowa, USA

    NASA Astrophysics Data System (ADS)

    Burras, C. Lee

    2015-04-01

    Effective field understanding of soils is crucial. This is true everywhere but especially so in Iowa, a 15 million hectare state in the central USA's "corn belt." Iowa is intensely farmed and almost exclusively privately owned. Many regions of Iowa have had over 90% of their land area in row crops for the past 60 years. In these regions two very common land management strategies are tile drainage (1.5 million km total) and high rates of fertilization (e.g., 200 kg N/ha-yr for cropland) Iowa also has problematic environmental issues including high rates of erosion, excessive sediment and nutrient pollution in water bodies and episodic catastrophic floods. Given the preceding the Agronomy, Environmental Science and Sustainable Agriculture programs at Iowa State University (ISU) offer a strong suite of soil science classes - undergraduate through graduate. The objective of this presentation is to review selected field based soil science courses offered by those programs. This review includes contrasting and comparing campus-based and immersion classes. Immersion classes include ones offered at Iowa Lakeside Laboratory, as "soil judging" and internationally. Findings over the past 20 years are consistent. Students at all levels gain soil science knowledge, competency and confidence proportional to the amount of time spent in field activities. Furthermore their professional skepticism is sharpened. They are also preferentially hired even in career postings that do not require fieldwork. In other words, field learning results in better soil science professionals who have highly functional and sought after knowledge.

  8. Multicomponent reactive transport modeling of uranium bioremediation field experiments

    SciTech Connect

    Fang, Yilin; Yabusaki, Steven B.; Morrison, Stan J.; Amonette, James E.; Long, Philip E.

    2009-10-15

    Biostimulation field experiments with acetate amendment are being performed at a former uranium mill tailings site in Rifle, Colorado, to investigate subsurface processes controlling in situ bioremediation of uranium-contaminated groundwater. An important part of the research is identifying and quantifying field-scale models of the principal terminal electron-accepting processes (TEAPs) during biostimulation and the consequent biogeochemical impacts to the subsurface receiving environment. Integrating abiotic chemistry with the microbially mediated TEAPs in the reaction network brings into play geochemical observations (e.g., pH, alkalinity, redox potential, major ions, and secondary minerals) that the reactive transport model must recognize. These additional constraints provide for a more systematic and mechanistic interpretation of the field behaviors during biostimulation. The reaction network specification developed for the 2002 biostimulation field experiment was successfully applied without additional calibration to the 2003 and 2007 field experiments. The robustness of the model specification is significant in that 1) the 2003 biostimulation field experiment was performed with 3 times higher acetate concentrations than the previous biostimulation in the same field plot (i.e., the 2002 experiment), and 2) the 2007 field experiment was performed in a new unperturbed plot on the same site. The biogeochemical reactive transport simulations accounted for four TEAPs, two distinct functional microbial populations, two pools of bioavailable Fe(III) minerals (iron oxides and phyllosilicate iron), uranium aqueous and surface complexation, mineral precipitation, and dissolution. The conceptual model for bioavailable iron reflects recent laboratory studies with sediments from the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site that demonstrated that the bulk (~90%) of Fe(III) bioreduction is associated with the phyllosilicates rather than the iron oxides

  9. Testing the Need for Replication of Eddy Covariance Carbon Dioxide Flux Measurements over Agricultural Fields

    NASA Astrophysics Data System (ADS)

    Taylor, A. M.; Amiro, B. D.; Gervais, M.

    2015-12-01

    The eddy covariance method directly measures carbon dioxide (CO2) fluxes for long periods of time and with footprints up to hundreds of meters in size. Any ecosystem process that alters how gases and energy move between the atmosphere and soil/vegetation can affect these fluxes. Eddy covariance is vulnerable to systematic errors and uncertainy, particular through relying on assumptions about surface characteristics. Additionally, spatial variation within a site can cause more uncertainty in these measurements and lack of replication in many eddy covariance studies makes statistical analysis of carbon fluxes challenging. We tested if there are significant differences between co-located and simultaneous CO2 flux measurements over a uniform crop surface, and if the differences increase if we measure different flux footprint areas over the same field. During the summer of 2014, three matched instrumented 2.5-m high towers were co-located and then periodically separated by moving at 50 m intervals along a north-south transect on an alfalfa/trefoil field and a spring wheat field in Southern Manitoba, Canada to compare CO­2 fluxes. Georeferenced leaf area index measurements were taken in 50 m grid of each field to establish uniformity of the source/sink within a footprint. Diurnal differences of similar magnitude in the CO2 ­fluxes were found in both the co-located experiment and the spatially separated intervals. Despite rigorous calibration during the experiment, some differences were caused by the measurement systems rather than by variation within the field. Interpretation of the spatial variation in leaf area index is being used to determine the contribution caused by difference in source/sink contributions to the flux footprint areas when the towers were spatially separated.

  10. Nanotechnologies in agriculture and food - an overview of different fields of application, risk assessment and public perception.

    PubMed

    Grobe, Antje; Rissanen, Mikko E

    2012-12-01

    Nanomaterials in agriculture and food are key issues of public and regulatory interest. Over the past ten years, patents for nanotechnological applications in the field of food and agriculture have become abundant. Uncertainty prevails however regarding their current development status and presence in the consumer market. Thus, the discussion on nanotechnologies in the food sector with its specific public perception of benefits and risks and the patterns of communication are becoming similar to the debate on genetically modified organisms. The food industry's silence in communication increased mistrust of consumer organisations and policy makers. The article discusses the background of the current regulatory debates, starting with the EU recommendation for defining nanomaterials, provides an overview of possible fields of application in agriculture and food industries and discusses risk assessment and the public debate on benefits and risks. Communicative recommendations are directed at researchers, the food industry and regulators in order to increase trust both in stakeholders, risk management and regulatory processes.

  11. Electron Bernstein Wave Experiments in the MST Reversed Field Pinch

    NASA Astrophysics Data System (ADS)

    Anderson, J. K.; Cengher, M.; Chattopadhyay, P. K.; Forest, C. B.; Carter, M.; Harvey, R. W.; Pinsker, R. I.; Smirnov, A. P.

    2003-12-01

    A system to heat electrons in the Madison Symmetric Torus through the electron Bernstein wave is currently being developed. This is an attractive heating scheme for the overdense reversed field pinch plasma, where electron cyclotron heating and current drive are inaccessible. Low power experiments (˜ 1 watt) have shown that a significant fraction of launched electromagnetic power successfully couples to the electron Bernstein wave. Furthermore, these experiments have found an optimized launch with finite n⊥. Initial results from experiments at moderate power (˜ 150 kW for several milliseconds, driven by a pair of S-band traveling wave tube amplifiers) are presented.

  12. Spatial probability of soil water repellency in an abandoned agricultural field in Lithuania

    NASA Astrophysics Data System (ADS)

    Pereira, Paulo; Misiūnė, Ieva

    2015-04-01

    Water repellency is a natural soil property with implications on infiltration, erosion and plant growth. It depends on soil texture, type and amount of organic matter, fungi, microorganisms, and vegetation cover (Doerr et al., 2000). Human activities as agriculture can have implications on soil water repellency (SWR) due tillage and addition of organic compounds and fertilizers (Blanco-Canqui and Lal, 2009; Gonzalez-Penaloza et al., 2012). It is also assumed that SWR has a high small-scale variability (Doerr et al., 2000). The aim of this work is to study the spatial probability of SWR in an abandoned field testing several geostatistical methods, Organic Kriging (OK), Simple Kriging (SK), Indicator Kriging (IK), Probability Kriging (PK) and Disjunctive Kriging (DK). The study area it is located near Vilnius urban area at (54 49' N, 25 22', 104 masl) in Lithuania (Pereira and Oliva, 2013). It was designed a experimental plot with 21 m2 (07x03 m). Inside this area it was measured SWR was measured every 50 cm using the water drop penetration time (WDPT) (Wessel, 1998). A total of 105 points were measured. The probability of SWR was classified in 0 (No probability) to 1 (High probability). The methods accuracy was assessed with the cross validation method. The best interpolation method was the one with the lowest Root Mean Square Error (RMSE). The results showed that the most accurate probability method was SK (RMSE=0.436), followed by DK (RMSE=0.437), IK (RMSE=0.448), PK (RMSE=0.452) and OK (RMSE=0.537). Significant differences were identified among probability tests (Kruskal-Wallis test =199.7597 p<0.001). On average the probability of SWR was high with the OK (0.58±0.08) followed by PK (0.49±0.18), SK (0.32±0.16), DK (0.32±0.15) and IK (0.31±0.16). The most accurate probability methods predicted a lower probability of SWR in the studied plot. The spatial distribution of SWR was different according to the tested technique. Simple Kriging, DK, IK and PK methods

  13. Fundamental Experiment to Determine Escape Countermeasures for Frogs Falling into Agricultural Canals

    NASA Astrophysics Data System (ADS)

    Watabe, Keiji; Mori, Atsushi; Koizumi, Noriyuki; Takemura, Takeshi

    Frogs often drown in agricultural canals with deep concrete walls, which are installed commonly in paddy fields after land improvement projects in Japan, because they cannot escape after falling into the canal. Therefore, countermeasures that enable frogs to escape from canals are required in some rural areas. An experimental canal with partially sloped walls was used as an escape countermeasure to investigate the preferable angle of slope for the walls, water depth and flow velocity that enables Tokyo Daruma Pond Frogs (Rana porosa porosa), which have no adhesive discs, to easily escape. Walls with slopes of 30-45 degrees allowed 50-60% of frogs to escape from the experimental canals, frogs especially easily climbed the 30 degree sloped walls. When the water depth was 5 cm or flow velocity was greater than 20 cm/s, approximately 80% of the frogs moved downstream and reached the sloped walls because the frogs' toes did not reach the bottom of the canal. However, if the depth was 2 cm and the flow velocity was 5 cm/s, only 4% of the frogs climbed the sloped walls because they could move freely. The frogs appeared to not be good at long-distance swimming and could not remain a long-time under running water. Therefore, walls sloped less than 30 degrees and control of both water depth and flow velocity appears important for enabling frogs to easily escape from canals.

  14. Dynamic field-frequency lock for tracking magnetic field fluctuations in electron spin resonance experiments

    NASA Astrophysics Data System (ADS)

    Asfaw, Abraham; Tyryshkin, Alexei; Lyon, Stephen

    Global magnetic field fluctuations present significant challenges to pulsed electron spin resonance experiments on systems with long spin coherence times. We will discuss results from experiments in which we follow instantaneous changes in magnetic field by locking to the free induction decay of a proton NMR signal using a phase-locked loop. We extend conventional field-frequency locking techniques used in NMR to follow slow magnetic field drifts by using a modified Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence in which the phase of the pi-pulses follows the phase of the proton spins at all times. Hence, we retain the ability of the CPMG pulse sequence to refocus local magnetic field inhomogeneities without refocusing global magnetic field fluctuations. In contrast with conventional field-frequency locking techniques, our experiments demonstrate the potential of this method to dynamically track global magnetic field fluctuations on timescales of about 2 seconds and with rates faster than a kHz. This frequency range covers the dominant noise frequencies in our electron spin resonance experiments as previously reported.

  15. An Experiment In Field-Based Elementary Teacher Education.

    ERIC Educational Resources Information Center

    Swann, Margaret H.

    The Experimental Program in Elementary Education (EXEL) at Shepherd College in West Virginia began in 1973 with authorization by the West Virginia State Department of Education. The program was developed with the hope of producing more confident and competent teachers. EXEL provides continuous field experience from the second semester of the…

  16. Field experiments on an intelligent towed vehicle ``Flying Fish``

    SciTech Connect

    Koterayama, W.; Yamaguchi, S.; Nakamura, M.

    1995-12-31

    A depth, pitch and roll controllable towed vehicle, ``Flying Fish`` is being developed to measure the ocean current, temperature, salinity, dissolved oxygen, pH, turbidity, chlorophyll and total inorganic hydrocarbon. The first field experiments on its performance were carried out in the Japan sea last summer. The motion data of the ``Flying Fish`` are compared with those of numerical simulations.

  17. Experiments to investigate particulate materials in reduced gravity fields

    NASA Technical Reports Server (NTRS)

    Bowden, M.; Eden, H. F.; Felsenthal, P.; Glaser, P. E.; Wechsler, A. E.

    1967-01-01

    Study investigates agglomeration and macroscopic behavior in reduced gravity fields of particles of known properties by measuring and correlating thermal and acoustical properties of particulate materials. Experiment evaluations provide a basis for a particle behavior theory and measure bulk properties of particulate materials in reduced gravity.

  18. The spherical probe electric field and wave experiment. [Cluster mission

    NASA Technical Reports Server (NTRS)

    Gustafsson, G.; Aggson, T.; Bostrom, R.; Block, L. P.; Cattell, C.; Decreau, P. M. E.; Egeland, A.; Falthammar, C.-G.; Grard, R. J. L.; Gurnett, D. A.

    1988-01-01

    The experiment is designed to measure the electric field and density fluctuations with sampling rates up to 40,000 samples/sec. The description includes Langmuir sweeps that can be made to determine the electron density and temperature, the study of nonlinear processes that result in acceleration of plasma, and the analysis of large scale phenomena where all four spacecraft are needed.

  19. Nonphysical Results with the Electric-Field Mapping Experiment.

    ERIC Educational Resources Information Center

    Ayars, Eric

    1996-01-01

    Discusses the behavior of the current near the end of the paper in the electric-field mapping experiment and approaches to solving problems associated with this behavior. Presents programs that can be used to model the boundary condition computationally. (JRH)

  20. Rational Ignorance in Education: A Field Experiment in Student Plagiarism

    ERIC Educational Resources Information Center

    Dee, Thomas S.; Jacob, Brian A.

    2012-01-01

    Plagiarism appears to be a common problem among college students, yet there is little evidence on the effectiveness of interventions designed to minimize plagiarism. This study presents the results of a field experiment that evaluated the effects of a web-based educational tutorial in reducing plagiarism. We found that assignment to the treatment…

  1. Field-Based Research Experience in Earth Science Teacher Education.

    ERIC Educational Resources Information Center

    O'Neal, Michael L.

    2003-01-01

    Describes the pilot of a field-based research experience in earth science teacher education designed to produce well-prepared, scientifically and technologically literate earth science teachers through a teaching- and research-oriented partnership between in-service teachers and a university scientist-educator. Indicates that the pilot program was…

  2. Quality and Early Field Experiences: Partnering with Junior Achievement

    ERIC Educational Resources Information Center

    Piro, Jody S.; Anderson, Gina; Fredrickson, Rebecca

    2015-01-01

    This study explored the perceptions of preservice teacher candidates who participated in a pilot partnership between a public teacher education preparation program and Junior Achievement (JA). The partnership was grounded in the premise that providing early field experiences to preservice teacher candidates was a necessary requirement of quality…

  3. Conceptualizing Developmentally Responsive Teaching in Early Field Experiences

    ERIC Educational Resources Information Center

    Howell, Penny B.

    2012-01-01

    The purpose of this descriptive qualitative study was to examine case study as a pedagogical tool used to scaffold the conceptualization of developmentally responsive pedagogy for middle level preservice teachers in early field experiences. Child study projects (CSP) completed by middle level preservice candidates were analyzed to determine if…

  4. Creating Dissonance in Pre-Service Teachers' Field Experiences

    ERIC Educational Resources Information Center

    Eisenhardt, Sara; Besnoy, Kevin; Steele, Emily

    2012-01-01

    The study is practical in nature and addresses the call for investigating effective aspects of field experiences in teacher preparation. The authors designed a framework of assignments requiring the pre-service teachers to collect data about two diverse elementary students in their assigned elementary classroom during the twelve weeks of their…

  5. Development of a field worthy sensor system to monitor gaseous nitrogen transfer from agricultural cropland

    SciTech Connect

    Not Available

    1992-11-01

    Nitrogen fertilizer accounts for 25 to 33% of the energy requirements in modern crop agriculture in the world today. Energy input for the manufacture of these N fertilizers is in the range of 460 [times] 10[sup 12] Btu per year. Unfortunately, for some N sources up to 70% of this energy in the form of NK can be lost through improper application techniques and poor N management strategies. Anhydrous NH[sub 3] may be lost to the atmosphere during and after placement due to soil conditions placement. Measurement of volatile N is difficult, especially under field conditions. A precise and convenient method of measuring gaseous NH[sub 3] near and above the soil surface is prerequisite to the development and evaluation of altemative fertilizer management strategies and application techniques which can reduce the potential for significant loss. Recent advances in integrated-optic (IO) based sensing offers the potential of measuring low levels of NH[sub 3] loss from a cropping system in the range of 100 ppB. The integrated design of an IO system allows for a more durable device that can be mass produced at low cost. Under Phase I of this project, two IO devices were designed and tested: an absorption device using an oxazine dye as a waveguide coating and an interferometric device using an anilinium salt as a waveguide coating.

  6. Field Experiences Using iPads: Impact of Experience on Preservice Teachers' Beliefs

    ERIC Educational Resources Information Center

    Reese, Jill A.; Bicheler, Rachel; Robinson, Callan

    2016-01-01

    The purpose of this phenomenological case study was to investigate the lived experiences of preservice music teachers using iPads to engage secondary general music students in creating and performing music during field teaching experiences. Two questions guided this research study: (a) What are these preservice teachers' perceptions of their…

  7. THE USE OF CHEMICALS IN THE FIELD OF FARM ANIMAL HEALTH (NUTRITION, ENTOMOLOGY, PATHOLOGY). AGRICULTURAL CHEMICALS TECHNOLOGY, NUMBER 7.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center for Vocational and Technical Education.

    DEVELOPED BY A NATIONAL TASK FORCE ON THE BASIS OF STATE STUDIES, THIS MODULE IS ONE OF A SERIES DESIGNED TO ASSIST TEACHERS IN PREPARING POST-SECONDARY STUDENTS FOR AGRICULTURAL CHEMICAL OCCUPATIONS. THE SPECIFIC OBJECTIVE OF THIS MODULE IS TO PREPARE TECHNICIANS IN THE FIELD OF THE USE OF CHEMICALS FOR ANIMAL HEALTH. SECTIONS INCLUDE -- (1)…

  8. Estimation of decay rates for fecal indicator bacteria and bacterial pathogens in agricultural field-applied manure

    EPA Science Inventory

    Field-applied manure is an important source of pathogenic exposure in surface water bodies for humans and ecological receptors. We analyzed the persistence and decay of fecal indicator bacteria and bacterial pathogens from three sources (cattle, poultry, swine) for agricultural f...

  9. A Profile of Secondary Teachers and Schools in North Dakota: Implications for the Student Teaching Experience in Agricultural Education

    ERIC Educational Resources Information Center

    Young, R. Brent; Edwards, M. Craig

    2011-01-01

    This study was an inquiry of secondary teachers' perceptions of the agricultural education student teaching experience in North Dakota. The sampling frame (N = 89) included all secondary teachers in the state; the final return rate was 74%. The instrument included 16 items identifying selected characteristics of secondary teachers and their…

  10. MyAgRecord: An Online Career Portfolio Management Tool for High School Students Conducting Supervised Agricultural Experience Programs.

    ERIC Educational Resources Information Center

    Emis, Larry; Dillingham, John

    Texas's online career portfolio management tool for high school students participating in supervised agricultural experience programs (SAEPs) was developed in 1998 by a committee of Texas high school teachers of agriscience and Texas Education Agency personnel. The career portfolio management tool reflects General Accepted Accounting Principles…

  11. Determining Perceptions of Vocational Agriculture Teachers toward Supervised Occupational Experience Programs in Tennessee. Research Report Series No. 9.

    ERIC Educational Resources Information Center

    Lamberth, Edwin E.

    A study investigated perceptions of high school vocational agriculture teachers of supervised occupational experience programs (SOEPs) in Tennessee. Specific objectives were to determine school policies related to SOEPs, number of students and types of SOEPs, and perceptions of various aspects of SOEPs. Mailed surveys were completed by 84 of 214…

  12. Supervised Agricultural Experience Programmes (SAEP) and Work Linked Education (WLE): Panacea for Empowering Youths and Preventing Joblessness

    ERIC Educational Resources Information Center

    Famiwole, Remigius O.

    2015-01-01

    Youths from Nigerian schools and tertiary institutions are usually unemployable after schooling because they are not empowered with the required saleable skills to earn them a job or with which to establish as entrepreneurs. This paper examines the relevance of Supervised Agricultural Experience Programme (SAEP) and Work Linked Education (WLE) as…

  13. Oscillations of a dipole in a magnetic field: An experiment

    NASA Astrophysics Data System (ADS)

    Bisquert, Juan; Hurtado, Emilia; Mafé, Salvador; Pina, José

    1990-09-01

    The small oscillations of a parallelepidal magnet along the axis of a circular coil carrying an electric current have been analyzed theoretically and experimentally. The study of this system (a particular case of a magnetic dipole in motion in a nonuniform magnetic field) involves basic ideas from both mechanics and electromagnetism, and the equipment used in the experiment is very common in an undergraduate laboratory. Comparison with the experiment shows that a very simple theoretical approach gives good results. It is also shown how the introduction of some refinements in the physical model can improve the agreement between theory and experiment, though the theoretical analysis becomes more involved in this case. The use of the principle of superposition to calculate magnetic fields is emphasized throughout the article.

  14. Evaluation of the effects of varying moisture contents on microwave thermal emissions from agriculture fields

    NASA Technical Reports Server (NTRS)

    Burke, H. H. K.

    1980-01-01

    Three tasks related to soil moisture sensing at microwave wavelengths were undertaken: (1) analysis of data at L, X and K sub 21 band wavelengths over bare and vegetated fields from the 1975 NASA sponsored flight experiment over Phoenix, Arizona; (2) modeling of vegetation canopy at microwave wavelengths taking into consideration both absorption and volume scattering effects; and (3) investigation of overall atmospheric effects at microwave wavelengths that can affect soil moisture retrieval. Data for both bare and vegetated fields are found to agree well with theoretical estimates. It is observed that the retrieval of surface and near surface soil moisture information is feasible through multi-spectral and multi-temporal analysis. It is also established that at long wavelengths, which are optimal for surface sensing, atmospheric effects are generally minimal. At shorter wavelengths, which are optimal for atmosheric retrieval, the background surface properties are also established.

  15. Seasonal OVOC fluxes from an agricultural field planted with sugar beet

    NASA Astrophysics Data System (ADS)

    Custer, T. G.; Schade, G. W.

    2005-12-01

    Although agricultural crops are generally not strong isoprenoid emitters, they do emit a variety of other atmospherically significant species collectively known as oxygenated VOCs (OVOCs), such as methanol, acetaldehyde, or various hexenal and hexenol compounds. Many OVOCs have longer atmospheric lifetimes than isoprenoid compounds and can affect the atmosphere's oxidative potential at higher elevations and far from sources. We performed selected OVOC flux measurements for select species above an agricultural field planted with sugar beets ( B. vulgaris) in northern Germany in 2004 to better understand the magnitude and controls over these OVOC emissions. Virtual disjunct eddy covariance was used to measure fluxes beginning immediately following seeding and continuing until past harvest. A commercial PTR-MS provided mixing ratios of methanol (m/z 33), acetaldehyde (m/z 45), acetone (m/z 59), and the sum of the isoprene oxidation products methacrolein and methyl vinyl ketone (m/z 71) while 3D wind velocities were measured using a Gill R3 sonic anemometer. Here, we compare the fluxes of methanol and acetone over the growth cycle of sugar beet to plant development as measured by the leaf area index. Methanol fluxes ranged from approximately -0.05 to 0.15 mg C m-2 h-1 (mixing ratios from ~1 to 15 ppbv) and showed a clear diurnal cycle after the sugar beets established a significant leaf area. Acetone fluxes ranged from approximately -0.2 to 0.2 mg C m-2 h-1 (mixing ratios from ~0.2 to 3 ppb). Higher specific emissions were found during earlier growth stages. Methanol flux correlated strongly with latent heat flux (or alternatively, with canopy conductance derived from the latent heat flux), while acetone flux did not. Acetone flux was small compared to methanol flux and sugar beet is likely not a significant acetone emitter. Weekly measurements of soil OVOC exchange using a flux chamber showed that the soil may have contributed significantly to the overall flux values

  16. Organic particulate emissions from field burning of garden and agriculture residues

    NASA Astrophysics Data System (ADS)

    Gonçalves, Cátia; Evtyugina, Margarita; Alves, Célia; Monteiro, Cristina; Pio, Casimiro; Tomé, Mário

    2011-08-01

    To assess the particulate matter (PM) composition, the smoke from three different agriculture and garden residues, commonly subjected to open field burning in Northern Portugal (potato haulm (A), arable weed vegetation (B) and collard greens stalks/pruned green leafy-twigs (C)) have been sampled into 3 different size fractions (PM 2.5, PM 2.5-10 and PM > 10 ). To replicate another frequent practise of reducing or dispose agriculture/garden debris, residue C was complementarily burned in a metal container with addition of used lubricant oil. The size-segregated aerosol samples were analysed for elemental (EC) and organic (OC) carbon by a thermal-optical transmission technique. The organosoluble OC was fractionated by vacuum flash chromatography and analysed by gas chromatography-mass spectrometry (GC-MS). Burning of residue C produced the highest PM emissions. OC was the dominant carbonaceous component in all aerosol samples, contributing to about 98% of total carbon (TC). The detailed chemical profiles of particulate emissions, including organic tracer compounds, have been assessed. The contribution of phenolics (0.2-39% OC, w/w) and organic acids (1.5-13% OC, w/w) to OC was always predominant over other organic compounds, whose distribution patterns were found to vary from one residue to another. The polyphenols, as the guaiacyl derivatives, were particularly abundant in PM from the residue C burning, but anthropogenic constituents completely superimposed the emission profiles after addition of used lubricant oil. It was shown that the prevailing ambient conditions (such as high humidity) likely contributed to atmospheric processes (e.g. coagulation and hygroscopic growth), which influenced the particle size characteristics of the smoke tracers, shifting their distribution to larger diameters. Since it was shown that the relative contribution of different carbon forms and organic compounds may strongly depend on the size of the particulate matter, the barely

  17. Enhancing the Undergraduate Experience: The Role of a Student Organization for Preservice Agricultural Science Teachers

    ERIC Educational Resources Information Center

    Roberts, T. Grady; Harlin, Julie F.; Murphrey, Theresa P.; Dooley, Kim E.

    2007-01-01

    The purpose of this study was to determine if a need exists to establish an organization specifically for preservice agricultural science teachers and if so, the attributes of such an organization. Selected peer preservice agricultural education programs were examined and focus groups were conducted with preservice and inservice teachers. Results…

  18. Locally Generated Printed Materials in Agriculture: Experience from Uganda and Ghana. Education Research Paper. Report.

    ERIC Educational Resources Information Center

    Carter, Isabel

    The needs of grassroots farmers in Uganda and Ghana for locally developed print materials were examined through a postal survey of nearly 200 organizations and examinations of 75 autonomous farmer groups and 95 organizations sharing agricultural information in both countries. Both printed agricultural information relevant to grassroots farmers and…

  19. Vegetation and soils field research data base: Experiment summaries

    NASA Technical Reports Server (NTRS)

    Biehl, L. L.; Daughtry, C. S. T.; Bauer, M. E.

    1984-01-01

    Understanding of the relationships between the optical, spectral characteristics and important biological-physical parameters of earth-surface features can best be obtained by carefully controlled studies over fields and plots where complete data describing the condition of targets are attainable and where frequent, timely spectral measurement can be obtained. Development of a vegetation and soils field research data base was initiated in 1972 at Purdue University's Laboratory for Applications of Remote Sensing and expanded in the fall of 1974 by NASA as part of LACIE. Since then, over 250,000 truck-mounted and helicopter-borne spectrometer/multiband radiometer observations have been obtained of more than 50 soil series and 20 species of crops, grasses, and trees. These data are supplemented by an extensive set of biophysical and meteorological data acquired during each mission. The field research data form one of the most complete and best-documented data sets acquired for agricultural remote sensing research. Thus, they are well-suited to serve as a data base for research to: (1) quantiatively determine the relationships of spectral and biophysical characteristics of vegetation, (2) define future sensor systems, and (3) develop advanced data analysis techniques.

  20. Long-term impact of precision agriculture on a farmer’s field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Targeting management practices and inputs with precision agriculture has high potential to meet some of the grand challenges of sustainability in the coming century. Although potential is high, few studies have documented long-term effects of precision agriculture on crop production and environmenta...

  1. Intensive field measurements of nitrous oxide emissions from a tropical agricultural soil

    NASA Astrophysics Data System (ADS)

    Crill, P. M.; Keller, M.; Weitz, A.; Grauel, B.; Veldkamp, E.

    2000-03-01

    The amount of nitrous oxide (N2O) continues to increase in the atmosphere. Agricultural use of nitrogen fertilizers in the tropics is thought to be an important source of atmospheric N2O. High frequency, highly precise measurements of the N2O flux were made with an automated system deployed in N fertilized and unfertilized agricultural plots of papaya and corn in Costa Rica for an entire corn crop growth to harvest cycle. N2O fluxes were as high as 64 ng N-N2O cm-2 h-1 from fertilized versus 12 ng N-N2O cm-2 h-1 from unfertilized corn and 28 ng N-N2O cm-2 h-1 from fertilized versus 4.6 ng N-N2O cm-2 h-1 from unfertilized papaya. Fertilized corn released more N2O than fertilized papaya over the 125 days of the crop cycle, 1.83 kg N ha-1 versus 1.37 kg N ha-1. This represents a loss as N2O of 1.1 and 0.9% of the total N applied as ammonium nitrate to the corn and papaya, respectively. As has often been observed, N2O fluxes were highly variable. The fastest rates of emission were associated with fertilization and high soil moisture. A diurnal cycle in the fluxes was not evident probably due to the minimal day/night temperature fluctuations. Each chamber was measured between 509 and 523 times over the course of the experiment. This allows us to evaluate the effect on constructed mean fluxes of lowered sampling frequencies. Sampling each collar about once a day throughout the crop cycle (25% of the data set) could result in a calculated mean flux from any individual chamber that can vary by as much as 20% even though the calculated mean would probably be within 10% of the mean of the complete data set. The uncertainty increases very rapidly at lower sampling frequencies. For example, if only 10% of the data set were used which would be the equivalent of sampling every other day, a very high sampling frequency in terms of manual measurements, the calculated mean flux could vary by as much as 40% or more at any given site.

  2. Estimation of spatially distributed surface energy fluxes using remotely-sensed data for agricultural fields

    NASA Astrophysics Data System (ADS)

    Melesse, Assefa M.; Nangia, Vijay

    2005-09-01

    ). The flux estimation procedure from the SEBAL-TSEB model was useful and applicable to agricultural fields.

  3. Electric field measurements during the Condor critical velocity experiment

    NASA Technical Reports Server (NTRS)

    Kelley, M. C.; Pfaff, R. F.; Haerendel, G.

    1986-01-01

    The instrumentation of the Condor critical velocity Ba experiment (Wescott et al., 1986) for the measurements of the energetic particles and the electric field associated with a Ba explosion is described. The Ba explosion created a complex electric field pulse detected in situ by a single-axis double electric-field probe on a separate spacecraft. The measurements provide evidence of several important links in the critical-velocity chain, and are consistent with two hypotheses. The first hypothesis involves the creation of large polarization electric field due to charge separation; the second hypothesis implies a polarization of the beam by currents flowing across it. The chain of physical processes inferred from the observations is in agreement with most theories for the Alfven process.

  4. Applied magnetic field design for the field reversed configuration compression heating experiment.

    PubMed

    Domonkos, M T; Amdahl, D; Camacho, J F; Coffey, S K; Degnan, J H; Delaney, R; Frese, M; Gale, D; Grabowski, T C; Gribble, R; Intrator, T P; McCullough, J; Montano, N; Robinson, P R; Wurden, G

    2013-04-01

    Detailed calculations of the formation, guide, and mirror applied magnetic fields in the FRC compression-heating experiment (FRCHX) were conducted using a commercially available generalized finite element solver, COMSOL Multiphysics(®). In FRCHX, an applied magnetic field forms, translates, and finally captures the FRC in the liner region sufficiently long to enable compression. Large single turn coils generate the fast magnetic fields necessary for FRC formation. Solenoidal coils produce the magnetic field for translation and capture of the FRC prior to liner implosion. Due to the limited FRC lifetime, liner implosion is initiated before the FRC is injected, and the magnetic flux that diffuses into the liner is compressed. Two-dimensional axisymmetric magnetohydrodynamic simulations using MACH2 were used to specify optimal magnetic field characteristics, and this paper describes the simulations conducted to design magnetic field coils and compression hardware for FRCHX. This paper presents the vacuum solution for the magnetic field. PMID:23635196

  5. The Ecology of Field Experience: Toward an Understanding of the Role of Field Experiences in Teacher Development.

    ERIC Educational Resources Information Center

    Zeichner, Kenneth M.

    1985-01-01

    This paper focuses on conceptual and methodological limitations which have been identified in relation to research on field experiences. A point of view is offered as to how research in this area can begin to provide the kinds of empirical data which will be more useful for policy decisions. (CB)

  6. High Field RMF FRC Experiments on STX-HF

    NASA Astrophysics Data System (ADS)

    Andreason, Samuel; Slough, John

    2001-10-01

    As part of the effort of the TCS program to explore the physics of RMF generated FRCs, a start-up experiment has been constructed to operate at much higher RMF and axial magnetic fields. It is hoped that with the RMF alone at higher power density , it will be possible to form plasmas with both high density, and high electron and ion temperatures. To this end the STX experiment with its 2 MW RMF supply was reconfigured to drive a smaller plasma volume (rp reduced from 18 to 6 cm). In addition an axially remote plasma source was used to supply plasma in a manner that limits neutral contamination and RMF field penetration issues. With axial fields in the kG range, plasma temperatures and densities in a more fusion relevant regime can be studied. Initial results at low RMF power (60 kW) have produced Te = Ti for the first time (T_tot 25 eV). As a result, both ions and electrons are magnetized (ωτ >> 1). Unlike previous experiments, the plasma is formed with a fully penetrated RMF field, producing a rigid rotor current profile. The plasma resistivity at low RMF power is consistent with classical ( 60 μohm-m). The particle confinement is found to be considerably enhanced by the RMF, with a confinement time several times classical. Results at higher power will be presented as well.

  7. A resurrection experiment finds evidence of both reduced genetic diversity and potential adaptive evolution in the agricultural weed Ipomoea purpurea.

