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Sample records for agricultural areas nitrate

  1. Factors controlling nitrate fluxes in groundwater in agricultural areas

    USGS Publications Warehouse

    Liao, Lixia; Green, Christopher T.; Bekins, Barbara A.; Böhlke, J.K.

    2012-01-01

    The impact of agricultural chemicals on groundwater quality depends on the interactions of biogeochemical and hydrologic factors. To identify key processes affecting distribution of agricultural nitrate in groundwater, a parsimonious transport model was applied at 14 sites across the U.S. Simulated vertical profiles of NO3-, N2 from denitrification, O2, Cl-, and environmental tracers of groundwater age were matched to observations by adjusting the parameters for recharge rate, unsaturated zone travel time, fractions of N and Cl- inputs leached to groundwater, O2 reduction rate, O2 threshold for denitrification, and denitrification rate. Model results revealed important interactions among biogeochemical and physical factors. Chloride fluxes decreased between the land surface and water table possibly because of Cl- exports in harvested crops (averaging 22% of land-surface Cl- inputs). Modeled zero-order rates of O2 reduction and denitrification were correlated. Denitrification rates at depth commonly exceeded overlying O2 reduction rates, likely because shallow geologic sources of reactive electron donors had been depleted. Projections indicated continued downward migration of NO3- fronts at sites with denitrification rates -1 yr-1. The steady state depth of NO3- depended to a similar degree on application rate, leaching fraction, recharge, and NO3- and O2 reaction rates. Steady state total mass in each aquifer depended primarily on the N application rate. In addition to managing application rates at land surface, efficient water use may reduce the depth and mass of N in groundwater because lower recharge was associated with lower N fraction leached. Management actions to reduce N leaching could be targeted over aquifers with high-recharge and low-denitrification rates.

  2. Monitoring of nitrates in drinking water from agricultural and residential areas of Podravina and Prigorje (Croatia).

    PubMed

    Nemčić-Jurec, Jasna; Konjačić, Miljenko; Jazbec, Anamarija

    2013-11-01

    Nitrates are the most common chemical pollutant of groundwater in agricultural and suburban areas. Croatia must comply with the Nitrate Directive (91/676/EEC) whose aim is to reduce water pollution by nitrates originating from agriculture and to prevent further pollution. Podravina and Prigorje are the areas with a relatively high degree of agricultural activity. Therefore, the aim of this study was, by monitoring nitrates, to determine the distribution of nitrates in two different areas, Podravina and Prigorje (Croatia), to determine sources of contamination as well as annual and seasonal trends. The nitrate concentrations were measured in 30 wells (N = 382 samples) in Prigorje and in 19 wells (N = 174 samples) in Podravina from 2002 to 2007. In Podravina, the nitrate content was 24.9 mg/l and 6% of the samples were above the maximum available value (MAV), and in Prigorje the content was 53.9 mg/l and 38% of the samples above MAV. The wells were classified as correct, occasionally incorrect and incorrect. In the group of occasionally incorrect and incorrect wells, the point sources were within 10 m of the well. There is no statistically significant difference over the years or seasons within the year, but the interaction between locations and years was significant. Nitrate concentrations' trend was not significant during the monitoring. These results are a prerequisite for the adjustment of Croatian standards to those of the EU and will contribute to the implementation of the Nitrate Directive and the Directives on Environmental Protection in Croatia and the EU.

  3. Source identification of nitrate in groundwater using stable isotopes and Cl/Br ratios in an agricultural area

    NASA Astrophysics Data System (ADS)

    Koh, D.; Mayer, B.

    2009-12-01

    Sources of nitrate in groundwater were investigated in an agricultural area with natural area at higher altitude, upland at hilly terrains and residential areas at low-lying lands using δ15N and δ18O of nitrate and Cl/Br ratios. The NO3- concentration in groundwater was as high as 49 mg/L, with an average of 6.0 mg/L and a median value of 4.4 mg/L as NO3-N, and, 22% of the groundwater samples exceeded the DWS of South Korea, which is 10 mg/L for NO3-N. Nitrate sources were consistently identified in residential and upland areas using stable isotopes of nitrate and Cl/Br ratios which showed that the higher δ15N-NO3- and Cl/Br ratios in residential area and lower δ15N-NO3- and Cl/Br ratios in upland Meanwhile, contribution of atmospheric nitrate in natural area was not readily observable due to resetting of δ18O-NO3- in the soil zone. The higher δ15N-NO3- values in residential area was consistent with higher Cl/Br ratios indicating the effect of domestic wastewater including sewage and septic effluents. Upland area had δ15N-NO3- corresponding to soil organic nitrogen which seems resulted from mixed sources of mineralized fertilizer and manure with higher contribution of the latter. The lower Cl/Br ratios of upland area compared to residential area indicates higher contribution of agrochemicals including fertilizers and pesticides. Statistical comparison of chemical and isotopic parameters according to land-use groups revealed that nitrate concentrations and Cl/Br ratios were distinctive between four land uses considered whereas stable isotopes of nitrate were not significantly different between anthropogenic land uses indicating Cl/Br ratio is a more efficient tracer for impact of land-uses on groundwater quality in agricultural areas.

  4. 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

  5. Nitrate concentrations under irrigated agriculture

    USGS Publications Warehouse

    Zaporozec, A.

    1983-01-01

    In recent years, considerable interest has been expressed in the nitrate content of water supplies. The most notable toxic effect of nitrate is infant methemoglobinemia. The risk of this disease increases significantly at nitrate-nitrogen levels exceeding 10 mg/l. For this reason, this concentration has been established as a limit for drinking water in many countries. In natural waters, nitrate is a minor ionic constituent and seldom accounts for more than a few percent of the total anions. However, nitrate in a significant concentration may occur in the vicinity of some point sources such as septic tanks, manure pits, and waste-disposal sites. Non-point sources contributing to groundwater pollution are numerous and a majority of them are related to agricultural activities. The largest single anthropogenic input of nitrate into the groundwater is fertilizer. Even though it has not been proven that nitrogen fertilizers are responsible for much of nitrate pollution, they are generally recognized as the main threat to groundwater quality, especially when inefficiently applied to irrigated fields on sandy soils. The biggest challenge facing today's agriculture is to maintain the balance between the enhancement of crop productivity and the risk of groundwater pollution. ?? 1982 Springer-Verlag New York Inc.

  6. Linking Groundwater Age and Chemistry Data to Determine Redox Reaction Rates and Trends in Nitrate Concentrations in Agricultural Areas. (Invited)

    NASA Astrophysics Data System (ADS)

    Tesoriero, A. J.; Puckett, L.

    2009-12-01

    Use of industrially fixed nitrogen (N) fertilizer for agricultural purposes has increased dramatically, both in the United States (U.S.) and globally, since 1945. As a result, there has been growing concern about the consequences of increases in the amounts of anthropogenic N circulating in the atmosphere, hydrosphere, and biosphere. The U.S. Geological Survey’s National Water-Quality Assessment Program has collected groundwater samples along flow paths in more than 20 agricultural areas covering a range in hydrogeologic settings to evaluate the trends and transformations of agricultural chemicals. Historical trends in nitrogen fluxes to groundwater were evaluated by relating the recharge dates of groundwater samples, estimated using tracer (e.g., chlorofluorocarbon) concentrations, with concentrations of nitrate at the time of recharge, estimated by summing the molar concentrations of the parent compound (nitrate) and its transformation product (excess N2) in the age-dated sample. Results from this analysis indicate that median nitrate (NO3-) concentrations in recharge have increased markedly over the last 50 years: increasing from 4 mg/L (as N) in samples that recharged prior to 1983 to 7.5 mg/L (as N) in samples that recharged since 1983. Trends in nitrate concentrations in recharging groundwater were related to increases in the amount of fertilizer applied. Estimates of the portion of applied N reaching the water table ranged from 4 to 49% among the sites, with a median value of 14%. The fate of NO3- and many other groundwater contaminants is dependent on aquifer redox conditions. The reduction of oxygen is the most energetically favorable reaction that microorganisms use to oxidize organic material or other electron donors (e.g., pyrite). As a result, other reduction reactions (e.g., denitrification) affecting contaminant transport typically do not occur until most dissolved oxygen (DO) has been consumed. To improve assessments of contaminant transformations

  7. Assessment of sources and fate of nitrate in shallow groundwater of an agricultural area by using a multi-tracer approach.

    PubMed

    Pastén-Zapata, Ernesto; Ledesma-Ruiz, Rogelio; Harter, Thomas; Ramírez, Aldo I; Mahlknecht, Jürgen

    2014-02-01

    Nitrate isotopic values are often used as a tool to understand sources of contamination in order to effectively manage groundwater quality. However, recent literature describes that biogeochemical reactions may modify these values. Therefore, data interpretation is difficult and often vague. We provide a discussion on this topic and complement the study using halides as comparative tracers assessing an aquifer underneath a sub-humid to humid region in NE Mexico. Hydrogeological information and stable water isotopes indicate that active groundwater recharge occurs in the 8000km(2) study area under present-day climatic and hydrologic conditions. Nitrate isotopes and halide ratios indicate a diverse mix of nitrate sources and transformations. Nitrate sources include organic waste and wastewater, synthetic fertilizers and soil processes. Animal manure and sewage from septic tanks were the causes of groundwater nitrate pollution within orchards and vegetable agriculture. Dairy activities within a radius of 1,000 m from a sampling point significantly contributed to nitrate pollution. Leachates from septic tanks caused nitrate pollution in residential areas. Soil nitrogen and animal waste were the sources of nitrate in groundwater under shrubland and grassland. Partial denitrification processes helped to attenuate nitrate concentration underneath agricultural lands and grassland, especially during summer months. PMID:24200723

  8. Assessment of sources and fate of nitrate in shallow groundwater of an agricultural area by using a multi-tracer approach.

    PubMed

    Pastén-Zapata, Ernesto; Ledesma-Ruiz, Rogelio; Harter, Thomas; Ramírez, Aldo I; Mahlknecht, Jürgen

    2014-02-01

    Nitrate isotopic values are often used as a tool to understand sources of contamination in order to effectively manage groundwater quality. However, recent literature describes that biogeochemical reactions may modify these values. Therefore, data interpretation is difficult and often vague. We provide a discussion on this topic and complement the study using halides as comparative tracers assessing an aquifer underneath a sub-humid to humid region in NE Mexico. Hydrogeological information and stable water isotopes indicate that active groundwater recharge occurs in the 8000km(2) study area under present-day climatic and hydrologic conditions. Nitrate isotopes and halide ratios indicate a diverse mix of nitrate sources and transformations. Nitrate sources include organic waste and wastewater, synthetic fertilizers and soil processes. Animal manure and sewage from septic tanks were the causes of groundwater nitrate pollution within orchards and vegetable agriculture. Dairy activities within a radius of 1,000 m from a sampling point significantly contributed to nitrate pollution. Leachates from septic tanks caused nitrate pollution in residential areas. Soil nitrogen and animal waste were the sources of nitrate in groundwater under shrubland and grassland. Partial denitrification processes helped to attenuate nitrate concentration underneath agricultural lands and grassland, especially during summer months.

  9. Temporal analysis of spring water data to assess nitrate inputs to groundwater in an agricultural area (Osona, NE Spain).

    PubMed

    Boy-Roura, Mercè; Menció, Anna; Mas-Pla, Josep

    2013-05-01

    Non-point agricultural pollution is a major concern in groundwater management. To investigate nitrate input to the subsurface through groundwater recharge, thirteen natural springs were sampled. Discharge, electrical conductivity (EC), nitrate concentration, pH value and water temperature were monitored every two weeks from January 2010 till February 2011 at selected springs in the Osona region (NE Spain). Two extensive hydrochemical analyses were also conducted at the beginning and at the end of the survey. Springs are classified in four groups describing their hydrological response, based on discharge, EC and nitrate data. Geostatistical analysis provides an additional insight into the discharge and nitrate temporal pattern. Even though discharge and EC can be related to specific hydrogeological behaviours, nitrate content shows uniform values in most of the springs with only a minor influence from external factors such as rainfall events, fertilisation regimes and geological traits. Such evenness of outflow might be attributed to a homogenisation of the subsurface processes that determine nitrate infiltration after decades of intensive fertilisation using pig manure. Accumulated nitrate mass load and variograms confirm this result. Assuming that spring data are representative of nitrate leaching towards the underlying aquifer, nitrate content of infiltrating recharge in shallow aquifers should therefore show a steady value over time with only small fluctuations due to natural processes. Nevertheless, temporal fluctuations in nitrate content in aquifers could be also attributed to flow regime alterations due to human groundwater withdrawal.

  10. Nitrate in aquifers beneath agricultural systems

    USGS Publications Warehouse

    Burkart, M.R.; Stoner, J.D.; ,

    2007-01-01

    Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWQA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and also shallow carbonate aquifers that provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The system of corn, soybean, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems because this system imports the largest amount of N-fertilizer per unit production area. Mean nitrate under dairy, poultry, horticulture, and cattle and grains systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as

  11. Nitrate in aquifers beneath agricultural systems.

    PubMed

    Burkart, M R; Stoner, J D

    2007-01-01

    Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWQA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and also shallow carbonate aquifers that provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The system of corn, soybean, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems because this system imports the largest amount of N-fertilizer per unit production area. Mean nitrate under dairy, poultry, horticulture, and cattle and grains systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as

  12. Delimitation of areas under the real pressure from agricultural activities due to nitrate water pollution in Poland

    NASA Astrophysics Data System (ADS)

    Wozniak, E.; Nasilowska, S.; Jarocinska, A.; Igras, J.; Stolarska, M.; Bernoussi, A. S.; Karaczun, Z.

    2012-04-01

    The aim of the performed research was to determine catchments under the nitrogen pressure in Poland in period of 2007-2010. National Water Management Authority in Poland uses the elaborated methodology to fulfil requirements of Nitrate Directive and Water Framework Directive. Multicriteria GIS analysis was conducted on the base on various types of environmental data, maps and remote sensing products. Final model of real agricultural pressure was made using two components: (i) potential pressure connected with agriculture (ii) the vulnerability of the area. The agricultural pressure was calculated using the amount of nitrogen in fertilizers and the amount of nitrogen produced by animal breeding. The animal pressure was based on the information about the number of bred animals of each species for communes in Poland. The spatial distribution of vegetation pressure was calculated using kriging for the whole country base on the information about 5000 points with the amount of nitrogen dose in fertilizers. The vulnerability model was elaborated only for arable lands. It was based on the probability of the precipitation penetration to the ground water and runoff to surface waters. Catchment, Hydrogeological, Soil, Relief or Land Cover maps allowed taking into account constant environmental conditions. Additionally information about precipitation for each day of analysis and evapotranspiration for every 16-day period (calculated from satellite images) were used to present influence of meteorological condition on vulnerability of the terrain. The risk model is the sum of the vulnerability model and the agricultural pressure model. In order to check the accuracy of the elaborated model, the authors compared the results with the eutrophication measurements. The model accuracy is from 85,3% to 91,3%.

  13. Nitrate in aquifers beneath agricultural systems

    USGS Publications Warehouse

    Burkart, M.R.; Stoner, J.D.

    2002-01-01

    Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWOA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and shallow carbonate aquifers provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The agricultural system of corn, soybeans, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems, although mean nitrate concentrations in counties with dairy, poultry, cattle and grains, and horticulture systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as in Asia, may experience the greatest impact of

  14. Nitrate in aquifers beneath agricultural systems.

    PubMed

    Burkart, M R; Stoner, J D

    2002-01-01

    Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWOA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and shallow carbonate aquifers provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional concentrations of groundwater nitrate than all other agricultural systems, although mean nitrate concentrations in counties with dairy, poultry, cattle and grains, and horticulture systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as in Asia, may experience the greatest impact of this practice.

  15. Land-use controls on sources and fate of nitrate in shallow groundwater of an agricultural area revealed by multiple environmental tracers

    NASA Astrophysics Data System (ADS)

    Koh, Dong-Chan; Mayer, Bernhard; Lee, Kwang-Sik; Ko, Kyung-Seok,

    2010-10-01

    Sources and transformation processes of nitrate in groundwater from shallow aquifers were investigated in an agricultural area in the mid-western part of South Korea using a multi-tracer approach including δ 2H and δ 18O values of water, δ 15N and δ 18O values of nitrate, Cl/Br ratios and chlorofluorocarbons (CFCs). The study area was comprised of four land-use types with natural areas at higher altitudes, upland areas with fruit orchards, paddy fields and residential areas at lower elevations. The isotopic composition of water was suitable for distinguishing groundwater that had infiltrated in the higher elevation natural areas with lower δ 2H and δ 18O values from groundwater underneath paddy fields that was characterized by elevated δ 2H and δ 18O values due to evaporation. δ 18O-H 2O values and Cl - concentrations indicated that groundwater and contaminant sources were derived from three land-use types: natural areas, residential areas and paddy fields. Groundwater age determination based on CFCs showed that nitrate contamination of groundwater is primarily controlled by historic nitrogen loadings at least in areas with higher nitrate contamination. Nitrate sources were identified using the stable isotope composition of nitrate and Cl/Br ratios. Higher δ 15N-NO 3- values and Cl/Br ratios of 300 to 800 in residential areas indicated that waste water and septic effluents were major nitrate sources whereas lower δ 15N-NO 3- values and Cl/Br ratios of 100 to 700 in upland areas suggested that synthetic fertilizers constituted a major source of nitrate contamination of aquifers. With only few exceptions in the natural area, contributions of atmospheric nitrate were insignificant due to the resetting of δ 18O-NO 3- values via immobilization and re-mineralization of nitrate in the soil zone. In groundwater underneath paddy fields, 30% of samples had δ 18O-NO 3- values at least 2‰ higher than expected for nitrate formed by chemolithoautotrophic

  16. Land-use controls on sources and fate of nitrate in shallow groundwater of an agricultural area revealed by multiple environmental tracers.

    PubMed

    Koh, Dong-Chan; Mayer, Bernhard; Lee, Kwang-Sik; Ko, Kyung-Seok

    2010-10-21

    Sources and transformation processes of nitrate in groundwater from shallow aquifers were investigated in an agricultural area in the mid-western part of South Korea using a multi-tracer approach including δ²H and δ¹⁸O values of water, δ¹⁵N and δ¹⁸O values of nitrate, Cl/Br ratios and chlorofluorocarbons (CFCs). The study area was comprised of four land-use types with natural areas at higher altitudes, upland areas with fruit orchards, paddy fields and residential areas at lower elevations. The isotopic composition of water was suitable for distinguishing groundwater that had infiltrated in the higher elevation natural areas with lower δ²H and δ¹⁸O values from groundwater underneath paddy fields that was characterized by elevated δ²H and δ¹⁸O values due to evaporation. δ¹⁸O-H₂O values and Cl⁻ concentrations indicated that groundwater and contaminant sources were derived from three land-use types: natural areas, residential areas and paddy fields. Groundwater age determination based on CFCs showed that nitrate contamination of groundwater is primarily controlled by historic nitrogen loadings at least in areas with higher nitrate contamination. Nitrate sources were identified using the stable isotope composition of nitrate and Cl/Br ratios. Higher δ¹⁵N-NO₃⁻ values and Cl/Br ratios of 300 to 800 in residential areas indicated that waste water and septic effluents were major nitrate sources whereas lower δ¹⁵N-NO₃⁻ values and Cl/Br ratios of 100 to 700 in upland areas suggested that synthetic fertilizers constituted a major source of nitrate contamination of aquifers. With only few exceptions in the natural area, contributions of atmospheric nitrate were insignificant due to the resetting of δ¹⁸O-NO₃⁻ values via immobilization and re-mineralization of nitrate in the soil zone. In groundwater underneath paddy fields, 30% of samples had δ¹⁸O-NO₃⁻ values at least 2‰ higher than expected for nitrate formed

  17. Indicators of the sources and distribution of nitrate in water from shallow domestic wells in agricultural areas of the New Jersey Coastal Plain

    USGS Publications Warehouse

    Vowinkel, Eric F.; Tapper, Robert J.

    1995-01-01

    Previously collected and new water-quality data from shallow wells (screened interval less than 30 meters below the land surface) in predominantly agricultural areas of the New Jersey Coastal Plain were used to determine the relation of nitrate concentrations in shallow ground water to various hydrogeologic and land-use factors in the study area. Information on land use, well construction, hydrogeology, and water quality were used to predict the conditions under which concentrations of nitrate as nitrogen in water from domestic wells in predominantly agricultural areas are most likely to be equal to or larger than the U.S. Environmental Protection Agency maximum contaminant level (MCL) of 10 milligrams per liter. Results of the analyses of water-quality samples collected during 1980-89 from 230 shallow wells in the outcrop areas of the Kirkwood-Cohansey and Potomac-Raritan-Magothy aquifer systems were used to evaluate the regional effects of land use on shallow-ground-water quality. Results of statistical analysis indicate that concentrations of nitrate in shallow ground water are significantly different (p= 0.001) in agricultural areas than in undeveloped areas in both aquifer systems. Concentrations of nitrate nitrogen exceeded the MCL in water from more than 33 percent of the 60 shallow wells in agricultural areas. Concentrations of hitrate in water from shallow wells in agricultural areas increased as the percentage of agricultural land within an 800-meter-radius buffer zone of the wellhead increased (r= 0.81). Concentrations ofhitrate in water from domestic wells in agricultural areas were similar (p= 0.23) to those concentrations in water from irrigation wells. These results indicate that most of the nitrate in water from domestic wells in agricultural areas results from agricultural practices rather than other sources, such as septic systems. Water-quality samples collected from 12 shallow domestic wells in agricultural areas screened in the outcrop areas of

  18. Factors affecting the movement and persistence of nitrate and pesticides in the surficial and upper Floridan aquifers in two agricultural areas in the southeastern United States

    USGS Publications Warehouse

    Katz, B.G.; Berndt, M.P.; Crandall, C.A.

    2014-01-01

    Differences in the degree of confinement, redox conditions, and dissolved organic carbon (DOC) are the main factors that control the persistence of nitrate and pesticides in the Upper Floridan aquifer (UFA) and overlying surficial aquifer beneath two agricultural areas in the southeastern US. Groundwater samples were collected multiple times from 66 wells during 1993–2007 in a study area in southwestern Georgia (ACFB) and from 48 wells in 1997–98 and 2007–08 in a study area in South Carolina (SANT) as part of the US Geological Survey National Water-Quality Assessment Program. In the ACFB study area, where karst features are prevalent, elevated nitrate-N concentrations in the oxic unconfined UFA (median 2.5 mg/L) were significantly (p = 0.03) higher than those in the overlying oxic surficial aquifer (median 1.5 mg/L). Concentrations of atrazine and deethylatrazine (DEA; the most frequently detected pesticide and degradate) were higher in more recent groundwater samples from the ACFB study area than in samples collected prior to 2000. Conversely, in the SANT study area, nitrate-N concentrations in the UFA were mostly <0.06 mg/L, resulting from anoxic conditions and elevated DOC concentrations that favored denitrification. Although most parts of the partially confined UFA in the SANT study area were anoxic or had mixed redox conditions, water from 28 % of the sampled wells was oxic and had low DOC concentrations. Based on the groundwater age information, nitrate concentrations reflect historic fertilizer N usage in both the study areas, but with a lag time of about 15–20 years. Simulated responses to future management scenarios of fertilizer N inputs indicated that elevated nitrate-N concentrations would likely persist in oxic parts of the surficial aquifer and UFA for decades even with substantial decreases in fertilizer N inputs over the next 40 years.

  19. Identification of groundwater contamination sources of nitrate and sulfate in shallow alluvial aquifers using a dual-isotope approach in an agricultural area

    NASA Astrophysics Data System (ADS)

    Kaown, D.; Koh, D.; Mayer, B.; Hyun, Y.; Bae, G.; Lee, K.

    2007-12-01

    The elevated level of nitrate in groundwater is a serious problem in Korean agricultural areas. Yupori, a small agricultural area in Chuncheon (Korea), shows a rising level of NO3-N and displays multiple NO3-N sources from non-point and point sources in shallow aquifer groundwater. Numerous vegetable fields are located in the western part of the study area and fruit orchards dominate the landscape with only few vegetable fields in the eastern part of the study area. The source identification of groundwater contamination from overburden agricultural area was undertaken by analyzing hydrochemical data and stable isotopic compositions of dissolved nitrate and sulfate (¥ä15N-NO3-, ¥ä18O-NO3-, ¥ä34S-SO42-, and ¥ä18O-SO42-). The measurements of ¥ä15N- NO3- are in the range of 7.1 to 14.4¢¶ and the values of ¥ä18O-NO3- are in the range of -1.8 to 6.5¢¶. High ¥ä15N-NO3- values shown at low concentrations of nitrate in the eastern Yupori are characteristics of manure- derived nitrate and organic soil. The values of ¥ä34S-SO4-2 ranged from 2.9 to 9.9¢¶ and ¥ä18O-SO42- ranged from 2.5 to 4.7¢¶. At high concentrations of SO42- in the western Yupori, the value of ¥ä34S-SO42- are low around 3-4¢¶. The value of ¥ä34S-SO42- increased with decreasing SO42- concentration in the eastern Yupori. Groundwater quality and stable isotopic compositions of dissolved nitrate and sulfate seem to be significantly affected by agricultural land use pattern of the study site.

  20. Sustainability of natural attenuation of nitrate in agricultural aquifers

    USGS Publications Warehouse

    Green, Christopher T.; Bekins, Barbara A.

    2010-01-01

    Increased concentrations of nitrate in groundwater in agricultural areas, coinciding with increased use of chemical and organic fertilizers, have raised concern because of risks to environmental and human health. At some sites, these problems are mitigated by natural attenuation of nitrate as a result of microbially mediated reactions. Results from U.S. Geological Survey (USGS) research under the National Water-Quality Assessment (NAWQA) program show that reactions of dissolved nitrate with solid aquifer minerals and organic carbon help lower nitrate concentrations in groundwater beneath agricultural fields. However, increased fluxes of nitrate cause ongoing depletion of the finite pool of solid reactants. Consumption of the solid reactants diminishes the capacity of the aquifer to remove nitrate, calling into question the long-term sustainability of these natural attenuation processes.

  1. Denitrification in the recharge area and discharge area of a transient agricultural nitrate plume in a glacial outwash sand aquifer, Minnesota

    USGS Publications Warehouse

    Böhlke, J.K.; Wanty, R.; Tuttle, M.; Delin, G.; Landon, M.

    2002-01-01

    Recharge rates of nitrate (NO3-) to groundwater beneath agricultural land commonly are greater than discharge rates of NO3- in nearby streams, but local controls of NO3- distribution in the subsurface generally are poorly known. Groundwater dating (CFC, 3H) was combined with chemical (ions and gases) and stable isotope (N, S, and C) analyses to resolve the effects of land use changes, flow patterns, and water-aquifer reactions on the distributions of O2, NO3-, SO4=, and other constituents in a two-dimensional vertical section leading from upland cultivated fields to a riparian wetland and stream in a glacial outwash sand aquifer near Princeton, Minnesota. Within this section a "plume" of oxic NO3--rich groundwater was present at shallow depths beneath the fields and part of the wetland but terminated before reaching the stream or the wetland surface. Groundwater dating and hydraulic measurements indicate travel times in the local flow system of 0 to >40 years, with stratified recharge beneath the fields, downward diversion of the shallow NO3--bearing plume by semiconfining organic-rich valley-filling sediments under the wetland and upward discharge across the valley and stream bottom. The concentrations and ??15N values of NO3- and N2 indicate that the NO3- plume section was bounded in three directions by a curvilinear zone of active denitrification that limited its progress; however, when recalculated to remove the effects of denitrification, the data also indicate changes in both the concentrations and ??15N values of NO3- that was recharged in the past. Isotope data and mass balance calculations indicate that FeS2 and other ferrous Fe phases were the major electron donors for denitrification in at least two settings: (1) within the glacial-fluvial aquifer sediments beneath the recharge and discharge areas and (2) along the bottom of the valley-filling sediments in the discharge area. Combined results indicate that the shape and progress of the oxic NO3- plume

  2. Identifying the sources of nitrate contamination of groundwater in an agricultural area (Haean basin, Korea) using isotope and microbial community analyses.

    PubMed

    Kim, Heejung; Kaown, Dugin; Mayer, Bernhard; Lee, Jin-Yong; Hyun, Yunjung; Lee, Kang-Kun

    2015-11-15

    An integrated study based on hydrogeochemical, microbiological and dual isotopic approaches for nitrate and sulfate was conducted to elucidate sources and biogeochemical reactions governing groundwater contaminants in different seasons and under different land use in a basin of Korea. The land use in the study area is comprised of forests (58.0%), vegetable fields (27.6%), rice paddy fields (11.4%) and others (3.0%). The concentrations of NO3-N and SO4(2-) in groundwater in vegetable fields were highest with 4.2-15.2 mg L(-1) and 1.6-19.7 mg L(-1) respectively, whereas under paddy fields NO3-N concentrations ranged from 0 to 10.7 mg L(-1) and sulfate concentrations were ~15 mg L(-1). Groundwater with high NO3-N concentrations of >10mgL(-1) had δ(15)N-NO3(-) values ranging from 5.2 to 5.9‰ and δ(18)O values of nitrate between 2.7 and 4.6‰ suggesting that the nitrate was mineralized from soil organic matter that was amended by fertilizer additions. Elevated concentrations of SO4(2-) with δ(34)S-SO4(2-) values between 1 and 6‰ in aquifers in vegetable fields indicated that a mixture of sulfate from atmospheric deposition, mineralization of soil organic matter and from synthetic fertilizers is the source of groundwater sulfate. Elevated δ(18)O-NO3(-) and δ(18)O-SO4(2-) values in samples collected from the paddy fields indicated that denitrification and bacterial sulfate reduction are actively occurring removing sulfate and nitrate from the groundwater. This was supported by high occurrences of denitrifying and sulfate reducing bacteria in groundwater of the paddy fields as evidenced by 16S rRNA pyrosequencing analysis. This study shows that dual isotope techniques combined with microbial data can be a powerful tool for identification of sources and microbial processes affecting NO3(-) and SO4(2-) in groundwater in areas with intensive agricultural land use. PMID:26204420

  3. Identifying the sources of nitrate contamination of groundwater in an agricultural area (Haean basin, Korea) using isotope and microbial community analyses.

    PubMed

    Kim, Heejung; Kaown, Dugin; Mayer, Bernhard; Lee, Jin-Yong; Hyun, Yunjung; Lee, Kang-Kun

    2015-11-15

    An integrated study based on hydrogeochemical, microbiological and dual isotopic approaches for nitrate and sulfate was conducted to elucidate sources and biogeochemical reactions governing groundwater contaminants in different seasons and under different land use in a basin of Korea. The land use in the study area is comprised of forests (58.0%), vegetable fields (27.6%), rice paddy fields (11.4%) and others (3.0%). The concentrations of NO3-N and SO4(2-) in groundwater in vegetable fields were highest with 4.2-15.2 mg L(-1) and 1.6-19.7 mg L(-1) respectively, whereas under paddy fields NO3-N concentrations ranged from 0 to 10.7 mg L(-1) and sulfate concentrations were ~15 mg L(-1). Groundwater with high NO3-N concentrations of >10mgL(-1) had δ(15)N-NO3(-) values ranging from 5.2 to 5.9‰ and δ(18)O values of nitrate between 2.7 and 4.6‰ suggesting that the nitrate was mineralized from soil organic matter that was amended by fertilizer additions. Elevated concentrations of SO4(2-) with δ(34)S-SO4(2-) values between 1 and 6‰ in aquifers in vegetable fields indicated that a mixture of sulfate from atmospheric deposition, mineralization of soil organic matter and from synthetic fertilizers is the source of groundwater sulfate. Elevated δ(18)O-NO3(-) and δ(18)O-SO4(2-) values in samples collected from the paddy fields indicated that denitrification and bacterial sulfate reduction are actively occurring removing sulfate and nitrate from the groundwater. This was supported by high occurrences of denitrifying and sulfate reducing bacteria in groundwater of the paddy fields as evidenced by 16S rRNA pyrosequencing analysis. This study shows that dual isotope techniques combined with microbial data can be a powerful tool for identification of sources and microbial processes affecting NO3(-) and SO4(2-) in groundwater in areas with intensive agricultural land use.

  4. Managing ground-water contamination from agricultural nitrates

    SciTech Connect

    Halstead, J.M.

    1989-01-01

    Ground-water contamination from agricultural nitrates poses potential adverse health effects to a large segment of the rural population of the United States. Contamination is especially prevalent in livestock intensive areas, which produce large quantities of animal waste with substantial nitrogen content. In this study, potential management strategies for reducing nitrate contamination of ground water from agricultural sources were examined using an economic-physical model of representative dairy farm in Rockingham County, Virginia. A mixed-integer programming model with stochastic constraints on nitrate loading to ground water and silage production was used. Results of the model indicate that substantial reductions in current nitrate loadings are possible with relatively minor impacts on farmers' net returns through the use of currently practiced approaches of cost sharing for manure storage facility construction and nutrient management planning. Study results indicate that a wide range of policy options exist for reducing nitrate loading to ground water; these reductions, while varying in cost, do no appear to come at the expense of eliminating the economic viability of the county dairy sector.

  5. Nitrate from agriculture: moving from uncertain data to operational responses

    NASA Astrophysics Data System (ADS)

    Hart, Alwyn; Bieroza, Magdalena

    2015-04-01

    The Nitrates Directive (91/676/EEC) is designed to protect waters against nitrate pollution from agricultural sources. It requires Member States to identify waters which are, or could become, polluted by nitrates and to designate as Nitrate Vulnerable Zones (NVZs) all land draining to those waters and contributing to the pollution. To meet these requirements, Department for Environment Food & Rural Affairs (Defra) have commissioned reviews that designated NVZs in 1993, 1998, 2002, 2008 and 2013. The designation methods used have evolved over this time and have been developed with the close involvement of farming and water company representatives and with advice and guidance from a number of independent external technical experts. The monitoring network and methods change frequently and methods need to be developed which are robust enough to cope with gaps in data, both geographical and temporal. This project is aimed at investigating new approaches for identifying waters that are at risk of nitrate pollution and the land that drains to these and builds on a large body of evidence supporting understanding of nitrate in the environment. The work will demonstrate to Defra and to the wider community that the most cost efficient and appropriate methods to designate NVZ areas for groundwater and surface water are used.

  6. Long-term fate of nitrate fertilizer in agricultural soils.

    PubMed

    Sebilo, Mathieu; Mayer, Bernhard; Nicolardot, Bernard; Pinay, Gilles; Mariotti, André

    2013-11-01

    Increasing diffuse nitrate loading of surface waters and groundwater has emerged as a major problem in many agricultural areas of the world, resulting in contamination of drinking water resources in aquifers as well as eutrophication of freshwaters and coastal marine ecosystems. Although empirical correlations between application rates of N fertilizers to agricultural soils and nitrate contamination of adjacent hydrological systems have been demonstrated, the transit times of fertilizer N in the pedosphere-hydrosphere system are poorly understood. We investigated the fate of isotopically labeled nitrogen fertilizers in a three-decade-long in situ tracer experiment that quantified not only fertilizer N uptake by plants and retention in soils, but also determined to which extent and over which time periods fertilizer N stored in soil organic matter is rereleased for either uptake in crops or export into the hydrosphere. We found that 61-65% of the applied fertilizers N were taken up by plants, whereas 12-15% of the labeled fertilizer N were still residing in the soil organic matter more than a quarter century after tracer application. Between 8-12% of the applied fertilizer had leaked toward the hydrosphere during the 30-y observation period. We predict that additional exports of (15)N-labeled nitrate from the tracer application in 1982 toward the hydrosphere will continue for at least another five decades. Therefore, attempts to reduce agricultural nitrate contamination of aquatic systems must consider the long-term legacy of past applications of synthetic fertilizers in agricultural systems and the nitrogen retention capacity of agricultural soils.

  7. Evaluation of Nitrate Sources and Nitrate Management Strategies in California Suburban Growth Areas

    NASA Astrophysics Data System (ADS)

    Singleton, M. J.; Moran, J. E.; Esser, B. K.; Leif, R. N.; McNab, W. W.; Carle, S. F.; Moore, K. B.

    2005-12-01

    Population growth in California has pushed the boundaries of suburban communities into formerly agricultural areas. As a result there is considerable uncertainty as to whether nitrate contamination in groundwater wells results from current sources or is a legacy of agriculture. Fertilizer application for historical agriculture is frequently assumed to be a major source, but septic system leachate, other animal waste, and residential fertilizer application may also contribute. Potential remediation strategies may include improved fertilizer management and/or conversion from septic tanks to sewer systems, but the sources of nitrate and pathways to groundwater must first be identified in order to develop a plan of action. We combine the detection of trace organic compounds that are specific to domestic waste with isotopic compositions of nitrogen and oxygen in nitrate in order to determine nitrate sources. Under anaerobic conditions and in the presence of an electron donor such as organic carbon, microbially mediated denitrification may transform nitrate to harmless nitrogen gas, and fractionate the isotopologues of any residual nitrate. The occurrence of saturated zone denitrification is detected by measuring excess dissolved nitrogen gas with a field-portable membrane inlet mass spectrometer system. Groundwater age dating using the 3H/3He method provides a means of tracking the history of nitrate inputs to groundwater, including changes in nitrate flux after implementation of a remediation program. Groundwater that pre-dates agricultural or suburban activity is used to define natural background levels of nitrate. Study areas in California include Chico, Livermore, and Gilroy. This work was performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

  8. Effects of groundwater residence time and recharge rate on nitrate contamination deduced from δ18O, δD, 3H/ 3He and CFCs in a small agricultural area in Chuncheon, Korea

    NASA Astrophysics Data System (ADS)

    Kaown, Dugin; Koh, Dong-Chan; Lee, Kang-Kun

    2009-03-01

    SummaryStable isotopes of water, chlorofluorocarbon (CFCs), and 3H/ 3He were applied in combination with hydrogeochemical data to analyze recharge patterns and nitrate contamination of shallow groundwater systems in a small agricultural area, Yupori, Chuncheon (Korea), where the eastern part is on hill slopes and the western part is low lands. The values of δ18O and δD indicated that groundwater is derived mainly from summer precipitation, which is more pronounced in the western part than in the eastern part. The apparent groundwater ages using CFC-113 and 3H/ 3He ranged from 13 to 31 yr, and are younger in the western part than in the eastern part. Dispersion models fit concentrations of 3H and CFC-113 for most wells of the eastern part with intermediate dispersion parameters. Nitrate concentrations were higher in the western part than the eastern part due to the land use pattern and topography. Stable isotopes of water and groundwater ages indicated that higher recharge rate affected by multiple sources of contamination is dominant in the western part whereas limited recharge with weak nitrate sources is considerable in the eastern part. This groundwater flow pattern corresponds to the different nitrate concentrations in the western and the eastern part. Groundwater residence time and recharge rate play an important role in the spatial distribution of NO 3 concentration in the study area as well as land use pattern.

  9. Controlling nitrate leaching in irrigated agriculture.

    PubMed

    Spalding, R F; Watts, D G; Schepers, J S; Burbach, M E; Exner, M E; Poreda, R J; Martin, G E

    2001-01-01

    The impact of improved irrigation and nutrient practices on ground water quality was assessed at the Nebraska Management System Evaluation Area using ground water quality data collected from 16 depths at 31 strategically located multilevel samplers three times annually from 1991 to 1996. The site was sectioned into four 13.4-ha management fields: (i) a conventional furrow-irrigated corn (Zea mays L.) field; (ii) a surge-irrigated corn field, which received 60% less water and 31% less N fertilizer than the conventional field; (iii) a center pivot-irrigated corn field, which received 66% less water and 37% less N fertilizer than the conventional field; and (iv) a center pivot-irrigated alfalfa (Medicago sativa L.) field. Dating (3H/3He) indicated that the uppermost ground water was <1 to 2 yr old and that the aquifer water was stratified with the deepest water approximately 20 yr old. Recharge during the wet growing season in 1993 reduced the average NO3-N concentration in the top 3 m 20 mg L(-1), effectively diluting and replacing the NO3-contaminated water. Nitrate concentrations in the shallow zone of the aquifer increased with depth to water. Beneath the conventional and surge-irrigated fields, shallow ground water concentrations returned to the initial 30 mg NO3-N L(-1) level by fall 1995; however, beneath the center pivot-irrigated corn field, concentrations remained at approximately 13 mg NO3-N L(-1) until fall 1996. A combination of sprinkler irrigation and N fertigation significantly reduced N leaching with only minor reductions (6%) in crop yield. PMID:11476495

  10. Nitrate Degradation in the Aquifer of an Agricultural Catchment - An Integrative Modelling Approach

    NASA Astrophysics Data System (ADS)

    Kolbe, T.

    2015-12-01

    Agricultural activity has increased nitrate concentration in aquifers worldwide, which represents one of the major environmental challenges of our generation. Nitrate is highly mobile in groundwater and if transported to denitrifying environments (i.e. anaerobic areas with the presence of bioavailable organic carbon (basis for heterotrophic denitrification) or pyrite (basis for autotrophic denitrification)) degraded to nitrogenous gas. These areas are often small, but account for a high percentage of nitrate removal. Consequential groundwater flow, a nitrate supplier to these hot spots, influence significantly the fate of nitrate. A hydro-geochemical modeling approach is used to demonstrate the relation between nitrate inputs and denitrifying services provided by catchment structure and flow dynamics. A developed three-dimensional numerical groundwater flow model is capable to map groundwater flow and visualize preferential nitrate flow paths in a 35 km2 agricultural catchment, western France. Environmental proxies for microbial processes (natural isotopic abundance of nitrogen and oxygen) are used to identify denitrification processes in the aquifer. These information are combined with the flow paths obtained by the groundwater model in a post-processing step. An overall understanding of groundwater flow patterns and therefore nitrate input to denitrifying environments yield to better management decisions and predictions for nitrate attenuation.

  11. Relation of nitrate concentrations in water to agricultural land use and soil type in Dakota County, Minnesota, 1990

    USGS Publications Warehouse

    Almendinger, James Edward

    1991-01-01

    Nitrate is commonly found in ground water in agricultural areas throughout the Midwest. The emphasis of this report is to relate differences in nitrate concentrations in ground water to agricultural land use and soil type. In addition, nitrate concentrations in streams, shallow ground water near the water table, and deeper ground water from 10 to 30 feet below the water table are tabulated for selected sites in Dakota County.

  12. The influence of nitrate leaching through unsaturated soil on groundwater pollution in an agricultural area of the Basque country: a case study.

    PubMed

    Pérez, José Miguel Sánchez; Antiguedad, Iñaki; Arrate, Iñaki; García-Linares, Cristina; Morell, Ignacio

    2003-12-30

    The average nitrate concentration in the groundwater of the Vitoria-Gasteiz (Basque Country) quaternary aquifer rose from 50 mg NO3-/l during 1986 to over 200 mg/l in 1995, which represents an increase of some 20 mg NO3-/l per year. From 1995 to 2002, the nitrate concentration of the groundwater slightly decreased. Nitrate groundwater pollution during the period 1986-1993 was the result of the abusive use of fertilizers and of the modification in the recharge patterns of the aquifer from surface water sources. From 1993 onwards, apart from a possible rationalization in fertilizer use, the change in the origin of water for irrigation and wetland restoration (water is taken now from artificial pools outside the quaternary aquifer) must be explained in order to account for the observed decrease in nitrate concentration in the groundwater. The water of the aquifer and of the unsaturated zone were studied in two experimental plots (one of them cultivated and the other uncultivated) for 18 months (January 1993-June 1994), during the period of maximum contamination, to evaluate the effect of fertilizers on soil water and on the water in the saturated zone. The soil water was sampled using soil lysimeters at various depths. The volumetric water content of the soil was measured at the same depths using time domain reflectrometry (TDR) probes. Samples of groundwater were taken from a network of wells on the aquifer scale, two located close to the two experimental plots. The temporal evolution of nitrate concentrations in soil solutions depends on the addition of fertilizers and on soil nitrate leaching by rain. During episodes of intense rain (>50 mm in a day), the groundwater deposits are recharged with water coming from the leaching of interstitial soil solutions, causing an increase in the groundwater nitrate concentrations. The mass of nitrate leached from the cultivated zone is five times higher than that of the nitrate leached from the uncultivated zone (1147 kg NO3

  13. Application of municipal sludge (biosolids) for agricultural purposes and groundwater nitrate concentrations

    SciTech Connect

    Welby, C.W. . Dept. of Marine, Earth and Atmospheric Sciences)

    1993-03-01

    One of the more popular means of handling sewage sludge from municipalities is its application to agricultural lands. A variety of crops are grown with the expectation that plants will utilize the nitrogen. However, a complex scenario allows some of the nitrate to move below root depth and eventually to the water table at depths of up to 30 ft. The City of Raleigh, NC injects sewage sludge ( residuals'', biosolids'') into soils derived largely from the Rolesville Granite in an area of typical rolling Piedmont topography. A 1975 background study of part of the site demonstrated differences in groundwater quality between areas farmed over a period of years and areas dominated by second-growth pine and harwood forests. Groundwater quality data collected semiannually between 1982 and 1988 show gradual buildup of nitrate in some fields; in others groundwater quality apparently remains unaffected by nitrate from the sludge. Monitoring well placement may play a role in these differences. Minimum time from the sludge application to an increase in groundwater nitrate is from 9 to 12 months. An ongoing study of a 12-acre field which lay fallow for a number of years prior to sludge application in 1990 demonstrates that some nitrate does move downward fairly rapidly, its movement being recorded in both the saprolite and groundwater. Comparison of nitrate content of groundwater from monitoring wells at a nearby dairy farm shows that normal agricultural practices may also increase the nitrate content of the shallow groundwater.

  14. Groundwater head controls nitrate export from an agricultural lowland catchment

    NASA Astrophysics Data System (ADS)

    Musolff, Andreas; Schmidt, Christian; Rode, Michael; Lischeid, Gunnar; Weise, Stephan M.; Fleckenstein, Jan H.

    2016-10-01

    Solute concentration variability is of fundamental importance for the chemical and ecological state of streams. It is often closely related to discharge variability and can be characterized in terms of a solute export regime. Previous studies, especially in lowland catchments, report that nitrate is often exported with an accretion pattern of increasing concentrations with increasing discharge. Several modeling approaches exist to predict the export regime of solutes from the spatial relationship of discharge generating zones with solute availability in the catchment. For a small agriculturally managed lowland catchment in central Germany, we show that this relationship is controlled by the depth to groundwater table and its temporal dynamics. Principal component analysis of groundwater level time series from wells distributed throughout the catchment allowed derivation of a representative groundwater level time series that explained most of the discharge variability. Groundwater sampling revealed consistently decreasing nitrate concentrations with an increasing thickness of the unsaturated zone. The relationships of depth to groundwater table to discharge and to nitrate concentration were parameterized and integrated to successfully model catchment discharge and nitrate export on the basis of groundwater level variations alone. This study shows that intensive and uniform agricultural land use likely results in a clear and consistent concentration-depth relationship of nitrate, which can be utilized in simple approaches to predict stream nitrate export dynamics at the catchment scale.

  15. Non-agricultural sources of groundwater nitrate: a review and case study.

    PubMed

    Wakida, Fernando T; Lerner, David N

    2005-01-01

    Nitrate is often seen as an agricultural pollutant of groundwater and so is expected to be at higher concentrations in the groundwaters surrounding a city than in those beneath it. However the difference between rural and urban nitrate concentrations is often small, due to the non-agricultural sources of nitrogen that are concentrated in cities. This paper illustrates the source and significance of non-agricultural nitrogen for groundwater and presents a case study of nitrate loading in the city of Nottingham. Major sources of nitrogen in urban aquifers are related to wastewater disposal (on-site systems and leaky sewers), solid waste disposal (landfills and waste tips). The major sources of nitrogen in the Nottingham area are mains leakage and contaminated land with approximately 38% each of a total load of 21 kg N ha(-1) year(-1).

  16. Agriculture causes nitrate fertilization of remote alpine lakes.

    PubMed

    Hundey, E J; Russell, S D; Longstaffe, F J; Moser, K A

    2016-01-01

    Humans have altered Earth's nitrogen cycle so dramatically that reactive nitrogen (Nr) has doubled. This has increased Nr in aquatic ecosystems, which can lead to reduced water quality and ecosystem health. Apportioning sources of Nr to specific ecosystems, however, continues to be challenging, despite this knowledge being critical for mitigation and protection of water resources. Here we use Δ(17)O, δ(18)O and δ(15)N from Uinta Mountain (Utah, USA) snow, inflow and lake nitrate in combination with a Bayesian-based stable isotope mixing model, to show that at least 70% of nitrates in aquatic systems are anthropogenic and arrive via the atmosphere. Moreover, agricultural activities, specifically nitrate- and ammonium-based fertilizer use, are contributing most (∼60%) Nr, and data from other North American alpine lakes suggest this is a widespread phenomenon. Our findings offer a pathway towards more effective mitigation, but point to challenges in balancing food production with protection of important water resources. PMID:26853267

  17. Agriculture causes nitrate fertilization of remote alpine lakes

    NASA Astrophysics Data System (ADS)

    Hundey, E. J.; Russell, S. D.; Longstaffe, F. J.; Moser, K. A.

    2016-02-01

    Humans have altered Earth's nitrogen cycle so dramatically that reactive nitrogen (Nr) has doubled. This has increased Nr in aquatic ecosystems, which can lead to reduced water quality and ecosystem health. Apportioning sources of Nr to specific ecosystems, however, continues to be challenging, despite this knowledge being critical for mitigation and protection of water resources. Here we use Δ17O, δ18O and δ15N from Uinta Mountain (Utah, USA) snow, inflow and lake nitrate in combination with a Bayesian-based stable isotope mixing model, to show that at least 70% of nitrates in aquatic systems are anthropogenic and arrive via the atmosphere. Moreover, agricultural activities, specifically nitrate- and ammonium-based fertilizer use, are contributing most (~60%) Nr, and data from other North American alpine lakes suggest this is a widespread phenomenon. Our findings offer a pathway towards more effective mitigation, but point to challenges in balancing food production with protection of important water resources.

  18. Agriculture causes nitrate fertilization of remote alpine lakes

    PubMed Central

    Hundey, E. J.; Russell, S. D.; Longstaffe, F. J.; Moser, K. A.

    2016-01-01

    Humans have altered Earth's nitrogen cycle so dramatically that reactive nitrogen (Nr) has doubled. This has increased Nr in aquatic ecosystems, which can lead to reduced water quality and ecosystem health. Apportioning sources of Nr to specific ecosystems, however, continues to be challenging, despite this knowledge being critical for mitigation and protection of water resources. Here we use Δ17O, δ18O and δ15N from Uinta Mountain (Utah, USA) snow, inflow and lake nitrate in combination with a Bayesian-based stable isotope mixing model, to show that at least 70% of nitrates in aquatic systems are anthropogenic and arrive via the atmosphere. Moreover, agricultural activities, specifically nitrate- and ammonium-based fertilizer use, are contributing most (∼60%) Nr, and data from other North American alpine lakes suggest this is a widespread phenomenon. Our findings offer a pathway towards more effective mitigation, but point to challenges in balancing food production with protection of important water resources. PMID:26853267

  19. Evaluating nitrate sources in nested agricultural sub-basins using nitrate stable isotopes

    NASA Astrophysics Data System (ADS)

    Chang, C. C.; Frey, J. W.; Kim, M.; Kendall, C.

    2005-05-01

    Nutrient enrichment is the second leading cause of drinking water contamination in the United States. To provide environmental managers with nutrient source and transport information, the U.S. Geological Survey' s National Water-Quality Assessment (NAWQA) Program conducted a multi-component study in Sugar Creek Basin, Indiana, in which major nutrients, cations, anions, and pesticides were analyzed. Land use at Sugar Creek (246 square km basin) is dominated by row crop agriculture, primarily corn and soybeans. The soils are largely heavy clay, glacial till in origin, and require tile drains to move excess water and make the land farmable. As one component of the study, stable isotopes of nitrate (N-15 and O-18) were used to examine nitrate sources and transport, and possible transformations of nitrate. Water samples were collected in 2003 and 2004 from major environmental compartments involved with the movement of nutrients into the creek, (precipitation, tile drain, and overland flow). Samples were also collected from Leary-Weber Ditch, a 6.2 square km basin is nested within Sugar Creek. Collection times bracketing four distinct periods of the agricultural cycle: pre-application of fertilizer, post-application of fertilizer, growing season, and post-harvest periods. Nutrient samples (nitrate, phosphate, ammonia) were also collected several times between storm events during baseflow conditions. Preliminary nutrient and pesticide data indicate that tile drains are the primary pathway into streams. Little interaction occurs between the ground water and surface water interface. Nitrate stable isotopes will enable us to determine the relative contribution of nitrate sources feeding in from the tile drains, into Leary-Weber Ditch and Sugar Creek.

  20. Modeling nitrate contamination of groundwater in agricultural watersheds

    NASA Astrophysics Data System (ADS)

    Almasri, Mohammad N.; Kaluarachchi, Jagath J.

    2007-09-01

    SummaryThis paper presents and implements a framework for modeling the impact of land use practices and protection alternatives on nitrate pollution of groundwater in agricultural watersheds. The framework utilizes the national land cover database (NLCD) of the United State Geological Survey (USGS) grid and a geographic information system (GIS) to account for the spatial distribution of on-ground nitrogen sources and corresponding loadings. The framework employs a soil nitrogen dynamic model to estimate nitrate leaching to groundwater. These estimates were used in developing a groundwater nitrate fate and transport model. The framework considers both point and non-point sources of nitrogen across different land use classes. The methodology was applied for the Sumas-Blaine aquifer of Washington State, US, where heavy dairy industry and berry plantations are concentrated. Simulations were carried out using the developed framework to evaluate the overall impacts of current land use practices and the efficiency of proposed protection alternatives on nitrate pollution in the aquifer.

  1. Nation-wide trend in nitrate concentration of agricultural groundwater of Korea

    NASA Astrophysics Data System (ADS)

    Lim, J.; Kim, J.; Lee, S.; Lee, K.

    2013-12-01

    Nation-wide monitoring of groundwater in agricultural areas of Korea showed that about 27% of the total 3000 wells violate the groundwater standard of their relevant usage. Concerning nitrate concentration, 22% of the total wells are shown to exceed the relevant standard. The agricultural use of nitrates in organic and chemical fertilizers has been known as a major source of groundwater pollution. In the aim of protecting groundwater quality across the nation, this study analyzed the land use relationship with the nitrate concentration and the trend in water quality at each groundwater monitoring well. As the data had been collected from all over the nation, the characteristics of the data were needed to be scrutinized. With the analysis of variance (ANOVA), the data is tested for whether they are from the same population or not. Then, for the data from the same population, the Tobit regression model of multivariate analysis is applied in finding the relationship between the various types of land use and the nitrate concentration. For trend analysis of the water quality, nonparametric method of the Mann-Kendall test is applied. Both the seasonal characteristic and the total trend exclusive of the seasonal variation are analyzed. This study is expected to provide a sound basis in implementing effective actions for water quality protection in agricultural areas.

  2. Agricultural Colleges in Rural Areas

    ERIC Educational Resources Information Center

    Yi, Tung

    1975-01-01

    This article describes the educational program developed by one agricultural college in a rural area of China to carry out the revolution in education. Educational theory and practice are linked by involving students in the running of three forms.

  3. Building factorial regression models to explain and predict nitrate concentrations in groundwater under agricultural land

    NASA Astrophysics Data System (ADS)

    Stigter, T. Y.; Ribeiro, L.; Dill, A. M. M. Carvalho

    2008-07-01

    SummaryFactorial regression models, based on correspondence analysis, are built to explain the high nitrate concentrations in groundwater beneath an agricultural area in the south of Portugal, exceeding 300 mg/l, as a function of chemical variables, electrical conductivity (EC), land use and hydrogeological setting. Two important advantages of the proposed methodology are that qualitative parameters can be involved in the regression analysis and that multicollinearity is avoided. Regression is performed on eigenvectors extracted from the data similarity matrix, the first of which clearly reveals the impact of agricultural practices and hydrogeological setting on the groundwater chemistry of the study area. Significant correlation exists between response variable NO3- and explanatory variables Ca 2+, Cl -, SO42-, depth to water, aquifer media and land use. Substituting Cl - by the EC results in the most accurate regression model for nitrate, when disregarding the four largest outliers (model A). When built solely on land use and hydrogeological setting, the regression model (model B) is less accurate but more interesting from a practical viewpoint, as it is based on easily obtainable data and can be used to predict nitrate concentrations in groundwater in other areas with similar conditions. This is particularly useful for conservative contaminants, where risk and vulnerability assessment methods, based on assumed rather than established correlations, generally produce erroneous results. Another purpose of the models can be to predict the future evolution of nitrate concentrations under influence of changes in land use or fertilization practices, which occur in compliance with policies such as the Nitrates Directive. Model B predicts a 40% decrease in nitrate concentrations in groundwater of the study area, when horticulture is replaced by other land use with much lower fertilization and irrigation rates.

  4. A multi-tracer approach to assess fingerprints of nitrate in an aquifer under agriculturally used land

    NASA Astrophysics Data System (ADS)

    Pasten-Zapata, Ernesto; Ledesma-Ruiz, Rogelio; Ramirez, Aldo; Harter, Thomas; Mahlknecht, Jürgen

    2014-05-01

    To effectively manage groundwater quality it is essential to understand sources of contamination and underground processes. The objective of the study was to identify sources and fate of nitrate pollution occurring in an aquifer underneath a sub-humid to humid region in NE Mexico which provides 10% of national citrus production. Nitrate isotopes and halide ratios were applied to understand nitrate sources and transformations in relation to land use/land cover. It was found that the study area is subject to diverse nitrate sources including organic waste and wastewater, synthetic fertilizers and soil processes. Animal manure and sewage from septic tanks were the causes of groundwater nitrate pollution within orchards and vegetable agriculture. Dairy activities within a radius of 1,000m from a sampling point increased nitrate pollution. Leachates from septic tanks incited nitrate pollution in residential areas. Soil nitrogen and animal waste were the sources of nitrate in groundwater under shrubland and grassland. Partial denitrification processes were evidenced. The denitrification process helped to attenuate nitrate concentration in the agricultural lands and grassland particularly during summer months.

  5. Assessment and management of long-term nitrate pollution of ground water in agriculture-dominated watersheds

    NASA Astrophysics Data System (ADS)

    Almasri, Mohammad N.; Kaluarachchi, Jagath J.

    2004-08-01

    The objectives of this paper are to document and evaluate regional long-term trends and occurrences of nitrate in the ground water of agricultural watersheds. In Whatcom County, Washington, elevated nitrate concentrations in ground water are of great concern. Whatcom County is recognized by heavy agricultural activities, especially an intensive dairy farm industry. Historical nitrate concentration data from 1990 to 2000 were compiled from different agencies and assembled into a single composite database. A geographic information system was used to assess the spatial and temporal variability of nitrogen data. The analysis was conducted for the whole area as well as for individual watersheds and for different land use classes. In addition, nitrate concentration variability with descriptive parameters such as sampling depth, ground water recharge, dissolved oxygen, and on-ground nitrogen loadings was also investigated. The analysis showed that the areas with nitrate concentrations above the maximum contaminant level are areas characterized by heavy agricultural activities. The shallow surficial aquifers of the study area were found to contain high mean nitrate concentrations when compared to non-surficial aquifers. The analysis showed that high nitrate presence corresponds to areas with both high ground water recharge and high on-ground nitrogen loadings. In addition, the nitrate concentration decreased with increasing sampling depth. In general, the trend of long-term nitrate concentration remained elevated in shallow aquifers due to the persistent on-ground nitrogen loadings produced by agriculture-related land use practices. Finally, the watersheds were prioritized for management intervention, alternatives, and data monitoring based on a number of decision variables.

  6. Hydrogeologic controls on nitrate transport in a small agricultural catchment, Iowa

    USGS Publications Warehouse

    Schilling, K.E.; Tomer, M.D.; Zhang, Y.-K.; Weisbrod, T.; Jacobson, P.; Cambardella, C.A.

    2007-01-01

    Effects of subsurface deposits on nitrate loss in stream riparian zones are recognized, but little attention has been focused on similar processes occurring in upland agricultural settings. In this paper, we evaluated hydrogeologic controls on nitrate transport processes occurring in a small 7.6 ha Iowa catchment. Subsurface deposits in the catchment consisted of upland areas of loess overlying weathered pre-Illinoian till, drained by two ephemeral drainageways that consisted of Holocene-age silty and organic rich alluvium. Water tables in upland areas fluctuated more than 4 m per year compared to less than 0.3 m in the drainageway. Water quality patterns showed a distinct spatial pattern, with groundwater in the drainageways having lower nitrate concentrations (10 mg L-1) as wells as lower pH, dissolved oxygen and redox, and higher ammonium and dissolved organic carbon levels. Several lines of evidence suggested that conditions are conducive for denitrification of groundwater flowing from uplands through the drainageways. Field-measured nitrate decay rates in the drainageways (???0.02 day-1) were consistent with other laboratory studies and regional patterns. Results from MODFLOW and MT3DMS simulations indicated that soils in the ephemeral drainageways could process all upland groundwater nitrate flowing through them. However, model-simulated tile drainage increased both water flux and nitrate loss from the upland catchment. Study results suggest that ephemeral drainageways can provide a natural nitrate treatment system in our upland glaciated catchments, offering management opportunities to reduce nitrate delivery to streams. Copyright 2007 by the American Geophysical Union.