    PubMed

    Kuester, Adam; Wilson, Ariana; Chang, Shu-Mei; Baucom, Regina S

    2016-09-01

    Despite the negative economic and ecological impact of weeds, relatively little is known about the evolutionary mechanisms that influence their persistence in agricultural fields. Here, we use a resurrection approach to examine the potential for genotypic and phenotypic evolution in Ipomoea purpurea, an agricultural weed that is resistant to glyphosate, the most widely used herbicide in current-day agriculture. We found striking reductions in allelic diversity between cohorts sampled nine years apart (2003 vs. 2012), suggesting that populations of this species sampled from agricultural fields have experienced genetic bottleneck events that have led to lower neutral genetic diversity. Heterozygosity excess tests indicate that these bottlenecks may have occurred prior to 2003. A greenhouse assay of individuals sampled from the field as seed found that populations of this species, on average, exhibited modest increases in herbicide resistance over time. However, populations differed significantly between sampling years for resistance: some populations maintained high resistance between the sampling years whereas others exhibited increased or decreased resistance. Our results show that populations of this noxious weed, capable of adapting to strong selection imparted by herbicide application, may lose genetic variation as a result of this or other environmental factors. We probably uncovered only modest increases in resistance on average between sampling cohorts due to a strong and previously identified fitness cost of resistance in this species, along with the potential that nonresistant migrants germinate from the seed bank.

  8. A resurrection experiment finds evidence of both reduced genetic diversity and potential adaptive evolution in the agricultural weed Ipomoea purpurea.

    PubMed

    Kuester, Adam; Wilson, Ariana; Chang, Shu-Mei; Baucom, Regina S

    2016-09-01

    Despite the negative economic and ecological impact of weeds, relatively little is known about the evolutionary mechanisms that influence their persistence in agricultural fields. Here, we use a resurrection approach to examine the potential for genotypic and phenotypic evolution in Ipomoea purpurea, an agricultural weed that is resistant to glyphosate, the most widely used herbicide in current-day agriculture. We found striking reductions in allelic diversity between cohorts sampled nine years apart (2003 vs. 2012), suggesting that populations of this species sampled from agricultural fields have experienced genetic bottleneck events that have led to lower neutral genetic diversity. Heterozygosity excess tests indicate that these bottlenecks may have occurred prior to 2003. A greenhouse assay of individuals sampled from the field as seed found that populations of this species, on average, exhibited modest increases in herbicide resistance over time. However, populations differed significantly between sampling years for resistance: some populations maintained high resistance between the sampling years whereas others exhibited increased or decreased resistance. Our results show that populations of this noxious weed, capable of adapting to strong selection imparted by herbicide application, may lose genetic variation as a result of this or other environmental factors. We probably uncovered only modest increases in resistance on average between sampling cohorts due to a strong and previously identified fitness cost of resistance in this species, along with the potential that nonresistant migrants germinate from the seed bank. PMID:27357067

  9. NATO SET-093 joint field experiment at Bourges, France

    NASA Astrophysics Data System (ADS)

    Marty, C.; Bruel, F.; Prieur, D.; Naz, P.; Miller, L. S.

    2009-05-01

    This paper describes the NATO Task Group SET-093/RTG53/MSE (referred to as TG-53 in this report) Acoustic Detection of Weapons Firing Joint Field Experiment II conducted at the Etablissement Technique de Bourges (ETBS), Bourges, France, during 16 to 27 June 2008. This field experiment is a follow-on to the NATO TG-53 Acoustic Detection of Weapons Firing Joint Field Experiment I conducted at the Yuma Proving Grounds (YPG), Yuma, Arizona, USA, during 31 October to 4 November 2005 [1]. The objectives of the joint experiment were: (i) to collect acoustic signatures of direct and indirect firings from weapons' such as small arms, mortars, artillery, rockets, and C4 explosives, (ii) to analyze the propagation effects of grassy, wooded, and urban terrains, (iii) to share signatures collected from a variety of acoustic sensors, on the ground and in the air, distributed over a wide area, and (iv) to demonstrate the interoperability of disparate sensors developed by the various nations involved. The participating NATO countries , including France, the Netherlands, the United Kingdom, Canada, and the United States of America, and Israel as well as part of the Mediterranean dialogue countries, deployed nearly 90 sensors and sensor systems over the test range area.

  10. Soil-plant transfer of Cs-137 and Sr-90 in digestate amended agricultural soils- a lysimeter scale experiment

    NASA Astrophysics Data System (ADS)

    Mehmood, Khalid; Berns, Anne E.; Pütz, Thomas; Burauel, Peter; Vereecken, Harry; Zoriy, Myroslav; Flucht, Reinhold; Opitz, Thorsten; Hofmann, Diana

    2014-05-01

    Radiocesium and radiostrontium are among the most problematic soil contaminants following nuclear fallout due to their long half-lives and high fission yields. Their chemical resemblance to potassium, ammonium and calcium facilitates their plant uptake and thus enhances their chance to reach humans through the food-chain dramatically. The plant uptake of both radionuclides is affected by the type of soil, the amount of organic matter and the concentration of competitive ions. In the present lysimeter scale experiment, soil-plant transfer of Cs-137 and Sr-90 was investigated in an agricultural silty soil amended with digestate, a residue from a biogas plant. The liquid fraction of the digestate, liquor, was used to have higher nutrient competition. Digestate application was done in accordance with the field practice with an application rate of 34 Mg/ha and mixing it in top 5 cm soil, yielding a final concentration of 38 g digestate/Kg soil. The top 5 cm soil of the non-amended reference soil was also submitted to the same mixing procedure to account for the physical disturbance of the top soil layer. Six months after the amendment of the soil, the soil contamination was done with water-soluble chloride salts of both radionuclides, resulting in a contamination density of 66 MBq/m2 for Cs-137 and 18 MBq/m2 for Sr-90 in separate experiments. Our results show that digestate application led to a detectable difference in soil-plant transfer of the investigated radionuclides, effect was more pronounced for Cs-137. A clear difference was observed in plant uptake of different plants. Pest plants displayed higher uptake of both radionuclides compared to wheat. Furthermore, lower activity values were recorded in ears compared to stems for both radionuclides.

  11. Intermittent magnetic field excitations in the Madison Dynamo Experiment

    NASA Astrophysics Data System (ADS)

    Nornberg, M. D.; Spence, E. J.; Jacobson, C. M.; Parada, C. A.; Kendrick, R. D.; Forest, C. B.

    2006-10-01

    Determining the onset conditions for magnetic field growth in magnetohydrodynamics is fundamental to understanding how astrophysical dynamos such as the Earth, the Sun, and the galaxy self-generate magnetic fields. The role of turbulence in modifying these onset conditions is studied in the Madison Dynamo Experiment. A turbulent flow of liquid sodium, composed primarily of two counter-rotating helical vortices, is generated by impellers. Laser Doppler velocimetry measurements of the flow in an identical-scale water experiment demonstrate that the turbulence is isotropic, though not homogeneous, with particularly long-lived eddies in the shear layer between the two flow cells. The magnetic field induced when an axial field is applied shows intermittent periods of growth and has a spatial structure consistent with the fastest growing magnetic eigenmode predicted by a laminar kinematic dynamo model of the mean flow. Turbulent fluctuations of the velocity field change the flow geometry such that the eigenmode growth rate is temporarily positive, thus generating the magnetic bursts. It is found from ensemble averaging that the bursts gain strength and frequency with increased impeller rotation rate, though they become shorter so that each burst remains a rare, random event. Nornberg et al., Phys. Rev. Lett., in press (2006), physics/0606239.

  12. Using a Field Experience to Build Understanding of Planetary Geology

    NASA Astrophysics Data System (ADS)

    Higbie, M.; Treiman, A.; Kiefer, W.; Shipp, S.

    2004-12-01

    In the summer of 2004, the Lunar and Planetary Institute hosted 25 middle- and high-school teachers on a week-long field experience in Idaho and Montana. This workshop mixed field work with classroom experiences and provided educators and scientists the opportunity to interact. The educators investigated deposits associated with Glacial Lake Missoula floods and lava flows in the Craters of the Moon National Monument and Preserve. The participants applied what they learned about Earth-based processes to develop understanding of processes operating on Mars and the most recent results from NASA's missions to Mars. This was the most recent of five field-based experiences that used Earth-planet comparisons as a basis for experiential learning. These field experiences all are designed to strengthen content knowledge of geologic processes and planetary sciences. Learning geology through fieldwork enables participants to take ownership of the content through real-life experience; in essence, the teacher becomes the student. Establishing deeper knowledge of the content increases their confidence in facilitating inquiry-based science in their own classrooms. In addition to content, the educators are immersed in the process of science. Participants make observations, compile notes and illustrations, debate interpretations, draw conclusions, and communicate findings. Care was taken to separate observations and interpretations to help build an understanding of scientific reasoning. Discussions often involved questions without solutions, or with multiple solutions. While some participants expressed discomfort with these aspects of the nature of science, most were more comfortable with open-ended, inquiry based exploration by the close of the workshop. The field work is coupled with discussion and activities in the classroom. Participants reflected on the field sites and placed them in the context of the geologic history of the region. Observations and interpretations at

  13. Active experiments in the ionosphere and geomagnetic field variations

    NASA Astrophysics Data System (ADS)

    Sivokon, V. P.; Cherneva, N. V.; Khomutov, S. Y.; Serovetnikov, A. S.

    2014-11-01

    Variations of ionospheric-magnetospheric relation energy, as one of the possible outer climatology factors, may be traced on the basis of analysis of natural geophysical phenomena such as ionosphere artificial radio radiation and magnetic storms. Experiments on active impact on the ionosphere have been carried out for quite a long time in Russia as well. The most modern heating stand is located in Alaska; it has been used within the HAARP Program. The possibility of this stand to affect geophysical fields, in particular, the geomagnetic field is of interest.

  14. Laboratory and Field Experiments on Expulsion of Selected Ions along Divergent Polar Geomagnetic Fields

    NASA Astrophysics Data System (ADS)

    Wong, A. Y.; Deng, B.; Quon, B.; Wang, R.; Hartzell, J.; Rosenthal, G.; Hazelton, L. R.

    2007-12-01

    Laboratory and Field Experiments on Expulsion of Selected Ions along Divergent Polar Geomagnetic Fields. Laboratory experiments have shown significant gyro-resonance acceleration of minority ion species in a magnetized plasma. Field aligned elctron drifts can provide free energy needed to make this process efficient. The linear magnetized device has a uniform magnetic field linked to two adjustable mirrors at the ends. Outdoor experiments at HIPAS Facility Ak(1) ( 84 MW ERP ) are used to test this process in the earth's "chimneys" at the two poles. The divergent polar geomagnetic field converts the perpendicular ion velocity into an upward motion. Satellites and ground-based ELF receivers,supplemented by UHF radars, LIDARs and infrared diagnostics , will monitor low-frequency EM waves and upflows of ions. The upward transport of ions in the lower atmosphere by field-induced diffusion and convection and the coupling to the free energy in the auroral region will be discussed. Computer modeling and theoeries complement our experiments. 1. Wong, A.Y. et al. AIP CIP 96-27719, Chap 3, pp 41-75, 1997

  15. Changes in water budgets and sediment yields from a hypothetical agricultural field as a function of landscape and management characteristics--A unit field modeling approach

    USGS Publications Warehouse

    Roth, Jason L.; Capel, Paul D.

    2012-01-01

    Crop agriculture occupies 13 percent of the conterminous United States. Agricultural management practices, such as crop and tillage types, affect the hydrologic flow paths through the landscape. Some agricultural practices, such as drainage and irrigation, create entirely new hydrologic flow paths upon the landscapes where they are implemented. These hydrologic changes can affect the magnitude and partitioning of water budgets and sediment erosion. Given the wide degree of variability amongst agricultural settings, changes in the magnitudes of hydrologic flow paths and sediment erosion induced by agricultural management practices commonly are difficult to characterize, quantify, and compare using only field observations. The Water Erosion Prediction Project (WEPP) model was used to simulate two landscape characteristics (slope and soil texture) and three agricultural management practices (land cover/crop type, tillage type, and selected agricultural land management practices) to evaluate their effects on the water budgets of and sediment yield from agricultural lands. An array of sixty-eight 60-year simulations were run, each representing a distinct natural or agricultural scenario with various slopes, soil textures, crop or land cover types, tillage types, and select agricultural management practices on an isolated 16.2-hectare field. Simulations were made to represent two common agricultural climate regimes: arid with sprinkler irrigation and humid. These climate regimes were constructed with actual climate and irrigation data. The results of these simulations demonstrate the magnitudes of potential changes in water budgets and sediment yields from lands as a result of landscape characteristics and agricultural practices adopted on them. These simulations showed that variations in landscape characteristics, such as slope and soil type, had appreciable effects on water budgets and sediment yields. As slopes increased, sediment yields increased in both the arid and

  16. Effects of microelements on soil nematode assemblages seven years after contaminating an agricultural field.

    PubMed

    Nagy, Péter; Bakonyi, Gábor; Bongers, Tom; Kádár, Imre; Fábián, Miklós; Kiss, István

    2004-03-29

    Long-term effects of Cd, Cr, Cu, Se and Zn were studied 7 years after artificially contaminating plots of an agricultural field on a calcareous chernozem soil. Effects of three to four different contamination levels (originally 10, 30, 90 and 270 mg kg(-1)) were studied. Nematode density was significantly reduced by 90 and 270 mg kg(-1) Se as well as by 270 mg kg(-1) Cr, while 90 and 270 mg kg(-1) Se also reduced nematode generic richness. Maturity Index values (calculated for c-p 2-5 nematodes) consistently decreased with increasing Cr and Se concentration and to a lesser extent in Zn plots as well. Structure Index showed decreasing trends in increasing Cr, Se and (to a lesser extent) in Zn treatments, while in Cd it shows a moderate increase. Distribution of c-p groups was negatively affected by the increasing Cr and Se concentration, while in Zn plots, this decrease was not significant. Response of feeding groups to pollutions was similar to other parameters: Cr and Se caused significant changes toward the loss of variability. The proportion of the most sensitive omnivorous and predatory nematodes decreased clearly as a consequence of Cr and Se treatments. Zn pollution also resulted in a slight decrease in this group, while Cd caused an increase. Nematode diversity profiles showed a significant decrease in the plots of increased Cr and Se concentrations, while increased concentrations of Cu and Zn resulted in ambiguous effects. Besides providing evidence on the harmful effects of Cr and Se on a soil nematode assemblage, our results suggest that simultaneous analysis of Maturity Index, Structure Index and diversity profiles provide a promising tool in nematological indication of soil pollution.

  17. ITER Test Blanket Module Error Field Simulation Experiments

    NASA Astrophysics Data System (ADS)

    Schaffer, M. J.

    2010-11-01

    Recent experiments at DIII-D used an active-coil mock-up to investigate effects of magnetic error fields similar to those expected from two ferromagnetic Test Blanket Modules (TBMs) in one ITER equatorial port. The largest and most prevalent observed effect was plasma toroidal rotation slowing across the entire radial profile, up to 60% in H-mode when the mock-up local ripple at the plasma was ˜4 times the local ripple expected in front of ITER TBMs. Analysis showed the slowing to be consistent with non-resonant braking by the mock-up field. There was no evidence of strong electromagnetic braking by resonant harmonics. These results are consistent with the near absence of resonant helical harmonics in the TBM field. Global particle and energy confinement in H-mode decreased by <20% for the maximum mock-up ripple, but <5% at the local ripple expected in ITER. These confinement reductions may be linked with the large velocity reductions. TBM field effects were small in L-mode but increased with plasma beta. The L-H power threshold was unaffected within error bars. The mock-up field increased plasma sensitivity to mode locking by a known n=1 test field (n = toroidal harmonic number). In H-mode the increased locking sensitivity was from TBM torque slowing plasma rotation. At low beta, locked mode tolerance was fully recovered by re-optimizing the conventional DIII-D ``I-coils'' empirical compensation of n=1 errors in the presence of the TBM mock-up field. Empirical error compensation in H-mode should be addressed in future experiments. Global loss of injected neutral beam fast ions was within error bars, but 1 MeV fusion triton loss may have increased. The many DIII-D mock-up results provide important benchmarks for models needed to predict effects of TBMs in ITER.

  18. Soil apparent conductivity measurements for planning and analysis of agricultural experiments: A case study from Western-Thailand

    NASA Astrophysics Data System (ADS)

    Rudolph, Sebastian; Wongleecharoen, Chalermchart; Lark, Richard Murray; Marchant, Ben Paul; Garré, Sarah; Herbst, Michael; Vereecken, Harry; Weihermueller, Lutz

    2016-04-01

    In agricultural experiments the success or failure of a potential improvement is generally evaluated based on the plant response, using proper experimental designs with sufficient statistical power. Because within-site variability can negatively affect statistical power, improvements in the experimental design can be achieved if this variation is well understood and incorporated into the experimental design, or if some surrogate variable is used as a covariate in the analysis. Apparent soil electrical conductivity (ECa), measured by electromagnetic induction (EMI) may be one source of this information. The objective of this study was to investigate the effectiveness of EMI-derived ECa measurements for planning and analysis of agricultural experiments. ECa and plant height measurements of maize (the response variable) were taken from an agricultural experiment in Western Thailand. A statistical model of these variables was used to simulate experiments with different designs and treatment effects. The simulated data were used to quantify the statistical power when testing three orthogonal contrasts. The following experimental designs were considered: a simple random design (SR), a complete randomized block design (CRB), and a complete randomized block design with spatially adjusted blocks on plot means of ECa (CRBECa). According to an analysis of variance (ANOVA) the smallest effect sizes could be detected using the CRBECa design, which suggests that ECa survey measurements could be used in the planning phase of an experiment to achieve efficiencies by better blocking. Also, analysis of covariance (ANCOVA) showed that larger power improvements could be achieved when ECa was used as a covariate in the analysis. We therefore recommend that ECa measurements should be used to describe subsurface variability and to support the statistical analysis of agricultural experiments.

  19. Fields of dreams: Agriculture, economy and nature in Midwest United States biofuel production

    NASA Astrophysics Data System (ADS)

    Gillon, Sean Thomas

    This work explores the social and ecological dimensions of recent biofuel production increases in the United States (US), focusing on the case of Iowa. Biofuels are proposed to mitigate the greenhouse gas emissions that cause climate change, improve US energy security, and support rural economies. Little research has examined how increased US Midwestern biofuels production will change social and ecological outcomes at farm and regional levels or interact with broader governance processes at the nexus of agriculture, energy and environment. These broad questions guide my research: (1) How does biofuel production reconfigure agricultural practice and landscapes in Iowa? (2) What are the costs, benefits and risks of increased biofuels production as seen by farmers and rural residents, and how do these factors influence farmer decisions about agriculture and conservation practice? (3) How and with what effects are biofuels initiatives constituted as a form of environmental governance through scientific knowledge and practice and political economic dynamics? To address these questions, this research integrates both qualitative and quantitative methods, drawing on a political ecological approach complemented by agroecological analysis and theoretical insights from geographical analyses of nature-society relations. Quantitative analysis focuses on changing land use patterns in agriculture and conservation practice in Iowa. Qualitative methods include extensive interviews, participant observation, and policy and document analyses. Fieldwork focused on Northeastern Iowa to understand regional changes in agricultural and conservation practice, the renegotiated position of farmers in agriculture and biofuel production, and biofuel industry development. I find that biofuel production presents significant social and ecological challenges for rural places of production. Longstanding, unequal political economic relations in industrialized agriculture limit rural economic benefits

  20. Acoustic experience shapes female mate choice in field crickets

    PubMed Central

    Bailey, Nathan W; Zuk, Marlene

    2008-01-01

    Female choice can drive the evolution of extravagant male traits. In invertebrates, the influence of prior social experience on female choice has only recently been considered. To better understand the evolutionary implications of experience-mediated plasticity in female choice, we investigated the effect of acoustic experience during rearing on female responsiveness to male song in the field cricket Teleogryllus oceanicus. Acoustic experience has unique biological relevance in this species: a morphological mutation has rendered over 90 per cent of males on the Hawaiian island of Kauai silent in fewer than 20 generations, impeding females' abilities to locate potential mates. Females reared in silent conditions mimicking Kauai were less discriminating of male calling song and more responsive to playbacks, compared with females that experienced song during rearing. Our results to our knowledge, are the first demonstration of long-term effects of acoustic experience in an arthropod, and suggest that female T. oceanicus may be able to compensate for the reduced availability of long-range male sexual signals by increasing their responsiveness to the few remaining signallers. Understanding the adaptive significance of experience-mediated plasticity in female choice provides insight into processes that facilitate rapid evolutionary change and shape sexual selection pressure in natural populations. PMID:18700205

  1. An Integral, Multidisciplinary and Global Geophysical Field Experience for Undergraduates

    NASA Astrophysics Data System (ADS)

    Vázquez, O.; Carrillo, D. J.; Pérez-Campos, X.

    2007-05-01

    The udergraduate program of Geophysical Engineering at the School of Engineering, of the Univesidad Nacional Autónoma de México (UNAM), went through an update process that concluded in 2006. As part of the program, the student takes three geophysical prospecting courses (gravity and magnetics, electric, electromagnetics, and seismic methods). The older program required a three-week field experience for each course in order to gradute. The new program considers only one extended field experience. This work stresses the importance of international academic exchange, where undergraduate students could participate, such as the Summer of Applied Geophysical Experience (SAGE), and interaction with research programs, such as the MesoAmerican Subduction Experiment (MASE). Also, we propose a scheeme for this activity based on those examples; both of them have in common real geophysical problems, from which students could benefit. Our proposal covers academic and logistic aspects to be taken into account, enhancing the relevance of interaction between other academic institutions, industry, and UNAM, in order to obtain a broader view of geophysics.

  2. Dark matter effective field theory scattering in direct detection experiments

    SciTech Connect

    Schneck, K.

    2015-05-01

    We examine the consequences of the effective field theory (EFT) of dark matter–nucleon scattering for current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. We demonstrate that spectral differences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. We also discuss the implications of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.

  3. Dark matter effective field theory scattering in direct detection experiments

    DOE PAGES

    Schneck, K.

    2015-05-01

    We examine the consequences of the effective field theory (EFT) of dark matter–nucleon scattering for current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. We demonstrate that spectral differences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. We also discuss the implicationsmore » of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.« less

  4. Dark matter effective field theory scattering in direct detection experiments

    NASA Astrophysics Data System (ADS)

    Schneck, K.; Cabrera, B.; Cerdeño, D. G.; Mandic, V.; Rogers, H. E.; Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.; Barker, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.; Borgland, A.; Brandt, D.; Brink, P. L.; Bunker, R.; Caldwell, D. O.; Calkins, R.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.; Hall, J.; Harris, H. R.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jardin, D. M.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Leder, A.; Loer, B.; Lopez Asamar, E.; Lukens, P.; Mahapatra, R.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt, R. A.; Morales Mendoza, J. D.; Oser, S. M.; Page, K.; Page, W. A.; Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Roberts, A.; Saab, T.; Sadoulet, B.; Sander, J.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.; Speller, D.; Toback, D.; Upadhyayula, S.; Villano, A. N.; Welliver, B.; Wilson, J. S.; Wright, D. H.; Yang, X.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.; SuperCDMS Collaboration

    2015-05-01

    We examine the consequences of the effective field theory (EFT) of dark matter-nucleon scattering for current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. We demonstrate that spectral differences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. We also discuss the implications of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.

  5. Dark matter effective field theory scattering in direct detection experiments

    SciTech Connect

    Schneck, K.; Cabrera, B.; Cerdeño, D. G.; Mandic, V.; Rogers, H. E.; Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.; Barker, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.; Borgland, A.; Brandt, D.; Brink, P. L.; Bunker, R.; Caldwell, D. O.; Calkins, R.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.; Hall, J.; Harris, H. R.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jardin, D. M.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Leder, A.; Loer, B.; Lopez Asamar, E.; Lukens, P.; Mahapatra, R.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt, R. A.; Morales Mendoza, J. D.; Oser, S. M.; Page, K.; Page, W. A.; Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Roberts, A.; Saab, T.; Sadoulet, B.; Sander, J.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.; Speller, D.; Toback, D.; Upadhyayula, S.; Villano, A. N.; Welliver, B.; Wilson, J. S.; Wright, D. H.; Yang, X.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.

    2015-05-18

    We examine the consequences of the effective field theory (EFT) of dark matter-nucleon scattering for current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. Here. we demonstrate that spectral differences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. In conclusion, we discuss the implications of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.

  6. Developing Programs of Supervised Agricultural Experience. Developing an SAE Program Using the Missouri Agricultural Record Book for Secondary Students. Analyzing the SAE Program Using the Missouri Farm Business Record Book. Instructor's Guide. Volume 21, Number 9.

    ERIC Educational Resources Information Center

    Admire, Myron

    This curriculum guide to the Supervised Agricultural Experience (SAE) program contains four units of insturctor's materials as follows: Unit 1: Developing an SAE Program; Unit 2: Using the Missouri Agricultural Record Book for Secondary Students; Unit 3: Analyzing the SAE Program; and Unit 4: Using the Missouri Farm Business Record Book. The…

  7. Inverse Simulation of Field Infiltration Experiment Counting Preferential Flow

    NASA Astrophysics Data System (ADS)

    Zumr, David; Snehota, Michal; Nemcova, Renata; Dohnal, Michal; Cislerova, Milena

    2010-05-01

    The field tension and ponded infiltration experiments were conducted to monitor and describe irregularities of moisture propagation and to estimate the soil hydraulic properties (Distric Cambisol, Korkusova Hut, Sumava). On these soils the preferential pathways have been observed in several scales with the use of dye tracers, MRI and CT imaging. Preferential behavior was detected also during laboratory infiltration experiments. The flow irregularities are credited to variable air entrapment at the beginning of infiltrations. The field infiltration experiment was carried out in a shallow pit for a period of one day. The upper boundary condition was controlled by the tension disk infiltrometer, the propagation of a water front was monitored by two tensiometers installed in two depths below the infiltration disk. The propagation of saline solution front during ponded infiltration was visualized with high resolution electrical resistivity tomography (ERT). Infiltration experiments were monitored with TDR probes, tensiometers and ERT. Zones of preferential flow were determined through analyses of photographs taken during laboratory dye tracer infiltration experiments performed on undisturbed soil samples. Connectivity, volumetric ratio and spatial development of preferential pathways were evaluated as the necessary information for numerical simulations of flow using dual-permeability approach. 2D axisymetric numerical simulations were conducted to evaluate the results of the experiment. The parameter estimator PEST coupled with the simulation code S2D_DUAL (Vogel et al., 2000) were employed. Two different approaches were used: 1. Single-domain approach based on Richards' equation. 2. Dual-permeability approach based on two interacting water flow domains (matrix and preferential domains), each governed by one Richards' equation. Concerning the existence of preferential flow on investigated soil, the dual-permeability model gives a better picture of the flow regime. The

  8. Agricultural Waste.

    PubMed

    Xue, Ling; Zhang, Panpan; Shu, Huajie; Chang, Chein-Chi; Wang, Renqing; Zhang, Shuping

    2016-10-01

    In recent years, the quantity of agricultural waste has been rising rapidly all over the world. As a result, the environmental problems and negative impacts of agricultural waste are drawn more and more attention. Therefore, there is a need to adopt proper approaches to reduce and reuse agricultural waste. This review presented about 200 literatures published in 2015 relating to the topic of agricultural waste. The review examined research on agricultural waste in 2015 from the following four aspects: the characterization, reuse, treatment, and management. Researchers highlighted the importance to reuse agricultural waste and investigated the potential to utilize it as biofertilizers, cultivation material, soil amendments, adsorbent, material, energy recycling, enzyme and catalyst etc. The treatment of agricultural waste included carbonization, biodegradation, composting hydrolysis and pyrolysis. Moreover, this review analyzed the differences of the research progress in 2015 from 2014. It may help to reveal the new findings and new trends in this field in 2015 comparing to 2014. PMID:27620093

  9. Agricultural Waste.

    PubMed

    Xue, Ling; Zhang, Panpan; Shu, Huajie; Chang, Chein-Chi; Wang, Renqing; Zhang, Shuping

    2016-10-01

    In recent years, the quantity of agricultural waste has been rising rapidly all over the world. As a result, the environmental problems and negative impacts of agricultural waste are drawn more and more attention. Therefore, there is a need to adopt proper approaches to reduce and reuse agricultural waste. This review presented about 200 literatures published in 2015 relating to the topic of agricultural waste. The review examined research on agricultural waste in 2015 from the following four aspects: the characterization, reuse, treatment, and management. Researchers highlighted the importance to reuse agricultural waste and investigated the potential to utilize it as biofertilizers, cultivation material, soil amendments, adsorbent, material, energy recycling, enzyme and catalyst etc. The treatment of agricultural waste included carbonization, biodegradation, composting hydrolysis and pyrolysis. Moreover, this review analyzed the differences of the research progress in 2015 from 2014. It may help to reveal the new findings and new trends in this field in 2015 comparing to 2014.

  10. Mitigation of dimethazone residues in soil and runoff water from agricultural field.

    PubMed

    Antonious, George F

    2011-01-01

    Dimethazone, also known as clomazone [2-[(2-chlorophenyl) methyl]- 4,4-dimethyl-3-isoxaolidinone] is a pre-emergent nonionic herbicide commonly used in agriculture. A field study was conducted on a silty-loam soil of 10 % slope to monitor off-site movement and persistence of dimethazone in soil under three management practices. Eighteen plots of 22 x 3.7 m each were separated using stainless steel metal borders and the soil in six plots was mixed with municipal sewage sludge (MSS) and yard waste (YW) compost (MSS+YW) at 15 t acre⁻¹ on dry weight basis, six plots were mixed with MSS at 15 t acre⁻¹, and six unamended plots (NM) were used for comparison purposes. The objectives of this investigation were to: (i) monitor the dissipation and half-life (T₁/₂) of dimethazone in soil under three management practices; (ii) determine the concentration of dimethazone residues in runoff and infiltration water following natural rainfall events; and (iii) assess the impact of soil amendments on the transport of NO₃, NH₄, and P into surface and subsurface water. Gas chromatography/mass spectrometery (GC/MS) analyses of soil extracts indicated the presence of ion fragments at m/z 125 and 204 that can be used for identification of dimethazone residues. Intitial deposits of dimethazone varied from 1.3 μg g⁻¹ dry native soil to 3.2 and 11.8 μg g⁻¹ dry soil in MSS and MSS+YW amended soil, respectively. Decline of dimethazone residues in the top 15 cm native soil and soil incorporated with amendments revealed half-life (T₁/₂) values of 18.8, 25.1, and 43.0 days in MSS+YW, MSS, and NM treatments, respectively. Addition of MSS+YW mix and MSS alone to native soil increased water infiltration, lowering surface runoff water volume and dimethazone residues in runoff following natural rainfall events.

  11. Environmental Fate of the Herbicide Fluazifop-P-butyl and Its Degradation Products in Two Loamy Agricultural Soils: A Combined Laboratory and Field Study.

    PubMed

    Badawi, Nora; Rosenbom, Annette E; Olsen, Preben; Sørensen, Sebastian R

    2015-08-01

    The herbicide fluazifop-P-butyl (FPB) is used against grasses in agricultural crops such as potato, oilseed rape, and sugar beet. Limited information is available in scientific literature on its environmental fate, therefore extensive monitoring at two agricultural test fields was combined with laboratory studies to determine leaching and the underlying degradation and sorption processes. Water samples from drains, suction cups, and groundwater wells showed leaching of the degradation products fluazifop-P (FP) and 2-hydroxy-5-trifluoromethyl-pyridin (TFMP) following FPB treatment. Laboratory experiments with soil from each field revealed a rapid degradation of FPB to FP. The degradation was almost exclusively microbial, and further biodegradation to TFMP occurred at a slower rate. Both degradation products were sorbed to the two soils to a small extent and were fairly persistent to degradation during the two-month incubation period. Together, the field and laboratory results from this study showed that the biodegradation of FPB in loamy soils gave rise to the production of two major degradation products that sorbed to a small extent. In this study, both degradation products leached to drainage and groundwater during precipitation. It is therefore recommended that these degradation products be included in programs monitoring water quality in areas with FPB use.

  12. Massless scalar field and solar-system experiments

    SciTech Connect

    Formiga, J. B.

    2011-04-15

    The solution of Einstein's field equations with the energy-momentum tensor of a massless scalar field is known as the Fisher solution. It is well known that this solution has a naked singularity due to the ''charge''{Sigma} of the massless scalar field. Here I obtain the radial null geodesic of the Fisher solution and use it to confirm that there is no black hole. In addition, I use the parametrized post-Newtonian formalism to show that the Fisher spacetime predicts the same effects on solar-system experiments as the Schwarzschild one does, as long as we impose a limit on {Sigma}. I show that this limit is not a strong constraint and we can even take values of {Sigma} bigger than M. By using the exact formula of the redshift and some assumptions, I evaluate this limit for the experiment of Pound and Snider [Phys. Rev. 140, B788 (1965)]. It turns out that this limit is {Sigma}<5.8x10{sup 3} m.

  13. The TCS Rotating Magnetic Field FRC Current-Drive Experiment

    SciTech Connect

    Hoffman, Alan J.; Guo, Houyang Y.; Slough, John T.; Tobin, Stephen J.; Schrank, Louis S.; Reass, William A.; Wurden, Glen A.

    2002-03-15

    Field-reversed configurations (FRCs) have extremely attractive reactor attributes because of their singly connected geometry. They have been created in theta-pinch devices, but being compact toroids and lacking a center hole, their toroidal current cannot be sustained by transformer action as in other toroidal configurations. A new device, the Translation, Confinement, and Sustainment (TCS) facility has been constructed to use rotating magnetic fields (RMFs) to build up and sustain the flux of hot FRCs formed by the normal theta-pinch method. RMF formation and sustainment of similar, but cold, pure poloidal field configurations have been demonstrated in devices called rotamaks, and RMF formation, but not sustainment, has been achieved in a smaller FRC facility called the Star Thrust Experiment (STX). Initial formation and sustainment have now been achieved in TCS, albeit still with cold (T{sub e} {approx} 50 eV) plasmas. Both the formation and final steady-state conditions are found to agree with newly developed analytic and numerical models for RMF flux buildup and sustainment inside a standard cylindrical flux conserver. The required plasma conditions (mainly resistivity but also density) can now be determined for the planned hot FRC, RMF flux buildup experiments and for eventual reactor conditions.

  14. Embrapa's experience in the production and development of agriculture reference materials

    NASA Astrophysics Data System (ADS)

    Nogueira, A. R. A.; Souza, G. B.; Bossu, C. M.; Bianchi, S. R.; Verhalen, T. R.; Silva, P. T.; Peixoto, A. A. J.; Silva, C. S.

    2016-07-01

    The main challenge of Embrapa is to develop a model of genuine Brazilian tropical agriculture and livestock. To get this task, the quality of laboratories results is mandatory, increasing the demand for reference materials. Projects were proposed to produce reference materials to support the national agriculture laboratories and consolidate a network able to perform reliable and reproducible analytical testing laboratory within the internationally standards required. Reference materials were produced and available to interested laboratories and collaborative tests were conducted to obtain consensus values. The results and statistical evaluations were performed with the use of software developed by Embrapa Pecuaria Sudeste.

  15. Agricultural application of SWECS

    NASA Astrophysics Data System (ADS)

    Nelson, V.