  7. Evaluation of nitrate removal in buffer zone supply by water from agricultural drained catchment

    NASA Astrophysics Data System (ADS)

    Fesneau, Corinne; Tournebize, Julien; Chaumont, Cedric; Guenne, Angeline

    2010-05-01

    The European Directive 2000/60/CE states objectives of a good ecological and chemical status from water body until 2015. The Cemagref project focuses on the constructed wetlands (CW) which can be used as buffer zones to lower the impact of agricultural practices on hydrosystems and decrease or even stop the transfer of contaminants via the surface waters. The experiments are carried out on a drained area where the runoff is limited and waters from the soil profile are concentrated at the drain pipes outlet. The constructed wetland studied is located at Aulnoy (77) at 70 km north-east of Paris, within the Orgeval catchment (France). Our aim is to assess the efficiency of constructed wetlands on the removal of agricultural nitrates. We are also interested in the hydrological balance of CW and agricultural catchment. The buffer zone is connected to a drained agricultural catchment of 35 hectares. The crops in the agricultural plots mainly consist in cereals (corn, maize), vegetables (horse bean, pea), sugar beet and rape. Nitrogen fertilizers are applied following normal agricultural practices. The site is monitored since 2005 for discharge and nitrate concentration in order to infer water and nitrate budgets. The buffer zone includes a pond (860m2) and a reservoir (3305 m2). The storage volume is estimated to 8000m3 which corresponds to about 10% of drainage runoff. Our study reveals potential nitrate removal because a decrease of nitrate average contents has been documented between inlet and outlet CW over a measurement period of 4 years. Average values of 57 mg/l, 40 mg/l and 27 mg/l are respectively measured at the main drain, in the pond mean and in the reservoir; that is a reduction close to 50% of nitrate fluxes. The semi-potential denitrification experiments confirm the denitrification capacity of buffer zone sediments. This constructed wetland allows the treatment of waters from agricultural drainage and provides results in line with the expectations of "good

  8. Metolachlor metabolite (MESA) reveals agricultural nitrate-N fate and transport in Choptank River watershed

    USGS Publications Warehouse

    McCarty, Gregory W.; Hapeman, Cathleen J.; Rice, Clifford P.; Hively, W. Dean; McConnell, Laura L.; Sadeghi, Ali M.; Lang, Megan W.; Whitall, David R.; Bialek, Krystyna; Downey, Peter

    2014-01-01

    Over 50% of streams in the Chesapeake Bay watershed have been rated as poor or very poor based on the index of biological integrity. The Choptank River estuary, a Bay tributary on the eastern shore, is one such waterway, where corn and soybean production in upland areas of the watershed contribute significant loads of nutrients and sediment to streams. We adopted a novel approach utilizing the relationship between the concentration of nitrate-N and the stable, water-soluble herbicide degradation product MESA {2-[2-ethyl-N-(1-methoxypropan-2-yl)-6-methylanilino]-2-oxoethanesulfonic acid} to distinguish between dilution and denitrification effects on the stream concentration of nitrate-N in agricultural subwatersheds. The ratio of mean nitrate-N concentration/(mean MESA concentration * 1000) for 15 subwatersheds was examined as a function of percent cropland on hydric soil. This inverse relationship (R2 = 0.65, p 2 ≤ 0.99) for all eight sampling dates except one where R2 = 0.90. This very strong correlation indicates that nitrate-N was conserved in much of the Choptank River estuary, that dilution alone is responsible for the changes in nitrate-N and MESA concentrations, and more importantly nitrate-N loads are not reduced in the estuary prior to entering the Chesapeake Bay. Thus, a critical need exists to minimize nutrient export from agricultural production fields and to identify specific conservation practices to address the hydrologic conditions within each subwatershed. In well drained areas, removal of residual N within the cropland is most critical, and practices such as cover crops which sequester the residual N should be strongly encouraged. In poorly drained areas where denitrification can occur, wetland restoration and controlled drained structures that minimize ditch flow should be used to maximize denitrification.

  9. Metolachlor metabolite (MESA) reveals agricultural nitrate-N fate and transport in Choptank River watershed.

    PubMed

    McCarty, Gregory W; Hapeman, Cathleen J; Rice, Clifford P; Hively, W Dean; McConnell, Laura L; Sadeghi, Ali M; Lang, Megan W; Whitall, David R; Bialek, Krystyna; Downey, Peter

    2014-03-01

    Over 50% of streams in the Chesapeake Bay watershed have been rated as poor or very poor based on the index of biological integrity. The Choptank River estuary, a Bay tributary on the eastern shore, is one such waterway, where corn and soybean production in upland areas of the watershed contribute significant loads of nutrients and sediment to streams. We adopted a novel approach utilizing the relationship between the concentration of nitrate-N and the stable, water-soluble herbicide degradation product MESA {2-[2-ethyl-N-(1-methoxypropan-2-yl)-6-methylanilino]-2-oxoethanesulfonic acid} to distinguish between dilution and denitrification effects on the stream concentration of nitrate-N in agricultural subwatersheds. The ratio of mean nitrate-N concentration/(mean MESA concentration * 1000) for 15 subwatersheds was examined as a function of percent cropland on hydric soil. This inverse relationship (R(2)=0.65, p<0.001) takes into consideration not only dilution and denitrification of nitrate-N, but also the stream sampling bias of the croplands caused by extensive drainage ditch networks. MESA was also used to track nitrate-N concentrations within the estuary of the Choptank River. The relationship between nitrate-N and MESA concentrations in samples collected over three years was linear (0.95 ≤ R(2) ≤ 0.99) for all eight sampling dates except one where R(2)=0.90. This very strong correlation indicates that nitrate-N was conserved in much of the Choptank River estuary, that dilution alone is responsible for the changes in nitrate-N and MESA concentrations, and more importantly nitrate-N loads are not reduced in the estuary prior to entering the Chesapeake Bay. Thus, a critical need exists to minimize nutrient export from agricultural production fields and to identify specific conservation practices to address the hydrologic conditions within each subwatershed. In well drained areas, removal of residual N within the cropland is most critical, and practices such

  10. 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

  11. Agriculture and groundwater nitrate contamination in the Seine basin. The STICS-MODCOU modelling chain.

    PubMed

    Ledoux, E; Gomez, E; Monget, J M; Viavattene, C; Viennot, P; Ducharne, A; Benoit, M; Mignolet, C; Schott, C; Mary, B

    2007-04-01

    A software package is presented here to predict the fate of nitrogen fertilizers and the transport of nitrate from the rooting zone of agricultural areas to surface water and groundwater in the Seine basin, taking into account the long residence times of water and nitrate in the unsaturated and aquifer systems. Information on pedological characteristics, land use and farming practices is used to determine the spatial units to be considered. These data are converted into input data for the crop model STICS which simulates the water and nitrogen balances in the soil-plant system with a daily time-step. A spatial application of STICS has been derived at the catchment scale which computes the water and nitrate fluxes at the bottom of the rooting zone. These fluxes are integrated into a surface and groundwater coupled model MODCOU which calculates the daily water balance in the hydrological system, the flow in the rivers and the piezometric variations in the aquifers, using standard climatic data (rainfall, PET). The transport of nitrate and the evolution of nitrate contamination in groundwater and to rivers is computed by the model NEWSAM. This modelling chain is a valuable tool to predict the evolution of crop productivity and nitrate contamination according to various scenarios modifying farming practices and/or climatic changes. Data for the period 1970-2000 are used to simulate the past evolution of nitrogen contamination. The method has been validated using available data bases of nitrate concentrations in the three main aquifers of the Paris basin (Oligocene, Eocene and chalk). The approach has then been used to predict the future evolution of nitrogen contamination up to 2015. A statistical approach allowed estimating the probability of transgression of different concentration thresholds in various areas in the basin. The model is also used to evaluate the cost of the damage resulting of the treatment of drinking water at the scale of a groundwater management

  12. Sources of nitrate exposure in residents of rural areas in Quebec, Canada.

    PubMed

    Levallois, P; Ayotte, P; Louchini, R; Desrosiers, T; Baribeau, H; Phaneuf, D; Gingras, S; Dumas, P; Zee, J; Poirier, G

    2000-01-01

    Nitrate exposure was investigated in a group of 187 people using well water and living in four areas of rural Quebec (Canada) with intensive agricultural activities. Nitrate intake was evaluated using a 24-h dietary recall and a food frequency questionnaire, in conjunction with a validated food database and measurements of nitrate concentrations in private wells. The total internal dose was estimated by means of the 24-h urinary nitrate excretion, while taking into account risk factors for endogenous nitrate formation. Mean (geometric) 24-h urinary nitrate excretion was 16.9 mg N for the 100 people with low groundwater contamination (mean nitrate concentration=0.18 mg N/l) and 23.3 mg N in the 87 individuals with moderate groundwater contamination (mean nitrate concentration=7.1 mg N/l). A multivariate analysis revealed that dietary nitrate intake during the last 24 h was the principal source of exposure, followed by water intake during the last 24 h. The Quetelet index was also a significant predictor of urinary excretion. The total predictive model explained only 29% of the variability in urinary nitrate excretion (R2=0.286). Neither the inflammatory status as indicated by elevated C reactive protein, the presence of Helicobacter pylori antibodies nor the occurrence of diarrhea during the last 24 h prior to urine collection were associated with urinary nitrate excretion. In conclusion, food and to a lesser extent water contribute to nitrate exposure in this rural setting with moderate water contamination. Better predictors of endogenous nitrate production are needed to improve our ability to model nitrate body burden and estimate associated health risks.

  13. Nitrate in shallow groundwater in typical agricultural and forest ecosystems in China, 2004-2010.

    PubMed

    Zhang, Xinyu; Xu, Zhiwei; Sun, Xiaomin; Dong, Wenyi; Ballantine, Deborah

    2013-05-01

    The nitrate-nitrogen (NO3(-)-N) concentrations from shallow groundwater wells situated in 29 of the Chinese Ecosystem Research Network field stations, representing typical agro- and forest ecosystems, were assessed using monitoring data collected between 2004 and 2010. Results from this assessment permit a national scale assessment of nitrate concentrations in shallow groundwater, and allow linkages between nitrate concentrations in groundwater and broad land use categories to be made. Results indicated that most of the NO3(-)-N concentrations in groundwater from the agro- and forest ecosystems were below the Class 3 drinking water standard stated in the Chinese National Standard: Quality Standard for Ground Water (< or = 20 mg/L). Over the study period, the average NO3(-)-N concentrations were significantly higher in agro-ecosystems (4.1 +/- 0.33 mg/L) than in forest ecosystems (0.5 +/- 0.04 mg/L). NO3(-)-N concentrations were relatively higher (> 10 mg N /L) in 10 of the 43 wells sampled in the agricultural ecosystems. These elevated concentrations occurred mainly in the Ansai, Yucheng, Linze, Fukang, Akesu, and Cele field sites, which were located in arid and semi-arid areas where irrigation rates are high. We suggest that improvements in N fertilizer application and irrigation management practices in the arid and semi-arid agricultural ecosystems of China are the key to managing groundwater nitrate concentrations. PMID:24218832

  14. Nitrate in shallow groundwater in typical agricultural and forest ecosystems in China, 2004-2010.

    PubMed

    Zhang, Xinyu; Xu, Zhiwei; Sun, Xiaomin; Dong, Wenyi; Ballantine, Deborah

    2013-05-01

    The nitrate-nitrogen (NO3(-)-N) concentrations from shallow groundwater wells situated in 29 of the Chinese Ecosystem Research Network field stations, representing typical agro- and forest ecosystems, were assessed using monitoring data collected between 2004 and 2010. Results from this assessment permit a national scale assessment of nitrate concentrations in shallow groundwater, and allow linkages between nitrate concentrations in groundwater and broad land use categories to be made. Results indicated that most of the NO3(-)-N concentrations in groundwater from the agro- and forest ecosystems were below the Class 3 drinking water standard stated in the Chinese National Standard: Quality Standard for Ground Water (< or = 20 mg/L). Over the study period, the average NO3(-)-N concentrations were significantly higher in agro-ecosystems (4.1 +/- 0.33 mg/L) than in forest ecosystems (0.5 +/- 0.04 mg/L). NO3(-)-N concentrations were relatively higher (> 10 mg N /L) in 10 of the 43 wells sampled in the agricultural ecosystems. These elevated concentrations occurred mainly in the Ansai, Yucheng, Linze, Fukang, Akesu, and Cele field sites, which were located in arid and semi-arid areas where irrigation rates are high. We suggest that improvements in N fertilizer application and irrigation management practices in the arid and semi-arid agricultural ecosystems of China are the key to managing groundwater nitrate concentrations.

  15. Nitrate pollution in groundwater in some rural areas of Nalgonda district, Andhra Pradesh, India.

    PubMed

    Brindha, K; Rajesh, R; Murugan, R; Elango, L

    2012-01-01

    Intake of water with high concentration of nitrate is a major problem in many countries as it affects health of humans. The present study was carried out with the objective of determining the causes for higher nitrate concentration in groundwater in parts of Nalgonda district, Andhra Pradesh, India. The study area is located at a distance of about 135 km towards ESE direction from Hyderabad. Nitrate concentration in groundwater of this area was analysed by collecting groundwater samples from 46 representative wells. Samples were collected once in two months from March 2008 to January 2009. The nitrate concentration was analysed in the laboratory using Metrohm 861 advanced compact ion chromatograph using appropriate standards. The highest concentration recorded during the sampling period was 879.65 mg/L and the lowest concentration was below detection limit. Taking into consideration 45 mg/L of nitrate as the maximum permissible limit for drinking water set by BIS, it was found that 13.78% of the groundwater samples collected from this study area possessed nitrate concentration beyond the limit. Overall, wells present in agricultural fields had nitrate levels within permissible limits when compared to those groundwater samples from wells present in settlements which are used for domestic purpose. This indicates that the high nitrate concentration in groundwater of this area is due to poor sanitation facilities and leaching from indiscriminate dumping of animal waste.

  16. Seasonal Variation in Hydrology Driving Shifts in Sources of Nitrate in an Agricultural Dominant Semi-arid Watershed

    NASA Astrophysics Data System (ADS)

    Moon Nielsen, L. G.; Orr, C. H.

    2010-12-01

    In the South Fork Palouse River in the semi-arid region of Eastern Washington State, surface water hydrology is driven by seasonal variation in precipitation, with peak surface water flow and highest Nitrate values observed from January to April, and lowest surface flows and corresponding lower Nitrate concentrations observed from June to August. Land-use in the watershed is predominantly non-irrigated cropland (82%) fertilized by synthetic fertilizer, with an additional 8% of land in urban areas. Due to the prevalence of anthropogenically influenced land in the watershed, Nitrate concentrations measured in streams here are chronically elevated above natural levels. Typically in an area that is dominated by agriculture, the source of Nitrate in surface waters draining agricultural land would be predicted to be synthetic fertilizer. However it is important to consider the impacts seasonal hydrological conditions can have upon Nitrate sources and flow paths. We investigated how Nitrate sources in Palouse streams and rivers changed seasonally to address the hypothesis that seasonal variation in precipitation shifts the dominant sources of Nitrate in surface waters. We based our determination of nitrogen source on the results from dual stable isotope analysis of Nitrate using the denitrifier method. Sampling was done at 7 locations of increasing catchment area along the South Fork Palouse River and tributary streams. Sampling site catchment area varied one order of magnitude from 70.9 to 717.4 km2. Surface waters at yearly low flow during the summer season indicated δ15N-Nitrate and δ18O-Nitrate ranging within generally accepted values to indicate Nitrate derived from animal and human waste. These can be attributed to waste water discharge from the urban areas in the watershed. Yearly hydrologic data suggests that during the winter season, increased precipitation causes a shift in δ15N-Nitrate and δ18O-Nitrate to values typically observed in sources derived from

  17. Comparison of policies for controlling groundwater nitrate pollution from agriculture in the Eastern Mancha aquifer (Spain).

    NASA Astrophysics Data System (ADS)

    Peña-Haro, S.; Llopis-Albert, C.; Pulido-Velazquez, M.; Stalder, A.; Garcia-Prats, A.; Henriquez-Dole, L.

    2012-04-01

    Groundwater nitrate pollution from agriculture has given rise to different legal frameworks. The European Water Framework Directive (WFD) is the most recent one. This work aims to help in the definition of the most cost-efficient policy to control non-point groundwater to attain the objectives established in the WFD. In this study we performed a cost-effectiveness analysis of different policies for controlling groundwater nitrate pollution from agriculture. The policies considered were taxes on nitrogen fertilizers, water price, taxes on emissions and fertilizer standards. We used a hydro-economic model, where we maximized the farmer's benefits. The benefits were calculated as sum of crop revenue minus variable and fixed cost per hectare minus the damage costs from nitrogen leaching. In the cost-effectiveness analysis we considered the costs as the reduction on benefits due to the application of a policy and the effectiveness the reduction on nitrate leaching. The methodology was applied to Eastern Mancha aquifer in Spain. The aquifer is part of the Júcar River Basin, which was declared as EU Pilot Basin in 2002 for the implementation of the WFD. Over the past 30 years the area has undertaken a significant socioeconomic development, mainly due to the intensive groundwater use for irrigated crops, which has provoked a steady decline of groundwater levels and a reduction of groundwater discharged into the Júcar River, as well as nitrate concentrations higher than those allowed by the WFD at certain locations (above 100 mg/l.). Crop revenue was calculated using production functions and the amount of nitrate leached was estimated by calibrated leaching functions. These functions were obtained by using an agronomic model (a GIS version of EPIC, GEPIC), and they depend on the water and the fertilizer use. The Eastern Mancha System was divided into zones of homogeneous crop production and nitrate leaching properties. Given the different soil types and climatic

  18. Optimizing Sampling Strategies for Riverine Nitrate Using High-Frequency Data in Agricultural Watersheds.

    PubMed

    Reynolds, Kaycee N; Loecke, Terrance D; Burgin, Amy J; Davis, Caroline A; Riveros-Iregui, Diego; Thomas, Steven A; St Clair, Martin A; Ward, Adam S

    2016-06-21

    Understanding linked hydrologic and biogeochemical processes such as nitrate loading to agricultural streams requires that the sampling bias and precision of monitoring strategies be known. An existing spatially distributed, high-frequency nitrate monitoring network covering ∼40% of Iowa provided direct observations of in situ nitrate concentrations at a temporal resolution of 15 min. Systematic subsampling of nitrate records allowed for quantification of uncertainties (bias and precision) associated with estimates of various nitrate parameters, including: mean nitrate concentration, proportion of samples exceeding the nitrate drinking water standard (DWS), peak (>90th quantile) nitrate concentration, and nitrate flux. We subsampled continuous records for 47 site-year combinations mimicking common, but labor-intensive, water-sampling regimes (e.g., time-interval, stage-triggered, and dynamic-discharge storm sampling). Our results suggest that time-interval sampling most efficiently characterized all nitrate parameters, except at coarse frequencies for nitrate flux. Stage-triggered storm sampling most precisely captured nitrate flux when less than 0.19% of possible 15 min observations for a site-year were used. The time-interval strategy had the greatest return on sampling investment by most precisely and accurately quantifying nitrate parameters per sampling effort. These uncertainty estimates can aid in designing sampling strategies focused on nitrate monitoring in the tile-drained Midwest or similar agricultural regions.

  19. Ground-water movement and nitrate in ground water, East Erda area, Tooele County, Utah, 1997-2000

    USGS Publications Warehouse

    Susong, D.D.

    2005-01-01

    Nitrate was discovered in ground water in the east Erda area of Tooele County, Utah, in 1994. The U.S. Geological Survey, in cooperation with Tooele County, investigated the ground-water flow system and water quality in the eastern part of Tooele Valley to determine (1) the vertical and horizontal distribution of nitrate, (2) the direction of movement of the nitrate contamination, and (3) the source of the nitrate. The potentiometric surface of the upper part of the basin-fill aquifer indicates that the general direction of ground-water flow is to the northwest, the flow system is complex, and there is a ground-water mound probably associated with springs. The spatial distribution of nitrate reflects the flow system with the nitrate contamination split into a north and south part by the ground-water mound. The distribution of dissolved solids and sulfate in ground water varies spatially. Vertical profiles of nitrate in water from selected wells indicate that nitrate contamination generally is in the upper part of the saturated zone and in some wells has moved downward. Septic systems, mining and smelting, agriculture, and natural sources were considered to be possible sources of nitrate contamination in the east Erda area. Septic systems are not the source of nitrate because water from wells drilled upgradient of all septic systems in the area had elevated nitrate concentrations. Mining and smelting activity are a possible source of nitrate contamination but few data are available to link nitrate contamination with mining sites. Natural and agricultural sources of nitrate are present east of the Erda area but few data are available about these sources. The source(s) of nitrate in the east Erda area could not be clearly delineated in spite of considerable effort and expenditure of resources.

  20. Simulating land management options to reduce nitrate pollution in an agricultural watershed dominated by an alluvial aquifer.

    PubMed

    Cerro, Itsasne; Antigüedad, Iñaki; Srinavasan, Raghavan; Sauvage, Sabine; Volk, Martin; Sanchez-Perez, José Miguel

    2014-01-01

    The study area (Alegria watershed, Basque Country, Northern Spain) considered here is influenced by an important alluvial aquifer that plays a significant role in nitrate pollution from agricultural land use and management practices. Nitrates are transported primarily from the soil to the river through the alluvial aquifer. The agricultural activity covers 75% of the watershed and is located in a nitrate-vulnerable zone. The main objective of the study was to find land management options for water pollution abatement by using model systems. In a first step, the SWAT model was applied to simulate discharge and nitrate load in stream flow at the outlet of the catchment for the period between October 2009 and June 2011. The LOADEST program was used to estimate the daily nitrate load from measured nitrate concentration. We achieved satisfactory simulation results for discharge and nitrate loads at monthly and daily time steps. The results revealed clear variations in the seasons: higher nitrate loads were achieved for winter (20,000 kg mo NO-N), and lower nitrate loads were simulated for the summer (<1000 kg mo NO-N) period. In a second step, the calibrated model was used to evaluate the long-term effects of best management practices (BMPs) for a 50-yr period by maintaining actual agricultural practices, reducing fertilizer application by 20%, splitting applications (same total N but applied over the growing period), and reducing 20% of the applied fertilizer amount and splitting the fertilizer doses. The BMPs were evaluated on the basis of local experience and farmer interaction. Results showed that reducing fertilizer amounts by 20% could lead to a reduction of 50% of the number of days exceeding the nitrate concentration limit value (50 mg L) set by the European Water Framework Directive. PMID:25602541

  1. Influence of soil and climate heterogeneity on the performance of economic instruments for reducing nitrate leaching from agriculture.

    PubMed

    Peña-Haro, Salvador; García-Prats, Alberto; Pulido-Velazquez, Manuel

    2014-11-15

    Economic instruments can be used to control groundwater nitrate pollution due to the intensive use of fertilizers in agriculture. In order to test their efficiency on the reduction of nitrate leaching, we propose an approach based on the combined use of production and pollution functions to derive the impacts on the expected farmer response of these instruments. Some of the most important factors influencing nitrate leaching and crop yield are the type of soil and the climatic conditions. Crop yield and nitrate leaching responses to different soil and climatic conditions were classified by means of a cluster analysis, and crops located in different areas but with similar response were grouped for the analysis. We use a spatial economic optimization model to evaluate the potential of taxes on nitrogen fertilizers, water prices, and taxes on nitrate emissions to reduce nitrate pollution, as well as their economic impact in terms of social welfare and farmers' net benefits. The method was applied to the Mancha Oriental System (MOS) in Spain, a large area with different soil types and climatic conditions. We divided the study area into zones of homogeneous crop production and nitrate leaching properties. Results show spatially different responses of crop growth and nitrate leaching, proving how the cost-effectiveness of pollution control instruments is contingent upon the spatial heterogeneities of the problem.

  2. 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.

  3. High resolution modeling of agricultural nitrogen to identify private wells susceptible to nitrate contamination.

    PubMed

    Hoppe, Brendalynn; White, Denis; Harding, Anna; Mueller-Warrant, George; Hope, Bruce; Main, Eric

    2014-12-01

    Given the lack of data on private wells, public health and water quality specialists must explore alternative datasets for understanding associated exposures and health risks. Characterizing agricultural nitrogen inputs would be valuable for identifying areas where well water safety may be compromised. This study incorporated existing methods for estimating nutrient loading at the county level with datasets derived from a state permitting program for confined animal feeding operations and agricultural enterprise budget worksheets to produce a high resolution agricultural nitrogen raster map. This map was combined with data on soil leachability and new well locations. An algorithm was developed to calculate nitrogen loading and leachability within 1,000 meters of each well. Wells with a nonzero nitrogen total linked to soils with high leachability were categorized and displayed on maps communicating well susceptibility across the state of Oregon. Results suggest that 4% of recently drilled wells may be susceptible to nitrate contamination, while areas identified for mitigation are too restrictive to include all susceptible wells. Predicted increases in population density and the steady addition of approximately 3,800 new wells annually may lead to a large number of residents, especially those in rural areas, experiencing long-term exposures to nitrate in drinking water. PMID:25473979

  4. Nitrate pollution from agriculture in different hydrogeological zones of the regional groundwater flow system in the North China Plain

    NASA Astrophysics Data System (ADS)

    Chen, Jianyao; Tang, Changyuan; Sakura, Yasuo; Yu, Jingjie; Fukushima, Yoshihiro

    2005-06-01

    A survey of the quality of groundwater across a broad area of the North China Plain, undertaken in 1998 to 2000, indicates that nitrate pollution is a serious problem affecting the drinking water for a vast population. The use of nitrogen (N)-fertilizer in agriculture has greatly increased over the past 20 years to meet the food needs of the rapidly expanding population. During the study, 295 water samples were collected from wells and springs to determine the water chemistry and the extent of nitrate pollution. High concentrations of nitrate, especially in a recharge area along the western side, but also in the vicinity of Beijing and locally in other parts of the plain, pose a serious problem for the drinking water supply. In places, the nitrate concentration exceeds the maximum for safe drinking water of 45 mg/L. The intense use of N-fertilizer and the widespread use of untreated groundwater for crop irrigation contribute greatly to the problem, but no doubt the disposal of industrial and municipal waste into streams and infiltrating the aquifer also contribute to the problem; however, the lack of data prevents evaluation of those sources. In the recharge area, nitrate is found at depths of as much as 50 m. Near Beijing, relatively high concentrations of nitrate occur at depths of as much as 80 m. In the discharge area, in the vicinity of the Yellow River, high concentrations of nitrate occur at depths of <8 m.

  5. Agriculture's Contribution to Nitrate Contamination of Californian Groundwater (1945-2005).

    PubMed

    Rosenstock, Todd S; Liptzin, Daniel; Dzurella, Kristin; Fryjoff-Hung, Anna; Hollander, Allan; Jensen, Vivian; King, Aaron; Kourakos, George; McNally, Alison; Pettygrove, G Stuart; Quinn, Jim; Viers, Joshua H; Tomich, Thomas P; Harter, Thomas

    2014-05-01

    Nitrogen (N) use in intensive agriculture can degrade groundwater resources. However, considerable time lags between groundwater recharge and extraction complicate source attribution and remedial responses. We construct a historic N mass balance of two agricultural regions of California to understand trends and drivers of past and present N loading to groundwater (1945-2005). Changes in groundwater N loading result from historic changes in three factors: the extent of agriculture (cropland area and livestock herd increased 120 and 800%, respectively), the intensity of agriculture (synthetic and manure waste effluent N input rates increased by 525 and 1500%, respectively), and the efficiency of agriculture (crop and milk production per unit of N input increased by 25 and 19%, respectively). The net consequence has been a greater-than-order-of-magnitude increase in nitrate (NO) loading over the time period, with 163 Gg N yr now being leached to groundwater from approximately 1.3 million ha of farmland (not including alfalfa [ L.]). Meeting safe drinking water standards would require NO leaching reductions of over 70% from current levels through reductions in excess manure applications, which accounts for nearly half of all groundwater N loading, and through synthetic N management improvements. This represents a broad challenge given current economic and technical conditions of California farming if farm productivity is to be maintained. The findings illustrate the growing tension-characteristic of agricultural regions globally-between intensifying food, feed, fiber, and biofuel production and preserving clean water.

  6. Nitrate Leaching from Intensive Fiber Production on Abandoned Agricultural Land

    SciTech Connect

    Williams, T.M.

    1999-01-01

    Paper outlines nitrate leaching results of loblolly pine and sweet gum that were grown with irrigation, continuous fertilization and insect pest control on a year old abandoned peanut field. Wells and tension lysimeters were used to measure nitrate in soil moisture and groundwater on three replicate transects for two years. Groundwater nitrate concentration beneath the minimum treatment was much higher than the maximum treatment and old field. All three treatments often exceeded the drinking water standard. Forest and lake edge had low levels while the soil moisture nitrate concentrations in the two plantation treatments were much higher than the old field.

  7. Monthly variability and possible sources of nitrate in ground water beneath mixed agricultural land use, Suwannee and Lafayette Counties, Florida

    USGS Publications Warehouse

    Katz, Brian G.; Böhlke, J.K.

    2000-01-01

    In an area of mixed agricultural land use in Suwannee and Lafayette Counties of northern Florida, water samples were collected monthly from 14 wells tapping the Upper Floridan aquifer during July 1998 through June 1999 to assess hydrologic and land-use factors affecting the variability in nitrate concentrations in ground water. Unusually high amounts of rainfall in September and October 1998 (43.5 centimeters total for both months) resulted in an increase in water levels in all wells in October 1998. This was followed by unusually low amounts of rainfall during November 1998 through May 1999, when rainfall was 40.7 centimeters below 30-year mean monthly values. The presence of karst features (sinkholes, springs, solution conduits) and the highly permeable sands that overlie the Upper Floridan aquifer provide for rapid movement of water containing elevated nitrate concentrations to the aquifer. Nitrate was the dominant form of nitrogen in ground water collected at all sites and nitrate concentrations ranged from less than 0.02 to 22 milligrams per liter (mg/L), as nitrogen. Water samples from most wells showed substantial monthly or seasonal fluctuations in nitrate concentrations. Generally, water samples from wells with nitrate concentrations higher than 10 mg/L showed the greatest amount of monthly fluctuation. For example, water samples from six of eight wells had monthly nitrate concentrations that varied by at least 5 mg/L during the study period. Water from most wells with lower nitrate concentrations (less than 6 mg/L) also showed large monthly fluctuations. For instance, nitrate concentrations in water from four sites showed monthly variations of more than 50 percent. Large fluctuations in nitrate concentrations likely result from seasonal agricultural practices (fertilizer application and animal waste spreading) at a particular site. For example, an increase in nitrate concentrations observed in water samples from seven sites in February or March 1999 most

  8. Modeling the long-term fate of agricultural nitrate in groundwater in the San Joaquin Valley, California

    USGS Publications Warehouse

    Chapelle, Francis H.; Campbell, Bruce G.; Widdowson, Mark A.; Landon, Mathew K.

    2013-01-01

    Nitrate contamination of groundwater systems used for human water supplies is a major environmental problem in many parts of the world. Fertilizers containing a variety of reduced nitrogen compounds are commonly added to soils to increase agricultural yields. But the amount of nitrogen added during fertilization typically exceeds the amount of nitrogen taken up by crops. Oxidation of reduced nitrogen compounds present in residual fertilizers can produce substantial amounts of nitrate which can be transported to the underlying water table. Because nitrate concentrations exceeding 10 mg/L in drinking water can have a variety of deleterious effects for humans, agriculturally derived nitrate contamination of groundwater can be a serious public health issue. The Central Valley aquifer of California accounts for 13 percent of all the groundwater withdrawals in the United States. The Central Valley, which includes the San Joaquin Valley, is one of the most productive agricultural areas in the world and much of this groundwater is used for crop irrigation. However, rapid urbanization has led to increasing groundwater withdrawals for municipal public water supplies. That, in turn, has led to concern about how contaminants associated with agricultural practices will affect the chemical quality of groundwater in the San Joaquin Valley. Crop fertilization with various forms of nitrogen-containing compounds can greatly increase agricultural yields. However, leaching of nitrate from soils due to irrigation has led to substantial nitrate contamination of shallow groundwater. That shallow nitrate-contaminated groundwater has been moving deeper into the Central Valley aquifer since the 1960s. Denitrification can be an important process limiting the mobility of nitrate in groundwater systems. However, substantial denitrification requires adequate sources of electron donors in order to drive the process. In many cases, dissolved organic carbon (DOC) and particulate organic carbon

  9. Economic Analysis of Nitrate Source Reductions in California Agriculture

    NASA Astrophysics Data System (ADS)

    Medellin-Azuara, J.; Howitt, R.; Rosenstock, T.; Harter, T.; Pettygrove, S. G.; Dzurella, K.; Lund, J. R.

    2011-12-01

    We present an analytical approach to assess the economic impact of improving nitrogen management practices in California agriculture. We employ positive mathematical programming to calibrate crop production to base input information. The production function representation is a nested constant elasticity of substitution with two nests: one for applied water and one for applied nitrogen. The first nest accounts for the tradeoffs between irrigation efficiency and capital investments in irrigation technology. The second nest represents the tradeoffs between nitrogen application efficiency and the marginal costs of improving nitrogen efficiency. In the production function nest, low elasticities of substitution and water and nitrogen stress constraints keep agricultural crop yields constant despite changes in nitrogen management practices. We use the Tulare Basin, and the Salinas Valley in California's Central Valley and Central Coast respectively as our case studies. Preliminary results show that initial reductions of 25% in nitrogen loads to groundwater may not impose large costs to agricultural crop production as substitution of management inputs results in only small declines in net revenue from farming and total land use. Larger reductions in the nitrogen load to groundwater of 50% imposes larger marginal costs for better nitrogen management inputs and reductions in the area of lower valued crops grown in the study areas. Despite the shortage of data on quantitative effects of improved nitrogen efficiency; our results demonstrate the potential of combining economic and agronomic data into a model that can reflect differences in cost and substitutabilty in nitrogen application methods, that can be used to reduce the quantity of nitrogen leaching into groundwater.

  10. Effects of agriculture production systems on nitrate and nitrite accumulation on baby-leaf salads

    PubMed Central

    Aires, Alfredo; Carvalho, Rosa; Rosa, Eduardo A S; Saavedra, Maria J

    2013-01-01

    Nitrate and nitrite are widespread contaminants of vegetables, fruits, and waters. The levels of these compounds are increased as a result of using organic wastes from chemical industries, domestic wastes, effluents, nitrogenous fertilizers, and herbicides in agriculture. Therefore, determining the nitrate and nitrite levels in biological, food, and environmental samples is important to protect human health and the environment. In this context, we set this study, in which we report the effect of production system (conventional and organic) on the accumulation of nitrates and nitrites in fresh baby-leaf samples. The average levels of the nitrate () and nitrite () contents in six different baby-leaf salads of a single species (green lettuce, red lettuce, watercress, rucola, chard, and corn salad) produced in organic and conventional agriculture system were evaluated. Spectrophotometric analytical method recently published was validated and used. Nitrates and nitrites were detected in all samples. The nitrates levels from organic production varied between 1.45 and 6.40 mg/kg fresh weight (FW), whereas those from conventional production ranged from 10.5 to 45.19 mg/kg FW. The nitrites content was lower than nitrates and ranged from 0.32 to 1.89 mg/kg FW in organic production system and between 0.14 and 1.41 mg/kg FW in conventional production system. Our results showed that the nitrate content was dependent on the agricultural production system, while for nitrites, this dependency was less pronounced. PMID:24804008

  11. Nitrate dynamics in agricultural catchments deduced from groundwater dating and long-term nitrate monitoring in surface- and groundwaters.

    PubMed

    Aquilina, L; Vergnaud-Ayraud, V; Labasque, T; Bour, O; Molénat, J; Ruiz, L; de Montety, V; De Ridder, J; Roques, C; Longuevergne, L

    2012-10-01

    Although nitrate export in agricultural catchments has been simulated using various types of models, the role of groundwater in nitrate dynamics has rarely been fully taken into account. We used groundwater dating methods (CFC analyses) to reconstruct the original nitrate concentrations in the groundwater recharge in Brittany (Western France) from 1950 to 2009. This revealed a sharp increase in nitrate concentrations from 1977 to 1990 followed by a slight decrease. The recharge concentration curve was then compared with past chronicles of groundwater concentration. Groundwater can be interpreted as resulting from the annual dilution of recharge water in an uncontaminated aquifer. Two aquifers were considered: the weathered aquifer and the deeper fractured aquifer. The nitrate concentrations observed in the upper part of the weathered aquifer implied an annual renewal rate of 27 to 33% of the reservoir volume while those in the lower part indicated an annual renewal rate of 2-3%. The concentrations in the deep fractured aquifer showed an annual renewal rate of 0.1%. The river concentration can be simulated by combining these various groundwater reservoirs with the recharge. Winter and summer waters contain i) recharge water, or water from the variably saturated zone with rapid transfer and high nitrate concentrations, and ii) a large contribution (from 35 to 80% in winter and summer, respectively) from the lower part of the aquifer (lower weathered aquifer and deep fractured aquifer). This induces not only a relatively rapid response of the catchment to variations in agricultural pressure, but also a potential inertia which has to be taken into account.

  12. 77 FR 59377 - Solid Agricultural Grade Ammonium Nitrate from Ukraine: Final Results of the Expedited Second...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-27

    ... Five-Year (``Sunset'') Review, 77 FR 32527 (June 1, 2012). The Department received a notice of intent... International Trade Administration Solid Agricultural Grade Ammonium Nitrate from Ukraine: Final Results of the... of initiation of the second sunset review of the antidumping duty order on solid agricultural...

  13. Groundwater Nitrate Contamination Risk Assessment in Canicattì area (Sicily)

    NASA Astrophysics Data System (ADS)

    Pisciotta, Antonino; Cusimano, Gioacchino; Favara, Rocco

    2010-05-01

    Groundwaters play a dominant role in the Sicily, because as most part of Mediterranean countries this island is interested by the phenomenon of desertification and the quality of the groundwater reservoir is one of the most important aim for the management policy strategies. During last decade most of the Italian regions the nitrate levels in river and groundwaters have increased gradually over mainly as a consequence of large-scale agricultural application of manure and fertilizers, thereby threatening drinking water quality. The excessive use of chemicals and fertilizers increases the risk to pollution of surface and groundwater from diffuse source, an important reflex to human health and the environment. The studied area is located in Canicattì (central Sicily, Italy), the current land use (grape, olive grove and almond) is the main source of groundwater pollution. In order to investigate the effect of the over farming on the groundwater quality we report the study on the potential risk of contamination from nitrate of agricultural origin through the join of the application of two parametric methods: the IPNOA method (the intrinsic nitrate contamination risk from Agricultural sources) applied to define the Nitrate Vulnerable Zones and the SINTACS method applied to determine the aquifer vulnerability to contamination.

  14. Modeling approaches to management of nitrate contamination of groundwater in a heavily cultivated area

    NASA Astrophysics Data System (ADS)

    Koh, E.; Park, Y.; Lee, K.

    2011-12-01

    A three-dimensional variably-saturated groundwater flow and reactive transport modeling framework was implemented to simulate nitrate contamination in a heavily cultivated area in Jeju volcanic Island. In the study area, two localized aquifer systems (perched and regional groundwater) exist due to distributions of impermeable clay layers beneath the perched groundwater. The approximate application rate of chemical fertilizers was surveyed to be 627.9 kg-N/ha per year, which is much higher than the average annual chemical fertilizer usage in Jeju Island, 172 kg-N/ha per year. Severe nitrate contamination has been observed in the perched groundwater system and such perched groundwater has influenced regional groundwater quality, through poorly cemented wall of the distributed throughout the region wells. For a part of managing plan of nitrate contamination in the island, a numerical modeling framework was developed for various scenarios associated with the factors affecting nitrate contamination in the study area (i.e., usage amount of chemical fertilizers, cultivated methods, grouting condition of wells). This work provides useful information to suggest effective ways to manage nitrate contamination of groundwater in the agricultural field. Acknowledgements: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011-0001120) and by BK21 project of Korean Government.

  15. Managing farming systems for nitrate control: a research review from management systems evaluation areas.

    PubMed

    Power, J F; Wiese, R; Flowerday, D

    2001-01-01

    The U.S. Department of Agriculture funded the Management Systems Evaluation Area (MSEA) research project in 1990 to evaluate effectiveness of present farming systems in controlling nitrate N in water resources and to develop improved technologies for farming systems. This paper summarizes published research results of a five-year effort. Most research is focused on evaluating the effectiveness of farming system components (fertilizer, tillage, water control, cropping systems, and soil and weather variability). The research results show that current soil nitrate tests reliably predict fertilizer N needed to control environmental and economic risks for crop production. A corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation usually controls risk better than continuous corn, but both may result in unacceptable nitrate leaching. Reduced tillage, especially ridge-till, is better than clean tillage in reducing risk. Tile drainage controls nitrate in ground water, but discharge may increase nitrate in surface waters. Sprinkler irrigation systems provide better water control than furrow irrigation because quantity and spatial variability of applied water is reduced. Present farming systems have two major deficiencies: (i) entire fields are managed uniformly, ignoring inherent soil variability within a field; and (ii) N fertilizer rates and many field practices are selected assuming normal weather for the coming season. Both deficiencies can contribute to nitrate leaching in parts of most fields. PMID:11789991

  16. The changing trend in nitrate concentrations in major aquifers due to historical nitrate loading from agricultural land across England and Wales from 1925 to 2150.

    PubMed

    Wang, L; Stuart, M E; Lewis, M A; Ward, R S; Skirvin, D; Naden, P S; Collins, A L; Ascott, M J

    2016-01-15

    Nitrate is necessary for agricultural productivity, but can cause considerable problems if released into aquatic systems. Agricultural land is the major source of nitrates in UK groundwater. Due to the long time-lag in the groundwater system, it could take decades for leached nitrate from the soil to discharge into freshwaters. However, this nitrate time-lag has rarely been considered in environmental water management. Against this background, this paper presents an approach to modelling groundwater nitrate at the national scale, to simulate the impacts of historical nitrate loading from agricultural land on the evolution of groundwater nitrate concentrations. An additional process-based component was constructed for the saturated zone of significant aquifers in England and Wales. This uses a simple flow model which requires modelled recharge values, together with published aquifer properties and thickness data. A spatially distributed and temporally variable nitrate input function was also introduced. The sensitivity of parameters was analysed using Monte Carlo simulations. The model was calibrated using national nitrate monitoring data. Time series of annual average nitrate concentrations along with annual spatially distributed nitrate concentration maps from 1925 to 2150 were generated for 28 selected aquifer zones. The results show that 16 aquifer zones have an increasing trend in nitrate concentration, while average nitrate concentrations in the remaining 12 are declining. The results are also indicative of the trend in the flux of groundwater nitrate entering rivers through baseflow. The model thus enables the magnitude and timescale of groundwater nitrate response to be factored into source apportionment tools and to be taken into account alongside current planning of land-management options for reducing nitrate losses. PMID:26546765

  17. Regional analysis of groundwater nitrate concentrations and trends in Denmark in regard to agricultural influence

    NASA Astrophysics Data System (ADS)

    Hansen, B.; Dalgaard, T.; Thorling, L.; Sørensen, B.; Erlandsen, M.

    2012-08-01

    The act of balancing between an intensive agriculture with a high potential for nitrate pollution and a drinking water supply almost entirely based on groundwater is a challenge faced by Denmark and similar regions around the globe. Since the 1980s, regulations implemented by Danish farmers have succeeded in optimizing the N (nitrogen) management at farm level. As a result, the upward agricultural N surplus trend has been reversed, and the N surplus has reduced by 30-55% from 1980 to 2007 depending on region. The reduction in the N surplus served to reduce the losses of N from agriculture, with documented positive effects on nature and the environment in Denmark. In groundwater, the upward trend in nitrate concentrations was reversed around 1980, and a larger number of downward nitrate trends were seen in the youngest groundwater compared with the oldest groundwater. However, on average, approximately 48% of the oxic monitored groundwater has nitrate concentrations above the groundwater and drinking water standards of 50 mg l-1. Furthermore, trend analyses show that 33% of all the monitored groundwater has upward nitrate trends, while only 18% of the youngest groundwater has upward nitrate trends according to data sampled from 1988-2009. A regional analysis shows a correlation between a high level of N surplus in agriculture, high concentrations of nitrate in groundwater and the largest number of downward nitrate trends in groundwater in the livestock-dense northern and western parts of Denmark compared with the southeastern regions with lower livestock densities. These results indicate that the livestock farms dominating in northern and western parts of Denmark have achieved the largest reductions in N surpluses. Groundwater recharge age determinations allow comparison of long-term changes in N surplus in agriculture with changes in oxic groundwater quality. The presented data analysis is based on groundwater recharged from 1952-2003, but sampled from 1988

  18. Regional analysis of groundwater nitrate concentrations and trends in Denmark in regard to agricultural influence

    NASA Astrophysics Data System (ADS)

    Hansen, B.; Dalgaard, T.; Thorling, L.; Sørensen, B.; Erlandsen, M.

    2012-05-01

    The act of balancing between an intensive agriculture with a high potential for nitrate pollution and a~drinking water supply almost entirely based on groundwater is a challenge faced by Denmark and similar regions around the globe. Since the 1980s, regulations implemented by Danish farmers have succeeded in optimizing the N (nitrogen) management at farm level. As a result, the upward agricultural N surplus trend has been reversed, and the N surplus has reduced by 30-55 % from 1980 to 2007 depending on region. The reduction in the N surplus served to reduce the losses of N from agriculture, with documented positive effects on nature and the environment in Denmark. In groundwater, the upward trend in nitrate concentration was reversed around 1980, and a larger number of downward nitrate trends were seen in the youngest groundwater compared with the oldest groundwater. However, on average, approximately 48 % of the oxic monitored groundwater has nitrate concentrations above the groundwater and drinking water standards of 50 mg l-1. Furthermore, trend analyses show that 33 % of all the monitored groundwater has upward nitrate trends, while only 18 % of the youngest groundwater has upward nitrate trends according to data sampled from 1988-2009. A regional analysis shows a correlation between a high level of N surplus in agriculture, high concentrations of nitrate in groundwater and the largest number of downward nitrate trends in groundwater in the livestock-dense northern and western parts of Denmark compared with the south-eastern regions with lower livestock densities. These results indicate that the livestock farms dominating in northern and western parts of Denmark have achieved the largest reductions in N surpluses. Groundwater recharge age determinations allow comparison of long-term changes in N surplus in agriculture with changes in oxic groundwater quality. The presented data analysis is based on groundwater recharged from 1952-2003, but sampled from 1988

  19. Identifying sources of groundwater nitrate contamination in a large alluvial groundwater basin with highly diversified intensive agricultural production.

    PubMed

    Lockhart, K M; King, A M; Harter, T

    2013-08-01

    Groundwater quality is a concern in alluvial aquifers underlying agricultural areas worldwide. Nitrate from land applied fertilizers or from animal waste can leach to groundwater and contaminate drinking water resources. The San Joaquin Valley, California, is an example of an agricultural landscape with a large diversity of field, vegetable, tree, nut, and citrus crops, but also confined animal feeding operations (CAFOs, here mostly dairies) that generate, store, and land apply large amounts of liquid manure. As in other such regions around the world, the rural population in the San Joaquin Valley relies almost exclusively on shallow domestic wells (≤150 m deep), of which many have been affected by nitrate. Variability in crops, soil type, and depth to groundwater contribute to large variability in nitrate occurrence across the underlying aquifer system. The role of these factors in controlling groundwater nitrate contamination levels is examined. Two hundred domestic wells were sampled in two sub-regions of the San Joaquin Valley, Stanislaus and Merced (Stan/Mer) and Tulare and Kings (Tul/Kings) Counties. Forty six percent of well water samples in Tul/Kings and 42% of well water samples in Stan/Mer exceeded the MCL for nitrate (10mg/L NO3-N). For statistical analysis of nitrate contamination, 78 crop and landuse types were considered by grouping them into ten categories (CAFO, citrus, deciduous fruits and nuts, field crops, forage, native, pasture, truck crops, urban, and vineyards). Vadose zone thickness, soil type, well construction information, well proximity to dairies, and dominant landuse near the well were considered. In the Stan/Mer area, elevated nitrate levels in domestic wells most strongly correlate with the combination of very shallow (≤21 m) water table and the presence of either CAFO derived animal waste applications or deciduous fruit and nut crops (synthetic fertilizer applications). In Tulare County, statistical data indicate that elevated

  20. Identifying sources of groundwater nitrate contamination in a large alluvial groundwater basin with highly diversified intensive agricultural production

    NASA Astrophysics Data System (ADS)

    Lockhart, K. M.; King, A. M.; Harter, T.

    2013-08-01

    Groundwater quality is a concern in alluvial aquifers underlying agricultural areas worldwide. Nitrate from land applied fertilizers or from animal waste can leach to groundwater and contaminate drinking water resources. The San Joaquin Valley, California, is an example of an agricultural landscape with a large diversity of field, vegetable, tree, nut, and citrus crops, but also confined animal feeding operations (CAFOs, here mostly dairies) that generate, store, and land apply large amounts of liquid manure. As in other such regions around the world, the rural population in the San Joaquin Valley relies almost exclusively on shallow domestic wells (≤ 150 m deep), of which many have been affected by nitrate. Variability in crops, soil type, and depth to groundwater contribute to large variability in nitrate occurrence across the underlying aquifer system. The role of these factors in controlling groundwater nitrate contamination levels is examined. Two hundred domestic wells were sampled in two sub-regions of the San Joaquin Valley, Stanislaus and Merced (Stan/Mer) and Tulare and Kings (Tul/Kings) Counties. Forty six percent of well water samples in Tul/Kings and 42% of well water samples in Stan/Mer exceeded the MCL for nitrate (10 mg/L NO3-N). For statistical analysis of nitrate contamination, 78 crop and landuse types were considered by grouping them into ten categories (CAFO, citrus, deciduous fruits and nuts, field crops, forage, native, pasture, truck crops, urban, and vineyards). Vadose zone thickness, soil type, well construction information, well proximity to dairies, and dominant landuse near the well were considered. In the Stan/Mer area, elevated nitrate levels in domestic wells most strongly correlate with the combination of very shallow (≤ 21 m) water table and the presence of either CAFO derived animal waste applications or deciduous fruit and nut crops (synthetic fertilizer applications). In Tulare County, statistical data indicate that elevated

  1. Identifying sources of groundwater nitrate contamination in a large alluvial groundwater basin with highly diversified intensive agricultural production.

    PubMed

    Lockhart, K M; King, A M; Harter, T

    2013-08-01

    Groundwater quality is a concern in alluvial aquifers underlying agricultural areas worldwide. Nitrate from land applied fertilizers or from animal waste can leach to groundwater and contaminate drinking water resources. The San Joaquin Valley, California, is an example of an agricultural landscape with a large diversity of field, vegetable, tree, nut, and citrus crops, but also confined animal feeding operations (CAFOs, here mostly dairies) that generate, store, and land apply large amounts of liquid manure. As in other such regions around the world, the rural population in the San Joaquin Valley relies almost exclusively on shallow domestic wells (≤150 m deep), of which many have been affected by nitrate. Variability in crops, soil type, and depth to groundwater contribute to large variability in nitrate occurrence across the underlying aquifer system. The role of these factors in controlling groundwater nitrate contamination levels is examined. Two hundred domestic wells were sampled in two sub-regions of the San Joaquin Valley, Stanislaus and Merced (Stan/Mer) and Tulare and Kings (Tul/Kings) Counties. Forty six percent of well water samples in Tul/Kings and 42% of well water samples in Stan/Mer exceeded the MCL for nitrate (10mg/L NO3-N). For statistical analysis of nitrate contamination, 78 crop and landuse types were considered by grouping them into ten categories (CAFO, citrus, deciduous fruits and nuts, field crops, forage, native, pasture, truck crops, urban, and vineyards). Vadose zone thickness, soil type, well construction information, well proximity to dairies, and dominant landuse near the well were considered. In the Stan/Mer area, elevated nitrate levels in domestic wells most strongly correlate with the combination of very shallow (≤21 m) water table and the presence of either CAFO derived animal waste applications or deciduous fruit and nut crops (synthetic fertilizer applications). In Tulare County, statistical data indicate that elevated

  2. Precipitation changes impact stream discharge, nitrate-nitrogen load more than agricultural management changes.

    PubMed

    Nangia, V; Mulla, D J; Gowda, P H

    2010-01-01

    Nitrate-N losses to surface waters in the Upper Midwest of the Untied States have increased in recent decades, contributing to hypoxia in the Gulf of Mexico. This paper investigates whether increasing nitrate-N export from cropland in the Upper Midwest since the late 1960s results from changes in land use or climate. The Agricultural Drainage and Pesticide Transport (ADAPT) Model simulated current and historical agricultural systems under past and recent wet climate for Seven Mile Creek in Minnesota. Simulations were run with management and climate for three distinctly different periods--namely, 1965 to 1969, 1976 to 1980, and 1999 to 2003 (wettest period). Results showed discharge and nitrate-N losses responded more to changes in climate than management. The wetter period (1999-2003) caused a simulated 70% increase in discharge under 1960s-era management compared with that period's observed climate and a simulated 51% increase in discharge under 1970s-era management compared with the 1976 to 1980 climate. The recent, wetter climate also produced a 62% increase in nitrate-N losses for 1960s-era management compared with the actual climate and a 137% increase in nitrate-N losses for 1978 management conditions compared with actual 1970s climate. Had recent climate been in place and stable since 1965, agricultural changes would have decreased discharge by 6.4% through the late 1970s and then by another 21.1% under modern management but would have increased nitrate-N losses by 184% through the late 1970s and then decreased nitrate-N losses by 13.5% between 1978 and 2001. Management changes that were important drivers included increasing N-fertilizer rates, increases in corn acreage, and increases in crop yield. But the most important factor driving increased nitrate-N losses from agriculture since the 1970s was an increasingly wetter climate.

  3. Nitrate nitrogen in surface waters as influenced by climatic conditions and agricultural practices.

    PubMed

    Randall, G W; Mulla, D J

    2001-01-01

    Subsurface tile drainage from row-crop agricultural production systems has been identified as a major source of nitrate entering surface waters in the Mississippi River basin. Noncontrollable factors such as precipitation and mineralization of soil organic matter have a tremendous effect on drainage losses, nitrate concentrations, and nitrate loadings in subsurface drainage water. Cropping system and nutrient management inputs are controllable factors that have a varying influence on nitrate losses. Row crops leak substantially greater amounts of nitrate compared with perennial crops; however, satisfactory economic return with many perennials is an obstacle at present. Improving N management by applying the correct rate of N at the optimum time and giving proper credits to previous legume crops and animal manure applications will also lead to reduced nitrate losses. Nitrate losses have been shown to be minimally affected by tillage systems compared with N management practices. Scientists and policymakers must understand these factors as they develop educational materials and environmental guidelines for reducing nitrate losses to surface waters. PMID:11285893

  4. Assessment of groundwater vulnerability to nitrates from agricultural sources using a GIS-compatible logic multicriteria model.

    PubMed

    Rebolledo, Boris; Gil, Antonia; Flotats, Xavier; Sánchez, José Ángel

    2016-04-15

    In the present study an overlay method to assess groundwater vulnerability is proposed. This new method based on multicriteria decision analysis (MCDA) was developed and validated using an appropriate case study in Aragon area (NE Spain). The Vulnerability Index to Nitrates from Agricultural Sources (VINAS) incorporates a novel Logic Scoring of Preferences (LSP) approach, and it has been developed using public geographic information from the European Union. VINAS-LSP identifies areas with five categories of vulnerability, taking into account the hydrogeological and environmental characteristics of the territory as a whole. The resulting LSP map is a regional screening tool that can provide guidance on the potential risk of nitrate pollution, as well as highlight areas where specific research and farming planning policies are required. PMID:26874616

  5. Assessment of groundwater vulnerability to nitrates from agricultural sources using a GIS-compatible logic multicriteria model.

    PubMed

    Rebolledo, Boris; Gil, Antonia; Flotats, Xavier; Sánchez, José Ángel

    2016-04-15

    In the present study an overlay method to assess groundwater vulnerability is proposed. This new method based on multicriteria decision analysis (MCDA) was developed and validated using an appropriate case study in Aragon area (NE Spain). The Vulnerability Index to Nitrates from Agricultural Sources (VINAS) incorporates a novel Logic Scoring of Preferences (LSP) approach, and it has been developed using public geographic information from the European Union. VINAS-LSP identifies areas with five categories of vulnerability, taking into account the hydrogeological and environmental characteristics of the territory as a whole. The resulting LSP map is a regional screening tool that can provide guidance on the potential risk of nitrate pollution, as well as highlight areas where specific research and farming planning policies are required.

  6. Diurnal variation of dominant nitrate retention processes in an agricultural headwater stream

    NASA Astrophysics Data System (ADS)

    Schuetz, Tobias; Ryabenko, Evgenia; Stumpp, Christine

    2015-04-01

    Nitrate and ammonium are introduced by agricultural practice into the environment and are transformed and retained on their pathway through aquatic environments. In particular, biological transformation processes (i.e. microbial denitrification or ammonium oxidation and assimilation) are responsible for the largest part of nitrate removal, which are also crucial processes in headwater streams. It is well known, that most of the biological processes are influenced by available (solar) energy fluxes, temperatures and dissolved oxygen concentrations, which vary with time and space. However, looking at biogeochemical hot spots in the landscapes` hydrological interface, the stream and river network (e.g. stream sections with a high biological activity), the temporal variability of biological processes can be an important control on total nitrate export. In this study, we therefore identified most important diurnal time periods for nitrate retention in a 75 m impervious section of an agricultural headwater stream using oxygen saturation dynamics and nitrate isotopes. We regularly measured discharge, hydro-geochemical and climate parameters, as well as nitrate and water isotopes in grab samples at three locations along the reach. On average, we observed a decrease of 10% in nitrate concentration from up- to downstream, which was only caused by biological processes and not by dilution. Nitrate isotope analysis indicated distinct trends along the reach and with time of the day. Both nitrate assimilation and nitrification caused significant changes in nitrate isotope distribution in the early day. To explain the distinct observed process dynamics from the morning to the afternoon, we simulated net primary production (NEP) and respiration using the river metabolism model RIVERMETC with observed oxygen concentrations and water temperatures. Comparing the results with the observed nitrate dynamics, the short time period when NEP occurs (~10:30 -12:30) seems to be crucial for

  7. Humic Acid-Oxidizing, Nitrate-Reducing Bacteria in Agricultural Soils

    PubMed Central

    Van Trump, J. Ian; Wrighton, Kelly C.; Thrash, J. Cameron; Weber, Karrie A.; Andersen, Gary L.; Coates, John D.