    Principal applications of wind energy for agriculture are (1) farmstead power, mainly electrical, (2) building heating, (3) irrigation pumping, (4) product storage and processing, (5) hot water for residences and dairies, and (6) associated industries of agribusiness such as feedlots, fertilizer elevators, greenhouses, etc. Field experiments show that wind energy is a viable alternative, however, reliability and maintenance are still major problems. Test results of the various experiments are described.

  16. Large scale meteorological influence during the Geysers 1979 field experiment

    SciTech Connect

    Barr, S.

    1980-01-01

    A series of meteorological field measurements conducted during July 1979 near Cobb Mountain in Northern California reveals evidence of several scales of atmospheric circulation consistent with the climatic pattern of the area. The scales of influence are reflected in the structure of wind and temperature in vertically stratified layers at a given observation site. Large scale synoptic gradient flow dominates the wind field above about twice the height of the topographic ridge. Below that there is a mixture of effects with evidence of a diurnal sea breeze influence and a sublayer of katabatic winds. The July observations demonstrate that weak migratory circulations in the large scale synoptic meteorological pattern have a significant influence on the day-to-day gradient winds and must be accounted for in planning meteorological programs including tracer experiments.

  17. Equilibrium evolution in oscillating-field current-drive experiments

    NASA Astrophysics Data System (ADS)

    McCollam, K. J.; Anderson, J. K.; Blair, A. P.; Craig, D.; Den Hartog, D. J.; Ebrahimi, F.; O'Connell, R.; Reusch, J. A.; Sarff, J. S.; Stephens, H. D.; Stone, D. R.; Brower, D. L.; Deng, B. H.; Ding, W. X.

    2010-08-01

    Oscillating-field current drive (OFCD) is a proposed method of steady-state toroidal plasma sustainment in which ac poloidal and toroidal loop voltages are applied to produce a dc plasma current. OFCD is added to standard, inductively sustained reversed-field pinch plasmas in the Madison Symmetric Torus [R. N. Dexter et al., Fusion Technol. 19, 131 (1991)]. Equilibrium profiles and fluctuations during a single cycle are measured and analyzed for different relative phases between the two OFCD voltages and for OFCD off. For OFCD phases leading to the most added plasma current, the measured energy confinement is slightly better than that for OFCD off. By contrast, the phase of the maximum OFCD helicity-injection rate also has the maximum decay rate, which is ascribed to transport losses during discrete magnetic-fluctuation events induced by OFCD. Resistive-magnetohydrodynamic simulations of the experiments reproduce the observed phase dependence of the added current.

  18. SRNL RADIONUCLIDE FIELD LYSIMETER EXPERIMENT: BASELINE CONSTRUCTION AND IMPLEMENTATION

    SciTech Connect

    Roberts, K.; Kaplan, D.; Bagwell, L.; Powell, B.; Almond, P.; Emerson, H.; Hixon, A.; Jablonski, J.; Buchanan, C.; Waterhouse, T.

    2012-10-17

    The purpose of this document is to compile information regarding experimental design, facility design, construction, radionuclide source preparation, and path forward for the ten year Savannah River National Laboratory (SRNL) Radionuclide Field Lysimeter Experiment at the Savannah River Site (SRS). This is a collaborative effort by researchers at SRNL and Clemson University. The scientific objectives of this study are to: Study long-term radionuclide transport under conditions more representative of vadose zone conditions than laboratory experiments; Provide more realistic quantification of radionuclide transport and geochemistry in the vadose zone, providing better information pertinent to radioactive waste storage solutions than presently exists; Reduce uncertainty and improve justification for geochemical models such as those used in performance assessments and composite analyses.

  19. Experiments of cylindrical isentropic compression by ultrahigh magnetic field

    NASA Astrophysics Data System (ADS)

    Gu, Zhuowei; Zhou, Zhongyu; Zhang, Chunbo; Tang, Xiaosong; Tong, Yanjin; Zhao, Jianheng; Sun, Chengwei

    2015-09-01

    The high Explosive Magnetic Flux Implosion Compression Generator (EMFICG) is a kind of unique high energy density dynamic technique with characters like ultrahigh pressure and low temperature rising and could be suitable as a tool of cylindrical isentropic compression. The Institute of Fluid Physics, Chinese Academy of Engineering Physics (IFP, CAEP) have developed EMFICG technique and realized cylindrical isentropic compression. In the experiments, a seed magnetic field of 5-6 Tesla were built first and compressed by a stainless steel liner which is driven by high explosive. The inner free surface velocity of sample was measured by PDV. The isentropic compression of a copper sample was verified and the isentropic pressure is over 100 GPa. The cylindrical isentropic compression process has been numerical simulated by 1D MHD code and the simulation results were compared with the experiments. Compared with the transitional X-ray flash radiograph measurement, this method will probably promote the data accuracy.

  20. ASCOT 91 field experiment : PNL airsonde data summary.

    SciTech Connect

    JM Hubbe and KJ Allwine

    1991-07-01

    Pacific Northwest Laboratory (PNL) participated in the Winter 1991 Atmospheric Studies in Complex Terrain (ASCOT) field experiment conducted in the vicinity of the Rocky Flats Plant between Boulder and Denver, Colorado. This report contains a summary of operations and data associated with free-release-ball oon-borne atmospheric soundings made by PNL between January 29 and February 8, 1991. Given here are descriptions of the site and instrumentation, a brief summary of the soundings, and a description of the data post processing. The appendices contain a detailed summary of all soundings and ASCOT plots of completed soundings.

  1. Radiative transfer model validations during the First ISLSCP Field Experiment

    NASA Technical Reports Server (NTRS)

    Frouin, Robert; Breon, Francois-Marie; Gautier, Catherine

    1990-01-01

    Two simple radiative transfer models, the 5S model based on Tanre et al. (1985, 1986) and the wide-band model of Morcrette (1984) are validated by comparing their outputs with results obtained during the First ISLSCP Field Experiment on concomitant radiosonde, aerosol turbidity, and radiation measurements and sky photographs. Results showed that the 5S model overestimates the short-wave irradiance by 13.2 W/sq m, whereas the Morcrette model underestimated the long-wave irradiance by 7.4 W/sq m.

  2. Cartoon music in a candy store: a field experiment.

    PubMed

    Le Guellec, Hélène; Guéguen, Nicolas; Jacob, Céline; Pascual, Alexandre

    2007-06-01

    An experiment on consumers' behavior was carried out in a new field context. According to a random assignment, 60 customers from ages 12 to 14 years who entered a candy store were exposed to Top Forty music which was usually played in this store, music from cartoons (Captain Flame, Candy, Olive & Tom, etc.), or no music. Analysis showed that customers spent significantly more time in the store when cartoon music was played, but the two styles of music were not related to the amount of money spent.

  3. An Evaluation of a Welding Fumes Exhaust System. Agricultural Experiment Station Research Report 284.

    ERIC Educational Resources Information Center

    Jacobs, C. O.

    A study evaluated the feasibility of introducing unheated outside air into the airstream of a cross-flow welding exhaust system to reduce heating energy costs of a school welding laboratory. The physical facility used was the agricultural mechanics laboratory at the University of Arizona, which is similar to facilities in which instruction in…

  4. Perceptions of Teaching Ability during the Student Teaching Experience in Agricultural Education

    ERIC Educational Resources Information Center

    Krysher, Sheyenne; Robinson, J. Shane; Montgomery, Diane; Edwards, M. Craig

    2012-01-01

    The purpose of this study was to describe the views student teachers in agricultural education at Oklahoma State University had regarding their 12-week student teaching internship. Using Q-methodology as a research approach, 28 interns rank-ordered a Q-set of 36 statements describing various aspects teacher responsibilities and performance. The…

  5. Changing Horses: Shifting Agricultural Experiment Station Publications from Paper to Electronic Format.

    ERIC Educational Resources Information Center

    Rhodenbaugh, Eric; Holcombe, Gloria; Hartman, Amy

    2003-01-01

    The Agricultural Experimental Station at Kansas State University switched from paper publication to compact discs. The change resulted in savings of more than $20,000 in 1 year and allowed for a searchable, comprehensive package of information rather than a single publication. (Contains 10 references.) (JOW)

  6. VOCATIONAL AGRICULTURE.

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento. Research Coordinating Unit.

    TO ASSIST THOSE WHO MAKE DECISIONS RELATING TO EDUCATIONAL PROGRAMS IN AGRICULTURE, RECENT RESEARCH IN VOCATIONAL AGRICULTURE IS SUMMARIZED. A 1963 STUDY TREATS THE RELATIONSHIP BETWEEN WORK EXPERIENCE AND STUDENT CHARACTERISTICS, PLANS, AND ASPIRATIONS. STUDIES ON POST-SECONDARY EDUCATION CONCERN GUIDELINES FOR TECHNICIAN PROGRAMS, JUSTIFICATION…

  7. Barriers to the Adoption of Sustainable Agriculture on Rented Land: An Examination of Contesting Social Fields

    ERIC Educational Resources Information Center

    Carolan, Michael S.

    2005-01-01

    While over half of the cropland in the United States is rented, interest in land tenancy within sociological circles has been sporadic at best. In light of the prevalence of rented land in agriculture--particularly in the Midwest--it is vital that further research be conducted to investigate the effect that the rental relationship has upon the…

  8. The Impact of Crop, Pest, and Agricultural Management Practices on Mycotoxin Contamination of Field Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mycotoxins are highly toxic secondary metabolites produced by several fungal genera which occur in a wide variety of agricultural commodities worldwide. Health issues and economic losses due to mycotoxin contamination occur at all stages of the food and feed production process. Mycotoxigenic fungi...

  9. 7 CFR Appendix A to Part 3434 - List of Agriculture-Related Fields

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., Environmental Studies 03.0104, Environmental Science 03.0199, Natural Resources Conservation and Research, Other... 01.0307, Horse Husbandry/Equine Science and Management 01.0308, Agroecology and Sustainable... Communication/Journalism 01.0899, Agricultural Public Services, Other 01.0901, Animal Sciences, General...

  10. 7 CFR Appendix A to Part 3434 - List of Agriculture-Related Fields

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., Environmental Studies 03.0104, Environmental Science 03.0199, Natural Resources Conservation and Research, Other... 01.0307, Horse Husbandry/Equine Science and Management 01.0308, Agroecology and Sustainable... Communication/Journalism 01.0899, Agricultural Public Services, Other 01.0901, Animal Sciences, General...

  11. Using lidar to characterize particles from point and diffuse sources in an agricultural field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lidar (LIght Detection And Ranging) provides the means to quantitatively evaluate the spatial and temporal variability of particulate emissions from agricultural activities. Aglite is a three-wavelength portable scanning lidar system built at the Energy Dynamics Laboratory (EDL) to measure the spati...

  12. Validating a high-resolution digital soil map for precision agriculture across multiple fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Digital soil mapping (DSM) for precision agriculture (PA) management is aimed at developing models that predict soil properties or classes using legacy soil data, sensors, and environmental covariates. The utility of DSM for PA is based on its ability to provide useful spatial soil information for o...

  13. The South Carolina Coastal Erosion Study: Nearshore Hydrodynamics Field Experiment

    NASA Astrophysics Data System (ADS)

    Haas, K. A.; Voulgaris, G.; Demir, H.; Work, P. A.; Hanes, D. M.

    2004-12-01

    As part of the South Carolina Coastal Erosion Study (SCCES) a nearshore field experiment was carried out for five days in December 2003 just north of Myrtle Beach, South Carolina, providing measurements of the waves, currents and morphological evolution. This experiment occurred concurrently with an extensive field campaign several kilometers offshore which included measurements of the waves and currents on and near a significant sand shoal. The purpose of the nearshore experiment was to aid in the identification of the effect of the offshore shoal on the nearshore processes. The resulting dataset will be used for verification of numerical models being used to investigate the hydrodynamics of the region. The experiment was carried out from December 10 to December 15 and consisted of measurements of the waves and currents, extensive surveys of the bathymetry every day, grab samples of the sediments, and video imagery. The hydrodynamics were measured using two Sontek Triton downward-looking Acoustic Doppler Velocimeters and two Nortek AquaDopp profilers arranged in a cross-shore line from inside the swash to several surf zone widths past the breakers. The bathymetric surveying was accomplished using both a differential GPS system and a total station. Surveying was performed each day in order to capture the morphological changes. On the last day, seven sediment samples were taken along a single cross-section to determine the sediment characteristics across the beach. Additionally, a video camera was located on a balcony of the top floor of a nearby hotel providing an excellent field of view of the entire experimental area. Digital video was captured directly onto a computer during all daylight hours and many control points were surveyed in each day to facilitate rectification of the imagery. A variety of conditions were encountered during the experiment, including two storm fronts which passed through, generating wind speeds up to 15 m/s. The first storm generated

  14. Celtic field agriculture and Early Anthropogenic Environmental change in the Meuse-Demer-Scheldt region, NW Europe

    NASA Astrophysics Data System (ADS)

    Van der Sanden, Germaine; Kluiving, Sjoerd; Roymans, Nico

    2016-04-01

    The field of Archaeology remains focused on historical issues while underexploring its potential contribution on currently existing societal problems, e.g. climate change. The aim of this paper is to show the relevance of archeological studies for the research of the 'human species as a significant moving agent' in terms of the changing natural environment during a much earlier time frame. This research is based on the study area of the Meuse-Demer-Scheldt region in the Netherlands and Belgium and exhibits the period from the Late Bronze Age to the Early Roman period. This period is characterized by the widespread introduction and use of an agricultural system, often referred to as the Celtic Field system that served as one of the most modifying systems in terms of anthropogenic-environmental change during this period. Emphasis in this research is given to results generated by the use of the remote sensing technology, LiDAR. New information is reported considering a correlation between singular field size and the overall surface of the agricultural complexes and secondly, the presentation of newly identified Celtic field systems in the Meuse-Demer-Scheldt region are presented. The study of the dynamics of the Celtic Field agricultural system provides evidence for a significant anthropogenic footprint on the natural environment due to land cover dominance, soil degeneration, increased soil acidification and forest clearance. Soil exhaustion forced the inhabitants to re-establish their relationship with the landscape in terms of fundamental changes in the habitation pattern and the agrarian exploitations of the land.

  15. Forecasting the Feasibility of Implementing Isolation Perimeters Between GM and non-GM Maize Fields Under Agricultural Conditions

    NASA Astrophysics Data System (ADS)

    Devos, Yann; Cougnon, Mathias; Thas, Olivier; De Clercq, Eva M.; Cordemans, Karl; Reheul, Dirk

    2008-10-01

    Although spatially isolating genetically modified (GM) maize fields from non-GM maize fields is a robust on-farm strategy to keep the adventitious presence of GM material in the harvests of neighboring non-GM maize fields due to cross-fertilizations below established labeling thresholds (and thus to ensure the spatial co-existence between maize cropping systems), the practical implementation of isolation perimeters attracted little research efforts. In this study, the feasibility of implementing isolation perimeters around GM maize fields is investigated. Using Geographic Information System datasets and Monte Carlo simulations, various scenarios differing in shares and spatial distributions of GM maize were tested for various isolation perimeters in six agricultural areas in Flanders. Factors that affect the feasibility of implementing isolation perimeters are discussed.

  16. Selection of flooded agricultural fields and other landscapes by female northern pintails wintering in Tulare Basin, California

    USGS Publications Warehouse

    Fleskes, Joseph P.; Jarvis, Robert L.; Gilmer, David S.

    2003-01-01

    Habitat selection and use are measures of relative importance of habitats to wildlife and necessary information for effective wildlife conservation. To measure the relative impor- tance of flooded agricultural fields and other landscapes to northern pintails (Anas acuta) wintering in Tulare Basin (TB), California, we radiotagged female pintails during late August-early October, 1991-1993 in TB and other San Joaquin Valley areas and deter- mined use and selection of these TB landscapes through March each year. Availability of landscape and field types in TB changed within and among years. Pintail use and selec- tion (based upon use-to-availability log ratios) of landscape and field types differed among seasons, years, and diel periods. Fields flooded after harvest and before planting (i.e., pre-irrigated) were the most available, used, and selected landscape type before the hunting season (Prehunt). Safflower was the most available, used, and-except in 1993, when pre-irrigated fallow was available-selected pre-irrigated field type during Prehunt. Pre-irrigated barley-wheat received 19-22% of use before hunting season, but selection varied greatly among years and diel periods. During and after hunting season, managed marsh was the most available, used, and, along with floodwater areas, selected landscape type; pre-irrigated cotton and alfalfa were the least selected field types and accounted for <13% of pintail use. Agricultural drainwater evaporation ponds, sewage treatment ponds, and reservoirs accounted for 42-48% of flooded landscape available but were lit- tle used and least selected. Exodus of pintails from TB coincided with drying of pre-irri- gated fallow, safflower, and barley-wheat fields early in winter, indicating that preferred habitats were lacking in TB during late winter. Agriculture conservation programs could improve TB for pintails by increasing flooding of fallow and harvested safflower and grain fields. Conservation of remaining wetlands should

  17. Identifying Discrimination at Work: The Use of Field Experiments.

    PubMed

    Pager, Devah; Western, Bruce

    2012-06-01

    Antidiscrimination law offers protection to workers who have been treated unfairly on the basis of their race, gender, religion, or national origin. In order for these protections to be invoked, however, potential plaintiffs must be aware of and able to document discriminatory treatment. Given the subtlety of contemporary forms of discrimination, it is often difficult to identify discrimination when it has taken place. The methodology of field experiments offers one approach to measuring and detecting hiring discrimination, providing direct observation of discrimination in real-world settings. In this article, we discuss the findings of two recent field experiments measuring racial discrimination in low wage labor markets. This research provides several relevant findings for researchers and those interested in civil rights enforcement: (1) it produces estimates of the rate of discrimination at the point of hire; (2) it yields evidence about the interactions associated with discrimination (many of which reveal the subtlety with which contemporary discrimination is practiced); and (3) it provides a vehicle for both research on and enforcement of antidiscrimination law. PMID:24163481

  18. Identifying Discrimination at Work: The Use of Field Experiments

    PubMed Central

    Pager, Devah; Western, Bruce

    2013-01-01

    Antidiscrimination law offers protection to workers who have been treated unfairly on the basis of their race, gender, religion, or national origin. In order for these protections to be invoked, however, potential plaintiffs must be aware of and able to document discriminatory treatment. Given the subtlety of contemporary forms of discrimination, it is often difficult to identify discrimination when it has taken place. The methodology of field experiments offers one approach to measuring and detecting hiring discrimination, providing direct observation of discrimination in real-world settings. In this article, we discuss the findings of two recent field experiments measuring racial discrimination in low wage labor markets. This research provides several relevant findings for researchers and those interested in civil rights enforcement: (1) it produces estimates of the rate of discrimination at the point of hire; (2) it yields evidence about the interactions associated with discrimination (many of which reveal the subtlety with which contemporary discrimination is practiced); and (3) it provides a vehicle for both research on and enforcement of antidiscrimination law. PMID:24163481

  19. Field Studies Show That In Situ Greenhouse Gas Emission Factors for East African Agriculture Are Less Than IPCC Values

    NASA Astrophysics Data System (ADS)

    Pelster, D.; Butterbach-Bahl, K.; Rufino, M.; Rosenstock, T. S.; Wanyama, G.

    2015-12-01

    Greenhouse gas (GHG) emissions from African agricultural systems are thought to comprise a large portion of total emissions from the continent, however these estimates have been calculated using emission factors (EF) from other regions due to the lack of field studies in Africa, which results in large uncertainties for these estimates. Field measurements from western Kenya calculating emissions over a year in 59 different sites found that GHG emissions from typical smallholder farms ranged from 2.8 to 15.0 Mg CO2-C ha-1, -6.0 to 2.4 kg CH4-C ha-1 and -0.1 to 1.8 kg N2O-N ha-1, and were not affected by management intensity. The lack of a response in N2O emissions to N fertilization suggests that the EF currently used in national inventories overestimates N2O emissions from typical smallholder agriculture. Another study measuring N2O and CH4 emissions from manure deposited by grazing cattle found that the N2O EF ranged from 0.1 to 0.2%, while the CH4 EF ranged from 0.04 to 0.14 Kg CH4-C per 173 kg animal. These suggest that the current IPCC EF overestimate agricultural soil and manure GHG emissions for Kenya, and likely for much of East Africa.

  20. Human pharmaceuticals, hormones, and personal care product ingredients in runoff from agricultural fields irrigated with treated wastewater.

    PubMed

    Pedersen, Joel A; Soliman, Mary; Suffet, I H Mel

    2005-03-01

    Irrigation of crops with treated wastewater has the potential to introduce effluent-derived organic microcontaminants into surface waters through agricultural runoff. To determine whether compounds indicative of the presence of treated effluent in irrigation water could be identified in agricultural runoff, surface runoff samples collected from effluent-irrigated and rain-fed cultivated fields were analyzed for a broad spectrum of organic compounds. A variety of compounds was identified that appeared to be associated with irrigation with treated wastewater. These compounds included human pharmaceuticals (e.g., carbamazepine, gemfibrozil, carisoprodol), personal care product ingredients (e.g., insect repellent, polycyclic musks), and alkyl phosphate flame retardant chemicals. Most of these compounds appear not to have been previously reported in agricultural runoff. These compounds were present at concentrations below the few published aquatic toxicology data available; however, their potential to elicit more subtle effects in aquatic organisms cannot be excluded. None of these compounds were detected by broad-spectrum analysis in samples from the same fields during runoff-producing rain events.

  1. Biological and Agricultural Studies on Application of Discharge Plasma and Electromagnetic Fields 5. Effects of High Electric Fields on Animals

    NASA Astrophysics Data System (ADS)

    Isaka, Katsuo

    The biological effects of extremely low frequency electric fields on animals are reviewed with emphasis on studies of the nervous system, behavior, endocrinology, and blood chemistry. First, this paper provides a histrical overview of studies on the electric field effects initiated in Russia and the United States mainly regarding electric utility workers in high voltage substations and transmission lines. Then, the possible mechanisms of electric field effects are explained using the functions of surface electric fields and induced currents in biological objects. The real mechanisms have not yet been identified. The thresholds of electric field perception levels for rats, baboons, and humans are introduced and compared. The experimental results concerning the depression of melatonin secretion in rats exposed to electric fields are described.

  2. Field Experiment Data Support at the Goddard DAAC

    NASA Astrophysics Data System (ADS)

    Hrubiak, P. L.; Yang, R.; Ahmad, S.; Chiu, L.; Teng, W.; Liu, Z.; Serafino, G.; Rui, H.; Bonk, J.; Pollack, N.

    2001-12-01

    Historically, field experiment data support at the data center level has been sketchy, but in the last decade, because of rapid growth of electronic capabilities throughout the science community, the data center has become the resolution of choice to the problems of campaign data distribution and archival. Even so, field campaign data, being inherently non-uniform, require significant adaptation on the part of the archive. The participant complement for a campaign ranges widely-from one to three dozen investigators. Each has his/her own instrument, organizational affiliation, and funding. Many are academics with class schedules to consider, an office staff composed of graduate students and a correspondingly high turnover rate. Some are operating with very limited resources and lack the programming staff to tailor their data to archive specifications. Data delivery schedules, formatting and documentation are all driven by these factors. Planning for data volume also requires flexibility. Campaign data acquisition is sensitive to weather and a variety of logistical problems. Planning for campaign data volume is therefore a matter of determining thresholds. Since most campaign data sets tend to be small by data center standards, distribution is mainly from anonymous ftp sites front-ended by web sites. The Goddard DAAC opened its campaign archive in 1994 with data from the TRMM oriented TOGA-COARE campaign of 1992-93, and has most recently archived the TRMM global validation campaigns, designed to evaluate the physical assumptions made by TRMM rainfall algorithms, initialize and validate the cloud resolving models, test latent heating retrievals from TRMM measurements, and evaluate methods to estimate rainfall and latent heating from ground based radars. Launched by the TRMM Office in 1998, the TRMM campaigns were designed as a group so that specific measurements could be compared between experiments in order to gain insight into the regional dependence of any findings

  3. Linked Data for Fighting Global Hunger:Experiences in setting standards for Agricultural Information Management

    NASA Astrophysics Data System (ADS)

    Baker, Thomas; Keizer, Johannes

    FAO, the Food and Agriculture Organization of the UN, has the global goal to defeat hunger and eliminate poverty. One of its core functions is the generation, dissemination and application of information and knowledge. Since 2000, the Agricultural InformationManagement Standards (AIMS) activity in FAO's Knowledge Exchange and Capacity Building Division has promoted the use of Semantic Web standards to improve information sharing within a global network of research institutes and related partner organizations. The strategy emphasizes the use of simple descriptive metadata, thesauri, and ontologies for integrating access to information from a wide range of sources for both scientific and non-expert audiences. An early adopter of Semantic Web technology, the AIMS strategy is evolving to help information providers in nineteen language areas use modern Linked Data methods to improve the quality of life in developing rural areas, home to seventy percent of the world's poor and hungry people.

  4. Dimensioning IRGA gas sampling systems: laboratory and field experiments

    NASA Astrophysics Data System (ADS)

    Aubinet, Marc; Joly, Lilian; Loustau, Denis; De Ligne, Anne; Chopin, Henri; Cousin, Julien; Chauvin, Nicolas; Decarpenterie, Thomas; Gross, Patrick

    2016-03-01

    Both laboratory and field experiments were carried out in order to define suitable configuration ranges for the gas sampling systems (GSSs) of infrared gas analyzers (IRGAs) used in eddy covariance measurements.

    In the laboratory, an original dynamic calibration bench was developed in order to test the frequency attenuation and pressure drop generated by filters. In the field, three IRGAs of the same type equipped with different filters or different rain caps were installed and run and the real frequency response of the complete setup was tested. The main results are as follows. - Filters may have a strong impact on the pressure drop in the GSS and this impact increases with flow rate. - Conversely, no impact of the tested filters on cut-off frequency was found, GSSs with and without filters presenting similar cut-off frequencies. - The main limiting factor of cut-off frequency in the field was found to be the rain cap design. In addition, the impact of this design on pressure drop was also found to be noteworthy.

  5. Dimensioning IRGA gas sampling system : laboratory and field experiments

    NASA Astrophysics Data System (ADS)

    Aubinet, Marc; Joly, Lilian; Loustau, Denis; De Ligne, Anne; Chopin, Henri; Cousin, Julien; De Carpenterie, Thomas; Gross, Patrick; Chauvin, Nicolas

    2016-04-01

    Both laboratory and field experiments were carried out in order to define suitable configuration ranges for the gas sampling systems (GSS) of infrared gas analyzers (IRGA) used in eddy covariance measurements. In the laboratory, an original dynamic calibration bench was developed in order to test the frequency attenuation and pressure drop generated by filters. In the field, three IRGAs of the same type equipped with different filters or different rain caps were installed and run and the real frequency response of the complete set-up was tested. The main results are that: - Filters may have a strong impact on the pressure drop in the GSS and this impact increases with flow rate. - On the contrary, no impact of the tested filters on cut off frequency was found, GSS with and without filters presenting similar cut off frequencies. - The main limiting factor of cut off frequency in the field was found to be the rain cap design. In addition, the impact of this design on pressure drop was also found noteworthy.

  6. Product amount and quality monitoring in agricultural fields with remote sensing satellite and radio-control helicopter

    NASA Astrophysics Data System (ADS)

    Arai, Kohei

    Product amount and quality monitoring in agricultural fields with remote sensing satellite and radio-control helicopter is proposed. In particular, tealeaves and rice crop quality and amoujnt monitorings are peoposed as examples. Nitrogen rich tealeaves tasts good. Therefore, quality of tealeaves can be estimated with nitrogen content which is related with near infrared reflectance of the tealeves in concern. Also, rice crop quality depends on protein content in rice grain which is related to near infrared reflectance of rice leaves. Therefore, product quality can be estimated with observation of near infrared reflectance of the leaves in concern. Near infared reflectance is provided by near infrared radiometers onboard remote sensing satellites and by near infrared cameras onboard radio-control helicopter. This monitoring system is applicable to the other agricultural plant products. Through monitoring near ingfrared reflectance, it is possible to estimate quality as well as product amount.

  7. Hemisphere-specific treatment of dyslexia subtypes: a field experiment.

    PubMed

    Bakker, D J; Bouma, A; Gardien, C J

    1990-01-01

    Evidence is discussed to show that so-called L- and P-type dyslexia result from deviations in the development of hemispheric subservience in learning to read. Investigations into the validity of the L/P classification are reviewed, as are laboratory experiments on the effects of so-called hemisphere-specific stimulation (HSS). In the present field experiment, 28 L-dyslexic children (mean chronological and reading age 10.6 and 7.5 years, respectively) received HSS of the right hemisphere by the presentation of words to the fingers of the left hand, and 26 P-dyslexic children (mean chronological and reading age 9.4 and 7.2 years, respectively) received HSS of the left hemisphere by the presentation of words to the fingers of the right hand. Control L and P subjects were treated according to the discretion of the remedial teacher. The results underscore the findings of previous laboratory experiments in that (a) HSS-treated L-dyslexics, relative to controls, tended to show larger improvement of accuracy in text reading; and (b) HSS-treated P-dyslexics, relative to controls, showed larger improvement of fluency in word reading. PMID:2398315

  8. Field experiments using SPEAR: a speech control system for UGVs

    NASA Astrophysics Data System (ADS)

    Chhatpar, Siddharth R.; Blanco, Chris; Czerniak, Jeffrey; Hoffman, Orin; Juneja, Amit; Pruthi, Tarun; Liu, Dongqing; Karlsen, Robert; Brown, Jonathan

    2009-05-01

    This paper reports on a Field Experiment carried out by the Human Research and Engineering Directorate at Ft. Benning to evaluate the efficacy of using speech to control an Unmanned Ground Vehicle (UGV) concurrently with a handcontroller. The SPEAR system, developed by Think-A-Move, provides speech-control of UGVs. The system picks up user-speech in the ear canal with an in-ear microphone. This property allows it to work efficiently in high-noise environments, where traditional speech systems, employing external microphones, fail. It has been integrated with an iRobot PackBot 510 with EOD kit. The integrated system allows the hand-controller to be supplemented with speech for concurrent control. At Ft. Benning, the integrated system was tested by soldiers from the Officer Candidate School. The Experiment had dual focus: 1) Quantitative measurement of the time taken to complete each station and the cognitive load on users; 2) Qualitative evaluation of ease-of-use and ergonomics through soldier-feedback. Also of significant benefit to Think-A-Move was soldier-feedback on the speech-command vocabulary employed: What spoken commands are intuitive, and how the commands should be executed, e.g., limited-motion vs. unlimited-motion commands. Overall results from the Experiment are reported in the paper.

  9. Transverse dispersion: From laboratory experiments to field applications

    NASA Astrophysics Data System (ADS)

    Grathwohl, Peter; Rügner, Hermann

    2016-04-01

    Transverse dispersion is relevant for dilution of contaminant plumes in groundwater and in many cases controls the length of steady state plumes during natural attenuation. Also dissolution kinetics of NAPLs in porous media and mass transfer of vapor phase compounds across the capillary fringe (e.g. supply of oxygen) is limited by transverse dispersion. In bench scale laboratory experiments typically very small dispersion coefficients are observed. Transverse dispersivities determined in DNAPL pool dissolution experiments in coarse sands are less than 0.1 mm which agrees with results from lab experiments on dilution of tracers and transfer of oxygen across the capillary fringe. Such low dispersivities lead to long-term persistence of DNAPL pools of many decades to centuries which is confirmed e.g. for chlorinated solvents and coal tars by observations at contaminated sites. However, larger scale investigations, e.g. determination of the length of steady state plumes or reduction of mass fluxes of biodegradable compounds suggest that transverse dispersivities at field scale are up to 3 orders of magnitude higher (1 -10 cm). Reasons for this discrepancy are still unclear, but may be partly explained by processes enhancing transverse mixing such as flow focusing due to aquifer geometries or high permeability inclusions and helical groundwater flow induced by herringbone structures in sediments.

  10. Data management for interdisciplinary field experiments: OTTER project support

    NASA Technical Reports Server (NTRS)

    Angelici, Gary; Popovici, Lidia; Skiles, J. W.

    1993-01-01

    The ability of investigators of an interdisciplinary science project to properly manage the data that are collected during the experiment is critical to the effective conduct of science. When the project becomes large, possibly including several scenes of large-format remotely sensed imagery shared by many investigators requiring several services, the data management effort can involve extensive staff and computerized data inventories. The OTTER (Oregon Transect Ecosystem Research) project was supported by the PLDS (Pilot Land Data System) with several data management services, such as data inventory, certification, and publication. After a brief description of these services, experiences in providing them are compared with earlier data management efforts and some conclusions regarding data management in support of interdisciplinary science are discussed. In addition to providing these services, a major goal of this data management capability was to adopt characteristics of a pro-active attitude, such as flexibility and responsiveness, believed to be crucial for the effective conduct of active, interdisciplinary science. These are also itemized and compared with previous data management support activities. Identifying and improving these services and characteristics can lead to the design and implementation of optimal data management support capabilities, which can result in higher quality science and data products from future interdisciplinary field experiments.

  11. Agricultural communication and the African non-literate farmer: the Nigerian experience.

    PubMed

    Soola, E O

    1988-01-01

    In Nigeria, there lies a relatively untapped potential for great agricultural growth. Since the 1960's, Nigeria's "days of agricultural glory," there has been great obstacles in the exchange of information between scientists and Nigerian farmers. There has been a great trend in rural-urban migration and a rise in unemployment; crime and school drop outs have ensued. The Nigerian non-literate farmer is in a neglected class who has suffered the scrutiny and non-support of government and financial institutions. His growth has been limited because he is considered a poor credit risk. Because of his illiteracy, he is limited to traditional methods of farming. However, the Nigerian farmer is not uneducable. He is information-conscious and can be instructed if a communicator is sensitive to the farmer's culture, tradition and farming practices. An agriculture extension agent must not only assess the farmer's needs but also convey relevant information in a manner that is amenable to the farmer's framework of communication. Working with opinion leaders, the mass media, a regional library, audio tapes and by portraying new information and farming practices through festivals and ceremonies are methods available to the extension agent or communicator in his work with the non-literate Nigerian farmer.

  12. Death and disability from agricultural injuries in Wisconsin: a 12-year experience with 739 patients.

    PubMed

    Cogbill, T H; Steenlage, E S; Landercasper, J; Strutt, P J

    1991-12-01

    During a 12-year period, 739 patients were admitted to a referral trauma center as the result of injuries incurred while farming. There were 608 (82%) male patients and 131 female patients. Ages ranged from 1 to 89 years including 160 patients (22%) less than 16 years old and 78 patients (11%) more than 65 years old. The injury mechanism was a farm animal in 225 (30%), farm machinery in 168 (23%), a tractor in 120 (16%), a fall in 77 (10%), a power take-off in 47 (7%), a cornpicker in 42 (6%), and miscellaneous in 60 (8%). There were 16 (2%) deaths attributable to the agricultural accident. Tractors were involved in eight of these deaths, falls in four, power take-offs in three, and farm machinery in one. Furthermore, 159 (22%) patients were left with significant permanent disability including orthopedic problems in 131 patients, neurologic deficits in 22, and pulmonary disability in 6. Agricultural trauma is frequent and diverse with unique injury mechanisms. Life-threatening injuries are often seen and permanent disability is common. Effective injury prevention must focus on farmer education, additional mandatory safety features on agricultural equipment, and appropriate design of rural trauma systems. PMID:1749035

  13. Electric Field Double Probe Measurements for Ionospheric Space Plasma Experiments

    NASA Technical Reports Server (NTRS)

    Pfaff, R.