    2011-01-01

    ABSTRACT This study demonstrates the prevalence, phylogenetic diversity, and physiology of nitrate-reducing microorganisms capable of utilizing reduced humic acids (HA) as electron donors in agricultural soils. Most probable number (MPN) enumeration of agricultural soils revealed large populations (104 to 106 cells g−1 soil) of microorganisms capable of reducing nitrate while oxidizing the reduced HA analog 2,6-anthrahydroquinone disulfonate (AH2DS) to its corresponding quinone. Nitrate-dependent HA-oxidizing organisms isolated from agricultural soils were phylogenetically diverse and included members of the Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. Advective up-flow columns inoculated with corn plot soil and amended with reduced HA and nitrate supported both HA oxidation and enhanced nitrate reduction relative to no-donor or oxidized HA controls. The additional electron donating capacity of reduced HA could reasonably be attributed to the oxidation of reduced functional groups. Subsequent 16S rRNA gene-based high-density oligonucleotide microarray (PhyloChip) indicated that reduced HA columns supported the development of a bacterial community enriched with members of the Acidobacteria, Firmicutes, and Betaproteobacteria relative to the no-donor control and initial inoculum. This study identifies a previously unrecognized role for HA in stimulating denitrification processes in saturated soil systems. Furthermore, this study indicates that reduced humic acids impact soil geochemistry and the indigenous bacterial community composition. PMID:21750120

  8. Groundwater nitrate concentration evolution under climate change and agricultural adaptation scenarios: Prince Edward Island, Canada

    NASA Astrophysics Data System (ADS)

    Paradis, Daniel; Vigneault, Harold; Lefebvre, René; Savard, Martine M.; Ballard, Jean-Marc; Qian, Budong

    2016-03-01

    Nitrate (N-NO3) concentration in groundwater, the sole source of potable water in Prince Edward Island (PEI, Canada), currently exceeds the 10 mg L-1 (N-NO3) health threshold for drinking water in 6 % of domestic wells. Increasing climatic and socio-economic pressures on PEI agriculture may further deteriorate groundwater quality. This study assesses how groundwater nitrate concentration could evolve due to the forecasted climate change and its related potential changes in agricultural practices. For this purpose, a tridimensional numerical groundwater flow and mass transport model was developed for the aquifer system of the entire Island (5660 km2). A number of different groundwater flow and mass transport simulations were made to evaluate the potential impact of the projected climate change and agricultural adaptation. According to the simulations for year 2050, N-NO3 concentration would increase due to two main causes: (1) the progressive attainment of steady-state conditions related to present-day nitrogen loadings, and (2) the increase in nitrogen loadings due to changes in agricultural practices provoked by future climatic conditions. The combined effects of equilibration with loadings, climate and agricultural adaptation would lead to a 25 to 32 % increase in N-NO3 concentration over the Island aquifer system. The change in groundwater recharge regime induced by climate change (with current agricultural practices) would only contribute 0 to 6 % of that increase for the various climate scenarios. Moreover, simulated trends in groundwater N-NO3 concentration suggest that an increased number of domestic wells (more than doubling) would exceed the nitrate drinking water criteria. This study underlines the need to develop and apply better agricultural management practices to ensure sustainability of long-term groundwater resources. The simulations also show that observable benefits from positive changes in agricultural practices would be delayed in time due to

  9. Analysis and evaluation of nitrate levels in groundwater at Al-Hashimiya area, Jordan.

    PubMed

    Obeidat, Mutewekil M; Massadeh, Adnan M; Al-Ajlouni, Ahmad M; Athamneh, Faisal S

    2007-12-01

    Water with high nitrate concentration (NO(3) (-)) is unfit for human consumption, especially when its concentration exceeded the threshold limit (50 mg/l) recommended by the health authorities such as the World Health Organization (WHO). In Jordan, there is a great concern for determination and monitoring organic and inorganic pollutants that may reach groundwater. Nitrate is highly mobile and present in domestic, agricultural and industrial waste in Jordan, and thus this study focused initially on nitrate as both a contaminant of concern and as an indicator of potential groundwater contamination. The present study determined the extent of nitrate contamination in groundwater in the study area and examined the likely sources of NO(3) (-). A total of 248 groundwater samples were collected from 16 wells in different sites of Al-Hashimiya area, Zerqa Governorate, Jordan, and investigated for NO(3) (-) concentrations. Moreover, measurements of temperature, electrical conductivity and pH were carried out in the field. Analysis was carried out according to the methods described by the American Public Health Association (APHA). Results showed that there was a dramatic increasing in NO(3) (-) concentrations from the year 2001 to 2006 for some selected wells in the present study. NO(3) (-) concentration in 2006 was ranged from 10 to 330 mg/l with an average of 77 mg/l. Overall, groundwater had elevated nitrate concentration with 92% of the samples containing more than 20 mg/l NO(3) (-), indicating the influence of human activities. This study has shown that there is a strong correlation between the nitrate concentration and the wastewater effluents as a source of pollution.

  10. Turbidity and nitrate transfer in karstic aquifers in rural areas: the Brionne Basin case-study.

    PubMed

    Nebbache, S; Feeny, V; Poudevigne, I; Alard, D

    2001-08-01

    The degradation of water quality in many groundwaters of Europe is a major source of concern. Rises in turbidity and nitrate concentrations represent present or potential threats for the quality of drinking water in rural areas. They are for the most part a consequence of agricultural intensification which has considerably affected land cover and land use in recent decades. In our case-study (a karstic catchment) the mechanisms which explain changes in water quality, as far as turbidity and nitrate are concerned, result from a strong continuity between surface and underground waters. The karstic system of the Brionne Basin can be considered as both the focus of rapid horizontal flows (runoff, a rapid process in which rainwater reaches the spring directly through sinkholes) and slow vertical flows (leaching, in which rainwater filters through the soil to the spring). A hierarchical approach to the water pollution problem of the basin suggests that turbidity or nitrate concentrations peak during heavy rain episodes and are short-term events. In terms of management, this implies that the solution to water pollution caused by such events is also short-term and can therefore be addressed at a local scale. The rise of nitrate concentrations during the past twenty years is the main concern. The solution can only be found at a global scale (all the catchment area must be taken in account: land plots and their spatial configuration), and by taking a long-term approach.

  11. Groundwater nitrate concentration evolution under climate change and agricultural adaptation scenarios: Prince Edward Island, Canada

    NASA Astrophysics Data System (ADS)

    Paradis, D.; Vigneault, H.; Lefebvre, R.; Savard, M. M.; Ballard, J.-M.; Qian, B.

    2015-08-01

    Nitrate (N-NO3) concentration in groundwater, the sole source of potable water in Prince Edward Island (PEI, Canada), currently exceeds the 10 mg L-1 (N-NO3) health threshold for drinking water in 6 % of domestic wells. Increasing climatic and socio-economic pressures on PEI agriculture may further deteriorate groundwater quality. This study assesses how groundwater nitrate concentrations could evolve due to the forecasted climate change and its related potential changes in agricultural practices. For this purpose, a tridimensional numerical groundwater flow and mass transport model was developed for the aquifer system of the entire Island (5660 km2). A number of different groundwater flow and mass transport simulations were made to evaluate the potential impact of the projected climate change and agricultural adaptation. According to the simulations for year 2050, N-NO3 concentration would increase due to two main causes: (1) the progressive attainment of steady-state conditions related to present-day nitrogen loadings, and (2) the increase in nitrogen loadings due to changes in agricultural practices provoked by future climatic conditions. The combined effects of equilibration with loadings, climate and agricultural adaptation would lead to a 25 to 32 % increase in N-NO3 concentration over the Island aquifer system. Climate change alone (practices maintained at their current level) would contribute only 0 to 6 % to that increase according to the various climate scenarios. Moreover, simulated trends in groundwater N-NO3 concentration suggest that an increased number of domestic wells (more than doubling) would exceed the nitrate drinking water criteria. This study underlines the need to develop and apply better agricultural management practices to ensure sustainability of long-term groundwater resources. The simulations also show that observable benefits from positive changes in agricultural practices would be delayed in time due to the slow dynamics of nitrate

  12. Assessment of rural ground-water contamination by agricultural chemicals in sensitive areas of Michigan

    SciTech Connect

    Ervin, J.L.; Kittleson, K.M.

    1988-04-01

    The vulnerability of drinking-water supplies to agricultural contamination in three Michigan counties is discussed. The results of nitrate and atrazine analysis of drinking water from 38 wells in those 3 counties is described. Widespread nitrate contamination was demonstrated in agricultural areas with vulnerable aquifers. In addition, atrazine, a widely used herbicide was found in 11 of the 38 wells samples, with concentrations and patterns not conforming to findings in other mid-western states. The need for a comprehensive inventory of the ground-water quality in rural areas of Michigan is emphasized in the report, which describes results from the first year of a 2-year study.

  13. Disentangling the influence of hydroclimatic patterns and agricultural management on river nitrate dynamics from sub-hourly to decadal time scales.

    PubMed

    Dupas, Rémi; Jomaa, Seifeddine; Musolff, Andreas; Borchardt, Dietrich; Rode, Michael

    2016-11-15

    Despite extensive efforts to reduce nitrate transfer in agricultural areas, limited response is often observed in the nitrate concentration in rivers. To investigate the reasons for this limited response, nitrate dynamics in a 100km(2) agricultural catchment in eastern Germany was analysed from sub-hourly to decadal time-scales. Sub-hourly analysis of storm event dynamics during a typical hydrological year (2005-2006) was performed to identify periods of the year with high leaching risk and to link the latter to agricultural management practices in the catchment. Dynamic Harmonic Regression analysis of a 32-year (1982-2014) record of nitrate and discharge revealed that i) the long-term trend in nitrate concentration was closely related to that in discharge, suggesting that large-scale weather and climate patterns were masking the effect of improved nitrogen management on nitrate trends; ii) a persistent seasonal pattern with winter concentration maxima and summer minima could be observed, which was interpreted in terms of a dynamic nitrate concentration profile in the soil and subsoil; and iii) the catchment progressively changed from chemodynamic to more chemostatic behaviour over the three decades of study, which is a sign of long-term homogenisation of nitrate concentrations distribution over depth. This study shows that detailed physical understanding of nitrate dynamics across time scales can be obtained only through combined analysis of long-term records and high-resolution sensor data. Hence, a joint effort is advocated between environmental authorities, who usually perform long-term monitoring, and scientific programmes, which usually perform high-resolution monitoring. PMID:27422723

  14. Disentangling the influence of hydroclimatic patterns and agricultural management on river nitrate dynamics from sub-hourly to decadal time scales.

    PubMed

    Dupas, Rémi; Jomaa, Seifeddine; Musolff, Andreas; Borchardt, Dietrich; Rode, Michael

    2016-11-15

    Despite extensive efforts to reduce nitrate transfer in agricultural areas, limited response is often observed in the nitrate concentration in rivers. To investigate the reasons for this limited response, nitrate dynamics in a 100km(2) agricultural catchment in eastern Germany was analysed from sub-hourly to decadal time-scales. Sub-hourly analysis of storm event dynamics during a typical hydrological year (2005-2006) was performed to identify periods of the year with high leaching risk and to link the latter to agricultural management practices in the catchment. Dynamic Harmonic Regression analysis of a 32-year (1982-2014) record of nitrate and discharge revealed that i) the long-term trend in nitrate concentration was closely related to that in discharge, suggesting that large-scale weather and climate patterns were masking the effect of improved nitrogen management on nitrate trends; ii) a persistent seasonal pattern with winter concentration maxima and summer minima could be observed, which was interpreted in terms of a dynamic nitrate concentration profile in the soil and subsoil; and iii) the catchment progressively changed from chemodynamic to more chemostatic behaviour over the three decades of study, which is a sign of long-term homogenisation of nitrate concentrations distribution over depth. This study shows that detailed physical understanding of nitrate dynamics across time scales can be obtained only through combined analysis of long-term records and high-resolution sensor data. Hence, a joint effort is advocated between environmental authorities, who usually perform long-term monitoring, and scientific programmes, which usually perform high-resolution monitoring.

  15. Nitrate-Nitrogen Leaching and Modeling in Intensive Agriculture Farmland in China

    PubMed Central

    Xu, Ligang; Xu, Jin

    2013-01-01

    Protecting water resources from nitrate-nitrogen (NO3-N) contamination is an important public health concern and a major national environmental issue in China. Loss of NO3-N in soils due to leaching is not only one of the most important problems in agriculture farming, but is also the main factor causing nitrogen pollution in aquatic environments. Three typical intensive agriculture farmlands in Jiangyin City in China are selected as a case study for NO3-N leaching and modeling in the soil profile. In this study, the transport and fate of NO3-N within the soil profile and nitrate leaching to drains were analyzed by comparing field data with the simulation results of the LEACHM model. Comparisons between measured and simulated data indicated that the NO3-N concentrations in the soil and nitrate leaching to drains are controlled by the fertilizer practice, the initial conditions and the rainfall depth and distribution. Moreover, the study reveals that the LEACHM model gives a fair description of the NO3-N dynamics in the soil and subsurface drainage at the field scale. It can also be concluded that the model after calibration is a useful tool to optimize as a function of the combination “climate-crop-soil-bottom boundary condition” the nitrogen application strategy resulting for the environment in an acceptable level of nitrate leaching. The findings in this paper help to demonstrate the distribution and migration of nitrogen in intensive agriculture farmlands, as well as to explore the mechanism of groundwater contamination resulting from agricultural activities. PMID:23983629

  16. Nitrate-nitrogen leaching and modeling in intensive agriculture farmland in China.

    PubMed

    Xu, Ligang; Niu, Hailin; Xu, Jin; Wang, Xiaolong

    2013-01-01

    Protecting water resources from nitrate-nitrogen (NO3-N) contamination is an important public health concern and a major national environmental issue in China. Loss of NO3-N in soils due to leaching is not only one of the most important problems in agriculture farming, but is also the main factor causing nitrogen pollution in aquatic environments. Three typical intensive agriculture farmlands in Jiangyin City in China are selected as a case study for NO3-N leaching and modeling in the soil profile. In this study, the transport and fate of NO3-N within the soil profile and nitrate leaching to drains were analyzed by comparing field data with the simulation results of the LEACHM model. Comparisons between measured and simulated data indicated that the NO3-N concentrations in the soil and nitrate leaching to drains are controlled by the fertilizer practice, the initial conditions and the rainfall depth and distribution. Moreover, the study reveals that the LEACHM model gives a fair description of the NO3-N dynamics in the soil and subsurface drainage at the field scale. It can also be concluded that the model after calibration is a useful tool to optimize as a function of the combination "climate-crop-soil-bottom boundary condition" the nitrogen application strategy resulting for the environment in an acceptable level of nitrate leaching. The findings in this paper help to demonstrate the distribution and migration of nitrogen in intensive agriculture farmlands, as well as to explore the mechanism of groundwater contamination resulting from agricultural activities.

  17. MAJOR AGRICULTURAL MIGRANT LABOR DEMAND AREAS.

    ERIC Educational Resources Information Center

    Department of Labor, Washington, DC.

    DEPICTED ARE 12 CHARTS OF MAJOR CROP PRODUCTION CENTERS IN THE UNITED STATES WHICH DEMAND THE LABOR OF MIGRATORY FARM WORKERS THROUGHOUT THE YEAR. EACH CHART ILLUSTRATES THE AREAS OF AGRICULTURAL MIGRANT LABOR DEMAND FOR ONE MONTH OF THE YEAR. THE PURPOSE IS TO ACQUAINT THE PUBLIC WITH THE COMPLEXITY OF PLACING AND SCHEDULING MIGRATORY WORKERS…

  18. Decadal geochemical and isotopic trends for nitrate in a transboundary aquifer and implications for agricultural beneficial management practices.

    PubMed

    Wassenaar, Leonard I; Hendry, M Jim; Harrington, Nikki

    2006-08-01

    Nitrate contamination of aquifers is a global agricultural problem. Agricultural beneficial management practices (BMPs) are often promoted as a means to reduce nitrate contamination in aquifers through producer optimized management of inorganic fertilizer and animal manure inputs. In this study, decadal trends (1991-2004) in nitrate concentrations in conjunction with 3H/3He groundwater ages and nitrate stable isotopes (delta15N, delta18O) were examined to determine whether BMPs aimed at reducing aquifer-scale nitrate contamination in the transboundary Abbotsford-Sumas aquifer were effective. A general trend of increasing nitrate concentrations in young groundwater (< approximately 5 yr) suggested that voluntary BMPs were not having a positive impact in achieving groundwater quality targets. While the stable isotope data showed that animal manure was and still is the prevalent source of nitrate in the aquifer, a recent decrease in delta15N in nitrate suggests a BMP driven shift away from animal wastes toward inorganic fertilizers. The coupling of long-term monitoring of nitrate concentrations, nitrate isotopes, and 3H/3He age dating proved to be invaluable, and they should be considered in future assessments of the impact of BMPs on nutrients in groundwaters. The findings reveal that BMPs should be better linked to groundwater nutrient monitoring programs in order to more quickly identify BMP deficiencies, and to dynamically adjust nutrient loadings to help achieve water quality objectives.

  19. Nitrate

    Integrated Risk Information System (IRIS)

    Nitrate ; CASRN 14797 - 55 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects

  20. Enhanced removal of nitrate from water using amine-grafted agricultural wastes.

    PubMed

    Kalaruban, Mahatheva; Loganathan, Paripurnanda; Shim, W G; Kandasamy, Jaya; Ngo, H H; Vigneswaran, Saravanamuthu

    2016-09-15

    Adsorption using low-cost adsorbents is a favourable water treatment method for the removal of water contaminants. In this study the enhanced removal of nitrate, a contaminant at elevated concentration affecting human health and causing eutrophication of water, was tested using chemically modified agricultural wastes as adsorbents. Batch and fixed-bed adsorption studies were performed on corn cob and coconut copra that were surface modified by amine-grafting to increase the surface positive charges. The Langmuir nitrate adsorption capacities (mgN/g) were 49.9 and 59.0 for the amine-grafted (AG) corn cob and coconut copra, respectively at pH6.5 and ionic strength 1×10(-3)M NaCl. These values are higher than those of many commercially available anion exchange resins. Fixed-bed (15-cm height) adsorption capacities (mgN/g) calculated from the breakthrough curves were 15.3 and 18.6 for AG corn cob and AG coconut copra, respectively, for an influent nitrate concentration 20mg N/L at a flow velocity 5m/h. Nitrate adsorption decreased in the presence of sulphate, phosphate and chloride, with sulphate being the most competitive anion. The Thomas model fitted well to the fixed-bed adsorption data from four repeated adsorption/desorption cycles. Plug-flow model fitted well to the data from only the first cycle.

  1. Enhanced removal of nitrate from water using amine-grafted agricultural wastes.

    PubMed

    Kalaruban, Mahatheva; Loganathan, Paripurnanda; Shim, W G; Kandasamy, Jaya; Ngo, H H; Vigneswaran, Saravanamuthu

    2016-09-15

    Adsorption using low-cost adsorbents is a favourable water treatment method for the removal of water contaminants. In this study the enhanced removal of nitrate, a contaminant at elevated concentration affecting human health and causing eutrophication of water, was tested using chemically modified agricultural wastes as adsorbents. Batch and fixed-bed adsorption studies were performed on corn cob and coconut copra that were surface modified by amine-grafting to increase the surface positive charges. The Langmuir nitrate adsorption capacities (mgN/g) were 49.9 and 59.0 for the amine-grafted (AG) corn cob and coconut copra, respectively at pH6.5 and ionic strength 1×10(-3)M NaCl. These values are higher than those of many commercially available anion exchange resins. Fixed-bed (15-cm height) adsorption capacities (mgN/g) calculated from the breakthrough curves were 15.3 and 18.6 for AG corn cob and AG coconut copra, respectively, for an influent nitrate concentration 20mg N/L at a flow velocity 5m/h. Nitrate adsorption decreased in the presence of sulphate, phosphate and chloride, with sulphate being the most competitive anion. The Thomas model fitted well to the fixed-bed adsorption data from four repeated adsorption/desorption cycles. Plug-flow model fitted well to the data from only the first cycle. PMID:27192699

  2. Flood survey of nitrate behaviour using nitrogen isotope tracing in the critical zone of a French agricultural catchment

    NASA Astrophysics Data System (ADS)

    Paul, Alexia; Moussa, Issam; Payre, Virginie; Probst, Anne; Probst, Jean-Luc

    2015-11-01

    Measurements of δ15N-NO3- were taken in a highly flood-responsive agricultural catchment in the southwest of France to trace the sources and transfer pathways of nitrates during flood events. From January to March 2013, surface water samples were collected every week at the outlet, and four floods were sampled with a high resolution. Sampling was also performed in surface waters and sand lenses from the rest of the basin to trace nitrate sources and processes spatially. Nitrate extractions were performed using a method based on the solubility difference between inorganic salts and organic solutions. The δ15N values were in the range of surface water contaminated by N-fertilisers. Depending on the hydroclimatic event, nitrates resulted from a combination of sources and processes. At the start of the floods, the values of δ15N-NO3- and nitrate concentrations were low, demonstrating the dilution of water with rainwater. During a second phase, the nitrate concentration and the δ15N were higher. Deeper waters and soil solutions were the second source of nitrates. When the water level was low, both nitrate concentration and isotopic composition were high. These values reflected the denitrification processes that occurred in the soil under anaerobic conditions. An analysis of δ15N-NO3- in stream water in a small agricultural catchment was efficient at determining the origin of nitrates during flood events using a simple method.

  3. Revealing organic carbon-nitrate linear relationship from UV spectra of freshwaters in agricultural environment.

    PubMed

    Thomas, O; Jung, A V; Causse, J; Louyer, M V; Piel, S; Baurès, E; Thomas, M F

    2014-07-01

    A strong non linear relationship between nitrate and organic matter (assessed by dissolved organic carbon, DOC) has been recently demonstrated by Taylor and Townsend (2010), namely for freshwaters. In this context, our study explores this relation from the behavior of sets of normalized UV spectra (same area under each spectrum) of different water samples showing a hidden isosbestic point (HIP) around 225 nm. This HIP is linked to the existence of a simple relation between nitrate and DOC, the proportions of which vary according to the sampling location and environmental factors. In a second step, a simple linear model is proposed for nitrate-DOC relationship (α⋅NO3+β⋅DOC=1) and a validation is proposed for more than 150 samples of different Brittany rivers and lakes. For samples of the largest watershed, a complementary exploitation from data acquired during the different campaigns confirmed the seasonal evolution between spring (high nitrate/low DOC) and autumn (high DOC/low nitrate). Further investigation on other freshwater samples is needed in order to improve the limits of this linear model. PMID:24875878

  4. Revealing organic carbon-nitrate linear relationship from UV spectra of freshwaters in agricultural environment.

    PubMed

    Thomas, O; Jung, A V; Causse, J; Louyer, M V; Piel, S; Baurès, E; Thomas, M F

    2014-07-01

    A strong non linear relationship between nitrate and organic matter (assessed by dissolved organic carbon, DOC) has been recently demonstrated by Taylor and Townsend (2010), namely for freshwaters. In this context, our study explores this relation from the behavior of sets of normalized UV spectra (same area under each spectrum) of different water samples showing a hidden isosbestic point (HIP) around 225 nm. This HIP is linked to the existence of a simple relation between nitrate and DOC, the proportions of which vary according to the sampling location and environmental factors. In a second step, a simple linear model is proposed for nitrate-DOC relationship (α⋅NO3+β⋅DOC=1) and a validation is proposed for more than 150 samples of different Brittany rivers and lakes. For samples of the largest watershed, a complementary exploitation from data acquired during the different campaigns confirmed the seasonal evolution between spring (high nitrate/low DOC) and autumn (high DOC/low nitrate). Further investigation on other freshwater samples is needed in order to improve the limits of this linear model.

  5. Relation of distribution of radium, nitrate, and pesticides to agricultural land use and depth, kirkwood-cohansey aquifer system, New Jersey coastal plain, 1990-91. Water-resources investigations

    SciTech Connect

    Szabo, Z.; Rice, D.E.; MacLeod, C.L.; Barringer, T.H.

    1997-12-31

    This report examines the relation of the distributions of dissolved radium, nitrate, and pesticides in the aquifer to the distribution of agricultural land and to depth in agricultural areas in the Coastal Plain of southern New Jersey. The report also discusses the geochemistry of the aquifer system and evaluates possible geochemical processes that result in the leaching of radium into solution.

  6. Use of a Metolachlor Metabolite (MESA) to Assess Agricultural Nitrate-N Fate and Transport in Choptank River Watershed, Maryland USA

    NASA Astrophysics Data System (ADS)

    McCarty, Greg; Hapeman, Cathleen; Rice, Clifford; Hively, Dean; McConnell, Laura; Sadeghi, Ali; Lang, Megan; Whitall, David; Bialek, Krystyna; Downey, Peter

    2014-05-01

    A majority of streams in the Chesapeake Bay watershed have been rated as poor or very poor based on biological assessments. The Choptank River estuary, a Bay tributary on the eastern shore, is an example, where crop production in upland areas of the watershed contribute significant loads of nutrients to streams. We used a novel approach based on the relationship between the concentration of nitrate-N and the stable, water-soluble herbicide degradation product MESA {2-[2-ethyl-N-(1-methoxypropan-2-yl) -6-methylanilino]-2-oxoethanesulfonic acid} to distinguish between dilution and denitrification effects on the stream concentration of nitrate-N in agricultural subwatersheds. The ratio of mean nitrate-N concentration/(mean MESA concentration * 1000) for 15 subwatersheds was examined as a function of percent cropland on hydric soil. The observed inverse relationship (R2 = 0.65, p < 0.001) accounts for not only dilution and denitrification of nitrate-N, but also the stream sampling bias of the croplands caused by extensive drainage ditch networks. MESA was also used to track nitrate-N fate within the estuary of the Choptank River. The relationship between nitrate-N and MESA concentrations in samples collected over three years was linear (0.95 ≤ R2 ≤ 0.99) for all eight sampling dates except one where R2 = 0.90. This very strong correlation indicates that nitrate-N was conserved in much of the Choptank River estuary, that dilution alone is responsible for the changes in nitrate-N and MESA concentrations, and more importantly nitrate-N loads are not reduced in the estuary prior to entering the Chesapeake Bay.

  7. Influence of Antecedent Hydrologic Conditions on Nitrate and Phosphorus Export from a Small Agricultural Catchment in Southern Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Macrae, M. L.; English, M. C.; Schiff, S. L.; Stone, M.

    2009-04-01

    The ability of the scientific community to quantify and predict discharge and nutrient transport in a range of settings is confounded by the effects of antecedent hydrologic conditions in upland areas. Previous work has empirically linked spatial variables such as land use, soil type, topography, and drainage characteristics to hydrochemical export from various landscapes (e.g. MCDOWELL et al., 2001; ARHEIMER and LIDEN, 2000; STAMM et al., 1998; JORDAN et al., 1997; WELSCH et al., 2001). However, the specific reasons why similar types of events produce different nutrient export patterns are poorly understood. Nutrient (nitrate, soluble and total phosphorus) transport from agricultural catchments is difficult to quantify and predict because of the influence of variable hydrologic flowpaths and their interaction with varying nutrient pools. This research examines the role of antecedent hydrologic conditions on stream discharge and nitrate (NO3-), soluble reactive phosphorus (SRP) and total phosphorus (TP) export from a small (2.7 km2) first-order agricultural catchment in Southern Ontario, Canada. During 59 events occurring over a two-year sampling period (year-round), runoff ratios ranged from 0-0.99). Runoff ratios increased throughout successive events as conditions became wetter although key indices of antecedent wetness such as water table position, pre-event streamflow and soil moisture did not yield predictive relationships. Nitrate, SRP and TP transport from the catchment increased with antecedent wetness during some periods but decreased with antecedent wetness during other periods. This variability appears to be linked to a combination of the position of water table before and during the event, as well as timing of fertilizer application. It is hypothesized that in general, wetter antecedent hydrologic conditions increase nutrient transport from the catchment by increasing macropore connectivity between surface soil horizons and tile drains, although this

  8. Transport and Fate of Nitrate in Shallow Aquifers in Contrasting Agricultural Settings across the US.

    NASA Astrophysics Data System (ADS)

    Green, C. T.; Puckett, L. J.; Bohlke, J. F.; Phillips, S. P.; Denver, J. M.

    2006-05-01

    The fate of nitrate in four shallow aquifers was investigated with combined laboratory analyses, field measurements, and flow and transport modeling. In the summer of 2003, groundwater wells were installed along kilometer-scale transects in small, predominantly agricultural watersheds at four sites: the San Joaquin Valley, California; central Nebraska; the Yakima River basin, Washington; and the Delmarva Peninsula, Maryland. Groundwater data collected at these sites included potentiometric head, major element chemistry, nutrients, organic carbon, dissolved gases, nitrogen and oxygen isotopes in dissolved nitrate and nitrogen gas, and age dating tracers including chlorofluorocarbons, sulfur hexafluoride, and tritium. Sediment data included particle size distributions, organic matter content, and nitrogen and carbon isotopes of surface soils. For each site, 3-D flow and conservative transport of groundwater age tracers were simulated using boundary conditions interpolated from regional models. All sites had nitrate detections exceeding the Environmental Protection Agency's Maximum Contaminant Level (MCL) of 10 mg/L. At Maryland and California the median concentrations were above the MCL. At the study unit scale, sites with higher excess nitrogen gas concentrations tended to have older groundwater and lower dissolved oxygen. Concentrations of stable isotopes and excess dissolved nitrogen gas indicate little or no denitrifying activity at the Maryland and Washington sites, partial denitrification at the California site, and total denitrification across much of the Nebraska site. Estimates of age and excess nitrogen gas imply gradual denitrification rates of 1.4 ug NO3-N per day at the California site and a portion of the Nebraska site. Elsewhere at the Nebraska site, more rapid, complete denitrification occurs near the water table. The collected results from all four sites indicate that denitrification rates are highly variable and are only reliable for mitigating

  9. Fertilizer standards for controlling groundwater nitrate pollution from agriculture: El Salobral-Los Llanos case study, Spain

    NASA Astrophysics Data System (ADS)

    Peña-Haro, S.; Llopis-Albert, C.; Pulido-Velazquez, M.; Pulido-Velazquez, D.

    2010-10-01

    SummaryAlthough the legislation on groundwater quality targets pollutant concentration, the effects of measures on non-point source pollution control are often evaluated in terms of their emission reduction potential at the source, not on their capacity of reducing the pollutant concentration in groundwater. This paper applies a hydro-economic modelling framework to an aquifer, El Salobral-Los Llanos aquifer (Mancha Oriental, Spain), where nitrate concentrations higher than those allowed by the EU Water Framework Directive and Groundwater Directive are locally found due to the intense fertilizer use in irrigated crops. The approach allows defining the economically optimal allocation of spatially variable fertilizer standards in agricultural basins using a hydro-economic model that links the fertilizer application with groundwater nitrate concentration at different control sites while maximizing net economic benefits. The methodology incorporates results from agronomic simulations, groundwater flow and transport into a management framework that yields the fertilizer allocation that maximizes benefits in agriculture while meeting the environmental standards. The cost of applying fertilizer standards was estimated as the difference between the private net revenues from actual application and the scenarios generated considering the application of the standards. Furthermore, the cost of applying fertilizer standards was compared with the cost of taxing nitrogen fertilizers in order to reduce the fertilizer use to a level that the nitrate concentration in groundwater was below the limit. The results show the required reduction of fertilizer application in the different crop areas depending on its location with regards to the control sites, crop types and soil-plant conditions, groundwater flow and transport processes, time horizon for meeting the standards, and the cost of implementing such a policy (as forgone benefits). According to the results, a high fertilizer price

  10. Nitrate behaviors and source apportionment in an aquatic system from a watershed with intensive agricultural activities.

    PubMed

    Lu, Lu; Cheng, Hongguang; Pu, Xiao; Liu, Xuelian; Cheng, Qianding

    2015-01-01

    Nitrate pollution in aquatic systems caused by intensive agricultural activities is a serious problem in the Sanjiang Plain. In this study, a dual isotope approach (δ(15)N-NO3(-) and δ(18)O-NO3(-)) was employed to identify potential nitrate sources (atmospheric deposition, AD; NO3(-) derived from soil organic matter nitrification, NS; NO3(-) derived from chemical fertilizer nitrification, NF; and manure and sewage, M&S) and transformation processes occurring in the Abujiao River watershed located in the Sanjiang Plain. The Bayesian model (stable isotope analysis in R, SIAR) was utilized to apportion the contribution of the potential sources. In this watershed, the nitrate concentrations in the surface water were low (mean ± SD = 1.15 ± 0.84 mg L(-1)), and were greatly influenced by precipitation and land use conditions during the two sampling periods (the high flow period, September; the low flow period, November). On the contrary, in the ground water, high NO3(-) concentrations were observed (7.84 ± 5.83 mg L(-1)) and no significant temporal variation in NO3(-) was found during the sampling periods. The sampled water δ(18)O-NO3(-) values suggest that the nitrification process was not the main N cycling process, because most of the measured δ(18)O-NO3(-) values were above the expected δ(18)O-NO3(-) from nitrification throughout the sampling periods. Both the chemical and isotopic characteristics indicated that the signs of de-nitrification were absent in the surface water. However, significant de-nitrification processes were observed in the ground water for all sample periods. Results from the SIAR model showed that source contributions differed significantly during the two sampling periods. During the high flow period, chemical fertilizers and soil N fertilizer equally contributed to the major sources of nitrate in the surface water. In contrast, manure and sewage sources dominated the source contribution during the low flow period (November). This study

  11. Influence of Nitrate on the Hanford 100D Area In Situ Redox Manipulation Barrier Longevity

    SciTech Connect

    Szecsody, Jim E.; Phillips, Jerry L.; Vermeul, Vince R.; Fruchter, Jonathan S.; Williams, Mark D.

    2005-07-15

    The purpose of this laboratory study is to determine the influence of nitrate on the Hanford 100D Area in situ redox manipulation (ISRM) barrier longevity. There is a wide spread groundwater plume of 60 mg/L nitrate upgradient of the ISRM barrier with lower nitrate concentrations downgradient, suggestive of nitrate reduction occurring. Batch and 1-D column experiments showed that nitrate is being slowly reduced to nitrite and ammonia. These nitrate reduction reactions are predominantly abiotic, as experiments with and without bactericides present showed no difference in nitrate degradation rates. Nitrogen species transformation rates determined in experiments covered a range of ferrous iron/nitrate ratios such that the data can be used to predict rates in field scale conditions. Field scale reaction rate estimates for 100% reduced sediment (16 C) are: (a) nitrate degradation = 202 {+-} 50 h (half-life), (b) nitrite production = 850 {+-} 300 h, and (c) ammonia production = 650 {+-} 300 h. Calculation of the influence of nitrate reduction on the 100D Area reductive capacity requires consideration of mass balance and reaction rate effects. While dissolved oxygen and chromate reduction rates are rapid and essentially at equilibrium in the aquifer, nitrate transformation reactions are slow (100s of hours). In the limited (20-40 day) residence time in the ISRM barrier, only a portion of the nitrate will be reduced, whereas dissolved oxygen and chromate are reduced to completion. Assuming a groundwater flow rate of 1 ft/day, it is estimated that the ISRM barrier reductive capacity is 160 pore volumes (with no nitrate), and 85 pore volumes if 60 mg/L nitrate is present (i.e., a 47% decrease in the ISRM barrier longevity). Zones with more rapid groundwater flow will be less influenced by nitrate reduction. For example, a zone with a groundwater flow rate of 3 ft/day and 60 mg/L nitrate will have a reductive capacity of 130 pore volumes. Finally, long-term column experiments

  12. The feasibility of applying immature yard-waste compost to remove nitrate from agricultural drainage effluents: A preliminary assessment

    USGS Publications Warehouse

    Tsui, L.; Krapac, I.G.; Roy, W.R.

    2007-01-01

    Nitrate is a major agricultural pollutant found in drainage waters. Immature yard-waste compost was selected as a filter media to study its feasibility for removing nitrate from drainage water. Different operation parameters were tested to examine the denitrification efficiency, including the amounts of compost packed in columns, the flow rate, and the compost storage periods. The experimental results suggested that hydraulic retention time was the major factor to determine the extent of nitrate removal, although the amount of compost packed could also contribute to the nitrate removal efficiency. The effluent nitrate concentration increased as the flow rate decreased, and the compost column reduced nitrate concentrations from 20 mg/L to less than 5 mg/L within 1.5 h. The solution pH increased at the onset of experiment because of denitrification, but stabilized at a pH of about 7.8, suggesting that the compost had a buffering capacity to maintain a suitable pH for denitrification. Storing compost under air-dried conditions may diminish the extent nitrate removed initially, but the effects were not apparent after longer applications. It appeared that immature yard-waste compost may be a suitable material to remove nitrate from tile drainage water because of its relatively large organic carbon content, high microbial activity, and buffering capacity. ?? 2006 Elsevier B.V. All rights reserved.

  13. Nitrate fate and transport through current and former depressional wetlands in an agricultural landscape, Choptank Watershed, Maryland, United States

    USGS Publications Warehouse

    Denver, J.M.; Ator, S.W.; Lang, M.W.; Fisher, T.R.; Gustafson, A.B.; Fox, R.; Clune, J.W.; McCarty, G.W.

    2014-01-01

    Understanding local groundwater hydrology and geochemistry is critical for evaluating the effectiveness of wetlands at mitigating agricultural impacts on surface waters. The effectiveness of depressional wetlands at mitigating nitrate (NO3) transport from fertilized row crops, through groundwater, to local streams was examined in the watershed of the upper Choptank River, a tributary of Chesapeake Bay on the Atlantic Coastal Plain. Hydrologic, geochemical, and water quality data were collected from January of 2008 through December of 2009 from surface waters and networks of piezometers installed in and around current or former depressional wetlands of three major types along a gradient of anthropogenic alteration: (1) natural wetlands with native vegetation (i.e., forested); (2) prior-converted croplands, which are former wetlands located in cultivated fields; and (3) hydrologically restored wetlands, including one wetland restoration and one shallow water management area. These data were collected to estimate the orientation of groundwater flow paths and likely interactions of groundwater containing NO3 from agricultural sources with reducing conditions associated with wetlands of different types. Natural wetlands were found to have longer periods of soil saturation and reducing conditions conducive to denitrification compared to the other wetland types studied. Because natural wetlands are typically located in groundwater recharge areas along watershed divides, nitrogen (N) from nearby agriculture was not intercepted. However, these wetlands likely improve water quality in adjacent streams via dilution. Soil and geochemical conditions conducive to denitrification were also present in restored wetlands and prior-converted croplands, and substantial losses of agricultural NO3 were observed in groundwater flowing through these wetland sediments. However, delivery of NO3 from agricultural areas through groundwater to these wetlands resulting in opportunities for

  14. Nitrate and phosphate removal from agricultural subsurface drainage using laboratory woodchip bioreactors and recycled steel byproduct filters.

    PubMed

    Hua, Guanghui; Salo, Morgan W; Schmit, Christopher G; Hay, Christopher H

    2016-10-01

    Woodchip bioreactors have been increasingly used as an edge-of-field treatment technology to reduce the nitrate loadings to surface waters from agricultural subsurface drainage. Recent studies have shown that subsurface drainage can also contribute substantially to the loss of phosphate from agricultural soils. The objective of this study was to investigate nitrate and phosphate removal in subsurface drainage using laboratory woodchip bioreactors and recycled steel byproduct filters. The woodchip bioreactor demonstrated average nitrate removal efficiencies of 53.5-100% and removal rates of 10.1-21.6 g N/m(3)/d for an influent concentration of 20 mg N/L and hydraulic retention times (HRTs) of 6-24 h. When the influent nitrate concentration increased to 50 mg N/L, the bioreactor nitrate removal efficiency and rate averaged 75% and 18.9 g N/m(3)/d at an HRT of 24 h. Nitrate removal by the woodchips followed zero-order kinetics with rate constants of 1.42-1.80 mg N/L/h when nitrate was non-limiting. The steel byproduct filter effectively removed phosphate in the bioreactor effluent and the total phosphate adsorption capacity was 3.70 mg P/g under continuous flow conditions. Nitrite accumulation occurred in the woodchip bioreactor and the effluent nitrite concentrations increased with decreasing HRTs and increasing influent nitrate concentrations. The steel byproduct filter efficiently reduced the level of nitrite in the bioreactor effluent. Overall, the results of this study suggest that woodchip denitrification followed by steel byproduct filtration is an effective treatment technology for nitrate and phosphate removal in subsurface drainage. PMID:27344249

  15. Nitrate and phosphate removal from agricultural subsurface drainage using laboratory woodchip bioreactors and recycled steel byproduct filters.

    PubMed

    Hua, Guanghui; Salo, Morgan W; Schmit, Christopher G; Hay, Christopher H

    2016-10-01

    Woodchip bioreactors have been increasingly used as an edge-of-field treatment technology to reduce the nitrate loadings to surface waters from agricultural subsurface drainage. Recent studies have shown that subsurface drainage can also contribute substantially to the loss of phosphate from agricultural soils. The objective of this study was to investigate nitrate and phosphate removal in subsurface drainage using laboratory woodchip bioreactors and recycled steel byproduct filters. The woodchip bioreactor demonstrated average nitrate removal efficiencies of 53.5-100% and removal rates of 10.1-21.6 g N/m(3)/d for an influent concentration of 20 mg N/L and hydraulic retention times (HRTs) of 6-24 h. When the influent nitrate concentration increased to 50 mg N/L, the bioreactor nitrate removal efficiency and rate averaged 75% and 18.9 g N/m(3)/d at an HRT of 24 h. Nitrate removal by the woodchips followed zero-order kinetics with rate constants of 1.42-1.80 mg N/L/h when nitrate was non-limiting. The steel byproduct filter effectively removed phosphate in the bioreactor effluent and the total phosphate adsorption capacity was 3.70 mg P/g under continuous flow conditions. Nitrite accumulation occurred in the woodchip bioreactor and the effluent nitrite concentrations increased with decreasing HRTs and increasing influent nitrate concentrations. The steel byproduct filter efficiently reduced the level of nitrite in the bioreactor effluent. Overall, the results of this study suggest that woodchip denitrification followed by steel byproduct filtration is an effective treatment technology for nitrate and phosphate removal in subsurface drainage.

  16. Trend reversal of nitrate in Danish groundwater--a reflection of agricultural practices and nitrogen surpluses since 1950.

    PubMed

    Hansen, Birgitte; Thorling, Laerke; Dalgaard, Tommy; Erlandsen, Mogens

    2011-01-01

    This paper assesses the long-term development in the oxic groundwater nitrate concentration and nitrogen (N) loss due to intensive farming in Denmark. First, up to 20-year time-series from the national groundwater monitoring network enable a statistically systematic analysis of distribution, trends, and trend reversals in the groundwater nitrate concentration. Second, knowledge about the N surplus in Danish agriculture since 1950 is used as an indicator of the potential loss of N. Third, groundwater recharge CFC (chlorofluorocarbon) age determination allows linking of the first two data sets. The development in the nitrate concentration of oxic groundwater clearly mirrors the development in the national agricultural N surplus, and a corresponding trend reversal is found in groundwater. Regulation and technical improvements in the intensive farming in Denmark have succeeded in decreasing the N surplus by 40% since the mid 1980s, while at the same time maintaining crop yields and increasing the animal production of especially pigs. Trend analyses prove that the youngest (0-15 years old) oxic groundwater shows more pronounced significant downward nitrate trends (44%) than the oldest (25-50 years old) oxic groundwater (9%). This amounts to clear evidence of the effect of reduced nitrate leaching on groundwater nitrate concentrations in Denmark. PMID:21138289

  17. Interacting effects of vegetation and hydrogeomorphic complexity on nitrate in agricultural waterways

    NASA Astrophysics Data System (ADS)

    Webster, A.; Cadenasso, M. L.

    2015-12-01

    Intensive cultivation in the California Central Valley has resulted in the loss of ~95% of riparian habitat. In addition, small streams have been replaced by denuded agricultural waterways to convey irrigation drainage high in nitrate (NO3). A variety of strategies are being used to increase riparian vegetation along agricultural waterways, but many of the ecological functions of these novel habitat features are unknown. An extensive study was conducted in summer 2014 to investigate which riparian ecosystem features are associated with variable NO3 levels in waterways draining irrigated cropland. Eighty sites were selected to represent a wide range of riparian vegetation, hydrogeomorphic features, and agricultural contexts. Sites were visited three times to correspond to the early, mid, and late irrigation season. At each visit, water samples were taken 300m apart and analyzed for turbidity, pH, temperature, and NO3. To characterized hydrogeomorphic complexity, the frequency of features associated with transient storage and increased retention time were quantified. Vegetation cover and structure on banks, foreshores, and in channels was also measured. Using a generalized linear model, we tested for the interaction of upstream [NO3-N] with vegetation and hydrogeomorphic variables to predict downstream [NO3-N], the dependent variable. As expected, upstream [NO3-N] strongly predicted downstream [NO3-N] and no features directly predicted downstream [NO3-N]. The frequency of hydrogeomorphic features, however, interacted with upstream [NO3-N] to predict downstream [NO3-N], indicating an effect of hydrogeomorphic complexity on NO3 from up to downstream. Vegetation factors did not interact with upstream [NO3-N], but woody vegetation cover was positively correlated with the frequency of hydrogeomorphic features. These findings support the use of woody riparian vegetation to increase NO3 retention in agricultural waterways, via an indirect association with hydrogeomorphic

  18. Linking Groundwater Nitrate-N Concentrations to Management and Hydrological Changes in two Agricultural Catchments

    NASA Astrophysics Data System (ADS)

    Mellander, Per-Erik; Melland, Alice R.; Jordan, Philip; Murphy, Paul N. C.; Shortle, Ger

    2013-04-01

    In order to minimize Nitrogen (N) transfer from groundwater to surface water in agricultural river catchments it is useful to understand how those transfer pathways may vary over time and space, and thus in their connection to nutrient sources and potential effects of temporal changes in water recharge and land management. In this paper we investigate the links between N sources, groundwater and surface water, as well as the implication of spatiotemporal variability for mitigation measures. We present three years of N concentrations in stream water (sub-hourly) and in groundwater (monthly) of different strata in four hillslopes in two ca 10 km2 Irish agricultural catchments with permeable soils. One catchment with arable land overlying slate bedrock and the other with intensively managed grassland on sandstone. Both catchments were dominated by delayed nutrient transfer pathways via groundwater. Relatively high concentrations of N were found in the groundwater of both catchments, attributed to leaching of surplus soil nitrate-N. The Grassland/sandstone catchment had locally higher nitrate-N concentrations in the groundwater with more spatiotemporal variability than in the groundwater of the Arable/Slate catchment. The N concentrations in the stream water of the Arable/Slate catchment were more directly reflected by groundwater conditions. In one hillslope the effects of pasture reseeding were observed by locally elevated N concentrations in the groundwater with a delay of ca five months. This was not reflected in the surface water despite groundwater dominating the contribution to stream water. In another hillslope N was naturally buffered in the near-stream zone, but this zone was bypassed with high nitrate-N content water from the uplands via tile-drains. The apparent spatiotemporal variability in N concentration highlights the need for insight into these differences when interpreting groundwater quality data from a limited number of sampling points and occasions

  19. [Nitrates in cardiology: current role and areas of uncertainty].

    PubMed

    Bellisarii, Francesco Iachini; Muscente, Francesca; Radico, Francesco; Appignani, Marianna; De Caterina, Raffaele

    2011-01-01

    Nitrates have been commonly used in the therapy of cardiovascular disease for more than 150 years. In spite of this longevity and the popularity of their use, it appears somewhat paradoxical that their use is not consistent among cardiologists, both as to their indications and as to their mode of administration. In part this results from their contradictory pharmacodynamics: when given acutely, their effectiveness is indisputable; however, their long-term efficacy is substantially limited by the development of tolerance and the induction of endothelial dysfunction, which may have negative prognostic implications. This review, reporting the most recent biochemical and pathophysiological acquisitions, re-examines the role of nitrates in cardiovascular medicine, reporting, comparing and commenting international guidelines.

  20. Nitrate contamination of groundwater in two areas of the Cameroon Volcanic Line (Banana Plain and Mount Cameroon area)

    NASA Astrophysics Data System (ADS)

    Ako, Andrew Ako; Eyong, Gloria Eneke Takem; Shimada, Jun; Koike, Katsuaki; Hosono, Takahiro; Ichiyanagi, Kimpei; Richard, Akoachere; Tandia, Beatrice Ketchemen; Nkeng, George Elambo; Roger, Ntankouo Njila

    2014-06-01

    Water containing high concentrations of nitrate is unfit for human consumption and, if discharging to freshwater or marine habitats, can contribute to algal blooms and eutrophication. The level of nitrate contamination in groundwater of two densely populated, agro-industrial areas of the Cameroon Volcanic Line (CVL) (Banana Plain and Mount Cameroon area) was evaluated. A total of 100 samples from boreholes, open wells and springs (67 from the Banana Plain; 33 from springs only, in the Mount Cameroon area) were collected in April 2009 and January 2010 and analyzed for chemical constituents, including nitrates. The average groundwater nitrate concentrations for the studied areas are: 17.28 mg/l for the Banana Plain and 2.90 mg/l for the Mount Cameroon area. Overall, groundwaters are relatively free from excessive nitrate contamination, with nitrate concentrations in only 6 % of groundwater resources in the Banana Plain exceeding the maximum admissible concentration for drinking water (50 mg/l). Sources of NO3 - in groundwater of this region may be mainly anthropogenic (N-fertilizers, sewerage, animal waste, organic manure, pit latrines, etc.). Multivariate statistical analyses of the hydrochemical data revealed that three factors were responsible for the groundwater chemistry (especially, degree of nitrate contamination): (1) a geogenic factor; (2) nitrate contamination factor; (3) ionic enrichment factor. The impact of anthropogenic activities, especially groundwater nitrate contamination, is more accentuated in the Banana Plain than in the Mount Cameroon area. This study also demonstrates the usefulness of multivariate statistical analysis in groundwater study as a supplementary tool for interpretation of complex hydrochemical data sets.

  1. Quality of ground water in agricultural areas of the San Luis Valley, south-central Colorado

    USGS Publications Warehouse

    Edelmann, Patrick; Buckles, D.R.

    1984-01-01

    The quality of ground water in the principal agricultural areas of the San Luis Valley, south-central Colorado was evaluated using chemical analyses of water collected from 57 wells completed in the unconfined aquifer and from 25 wells completed in the confined aquifer. Ground water in both aquifers generally contains dissolved-solids concentrations of less than 500 milligrams per liter. In most areas, calcium is the principal cation in the ground water. Nitrite plus nitrate concentrations expressed as nitrogen, are generally less than 1 milligram per liter. However, the quality of ground water in certain areas may pose health and agricultural hazards. Water in the unconfined aquifer near Center contains high nitrite plus nitrate as nitrogen concentrations. The highest measured concentration in this area was 33 milligrams per liter. Water containing more than 1 milligram per liter of nitrite as nitrogen, or 10 milligrams per liter nitrate, as nitrogen, poses a potential health hazard for infants and should not be used for drinking. In addition, dissolved-solids concentration in the ground water in some areas is greater than 500 milligrams per liter and, if used for irrigation may reduce crop yields. (USGS)

  2. Dynamics of nitrate and chloride during storm events in agricultural catchments with different subsurface drainage intensity (Indiana, USA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grids of perforated pipe buried beneath many poorly drained agricultural fields in the Midwestern U.S. are believed to “short circuit” pools of nitrate-laden soil water and shallow groundwater directly into streams that eventually discharge to the Mississippi River. Although much is known about the ...

  3. Stoichiometric Determination of Nitrate Fate in Agricultural Ecosystems during Rainfall Events

    PubMed Central

    Wang, Yiyao

    2015-01-01

    Ecologists have found a close relationship between the concentrations of nitrate (NO3-) and dissolved organic carbon (DOC) in ecosystems. However, it is difficult to determine the NO3- fate exactly because of the low coefficient in the constructed relationship. In the present paper, a negative power-function equation (r2 = 0.87) was developed by using 411 NO3- data points and DOC:NO3- ratios from several agricultural ecosystems during different rainfall events. Our analysis of the stoichiometric method reveals several observations. First, the NO3- concentration demonstrated the largest changes when the DOC:NO3- ratio increased from 1 to 10. Second, the biodegradability of DOC was an important factor in controlling the NO3- concentration of agricultural ecosystems. Third, sediment was important not only as a denitrification site, but also as a major source of DOC for the overlying water. Fourth, a high DOC concentration was able to maintain a low NO3- concentration in the groundwater. In conclusion, this new stoichiometric method can be used for the accurate estimation and analysis of NO3- concentrations in ecosystems. PMID:25849210

  4. The role of dissolved organic nitrogen in a nitrate-rich agricultural stream.

    PubMed

    Oviedo-Vargas, Diana; Royer, Todd V

    2015-03-01

    Agricultural activities have heavily altered the nitrogen (N) cycle in stream ecosystems draining croplands, particularly in the midwestern United States. However, our knowledge about dissolved organic N (DON) biogeochemistry in agricultural ecosystems is limited. From January 2011 to June 2012, we investigated DON dynamics in an agricultural headwater stream in the midwestern United States. We quantified the contribution of DON to the total dissolved N (TDN) pool and examined the role of DON as a source of N for microbial metabolism. For this we measured N-acquiring enzyme activities (aminopeptidases) and whole-stream DON uptake through short-term releases of amino acids. To investigate potential coupling between the N and C cycles occurring via simultaneous uptake of these two elements during assimilation of amino acids, seven of the short-term releases were performed concurrently with acetate. We found minimal contribution of DON to the TDN pool in this stream as a result of high concentrations of nitrate. Acetate uptake suggested that C was a limiting factor for microbial metabolism in this stream. In contrast, we were not able to detect amino acid uptake during any of the 13 short-term releases we conducted, likely as a result of high availability of dissolved inorganic N. Aminopeptidase (AMP) activity did not reflect N demand. Large spatial variability in AMP was observed within and among sites, possibly as result of physicochemical characteristics of the sediments. In contrast to other human-dominated streams, DON appeared to play a minor role in microbial metabolic processes and contributed minimally to the N pool of the study stream. PMID:26023984

  5. Distribution of nitrate in the unsaturated zone, Highland-East Highlands area, San Bernardino County, California

    USGS Publications Warehouse

    Klein, John M.; Bradford, Wesley L.

    1980-01-01

    Nitrogen in the unsaturated soil zone in the Highland-East Highlands area of San Bernardino County, Calif., has been suspected as the source of nitrate in water from wells. Plans to recharge the local aquifers with imported surface water would raise the water table and intercept that nitrogen. This study was made to describe the distribution of inorganic nitrogen and other chemical constituents and nitrogen-using bacteria in the unsaturated zone, to relate nitrogen occurrences, in a general way, to present and historical land use, and to attempt to predict nitrogen concentrations in ground water after recharge. Some generalized correlations between nitrogen occurrence and land use were observed. In 11 of 13 test holes, the maximum nitrate-nitrogen (NO3--N) concentrations occurred within 10 feet of the surface, suggesting that the major source of nitrogen is from the surface at these sites. Test holes were ranked according to maximum NO3--N in the top 10 feet, total NO3--N in the top 10 feet, and total NO3--N in the top 40 feet. In all three rankings, the top seven test holes were the same--five in or near present or historical agricultural areas (primarily citrus groves), one in a feedlot, and one adjacent to an abandoned sewage-treatment plant. Two test holes in historically uninhabited areas ranked lowest. The control test hole in an uninhabited area ranked high in geometric mean of ammonium-nitrogen concentration (NH4+-N), suggesting that present in freshly weathered granite. The geometric means of NH4+-N concentrations in six of eight citrus-related test holes were significantly lower than in the control hole, suggesting that irrigation in citrus groves may have created conditions favoring nitrification of the primary NH4+-N. Rank correlation analyses between various measurements in test holes showed that high NO3--N concentrations tend to occur with high specific conductance and chloride concentrations in soil extracts. If recharge is carried out as planned

  6. Identification of nitrate long term trends in Loire-Brittany river district (France) in connection with hydrogeological contexts, agricultural practices and water table level variations

    NASA Astrophysics Data System (ADS)

    Lopez, B.; Baran, N.; Bourgine, B.; Ratheau, D.

    2009-04-01

    follow a significant downward trend period (Orléans). In the nineties, a transition period may have occurred with a higher proportion of upward than downward trends (82 % against 7 % respectively) for the 1980-1990 period and a lower proportion of upward than downward trends for the 2000-2007 period (37 % against 51 % respectively). Combined with the analyse of the current groundwater nitrate concentrations, the KR test reveals zones where trends in nitrate concentrations have been significantly raising with high nitrate current mean values (> 50 mg NO3 L-1). On the other hand, some zones show a significant regional downward trend since 1995 and low current nitrate concentrations (< 20 mg NO3 L-1). Causes of trend reversals cannot be determined by the MK and KR statistical trend analyses, but the cross analyse of nitrate and water table level time-series gives a hint of a positive correlation between these two variables. Evolution of nitrate concentrations in superficial aquifers may thus depend on a combined effect of changes in both agricultural practices and evolution of water table levels linked with climatic context. References Aguilar J.B., Orban P., Dassargues A., Brouyère S., (2007) - Identification of groundwater quality trends in a chalk aquifer threatened by intensive agriculture in Belgium. Hydrogeology journal 15: 1615-1627. Broers H.P., van der Grift B., (2004) - Regional monitoring of temporal changes in groundwater quality. Journal of hydrology 296: 192-220. Frans L.M., Helsel D.R. (2005) - Evaluating regional trends in ground water nitrate concentrations of the Columbia Basin Ground Water management Area, Washington. U.S. Geological Survey Scientific Investigations Report 2005-5078, 7p. Stuart M.E., Chilton P.J., Kiniiburgh D.G., Cooper D.M., (2007) - Screening for long-term trends in groundwater nitrate monitoring data. Quaterly Journal of Engineering Geology and Hydrogeology, 40: 361-376. Funding The study was funded by the Loire-Brittany River Basin

  7. Predicting groundwater nitrate concentrations in a region of mixed agricultural land use: a comparison of three approaches.

    PubMed

    McLay, C D; Dragten, R; Sparling, G; Selvarajah, N

    2001-01-01

    We investigated whether nitrate-N (NO3(-)-N) concentrations of shallow groundwater (< 30 m from the land surface) in a region of intensive agriculture could be predicted on the basis of land use information, topsoil properties that affect the ability of topsoil to generate nitrate at a site, or the 'leaching risk' at different sites. Groundwater NO3(-)-N concentrations were collected biannually for 3 years at 88 sites within the Waikato Region of New Zealand. The land use was classed as either the predominant land use of the farm where the well or bore was located, or the dominant land use within a 500 m radius of the well or bore. Topsoil properties that affect the ability of soil to generate nitrate were also measured at all the sites, and a leaching risk assessment model 'DRASTIC' was used to assess the risk of NO3(-)-N leaching to groundwater at each site. The concentration of NO3(-)-N in shallow groundwater in the Waikato Region varied considerably, both temporally and spatially. Nine percent of sites surveyed had groundwater NO3(-)-N concentrations exceeding maximum allowable concentrations of 11.3 ppm recommended by the World Health Organisation for potable drinking water which is accepted as a public health standard in New Zealand. Over half (56%) of the sites had concentrations that exceeded 3 ppm, indicating effects of human activities (commonly referred to as a human activity value). Very few trends in NO3(-)-N concentration that could be attributed to land use were identified, although market garden sites had higher concentrations of NO3(-)-N in underlying groundwater than drystock/sheep sites when the land use within 500 m radius of a sampling site was used to define the land use. There was also some evidence that within a district, NO3(-)-N concentrations in groundwater increased as the proportion of area used for dairy farming increased. Compared to pastoral land, market gardens had lower total C and N, potentially mineralisable N and denitrifying

  8. Predicting groundwater nitrate concentrations in a region of mixed agricultural land use: a comparison of three approaches.

    PubMed

    McLay, C D; Dragten, R; Sparling, G; Selvarajah, N

    2001-01-01

    We investigated whether nitrate-N (NO3(-)-N) concentrations of shallow groundwater (< 30 m from the land surface) in a region of intensive agriculture could be predicted on the basis of land use information, topsoil properties that affect the ability of topsoil to generate nitrate at a site, or the 'leaching risk' at different sites. Groundwater NO3(-)-N concentrations were collected biannually for 3 years at 88 sites within the Waikato Region of New Zealand. The land use was classed as either the predominant land use of the farm where the well or bore was located, or the dominant land use within a 500 m radius of the well or bore. Topsoil properties that affect the ability of soil to generate nitrate were also measured at all the sites, and a leaching risk assessment model 'DRASTIC' was used to assess the risk of NO3(-)-N leaching to groundwater at each site. The concentration of NO3(-)-N in shallow groundwater in the Waikato Region varied considerably, both temporally and spatially. Nine percent of sites surveyed had groundwater NO3(-)-N concentrations exceeding maximum allowable concentrations of 11.3 ppm recommended by the World Health Organisation for potable drinking water which is accepted as a public health standard in New Zealand. Over half (56%) of the sites had concentrations that exceeded 3 ppm, indicating effects of human activities (commonly referred to as a human activity value). Very few trends in NO3(-)-N concentration that could be attributed to land use were identified, although market garden sites had higher concentrations of NO3(-)-N in underlying groundwater than drystock/sheep sites when the land use within 500 m radius of a sampling site was used to define the land use. There was also some evidence that within a district, NO3(-)-N concentrations in groundwater increased as the proportion of area used for dairy farming increased. Compared to pastoral land, market gardens had lower total C and N, potentially mineralisable N and denitrifying

  9. Nitrate source identification in groundwater of multiple land-use areas by combining isotopes and multivariate statistical analysis: A case study of Asopos basin (Central Greece).

    PubMed

    Matiatos, Ioannis

    2016-01-15

    Nitrate (NO3) is one of the most common contaminants in aquatic environments and groundwater. Nitrate concentrations and environmental isotope data (δ(15)N-NO3 and δ(18)O-NO3) from groundwater of Asopos basin, which has different land-use types, i.e., a large number of industries (e.g., textile, metal processing, food, fertilizers, paint), urban and agricultural areas and livestock breeding facilities, were analyzed to identify the nitrate sources of water contamination and N-biogeochemical transformations. A Bayesian isotope mixing model (SIAR) and multivariate statistical analysis of hydrochemical data were used to estimate the proportional contribution of different NO3 sources and to identify the dominant factors controlling the nitrate content of the groundwater in the region. The comparison of SIAR and Principal Component Analysis showed that wastes originating from urban and industrial zones of the basin are mainly responsible for nitrate contamination of groundwater in these areas. Agricultural fertilizers and manure likely contribute to groundwater contamination away from urban fabric and industrial land-use areas. Soil contribution to nitrate contamination due to organic matter is higher in the south-western part of the area far from the industries and the urban settlements. The present study aims to highlight the use of environmental isotopes combined with multivariate statistical analysis in locating sources of nitrate contamination in groundwater leading to a more effective planning of environmental measures and remediation strategies in river basins and water bodies as defined by the European Water Frame Directive (Directive 2000/60/EC). PMID:26437351

  10. Nitrate source identification in groundwater of multiple land-use areas by combining isotopes and multivariate statistical analysis: A case study of Asopos basin (Central Greece).