    1999-01-01

    Double probes represent a well-proven technique for gathering high quality DC and AC electric field measurements in a variety of space plasma regimes including the magnetosphere, ionosphere, and mesosphere. Such experiments have been successfully flown on a variety of spacecraft including sounding rockets and satellites. Typical instrument designs involve a series of trades, depending on the science objectives, type of platform (e.g., spinning or 3-axis stabilized), expected plasma regime where the measurements will be made, available telemetry, budget, etc. In general, ionospheric DC electric field instruments that achieve accuracies of 0.1 mV/m or better, place spherical sensors at large distances (10m or more) from the spacecraft body in order to extend well beyond the spacecraft wake and sheath and to achieve large signal-to-noise ratios for DC and long wavelength measurements. Additional sets of sensors inboard of the primary, outermost sensors provide useful additional information, both for diagnostics of the plasma contact potentials, which particularly enhance the DC electric field measurements on non-spinning spacecraft, and for wavelength and phase velocity measurements that use the spaced receiver or "interferometer" technique. Accurate attitude knowledge enables B times V contributions to be subtracted from the measured potentials, and permits the measured components to be rotated into meaningful geophysical reference frames. We review the measurement technique for both DC and wave electric field measurements in the ionosphere discussing recent advances involving high resolution burst memories, multiple baseline double probes, new sensor surface materials, biasing techniques, and other considerations.

  14. Nitrate-nitrogen and oxygen isotope ratios for identification of nitrate sources and dominant nitrogen cycle processes in a tile-drained dryland agricultural field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural systems are a leading source of reactive nitrogen to aquatic and atmospheric ecosystems. Natural d15Nnitrate and d18Onitrate are used to identify the dominant nitrogen cycle processes and sources of NO3- leached from a tile-drained, dryland agricultural field. Tile-drain water discharge...

  15. Application of ERTS-1 imagery in the fields of geology, agriculture, forestry, and hydrology to selected test sites in Iran

    NASA Technical Reports Server (NTRS)

    Ebtehadj, K.

    1973-01-01

    The preliminary study of the ERTS-1 imagery coverage of Iran, commenced on October 26, 1972. All of the images were carefully examined, and a photomosaic covering approximately ninety-five per cent of the country was prepared. A number of images of selected areas were studied in detail. In the field of geology, a number of large scale faults were identified, which do not figure on geological maps. Furthermore, a preliminary study was carried out on the recent sediments, their possible sources, and origin. A limited number of geological work maps were prepared as well. In the fields of agriculture and forestry, studies based on color composite prints of certain areas were undertaken, with a purpose of identifying potential arable areas. Investigations in the field of water resources resulted in the discovery of a number of small lakes, and streams. Furthermore, fluctuations of the water level in some lakes were observed.

  16. Mercury's Gravity Field from BepiColombo MORE experiment

    NASA Astrophysics Data System (ADS)

    Marabucci, M.; Genova, A.; Iess, L.

    2012-04-01

    The Mercury Orbiter Radioscience Experiment (MORE) is one of the main instruments on board the BepiColombo Mercury Planetary Orbiter (MPO), designed to provide an accurate estimation of Mercury's gravity field by means of highly stable, multi-frequency radio links in X and Ka band. The state-of-the-art microwave equipment enables simultaneous two-way links in X/X (7.2 GHz uplink/8.4 GHz downlink), X/Ka (7.2/32.5 GHz) and Ka/Ka band (34/32.5 GHz), providing range rate accuracies of 3 micron/s (at 1000 s integration time) at nearly all elongation angles. Range observables accurate to 20 cm (two-way) will be attained using a novel, wideband (24 Mcps) ranging system, based upon a pseudo-noise modulation scheme. The multifrequency link, adopted for the first time by the Cassini mission to Saturn [1,2], allows a nearly complete cancellation of the plasma noise both in Doppler and range measurements and hence an accurate determination of Mercury's gravity field and ephemerides. The orbit determination of spacecraft in deep space is generally carried out by means of batch filters, for recovering the trajectory and the model parameters (i.e. gravity field coefficients). The complexity of Mercury's environment penalizes strongly the accuracy of the orbit determination because of the non-gravitational perturbations, such as the solar radiation pressure. Although the non-gravitational accelerations of the MPO will be measured by a highly sensitive accelerometer (the Italian Spring Accelerometer, ISA), a classical, global batch filter proved to be inadequate for precise orbit propagation due to numerical instabilities. Therefore, a different approach has been devised, where the information accumulated previously is exploited in a batch-sequential filter. This paper reports on a new set of numerical simulations carried out with this strategy. The simulation setup takes into account the latest changes in the spacecraft design, the mission profile and the tracking system. We

  17. Microwave Remote Sensing and the Cold Land Processes Field Experiment

    NASA Technical Reports Server (NTRS)

    Kim, Edward J.; Cline, Don; Davis, Bert; Hildebrand, Peter H. (Technical Monitor)

    2001-01-01

    The Cold Land Processes Field Experiment (CLPX) has been designed to advance our understanding of the terrestrial cryosphere. Developing a more complete understanding of fluxes, storage, and transformations of water and energy in cold land areas is a critical focus of the NASA Earth Science Enterprise Research Strategy, the NASA Global Water and Energy Cycle (GWEC) Initiative, the Global Energy and Water Cycle Experiment (GEWEX), and the GEWEX Americas Prediction Project (GAPP). The movement of water and energy through cold regions in turn plays a large role in ecological activity and biogeochemical cycles. Quantitative understanding of cold land processes over large areas will require synergistic advancements in 1) understanding how cold land processes, most comprehensively understood at local or hillslope scales, extend to larger scales, 2) improved representation of cold land processes in coupled and uncoupled land-surface models, and 3) a breakthrough in large-scale observation of hydrologic properties, including snow characteristics, soil moisture, the extent of frozen soils, and the transition between frozen and thawed soil conditions. The CLPX Plan has been developed through the efforts of over 60 interested scientists that have participated in the NASA Cold Land Processes Working Group (CLPWG). This group is charged with the task of assessing, planning and implementing the required background science, technology, and application infrastructure to support successful land surface hydrology remote sensing space missions. A major product of the experiment will be a comprehensive, legacy data set that will energize many aspects of cold land processes research. The CLPX will focus on developing the quantitative understanding, models, and measurements necessary to extend our local-scale understanding of water fluxes, storage, and transformations to regional and global scales. The experiment will particularly emphasize developing a strong synergism between process

  18. The strategic logic of costly punishment necessitates natural field experiments, and at least one such experiment exists.

    PubMed

    Johnson, Tim

    2012-02-01

    Costly punishment's scarcity "in the wild" does not belie strong reciprocity theory as Guala claims. In the presence of strong reciprocators, strategic defectors will cooperate and sanctioning will not occur. Accordingly, natural field experiments are necessary to assess a "wide" reading of costly punishment experiments. One such field experiment exists, and it supports the hypothesis that costly punishment promotes cooperation.

  19. An Examination of the Opinions and Supervised Occupational Experience Programs of Selected Vocational Agricultural Instructors in the U.S. Staff Study.

    ERIC Educational Resources Information Center

    Bobbitt, Frank

    A study was made of the opinions and programs of a selected group of 77 vocational agriculture instructors to determine the status of supervised occupational experience (SOE) programs among secondary agricultural instructors who had been identified as some of the best in the states surveyed. Of particular interest was the relative role that the…

  20. Field experiment, anaerobic biodegradation of highly chlorinated aromatics

    SciTech Connect

    Duffy, J.; Baek, N.; Coates, M.

    1995-12-31

    The objective of the field experiment is to evaluate the effectiveness of anaerobic biodegradation of chlorinated benzenes and toluenes. Excavated soil from a chemical manufacturing site was saturated to maintain anaerobic conditions and treated with nutrients (butyrate, yeast extract, and glucose). One sample was treated with nutrients and microbial inoculation. Preliminary results for the first 24 weeks showed that higher chlorinated benzene concentrations are reduced with an increase of concentrations of lower halogenated species, resulting from deahalogenation. No significant change in the concentrations of chlorinated toluenes was observed during this period. This is consistent with earlier laboratory work in which benzene dehalogenation preceded toluene dehalogenation. Rapid consumption of butyrate and sulfate was also observed.

  1. Use of multitemporal SPOT data in first ISLSCP field experiment

    NASA Technical Reports Server (NTRS)

    Asrar, Ghassem; Murphy, R. E.; Hall, F. G.; Sellers, P. J.

    1991-01-01

    The use of multitemporal SPOT data in a coordinated field experiment is described with objectives to understand the processes that control the biosphere-atmosphere exchanges of heat, mass, momentum and radiation at a range of spatial and temporal scales; and quantify processes associated with these biosphere-atmosphere exchanges with the aid of multispectral and multitemporal remotely sensed data. The study was conducted in a 15 sq km area located in the tall grass prairie region of midwestern U.S. over a period of three years from 1987 through 1989. A combination of ground based, airborne and space based remotely sensed data were used in a variety of interdisciplinary investigations. An overview of the results from studies that used SPOT multispectral and multitemporal data is presented.

  2. Prosocial Behavior and Subjective Insecurity in Violent Contexts: Field Experiments.

    PubMed

    Vélez, María Alejandra; Trujillo, Carlos Andres; Moros, Lina; Forero, Clemente

    2016-01-01

    Subjective insecurity is a key determinant of different forms of prosocial behavior. In Study 1, we used field experiments with farmers in Colombian villages exposed to different levels of violence to investigate how individual perceptions of insecurity affect cooperation, trust, reciprocity and altruism. To do so, we developed a cognitive-affective measure of subjective insecurity. We found that subjective insecurity has a negative effect on cooperation but influences trust and altruism positively. In Study 2, carried out three years after Study 1, we repeated the initial design with additional measures of victimization. Our goal was to relate subjective insecurity with actual victimization. The findings of Study 2 support the initial results, and are robust and consistent for cooperative behavior and trust when including victimization as a mediator. Different indicators of victimization are positively correlated with subjective insecurity and an aggregate index of victimization has a negative effect on cooperation but exerts a positive influence on trust. PMID:27472437

  3. Prosocial Behavior and Subjective Insecurity in Violent Contexts: Field Experiments

    PubMed Central

    Vélez, María Alejandra; Trujillo, Carlos Andres; Moros, Lina; Forero, Clemente

    2016-01-01

    Subjective insecurity is a key determinant of different forms of prosocial behavior. In Study 1, we used field experiments with farmers in Colombian villages exposed to different levels of violence to investigate how individual perceptions of insecurity affect cooperation, trust, reciprocity and altruism. To do so, we developed a cognitive-affective measure of subjective insecurity. We found that subjective insecurity has a negative effect on cooperation but influences trust and altruism positively. In Study 2, carried out three years after Study 1, we repeated the initial design with additional measures of victimization. Our goal was to relate subjective insecurity with actual victimization. The findings of Study 2 support the initial results, and are robust and consistent for cooperative behavior and trust when including victimization as a mediator. Different indicators of victimization are positively correlated with subjective insecurity and an aggregate index of victimization has a negative effect on cooperation but exerts a positive influence on trust. PMID:27472437

  4. Soil response to chemicals used in a field experiment

    NASA Astrophysics Data System (ADS)

    Jezierska-Tys, S.; Rutkowska, A.

    2013-03-01

    The effect of chemicals (Reglone 200 SL and Elastiq 550 EC) on soil microorganisms and their enzymatic activity was estimated. The study was conducted in a field experiment which was set up in the split-block design and comprised three treatments. Soil samples were taken six times, twice in each year of study. The results showed that the application of chemicals generally had no negative effect on the number of soil microorganisms. The application of Reglone 200 SL caused an increase of proteolytic and ureolytic activity and affected the activity of dehydrogenases, acid and alkaline phosphatases in the soil. The soil subjected of Elastiq 550 EC was characterized by lower activity of dehydrogenases, protease, urease and alkaline phosphatase.

  5. Modelling Water Flow, Heat Transport, Soil Freezing and Thawing, and Snow Processes in a Clayey, Subsurface Drained Agricultural Field

    NASA Astrophysics Data System (ADS)

    Warsta, L.; Turunen, M.; Koivusalo, H. J.; Paasonen-Kivekäs, M.; Karvonen, T.; Taskinen, A.

    2012-12-01

    Simulation of hydrological processes for the purposes of agricultural water management and protection in boreal environment requires description of winter time processes, including heat transport, soil freezing and thawing, and snow accumulation and melt. Finland is located north of the latitude of 60 degrees and has one third to one fourth of the total agricultural land area (2.3 milj. ha) on clay soils (> 30% of clay). Most of the clayey fields are subsurface drained to provide efficient drainage and to enable heavy machines to operate on the fields as soon as possible after the spring snowmelt. Generation of drainflow and surface runoff in cultivated fields leads to nutrient and sediment load, which forms the major share of the total load reaching surface waters at the national level. Water, suspended sediment, and soluble nutrients on clayey field surface are conveyed through the soil profile to the subsurface drains via macropore pathways as the clayey soil matrix is almost impermeable. The objective of the study was to develop the missing winter related processes into the FLUSH model, including soil heat transport, snow pack simulation and the effects of soil freezing and thawing on the soil hydraulic conductivity. FLUSH is an open source (MIT license), distributed, process-based model designed to simulate surface runoff and drainflow in clayey, subsurface drained agricultural fields. 2-D overland flow is described with the diffuse wave approximation of the Saint Venant equations and 3-D subsurface flow with a dual-permeability model. Both macropores and soil matrix are simulated with the Richards equation. Soil heat transport is described with a modified 3-D convection-diffusion equation. Runoff and groundwater data was available from different periods from January 1994 to April 1999 measured in a clayey, subsurface drained field section (3.6 ha) in southern Finland. Soil temperature data was collected in two locations (to a depth of 0.8 m) next to the

  6. Interactively Improving Agricultural Field Mapping in Sub-Saharan Africa with Crowd-Sourcing and Active Learning

    NASA Astrophysics Data System (ADS)

    Debats, S. R.; Estes, L. D.; Caylor, K. K.

    2015-12-01

    As satellite imagery becomes increasingly available, management of large image databases becomes more important for efficient image processing. We have developed a computer vision-based classification algorithm to distinguish smallholder agricultural land cover in Sub-Saharan Africa, using a group of high-resolution images from South Africa as a case study. For supervised classification, smallholder agriculture, with ambiguous patterns of small, irregular fields, requires a wide range of training data samples to adequately describe the variability in appearance. We employ crowd-sourcing to obtain new training data to expand the geographic range of our algorithm. A crowd-sourcing user is asked to hand-digitize the boundaries of agricultural fields in an assigned 1 km2 image. Yet random assignment of images to users could result in a highly redundant training data set with limited discriminative power. Furthermore, larger training data sets require a greater number of users to hand-digitize fields, which increases costs through crowd-sourcing engines like Amazon Mechanical Turk, as well as longer algorithm training times, which increases computing costs. Therefore, we employ an active learning approach to interactively select the most informative images to be hand-digitized for training data by crowd-sourcing users, based on changes in algorithm accuracy. We investigate the use of various image similarity measures used in content-based image retrieval systems, which quantify the distance, such as Euclidean distance or Manhattan distance, between a variety of extracted feature spaces to determine how similar the content of two images are. We determine the minimum training data set needed to maximize algorithm accuracy, as well as automate the selection of additional training images to classify a new target image that expands the geographic range of our algorithm.

  7. Biodiversity in Organic Farmland - How Does Landscape Context Influence Species Diversity in Organic Vs. Conventional Agricultural Fields?

    NASA Astrophysics Data System (ADS)

    Seufert, V.; Wood, S.; Reid, A.; Gonzalez, A.; Rhemtulla, J.; Ramankutty, N.

    2014-12-01

    The most important current driver of biodiversity loss is the conversion of natural habitats for human land uses, mostly for the purpose of food production. However, by causing this biodiversity loss, food production is eroding the very same ecosystem services (e.g. pollination and soil fertility) that it depends on. We therefore need to adopt more wildlife-friendly agricultural practices that can contribute to preserving biodiversity. Organic farming has been shown to typically host higher biodiversity than conventional farming. But how is the biodiversity benefit of organic management dependent on the landscape context farms are situated in? To implement organic farming as an effective means for protecting biodiversity and enhancing ecosystem services we need to understand better under what conditions organic management is most beneficial for species. We conducted a meta-analysis of the literature to answer this question, compiling the most comprehensive database to date of studies that monitored biodiversity in organic vs. conventional fields. We also collected information about the landscape surrounding these fields from remote sensing products. Our database consists of 348 study sites across North America and Europe. Our analysis shows that organic management can improve biodiversity in agricultural fields substantially. It is especially effective at preserving biodiversity in homogeneous landscapes that are structurally simplified and dominated by either cropland or pasture. In heterogeneous landscapes conventional agriculture might instead already hold high biodiversity, and organic management does not appear to provide as much of a benefit for species richness as in simplified landscapes. Our results suggest that strategies to maintain biodiversity-dependent ecosystem services should include a combination of pristine natural habitats, wildlife-friendly farming systems like organic farming, and high-yielding conventional systems, interspersed in structurally

  8. Spatial variability of soil magnetic susceptibility in an agricultural field located in Eastern Ukraine

    NASA Astrophysics Data System (ADS)

    Menshov, Oleksandr; Pereira, Paulo; Kruglov, Oleksandr

    2015-04-01

    Magnetic susceptibility (MS) have been used to characterize soil properties. It gives an indirect information about heavy metals content and degree of human impacts on soil contamination derived from atmospheric pollution (Girault et al., 2011). This method is inexpensive in relation to chemical analysis and very useful to track soil pollution, since several toxic components deposited on soil surface are rich in particulates produced by oxidation processes (Boyko et al., 2004; Morton-Bernea et al., 2009). Thus, identify the spatial distribution of MS is of major importance, since can give an indirect information of high metals content (Dankoub et al., 2012). This allows also to distinguish the pedogenic and technogenic origin magnetic signal. For example Ukraine chernozems contain fine-grained oxidized magnetite and maghemite of pedogenic origin formed by weathering of the parent material (Jeleńska et al., 2004). However, to a correct understanding of variables distribution, the identification of the most accurate interpolation method is fundamental for a better interpretation of map information (Pereira et al., 2013). The objective of this work is to study the spatial variability of soil MS in an agricultural fields located in the Tcherkascy Tishki area (50.11°N, 36.43 °E, 162 m a.s.l), Ukraine. Soil MS was measured in 77 sampling points in a north facing slope. To estimate the best interpolation method, several interpolation methods were tested, as inverse distance to a weight (IDW) with the power of 1,2,3,4 and 5, Local Polynomial (LP) with the power of 1 and 2, Global Polynomial (GP), radial basis functions - spline with tension (SPT), completely regularized spline (CRS), multiquatratic (MTQ), inverse multiquatratic (IMTQ), and thin plate spline (TPS) - and some geostatistical methods as, ordinary kriging (OK), Simple Kriging (SK) and Universal Kriging (UK), used in previous works (Pereira et al., 2014). On average, the soil MS of the studied plot had 686

  9. Spatial variability of soil magnetic susceptibility in an agricultural field located in Eastern Ukraine

    NASA Astrophysics Data System (ADS)

    Menshov, Oleksandr; Pereira, Paulo; Kruglov, Oleksandr

    2015-04-01

    Magnetic susceptibility (MS) have been used to characterize soil properties. It gives an indirect information about heavy metals content and degree of human impacts on soil contamination derived from atmospheric pollution (Girault et al., 2011). This method is inexpensive in relation to chemical analysis and very useful to track soil pollution, since several toxic components deposited on soil surface are rich in particulates produced by oxidation processes (Boyko et al., 2004; Morton-Bernea et al., 2009). Thus, identify the spatial distribution of MS is of major importance, since can give an indirect information of high metals content (Dankoub et al., 2012). This allows also to distinguish the pedogenic and technogenic origin magnetic signal. For example Ukraine chernozems contain fine-grained oxidized magnetite and maghemite of pedogenic origin formed by weathering of the parent material (Jeleńska et al., 2004). However, to a correct understanding of variables distribution, the identification of the most accurate interpolation method is fundamental for a better interpretation of map information (Pereira et al., 2013). The objective of this work is to study the spatial variability of soil MS in an agricultural fields located in the Tcherkascy Tishki area (50.11°N, 36.43 °E, 162 m a.s.l), Ukraine. Soil MS was measured in 77 sampling points in a north facing slope. To estimate the best interpolation method, several interpolation methods were tested, as inverse distance to a weight (IDW) with the power of 1,2,3,4 and 5, Local Polynomial (LP) with the power of 1 and 2, Global Polynomial (GP), radial basis functions - spline with tension (SPT), completely regularized spline (CRS), multiquatratic (MTQ), inverse multiquatratic (IMTQ), and thin plate spline (TPS) - and some geostatistical methods as, ordinary kriging (OK), Simple Kriging (SK) and Universal Kriging (UK), used in previous works (Pereira et al., 2014). On average, the soil MS of the studied plot had 686

  10. Turbulent Dispersion of Pathogenic Spores Within and Above Plant Canopies: Field Experiments and Lagrangian Modeling

    NASA Astrophysics Data System (ADS)

    Gleicher, S.; Chamecki, M.; Isard, S.; Katul, G. G.

    2012-12-01

    Plant disease epidemics caused by pathogenic spores are a common and consequential threat to agricultural crops. In most cases, pathogenic spores are produced and released deep inside plant canopies and must be transported out of the canopy region in order to infect other fields and spread the disease. The fraction of spores that "escape" the canopy is crucial in determining how fast and far these plant diseases will spread. The goal of this work is to use a field experiment, coupled with a Lagrangian Stochastic Model (LSM), to investigate how properties of canopy turbulence impact the dispersion of spores inside the canopy and the fraction of spores that escape from the canopy. An extensive field experiment was conducted to study spore dispersion inside and outside a corn canopy. The spores were released from point sources located at various depths inside the canopy. Concentration measurements were obtained inside and above the canopy by a 3-dimensional grid of spore collectors. The experimental measurements of mean spore concentration are used to validate a LSM for spore dispersion. In the LSM, flow field statistics used to drive the particle dispersion are specified by a second-order closure model for turbulence within plant canopies. The dispersion model includes spore deposition on and rebound from canopy elements. The combination of experimental and numerical simulations is used to quantify the fraction of spores that escape the canopy. Effects of release height, friction velocity, and canopy architecture on the escape fraction of spores are explored using the LSM, and implications for disease propagation are discussed.

  11. Frac-and-pack stimulation: Application, design, and field experience

    SciTech Connect

    Roodhart, L.P.; Fokker, P.A.; Davies, D.R.; Shlyapobersky, J.; Wong, G.K.

    1994-03-01

    This paper discusses the criteria for selecting wells to be frac-and-packed. The authors show how systematic study of the inflow performance can be used to assess the potential of frac-and-packed wells, to identify the controlling factors, and to optimize design parameters. They also show that fracture conductivity is often the key to successful treatment. This conductivity depends largely on proppant size; formation permeability damage around the created fracture has less effect. Appropriate allowance needs to be made for flow restrictions caused by the presence of the perforations, partial penetration, and non-Darcy effects. They describe the application of the overpressure-calibrated hydraulic fracture model in frac-and-pack treatment design, and discuss some operational considerations with reference to field examples. The full potential of this promising new completion method can be achieved only if the design is tailored to the individual well. This demands high-quality input data, which can be obtained only from a calibration test. This paper presents their strategy for frac-and-pack design, drawing on examples from field experience. They also point out several areas that the industry needs to address, such as the sizing of proppant in soft formations and the interaction between fracturing fluids and resin in resin-coated proppant.

  12. The field experiments on the HTO washout from the atmosphere

    SciTech Connect

    Golubev, A.V.; Mavrin, S.V.; Golubeva, V.N.; Stengach, A.V.; Balashov, Y.S.; Kovalenko, V.P.; Solomatin, I.I.

    2015-03-15

    HTO (tritiated water) wash-out from the atmosphere is one of the key processes governing the HTO transport from the atmosphere into soil and plants. Experimental studies of the HTO interaction with water drops were carried out both in laboratories and in the field. In the course of experiments, the following rain characteristics were recorded: rain intensity, size distribution of drops, and falling velocities and their dependence on drop diameter. A laser optical device was designed and used to measure the distribution of the drop radius and velocities during the period of experiment. The tritium source was placed at a height of 30 m. Rainwater samples were collected in plastic bottles and their HTO activity was determined by liquid scintillation techniques. The data obtained for the experimental values of the scavenging rate are within the range from 4.12*10{sup -5} to 1.57*10{sup -4} s{sup -1} and correspond to the precipitation intensity from 0.3 to 1.26 mm/hour. These results are in sufficiently good agreement with the results of earlier papers.

  13. Utility of thermal image sharpening for monitoring field-scale evapotranspiration over rainfed and irrigated agricultural regions

    NASA Astrophysics Data System (ADS)

    Agam, Nurit; Kustas, William P.; Anderson, Martha C.; Li, Fuqin; Colaizzi, Paul D.

    2008-01-01

    The utility of a thermal image sharpening algorithm (TsHARP) in providing fine resolution land surface temperature data to a Two-Source-Model for mapping evapotranspiration (ET) was examined over two agricultural regions in the U.S. One site is in a rainfed corn and soybean production region in central Iowa. The other lies within the Texas High Plains, an irrigated agricultural area. It is concluded that in the absence of fine (sub-field scale) resolution thermal data, TsHARP provides an important tool for monitoring ET over rainfed agricultural areas. In contrast, over irrigated regions, TsHARP applied to kilometer-resolution thermal imagery is unable to provide accurate fine resolution land surface temperature due to significant sub-pixel moisture variations that are not captured in the sharpening procedure. Consequently, reliable estimation of ET and crop stress requires thermal imagery acquired at high spatial resolution, resolving the dominant length-scales of moisture variability present within the landscape.

  14. Chemical and biological characterization of products of incomplete combustion from the simulated field burning of agricultural plastic

    SciTech Connect

    Ryan, J.V.; Perry, E.; Linak, W.P.; DeMarini, D.M.; Williams, R.W.

    1989-01-01

    Chemical and biological analyses were performed to characterize products of incomplete combustion emitted during the simulated open-field burning of agricultural plastic. A small utility shed equipped with an air delivery system was used to simulate pile burning and forced-air-curtain incineration of a nonhalogenated agricultural plastic that reportedly consisted of polyethylene and carbon black. Emissions were analyzed for combustion gases; volatile, semi-volatile, and particulate organics; and toxic and mutagenic properties. Emission samples, as well as samples of the used (possibly pesticide-contaminated) plastic, were analyzed for the presence of several pesticides to which the plastic may have been exposed. When mutagenicity was evaluated by exposing Salmonella bacteria (Ames assay) to whole vapor and vapor/particulate emissions, no toxic or mutagenic effects were observed. However, organic extracts of the particulate samples were moderately mutagenic. The study highlights the benefits of a combined chemical/biological approach to the characterization of complex, multi-component combustion emissions. These results may not reflect those of other types of plastic that may be used for agricultural purposes, especially those containing halogens.

  15. Deriving hydraulic roughness from camera-based high resolution topography in field and laboratory experiments

    NASA Astrophysics Data System (ADS)

    Kaiser, Andreas; Neugirg, Fabian; Ebert, Louisa; Haas, Florian; Schmidt, Jürgen; Becht, Michael; Schindewolf, Marcus

    2016-04-01

    The hydraulic roughness, represented by Manning's n, is an essential input parameter in physically based soil erosion modeling. In order to acquire the roughness values for certain areas, on-site flow experiments have to be carried out. These results are influenced by the selection of the location of the test plot and are thereby based on the subjectiveness of the researchers. The study aims on the methodological development to acquire Manning's n by creating very high-resolution surface models with structure-from-motion approaches. Data acquisition took place during several field experiments in the Lainbach valley, southern Germany, and on agricultural sites in Saxony, eastern Germany, and in central Brazil. Rill and interrill conditions were simulated by flow experiments. In order to validate our findings stream velocity as an input for the manning equation was measured with coloured dye. Grain and aggregate sizes were derived by measuring distances from a best fit line to the reconstructed soil surface. Several diameters from D50 to D90 were tested with D90 showing best correlation between tracer experiments and photogrammetrically acquired data. A variety of roughness parameters were tested (standard deviation, random roughness, Garbrecht's n and D90). Best agreement in between the particle size and the hydraulic roughness was achieved with a non-linear sigmoid function and D90 rather than with the Garbrecht equation or statistical parameters. To consolidate these findings a laboratory setup was created to reproduce field data under controlled conditions, excluding unknown influences like infiltration and changes in surface morphology by erosion.

  16. Experience from use of GMOs in Argentinian agriculture, economy and environment.

    PubMed

    Burachik, Moisés

    2010-11-30

    Argentina is the second largest grower of genetically modified (GM) crops. This high level of adoption of this new agricultural technology is the result of a complex combination of circumstances. We can identify four main causes that led to this: political support (from agriculture officials), ability to solve prevalent farmers' needs, economic and environmental factors and an early implementation of effective regulations. The political willingness to study this new technology and crops as well as the recruitment of sound professionals and scientists to perform the task was crucial. These professionals, with very diverse backgrounds, created the necessary regulatory framework to work with these new crops. Farmers played a decisive role, as adopting this new technology solved some of their agronomic problems, helped them perform more sustainable agronomic practices and provided economic benefits. Nonetheless, all these advancements had not been possible without a rational, science-based and flexible regulatory framework that would make sure that the GM crops were safe for food, feed and processing.

  17. Drivers of nitrogen dynamics in ecologically based agriculture revealed by long-term, high-frequency field measurements.

    PubMed

    Finney, Denise M; Eckert, Sara E; Kaye, Jason P

    2015-12-01

    Nitrogen (N) loss from agriculture impacts ecosystems worldwide. One strategy to mitigate these losses, ecologically based nutrient management (ENM), seeks to recouple carbon (C) and N cycles to reduce environmental losses and supply N to cash crops. However, our capacity to apply ENM is limited by a lack of field-based high-resolution data on N dynamics in actual production contexts. We used data from a five-year study of organic cropping systems to investigate soil inorganic N (SIN) variability and nitrate (NO3-) leaching in ENM. Four production systems initiated in 2007 and 2008 in central Pennsylvania varied in crop rotation, timing and intensity of tillage, inclusion of fallow periods, and N inputs. Extractable SIN was measured fortnightly from March through November throughout the experiment, and NO3- N concentration below the rooting zone was sampled with lysimeters during the first year of the 2008 start. We used recursive partitioning models to assess the importance of management and environmental factors to SIN variability and NO3- leaching and identify interactions between influential variables. Air temperature and tillage were the most important drivers of SIN across systems. The highest SIN concentrations occurred when the average air temperature three weeks prior to measurement was above 21 degrees C. Above this temperature and within 109 days of moldboard plowing, average SIN concentrations were 22.1 mg N/kg soil; 109 days or more past plowing average SIN dropped to 7.7 mg N/kg soil. Other drivers of SIN dynamics were N available from manure and cover crops. Highest average leachate NO3- N concentrations (15.2 ppm) occurred in fall and winter when SIN was above 4.9 mg/kg six weeks prior to leachate collection. Late season tillage operations leading to elevated SIN and leachate NO3- N concentrations were a strategy to reduce weeds while meeting consumer demand for organic products. Thus, while tillage that incorporates organic N inputs preceding cash

  18. Drivers of nitrogen dynamics in ecologically based agriculture revealed by long-term, high-frequency field measurements.

    PubMed

    Finney, Denise M; Eckert, Sara E; Kaye, Jason P

    2015-12-01

    Nitrogen (N) loss from agriculture impacts ecosystems worldwide. One strategy to mitigate these losses, ecologically based nutrient management (ENM), seeks to recouple carbon (C) and N cycles to reduce environmental losses and supply N to cash crops. However, our capacity to apply ENM is limited by a lack of field-based high-resolution data on N dynamics in actual production contexts. We used data from a five-year study of organic cropping systems to investigate soil inorganic N (SIN) variability and nitrate (NO3-) leaching in ENM. Four production systems initiated in 2007 and 2008 in central Pennsylvania varied in crop rotation, timing and intensity of tillage, inclusion of fallow periods, and N inputs. Extractable SIN was measured fortnightly from March through November throughout the experiment, and NO3- N concentration below the rooting zone was sampled with lysimeters during the first year of the 2008 start. We used recursive partitioning models to assess the importance of management and environmental factors to SIN variability and NO3- leaching and identify interactions between influential variables. Air temperature and tillage were the most important drivers of SIN across systems. The highest SIN concentrations occurred when the average air temperature three weeks prior to measurement was above 21 degrees C. Above this temperature and within 109 days of moldboard plowing, average SIN concentrations were 22.1 mg N/kg soil; 109 days or more past plowing average SIN dropped to 7.7 mg N/kg soil. Other drivers of SIN dynamics were N available from manure and cover crops. Highest average leachate NO3- N concentrations (15.2 ppm) occurred in fall and winter when SIN was above 4.9 mg/kg six weeks prior to leachate collection. Late season tillage operations leading to elevated SIN and leachate NO3- N concentrations were a strategy to reduce weeds while meeting consumer demand for organic products. Thus, while tillage that incorporates organic N inputs preceding cash

  19. Field evaluation of willow under short rotation coppice for phytomanagement of metal-polluted agricultural soils.

    PubMed

    Van Slycken, Stijn; Witters, Nele; Meiresonne, Linda; Meers, Erik; Ruttens, Ann; Van Peteghem, Pierre; Weyens, Nele; Tack, Filip M G; Vangronsveld, Jaco

    2013-01-01

    Short rotation coppice (SRC) of willow and poplar might be a promising phytoremediation option since it uses fast growing, high biomass producing tree species with often a sufficient metal uptake. This study evaluates growth, metal uptake and extraction potentials of eight willow clones (Belders, Belgisch Rood, Christina, Inger, Jorr, Loden, Tora and Zwarte Driebast) on a metal-contaminated agricultural soil, with total cadmium (Cd) and zinc (Zn) concentrations of 6.5 +/- 0.8 and 377 +/- 69 mg kg(-1) soil, respectively. Although, during the first cycle, on average generally low productivity levels (3.7 ton DM (dry matter) ha(-1) y(-1)) were obtained on this sandy soil, certain clones exhibited quite acceptable productivity levels (e.g. Zwarte Driebast 12.5 ton DM ha(-1) y(-1)). Even at low biomass productivity levels, SRC of willow showed promising removal potentials of 72 g Cd and 2.0 kg Zn ha(-1) y(-1), which is much higher than e.g. energy maize or rapeseed grown on the same soil Cd and Zn removal can be increased by 40% if leaves are harvested as well. Nevertheless, nowadays the wood price remains the most critical factor in order to implement SRC as an acceptable, economically feasible alternative crop on metal-contaminated agricultural soils.