    PubMed

    Matiatos, Ioannis

    2016-01-15

    Nitrate (NO3) is one of the most common contaminants in aquatic environments and groundwater. Nitrate concentrations and environmental isotope data (δ(15)N-NO3 and δ(18)O-NO3) from groundwater of Asopos basin, which has different land-use types, i.e., a large number of industries (e.g., textile, metal processing, food, fertilizers, paint), urban and agricultural areas and livestock breeding facilities, were analyzed to identify the nitrate sources of water contamination and N-biogeochemical transformations. A Bayesian isotope mixing model (SIAR) and multivariate statistical analysis of hydrochemical data were used to estimate the proportional contribution of different NO3 sources and to identify the dominant factors controlling the nitrate content of the groundwater in the region. The comparison of SIAR and Principal Component Analysis showed that wastes originating from urban and industrial zones of the basin are mainly responsible for nitrate contamination of groundwater in these areas. Agricultural fertilizers and manure likely contribute to groundwater contamination away from urban fabric and industrial land-use areas. Soil contribution to nitrate contamination due to organic matter is higher in the south-western part of the area far from the industries and the urban settlements. The present study aims to highlight the use of environmental isotopes combined with multivariate statistical analysis in locating sources of nitrate contamination in groundwater leading to a more effective planning of environmental measures and remediation strategies in river basins and water bodies as defined by the European Water Frame Directive (Directive 2000/60/EC).

  11. 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.

  12. Water-quality assessment of the Delmarva Peninsula, Delaware, Maryland, and Virginia; effects of agricultural activities on, and distribution of, nitrate and other inorganic constituents in the surficial aquifer

    USGS Publications Warehouse

    Hamilton, P.A.; Denver, J.M.; Phillips, P.J.; Shedlock, R.J.

    1993-01-01

    Agricultural applications of inorganic fertilizers and manure have changed the natural chemical com- position of water in the surficial aquifer through- out the Delmarva Peninsula. Nitrate, derived from nitrification of ammonia in inorganic fertilizers and manure, is the dominant anion in agricultural areas. Concentrations of nitrate in 185 water samples collected in agricultural areas ranged from 0.4 to 48 mg/L as nitrogen, with a median concen- tration of 8.2 mg/L as nitrogen. Nitrate concen- trations exceeded the U.S. Environmental Protection Agency's maximum contaminant level for drinking water of 10 mg/L as nitrogen in about 33% of the 185 water samples. Groundwater affected by agricultural activities contains significantly higher concentrations of dissolved constituents than does natural groundwater. Concentrations of calcium and magnesium are higher because of liming of soils, and concentrations of potassium and chloride are higher because of applications of potash, a supple- ment to the nitrogen-based fertilizers. Alkalinity concentrations commonly are decreased because the bicarbonate ion is consumed in buffering reactions with acid that is produced during nitrification. Effects of agricultural activities on groundwater quality are not limited to the near-surface parts of the aquifer underlying farm fields. Elevated concentrations are common in aerobic water at or near the base of the aquifer, 80 to 100 ft below land surface. The median concentration of nitrate in water beneath agricultural areas collected from 24 wells deeper than 80 ft below land surface was 8.5 mg/L as nitrogen, and concentrations in 9 of these water samples exceeded the maximum contaminant level. Regional variations in concentrations of nitrate and other agriculture related constituents in the surficial aquifer in the Delmarva Peninsula depend on a number of factors that include geomorphology, geology, soils, land use, and groundwater-flow patterns. (USGS)

  13. Factors affecting leaching in agricultural areas and an assessment of agricultural chemicals in the ground water of Kansas

    USGS Publications Warehouse

    Perry, C.A.; Robbins, F.V.; Barnes, P.L.

    1988-01-01

    As assessment of hydrologic factors and agricultural practices that may affect the leaching of agricultural chemicals to groundwater was conducted to evaluate the extent and severity of chemical contamination of groundwater resources in Kansas. The climate of a particular area determines the length of the growing season and the availability of water, at the surface and in the ground, for the growth of plants. Climate, together with surficial geology, soil, and principal aquifers, determines the types of crops to be planted,types of tillage, conservation and irrigation practices, and affects the quantity and method of application of agricultural chemicals. Examination of groundwater nitrate-nitrogen data collected from 766 wells throughout Kansas during 1976-81 indicated that 13 of 14 geohydrologic regions had wells producing samples that exceeded the 10-mg/L drinking water standard determined by the U.S. Environmental Protection Agency. One or more herbicides were detected in water samples from 11 of 56 wells during 1985-86 located in areas susceptible to agricultural leaching. Atrazine was the most common herbicide that was detected; it was detected in water at 9 of 11 wells. Cyanazine was detected in water at three wells; metolachlor at two wells; and metribuzin, alachlor, simazine, and propazine were detected at one well each. (USGS)

  14. 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

  15. Relations of nonpoint-source nitrate and atrazine concentrations in the High Plains aquifer to selected explanatory variables in six Nebraska study areas

    USGS Publications Warehouse

    Druliner, A.D.; Chen, H.H.; McGrath, T.S.

    1996-01-01

    Statistical techniques were used to relate nonpoint-source ground-water contamination by nitrate and atrazine to a variety of explanatory variables for six study areas in Nebraska. Water samples were collected from 268 wells in 12 counties from 1984 through 1987 and were analyzed for nitrate concentrations; water samples from 210 of the wells were analyzed for atrazine. A number of hydrochemical, climatic, hydrologic, soil, and land-use explanatory variables, which were believed to affect the contamination of ground water by agricultural chemicals, were identified and quantified for each of the 268 wells. Multiple regression methods were used to determine which explanatory variables were statistically related to ground-water concentrations of nitrate and atrazine. Regression models predicting nitrate and atrazine concentrations were produced that explained from about 50 to 68 percent of the variation in the dependent variables. Geographic- information-system methods were used to produce maps predicting nitrate and atrazine concentrations in ground water for one study area using selected regression and logistic models. The results of this study indicate that multiple regression techniques coupled with geographic information systems can be an effective means of identifying areas of potential ground-water contamination by nitrate and atrazine.

  16. Nitrate sinks and sources as controls of spatio-temporal water quality dynamics in an agricultural headwater catchment

    NASA Astrophysics Data System (ADS)

    Schuetz, Tobias; Gascuel-Odoux, Chantal; Durand, Patrick; Weiler, Markus

    2016-02-01

    Several controls are known to affect water quality of stream networks during flow recession periods, such as solute leaching processes, surface water-groundwater interactions as well as biogeochemical in-stream turnover processes. Throughout the stream network, combinations of specific water and solute export rates and local in-stream conditions overlay the biogeochemical signals from upstream sections. Therefore, upstream sections can be considered functional units which could be distinguished and ordered regarding their relative contribution to nutrient dynamics at the catchment outlet. Based on snapshot sampling of flow and nitrate concentrations along the stream in an agricultural headwater during the summer flow recession period, we determined spatial and temporal patterns of water quality for the whole stream. A data-driven, in-stream-mixing-and-removal model was developed and applied for analysing the spatio-temporal in-stream retention processes and their effect on the spatio-temporal fluxes of nitrate from subcatchments. Thereby, we have been able to distinguish quantitatively between nitrate sinks, sources per stream reaches, and subcatchments, and thus we could disentangle the overlay of nitrate sink and source signals. For nitrate sources, we determined their permanent and temporal impact on stream water quality and for nitrate sinks, we found increasing nitrate removal efficiencies from upstream to downstream. Our results highlight the importance of distinct nitrate source locations within the watershed for in-stream concentrations and in-stream removal processes, respectively. Thus, our findings contribute to the development of a more dynamic perception of water quality in streams and rivers concerning ecological and sustainable water resource management.

  17. Estimating the probability of elevated nitrate (NO2+NO3-N) concentrations in ground water in the Columbia Basin Ground Water Management Area, Washington

    USGS Publications Warehouse

    Frans, Lonna M.

    2000-01-01

    Logistic regression was used to relate anthropogenic (man-made) and natural factors to the occurrence of elevated concentrations of nitrite plus nitrate as nitrogen in ground water in the Columbia Basin Ground Water Management Area, eastern Washington. Variables that were analyzed included well depth, depth of well casing, ground-water recharge rates, presence of canals, fertilizer application amounts, soils, surficial geology, and land-use types. The variables that best explain the occurrence of nitrate concentrations above 3 milligrams per liter in wells were the amount of fertilizer applied annually within a 2-kilometer radius of a well and the depth of the well casing; the variables that best explain the occurrence of nitrate above 10 milligrams per liter included the amount of fertilizer applied annually within a 3-kilometer radius of a well, the depth of the well casing, and the mean soil hydrologic group, which is a measure of soil infiltration rate. Based on the relations between these variables and elevated nitrate concentrations, models were developed using logistic regression that predict the probability that ground water will exceed a nitrate concentration of either 3 milligrams per liter or 10 milligrams per liter. Maps were produced that illustrate the predicted probability that ground-water nitrate concentrations will exceed 3 milligrams per liter or 10 milligrams per liter for wells cased to 78 feet below land surface (median casing depth) and the predicted depth to which wells would need to be cased in order to have an 80-percent probability of drawing water with a nitrate concentration below either 3 milligrams per liter or 10 milligrams per liter. Maps showing the predicted probability for the occurrence of elevated nitrate concentrations indicate that the irrigated agricultural regions are most at risk. The predicted depths to which wells need to be cased in order to have an 80-percent chance of obtaining low nitrate ground water exceed 600 feet

  18. Recycling soil nitrate nitrogen by amending agricultural lands with oily food waste.

    PubMed

    Rashid, M T; Voroney, R P

    2003-01-01

    With current agricultural practices the amounts of fertilizer N applied are frequently more than the amounts removed by the crop. Excessive N application may result in short-term accumulation of nitrate nitrogen (NO3-N) in soil, which can easily be leached from the root zone and into the ground water. A management practice suggested for conserving accumulated NO3-N is the application of oily food waste (FOG; fat + oil + greases) to agricultural soils. A two-year field study (1995-1996 and 1996-1997) was conducted at Elora Research Center (43 degrees 38' N, 80 degrees W; 346 m above mean sea level), University of Guelph, Ontario, Canada to determine the effect of FOG application in fall and spring on soil NO3-N contents and apparent N immobilization-mineralization of soil N in the 0- to 60-cm soil layer. The experiment was planned under a randomized complete block design with four replications. An unamended control and a reference treatment [winter wheat (Triticum aestivum L.) cover crop] were included in the experiment to compare the effects of fall and spring treatment of oily food waste on soil NO3-N contents and apparent N immobilization-mineralization. Oily food waste application at 10 Mg ha(-1) in the fall decreased soil NO3-N by immobilization and conserved 47 to 56 kg NO3-N ha(-1), which would otherwise be subject to leaching. Nitrogen immobilized due to FOG application in the fall was subsequently remineralized by the time of fertilizer N sidedress, whereas no net mineralization was observed in spring-amended plots at the same time.

  19. The fate of fertilizer nitrogen in a high nitrate accumulated agricultural soil.

    PubMed

    Quan, Zhi; Huang, Bin; Lu, Caiyan; Shi, Yi; Chen, Xin; Zhang, Haiyang; Fang, Yunting

    2016-02-12

    Well-acclimatized nitrifiers in high-nitrate agricultural soils can quickly nitrify NH4(+) into NO3(-) subject to leaching and denitrifying loss. A 120-day incubation experiment was conducted using a greenhouse soil to explore the fates of applied fertilizer N entering into seven soil N pools and to examine if green manure (as ryegrass) co-application can increase immobilization of the applied N into relatively stable N pools and thereby reduce NO3(-) accumulation and loss. We found that 87-92% of the applied (15)N-labelled NH4(+) was rapidly recovered as NO3(-) since day 3 and only 2-4% as microbial biomass and soil organic matter (SOM), while ryegrass co-application significantly decreased its recovery as NO3(-) but enhanced its recovery as SOM (17%) at the end of incubation. The trade-off relationship between (15)N recoveries in microbial biomass and SOM indicated that ryegrass co-application stabilized newly immobilized N via initial microbial uptake and later breakdown. Nevertheless, ryegrass application didn't decrease soil total NO3(-) accumulation due to its own decay. Our results suggest that green manure co-application can increase immobilization of applied N into stable organic N via microbial turnover, but the quantity and quality of green manure should be well considered to reduce N release from itself.

  20. The fate of fertilizer nitrogen in a high nitrate accumulated agricultural soil

    PubMed Central

    Quan, Zhi; Huang, Bin; Lu, Caiyan; Shi, Yi; Chen, Xin; Zhang, Haiyang; Fang, Yunting

    2016-01-01

    Well-acclimatized nitrifiers in high-nitrate agricultural soils can quickly nitrify NH4+ into NO3− subject to leaching and denitrifying loss. A 120-day incubation experiment was conducted using a greenhouse soil to explore the fates of applied fertilizer N entering into seven soil N pools and to examine if green manure (as ryegrass) co-application can increase immobilization of the applied N into relatively stable N pools and thereby reduce NO3− accumulation and loss. We found that 87–92% of the applied 15N-labelled NH4+ was rapidly recovered as NO3− since day 3 and only 2–4% as microbial biomass and soil organic matter (SOM), while ryegrass co-application significantly decreased its recovery as NO3− but enhanced its recovery as SOM (17%) at the end of incubation. The trade-off relationship between 15N recoveries in microbial biomass and SOM indicated that ryegrass co-application stabilized newly immobilized N via initial microbial uptake and later breakdown. Nevertheless, ryegrass application didn’t decrease soil total NO3− accumulation due to its own decay. Our results suggest that green manure co-application can increase immobilization of applied N into stable organic N via microbial turnover, but the quantity and quality of green manure should be well considered to reduce N release from itself. PMID:26868028

  1. [Spatial and temporal variability of nitrate contaminant in groundwater in Jinfo Mt. area, Chongqing, China].

    PubMed

    Wu, Kun-Yu; Wang, Peng; Shen, Li-Cheng; Xiao, Qiong

    2011-11-01

    The geochemical background of nitrate in groundwater in Jinfo Mt. area was determined, and spatial and temporal variability of nitrate contaminant was analyzed using geochemical, statistical and GIS methods. Twenty-three samples were collected from groundwater discharge points in the study area during 1976-1977, 2004-2006 and 2009, and mass concentration of nitrate in groundwater was tested. The results showed that the geochemical background of nitrate in groundwater in study area was in the range of 0.72-2. 00 mg x L(-1), and the threshold of anomaly was 3.20 mg x L(-1). During 2004-2006 and 2009, the average values of nitrate concentration in groundwater in Jinfo Mt. natural reserve were 2.08, 2.67, 2.59 and 3.92 mg x L(-1); and were 39.08, 25.46, 17.99 and 13.73 mg x L(-1) in the groundwater out of the reserve; the average over-limit rates (standard limit NO3(-) -N < or = 10mg x L(-1)) were 451.64%, 478.61%, 331.85% and 145.67%; the maximum over-limit rates were 1 475.81%, 1 080.39%, 538.20% and 361.78%. Results of interpolation showed that the high value centers of nitrate concentration in groundwater in study area were changing over time, but districts with low nitrate concentration in groundwater in study area were distributed along Jinfo Mt. natural reserve. The application of environmental policy measures and industrial restructuring implemented were reasonable and successful, which had a positive effect to environmental protection.

  2. 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

  3. Are Streams in Agricultural and Urban Areas Contaminated by Pesticides?

    USGS Publications Warehouse

    Kimbrough, R.A.

    1995-01-01

    To answer this question, a study of pesticides in streams in a small agricultural area and a small urban area in Colorado was conducted in 1993 by the U.S. Geological Survey (USGS) as part of the National Water-Quality Assessment (NAWQA) program. The results indicate that pesticides are present in streams, and both agricultural and urban areas are probable sources of the contamination. In the agricultural area, 30 pesticides were detected and in the urban area, 26 pesticides were detected at least once during the thirteen month study. In the agricultural area, the herbicides alachlor (two samples) and cyanazine (four samples) and the insecticide diazinon (one sample) were the only pesticides that exceeded the U.S. Environmental Protection Agency's maximum contaminant levels (MCLs) or health advisory levels (HALs) for drinking water. No pesticides exceeded MCLs or HALs in the urban area.

  4. Whole-stream response to nitrate loading in three streams draining agricultural landscapes

    USGS Publications Warehouse

    Duff, J.H.; Tesoriero, A.J.; Richardson, W.B.; Strauss, E.A.; Munn, M.D.

    2008-01-01

    Physical, chemical, hydrologic, and biologic factors affecting nitrate (NO3 −) removal were evaluated in three agricultural streams draining orchard/dairy and row crop settings. Using 3-d “snapshots” during biotically active periods, we estimated reach-level NO3 − sources, NO3 − mass balance, in-stream processing (nitrification, denitrification, and NO3 − uptake), and NO3 − retention potential associated with surface water transport and ground water discharge. Ground water contributed 5 to 11% to stream discharge along the study reaches and 8 to 42% of gross NO3 − input. Streambed processes potentially reduced 45 to 75% of ground water NO3 − before discharge to surface water. In all streams, transient storage was of little importance for surface water NO3 − retention. Estimated nitrification (1.6–4.4 mg N m−2 h−1) and unamended denitrification rates (2.0–16.3 mg N m−2 h−1) in sediment slurries were high relative to pristine streams. Denitrification of NO3 − was largely independent of nitrification because both stream and ground water were sources of NO3 − Unamended denitrification rates extrapolated to the reach-scale accounted for <5% of NO3 − exported from the reaches minimally reducing downstream loads. Nitrate retention as a percentage of gross NO3 − inputs was >30% in an organic-poor, autotrophic stream with the lowest denitrification potentials and highest benthic chlorophyll a, photosynthesis/respiration ratio, pH, dissolved oxygen, and diurnal NO3 − variation. Biotic processing potentially removed 75% of ground water NO3 − at this site, suggesting an important role for photosynthetic assimilation of ground water NO3 − relative to subsurface denitrification as water passed directly through benthic diatom beds.

  5. Effects of agricultural practices and vadose zone stratigraphy on nitrate concentration in ground water in Kansas, USA

    USGS Publications Warehouse

    Townsend, M.A.; Sleezer, R.O.; Macko, S.A.; ,

    1996-01-01

    Differences in nitrate-N concentrations in,around water in Kansas can be explained by variations in agricultural practices and vadose-zone stratigraphy. In northwestern Kansas, past use of a local stream for tailwater runoff from irrigation and high fertilizer applications for sugar-beet farming resulted in high nitrate-N concentrations (12-60 mg L-1; in both soil and ground water. Nitrogen isotope values from the soil and ground water range from +4 to +8? which is typical for a fertilizer source. In parts of south-central Kansas, the use of crop rotation and the presence of both continuous fine-textured layers and a reducing ground-water chemistry resulted in ground-water nitrate-N values of 10 mg L-1; in both soil and grounwater. Nitrogen isotope values of +3 to +7? indicate a fertilizer source. Crop rotation decreased nitrate-N values in the shallow ground water (9 m). However, deeper ground water showed increasing nitrate-N concentrations as a result of past farming practices.

  6. Baseflow contribution to nitrate-nitrogen export from a large, agricultural watershed, USA

    USGS Publications Warehouse

    Schilling, K.; Zhang, Y.-K.

    2004-01-01

    Nitrate-nitrogen export from the Raccoon River watershed in west-central Iowa is among the highest in the United State and contributes to impairment of downstream water quality. We examined a rare long-term record of streamflow and nitrate concentration data (1972-2000) to evaluate annual and seasonal patterns of nitrate losses in streamflow and baseflow from the Raccoon River. Combining hydrograph separation with a load estimation program, we estimated that baseflow contributes approximately two-thirds (17.3 kg/ha) of the mean annual nitrate export (26.1 kg/ha). Baseflow transport was greatest in spring and late fall when baseflow contributed more than 80% of the total export. Herein we propose a 'baseflow enrichment ratio' (BER) to describe the relation of baseflow water with baseflow nitrate loads. The long-term ratio of 1.23 for the Raccoon River suggests preferential leaching of nitrate to baseflow. Seasonal patterns of the BER identified the strong link between the baseflow nitrate loads and seasonal crop nitrogen requirements. Study results demonstrate the utility of assessing the baseflow contribution to nitrate loads to identify appropriate control strategies for reducing baseflow delivery of nitrate. ?? 2004 Elsevier B.V. All rights reserved.

  7. Baseflow contribution to nitrate-nitrogen export from a large, agricultural watershed, USA

    NASA Astrophysics Data System (ADS)

    Schilling, Keith; Zhang, You-Kuan

    2004-08-01

    Nitrate-nitrogen export from the Raccoon River watershed in west-central Iowa is among the highest in the United State and contributes to impairment of downstream water quality. We examined a rare long-term record of streamflow and nitrate concentration data (1972-2000) to evaluate annual and seasonal patterns of nitrate losses in streamflow and baseflow from the Raccoon River. Combining hydrograph separation with a load estimation program, we estimated that baseflow contributes approximately two-thirds (17.3 kg/ha) of the mean annual nitrate export (26.1 kg/ha). Baseflow transport was greatest in spring and late fall when baseflow contributed more than 80% of the total export. Herein we propose a 'baseflow enrichment ratio' (BER) to describe the relation of baseflow water with baseflow nitrate loads. The long-term ratio of 1.23 for the Raccoon River suggests preferential leaching of nitrate to baseflow. Seasonal patterns of the BER identified the strong link between the baseflow nitrate loads and seasonal crop nitrogen requirements. Study results demonstrate the utility of assessing the baseflow contribution to nitrate loads to identify appropriate control strategies for reducing baseflow delivery of nitrate.

  8. Nitrate Distribution in Soil Moisture and Groundwater with Intensive Plantation Management on Abandoned Agricultural Land

    SciTech Connect

    Williams, T.M.

    1998-01-01

    Paper outlines nitrate leaching results of loblolly pine and sweet gum that were grown with irrigation, continuous fertilization and insect pest control on a year old abandoned peanut field. Wells and tension lysimeters were used to measure nitrate in soil moisture and groundwater on three replicate transects for two years. Groundwater nitrate concentration beneath the minimum treatment was much higher than the maximum treatment and old field. All three treatments often exceeded the drinking water standard. Forest and lake edge had low levels while the soil moisture nitrate concentrations in the two plantations treatments were much higher than the old field.

  9. Nitrogen fertilization, soil nitrate accumulation, and policy recommendations in several agricultural regions of China.

    PubMed

    Ju, Xiaotang; Liu, Xuejun; Zhang, Fusuo; Roelcke, Marco

    2004-08-01

    Excessive nitrogen (N) fertilization and decreasing N recovery rates by crops have caused dramatic increases in non-point source pollution from agriculture in China. The rate of N fertilization across the country varies widely among regions and crops, depending on the stage of economic development. For example, N application rates in the eastern regions and on cash crops are far higher than in western regions of the country and on cereal crops. Moreover, N application rates in wealthier regions are higher than recommended by the Chinese Academy of Sciences. To successfully achieve environmental protection as well as high crop yields, China must formulate relevant agricultural policies to encourage farmers in economically developed areas to reduce their N fertilization rate while also issuing conventional fertilization recommendations for small-scale farming systems and the expanding cultivation of cash crops. PMID:15387063

  10. Interannual climate variability and spatially heterogeneous improvement of agricultural management impede detection of a decreasing trend in nitrate pollution in an agricultural catchment

    NASA Astrophysics Data System (ADS)

    Fovet, Ophélie; Dupas, Rémi; Durand, Patrick; Gascuel-Odoux, Chantal; Gruau, Gérard; Hamon, Yannick; Petitjean, Patrice

    2016-04-01

    Despite widespread implementation of the nitrate directive in the European Union since the 1990s, the impact on nitrate concentration in rivers is limited (Bouraoui and Grizzetti, 2011). To assess whether this lack of response is due to the long time lags of nitrate transfer or to inadequate programs of measure, long term river and groundwater monitoring data are necessary. This study analyses 15 years of daily nitrate concentration data at the outlet of an intensively farmed catchment in Western France (Kervidy-Naizin, 5 km²) and quarterly nitrate concentration data in the groundwater of two hillslopes equipped with piezometers (Kerroland and Gueriniec) within the same catchment. In this catchment groundwater contribution to annual stream flow is dominant. The objectives of this study were to i) disentangle the influence of interannual climate variability and improvement of agricultural practices (i.e. reduction in N surplus) in the stream chemistry and ii) discuss the reasons for slow catchment recovery from nitrate pollution by comparing trends in groundwater and stream concentrations. Analysis of stream data showed that flow-weighted mean annual concentration at the outlet of the Kervidy-Naizin catchment has decreased by 1.2 mg NO3- l-1 yr-1 from 1999 to 2015. This decrease was slow but significant (p value < 0.01) even though interannual climate variability (i.e. annual cumulated runoff) added noise to the signal: i) deviation in the linear model of nitrate decrease with time was negatively correlated with annual runoff (r = -0.54, p < 0.01) and ii) local minimums in the nitrate time series were coincident with local maximums in the annual runoff. Thus high runoff during wet years led to dilution of the nitrate originating from groundwater, which added variability to the signal of linear decrease in stream concentration. Analysis of groundwater data showed a significant and sharp decrease in nitrate concentration in the Kerroland piezometer transect (4.0 mg

  11. Hydrochemical and multivariate statistical interpretations of spatial controls of nitrate concentrations in a shallow alluvial aquifer around oxbow lakes (Osong area, central Korea).

    PubMed

    Kim, Kyoung-Ho; Yun, Seong-Taek; Choi, Byoung-Young; Chae, Gi-Tak; Joo, Yongsung; Kim, Kangjoo; Kim, Hyoung-Soo

    2009-07-21

    Hydrochemical and multivariate statistical interpretations of 16 physicochemical parameters of 45 groundwater samples from a riverside alluvial aquifer underneath an agricultural area in Osong, central Korea, were performed in this study to understand the spatial controls of nitrate concentrations in terms of biogeochemical processes occurring near oxbow lakes within a fluvial plain. Nitrate concentrations in groundwater showed a large variability from 0.1 to 190.6 mg/L (mean=35.0 mg/L) with significantly lower values near oxbow lakes. The evaluation of hydrochemical data indicated that the groundwater chemistry (especially, degree of nitrate contamination) is mainly controlled by two competing processes: 1) agricultural contamination and 2) redox processes. In addition, results of factorial kriging, consisting of two steps (i.e., co-regionalization and factor analysis), reliably showed a spatial control of the concentrations of nitrate and other redox-sensitive species; in particular, significant denitrification was observed restrictedly near oxbow lakes. The results of this study indicate that sub-oxic conditions in an alluvial groundwater system are developed geologically and geochemically in and near oxbow lakes, which can effectively enhance the natural attenuation of nitrate before the groundwater discharges to nearby streams. This study also demonstrates the usefulness of multivariate statistical analysis in groundwater study as a supplementary tool for interpretation of complex hydrochemical data sets. PMID:19524319

  12. Hydrochemical and multivariate statistical interpretations of spatial controls of nitrate concentrations in a shallow alluvial aquifer around oxbow lakes (Osong area, central Korea)

    NASA Astrophysics Data System (ADS)

    Kim, Kyoung-Ho; Yun, Seong-Taek; Choi, Byoung-Young; Chae, Gi-Tak; Joo, Yongsung; Kim, Kangjoo; Kim, Hyoung-Soo

    2009-07-01

    Hydrochemical and multivariate statistical interpretations of 16 physicochemical parameters of 45 groundwater samples from a riverside alluvial aquifer underneath an agricultural area in Osong, central Korea, were performed in this study to understand the spatial controls of nitrate concentrations in terms of biogeochemical processes occurring near oxbow lakes within a fluvial plain. Nitrate concentrations in groundwater showed a large variability from 0.1 to 190.6 mg/L (mean = 35.0 mg/L) with significantly lower values near oxbow lakes. The evaluation of hydrochemical data indicated that the groundwater chemistry (especially, degree of nitrate contamination) is mainly controlled by two competing processes: 1) agricultural contamination and 2) redox processes. In addition, results of factorial kriging, consisting of two steps (i.e., co-regionalization and factor analysis), reliably showed a spatial control of the concentrations of nitrate and other redox-sensitive species; in particular, significant denitrification was observed restrictedly near oxbow lakes. The results of this study indicate that sub-oxic conditions in an alluvial groundwater system are developed geologically and geochemically in and near oxbow lakes, which can effectively enhance the natural attenuation of nitrate before the groundwater discharges to nearby streams. This study also demonstrates the usefulness of multivariate statistical analysis in groundwater study as a supplementary tool for interpretation of complex hydrochemical data sets.

  13. Hydrochemical and multivariate statistical interpretations of spatial controls of nitrate concentrations in a shallow alluvial aquifer around oxbow lakes (Osong area, central Korea).

    PubMed

    Kim, Kyoung-Ho; Yun, Seong-Taek; Choi, Byoung-Young; Chae, Gi-Tak; Joo, Yongsung; Kim, Kangjoo; Kim, Hyoung-Soo

    2009-07-21

    Hydrochemical and multivariate statistical interpretations of 16 physicochemical parameters of 45 groundwater samples from a riverside alluvial aquifer underneath an agricultural area in Osong, central Korea, were performed in this study to understand the spatial controls of nitrate concentrations in terms of biogeochemical processes occurring near oxbow lakes within a fluvial plain. Nitrate concentrations in groundwater showed a large variability from 0.1 to 190.6 mg/L (mean=35.0 mg/L) with significantly lower values near oxbow lakes. The evaluation of hydrochemical data indicated that the groundwater chemistry (especially, degree of nitrate contamination) is mainly controlled by two competing processes: 1) agricultural contamination and 2) redox processes. In addition, results of factorial kriging, consisting of two steps (i.e., co-regionalization and factor analysis), reliably showed a spatial control of the concentrations of nitrate and other redox-sensitive species; in particular, significant denitrification was observed restrictedly near oxbow lakes. The results of this study indicate that sub-oxic conditions in an alluvial groundwater system are developed geologically and geochemically in and near oxbow lakes, which can effectively enhance the natural attenuation of nitrate before the groundwater discharges to nearby streams. This study also demonstrates the usefulness of multivariate statistical analysis in groundwater study as a supplementary tool for interpretation of complex hydrochemical data sets.

  14. Predictive modeling of groundwater nitrate pollution using Random Forest and multisource variables related to intrinsic and specific vulnerability: a case study in an agricultural setting (Southern Spain).