  20. Influence of a riparian wetland on nitrate and herbicides exported from an agricultural field.

    PubMed

    Angier, Jonathan T; McCarty, Gregory W; Rice, Clifford P; Bialek, Krystyna

    2002-07-17

    Agrochemicals are a major source of nonpoint pollution. Forested corridors along stream channels (riparian zones) are thought to be potential sites for removal of agricultural contaminants from ground and surface waters. First-order riparian wetlands are reputed to be especially effective at groundwater remediation. The study site is a fairly typical (for eastern Maryland) small, first-order stream in an agricultural watershed. Preferential flow supplies most of the stream water within the riparian headwater wetland. This upstream area also contains the highest average stream N and pesticide loads in the entire first-order riparian system. Zones of active groundwater emergence onto the surface display high concentrations of nitrate throughout the soil profile and in the exfiltrating water, whereas inactive areas (where there is no visible upwelling) show rapid attenuation of nitrate with decreasing depths. Atrazine degradation products appear to penetrate more readily through the most active upwelling zones, and there is a correlation between zones of high nitrate and high atrazine metabolite levels. Deethylatrazine/atrazine ratios (DAR) seem to indicate that stream flow is dominated by ground water and that much of the ground water may have reached the stream via preferential flow. Remediative processes appear to be very complex, heterogeneous, and variable in these systems, so additional research is needed before effective formulation and application of riparian zone initiatives and guidelines can be accomplished.

  1. The National Airborne Field Experiment 2006 (NAFE'06) Dataset

    NASA Astrophysics Data System (ADS)

    Panciera, R.; Walker, J. P.; Merlin, O.; Kalma, J.; Kim, E.; Hacker, J.

    2007-05-01

    Remote sensing technology has a huge potential for improving hydrologic prediction through soil moisture measurement. This is particularly so given that the first dedicated soil moisture satellite, the Soil Moisture and Ocean Salinity (SMOS) mission, is to be launched in late 2007. However, targeted field experiments must be undertaken and the data analysed prior to launch so that immediate use can be made of this data when it becomes available. Consequently, the National Airborne Field Experiment was conducted in the Murrumbidge catchment, located in south-eastern Australia, during November 2006 (NAFE'06). The intent of this experiment was to provide simulated SMOS observations supported by ground measurement of soil moisture and other relevant ground data for i) development of the SMOS retrieval algorithms, ii) developing approaches for downscaling the low resolution data from SMOS to 1km resolution, and iii) testing its assimilation into land surface models for root zone soil moisture retrieval. This paper describes the NAFE'06 data set. The SMOS-type data were collected using a Polarimetric L-band Multi-beam Radiometer (PLMR), together with supporting instruments (thermal imager, tri-spectral scanner, lidar and digital photograph). Flights included 1km resolution passive microwave data across the main 40km x 55km Yanco study area every 2-3 days, for simulation of a SMOS pixel, verification of downscaling techniques and assimilation, and a transect across the area twice a week to provide both 500m multi-angular passive microwave data for SMOS algorithm development and 50m resolution passive microwave data for algorithm verification. This was done alternatively at 6am and 6pm, so that both SMOS overpass times could be tested. A medium resolution flight (250m for PLMR) was also performed once per week across an irrigated portion of the Yanco study area to study the effect of standing water on microwave emission. The NDVI, lidar and aerial photo supporting

  2. A field-scale study of cadmium phytoremediation in a contaminated agricultural soil at Mae Sot District, Tak Province, Thailand: (1) Determination of Cd-hyperaccumulating plants.

    PubMed

    Khaokaew, Saengdao; Landrot, Gautier

    2015-11-01

    The cadmium (Cd) phytoremediation capabilities of Gynura pseudochina, Chromolaena odorata, Conyza sumatrensis, Crassocephalum crepidioides and Nicotiana tabacum were determined by conducting in-situ experiments in a highly Cd-contaminated agricultural field at Mae Sot District, Tak Province, Thailand. Most of these five plant species, which are commonly found in Thailand, previously demonstrated Cd-hyperaccumulating capacities under greenhouse conditions. This study represented an important initial step in determining if any of these plants could, under field-conditions, effectively remove Cd from the Mae Sot contaminated fields, which represent a health threat to thousands of local villagers. All plant species had at least a 95% survival rate on the final harvest day. Additionally, all plant species, except C. odorata, could hyperaccumulate the extractable Cd amounts present in the soil, based on their associated Bioaccumulation Factor (BAF), Translocation Factor (TF), and background Vegetation Factor (VF). Therefore, the four Cd-hyperaccumulating plant species identified in this study may successfully treat a majority of contaminated fields at Mae Sot, as it was previously reported that Cd amounts present in a number of these soils were mostly available.

  3. Vocational Agriculture I Basic Core. Section C--Supervised Experience Programs.

    ERIC Educational Resources Information Center

    Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This curriculum guide contains five units teaching preservice vocational teachers to conduct supervised experience programs. Each unit contains an objective (e.g., "After completing this unit, the student should be able to choose and plan supervised occupational experience programs"); specific objectives (e.g., "State reasons for having a…

  4. Phosphorus Transport at the Field Scale by Monitoring Groundwater and Interflow Discharge in Hydrologically Sensitive Areas in Agricultural Fields

    NASA Astrophysics Data System (ADS)

    Flores-Lopez, F.; Geohring, L.; Steenhuis, T.

    2004-05-01

    Quantification of nonpoint source of phosphorus losses through agricultural land is important because hydrologically active areas can significantly affect water quality. In this study we examined phosphorus concentration and phosphorus losses from hydrologically sensitive areas and upland areas located in valley soils in the Cannosville basin in Catskill Mountains. Phosphorus concentrations as low as 0.01 - 0.02 mg/L in water increase the algael bloom in lakes and reservoirs and the Cannosville basin is currently restricted to 0.02mg/L. We measured grab surface water samples taken along the creeks to study the phosphorus concentration in the sub-superficial runoff that drains water from the surrounding hills. Also we installed two different transects of piezometers, one line upstream and one line downstream, to study the role of the groundwater component and its effect in the hydrologically sensitive areas. We generally found low phosphorus concentration in the grab surface water samples and the groundwater samples taken in the piezometers. Sampling during the highest creek flow has resulted in the highest concentrations, generally near 0.05 mg/L of dissolved reactive phosphorus. These concentrations were slightly higher than the concentrations in most of the wells, which were around 0.03 mg/L. Sampling is ongoing to determine the effects snow melt contributions. Results will be presented to show the seasonal effects of phosphorus in the hydrologically sensitive areas.

  5. Interdependence of soil and agricultural practice in a two - year phytoremediation in situ experiment

    NASA Astrophysics Data System (ADS)

    Nwaichi, Eucharia; Onyeike, Eugene; Frac, Magdalena; Iwo, Godknows

    2016-04-01

    A two - year plant - based soil clean - up was carried out at a crude oil spill agricultural site in a Niger Delta community in Nigeria to access further clean - up potentials of Cymbopogon citratus. Applied diagnostic ratios identified mixed petrogenic and pyrogenic sources as the main contributors of PAHs. Up to 90.8% sequestration was obtained for carcinogenic PAHs especially Benz (a) pyrene in a 2 - phase manner. A community level approach for assessing patterns of sole carbon source utilization by mixed microbial samples was employed to differentiate spatial and temporal changes in the soil microbial communities. In relation to pollution, soil conditioning notably decreased the lag times and showed mixed effects for colour development rates, maximum absorbance and the overall community pattern. For rate and utilization of different carbon substrates in BIOLOG wells, after day 3, in comparison to control soil communities, contamination with hydrocarbons and associated types increased amines and amides consumption. Consumption of carbohydrates in all polluted and unamended regimes decreased markedlyin comparison to those cultivated with C. citratus. We found a direct relationship between cellulose breakdown, measurable with B-glucosidase activity, organic matter content and CO2 realease within all soils in the present study. Organic amendment rendered most studied contaminants unavailable for uptake in preference to inorganic fertilizer in both study years. Generally, phytoremediation improved significantly the microbial community activity and thus would promote ecosystem restoration in relation to most patronised techniques. Supplementation with required nutrients, in a long - term design would present many ecological benefits. Keywords: Agricultural soils; Recovery; Hydrocarbon pollution; Ecology; Management practice.

  6. Towards the Development of a Smart Flying Sensor: Illustration in the Field of Precision Agriculture.

    PubMed

    Hernandez, Andres; Murcia, Harold; Copot, Cosmin; De Keyser, Robin

    2015-01-01

    Sensing is an important element to quantify productivity, product quality and to make decisions. Applications, such as mapping, surveillance, exploration and precision agriculture, require a reliable platform for remote sensing. This paper presents the first steps towards the development of a smart flying sensor based on an unmanned aerial vehicle (UAV). The concept of smart remote sensing is illustrated and its performance tested for the task of mapping the volume of grain inside a trailer during forage harvesting. Novelty lies in: (1) the development of a position-estimation method with time delay compensation based on inertial measurement unit (IMU) sensors and image processing; (2) a method to build a 3D map using information obtained from a regular camera; and (3) the design and implementation of a path-following control algorithm using model predictive control (MPC). Experimental results on a lab-scale system validate the effectiveness of the proposed methodology. PMID:26184205

  7. Towards the Development of a Smart Flying Sensor: Illustration in the Field of Precision Agriculture

    PubMed Central

    Hernandez, Andres; Murcia, Harold; Copot, Cosmin; De Keyser, Robin

    2015-01-01

    Sensing is an important element to quantify productivity, product quality and to make decisions. Applications, such as mapping, surveillance, exploration and precision agriculture, require a reliable platform for remote sensing. This paper presents the first steps towards the development of a smart flying sensor based on an unmanned aerial vehicle (UAV). The concept of smart remote sensing is illustrated and its performance tested for the task of mapping the volume of grain inside a trailer during forage harvesting. Novelty lies in: (1) the development of a position-estimation method with time delay compensation based on inertial measurement unit (IMU) sensors and image processing; (2) a method to build a 3D map using information obtained from a regular camera; and (3) the design and implementation of a path-following control algorithm using model predictive control (MPC). Experimental results on a lab-scale system validate the effectiveness of the proposed methodology. PMID:26184205

  8. A persistent scatterer interpolation for retrieving accurate ground deformation over InSAR-decorrelated agricultural fields

    NASA Astrophysics Data System (ADS)

    Chen, Jingyi; Zebker, Howard A.; Knight, Rosemary

    2015-11-01

    Interferometric synthetic aperture radar (InSAR) is a radar remote sensing technique for measuring surface deformation to millimeter-level accuracy at meter-scale resolution. Obtaining accurate deformation measurements in agricultural regions is difficult because the signal is often decorrelated due to vegetation growth. We present here a new algorithm for retrieving InSAR deformation measurements over areas with severe vegetation decorrelation using adaptive phase interpolation between persistent scatterer (PS) pixels, those points at which surface scattering properties do not change much over time and thus decorrelation artifacts are minimal. We apply this algorithm to L-band ALOS interferograms acquired over the San Luis Valley, Colorado, and the Tulare Basin, California. In both areas, the pumping of groundwater for irrigation results in deformation of the land that can be detected using InSAR. We show that the PS-based algorithm can significantly reduce the artifacts due to vegetation decorrelation while preserving the deformation signature.

  9. Towards the Development of a Smart Flying Sensor: Illustration in the Field of Precision Agriculture.

    PubMed

    Hernandez, Andres; Murcia, Harold; Copot, Cosmin; De Keyser, Robin

    2015-07-10

    Sensing is an important element to quantify productivity, product quality and to make decisions. Applications, such as mapping, surveillance, exploration and precision agriculture, require a reliable platform for remote sensing. This paper presents the first steps towards the development of a smart flying sensor based on an unmanned aerial vehicle (UAV). The concept of smart remote sensing is illustrated and its performance tested for the task of mapping the volume of grain inside a trailer during forage harvesting. Novelty lies in: (1) the development of a position-estimation method with time delay compensation based on inertial measurement unit (IMU) sensors and image processing; (2) a method to build a 3D map using information obtained from a regular camera; and (3) the design and implementation of a path-following control algorithm using model predictive control (MPC). Experimental results on a lab-scale system validate the effectiveness of the proposed methodology.

  10. Natural establishment of woody species on abandoned agricultural fields in the lower Mississippi Valley: first- and second-year results

    USGS Publications Warehouse

    Allen, J.A.; McCoy, J.W.; Keeland, B.D.

    1998-01-01

    The natural establishment of woody seedlings on abandoned agricultural fields was investigated at sites in Louisiana and Mississippi. Series of disked and undisked plots originating at forest edges and oriented in cardinal directions were established on fields at each site. During the firest 2 years, seedling recruitment was dominated by sweetgum, sugarberry, and elms at both sites. Seedling establishment was strongly affected by direction from mature forest and disking, and to a slightly lesser degree by distance from mature forest. Slightly under half of the variation in seedling numbers per plot was explained by the effects of direction, distance, and disking, indicating that other factors also may play an important role in seedling recruitment.

  11. Investigating summer flow paths in a Dutch agricultural field using high frequency direct measurements

    NASA Astrophysics Data System (ADS)

    Delsman, J. R.; Waterloo, M. J.; Groen, M. M. A.; Groen, J.; Stuyfzand, P. J.

    2014-11-01

    The search for management strategies to cope with projected water scarcity and water quality deterioration calls for a better understanding of the complex interaction between groundwater and surface water in agricultural catchments. We separately measured flow routes to tile drains and an agricultural ditch in a deep polder in the coastal region of the Netherlands, characterized by exfiltration of brackish regional groundwater flow and intake of diverted river water for irrigation and water quality improvement purposes. We simultaneously measured discharge, electrical conductivity and temperature of these separate flow routes at hourly frequencies, disclosing the complex and time-varying patterns and origins of tile drain and ditch exfiltration. Tile drainage could be characterized as a shallow flow system, showing a non-linear response to groundwater level changes. Tile drainage was fed primarily by meteoric water, but still transported the majority (80%) of groundwater-derived salt to surface water. In contrast, deep brackish groundwater exfiltrating directly in the ditch responded linearly to groundwater level variations and is part of a regional groundwater flow system. We could explain the observed salinity of exfiltrating drain and ditch water from the interaction between the fast-responding pressure distribution in the subsurface that determined groundwater flow paths (wave celerity), and the slow-responding groundwater salinity distribution (water velocity). We found water demand for maintaining water levels and diluting salinity through flushing to greatly exceed the actual sprinkling demand. Counterintuitively, flushing demand was found to be largest during precipitation events, suggesting the possibility of water savings by operational flushing control.

  12. An Oceanographic Decision Support System for Scientific Field Experiments

    NASA Astrophysics Data System (ADS)

    Maughan, T.; Das, J.; McCann, M. P.; Rajan, K.

    2011-12-01

    Thom Maughan, Jnaneshwar Das, Mike McCann, Danelle Cline, Mike Godin, Fred Bahr, Kevin Gomes, Tom O'Reilly, Frederic Py, Monique Messie, John Ryan, Francisco Chavez, Jim Bellingham, Maria Fox, Kanna Rajan Monterey Bay Aquarium Research Institute Moss Lading, California, United States Many of the coastal ocean processes we wish to observe in order to characterize marine ecosystems have large spatial extant (tens of square km) and are dynamic moving kilometers in a day with biological processes spanning anywhere from minutes to days. Some like harmful algal blooms generate toxins which can significantly impact human health and coastal economies. In order to obtain a viable understanding of the biogeochemical processes which define their dynamics and ecology, it is necessary to persistently observe, track and sample within and near the dynamic fields using augmented methods of observation such as autonomous platforms like AUVs, gliders and surface craft. Field experiments to plan, execute and manage such multitude of assets are challenging. To alleviate this problem the autonomous systems group with its collaborators at MBARI and USC designed, built and fielded a prototype Oceanographic Decision Support System (ODSS) that provides situational awareness and a single portal to visualize and plan deployments for the large scale October 2010 CANON field program as well as a series of 2 week field programs in 2011. The field programs were conducted in Monterey Bay, a known 'red tide' incubator, and varied from as many as twenty autonomous platforms, four ships and 2 manned airplanes to coordinated AUV operations, drifters and a single ship. The ODSS web-based portal was used to assimilate information from a collection of sources at sea, including AUVs, moorings, radar data as well as remote sensing products generated by partner organizations to provide a synthesis of views useful to predict the movement of a chlorophyll patch in the confines of the northern Monterey Bay

  13. Assessment of soil redistribution rates by (137)Cs and (210)Pbex in a typical Malagasy agricultural field.

    PubMed

    Rabesiranana, N; Rasolonirina, M; Solonjara, A F; Ravoson, H N; Raoelina Andriambololona; Mabit, L

    2016-02-01

    Soil degradation processes affect more than one-third of the Malagasy territory and are considered as the major environmental threat impacting the natural resources of the island. This innovative study reports about a pioneer test and use of radio-isotopic techniques (i.e. Cs-137 and Pb-210ex) under Madagascar agroclimatic condition to evaluate soil erosion magnitude. This preliminary investigation has been conducted in a small agricultural field situated in the eastern central highland of Madagascar, 40 km East from Antananarivo. Both anthropogenic Cs-137 and geogenic Pb-210 soil tracers provided similar results highlighting soil erosion rates reaching locally 18 t ha(-1) yr(-1,) a level almost two times higher than the sustainable soil loss rate under Madagascar agroclimatic condition. The sediment delivery ratio established with both radiotracers was above 80% indicating that most of the mobilized sediment exits the field. Assessing soil erosion rate through fallout radionuclides in Madagascar is a first step towards an efficient land and water resource management policy to optimise the effectiveness of future agricultural soil conservation practices. PMID:26691498

  14. Assessment of soil redistribution rates by (137)Cs and (210)Pbex in a typical Malagasy agricultural field.

    PubMed

    Rabesiranana, N; Rasolonirina, M; Solonjara, A F; Ravoson, H N; Raoelina Andriambololona; Mabit, L

    2016-02-01

    Soil degradation processes affect more than one-third of the Malagasy territory and are considered as the major environmental threat impacting the natural resources of the island. This innovative study reports about a pioneer test and use of radio-isotopic techniques (i.e. Cs-137 and Pb-210ex) under Madagascar agroclimatic condition to evaluate soil erosion magnitude. This preliminary investigation has been conducted in a small agricultural field situated in the eastern central highland of Madagascar, 40 km East from Antananarivo. Both anthropogenic Cs-137 and geogenic Pb-210 soil tracers provided similar results highlighting soil erosion rates reaching locally 18 t ha(-1) yr(-1,) a level almost two times higher than the sustainable soil loss rate under Madagascar agroclimatic condition. The sediment delivery ratio established with both radiotracers was above 80% indicating that most of the mobilized sediment exits the field. Assessing soil erosion rate through fallout radionuclides in Madagascar is a first step towards an efficient land and water resource management policy to optimise the effectiveness of future agricultural soil conservation practices.

  15. Spectral properties of agricultural crops and soils measured from space, aerial, field, and laboratory sensors

    NASA Technical Reports Server (NTRS)

    Bauer, M. E. (Principal Investigator); Vanderbilt, V. C.; Robinson, B. F.; Daughtry, C. S. T.

    1981-01-01

    Investigations of the multispectral reflectance characteristics of crops and soils as measured from laboratory, field, aerial, and satellite sensor systems are reviewed. The relationships of important biological and physical characteristics to the spectral properties of crops and soils are addressed.

  16. Waterfowl density on agricultural fields managed to retain water in winter

    USGS Publications Warehouse

    Twedt, D.J.; Nelms, C.O.

    1999-01-01

    Managed water on private and public land provides habitat for wintering waterfowl in the Mississippi Valley, where flood control projects have reduced the area of natural flooding. We compared waterfowl densities on rice, soybean, and moist-soil fields under cooperative agreements to retain water from 1 November through 28 February in Arkansas and Mississippi and assessed temporal changes in waterfowl density during winter in 1991-1992 and 1992-1993. Fields flooded earlier in Arkansas, but retained water later in Mississippi. Over winter, waterfowl densities decreased in Arkansas and increased in Mississippi. Densities of waterfowl, including mallard (Anas platyrhynchos), the most abundant species observed, were greatest on moist-soil fields. However, soybean fields had the greatest densities of northern shoveler (Spatula clypeata).

  17. Enhancement of the Initial Growth Rate of Agricultural Plants by Using Static Magnetic Fields.

    PubMed

    Kim, Seung C; Mason, Alex; Im, Wooseok

    2016-01-01

    Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing seeds of Garden Balsam (Impatiens balsamina), Mizuna (Brassica rapa var. japonica), Komatsuna (Brassica rapa var. perviridis), and Mescluns (Lepidium sativum). We applied magnets under the culture dish. During the 4 days of application, we observed that the stem and root length increased. The group subjected to magnetic field treatment (n = 10) showed a 1.4 times faster rate of growth compared with the control group (n = 11) in a total of 8 days (p <0.0005). This rate is 20% higher than that reported in previous studies. The tubulin complex lines did not have connecting points, but connecting points occur upon the application of magnets. This shows complete difference from the control, which means abnormal arrangements. However, the exact cause remains unclear. These results of growth enhancement of applying magnets suggest that it is possible to enhance the growth rate, increase productivity, or control the speed of germination of plants by applying static magnetic fields. Also, magnetic fields can cause physiological changes in plant cells and can induce growth. Therefore, stimulation with a magnetic field can have possible effects that are similar to those of chemical fertilizers, which means that the use of fertilizers can be avoided.

  18. Enhancement of the Initial Growth Rate of Agricultural Plants by Using Static Magnetic Fields.

    PubMed

    Kim, Seung C; Mason, Alex; Im, Wooseok

    2016-01-01

    Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing seeds of Garden Balsam (Impatiens balsamina), Mizuna (Brassica rapa var. japonica), Komatsuna (Brassica rapa var. perviridis), and Mescluns (Lepidium sativum). We applied magnets under the culture dish. During the 4 days of application, we observed that the stem and root length increased. The group subjected to magnetic field treatment (n = 10) showed a 1.4 times faster rate of growth compared with the control group (n = 11) in a total of 8 days (p <0.0005). This rate is 20% higher than that reported in previous studies. The tubulin complex lines did not have connecting points, but connecting points occur upon the application of magnets. This shows complete difference from the control, which means abnormal arrangements. However, the exact cause remains unclear. These results of growth enhancement of applying magnets suggest that it is possible to enhance the growth rate, increase productivity, or control the speed of germination of plants by applying static magnetic fields. Also, magnetic fields can cause physiological changes in plant cells and can induce growth. Therefore, stimulation with a magnetic field can have possible effects that are similar to those of chemical fertilizers, which means that the use of fertilizers can be avoided. PMID:27500712

  19. Field experiments of nonlocal sediment transport on a steep hillslope

    NASA Astrophysics Data System (ADS)

    DiBiase, R.; Booth, A. M.; Ganti, V.; Scheingross, J. S.; Lamb, M. P.

    2014-12-01

    Steep rocky hillslopes dominate the areal extent of rapidly uplifting mountain ranges, and pose a significant hazard to encroaching population centers. Existing models for hillslope sediment transport developed for soil-mantled landscapes are poorly suited to explain the evolution of steep hillslopes characterized by: (1) intermittent or patchy soil cover, (2) slopes that exceed the angle of repose, and (3) transport events that often involve long travel distances. Recently, nonlocal formulations of hillslope sediment transport laws that account for long travel distances have been proposed to overcome the limitations of traditional continuum-based models. However, their application to natural landscapes has been limited owing to few field constraints on key parameters, and computational difficulties expanding the framework to two-dimensions. To address this knowledge gap, we performed a series of field experiments on natural hillslopes to inform a simple particle-based model of hillslope sediment transport. We compiled the distribution of average velocity and transport distance for over 300 stones ranging in diameter from 2-10 cm using a video camera and laser range-finder. To characterize surface roughness, we used a tripod-based laser scanner to generate a 1 cm-resolution digital elevation model of each 30 m long hillslope. We find that hillslope travel distance follows a heavy-tailed distribution that varies systematically with the ratio of particle diameter to roughness height, in general agreement to published laboratory experiments. Mean particle velocity ranges from 1-3 m/s and scales weakly with distance traveled. Our modeling exercise reveals three key effects that should be included in any treatment of steep hillslope evolution: (1) there is a strong grain-size and surface roughness dependence on sediment transport distance, (2) sediment storage on slopes steeper than the angle of repose is possible due to vegetation or topographic roughness, and (3

  20. Status of SRNL radiological field lysimeter experiment-Year 1

    SciTech Connect

    Kaplan, D.; Roberts, K.; Bagwell, L.

    2013-10-01

    The Savannah River National Laboratory (SRNL) Radiological Field Lysimeter Experiment is a one-of-a-kind field facility designed to study radionuclide geochemical processes at a larger spatial scale (from grams to tens of kilograms sediment) and temporal scale (from months to 10 years) than is readily afforded through laboratory studies. The lysimeter facility is intended to capture the natural heterogeneity of moisture and temperature regimes in the vadose zone, the unsaturated subsurface region between the surface soil and the underlying aquifer. The 48 lysimeter columns, which contain various radionuclides (and stable iodine), were opened to rainfall infiltration on July 5, 2012. The objective of this report is to provide a status of the lysimeter facility operations and to compile data collected during FY13, including leachate volume, rainfall, and soil moisture and temperature in situ probe data. Radiological leachate data are not presented in this document but will be the subject of a separate document.1 Leachate samples were collected quarterly and shipped to Clemson University for radiological analyses. Rainfall, leachate volume, moisture and temperature probe data were collected continuously. During operations of the facility this year, there were four safety or technical concerns that required additional maintenance: 1) radioactivity was detected in one of the overflow bottles (captured water collected from the secondary containment that does not come in contact with the radiological source material); 2) rainwater accumulated within the sample-bottle storage sheds; 3) overflow containers collected more liquid than anticipated; and 4) significant spider infestation occurred in the sample-bottle storage sheds. To address the first three concerns, each of the lysimeter columns was re-plumbed to improve and to minimize the number of joint unions. To address the fourth concern regarding spiders, new sample-bottle water sheds were purchased and a pest control

  1. Potentials of RapidEye time series for improved classification of crop rotations in heterogeneous agricultural landscapes: experiences from irrigation systems in Central Asia

    NASA Astrophysics Data System (ADS)

    Conrad, Christopher; Machwitz, Miriam; Schorcht, Gunther; Löw, Fabian; Fritsch, Sebastian; Dech, Stefan

    2011-11-01

    In Central Asia, more than eight Million ha of agricultural land are under irrigation. But severe degradation problems and unreliable water distribution have caused declining yields during the past decades. Reliable and area-wide information about crops can be seen as important step to elaborate options for sustainable land and water management. Experiences from RapidEye classifications of crop in Central Asia are exemplarily shown during a classification of eight crop classes including three rotations with winter wheat, cotton, rice, and fallow land in the Khorezm region of Uzbekistan covering 230,000 ha of irrigated land. A random forest generated by using 1215 field samples was applied to multitemporal RapidEye data acquired during the vegetation period 2010. But RapidEye coverage varied and did not allow for generating temporally consistent mosaics covering the entire region. To classify all 55,188 agricultural parcels in the region three classification zones were classified separately. The zoning allowed for including at least three observation periods into classification. Overall accuracy exceeded 85 % for all classification zones. Highest accuracies of 87.4 % were achieved by including five spatiotemporal composites of RapidEye. Class-wise accuracy assessments showed the usefulness of selecting time steps which represent relevant phenological phases of the vegetation period. The presented approach can support regional crop inventory. Accurate classification results in early stages of the cropping season permit recalculation of crop water demands and reallocation of irrigation water. The high temporal and spatial resolution of RapidEye can be concluded highly beneficial for agricultural land use classifications in entire Central Asia.

  2. Hydrological and erosion processes in terraced agricultural fields: observations from a wet Mediterranean region in northern Portugal

    NASA Astrophysics Data System (ADS)

    Nunes, João Pedro; Bernard-Jannin, Léonard; Rodriguez-Blanco, María Luz; Marisa Santos, Juliana; Oliveira Alves Coelho, Celeste; Keizer, Jan Jacob

    2015-04-01

    Traditional agriculture in the mountainous humid regions of the northwestern Iberian peninsula has relied on terraces for soil retention. In the last decades, a strong afforestation (in many cases with commercial species) has led to the appearance of large forest areas coexisting with traditional agricultural landscapes. Soil erosion research in this region has therefore focused on the impact of forest management practices and associated disturbances such as wildfires. However, there has been little research on the impacts of traditional terracing practices on erosion, and therefore it has been difficult to connect forest research with the wider issue of sediment connectivity in this complex agroforestry landscape. This work tried to address this research gap by monitoring an agricultural terrace in the Caramulo mountains, northern Portugal, during two years. The field site is located in a humid Mediterranean climate region, with c. 1500 mm/y rainfall, overlaying granite bedrock; agricultural practices are a traditional rotation between winter pasture and summer (irrigated) corn cultivation. During this period, the soil properties of the terrace were characterized, and there was a continuous monitoring of rainfall, soil moisture and surface runoff at the outlet, as well as 1 or 2-weekly collections of runoff to measure sediment yield. Occasional measurements of vegetation cover and erosion features (rills) within the plot were also made. Preliminary results indicate that runoff generation occurred mostly due to saturation-excess, possibly linked with the accumulation of groundwater in the lower layers of the soil. After one of the largest events, there was a clear inflow of runoff from outside the terrace, through either the irrigation network linking all terraces or by resurfacing of groundwater. Sediment yield was linked with runoff, but sediment concentration was linked with vegetation cover and was highest during the early stages of pasture growth. However

  3. Long-term monitoring of nitrate-N transport to drainage from three agricultural clayey till fields

    NASA Astrophysics Data System (ADS)

    Ernstsen, V.; Olsen, P.; Rosenbom, A. E.

    2015-01-01

    The application of nitrogen (N) fertilisers to crops grown on tile-drained fields is necessary to sustain most modern crop production, but poses a risk to the aquatic environment since tile drains facilitate rapid transport pathways with no significant reduction in nitrate. To maintain the water quality of the aquatic environment and the provision of food from highly efficient agriculture in line with the EU's Water Framework Directive and Nitrates Directive, field-scale knowledge is imperative if there is to be differentiated N-regulation in future. This study describes nitrate-N leaching to drainage based on coherent monitoring of nitrate-N concentrations, the climate, the groundwater table and crop-specific parameters obtained over eleven years (2001-2011) at three subsurface-drained clayey till fields (1.3-2.3 ha). The monitoring results showed significant field differences in nitrate-N transport to drainage. Not only were these caused by periods of bare soil after short-season crops and N-fixing crops (pea), which have been shown to generate high nitrate-N concentrations in drainage, but by the hydrogeological field conditions that were shown to be the controlling factor of nitrate-N transport to drainage. The fields had the following characteristics: (A) the lowest mass transport (13 kg N ha-1) and fertiliser input had short-term and low-intensity drainage with the highest nitrate-N concentrations detected, representing 40% of net precipitation (226 mm) combined with low air temperatures, (B) the medium mass transport (14 kg N ha-1) had medium-term and medium-intensity drainage, representing 42% of net precipitation (471 mm) combined with periods of both low and higher air temperatures, (C) the highest mass transport (19 kg N ha-1) had long-term drainage, representing 68% of net precipitation (617 mm), but had the highest potential for in-situ soil denitrification and post-treatment (e.g. constructed wetlands) due to long periods with both high water

  4. Idaho field experiment 1981. Volume 2: measurement data

    SciTech Connect

    Start, G E; Sagendorf, J F; Ackermann, G R; Cate, J H; Hukari, N F; Dickson, C R

    1984-04-01

    The 1981 Idaho Field Experiment was conducted in southeastern Idaho over the upper Snake River Plain. Nine test-day case studies were conducted between July 15 and 30, 1981. Releases of SF/sub 6/ gaseous tracer were made for 8-hour periods from 46m above ground. Tracer was sampled hourly, for 12 sequential hours, at about 100 locations within an area 24km square. Also, a single total integrated sample of about 30 hours duration was collected at approximately 100 sites within an area 48 by 72km square (using 6km spacings). Extensive tower profiles of meteorology at the release point were collected. RAWINSONDES, RABALS and PIBALS were collected at 3 to 5 sites. Horizontal, low-altitude winds were monitored using the INEL MESONET. SF/sub 6/ tracer plume releases were marked with co-located oil fog releases and bi-hourly sequential launches of tetroon pairs. Aerial LIDAR observations of the oil fog plume and airborne samples of SF/sub 6/ were collected. High altitude aerial photographs of daytime plumes were collected. Volume II lists the data in tabular form or cites the special supplemental reports by other participating contractors. While the primary user file and the data archive are maintained on 9 track/1600 cpi magnetic tapes, listings of the individual values are provided for the user who either cannot utilize the tapes or wishes to preview the data. The accuracies and quality of these data are described.

  5. Test plan for FY-94 digface characterization field experiments

    SciTech Connect

    Josten, N.E.; Roybal, L.G.

    1994-08-01

    The digface characterization concept has been under development at the Idaho National Engineering Laboratory (INEL) since fiscal year (FY) 1992 through the support of the Buried Waste Integrated Demonstration Program. A digface characterization system conducts continuous subsurface characterization simultaneously with retrieval of hazardous and radioactive waste from buried waste sites. The system deploys multiple sensors at the retrieval operation digface and collects data that provide a basis for detecting, locating, and classifying buried materials and hazardous conditions before they are disturbed by the retrieval equipment. This test plan describes ongoing efforts to test the digface characterization concept at the INEL`s Cold Test Pit using a simplified prototype deployment apparatus and off-the-shelf sensors. FY-94 field experiments will explore problems in object detection and classification. Detection and classification of objects are fundamental to three of the four primary functions of digface characterization during overburden removal. This test plan establishes procedures for collecting and validating the digface characterization data sets. Analysis of these data will focus on testing and further developing analysis methods for object detection and classification during overburden removal.

  6. Beam extraction experiment with field-emission arrays

    SciTech Connect

    Ishizuka, H.; Watanabe, A.; Shiho, M.

    1995-12-31

    An experimental project aimed to develop FEL drivers using a field-emission array is under way. The subject covers design and fabrication of novel micro-emitters, operation of FEAs, beam formation and emittance diagnostics. So far the generation of a focused beam has been demonstrated with an array of double-gated microemitters. Active control of FEAs has greatly improved the stability of the emission current. Large FEAs with an emitting area of up to 2 x 2 cm{sup 2} have been fabricated for the production of high-current beams. DC beams (1 - 5 keV < 100 {mu}A) extracted from Spindt cathodes were propagated over 1 m and projected on a fluorescent screen. Separate images of FEA tips were observed and emittance measurement has been carried out. The cathode is going to be replaced by a double-gated FEA to improve the beam quality. Pulsed extraction of high currents will also be tested, employing a non-gated FEA as the cathode of a 1 MV induction linac. Results of these experiments will be presented and perspectives concerning the FEA gun will be discussed.

  7. A measurement system applicable for landslide experiments in the field.

    PubMed

    Guo, Wen-Zhao; Xu, Xiang-Zhou; Wang, Wen-Long; Yang, Ji-Shan; Liu, Ya-Kun; Xu, Fei-Long

    2016-04-01

    Observation of gravity erosion in the field with strong sunshine and wind poses a challenge. Here, a novel topography meter together with a movable tent addresses the challenge. With the topography meter, a 3D geometric shape of the target surface can be digitally reconstructed. Before the commencement of a test, the laser generator position and the camera sightline should be adjusted with a sight calibrator. Typically, the topography meter can measure the gravity erosion on the slope with a gradient of 30°-70°. Two methods can be used to obtain a relatively clear video, despite the extreme steepness of the slopes. One method is to rotate the laser source away from the slope to ensure that the camera sightline remains perpendicular to the laser plane. Another way is to move the camera farther away from the slope in which the measured volume of the slope needs to be corrected; this method will reduce distortion of the image. In addition, installation of tent poles with concrete columns helps to surmount the altitude difference on steep slopes. Results observed by the topography meter in real landslide experiments are rational and reliable.

  8. A measurement system applicable for landslide experiments in the field.

    PubMed

    Guo, Wen-Zhao; Xu, Xiang-Zhou; Wang, Wen-Long; Yang, Ji-Shan; Liu, Ya-Kun; Xu, Fei-Long

    2016-04-01

    Observation of gravity erosion in the field with strong sunshine and wind poses a challenge. Here, a novel topography meter together with a movable tent addresses the challenge. With the topography meter, a 3D geometric shape of the target surface can be digitally reconstructed. Before the commencement of a test, the laser generator position and the camera sightline should be adjusted with a sight calibrator. Typically, the topography meter can measure the gravity erosion on the slope with a gradient of 30°-70°. Two methods can be used to obtain a relatively clear video, despite the extreme steepness of the slopes. One method is to rotate the laser source away from the slope to ensure that the camera sightline remains perpendicular to the laser plane. Another way is to move the camera farther away from the slope in which the measured volume of the slope needs to be corrected; this method will reduce distortion of the image. In addition, installation of tent poles with concrete columns helps to surmount the altitude difference on steep slopes. Results observed by the topography meter in real landslide experiments are rational and reliable. PMID:27131688

  9. Field performance of the Walker Branch throughfall displacement experiment

    SciTech Connect

    Hanson, P.J.; Todd, D.E.; Edwards, N.T.; Huston, M.A.

    1994-10-06

    The authors are conducting a large-scale manipulative field experiments in an upland oak forest on the Walker Branch Watershed in eastern Tennessee USA to identify important ecosystem responses that might result from future precipitation changes. The manipulation of soil moisture is being implemented by a gravity-driven transfer of throughfall precipitation from one treatment plot to another. Throughfall is intercepted in {approx} 2,000 subcanopy troughs (0.3 x 5 m) suspended above the forest floor of the dry plots ({approx} 33% of the ground area is covered) and transferred by gravity flow across an ambient plot for subsequent distribution onto the wet treatment plot. Percent soil water is being monitored with time domain reflectometers at 310 sampling locations across the site. The experimental system is able to produce statistically significant differences in soil water content in years having both extremely dry and extremely wet conditions. Furthermore, comparisons of pre- and post-installation soil temperature measurements have documented the ability of the experimental design to produce these changes without changing the microclimate of the forest understory.

  10. Micro-scale hydrological field experiments in Romania

    NASA Astrophysics Data System (ADS)

    Minea, Gabriel; Moroşanu, Gabriela A.

    2016-02-01

    The paper (communication) presents an overview of hydrologic field experiments at micro-scale in Romania. In order to experimentally investigate micro (plot)-scale hydrological impact of soil erosion, the National Institute of Hydrology and Water Management founded Voineşti Experimental Basin (VES) in 1964 and the Aldeni Experimental Basins (AEB) in 1984. AEB and VES are located in the Curvature Subcarpathians. Experimental plots are organized in a double systems and have an area of 80 m2 (runoff plots) at AEB and 300 m2 (water balance plots) at VES. Land use of plot: first plot "grass-land" is covered with perennial grass and second plot (control) consists in "bare soil". Over the latter one, the soil is hoeing, which results in a greater development of infiltration than in the first plot. Experimental investigations at micro-scale are aimed towards determining the parameters of the water balance equation, during natural and artificial rainfalls, researching of flows and soil erosion processes on experimental plots, extrapolating relations involving runoff coefficients from a small scale to medium scale. Nowadays, the latest evolutions in data acquisition and transmission equipment are represented by sensors (such as: sensors to determinate the soil moisture content). Exploitation and dissemination of hydrologic data is accomplished by research themes/projects, year-books of basic data and papers.

  11. Cooperation and conflict: field experiments in Northern Ireland.

    PubMed

    Silva, Antonio S; Mace, Ruth

    2014-10-01

    The idea that cohesive groups, in which individuals help each other, have a competitive advantage over groups composed of selfish individuals has been widely suggested as an explanation for the evolution of cooperation in humans. Recent theoretical models propose the coevolution of parochial altruism and intergroup conflict, when in-group altruism and out-group hostility contribute to the group's success in these conflicts. However, the few empirical attempts to test this hypothesis do not use natural groups and conflate measures of in-group and unbiased cooperative behaviour. We conducted field experiments based on naturalistic measures of cooperation (school/charity donations and lost letters' returns) with two religious groups with an on-going history of conflict-Catholics and Protestants in Northern Ireland. Conflict was associated with reduced donations to out-group schools and the return of out-group letters, but we found no evidence that it influences in-group cooperation. Rather, socio-economic status was the major determinant of cooperative behaviour. Our study presents a challenge to dominant perspectives on the origins of human cooperation, and has implications for initiatives aiming to promote conflict resolution and social cohesion.

  12. Geothermal injection treatment: process chemistry, field experiences, and design options

    SciTech Connect

    Kindle, C.H.; Mercer, B.W.; Elmore, R.P.; Blair, S.C.; Myers, D.A.

    1984-09-01

    The successful development of geothermal reservoirs to generate electric power will require the injection disposal of approximately 700,000 gal/h (2.6 x 10/sup 6/ 1/h) of heat-depleted brine for every 50,000 kW of generating capacity. To maintain injectability, the spent brine must be compatible with the receiving formation. The factors that influence this brine/formation compatibility and tests to quantify them are discussed in this report. Some form of treatment will be necessary prior to injection for most situations; the process chemistry involved to avoid and/or accelerate the formation of precipitate particles is also discussed. The treatment processes, either avoidance or controlled precipitation approaches, are described in terms of their principles and demonstrated applications in the geothermal field and, when such experience is limited, in other industrial use. Monitoring techniques for tracking particulate growth, the effect of process parameters on corrosion and well injectability are presented. Examples of brine injection, preinjection treatment, and recovery from injectivity loss are examined and related to the aspects listed above.

  13. Infrared-temperature variability in a large agricultural field. [Dunnigan, California

    NASA Technical Reports Server (NTRS)

    Millard, J. P.; Goettelman, R. C.; Leroy, M. L. (Principal Investigator)

    1980-01-01

    The combined effect of water carved gullies, varying soil color, moisture state of the soil and crop, nonuniform phenology, and bare spots was measured for commercially grown barley planted on varying terrain. For all but the most rugged terrain, over 80% of the area within 4, 16, 65, and 259 ha cells was at temperatures within 3 C of the mean cell temperature. The result of using relatively small, 4 ha instantaneous field of views for remote sensing applications is that either the worst or the best of conditions is often observed. There appears to be no great advantage in utilizing a small instantaneous field of view instead of a large one for remote sensing of crop canopy temperatures. The two alternatives for design purposes are then either a very high spatial resolution, of the order of a meter or so, where the field is very accurately temperature mapped, or a low resolution, where the actual size seems to make little difference.

  14. Polarization signatures for abandoned agricultural fields in the Manix Basin area of the Mojave Desert

    NASA Technical Reports Server (NTRS)

    Ray, Terrill W.; Farr, Tom G.; Vanzyl, Jakob J.

    1991-01-01

    Polarimetric signatures from abandoned circular alfalfa fields in the Manix Basin area of the Mojave desert show systematic changes with length of abandonment. The obliteration of circular planting rows by surface processes could account for the disappearance of bright 'spokes', which seems to be reflection patterns from remnants of the planting rows, with increasing length of abandonment. An observed shift in the location of the maximum L-band copolarization return away from VV, as well as an increase in surface roughness, both occurring with increasing age of abandonment, seems to be attributable to the formation of wind ripple on the relatively vegetationless fields. A Late Pleistocene/Holocene sand bar deposit, which can be identified in the radar images, is probably responsible for the failure of three fields to match the age sequence patterns in roughness and peak shift.

  15. Operation of agricultural test fields for study of stressed crops by remote sensing

    NASA Technical Reports Server (NTRS)

    Toler, R. W.

    1974-01-01

    A test site for the study of winter wheat development and collection of ERTS data was established in September of 1973. The test site is a 10 mile square area located 12.5 miles west of Amarillo, Texas on Interstate Hwy. 40, in Randall and Potter counties. The center of the area is the Southwestern Great Plains Research Center at Bushland, Texas. Within the test area all wheat fields were identified by ground truth and designated irrigated or dryland. The fields in the test area other than wheat were identified as to pasture or the crop that was grown. A ground truth area of hard red winter wheat was established west of Hale Center, Texas. Maps showing the location of winter wheat fields in excess of 40 acres in size within a 10 mile radius were supplied NASA. Satellite data was collected for this test site (ERTS-1).

  16. Field tracer investigation of unsaturated zone flow paths and mechanisms in agricultural soils of northwestern Mississippi, USA

    NASA Astrophysics Data System (ADS)

    Perkins, Kim S.; Nimmo, John R.; Rose, Claire E.; Coupe, Richard H.

    2011-01-01

    SummaryIn many farmed areas, intensive application of agricultural chemicals and withdrawal of groundwater for irrigation have led to water quality and supply issues. Unsaturated-zone processes, including preferential flow, play a major role in these effects but are not well understood. In the Bogue Phalia basin, an intensely agricultural area in the Delta region of northwestern Mississippi, the fine-textured soils often exhibit surface ponding and runoff after irrigation and rainfall as well as extensive surface cracking during prolonged dry periods. Fields are typically land-formed to promote surface flow into drainage ditches and streams that feed into larger river ecosystems. Downward flow of water below the root zone is considered minimal; regional groundwater models predict only 5% or less of precipitation recharges the heavily used alluvial aquifer. In this study transport mechanisms within and below the root zone of a fallow soybean field were assessed by performing a 2-m ring infiltration test with tracers and subsurface monitoring instruments. Seven months after tracer application, 48 continuous cores were collected for tracer extraction to define the extent of water movement and quantify preferential flow using a mass-balance approach. Vertical water movement was rapid below the pond indicating the importance of vertical preferential flow paths in the shallow unsaturated zone, especially to depths where agricultural disturbance occurs. Lateral flow of water at shallow depths was extensive and spatially non-uniform, reaching up to 10 m from the pond within 2 months. Within 1 month, the wetting front reached a textural boundary at 4-5 m between the fine-textured soil and sandy alluvium, now a potential capillary barrier which, prior to extensive irrigation withdrawals, was below the water table. Within 10 weeks, tracer was detectable at the water table which is presently about 12 m below land surface. Results indicate that 43% of percolation may be through

  17. Field tracer investigation of unsaturated zone flow paths and mechanisms in agricultural soils of northwestern Mississippi, USA

    USGS Publications Warehouse

    Perkins, K.S.; Nimmo, J.R.; Rose, C.E.; Coupe, R.H.

    2011-01-01

    In many farmed areas, intensive application of agricultural chemicals and withdrawal of groundwater for irrigation have led to water quality and supply issues. Unsaturated-zone processes, including preferential flow, play a major role in these effects but are not well understood. In the Bogue Phalia basin, an intensely agricultural area in the Delta region of northwestern Mississippi, the fine-textured soils often exhibit surface ponding and runoff after irrigation and rainfall as well as extensive surface cracking during prolonged dry periods. Fields are typically land-formed to promote surface flow into drainage ditches and streams that feed into larger river ecosystems. Downward flow of water below the root zone is considered minimal; regional groundwater models predict only 5% or less of precipitation recharges the heavily used alluvial aquifer. In this study transport mechanisms within and below the root zone of a fallow soybean field were assessed by performing a 2-m ring infiltration test with tracers and subsurface monitoring instruments. Seven months after tracer application, 48 continuous cores were collected for tracer extraction to define the extent of water movement and quantify preferential flow using a mass-balance approach. Vertical water movement was rapid below the pond indicating the importance of vertical preferential flow paths in the shallow unsaturated zone, especially to depths where agricultural disturbance occurs. Lateral flow of water at shallow depths was extensive and spatially non-uniform, reaching up to 10. m from the pond within 2. months. Within 1. month, the wetting front reached a textural boundary at 4-5. m between the fine-textured soil and sandy alluvium, now a potential capillary barrier which, prior to extensive irrigation withdrawals, was below the water table. Within 10. weeks, tracer was detectable at the water table which is presently about 12. m below land surface. Results indicate that 43% of percolation may be through

  18. What can we learn from field experiments about the development of SOC and GHG emissions under different management practices?

    NASA Astrophysics Data System (ADS)

    Spiegel, Heide; Lehtinen, Taru; Schlatter, Norman; Haslmayr, Hans-Peter; Baumgarten, Andreas; ten Berge, Hein

    2015-04-01

    Successful agricultural management practices are required to maintain or enhance soil quality; at the same time climate change mitigation is becoming increasingly important. Within the EU project CATCH-C we analysed the effects of different agricultural practices not only on crop productivity, but also on soil quality indicators (e.g. soil organic carbon (SOC)) and climate change (CC) mitigation indicators (e.g. CO2, CH4, N2O emissions). European data sets and associated literature, mainly from long-term experiments were evaluated. This evaluation of agricultural management practices was carried out comparing a set of improved ("best") and often applied ("current") management practices. Positive and negative effects occurred when best management practices are adopted. As expected, none of the investigated practices could comply with all objectives simultaneously, i.e. maintaining high yields, mitigating climate change and improving chemical, physical and biological soil quality. The studied soil management practices "non-inversion tillage", "organic fertilisation" (application of farm yard manure, slurry, compost) and "incorporation of crop residues" represent important management practices for farmers to increase SOC, thus improving soil quality. However, CO2 and, especially, N2O emissions may rise as well. The evaluation of CC mitigation is often limited by the lack of data from - preferably - continuous GHG emission measurements. Thus, more long-term field studies are needed to better assess the CO2, CH4 and, especially, N2O emissions following the above mentioned favorably rated MPs. Only if SOC and GHG emissions are measured in the same field experiments, it will be possible to compute overall balances of necessary CO2-C equivalent emissions. CATCH-C is funded within the 7th Framework Programme for Research, Technological Development and Demonstration, Theme 2 - Biotechnologies, Agriculture & Food. (Grant Agreement N° 289782).

  19. Standardization of doctoral study in agricultural and extension education: is the field of study mature enough for achievement of the optimum degree of order?

    PubMed

    Briers, G E; Lindner, J R; Shinn, G C; Wingenbach, G W; Baker, M T

    2010-01-01

    Agricultural and extension education--or some derivative name--is a field of study leading to the doctoral degree in universities around the world. Is there are body of knowledge or a taxonomy of the knowledge--e.g., a knowledge domain--that one should possess with a doctorate in agricultural and extension education? The purpose of this paper was to synthesize the work of researchers who attempted to define the field of study, with a taxonomy comprising the knowledge domains (standards) and knowledge objects--structured interrelated sets of data, knowledge, and wisdom--of the field of study. Doctoral study in agricultural and extension education needs a document that provides for rules and guidelines--rules and guidelines that in turn provide for common and repeated use--all leading to achievement of an optimum degree of order in the context of academic, scholarly, and professional practice in agricultural and extension education. Thus, one would know in broad categories the knowledge, skills, and abilities possessed by one who holds a doctoral degree in agricultural and extension education. That is, there would exist a standard for doctoral degrees in agricultural and extension education. A content analysis of three previous attempts to categorize knowledge in agricultural and extension education served as the primary technique to create a new taxonomy--or to confirm an existing taxonomy--for doctoral study in agricultural and extension education. The following coalesced as nine essential knowledge domains for a doctorate in agricultural and extension education: (1) history, philosophy, ethics, and policy; (2) agricultural/rural development; (3) organizational development and change management; (4) planning, needs assessment, and evaluation; (5) learning theory; (6) curriculum development and instructional design; (7) teaching methods and delivery strategies; (8) research methods and tools; and, (9) scholarship and communications.

  20. Towards the field-scale experiments and numerical modeling of pesticides in tropical soils

    NASA Astrophysics Data System (ADS)

    Dusek, J.; Ray, C.; Sanda, M.; Vogel, T.; Green, R.; Loo, B.

    2004-12-01

    Intensive use of pesticides in agriculture inevitably poses an increased threat to groundwater. Recent findings of pesticide residues in selected drinking water wells in Hawaii brings further attention to this problem since the primary source for potable water in Hawaii is groundwater from basal or dike-confined aquifers. A challenging research project was carried out at the University of Hawaii to elucidate potential impacts of selected pesticides on groundwater and to understand pesticide behavior in tropical soils. The major outcome of the project will be a recommendation to the Hawaii Department of Agriculture whether to restrict or approve these pesticide products entering Hawaii's agricultural market. Three sites on Oahu, one on Maui, and one on Kauai were selected for field evaluation of leaching. The soil types on Oahu are Wahiawa Oxisol (Poamoho), Molokai Oxisol (Kunia), and Waialua Vertisol (Waimanalo). The soil at Kula, Maui is an andisol (loam of Kula series) and that at Mana, Kauai is a Vertisol of Malama series. Three herbicides (S-metolachlor, imazaquin, sulfometuron methyl), one fungicide (trifloxystrobin), and one insecticide (imidacloprid) were used in our study. In addition, a commonly used herbicide (atrazine) and potassium bromide tracer were applied as reference chemicals. After spraying, the plots were covered with straw to decrease evaporation from bare soil surface and irrigated with aerial sprinklers for a period of 16 weeks. Disturbed soil samples from various depths were taken at regular intervals for pesticide analysis. Water flow dynamics was monitored with TDR probes and tensiometers installed at three depths. Weather data were acquired simultaneously. In-situ measurements of unsaturated hydraulic conductivity were done using a tension disc infiltrometer. Laboratory experiments of soil-water retention, as well as degradation, sorption, and column displacement experiments for the selected pesticides were conducted. Hence, comprehensive

  1. Improving water use in agriculture. Experiences in the Middle East and North Africa

    SciTech Connect

    Tuijl, W.V.

    1993-08-01

    As water becomes more scarce, many countries are under pressure to conserve water, especially in the agricultural sector. This paper examines strategies that save water in river basins, irrigation projects, and on farms throughout the Middle East and North Africa. Countries elsewhere can use these suggestions in their own water conservation strategies. Improved surface irrigation techniques and micro-irrigation systems are evaluated. These systems use sprinkler, drip/trickle, or micro-spray methods. The author reviews the preliminary work that is needed to install modern irrigation technologies. He describes the role that governments must play to improve the infrastructure and institutions that affect water use. He also provides detailed case studies of efficient irrigation practices in Cyprus, Israel, and Jordan. These case studies describe the conditions that made better irrigation technology a necessity. They look at ways to plan for development, management, and utilization of water in the face of growing demand. Key topics include how to oversee water rights, adopt essential land reforms, and install a graduated system of water pricing and allocation. The study also recommends projects in water conservation and research.

  2. The Star Thrust Experiment, rotating magnetic field current drive in the field reversed configuration

    NASA Astrophysics Data System (ADS)

    Miller, Kenneth Elric

    2001-11-01

    The Star Thrust Experiment (STX) has formed and sustained the Field Reversed Configuration (FRC) with a Rotating Magnetic Field (RMF) operated at a strength of 25 G and a frequency of 350 kHz. The RMF was generated with two IGBT switched solid state power supplies capable of delivering 2 MW each. Plasmas were typically 2 m long by 0.2m in radius and consisted of fully ionized deuterium at temperatures of 60 eV and peak densities of 5 × 1018m- 3. The primary diagnostic was an extremely small 24 channel berylia jacketed internal magnetic probe that was used to make measurements as a function of time, radius, and axial position. These measurements when combined with the FRC's unique geometry and equilibrium relationships determined many other important plasma parameters. Axial confining fields of 100 G maintained a true vacuum boundary around the plasma and allowed for the study of FRC RMF equilibrium interactions. Key findings are that the RMF maintained a near zero separatrix pressure, penetrated only partially, and drove strong radial and axial flows. Issues discussed include the importance of the RMF driving an axial current distribution consistent with that of the FRC, possible benefits of varying the average beta condition, and potential RMF antenna length limits set by the tendency of driven axial flows to screen the RMF from the plasma.

  3. Rapid field assessment of RO desalination of brackish agricultural drainage water.

    PubMed

    Thompson, John; Rahardianto, Anditya; Gu, Han; Uchymiak, Michal; Bartman, Alex; Hedrick, Marcos; Lara, David; Cooper, Jim; Faria, Jose; Christofides, Panagiotis D; Cohen, Yoram

    2013-05-15

    Rapid field evaluation of RO feed filtration requirements, selection of effective antiscalant type and dose, and estimation of suitable scale-free RO recovery level were demonstrated using a novel approach based on direct observation of mineral scaling and flux decline measurements, utilizing an automated Membrane Monitor (MeMo). The MeMo, operated in a stand-alone single-pass desalting mode, enabled rapid assessment of the adequacy of feed filtration by enabling direct observation of particulate deposition on the membrane surface. The diagnostic field study with RO feed water of high mineral scaling propensity revealed (via direct MeMo observation) that suspended particulates (even for feed water of turbidity <1 NTU) could serve as seeds for promoting surface crystal nucleation. With feed filtration optimized, a suitable maximum RO water recovery, with complete mineral scale suppression facilitated by an effective antiscalant dose, can be systematically and directly identified (via MeMo) in the field for a given feed water quality. Scale-free operating conditions, determined via standalone MeMo rapid diagnostic tests, were shown to be applicable to spiral-would RO system as validated via both flux decline measurements and ex-situ RO plant membrane scale monitoring. It was shown that the present approach is suitable for rapid field assessment of RO operability and it is particularly advantageous when evaluating water sources of composition that may vary both temporally and across the regions of interest. PMID:23538039

  4. Multi-scale satellite assessment of water availability and agricultural drought: from field to global scales

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper discusses a multi-scale remote sensing modeling system that fuses flux assessments generated with TIR imagery collected by multiple satellite platforms to estimate daily surface fluxes from field to global scales. The Landsat series of polar orbiting systems has collected TIR imagery at 6...

  5. Quantifying variability in field scale evapotranspiration measurements in an irrigated agricultural region under advection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study compares the evapotranspiration (ET) measurements from eddy covariance, lysimetry, and water balance using a network of neutron probe sensors and investigates the role of within-field variability in the vegetation density in explaining the differences among the ET estimates from the vario...

  6. Rapid field assessment of RO desalination of brackish agricultural drainage water.

    PubMed

    Thompson, John; Rahardianto, Anditya; Gu, Han; Uchymiak, Michal; Bartman, Alex; Hedrick, Marcos; Lara, David; Cooper, Jim; Faria, Jose; Christofides, Panagiotis D; Cohen, Yoram

    2013-05-15

    Rapid field evaluation of RO feed filtration requirements, selection of effective antiscalant type and dose, and estimation of suitable scale-free RO recovery level were demonstrated using a novel approach based on direct observation of mineral scaling and flux decline measurements, utilizing an automated Membrane Monitor (MeMo). The MeMo, operated in a stand-alone single-pass desalting mode, enabled rapid assessment of the adequacy of feed filtration by enabling direct observation of particulate deposition on the membrane surface. The diagnostic field study with RO feed water of high mineral scaling propensity revealed (via direct MeMo observation) that suspended particulates (even for feed water of turbidity <1 NTU) could serve as seeds for promoting surface crystal nucleation. With feed filtration optimized, a suitable maximum RO water recovery, with complete mineral scale suppression facilitated by an effective antiscalant dose, can be systematically and directly identified (via MeMo) in the field for a given feed water quality. Scale-free operating conditions, determined via standalone MeMo rapid diagnostic tests, were shown to be applicable to spiral-would RO system as validated via both flux decline measurements and ex-situ RO plant membrane scale monitoring. It was shown that the present approach is suitable for rapid field assessment of RO operability and it is particularly advantageous when evaluating water sources of composition that may vary both temporally and across the regions of interest.

  7. Simulation of water balance in a clayey, subsurface drained agricultural field with three-dimensional FLUSH model

    NASA Astrophysics Data System (ADS)

    Warsta, Lassi; Karvonen, Tuomo; Koivusalo, Harri; Paasonen-Kivekäs, Maija; Taskinen, Antti

    2013-01-01

    SummaryWater flow is a key component in the evaluation of soil erosion and nutrient loads from agricultural fields. Field cultivation is the main non-point pollution source threatening water quality of surface waters in Nordic and many other countries. Few models exist that can describe key hydrological processes in clayey soils, i.e. overland flow, preferential flow in macropores and soil shrinkage and swelling. A new three-dimensional (3-D) distributed numerical model called FLUSH is introduced in this study to simulate these processes. FLUSH describes overland flow with the diffuse wave simplification of the Saint Venant equations and subsurface flow with a dual-permeability approach using the Richards equation in both macropore and matrix pore systems. A method based on the pentadiagonal matrix algorithm solves flow in both macropore and matrix systems directly in a column of cells in the computational grid. Flow between the columns is solved with iteration accelerated with OpenMP parallelisation. The model validity is tested with data from a 3-D analytical model and a clayey subsurface drained agricultural field in southern Finland. According to the simulation results, over 99% of the drainflow originated from the macropore system and drainflow started in some cases within the same hour when precipitation started indicating preferential flow in the profile. The moisture content of the clay soil had a profound effect on runoff distribution between surface runoff and drainflow. In summer, when the soil was dry and cracked, drainflow dominated the total runoff, while in autumn, when the shrinkage crack network had swollen shut, surface runoff fraction clearly increased. Observed differences in surface runoff fraction before and after tillage indicated that the operation decreased hydraulic conductivity of the profile.

  8. Seasonal Dynamics in Runoff Generation, Flowpaths and Phosphorus Mobilization From Reduced-till Agricultural Fields in Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Macrae, M. L.; van Esbroeck, C.; Brunke, R.; McKague, K.

    2014-12-01

    Reduced tillage systems used in agriculture have been shown to decrease losses of particulate phosphorus (P), but may increase the risk of dissolved P transport in some landscapes. Most of our knowledge of P losses from agricultural systems is based on observations made during the frost-free season and little is known about winter processes. Given the magnitude of the spring freshet in many regions, it is important to characterize P dynamics during this period. Discharge and P transport in overland flow and subsurface (tile) drainage were monitored at three reduced-till fields in southern Ontario, Canada for 18 months to (1) quantify runoff and P loads from fields; (2) characterize seasonality in the relative contributions of tile drainage and overland flow to runoff and P loads, and (3) demonstrate variable responses among different event types. Transport pathways were active throughout the non-growing season (NGS) and this period accounted for the majority of annual P loads over the study period. Drainage tiles were the dominant hydrologic pathway from fields throughout the study period, but were a small source of P when compared to P loss in overland flow. Overland flow was predominantly observed during winter thaws when ground frost was present. However, the magnitude and speciation of P losses during individual winter events were variable, and, were governed by a combination of antecedent conditions and precipitation characteristics. Given the importance of the NGS to annual P losses, we suggest that management steps should be taken to minimize the risk of losses during this period.

  9. Assessment of soil erosion and deposition rates in a Moroccan agricultural field using fallout 137Cs and 210Pbex.

    PubMed

    Benmansour, M; Mabit, L; Nouira, A; Moussadek, R; Bouksirate, H; Duchemin, M; Benkdad, A

    2013-01-01

    In Morocco land degradation - mainly caused by soil erosion - is one of the most serious agroenvironmental threats encountered. However, only limited data are available on the actual magnitude of soil erosion. The study site investigated was an agricultural field located in Marchouch (6°42' W, 33° 47' N) at 68 km south east from Rabat. This work demonstrates the potential of the combined use of (137)Cs, (210)Pb(ex) as radioisotopic soil tracers to estimate mid and long term erosion and deposition rates under Mediterranean agricultural areas. The net soil erosion rates obtained were comparable, 14.3 t ha(-1) yr(-1) and 12.1 ha(-1) yr(-1) for (137)Cs and (210)Pb(ex) respectively, resulting in a similar sediment delivery ratio of about 92%. Soil redistribution patterns of the study field were established using a simple spatialisation approach. The resulting maps generated by the use of both radionuclides were similar, indicating that the soil erosion processes has not changed significantly over the last 100 years. Over the previous 10 year period, the additional results provided by the test of the prediction model RUSLE 2 provided results of the same order of magnitude. Based on the (137)Cs dataset established, the contribution of the tillage erosion impact has been evaluated with the Mass Balance Model 3 and compared to the result obtained with the Mass Balance Model 2. The findings highlighted that water erosion is the leading process in this Moroccan cultivated field, tillage erosion under the experimental condition being the main translocation process within the site without a significant and major impact on the net erosion.

  10. Aquatic Insect Emergence in Post-Harvest Flooded Agricultural Fields in the Southern San Joaquin Valley, California

    NASA Astrophysics Data System (ADS)

    Moss, R. C.; Blumenshine, S.; Fleskes, J.

    2005-05-01

    California's Southern San Joaquin Valley is one of the most important waterbird areas in North America, but has suffered a disproportionate loss of wetlands when compared to other California regions. This project analyzes the habitat value of post-harvest flooded cropland by measuring the emergence of aquatic insects across multiple crop types. Aquatic insect emergence was sampled from post-harvest flooded fields of four crop types (alfalfa, corn, tomato, wheat), August-October, 2003-2004. Emergence was measured using traps deployed with a stratified random distribution to sample between and within field variation. Emergence rate and emergent biomass was significantly higher in flooded tomato fields. Results from corn fields indicate that flooding depth was correlated (r=0.095) with both diel temperature fluctuation and emergence rate. Chironomus dilutus larvae were grown in environmental chambers, under two thermal treatments with the same mean but different amplitudes (high: 15°-32°C, low: 20°-26°C) to investigate thermal fluctuation effects on survival and biomass. Larval survival (4x) and biomass (2x) were significantly greater in the low versus high temperature fluctuation treatment. This research has the potential to affect agricultural management throughout the 12,600 km2 region, increase aquatic insect production and aid in the recovery of declining bird populations.

  11. A Teaching Experiment in the Use of Greenhouse Facilities in Vocational Agriculture.

    ERIC Educational Resources Information Center

    Drawbaugh, Charles Calvin

    Major purposes were to measure the comparative effectiveness of school greenhouses, community greenhouses, and classroom windowsills and a laboratory manual, functional experience, and teacher's own method for learning plant science principles relative to the environmental factors of light, temperature, moisture, aeration, and nutrients. Minor…

  12. Modelling field scale water partitioning using on-site observations in sub-Saharan rainfed agriculture

    NASA Astrophysics Data System (ADS)

    Makurira, H.; Savenije, H. H. G.; Uhlenbrook, S.

    2009-08-01

    Smallholder rainfed farming systems generally realise sub-optimal crop yields which are largely attributed to dry spell occurrences during crop growth stages. However, with improved farming practices, it seems possible to significantly increase yield levels even with little and highly variable rainfall. The presented results follow research conducted in the Makanya catchment in northern Tanzania where gross rainfall amounts to less than 400 mm/season which is insufficient to support staple food crops (e.g. maize). Alternative cultivation techniques such as runoff harvesting and in-field micro-storage structures are compared. These techniques aim to reduce soil and nutrient loss from the field but, more importantly, promote in-field infiltration and water retention. Water balance components have been observed in order to study water partitioning processes under different cultivation techniques. Based on rainfall, soil evaporation, transpiration, runoff and soil moisture measurements, a water balance model has been developed to simulate soil moisture variations over the growing season. It appears that about 50% of the diverted water leaves the root zone through deep percolation. Modelling shows that during the field trials the average productive transpiration flow ranged between 1.1-1.4 mm d-1 in the trial plots compared to 0.7-1.0 mm d-1 under traditional tillage practice. Productive transpiration processes accounted for 23-29% while losses to deep percolation accounted for 33-48% of the available water. Conclusions from the research are that the innovations tested are effective in enhancing soil moisture retention at field scale and that diversions allow crop growth moisture conditions to be attained with early rains. It is also concluded that there is more scope for efficient utilisation of the diverted runoff water if storage structures could be installed to regulate water flow to the root zone when required.

  13. 3-D modeling of water balance and soil erosion in a clayey subsurface drained agricultural field in boreal climate

    NASA Astrophysics Data System (ADS)

    Turunen, M.; Warsta, L.; Koivusalo, H. J.; Paasonen-Kivekäs, M.; Nurminen, J.; Myllys, M.; Alakukku, L.; Äijö, H.; Puustinen, M.

    2012-12-01

    Fluxes of nutrients and other substances from cultivated fields cause eutrophication and deterioration of water quality in aquatic ecosystems worldwide. In order to develop effective strategies to control the environmental impacts of crop cultivation, it is crucial to identify the main transport pathways and the effects of different water management methods on the loads. Reduction of sediment loads is essential since sediment particles typically carry nutrients (especially sorbed phosphorus) and other potentially harmful substances, e.g. pesticides, from the fields to the adjacent surface waters. The novel part of this study was the investigation of suspended sediment transport in soil macropores to the subsurface drains and to the deep groundwater. We applied a 3-D distributed dual-permeability model (FLUSH) using a dataset collected from a subsurface drained, clayey agricultural field (15 ha) to holistically assess water balance, soil erosion and sediment transport from the field to an adjacent stream. The data set included five years of hydrological and water quality measurements from four intensively monitored field sections with different soil properties, topography, drainage systems (drain spacing and drain depth), drain installation methods (trenchless and trench drainage) and drain envelope materials (gravel and fiber). The 3-D model allowed us to quantify how soil erosion and sediment transport differed between the field sections within the field area. The simulations were conducted during snow- and frost-free periods. The simulation results include closure of water balance of the cultivated field, distribution of soil erosion and sediment transport within the field area and the effects of different subsurface drainage systems on sediment loads. The 3-D dual-permeability subsurface flow model was able to reproduce the measured drainflows and sediment fluxes in the clayey field and according to the simulations over 90% of drainflow waters were conveyed to

  14. Rainwater lens dynamics and mixing between infiltrating rainwater and upward saline groundwater seepage beneath a tile-drained agricultural field

    NASA Astrophysics Data System (ADS)

    de Louw, P. G. B.; Eeman, S.; Oude Essink, G. H. P.; Vermue, E.; Post, V. E. A.

    2013-09-01

    Thin rainwater lenses (RW-lenses) near the land surface are often the only source of freshwater in agricultural areas with regionally-extensive brackish to saline groundwater. The seasonal and inter-annual dynamics of these lenses are poorly known. Here this knowledge gap is addressed by investigating the transient flow and mixing processes in RW-lenses beneath two tile-drained agricultural fields in the Netherlands. Evidence of RW-lens dynamics was systematically collected by monthly ground- and soil water sampling, in combination with daily observations of water table elevation, drain tile discharge and drain water salinity. Based on these data, and numerical modeling of the key lens characteristics, a conceptual model of seasonal lens dynamics is presented. It is found that variations in the position of the mixing zone and mixing zone salinities are small and vary on a seasonal timescale, which is attributed to the slow transient oscillatory flow regime in the deepest part of the lens. The flow and mixing processes are faster near the water table, which responds to recharge and evapotranspiration at a timescale less than a day. Variations of drain tile discharge and drain water salinity are also very dynamic as they respond to individual rain events. Salinities of soil water can become significantly higher than in the groundwater. This is attributed to the combined effect of capillary rise of saline groundwater during dry periods and incomplete flushing by infiltrating freshwater due to preferential flow through cracks in the soil. The results of this study are the key to understanding the potential impact of future climate change and to designing effective mitigating measures such as adapting tile-drainage systems to ensure the future availability of freshwater for agriculture.

  15. Chemical and biological characterization of products of incomplete combustion from the simulated field burning of agricultural plastic.

    PubMed

    Linak, W P; Ryan, J V; Perry, E; Williams, R W; DeMarini, D M

    1989-06-01

    Chemical and biological analyses were performed to characterize products of incomplete combustion emitted during the simulated open field burning of agricultural plastic. A small utility shed equipped with an air delivery system was used to simulate pile burning and forced-air-curtain incineration of a nonhalogenated agricultural plastic that reportedly consisted of polyethylene and carbon black. Emissions were analyzed for combustion gases; volatile, semi-volatile, and particulate organics; and toxic and mutagenic properties. Emission samples, as well as samples of the used (possibly pesticide-contaminated) plastic, were analyzed for the presence of several pesticides to which the plastic may have been exposed. Although a variety of alkanes, alkenes, and aromatic and polycyclic aromatic hydrocarbon (PAH) compounds were identified in the volatile, semi-volatile, and particulate fractions of these emissions, a substantial fraction of higher molecular weight organic material was not identified. No pesticides were identified in either combustion emission samples or dichloromethane washes of the used plastic. When mutagenicity was evaluated by exposing Salmonella bacteria (Ames assay) to whole vapor and vapor/particulate emissions, no toxic or mutagenic effects were observed. However, organic extracts of the particulate samples were moderately mutagenic. This mutagenicity compares approximately to that measured from residential wood heating on a revertant per unit heat release basis. Compared to pile burning, forced air slightly decreased the time necessary to burn a charge of plastic. There was not a substantial difference, however, in the variety or concentrations of organic compounds identified in samples from these two burn conditions. This study highlights the benefits of a combined chemical/biological approach to the characterization of complex, multi-component combustion emissions. These results may not reflect those of other types of plastic that may be used

  16. Planning an integrated agriculture and health program and designing its evaluation: Experience from Western Kenya

    PubMed Central

    Cole, Donald C.; Levin, Carol; Loechl, Cornelia; Thiele, Graham; Grant, Frederick; Girard, Aimee Webb; Sindi, Kirimi; Low, Jan

    2016-01-01

    Multi-sectoral programs that involve stakeholders in agriculture, nutrition and health care are essential for responding to nutrition problems such as vitamin A deficiency among pregnant and lactating women and their infants in many poor areas of lower income countries. Yet planning such multi-sectoral programs and designing appropriate evaluations, to respond to different disciplinary cultures of evidence, remain a challenge. We describe the context, program development process, and evaluation design of the Mama SASHA project (Sweetpotato Action for Security and Health in Africa) which promoted production and consumption of a bio-fortified, orange-fleshed sweetpotato (OFSP). In planning the program we drew upon information from needs assessments, stakeholder consultations, and a first round of the implementation evaluation of a pilot project. The multi-disciplinary team worked with partner organizations to develop a program theory of change and an impact pathway which identified aspects of the program that would be monitored and established evaluation methods. Responding to the growing demand for greater rigour in impact evaluations, we carried out quasi-experimental allocation by health facility catchment area, repeat village surveys for assessment of change in intervention and control areas, and longitudinal tracking of individual mother-child pairs. Mid-course corrections in program implementation were informed by program monitoring, regular feedback from implementers and partners’ meetings. To assess economic efficiency and provide evidence for scaling we collected data on resources used and project expenses. Managing the multi-sectoral program and the mixed methods evaluation involved bargaining and trade-offs that were deemed essential to respond to the array of stakeholders, program funders and disciplines involved. PMID:27003730

  17. Seasonal fluctuations of bacterial community diversity in agricultural soil and experimental validation by laboratory disturbance experiments.

    PubMed

    Meier, Christoph; Wehrli, Bernhard; van der Meer, Jan Roelof

    2008-08-01

    Natural fluctuations in soil microbial communities are poorly documented because of the inherent difficulty to perform a simultaneous analysis of the relative abundances of multiple populations over a long time period. Yet, it is important to understand the magnitudes of community composition variability as a function of natural influences (e.g., temperature, plant growth, or rainfall) because this forms the reference or baseline against which external disturbances (e.g., anthropogenic emissions) can be judged. Second, definition of baseline fluctuations in complex microbial communities may help to understand at which point the systems become unbalanced and cannot return to their original composition. In this paper, we examined the seasonal fluctuations in the bacterial community of an agricultural soil used for regular plant crop production by using terminal restriction fragment length polymorphism profiling (T-RFLP) of the amplified 16S ribosomal ribonucleic acid (rRNA) gene diversity. Cluster and statistical analysis of T-RFLP data showed that soil bacterial communities fluctuated very little during the seasons (similarity indices between 0.835 and 0.997) with insignificant variations in 16S rRNA gene richness and diversity indices. Despite overall insignificant fluctuations, between 8 and 30% of all terminal restriction fragments changed their relative intensity in a significant manner among consecutive time samples. To determine the magnitude of community variations induced by external factors, soil samples were subjected to either inoculation with a pure bacterial culture, addition of the herbicide mecoprop, or addition of nutrients. All treatments resulted in statistically measurable changes of T-RFLP profiles of the communities. Addition of nutrients or bacteria plus mecoprop resulted in bacteria composition, which did not return to the original profile within 14 days. We propose that at less than 70% similarity in T-RFLP, the bacterial communities risk to

  18. Planning an integrated agriculture and health program and designing its evaluation: Experience from Western Kenya.

    PubMed

    Cole, Donald C; Levin, Carol; Loechl, Cornelia; Thiele, Graham; Grant, Frederick; Girard, Aimee Webb; Sindi, Kirimi; Low, Jan

    2016-06-01

    Multi-sectoral programs that involve stakeholders in agriculture, nutrition and health care are essential for responding to nutrition problems such as vitamin A deficiency among pregnant and lactating women and their infants in many poor areas of lower income countries. Yet planning such multi-sectoral programs and designing appropriate evaluations, to respond to different disciplinary cultures of evidence, remain a challenge. We describe the context, program development process, and evaluation design of the Mama SASHA project (Sweetpotato Action for Security and Health in Africa) which promoted production and consumption of a bio-fortified, orange-fleshed sweetpotato (OFSP). In planning the program we drew upon information from needs assessments, stakeholder consultations, and a first round of the implementation evaluation of a pilot project. The multi-disciplinary team worked with partner organizations to develop a program theory of change and an impact pathway which identified aspects of the program that would be monitored and established evaluation methods. Responding to the growing demand for greater rigour in impact evaluations, we carried out quasi-experimental allocation by health facility catchment area, repeat village surveys for assessment of change in intervention and control areas, and longitudinal tracking of individual mother-child pairs. Mid-course corrections in program implementation were informed by program monitoring, regular feedback from implementers and partners' meetings. To assess economic efficiency and provide evidence for scaling we collected data on resources used and project expenses. Managing the multi-sectoral program and the mixed methods evaluation involved bargaining and trade-offs that were deemed essential to respond to the array of stakeholders, program funders and disciplines involved. PMID:27003730

  19. Planning an integrated agriculture and health program and designing its evaluation: Experience from Western Kenya.

    PubMed

    Cole, Donald C; Levin, Carol; Loechl, Cornelia; Thiele, Graham; Grant, Frederick; Girard, Aimee Webb; Sindi, Kirimi; Low, Jan

    2016-06-01

    Multi-sectoral programs that involve stakeholders in agriculture, nutrition and health care are essential for responding to nutrition problems such as vitamin A deficiency among pregnant and lactating women and their infants in many poor areas of lower income countries. Yet planning such multi-sectoral programs and designing appropriate evaluations, to respond to different disciplinary cultures of evidence, remain a challenge. We describe the context, program development process, and evaluation design of the Mama SASHA project (Sweetpotato Action for Security and Health in Africa) which promoted production and consumption of a bio-fortified, orange-fleshed sweetpotato (OFSP). In planning the program we drew upon information from needs assessments, stakeholder consultations, and a first round of the implementation evaluation of a pilot project. The multi-disciplinary team worked with partner organizations to develop a program theory of change and an impact pathway which identified aspects of the program that would be monitored and established evaluation methods. Responding to the growing demand for greater rigour in impact evaluations, we carried out quasi-experimental allocation by health facility catchment area, repeat village surveys for assessment of change in intervention and control areas, and longitudinal tracking of individual mother-child pairs. Mid-course corrections in program implementation were informed by program monitoring, regular feedback from implementers and partners' meetings. To assess economic efficiency and provide evidence for scaling we collected data on resources used and project expenses. Managing the multi-sectoral program and the mixed methods evaluation involved bargaining and trade-offs that were deemed essential to respond to the array of stakeholders, program funders and disciplines involved.

  20. Modelling field scale water partitioning using on-site observations in sub-Saharan rainfed agriculture

    NASA Astrophysics Data System (ADS)

    Makurira, H.; Savenije, H. H. G.; Uhlenbrook, S.

    2010-04-01

    Smallholder rainfed farming systems generally realise sub-optimal crop yields which are largely attributed to dry spell occurrences during crop growth stages. However, through the introduction of appropriate farming practices, it is possible to substantially increase yield levels even with little and highly variable rainfall. The presented results follow research conducted in the Makanya catchment in northern Tanzania where gross rainfall amounts to less than 400 mm/season which is insufficient to support staple food crops (e.g. maize). The yields from farming system innovations (SIs), which are basically alternative cultivation techniques, are compared against traditional farming practices. The SIs tested in this research are runoff harvesting used in combination with in-field trenches and soil bunds (fanya juus). These SIs aim to reduce soil and nutrient loss from the field and, more importantly, promote in-field infiltration and water retention. Water balance components have been observed in order to study water partitioning processes for the "with" and "without" SI scenarios. Based on rainfall, soil evaporation, transpiration, runoff and soil moisture measurements, a water balance model has been developed to simulate soil moisture variations over the growing season. Simulation results show that, during the field trials, the average productive transpiration flow ranged between 1.1-1.4 mm d-1 in the trial plots compared to 0.7-1.0 mm d-1 under traditional tillage practice. Productive transpiration processes accounted for 23-29% while losses to deep percolation accounted for 33-48% of the available water. The field system has been successfully modelled using the spreadsheet-based water balance 1-D model. Conclusions from the research are that the SIs that were tested are effective in enhancing soil moisture retention at field scale and that diversions allow crop growth moisture conditions to be attained with early rains. From the partitioning analysis, it is also

  1. Prehistoric Agriculture and Soil Fertility on Lava Flows in Northern Arizona, USA: Results from the San Francisco Volcanic Field REU

    NASA Astrophysics Data System (ADS)

    Broadman, E.; Anderson, K. C.

    2013-12-01

    The San Francisco Volcanic Field in northern Arizona is home to ~600 cinder cones, the youngest of which is Sunset Crater (erupted ~AD 1100). This study documents trends in available phosphate and nitrate content with time, testing whether lowered soil pH from the addition of Sunset cinders increased soil fertility and became a factor in Anasazi agricultural success. Soil fertility is examined both before and after Sunset's eruption in soils of different ages that have developed from eolian deposition on top of lava flows. An increase in phosphate and nitrate levels following acidification would suggest that the presence of Sunset cinders brought the soils to the optimal pH for mobilization of these nutrients. The combined effects of the cinder layer retaining nutrients and water, wetter climates, and increases in phosphate and nitrate (both limiting nutrients for plant growth), would have contributed to Anasazi agricultural success after Sunset's eruption. Samples for this study were taken from eolian-derived soils of different ages atop lava flows in the San Francisco Volcanic Field. OSL data from these soils on Strawberry and SP Craters' lava flows yielded age estimates of ~12.3 ka (Strawberry) and ~32.7 ka (SP), on which a soil chronosequence was based. Results from the chronosequence supported these OSL ages, indicating that soils on the SP flow are older than those on the Strawberry flow. Field descriptions, Harden Development Indices, particle size analysis, and nutrient content analysis were used for this aspect of the project. An experimental acid wash method will be used to simulate the addition of Sunset's acidic cinders, and will yield data for phosphate and nitrate content after Sunset erupted. Preliminary results indicate that phosphate and nitrate accumulate in upper, eolian-derived horizons (Av, Bw) and in more deeply buried carbonate horizons (Bk). Higher concentrations of phosphate and nitrate were found in older (SP) soils than younger

  2. Agricultural terraces montoring and modeling: a field survey in Chianti region, Firenze, Italy – Second part

    NASA Astrophysics Data System (ADS)

    Preti, Federico; Caruso, Marco; Dani, Andrea; Cassiani, Giorgio; Romano, Nunzio; Tarolli, Paolo

    2015-04-01

    sustainable management of erosion processes in agricultural land and hilly-mountainous area

  3. High Magnetic field generation for laser-plasma experiments

    SciTech Connect

    Pollock, B B; Froula, D H; Davis, P F; Ross, J S; Fulkerson, S; Bower, J; Satariano, J; Price, D; Glenzer, S H

    2006-05-01

    An electromagnetic solenoid was developed to study the effect of magnetic fields on electron thermal transport in laser plasmas. The solenoid, which is driven by a pulsed power system suppling 30 kJ, achieves magnetic fields of 13 T. The field strength was measured on the solenoid axis with a magnetic probe and optical Zeeman splitting. The measurements agree well with analytical estimates. A method for optimizing the solenoid design to achieve magnetic fields exceeding 20 T is presented.

  4. Exposure to sulfosulfuron in agricultural drainage ditches: field monitoring and scenario-based modelling.

    PubMed

    Brown, Colin D; Dubus, Igor G; Fogg, Paul; Spirlet, Marie; Gustin, Christophe

    2004-08-01

    Field monitoring and scenario-based modelling were used to assess exposure of small ditches in the UK to the herbicide sulfosulfuron following transport via field drains. A site in central England on a high pH, clay soil was treated with sulfosulfuron, and concentrations were monitored in the single drain outfall and in the receiving ditch 1 km downstream. Drainflow in the nine months following application totalled 283 mm. Pesticide lost in the first 12.5 mm of flow was 99% of the total loading to drains (0.5% of applied). Significant dilution was observed in the receiving ditch and quantifiable residues were only detected in one sample (0.06 microg litre(-1)). The MACRO model was evaluated against the field data with minimal calibration. The parameterisation over-estimated the importance of macropore flow at the site. As a consequence, the maximum concentration in drainflow (2.3 microg litre(-1)) and the total loading to drains (0.76 g) were over-estimated by factors of 2.4 and 5, respectively. MACRO was then used to simulate long-term fate of the herbicide for each of 20 environmental scenarios. Resulting estimates for concentrations of sulfosulfuron in a receiving ditch were weighted according to the prevalence of each scenario to produce a probability distribution of daily exposure. PMID:15307668

  5. Experiments of Flow Field Influenced by Vegetation Distribution on Floodplain

    NASA Astrophysics Data System (ADS)

    Li, Jin-Fu; Wang, Shun-Chang; Chen, Su-Chin

    2015-04-01

    The vegetation on floodplain can block river flow, raise flood level, and scour riverbed downstream the vegetation region. However, it can also protect the dike, reduce flood velocity, and increase the stability of channel. This experiment analyzed the relationship between vegetation distribution and flow field. We designed three vegetation arrangement pattern of unilateral vegetation, unilateral interval vegetation and no vegetation, respectively. The unilateral vegetation was defined as a 4.9 m length and 0.5 m width with vegetative area in one side of the experiment flume. The unilateral interval vegetation was defined as the same dimension of vegetative area but inserted 2 gaps with 1 m interval, and the vegetative area was separated into 3 blocks. The model of a single plant was assembled with stem and frond. The stem was a woody cylinder with 10 cm height and 2.2 cm in diameter. The other part was plastic frond with 10 cm in height. The flume was 20 m length, 1 m width and 0.7 m height with 2 kinds of bed slopes in 0.001 and 0.002, and 3 different discharges in 0.2 m3/s, 0.145 m3/s and 0.0855 m3/s. The velocity was measured by 2-D electromagnetic velocimeter (ACM2-R2). In addition, water depth was measured by Vernier calipers. The velocity distribution showed that the current were divided into two parts. In the part of inside vegetation area, water level uplifted when flow entering the vegetation area, and it declined until the current leaving vegetation area. Compared with the current in the other half part of flume, the magnitudes of uplift were about 50% in both case of unilateral vegetation and unilateral interval vegetation. Downstream the vegetation area edge, the water level dropped immediately and violently. The water depth was shallower than that in the other half non-vegetation part, and the decline magnitude were 48% and 39% in cases of unilateral vegetation and unilateral interval vegetation, respectively. To explain this phenomenon, we measured

  6. Remote sensing for precision agriculture: Within-field spatial variability analysis and mapping with aerial digital multispectral images

    NASA Astrophysics Data System (ADS)

    Gopalapillai, Sreekala

    2000-10-01

    Advances in remote sensing technology and biological sensors provided the motivation for this study on the applications of aerial multispectral remote sensing in precision agriculture. The feasibility of using high-resolution multispectral remote sensing for precision farming applications such as soil type delineation, identification of crop nitrogen levels, and modeling and mapping of weed density distribution and yield potential within a crop field was explored in this study. Some of the issues such as image calibration for variable lighting conditions and soil background influence were also addressed. Intensity normalization and band ratio methods were found to be adequate image calibration methods to compensate for variable illumination and soil background influence. Several within-field variability factors such as growth stage, field conditions, nutrient availability, crop cultivar, and plant population were found to be dominant in different periods. Unsupervised clustering of color infrared (CIR) image of a field soil was able to identify soil mapping units with an average accuracy of 76%. Spectral reflectance from a crop field was highly correlated to the chlorophyll reading. A regression model developed to predict nitrogen stress in corn identified nitrogen-stressed areas from nitrogen-sufficient areas with a high accuracy (R2 = 0.93). Weed density was highly correlated to the spectral reflectance from a field. One month after planting was found to be a good time to map spatial weed density. The optimum range of resolution for weed mapping was 4 m to 4.5 m for the remote sensing system and the experimental field used in this study. Analysis of spatial yield with respect to spectral reflectance showed that the visible and NIR reflectance were negatively correlated to yield and crop population in heavily weed-infested areas. The yield potential was highly correlated to image indices, especially to normalized brightness. The ANN model developed for one of the

  7. Net global warming potential and greenhouse gas intensity in rice agriculture driven by high yields and nitrogen use efficiency: a 5 year field study

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Zhou, Z.; Liu, Y.; Xu, X.; Wang, J.; Zhang, H.; Xiong, Z.

    2015-11-01

    Our understanding of how net global warming potential (NGWP) and greenhouse gas intensity (GHGI) is affected by management practices aimed at food security with respect to rice agriculture remains limited. In the present study, a 5 year field experiment was conducted in China to evaluate the effects of integrated soil-crop system management (ISSM) on NGWP and GHGI after accounting for carbon dioxide (CO2) emissions from all sources (methane, CH4, and nitrous oxide, N2O, emissions, agrochemical inputs, Ei, and farm operations, Eo) and sinks (i.e., soil organic carbon, SOC, sequestration). For the improvement of rice yield and agronomic nitrogen use efficiency (NUE), four ISSM scenarios consisting of different nitrogen (N) fertilization rates relative to the local farmers' practice (FP) rate were carried out, namely, N1 (25 % reduction), N2 (10 % reduction), N3 (FP rate) and N4 (25 % increase). The results showed that compared with the FP, the four ISSM scenarios, i.e., N1, N2, N3 and N4, significantly increased the rice yields by 10, 16, 28 and 41 % and the agronomic NUE by 75, 67, 86 and 82 %, respectively. In addition, compared with the FP, the N1 and N2 scenarios significantly reduced the GHGI by 14 and 18 %, respectively, despite similar NGWPs. The N3 and N4 scenarios remarkably increased the NGWP and GHGI by an average of 67 and 36 %, respectively. In conclusion, the ISSM strategies are promising for both food security and environmental protection, and the ISSM scenario of N2 is the optimal strategy to realize high yields and high NUE together with low environmental impacts for this agricultural rice field.

  8. Controls on Nitrogen Fluxes from Agricultural Fields: Differing Conclusions Based on Choice of Sensitivity Analysis Method

    NASA Astrophysics Data System (ADS)

    Ahrens, T.; Matson, P.; Lobell, D.

    2006-12-01

    Sensitivity analyses (SA) of biogeochemical and agricultural models are often used to identify the importance of input variables for variance in model outputs, such as crop yield or nitrate leaching. Identification of these factors can aid in prioritizing efforts in research or decision support. Many types of sensitivity analyses are available, ranging from simple One-At-A-Time (OAT) screening exercises to more complex local and global variance-based methods (see Saltelli et al 2004). The purpose of this study was to determine the influence of the type of SA on factor prioritization in the Yaqui Valley, Mexico using the Water and Nitrogen Management Model (WNMM; Chen et al 2005). WNMM, a coupled plant-growth - biogeochemistry simulation model, was calibrated to reproduce crop growth, soil moisture, and gaseous N emission dynamics in experimental plots of irrigated wheat in the Yaqui Valley, Mexico from 1994-1997. Three types of SA were carried out using 16 input variables, including parameters related to weather, soil properties and crop management. Methods used for SA were local OAT, Monte Carlo (MC), and a global variance-based method (orthogonal input; OI). Results of the SA were based on typical interpretations used for each test: maximum absolute ratio of variation (MAROV) for OAT analyses; first- and second-order regressions for MC analyses; and a total effects index for OI. The three most important factors identified by MC and OI methods were generally in agreement, although the order of importance was not always consistent and there was little agreement for variables of less importance. OAT over-estimated the importance of two factors (planting date and pH) for many outputs. The biggest differences between the OAT results and those from MC and OI were likely due to the inability of OAT methods to account for non-linearity (eg. pH and ammonia volatilization), interactions among variables (eg. pH and timing of fertilization) and an over-reliance on baseline

  9. Nitrate transport and fluxes during storm-event discharge from a 12 ha tile-drained dryland agricultural field

    NASA Astrophysics Data System (ADS)

    Kelley, C. J.; Keller, C. K.; Brooks, E. S.; Smith, J. L.; Orr, C. H.; Evans, R. D.

    2012-12-01

    Tile drains shortcut natural soil hydrology and decrease the capacity of soils to buffer water and nutrient fluxes during storm events. Previous research at the Cook Agronomy Farm near Pullman, WA. found seasonal patterns for nutrient and water fluxes, larger during the winter and smaller during the summer. The objective of this study was to determine the effects storm events have on tile-drain water and nutrient fluxes from a dryland agricultural field. Our first hypothesis is that winter storm events activate shallow soil-water flow paths, resulting in rapid transport of precipitation and younger soil pore-water through the tile-drain system. These storm-event flow paths result in a decrease in tile-drain water electrical conductivity from a baseline of approximately 260 μS/cm to as low as 20 μS/ cm. Data suggest that storm events increase hydraulic conductivities in the upper profile as soil approaches saturation, increasing the contributions of relatively young soil water and possibly current storm-event precipitation to tile-drain discharge. Our second hypothesis is that the observed increase in discharge during storm events does not decrease nitrate concentrations in discharged water, because the storm-event flow paths also transport additional nitrate from the upper soil profile through the tile-drain system. If this hypothesis is correct, during storm events nitrate fluxes should increase, indicating rapid mobilization and potential flushing of soil nutrients through the vadose zone and tile-drain. If nitrate fluxes remain constant during storm events, then decreased tile-drain nitrate concentrations may be caused by the addition of low-nitrate or nitrate-free water. This would suggest that the nitrate leached from the system is present at the depth of the tile-drain and is not transported from near the soil surface to the tile-drain during storm-events, indicating flushing of soil nutrients from the rooting zone is not occurring at these temporal scales

  10. Experimental monitoring and numerical study of pesticide (carbofuran) transfer in an agricultural soil at a field site

    NASA Astrophysics Data System (ADS)

    Hmimou, Abderrahim; Maslouhi, Abdellatif; Tamoh, Karim; Candela, Lucila

    2014-09-01

    We studied the transport of a pesticide at field scale, namely carbofuran molecule, which is known for its high mobility, especially in sandy soils with high hydraulic conductivity and low organic matter. To add to our knowledge of the future of this high-mobility molecule in this type of soils, we developed a mechanistic numerical model allowing the simulation of hydric and solute transfers (bromide and carbofuran) in the soil. We carried out this study in an agricultural plot in the region of Mnasra in Morocco. Confrontation of the measured and simulated values allowed the calibration of the parameters of hydric transfer and carbofuran. The developed model accurately reproduces the measured values. Despite a weak irrigation and precipitation regime, carbofuran was practically leached beyond the root zone. Prospective simulations show that under a more important irrigation regime, carbofuran reaches a 100-cm depth, whereas it does not exceed 60 cm under a deficit regime.

  11. Temporal variability of colloidal material in agricultural storm runoff from managed grassland using flow field-flow fractionation.

    PubMed

    Gimbert, Laura J; Worsfold, Paul J

    2009-12-25

    This paper reports the use of flow field-flow fractionation (FlFFF) to determine the temporal variability of colloidal (<1mum) particle size distributions in agricultural runoff waters in a small managed catchment in SW England during storm events. Three storm events of varying intensity were captured and the colloidal material in the runoff analysed by FlFFF. The technique had sufficient sensitivity to determine directly the changing colloidal profile over the 0.08-1.0mum size range in the runoff waters during these storm events. Rainfall, total phosphorus and suspended solids in the bulk runoff samples were also determined throughout one storm and showed significant correlation (P<0.01) with the amount of colloidal material. Whilst there are some uncertainties in the resolution and absolute calibration of the FlFFF profiles, the technique has considerable potential for the quantification of colloidal material in storm runoff waters. PMID:19577239

  12. Vineyard weeds control practices impact on surface water transfers: using numerical tracer experiment coupled to a distributed hydrological model to manage agricultural practices spatial arrangements.

    NASA Astrophysics Data System (ADS)

    Colin, F.; Moussa, R.

    2009-04-01

    In rural basins, agricultural landscape management highly influences water and pollutants transfers. Landuse, agricultural practices and their spatial arrangements are at issue. Hydrological model are widely used to explore impacts of anthropogenic influences on experimental catchments. But planning all spatial arrangements leads to a possible cases count which cannot be considered. On the basis of the recent « numerical experiment » approach, we propose a « numerical tracer function » which had to be coupled to a distributed rainfall-runoff model. This function simulate the transfer of a virtual tracer successively spread on each distributed unit inside the catchment. It allows to rank hydrological spatial units according to their hydrological contribution to the surface flows, particularly at the catchment outlet. It was used with the distributed model MHYDAS in an agricultural context. The case study concerns the experimental Roujan vine-growing catchment (1km², south of France) studied since 1992. In this Mediterranean context, we focus on the soil hydraulic conductivity distributed parameter because it highly depends on weed control practices (chemical weeding induces a lot more runoff than mechanical weeding). We checked model sensitivity analysis to soil hydraulic conductivity spatial arrangement on runoff coefficient, peak discharge and catchment lag-time. Results show (i) the use of the tracer function is more efficient than a random approach to improve sensitivity to spatial arrangements from point of view of simulated discharge range, (ii) the first factor explaining hydrological simulations variability was practices area ratio, (iii) variability induced by practices spatial arrangements was significant on runoff coefficient and peak discharge for balanced practices area ratio and on lag-time for low area ratio of chemical weeding practices. From the actual situation on the experimental Roujan catchment (40% of tilled and 60% of non tilled vineyard

  13. Thresholds of copper phytotoxicity in field-collected agricultural soils exposed to copper mining activities in Chile.

    PubMed

    Verdejo, José; Ginocchio, Rosanna; Sauvé, Sébastien; Salgado, Eduardo; Neaman, Alexander

    2015-12-01

    It has been argued that the identification of the phytotoxic metal thresholds in soil should be based on field-collected soil rather than on artificially-contaminated soils. However, the use of field-collected soils presents several difficulties for interpretation because of mixed contamination and unavoidable covariance of metal contamination with other soil properties that affect plant growth. The objective of this study was to estimate thresholds of copper phytotoxicity in topsoils of 27 agricultural areas historically contaminated by mining activities in Chile. We performed emergence and early growth (21 days) tests (OECD 208 and ISO 11269-2) with perennial ryegrass (Lolium perenne L.). The total Cu content in soils was the best predictor of plant growth and shoot Cu concentrations, while soluble Cu and pCu(2+) did not well correlate with these biological responses. The effects of Pb, Zn, and As on plant responses were not significant, suggesting that Cu is a metal of prime concern for plant growth in soils exposed to copper mining activities in Chile. The effects of soil nutrient availability and shoot nutrient concentrations on ryegrass response were not significant. It was possible to determine EC10, EC25 and EC50 of total Cu in the soil of 327 mg kg(-1), 735 mg kg(-1) and 1144 mg kg(-1), respectively, using the shoot length as a response variable. However, the derived 95% confidence intervals for EC10, EC25 and EC50 values of total soil Cu were wide, and thus not allowing a robust assessment of metal toxicity for agricultural crops, based on total soil Cu concentrations. Thus, plant tests might need to be performed for metal toxicity assessment. This study suggests shoot length of ryegrass as a robust response variable for metal toxicity assessment in contaminated soils with different nutrient availability.

  14. Thresholds of copper phytotoxicity in field-collected agricultural soils exposed to copper mining activities in Chile.

    PubMed

    Verdejo, José; Ginocchio, Rosanna; Sauvé, Sébastien; Salgado, Eduardo; Neaman, Alexander

    2015-12-01

    It has been argued that the identification of the phytotoxic metal thresholds in soil should be based on field-collected soil rather than on artificially-contaminated soils. However, the use of field-collected soils presents several difficulties for interpretation because of mixed contamination and unavoidable covariance of metal contamination with other soil properties that affect plant growth. The objective of this study was to estimate thresholds of copper phytotoxicity in topsoils of 27 agricultural areas historically contaminated by mining activities in Chile. We performed emergence and early growth (21 days) tests (OECD 208 and ISO 11269-2) with perennial ryegrass (Lolium perenne L.). The total Cu content in soils was the best predictor of plant growth and shoot Cu concentrations, while soluble Cu and pCu(2+) did not well correlate with these biological responses. The effects of Pb, Zn, and As on plant responses were not significant, suggesting that Cu is a metal of prime concern for plant growth in soils exposed to copper mining activities in Chile. The effects of soil nutrient availability and shoot nutrient concentrations on ryegrass response were not significant. It was possible to determine EC10, EC25 and EC50 of total Cu in the soil of 327 mg kg(-1), 735 mg kg(-1) and 1144 mg kg(-1), respectively, using the shoot length as a response variable. However, the derived 95% confidence intervals for EC10, EC25 and EC50 values of total soil Cu were wide, and thus not allowing a robust assessment of metal toxicity for agricultural crops, based on total soil Cu concentrations. Thus, plant tests might need to be performed for metal toxicity assessment. This study suggests shoot length of ryegrass as a robust response variable for metal toxicity assessment in contaminated soils with different nutrient availability. PMID:26233921

  15. Estimation of spatio-temporal variability of soil water content in agricultural fields with ground penetrating radar

    NASA Astrophysics Data System (ADS)

    Wijewardana, Y. G. N. S.; Galagedara, L. W.

    2010-09-01

    SummaryEfficient water management, crop yield variability estimation and prediction of contaminant transport require some measurement of soil water content variation through time and space. This study focused on the estimation of spatio-temporal variability of volumetric soil water content ( θ v) in raised bed agricultural fields using ground penetrating radar (GPR), comparison of GPR method with gravimetric sampling data and development of 2D maps of θ v. The GPR system (pulse EKKO Pro) with 200 MHz antennas was used to collect data on approximately 1.0 m wide and 13.0 m long raised beds of about 0.1 m height cultivated with vegetables. Transillumination Zero Offset Profile (Trans ZOP) and Transillumination Multiple Offset Gather (Trans MOG) GPR survey modes which are classically used as borehole GPR method were employed as a surface GPR method. In each of these survey modes, the direct ground wave travel time was measured. The θ v at each Trans ZOP and Trans MOG location was calculated by first converting the electromagnetic (EM) wave velocity into soil dielectric permittivity and then to θ v using a standard empirical relationship. The results revealed that the spatio-temporal variability of θ v in raised bed agricultural fields could be estimated using the Trans ZOP and Trans MOG GPR survey modes. The GPR estimated θ v and gravimetrically measured soil water content ( θ g) were not significantly different ( P = 0.272). The correlation coefficient was 0.87, the root mean square error was 0.0184 m 3/m 3 and the average error was 0.20% between the two methods. The Trans MOG survey data allowed us to create plan view maps (2D) of the θ v variation which could not be obtained from the Trans ZOP data. No statistical difference ( P = 0.053) was found between the Trans ZOP and average Trans MOG values.

  16. Building Development, Food and Population Issues in the Field of Agriculture with Rural Development in the Arab Countries (16-21 January 1993). Panel discussion (seminar).

    PubMed

    Morcos, M E

    1993-01-01

    The UN Organization for Food and Agriculture bureau held a panel discussion during January 16-21, 1993, to stress the importance of the joint relation between population issues, food, and nutrition in the fields of agriculture and rural development. Policymakers and individuals responsible for activities and programs on population, food, nutrition, and rural development in Egypt, Tunisia, Morocco, Jordan, Yemen, and Sudan participated in the seminar. The seminar was also attended by academic institutions and participants from the ministries of agriculture and health, the National Population Council, and the committees of the countries involved. Synopses of panel proceedings are presented.

  17. Controlling factors of nitrous oxide (N2O) emissions at the field-scale in an agricultural slope

    NASA Astrophysics Data System (ADS)

    Vilain, Guillaume; Garnier, Josette; Tallec, Gaëlle; Tournebize, Julien; Cellier, Pierre; Flipo, Nicolas

    2010-05-01

    Agricultural practices widely contribute to the atmospheric nitrous oxide (N2O) concentration increase and are the major source of N2O which account for 24% of the global annual emission (IPCC, 2007). Soil nitrification and denitrification are the microbial processes responsible for the production of N2O, which also depends on soil characteristics and management. Besides their control by various factors, such as climate, soil conditions and management (content of NO3- and NH4+, soil water content, presence of degradable organic material…), the role of topography is less known although it can play an important role on N2O emissions (Izaurralde et al., 2004). Due to the scarcity of data on N2O direct vs. indirect emission rate from agriculture in the Seine Basin (Garnier et al., 2009), one of the objectives of the study conducted here was to determine the N2O emission rates of the various land use representative for the Seine Basin, in order to better assess the direct N2O emissions, and to explore controlling factor such as meteorology, topography, soil properties and crop successions. The main objective of this study was at the same time to characterize N2O fluxes variability along a transect from an agricultural plateau to a river and to analyze the influence of landscape position on these emissions. We conducted this study in the Orgeval catchment (Seine basin, France; between 48°47' and 48°55' N, and 03°00' and 03°55' E) from May 2008 to August 2009 on two agricultural fields cropped with wheat, barley, oats, corn. N2O fluxes were monitored from weekly to bimonthly using static manual chambers placed along the chosen transect in five different landscape positions from the plateau to the River. This study has shown that soil moisture (expressed as Water Filled Pore Space) and NO3- soil concentrations explained most of the N2O flux variability during the sampling period. Most of N2O was emitted directly after N fertilization application during a relatively

  18. Measurements of the effectiveness of conservation agriculture at the field scale using radioisotopic techniques and runoff plots

    NASA Astrophysics Data System (ADS)

    Mabit, L.; Klik, A.; Toloza, A.; Benmansour, M.; Geisler, A.; Gerstmann, U. C.

    2009-04-01

    Growing evidence of the cost of soil erosion on agricultural land and off site impact of associated processes has emphasized the needs for quantitative assessment of erosion rates to develop and assess erosion control technology and to allocate conservation resources and development of conservation regulation, policies and programmes. Our main study goal was to assess the magnitude of deposition rates using Fallout Radionuclides ‘FRNs' (137-Cs and 210-Pb) and the mid-term (13 years) erosion rates using conventional runoff plot measurements in a small agricultural watershed under conventional and conservation tillage practices. The tillage treatments were conventional tillage system (CT), mechanical plough to 30 cm depth (the most common tillage system within the watershed); conservation tillage (CS) with cover crops during winter; and direct seeding (DS) no tillage with cover crops during winter. The experimental design - located in Mistelbach watershed 60 km north of Vienna/Austria - consists of one 3-metre-wide and 15-metre-long runoff plot (silt loam - slope of 14%) for each tillage system (CT, CS and DS) with the plots placed in the upper part of an agricultural field. 76 soil samples were collected to evaluate the initial fallout of 137-Cs and 210-Pb in a small forested area close to the experimental field, along a systematic multi-grid design,. In the sedimentation area of the watershed and down slope the agricultural field, 2 additional soil profiles were collected to 1 m depth. All soil samples were air dried, sieved to 2mm and analysed for their 137-Cs and 210-Pb contents using gamma detector. The main results and conclusion can be summarised as following: i) The initial 137-Cs fallout as measured in the 76 forested soil samples ranged from 1123 to 3354 Bq/m2 for an average of 1954 Bq/m2 with a coefficient of variation of 20.4 %. ii) Long-term erosion measurements (1994-2006) from runoff plots located in the upper part of the agricultural field just up

  19. Runoff of pharmaceuticals and personal care products following application of biosolids to an agricultural field.

    PubMed

    Topp, Edward; Monteiro, Sara C; Beck, Andrew; Coelho, Bonnie Ball; Boxall, Alistair B A; Duenk, Peter W; Kleywegt, Sonya; Lapen, David R; Payne, Michael; Sabourin, Lyne; Li, Hongxia; Metcalfe, Chris D

    2008-06-15

    Municipal biosolids are a source of nutrients for crop production. Beneficial Management Practices (BMPs) can be used to minimize the risk of contamination of adjacent water resources with chemical or microbial agents that are of public or environmental health concern. In this field study, we applied biosolids slurry at a commercial rate using either subsurface injection or broadcast application followed by incorporation. Precipitation was simulated at 1, 3, 7, 22, 36 and 266 days post-application on 2 m(2) microplots to evaluate surface runoff of 9 model pharmaceuticals and personal care products (PPCPs), atenolol, carbamazepine, cotinine, gemfibrozil, naproxen, ibuprofen, acetaminophen, sulfamethoxazole and triclosan. In runoff from the injected plots, concentrations of the model PPCPs were generally below the limits of quantitation. In contrast, in the broadcast application treatment, the concentrations of atenolol, carbamazepine, cotinine, gemfibrozil, naproxen, sulfamethoxazole and triclosan on the day following application ranged from 70-1477 ng L(-1) in runoff and generally declined thereafter with first order kinetics. The total mass of PPCPs mobilized in surface runoff per m(2) of the field ranged from 0.63 microg for atenolol to 21.1 microg for ibuprofen. For ibuprofen and acetaminophen, concentrations in runoff first decreased and then increased, suggesting that these drugs were initially chemically or physically sequestered in the biosolids slurry, and subsequently released in the soil. Carbamazepine and triclosan were detected at low concentrations in a runoff event 266 days after broadcast application. Overall, this study showed that injection of biosolids slurry below the soil surface could effectively eliminate surface runoff of PPCPs. PMID:18377955

  20. Multi-frequency SAR data for soil surface moisture estimation over agricultural fields

    NASA Astrophysics Data System (ADS)

    Zribi, Mehrez; Baghdadi, Nicolas

    2015-04-01

    Soil moisture plays a crucial role in the continental water cycle, in particular through its influence on the distribution of precipitation between surface runoff and infiltration, which is the main driver behind most hydrological and geomorphologic processes. Although there is now a good understanding of soil hydrodynamics and water transfer in porous media, the development of reliable techniques allowing field heterogeneities to be fully analyzed in space and time remains a key issue. In recent decades, various inversion models have been proposed for the retrieval of surface parameters (mainly soil moisture and surface roughness) from Synthetic Aperture Radar (SAR) high resolution measurements. The proposed techniques depend particularly on two instrumental parameters: the radar system's spatial resolution and the number of configurations measured during satellite acquisitions (mainly incidence angle and polarization). In this paper, our objective is to illustrate different applications of SAR data to estimate soil moisture over bare soil and vegetation cover areas (wheat, olive groves, meadows ...). Potential of very high resolution data, with the availability of TerraSAR-X and COSMO-SkyMed constellations is also discussed. This study is based on different experimental campaigns organized over different sites in humid and semi-arid regions. Ground measurements (soil moisture, soil roughness, vegetation description) over test fields were carried out simultaneously to SAR measurements. Effect of vegetation attenuation on radar signal is considered through a synergy with optical remote sensing. Soil moisture precision for all proposed applications is generally ranged between 3 and 5% of volumetric moisture. These methodologies are developed in the context of the preparation for having a high soil moisture operational product, with SENTINEL and/or the other planned constellations. After an analysis of radar data sensitivity (C and X bands) to surface parameters

  1. Field Experiments Aimed To The Analysis of Flood Generation Processes

    NASA Astrophysics Data System (ADS)

    Carriero, D.; Iacobellis, V.; Oliveto, G.; Romano, N.; Telesca, V.; Fiorentino, M.

    The study of the soil moisture dynamics and of the climate-soil-vegetation interac- tion is essential for the comprehension of possible climatic change phenomena, as well as for the analysis of occurrence of extreme hydrological events. In this trend the theoretically-based distribution of floods recently derived by Fiorentino and Ia- cobellis, [ŞNew insights about the climatic and geologic control on the probability distribution of floodsT, Water Resources Research, 2001, 37: 721-730] demonstrated, by an application in some Southern Italy basins, that processes at the hillslope scale strongly influence the basin response by means of the different mechanisms of runoff generation produced by various distributions of partial area contributing. This area is considered as a stochastic variable whose pdf position parameter showed strong de- pendence on the climate as it can seen in the studied basins behavior: in dry zones, where there is the prevalence of the infiltration excess (Horton) mechanism, the basin water loss parameter decreases as basin area increases and the flood peak source area depends on the permeability of soils; in humid zones, with the prevalence of satu- ration excess (Dunne) process, the loss parameter seems independent from the basin area and very sensitive to simple climatic index while only small portion of the area invested by the storm contributes to floods. The purpose of this work is to investigate the consistency of those interpretations by means of field experiments at the hillslope scale to establish a parameterization accounting for soil physical and hydraulic prop- erties, vegetation characteristics and land-use. The research site is the catchment of River Fiumarella di Corleto, which is located in Basilicata Region, Italy, and has a drainage area of approximately 32 km2. The environment has a rather dynamic geo- morphology and very interesting features from the soil-landscape modeling viewpoint [Santini A., A. Coppola, N. Romano, and

  2. Nitrogen Cycle Modeling: a Mechanistic Estimate of N-losses From Agricultural Fields Over the Seasonal Time Period

    NASA Astrophysics Data System (ADS)

    Maggi, F.; Gu, C.; Venterea, R.; Riley, W.; Oldenburg, C.

    2007-12-01

    The biogeochemical cycle of nitrogen and production of NO, N2O, and CO2 gas and NO2- and NO3- ions in nutrient-enriched agricultural fields is mediated by soil microbial activity, the hydrological cycle, plant dynamics, and climatic forcing. Understanding how NO, N2O, CO2 gases and NO2- and NO3- ions are released from agricultural fields to the environment is a key factor in controlling the green-house effect and water contamination, and assumes ever greater importance in view of the foreseen increase in biofuel, food, and fiber production. To address these issues we have developed a mechanistic model (TOUGHREACT-N) for various nitrification and denitrification pathways, multiple microbial biomass dynamics, heat and water flows, and various chemical reactions at local and kinetic equilibrium. The soil column is represented in a 1D framework, with hydraulic properties described by a water tension-saturation model. Biotic and abiotic reactions are assumed to follow Michaelis-Menten kinetics, while a consortium of several micro-organismal strains is assumed to follow multiple Monod growth kinetics accounting for electron donor, electron acceptor, and inhibitor concentrations. Water flow is modeled with the Darcy-Richards equation, while nutrient transport is modeled by Fickian advective and diffusive processes in both gaseous and liquid phases. Heat flow is modeled with the Fourier equation. Plant dynamics is taken into account by coupling TOUGHREACT-N with CERES to determine water and nutrient uptake, and soil carbon accumulation. TOUGHREACT-N was calibrated against field measurements to assess pathways of N losses following fertilization. A good agreement between field observations and model predictions was found. We identified two dominant time scales in the system response that depended on plants dynamics. Before plants have substantial impact on soil nutrients and moisture content, N losses are characterized by rapid increases as a function of water application

  3. Exploring the Role of Field Experience Context in Preservice Teachers' Development as Mathematics Educators

    ERIC Educational Resources Information Center

    Cooper, Sandi; Nesmith, Suzanne

    2013-01-01

    Although the importance of field experience is supported and attended to by teacher education programs across the United States, there have been numerous national reports and research findings stressing the need for major improvements in the preparation of teachers with an emphasis on more authentic experiences. Quality field experiences have the…

  4. The Examination of a Mentoring Relationship during a Metadiscrete Physical Education Field Experience

    ERIC Educational Resources Information Center

    Bower, Glenna G.; Bonnett, Stephanie

    2009-01-01

    Universities strive to graduate well-rounded individuals with opportunities to gain knowledge in the classroom and experience in the "real world". Therefore, many colleges focus their attention to offering discrete field experiences. However, few universities offer metadiscrete field experiences, with students majoring in exercise science or…

  5. A Field Trip to Gettysburg: A Model Experience.

    ERIC Educational Resources Information Center

    Olcott, Mark S.

    1987-01-01

    Using Gettysburg as an example, the author addresses the major components of a successful field trip, such as pre-teaching, memorizing, and the study of primary sources. Includes information on student participation and other factors of a successful field trip. (GEA)

  6. Measuring the Interest of German Students in Agriculture: The Role of Knowledge, Nature Experience, Disgust, and Gender

    ERIC Educational Resources Information Center

    Bickel, Malte; Strack, Micha; Bögeholz, Susanne

    2015-01-01

    Modern knowledge-based societies, especially their younger members, have largely lost their bonds to farming. However, learning about agriculture and its interrelations with environmental issues may be facilitated by students' individual interests in agriculture. To date, an adequate instrument to investigate agricultural interests has been…

  7. Conditions for Successful Field Experiences: Perceptions of Cooperating Teachers

    ERIC Educational Resources Information Center

    Graham, Barbara

    2006-01-01

    In this study I have profiled the background experiences, academic preparation and perceptions of a small number of cooperating teachers in a secondary Professional Development School site about their experiences in successful practice. The results indicate that cooperating teachers have a depth of understanding of their role in the process and…

  8. Instantaneous and daily values of the surface energy balance over agricultural fields using remote sensing and a reference field in an arid environment

    USGS Publications Warehouse

    Kustas, W.P.; Moran, M.S.; Jackson, R. D.; Gay, L.W.; Duell, L.F.W.; Kunkel, K.E.; Matthias, A.D.

    1990-01-01

    Remotely sensed surface temperature and reflectance in the visible and near infrared wavebands along with ancilliary meteorological data provide the capability of computing three of the four surface energy balance components (i.e., net radiation, soil heat flux, and sensible heat flux) at different spatial and temporal scales. As a result, under nonadvective conditions, this enables the estimation of the remaining term (i.e., the latent heat flux). One of the practical applications with this approach is to produce evapotranspiration (ET) maps for agricultural regions which consist of an array of fields containing different crops at varying stages of growth and soil moisture conditions. Such a situation exists in the semiarid southwest at the University of Arizona Maricopa Agricultural Center, south of Phoenix. For one day (14 June 1987), surface temperature and reflectance measurements from an aircraft 150 m above ground level (agl) were acquired over fields from zero to nearly full cover at four times between 1000 MST and 1130 MST. The diurnal pattern of the surface energy balance was measured over four fields, which included alfalfa at 60% cover, furrowed cotton at 20% and 30% cover, and partially plowed what stubble. Instantaneous and daily values of ET were estimated for a representative area around each flux site with an energy balance model that relies on a reference ET. This reference value was determined with remotely sensed data and several meteorological inputs. The reference ET was adjusted to account for the different surface conditions in the other fields using only remotely sensed variables. A comparison with the flux measurements suggests the model has difficulties with partial canopy conditions, especially related to the estimation of the sensible heat flux. The resulting errors for instantaneous ET were on the order of 100 W m-2 and for daily values of order 2 mm day-1. These findings suggest future research should involve development of methods to

  9. Keeping agricultural soil out of rivers: evidence of sediment and nutrient accumulation within field wetlands in the UK.

    PubMed

    Ockenden, Mary C; Deasy, Clare; Quinton, John N; Surridge, Ben; Stoate, Chris

    2014-03-15

    Intensification of agriculture has resulted in increased soil degradation and erosion, with associated pollution of surface waters. Small field wetlands, constructed along runoff pathways, offer one option for slowing down and storing runoff in order to allow more time for sedimentation and for nutrients to be taken up by plants or micro-organisms. This paper describes research to provide quantitative evidence for the effectiveness of small field wetlands in the UK landscape. Ten wetlands were built on four farms in Cumbria and Leicestershire, UK. Annual surveys of sediment and nutrient accumulation in 2010, 2011 and 2012 indicated that most sediment was trapped at a sandy site (70 tonnes over 3 years), compared to a silty site (40 tonnes over 3 years) and a clay site (2 tonnes over 3 years). The timing of rainfall was more important than total annual rainfall for sediment accumulation, with most sediment transported in a few intense rainfall events, especially when these coincided with bare soil or poor crop cover. Nutrient concentration within sediments was inversely related to median particle size, but the total mass of nutrients trapped was dependent on the total mass of sediment trapped. Ratios of nutrient elements in the wetland sediments were consistent between sites, despite different catchment characteristics across the individual wetlands. The nutrient value of sediment collected from the wetlands was similar to that of soil in the surrounding fields; dredged sediment was considered to have value as soil replacement but not as fertiliser. Overall, small field wetlands can make a valuable contribution to keeping soil out of rivers.

  10. Keeping agricultural soil out of rivers: evidence of sediment and nutrient accumulation within field wetlands in the UK.

    PubMed

    Ockenden, Mary C; Deasy, Clare; Quinton, John N; Surridge, Ben; Stoate, Chris

    2014-03-15

    Intensification of agriculture has resulted in increased soil degradation and erosion, with associated pollution of surface waters. Small field wetlands, constructed along runoff pathways, offer one option for slowing down and storing runoff in order to allow more time for sedimentation and for nutrients to be taken up by plants or micro-organisms. This paper describes research to provide quantitative evidence for the effectiveness of small field wetlands in the UK landscape. Ten wetlands were built on four farms in Cumbria and Leicestershire, UK. Annual surveys of sediment and nutrient accumulation in 2010, 2011 and 2012 indicated that most sediment was trapped at a sandy site (70 tonnes over 3 years), compared to a silty site (40 tonnes over 3 years) and a clay site (2 tonnes over 3 years). The timing of rainfall was more important than total annual rainfall for sediment accumulation, with most sediment transported in a few intense rainfall events, especially when these coincided with bare soil or poor crop cover. Nutrient concentration within sediments was inversely related to median particle size, but the total mass of nutrients trapped was dependent on the total mass of sediment trapped. Ratios of nutrient elements in the wetland sediments were consistent between sites, despite different catchment characteristics across the individual wetlands. The nutrient value of sediment collected from the wetlands was similar to that of soil in the surrounding fields; dredged sediment was considered to have value as soil replacement but not as fertiliser. Overall, small field wetlands can make a valuable contribution to keeping soil out of rivers. PMID:24509365

  11. Evaluation of the leucine incorporation technique for detection of pollution-induced community tolerance to copper in a long-term agricultural field trial with urban waste fertilizers.

    PubMed

    Lekfeldt, Jonas Duus Stevens; Magid, Jakob; Holm, Peter E; Nybroe, Ole; Brandt, Kristian Koefoed

    2014-11-01

    Copper (Cu) is known to accumulate in agricultural soils receiving urban waste products as fertilizers. We here report the use of the leucine incorporation technique to determine pollution-induced community tolerance (Leu-PICT) to Cu in a long-term agricultural field trial. A significantly increased bacterial community tolerance to Cu was observed for soils amended with organic waste fertilizers and was positively correlated with total soil Cu. However, metal speciation and whole-cell bacterial biosensor analysis demonstrated that the observed PICT responses could be explained entirely by Cu speciation and bioavailability artifacts during Leu-PICT detection. Hence, the agricultural application of urban wastes (sewage sludge or composted municipal waste) simulating more than 100 years of use did not result in sufficient accumulation of Cu to select for Cu resistance. Our findings also have implications for previously published PICT field studies and demonstrate that stringent PICT detection criteria are needed for field identification of specific toxicants.

  12. Trapping runoff, sediment and nutrients at the edge-of-field: Using constructed wetlands to control runoff and improve water quality in agricultural catchments

    NASA Astrophysics Data System (ADS)

    Deasy, Clare; Quinton, John; Stoate, Chris

    2010-05-01

    Across Europe, many rivers and lakes are polluted. In the UK, the Biodiversity Action Plan estimates that over 70% of lakes are eutrophic. Diffuse pollution from agriculture is currently of extreme concern, but pollution and flood risk can be mitigated by management activities. The use of in-field mitigation options such as reduced tillage has been found to be effective at reducing runoff, sediment and nutrient loss in overland flow, but pollutants can still be lost from hillslopes unchecked via subsurface flow pathways, some of which may contribute very high loads of nutrients to streams. Edge-of-field mitigation approaches, which can tackle both surface and subsurface pathways at locations where they discharge into ditches and streams, therefore have greater potential as runoff control measures than in-field measures alone. In the UK, the implementation, effectiveness and functioning of seven new wetlands constructed at the edges of agricultural fields is currently being assessed. The constructed wetlands, of different designs, which are fed by different flow types and are located on different farm and soil types, are continuously monitored for discharge and turbidity at inlets and outlets, while storm sampling allows assessment of sediment and nutrient transfer into and out of the wetland at times when there is a high risk of pollutant transfer. Pond surveys and sediment sampling will take place annually, and tracer experiments will be carried out in the course of the project. The data will be used to generate information on sediment and nutrient load reductions or wetland effectiveness, wetland sediment and nutrient budgets, and water and sediment residence times. In this paper we present the initial results, including novel high-resolution data from the first monitored events. Early outputs suggest that constructed wetlands which receive surface runoff inputs can retain flood waters and may reduce flood peaks, wetlands built to take drain outfalls may be

  13. Field-Based Stable Isotope Probing Reveals the Identities of Benzoic Acid-Metabolizing Microorganisms and Their In Situ Growth in Agricultural Soil▿

    PubMed Central

    Pumphrey, Graham M.; Madsen, Eugene L.

    2008-01-01

    We used a combination of stable isotope probing (SIP), gas chromatography-mass spectrometry-based respiration, isolation/cultivation, and quantitative PCR procedures to discover the identity and in situ growth of soil microorganisms that metabolize benzoic acid. We added [13C]benzoic acid or [12C]benzoic acid (100 μg) once, four times, or five times at 2-day intervals to agricultural field plots. After monitoring 13CO2 evolution from the benzoic acid-dosed soil, field soils were harvested and used for nucleic acid extraction and for cultivation of benzoate-degrading bacteria. Exposure of soil to benzoate increased the number of culturable benzoate degraders compared to unamended soil, and exposure to benzoate shifted the dominant culturable benzoate degraders from Pseudomonas species to Burkholderia species. Isopycnic separation of heavy [13C]DNA from the unlabeled fraction allowed terminal restriction fragment length polymorphism (T-RFLP) analyses to confirm that distinct 16S rRNA genes were localized in the heavy fraction. Phylogenetic analysis of sequenced 16S rRNA genes revealed a predominance (15 of 58 clones) of Burkholderia species in the heavy fraction. Burkholderia sp. strain EBA09 shared 99.5% 16S rRNA sequence similarity with a group of clones representing the dominant RFLP pattern, and the T-RFLP fragment for strain EBA09 and a clone from that cluster matched the fragment enriched in the [13C]DNA fraction. Growth of the population represented by EBA09 during the field-dosing experiment was demonstrated by using most-probable-number-PCR and primers targeting EBA09 and the closely related species Burkholderia hospita. Thus, the target population identified by SIP not only actively metabolized benzoic acid but reproduced in the field upon the addition of the substrate. PMID:18469130

  14. Field-based stable isotope probing reveals the identities of benzoic acid-metabolizing microorganisms and their in situ growth in agricultural soil.

    PubMed

    Pumphrey, Graham M; Madsen, Eugene L

    2008-07-01

    We used a combination of stable isotope probing (SIP), gas chromatography-mass spectrometry-based respiration, isolation/cultivation, and quantitative PCR procedures to discover the identity and in situ growth of soil microorganisms that metabolize benzoic acid. We added [(13)C]benzoic acid or [(12)C]benzoic acid (100 microg) once, four times, or five times at 2-day intervals to agricultural field plots. After monitoring (13)CO(2) evolution from the benzoic acid-dosed soil, field soils were harvested and used for nucleic acid extraction and for cultivation of benzoate-degrading bacteria. Exposure of soil to benzoate increased the number of culturable benzoate degraders compared to unamended soil, and exposure to benzoate shifted the dominant culturable benzoate degraders from Pseudomonas species to Burkholderia species. Isopycnic separation of heavy [(13)C]DNA from the unlabeled fraction allowed terminal restriction fragment length polymorphism (T-RFLP) analyses to confirm that distinct 16S rRNA genes were localized in the heavy fraction. Phylogenetic analysis of sequenced 16S rRNA genes revealed a predominance (15 of 58 clones) of Burkholderia species in the heavy fraction. Burkholderia sp. strain EBA09 shared 99.5% 16S rRNA sequence similarity with a group of clones representing the dominant RFLP pattern, and the T-RFLP fragment for strain EBA09 and a clone from that cluster matched the fragment enriched in the [(13)C]DNA fraction. Growth of the population represented by EBA09 during the field-dosing experiment was demonstrated by using most-probable-number-PCR and primers targeting EBA09 and the closely related species Burkholderia hospita. Thus, the target population identified by SIP not only actively metabolized benzoic acid but reproduced in the field upon the addition of the substrate.

  15. CWEX (Crop/Wind-Energy Experiment): Measurements of the interaction between crop agriculture and wind power

    NASA Astrophysics Data System (ADS)

    Rajewski, Daniel Andrew

    The current expansion of wind farms in the U.S. Midwest promotes an alternative renewable energy portfolio to conventional energy sources derived from fossil fuels. The construction of wind turbines and large wind farms within several millions of cropland acres creates a unique interaction between two unlike energy sources: electric generation by wind and bio-fuel production derived from crop grain and plant tissues. Wind turbines produce power by extracting mean wind speed and converting a portion of the flow to turbulence downstream of each rotor. Turbine-scale turbulence modifies fluxes of momentum, heat, moisture, and other gaseous constituents (e.g. carbon dioxide) between the crop canopy and the atmospheric boundary layer. Conversely, crop surfaces and tillage elements produce drag on the hub-height wind resource, and the release of sensible and latent heat flux from the canopy or soil influences the wind speed profile. The Crop-Wind Energy Experiment (CWEX) measured momentum, energy, and CO2 fluxes at several locations within the leading line of turbines in a large operational wind farm, and overall turbines promote canopy mixing of wind speed, temperature, moisture, and carbon dioxide in both the day and night. Turbine-generated perturbations of these fluxes are dependent on several factors influencing the turbine operation (e.g. wind speed, wind direction, stability, orientation of surrounding turbines within a wind park) and the cropland surface (e.g. crop type and cultivar, planting density, chemical application, and soil composition and drainage qualities). Additional strategies are proposed for optimizing the synergy between crop and wind power.

  16. Leaching of glyphosate and amino-methylphosphonic acid from Danish agricultural field sites.

    PubMed

    Kjaer, Jeanne; Olsen, Preben; Ullum, Marlene; Grant, Ruth

    2005-01-01

    Pesticide leaching is an important process with respect to contamination risk to the aquatic environment. The risk of leaching was thus evaluated for glyphosate (N-phosphonomethyl-glycine) and its degradation product AMPA (amino-methylphosphonic acid) under field conditions at one sandy and two loamy sites. Over a 2-yr period, tile-drainage water, ground water, and soil water were sampled and analyzed for pesticides. At a sandy site, the strong soil sorption capacity and lack of macropores seemed to prevent leaching of both glyphosate and AMPA. At one loamy site, which received low precipitation with little intensity, the residence time within the root zone seemed sufficient to prevent leaching of glyphosate, probably due to degradation and sorption. Minor leaching of AMPA was observed at this site, although the concentration was generally low, being on the order of 0.05 microg L(-1) or less. At another loamy site, however, glyphosate and AMPA leached from the root zone into the tile drains (1 m below ground surface [BGS]) in average concentrations exceeding 0.1 microg L(-1), which is the EU threshold value for drinking water. The leaching of glyphosate was mainly governed by pronounced macropore flow occurring within the first months after application. AMPA was frequently detected more than 1.5 yr after application, thus indicating a minor release and limited degradation capacity within the soil. Leaching has so far been confined to the depth of the tile drains, and the pesticides have rarely been detected in monitoring screens located at lower depths. This study suggests that as both glyphosate and AMPA can leach through structured soils, they thereby pose a potential risk to the aquatic environment.

  17. Field-based evidence for consistent responses of bacterial communities to copper contamination in two contrasting agricultural soils

    PubMed Central

    Li, Jing; Ma, Yi-Bing; Hu, Hang-Wei; Wang, Jun-Tao; Liu, Yu-Rong; He, Ji-Zheng

    2015-01-01

    Copper contamination on China's arable land could pose severe economic, ecological and healthy consequences in the coming decades. As the drivers in maintaining ecosystem functioning, the responses of soil microorganisms to long-term copper contamination in different soil ecosystems are still debated. This study investigated the impacts of copper gradients on soil bacterial communities in two agricultural fields with contrasting soil properties. Our results revealed consistent reduction in soil microbial biomass carbon (SMBC) with increasing copper levels in both soils, coupled by significant declines in bacterial abundance in most cases. Despite of contrasting bacterial community structures between the two soils, the bacterial diversity in the copper-contaminated soils showed considerably decreasing patterns when copper levels elevated. High-throughput sequencing revealed copper selection for major bacterial guilds, in particular, Actinobacteria showed tolerance, while Acidobacteria and Chloroflexi were highly sensitive to copper. The thresholds that bacterial communities changed sharply were 800 and 200 added copper mg kg−1 in the fluvo-aquic soil and red soil, respectively, which were similar to the toxicity thresholds (EC50 values) characterized by SMBC. Structural equation model (SEM) analysis ascertained that the shifts of bacterial community composition and diversity were closely related with the changes of SMBC in both soils. Our results provide field-based evidence that copper contamination exhibits consistently negative impacts on soil bacterial communities, and the shifts of bacterial communities could have largely determined the variations of the microbial biomass. PMID:25699026

  18. Chemical and biological characterization of products of incomplete combustion from the simulated field burning of agricultural plastic

    SciTech Connect

    Linak, W.P.; Ryan, J.V.; Perry, E.; Williams, R.W.; DeMarini, D.M.

    1989-06-01

    Chemical and biological analyses were performed to characterize products of incomplete combustion emitted during the simulated open field burning of agricultural plastic. A small utility shed equipped with an air delivery system was used to simulate pile burning and forced-air-curtain incineration of a nonhalogenated agricultural plastic that reportedly consisted of polyethylene and carbon black. Emissions were analyzed for combustion gases; volatile, semi-volatile, and particulate organics; and toxic and mutagenic properties. Emission samples, as well as samples of the used (possibly pesticide-contaminated) plastic, were analyzed for the presence of several pesticides to which the plastic may have been exposed. Although a variety of alkanes, alkenes, and aromatic and polycyclic aromatic hydrocarbon (PAH) compounds were identified in the volatile, semi-volatile, and particulate fractions of these emissions, a substantial fraction of higher molecular weight organic material was not identified. No pesticides were identified in either combustion emission samples or dichloromethane washes of the used plastic. When mutagenicity was evaluated by exposing Salmonella bacteria (Ames assay) to whole vapor and vapor/particulate emissions, no toxic or mutagenic effects were observed. However, organic extracts of the particulate samples were moderately mutagenic. This mutagenicity compares approximately to that measured from residential wood heating on a revertant per unit heat release basis. Compared to pile burning, forced air slightly decreased the time necessary to burn a charge of plastic. There was not a substantial difference, however, in the variety or concentrations of organic compounds identified in samples from these two burn conditions. This study highlights the benefits of a combined chemical/biological approach to the characterization of complex, multi-component combustion emissions.

  19. Exposure to a heat wave under food limitation makes an agricultural insecticide lethal: a mechanistic laboratory experiment.

    PubMed

    Dinh, Khuong V; Janssens, Lizanne; Stoks, Robby

    2016-10-01

    Extreme temperatures and exposure to agricultural pesticides are becoming more frequent and intense under global change. Their combination may be especially problematic when animals suffer food limitation. We exposed Coenagrion puella damselfly larvae to a simulated heat wave combined with food limitation and subsequently to a widespread agricultural pesticide (chlorpyrifos) in an indoor laboratory experiment designed to obtain mechanistic insights in the direct effects of these stressors in isolation and when combined. The heat wave reduced immune function (activity of phenoloxidase, PO) and metabolic rate (activity of the electron transport system, ETS). Starvation had both immediate and delayed negative sublethal effects on growth rate and physiology (reductions in Hsp70 levels, total fat content, and activity levels of PO and ETS). Exposure to chlorpyrifos negatively affected all response variables. While the immediate effects of the heat wave were subtle, our results indicate the importance of delayed effects in shaping the total fitness impact of a heat wave when followed by pesticide exposure. Firstly, the combination of delayed negative effects of the heat wave and starvation, and the immediate negative effect of chlorpyrifos considerably (71%) reduced larval growth rate. Secondly and more strikingly, chlorpyrifos only caused considerable (ca. 48%) mortality in larvae that were previously exposed to the combination of the heat wave and starvation. This strong delayed synergism for mortality could be explained by the cumulative metabolic depression caused by each of these stressors. Further studies with increased realism are needed to evaluate the consequences of the here-identified delayed synergisms at the level of populations and communities. This is especially important as this synergism provides a novel explanation for the poorly understood potential of heat waves and of sublethal pesticide concentrations to cause mass mortality.

  20. Exposure to a heat wave under food limitation makes an agricultural insecticide lethal: a mechanistic laboratory experiment.

    PubMed

    Dinh, Khuong V; Janssens, Lizanne; Stoks, Robby

    2016-10-01

    Extreme temperatures and exposure to agricultural pesticides are becoming more frequent and intense under global change. Their combination may be especially problematic when animals suffer food limitation. We exposed Coenagrion puella damselfly larvae to a simulated heat wave combined with food limitation and subsequently to a widespread agricultural pesticide (chlorpyrifos) in an indoor laboratory experiment designed to obtain mechanistic insights in the direct effects of these stressors in isolation and when combined. The heat wave reduced immune function (activity of phenoloxidase, PO) and metabolic rate (activity of the electron transport system, ETS). Starvation had both immediate and delayed negative sublethal effects on growth rate and physiology (reductions in Hsp70 levels, total fat content, and activity levels of PO and ETS). Exposure to chlorpyrifos negatively affected all response variables. While the immediate effects of the heat wave were subtle, our results indicate the importance of delayed effects in shaping the total fitness impact of a heat wave when followed by pesticide exposure. Firstly, the combination of delayed negative effects of the heat wave and starvation, and the immediate negative effect of chlorpyrifos considerably (71%) reduced larval growth rate. Secondly and more strikingly, chlorpyrifos only caused considerable (ca. 48%) mortality in larvae that were previously exposed to the combination of the heat wave and starvation. This strong delayed synergism for mortality could be explained by the cumulative metabolic depression caused by each of these stressors. Further studies with increased realism are needed to evaluate the consequences of the here-identified delayed synergisms at the level of populations and communities. This is especially important as this synergism provides a novel explanation for the poorly understood potential of heat waves and of sublethal pesticide concentrations to cause mass mortality. PMID:27390895