    PubMed

    Rodriguez-Galiano, Victor; Mendes, Maria Paula; Garcia-Soldado, Maria Jose; Chica-Olmo, Mario; Ribeiro, Luis

    2014-04-01

    Watershed management decisions need robust methods, which allow an accurate predictive modeling of pollutant occurrences. Random Forest (RF) is a powerful machine learning data driven method that is rarely used in water resources studies, and thus has not been evaluated thoroughly in this field, when compared to more conventional pattern recognition techniques key advantages of RF include: its non-parametric nature; high predictive accuracy; and capability to determine variable importance. This last characteristic can be used to better understand the individual role and the combined effect of explanatory variables in both protecting and exposing groundwater from and to a pollutant. In this paper, the performance of the RF regression for predictive modeling of nitrate pollution is explored, based on intrinsic and specific vulnerability assessment of the Vega de Granada aquifer. The applicability of this new machine learning technique is demonstrated in an agriculture-dominated area where nitrate concentrations in groundwater can exceed the trigger value of 50 mg/L, at many locations. A comprehensive GIS database of twenty-four parameters related to intrinsic hydrogeologic proprieties, driving forces, remotely sensed variables and physical-chemical variables measured in "situ", were used as inputs to build different predictive models of nitrate pollution. RF measures of importance were also used to define the most significant predictors of nitrate pollution in groundwater, allowing the establishment of the pollution sources (pressures). The potential of RF for generating a vulnerability map to nitrate pollution is assessed considering multiple criteria related to variations in the algorithm parameters and the accuracy of the maps. The performance of the RF is also evaluated in comparison to the logistic regression (LR) method using different efficiency measures to ensure their generalization ability. Prediction results show the ability of RF to build accurate models

  15. 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

  16. Identifying pathways and processes affecting nitrate and orthophosphate inputs to streams in agricultural watersheds.

    PubMed

    Tesoriero, Anthony J; Duff, John H; Wolock, David M; Spahr, Norman E; Almendinger, James E

    2009-01-01

    Understanding nutrient pathways to streams will improve nutrient management strategies and estimates of the time lag between when changes in land use practices occur and when water quality effects that result from these changes are observed. Nitrate and orthophosphate (OP) concentrations in several environmental compartments were examined in watersheds having a range of base flow index (BFI) values across the continental United States to determine the dominant pathways for water and nutrient inputs to streams. Estimates of the proportion of stream nitrate that was derived from groundwater increased as BFI increased. Nitrate concentration gradients between groundwater and surface water further supported the groundwater source of nitrate in these high BFI streams. However, nitrate concentrations in stream-bed pore water in all settings were typically lower than stream or upland groundwater concentrations, suggesting that nitrate discharge to streams was not uniform through the bed. Rather, preferential pathways (e.g., springs, seeps) may allow high nitrate groundwater to bypass sites of high biogeochemical transformation. Rapid pathway compartments (e.g., overland flow, tile drains) had OP concentrations that were typically higher than in streams and were important OP conveyers in most of these watersheds. In contrast to nitrate, the proportion of stream OP that is derived from ground water did not systematically increase as BFI increased. While typically not the dominant source of OP, groundwater discharge was an important pathway of OP transport to streams when BFI values were very high and when geochemical conditions favored OP mobility in groundwater.

  17. Impacts of Agriculture on Nitrates in Soil and Groundwater in the Southeastern Coastal Plain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen (N) contamination of surface and groundwater is a health concern for both humans and animals. Excess N in surface water bodies may contribute to eutrophication. Elevated nitrate (NO3-N) concentrations in drinking water have caused infant death from the disease methemoglobinemia. Nitrates...

  18. The assessment of groundwater nitrate contamination by using logistic regression model in a representative rural area

    NASA Astrophysics Data System (ADS)

    Ko, K.; Cheong, B.; Koh, D.

    2010-12-01

    Groundwater has been used a main source to provide a drinking water in a rural area with no regional potable water supply system in Korea. More than 50 percent of rural area residents depend on groundwater as drinking water. Thus, research on predicting groundwater pollution for the sustainable groundwater usage and protection from potential pollutants was demanded. This study was carried out to know the vulnerability of groundwater nitrate contamination reflecting the effect of land use in Nonsan city of a representative rural area of South Korea. About 47% of the study area is occupied by cultivated land with high vulnerable area to groundwater nitrate contamination because it has higher nitrogen fertilizer input of 62.3 tons/km2 than that of country’s average of 44.0 tons/km2. The two vulnerability assessment methods, logistic regression and DRASTIC model, were tested and compared to know more suitable techniques for the assessment of groundwater nitrate contamination in Nonsan area. The groundwater quality data were acquired from the collection of analyses of 111 samples of small potable supply system in the study area. The analyzed values of nitrate were classified by land use such as resident, upland, paddy, and field area. One dependent and two independent variables were addressed for logistic regression analysis. One dependent variable was a binary categorical data with 0 or 1 whether or not nitrate exceeding thresholds of 1 through 10 mg/L. The independent variables were one continuous data of slope indicating topography and multiple categorical data of land use which are classified by resident, upland, paddy, and field area. The results of the Levene’s test and T-test for slope and land use were showed the significant difference of mean values among groups in 95% confidence level. From the logistic regression, we could know the negative correlation between slope and nitrate which was caused by the decrease of contaminants inputs into groundwater with

  19. Residence times of groundwater and nitrate transport in coastal aquifer systems: Daweijia area, northeastern China.

    PubMed

    Han, Dongmei; Cao, Guoliang; McCallum, James; Song, Xianfang

    2015-12-15

    Groundwater within the coastal aquifer systems of the Daweijia area in northeastern China is characterized by a large of variations (33-521mg/L) in NO3(-) concentrations. Elevated nitrate concentrations, in addition to seawater intrusion in the Daweijia well field, both attributable to anthropogenic activities, may impact future water-management practices. Chemical and stable isotopic (δ(18)O, δ(2)H) analysis, (3)H and CFCs methods were applied to provide a better understanding of the relationship between the distribution of groundwater mean residence time (MRT) and nitrate transport, and to identify sources of nitrate concentrations in the complex coastal aquifer systems. There is a relatively narrow range of isotopic composition (ranging from -8.5 to -7.0‰) in most groundwater. Generally higher tritium contents observed in the wet season relative to the dry season may result from rapid groundwater circulation in response to the rainfall through the preferential flow paths. In the well field, the relatively increased nitrate concentrations of groundwater, accompanied by the higher tritium contents in the wet season, indicate the nitrate pollution can be attributed to domestic wastes. The binary exponential and piston-flow mixing model (BEP) yielded feasible age distributions based on the conceptual model. The good inverse relationship between groundwater MRTs (92-467years) and the NO3(-) concentrations in the shallow Quaternary aquifers indicates that elevated nitrate concentrations are attributable to more recent recharge for shallow groundwater. However, there is no significant relationship between the MRTs (8-411years) and the NO3(-) concentrations existing in the carbonate aquifer system, due to the complex hydrogeological conditions, groundwater age distributions and the range of contaminant source areas. Nitrate in the groundwater system without denitrification effects could accumulate and be transported for tens of years, through the complex carbonate

  20. Residence times of groundwater and nitrate transport in coastal aquifer systems: Daweijia area, northeastern China.

    PubMed

    Han, Dongmei; Cao, Guoliang; McCallum, James; Song, Xianfang

    2015-12-15

    Groundwater within the coastal aquifer systems of the Daweijia area in northeastern China is characterized by a large of variations (33-521mg/L) in NO3(-) concentrations. Elevated nitrate concentrations, in addition to seawater intrusion in the Daweijia well field, both attributable to anthropogenic activities, may impact future water-management practices. Chemical and stable isotopic (δ(18)O, δ(2)H) analysis, (3)H and CFCs methods were applied to provide a better understanding of the relationship between the distribution of groundwater mean residence time (MRT) and nitrate transport, and to identify sources of nitrate concentrations in the complex coastal aquifer systems. There is a relatively narrow range of isotopic composition (ranging from -8.5 to -7.0‰) in most groundwater. Generally higher tritium contents observed in the wet season relative to the dry season may result from rapid groundwater circulation in response to the rainfall through the preferential flow paths. In the well field, the relatively increased nitrate concentrations of groundwater, accompanied by the higher tritium contents in the wet season, indicate the nitrate pollution can be attributed to domestic wastes. The binary exponential and piston-flow mixing model (BEP) yielded feasible age distributions based on the conceptual model. The good inverse relationship between groundwater MRTs (92-467years) and the NO3(-) concentrations in the shallow Quaternary aquifers indicates that elevated nitrate concentrations are attributable to more recent recharge for shallow groundwater. However, there is no significant relationship between the MRTs (8-411years) and the NO3(-) concentrations existing in the carbonate aquifer system, due to the complex hydrogeological conditions, groundwater age distributions and the range of contaminant source areas. Nitrate in the groundwater system without denitrification effects could accumulate and be transported for tens of years, through the complex carbonate

  1. Using Nitrate N and O Isotope Ratios to Identify Nitrate Sources and Dominant Nitrogen Cycling Processes in a 12ha Tile Drained Dryland Agricultural Field in the Palouse Basin of Eastern Washington State

    NASA Astrophysics Data System (ADS)

    Kelley, C. J.; Keller, C. K.; Evans, R. D.; Orr, C. H.; Smith, J. L.

    2010-12-01

    Agricultural systems are a leading source of reactive nitrogen to aquatic and atmospheric ecosystem. Understanding how anthropogenic nitrogen sources are cycled during transport from agricultural systems to aquatic and atmospheric systems is essential to identify the sink(s) of missing nitrogen and improve nitrogen management. Here we use natural nitrate 15N and 18O isotope abundances to determine the timing of nitrogen cycling process and to identify the source of nitrate discharged from a tile drained section of the WSU Cook Agronomy Farm. Previous research at the Cook Farm has shown that 5% to 20% of fertilizer nitrogen leaves the system as nitrate through the tile-drain. Identifying the timing of nitrogen cycling events and identifying the source(s) of tile drain nitrate is the first step to reduce nitrogen loss to aquatic systems bordering agricultural land. Throughout the 5 year study period δ18Onitrate averaged -1.26±1.48‰, indicating that nitrate-oxygen isotopes were not being enriched. Tile drain nitrate δ15N varied seasonally from -0.48‰ in the winter to +9.24‰ during the summer with an average of +3.19±2.62‰. The lack of nitrate-oxygen enrichment during the study period indicates that nitrification is the dominant nitrogen cycling process in the tile drained soil. The expected δ18Onitrate from nitrification based on the nitrification equation is -2.0‰, also supporting the claim that nitrification is the dominant nitrogen cycling process in the soil drained by the tile drain system. The large range of nitrate δ15N overlaps the expected isotope values for nitrate from nitrified synthetic nitrogen fertilizers and soil organic nitrogen. Nitrate-nitrogen and nitrate-oxygen isotope abundances have shown that nitrate in high nitrate concentration TD discharge originates from nitrification of reduced nitrogen fertilizers and nitrate in low nitrate concentration TD discharge originates from nitrification of; 1) soil organic nitrogen, 2) biotically

  2. RIPARIAN AREAS OF AN AGRICULTURAL LANDSCAPE IN WESTERN OREGON

    EPA Science Inventory

    The Willamette Valley is a productive, diversified agricultural area in western Oregon. Pastureland and grass seed fields, mostly located on poorly drained soils, account for 60% of the agricultural land in the valley. The size and character of Willamette Valley streams and ass...

  3. A threshold area ratio of organic to conventional agriculture causes recurrent pathogen outbreaks in organic agriculture.

    PubMed

    Adl, S; Iron, D; Kolokolnikov, T

    2011-05-01

    Conventional agriculture uses herbicides, pesticides, and chemical fertilizers that have the potential to pollute the surrounding land, air and water. Organic agriculture tries to avoid using these and promotes an environmentally friendly approach to agriculture. Instead of relying on herbicides, pesticides and chemical fertilizers, organic agriculture promotes a whole system approach to managing weeds, pests and nutrients, while regulating permitted amendments. In this paper, we consider the effect of increasing the total area of agricultural land under organic practices, against a background of conventional agriculture. We hypothesized that at a regional scale, organic agriculture plots benefit from existing in a background of conventional agriculture, that maintains low levels of pathogens through pesticide applications. We model pathogen dispersal with a diffusive logistic equation in which the growth/death rate is spatially heterogeneous. We find that if the ratio of the organic plots to conventional plots remains below a certain threshold l(c), the pest population is kept small. Above this threshold, the pest population in the organic plots grows rapidly. In this case, the area in organic agriculture will act as a source of pest to the surrounding region, and will always infect organic plots as they become more closely spaced. Repeated localized epidemics of pest outbreaks threaten global food security by reducing crop yields and increasing price volatility. We recommend that regional estimates of this threshold are necessary to manage the growth of organic agriculture region by region.

  4. A threshold area ratio of organic to conventional agriculture causes recurrent pathogen outbreaks in organic agriculture.

    PubMed

    Adl, S; Iron, D; Kolokolnikov, T

    2011-05-01

    Conventional agriculture uses herbicides, pesticides, and chemical fertilizers that have the potential to pollute the surrounding land, air and water. Organic agriculture tries to avoid using these and promotes an environmentally friendly approach to agriculture. Instead of relying on herbicides, pesticides and chemical fertilizers, organic agriculture promotes a whole system approach to managing weeds, pests and nutrients, while regulating permitted amendments. In this paper, we consider the effect of increasing the total area of agricultural land under organic practices, against a background of conventional agriculture. We hypothesized that at a regional scale, organic agriculture plots benefit from existing in a background of conventional agriculture, that maintains low levels of pathogens through pesticide applications. We model pathogen dispersal with a diffusive logistic equation in which the growth/death rate is spatially heterogeneous. We find that if the ratio of the organic plots to conventional plots remains below a certain threshold l(c), the pest population is kept small. Above this threshold, the pest population in the organic plots grows rapidly. In this case, the area in organic agriculture will act as a source of pest to the surrounding region, and will always infect organic plots as they become more closely spaced. Repeated localized epidemics of pest outbreaks threaten global food security by reducing crop yields and increasing price volatility. We recommend that regional estimates of this threshold are necessary to manage the growth of organic agriculture region by region. PMID:21420722

  5. Pesticides in wells in agricultural and urban areas of the Hudson River basin

    USGS Publications Warehouse

    Phillips, P.J.; Wall, G.R.; Ryan, C.M.

    2000-01-01

    herbicides (atrazine and prometon), and one herbicide metabolite (deethylatrazine). Samples from the urban/residential water-supply well network contained two insecticides (diazinon and malathion), and three herbicides (atrazine, metolachlor, and prometon). Pesticides were detected in samples from depths of less than 2 to more than 70 m. Pesticides were detected in samples with nitrate concentrations ranging from less than the detection limit of 0.05 mg/L to 16 mg/L. These results indicate that pesticides are detected most frequently in shallow ground water beneath agricultural areas, and that pesticides can be detected in wells with a wide range of depths and nitrate concentrations.

  6. Spectral Characterization of Agricultural Burned Areas for Satellite Mapping

    NASA Astrophysics Data System (ADS)

    Boren, Erik J.

    Burned area detection with remotely sensed satellite data in agricultural landscapes is not only necessary for the estimation of global biomass burning emissions, but also has gained attention from managers interested in improved methods for the quantification of local scale emissions which affect air quality and human health. Mapping agricultural burned areas accurately, precisely and reliably, with methods that can be applied globally, is difficult because of the spectral and temporal characteristics of agricultural regions and prescribed cropland fires. These challenges have not been fully addressed by the scientific literature. Chapter 1 of this thesis presents an extensive literature review on the methods currently used for agricultural burned area mapping. Chapter 2 presents original research on the spectral characterization of agricultural burned areas, using field data and mixture models to analyze the response of spectral indices to the changes induced by fire and agricultural practices. The conclusions summarize the significance of the presented research for understanding the potential and limits of satellite data for agricultural burned area monitoring, and outline the directions for future work.

  7. Nitrate leaching in agriculture to upper groundwater in the sandy regions of the Netherlands during the 1992-1995 period.

    PubMed

    Boumans, Leo J M; Fraters, Dico; Van Drecht, Gerard

    2005-03-01

    The Dutch National Monitoring Programme for Effectiveness of the Minerals Policy (LMM) was initiated to allow detection of a statutory reduction in nitrate leaching caused by a decreasing N load. The starting point, or baseline, was taken as the nitrate concentration of the upper metre of groundwater sampled on 99 farms in the 1992-1995 period in the sandy areas of the Netherlands, where predominantly grass and maize grow. We found here that a reduction in nitrate leaching of more than 20% in future would almost certainly be detected with the LMM. Detecting downward trends due to decreasing N load will require nitrate concentrations to also be related to soil drainage, precipitation excess leading to groundwater recharge and to location. Furthermore, we found that about 16% of the N load in the Dutch sandy regions was being leached to the upper metre of groundwater in the 1992-1995 period. The critical N load in approximately 1990 for exceeding the EC limit value for nitrate, NO3, (50 mg L(-1)) in the upper metre of groundwater for the mean situation for grassland, maize and arable land in the sandy area was found to be 210 kg ha(-1) a(-1). Because manure management has been altered, the critical load found will be lower than the current critical load. PMID:15869188

  8. Nitrate leaching in agriculture to upper groundwater in the sandy regions of the Netherlands during the 1992-1995 period.

    PubMed

    Boumans, Leo J M; Fraters, Dico; Van Drecht, Gerard

    2005-03-01

    The Dutch National Monitoring Programme for Effectiveness of the Minerals Policy (LMM) was initiated to allow detection of a statutory reduction in nitrate leaching caused by a decreasing N load. The starting point, or baseline, was taken as the nitrate concentration of the upper metre of groundwater sampled on 99 farms in the 1992-1995 period in the sandy areas of the Netherlands, where predominantly grass and maize grow. We found here that a reduction in nitrate leaching of more than 20% in future would almost certainly be detected with the LMM. Detecting downward trends due to decreasing N load will require nitrate concentrations to also be related to soil drainage, precipitation excess leading to groundwater recharge and to location. Furthermore, we found that about 16% of the N load in the Dutch sandy regions was being leached to the upper metre of groundwater in the 1992-1995 period. The critical N load in approximately 1990 for exceeding the EC limit value for nitrate, NO3, (50 mg L(-1)) in the upper metre of groundwater for the mean situation for grassland, maize and arable land in the sandy area was found to be 210 kg ha(-1) a(-1). Because manure management has been altered, the critical load found will be lower than the current critical load.

  9. The influence of nitrate on selenium in irrigated agricultural groundwater systems.

    PubMed

    Bailey, Ryan T; Hunter, William J; Gates, Timothy K

    2012-01-01

    Selenium (Se) contamination of groundwater is an environmental concern especially in areas where aquifer systems are underlain by Se-bearing geologic formations such as marine shale. This study examined the influence of nitrate (NO₃) on Se species in irrigated soil and groundwater systems and presents results from field and laboratory studies that further clarify this influence. Inhibition of selenate (SeO₄) reduction in the presence of NO₃ and the oxidation of reduced Se from shale by autotrophic denitrification were investigated. Groundwater sampling from piezometers near an alluvium-shale interface suggests that SeO₄ present in the groundwater was due in part to autotrophic denitrification. Laboratory shale oxidation batch studies indicate that autotrophic denitrification is a major driver in the release of SeO₄ and sulfate. Similar findings occurred for a shale oxidation flow-through column study, with 70 and 31% more reduced Se and S mass, respectively, removed from the shale material in the presence of NO₃ than in its absence. A final laboratory flow-through column test was performed with shallow soil samples to assess the inhibition of SeO₄ reduction in the presence of NO₃, with results suggesting that a concentration of NO₃ of approximately 5 mg L or greater will diminish the reduction of SeO₄. The inclusion of the fate and transport of NO₃ and dissolved oxygen is imperative when studying or simulating the fate and transport of Se species in soil and groundwater systems.

  10. Pollution of drinking water with nitrate

    SciTech Connect

    Cabel, B.; Kozicki, R.; Lahl, U.; Podbielshi, A.; Stachel, B.; Struss, S.

    1982-01-01

    The main sources of nitrate in man are food and drinking water. The legislature in West Germany intends to lower the permitted level of nitrate in drinking water from the present 90 mg/l to 50 mg/l in 1982. The European Community has issued a directive that recommends a level of only 25 mg/l, and for babies 10 mg/l nitrate should not be exceeded. At present, nitrate cannot be removed from raw water at an acceptable cost. The problem of high nitrate content is mainly one of drinking water generation from ground water. Several analyses indicate rising concentrations of nitrate in ground water in different regions of West Germany, especially in the last few years. The following sources of nitrate-contamination of ground water aquifers in West are discussed: natural sources; over-manuring of agricultural areas with natural organic fertilizers; over-manuring of agricultural areas with synthetic fertilizers.

  11. Identifying pathways and processes affecting nitrate and orthophosphate inputs to streams in agricultural watersheds

    USGS Publications Warehouse

    Tesoriero, A.J.; Duff, J.H.; Wolock, D.M.; Spahr, N.E.; Almendinger, J.E.

    2009-01-01

    Understanding nutrient pathways to streams will improve nutrient management strategies and estimates of the time lag between when changes in land use practices occur and when water quality effects that result from these changes are observed. Nitrate and orthophosphate (OP) concentrations in several environmental compartments were examined in watersheds having a range of base flow index (BFI) values across the continental United States to determine the dominant pathways for water and nutrient inputs to streams. Estimates of the proportion of stream nitrate that was derived from groundwater increased as BFI increased. Nitrate concentration gradients between groundwater and surface water further supported the groundwater source of nitrate in these high BFI streams. However, nitrate concentrations in stream-bed pore water in all settings were typically lower than stream or upland groundwater concentrations, suggesting that nitrate discharge to streams was not uniform through the bed. Rather, preferential pathways (e.g., springs, seeps) may allow high nitrate groundwater to bypass sites of high biogeochemical transformation. Rapid pathway compartments (e.g., overland flow, tile drains) had OP concentrations that were typically higher than in streams and were important OP conveyers in most of these watersheds. In contrast to nitrate, the proportion of stream OP that is derived from ground water did not systematically increase as BFI increased. While typically not the dominant source of OP, groundwater discharge was an important pathway of OP transport to streams when BFI values were very high and when geochemical conditions favored OP mobility in groundwater. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  12. The importance of the riparian zone and in-stream processes in nitrate attenuation in undisturbed and agricultural watersheds – a review of the scientific literature

    USGS Publications Warehouse

    Ranalli, Anthony J.; MacAlady, Donald L.

    2010-01-01

    We reviewed published studies from primarily glaciated regions in the United States, Canada, and Europe of the (1) transport of nitrate from terrestrial ecosystems to aquatic ecosystems, (2) attenuation of nitrate in the riparian zone of undisturbed and agricultural watersheds, (3) processes contributing to nitrate attenuation in riparian zones, (4) variation in the attenuation of nitrate in the riparian zone, and (5) importance of in-stream and hyporheic processes for nitrate attenuation in the stream channel. Our objectives were to synthesize the results of these studies and suggest methodologies to (1) monitor regional trends in nitrate concentration in undisturbed 1st order watersheds and (2) reduce nitrate loads in streams draining agricultural watersheds. Our review reveals that undisturbed headwater watersheds have been shown to be very retentive of nitrogen, but the importance of biogeochemical and hydrological riparian zone processes in retaining nitrogen in these watersheds has not been demonstrated as it has for agricultural watersheds. An understanding of the role of the riparian zone in nitrate attenuation in undisturbed watersheds is crucial because these watersheds are increasingly subject to stressors, such as changes in land use and climate, wildfire, and increases in atmospheric nitrogen deposition. In general, understanding processes controlling the concentration and flux of nitrate is critical to identifying and mapping the vulnerability of watersheds to water quality changes due to a variety of stressors. In undisturbed and agricultural watersheds we propose that understanding the importance of riparian zone processes in 2nd order and larger watersheds is critical. Research is needed that addresses the relative importance of how the following sources of nitrate along any given stream reach might change as watersheds increase in size and with flow: (1) inputs upstream from the reach, (2) tributary inflow, (3) water derived from the riparian zone

  13. The impact of the Nitrates Directive on nitrogen emissions from agriculture in the EU-27 during 2000-2008.

    PubMed

    Velthof, G L; Lesschen, J P; Webb, J; Pietrzak, S; Miatkowski, Z; Pinto, M; Kros, J; Oenema, O

    2014-01-15

    A series of environmental policies have been implemented in the European Union (EU) to decrease nitrogen (N) emissions from agriculture. The Nitrates Directive (ND) is one of the main policies; it aims to reduce nitrate leaching from agriculture through a number of measures. A study was carried out to quantify the effects of the ND in the EU-27 on the leaching and runoff of nitrate (NO3(-)) to groundwater and surface waters, and on the emissions of ammonia (NH3), nitrous oxide (N2O), nitrogen oxides (NO(x)) and dinitrogen (N2) to the atmosphere. We formulated a scenario with and a scenario without implementation of the ND. The model MITERRA-Europe was used to calculate N emissions on a regional level in the EU-27 for the period 2000-2008. The calculated total N loss from agriculture in the EU-27 was 13 Mton N in 2008, with 53% as N2, 22% as NO3, 21% as NH3, 3% as N2O, and 1% as NO(x). The N emissions and leaching in the EU-27 slightly decreased in the period 2000-2008. Total emissions in the EU in 2008 were smaller with implementation of the ND than without the ND, by 3% for NH3, 6% for N2O, 9% for NO(x), and 16% for N leaching and runoff in 2008. However, regional differences were large. The lower emissions with ND were mainly due to the lower N inputs by fertilizers and manures. In conclusion, implementation of the ND decreased both N leaching losses to ground and surface waters, and gaseous emissions to the atmosphere. It is expected that the ND will result in a further decrease in N emissions in EU-27 in the near future, because the implementation of the measures for the ND is expected to become more strict. PMID:23731510

  14. The impact of the Nitrates Directive on nitrogen emissions from agriculture in the EU-27 during 2000-2008.

    PubMed

    Velthof, G L; Lesschen, J P; Webb, J; Pietrzak, S; Miatkowski, Z; Pinto, M; Kros, J; Oenema, O

    2014-01-15

    A series of environmental policies have been implemented in the European Union (EU) to decrease nitrogen (N) emissions from agriculture. The Nitrates Directive (ND) is one of the main policies; it aims to reduce nitrate leaching from agriculture through a number of measures. A study was carried out to quantify the effects of the ND in the EU-27 on the leaching and runoff of nitrate (NO3(-)) to groundwater and surface waters, and on the emissions of ammonia (NH3), nitrous oxide (N2O), nitrogen oxides (NO(x)) and dinitrogen (N2) to the atmosphere. We formulated a scenario with and a scenario without implementation of the ND. The model MITERRA-Europe was used to calculate N emissions on a regional level in the EU-27 for the period 2000-2008. The calculated total N loss from agriculture in the EU-27 was 13 Mton N in 2008, with 53% as N2, 22% as NO3, 21% as NH3, 3% as N2O, and 1% as NO(x). The N emissions and leaching in the EU-27 slightly decreased in the period 2000-2008. Total emissions in the EU in 2008 were smaller with implementation of the ND than without the ND, by 3% for NH3, 6% for N2O, 9% for NO(x), and 16% for N leaching and runoff in 2008. However, regional differences were large. The lower emissions with ND were mainly due to the lower N inputs by fertilizers and manures. In conclusion, implementation of the ND decreased both N leaching losses to ground and surface waters, and gaseous emissions to the atmosphere. It is expected that the ND will result in a further decrease in N emissions in EU-27 in the near future, because the implementation of the measures for the ND is expected to become more strict.

  15. Can rehabilitation techniques in agricultural streams influence transient storage and nitrate uptake?

    NASA Astrophysics Data System (ADS)

    Mueller Price, J.; Baker, D. W.; Bledsoe, B.

    2009-12-01

    Headwater streams are a crucial component of nutrient processing in watersheds, partly due to high surface-to-volume ratios that favor nitrate uptake and to the large percentage of headwater stream length in the total length of a river system. We explore the potential of two stream rehabilitation approaches in headwater streams to promote nitrate uptake and reduce down-stream nitrogen pollution. We investigated two streams, Sheep Creek and Nunn Creek, located in northern Colorado that have been influenced by live-stock grazing. Sections of Sheep Creek were fenced off and exclosed from open rangeland cattle grazing in the 1950s, allowing riparian corridors of these sections to naturally revegetate, while other sections have been continu-ally grazed. In 2003, restoration structures of rootwads and j-hook vanes were constructed along portions of Nunn Creek for bank stabilization and trout habitat enhancement. We studied four reaches along Sheep Creek, two reaches exclosed from grazing and two reaches currently grazed. We also studied two reaches along Nunn Creek, one with restoration structures and one without structures. We performed nutrient injections of bromide and nitrate to estimate transient storage and nitrate uptake in each reach. Comprehensive data sets were also collected to characterize physical complexity along each reach, including pebble counts, longitudinal profiles, cross-section surveys, hydraulic measurements, benthic organic matter (fine and coarse), and spatial distribution of physical habitat units. We developed regression models that relate parameters of geomorphic complexity with transient storage and nitrate uptake parameters to describe how the geomorphic complexity associated with rehabilitation techniques in each reach can influence transient storage and nitrate uptake.

  16. Shallow Ground-Water Quality in Agricultural Areas of Northern Alabama and Middle Tennessee, 2000-2001

    USGS Publications Warehouse

    Kingsbury, James A.

    2003-01-01

    As part of the U.S. Geological Survey National Water-Quality Assessment Program, 32 monitoring wells were installed near cropland in parts of northern Alabama and Middle Tennessee to characterize the effect of row-crop agriculture on shallow ground-water quality. The wells were completed in regolith overlying carbonate bedrock. These geologic units are part of the Mississippian carbonate aquifer, a source of drinking water for domestic and municipal supply in the area. The majority of these wells were sampled in the spring of 2000 for inorganic constituents, nutrients, pesticides, and selected pesticide degradates. Land use and soil characteristics were delineated for a 1,640-foot radius buffer area around each well to relate water quality to environmental factors. A strong association among soil characteristics, land use, and hydrogeology limited the analysis of the effect of these factors on nitrate and pesticide occurrence. Nitrate and pesticide concentrations generally were low, and no samples exceeded established drinking-water maximum contaminant levels. The maximum concentration of nitrate was about 8 milligrams per liter as nitrogen, and the median concentration was 1 milligram per liter. Nitrate concentrations were strongly correlated to dissolved-oxygen concentrations, and ratios of chloride to nitrate indicate nitrate concentrations were affected by denitrification in about a third of the samples. A pesticide or pesticide degradate was detected at concentrations greater than 0.01 microgram per liter in 91 percent of the samples. Pesticides with the highest use typically were detected most frequently and at the highest concentrations; however, glyphosate had the highest estimated use but was not detected in any samples. Fluometuron and atrazine, two high-use pesticides, were detected in 83 and 70 percent, respectively, of the samples from wells where the pesticide was applied in the buffer area. Maximum concentrations of fluometuron and atrazine were 2

  17. Does irrigation with reclaimed water significantly pollute shallow aquifer with nitrate and salinity? An assay in a perurban area in North Tunisia.

    PubMed

    Anane, Makram; Selmi, Youssef; Limam, Atef; Jedidi, Naceur; Jellali, Salah

    2014-07-01

    In Tunisia, reclaimed water is increasingly used for irrigation in order to mitigate water shortage. However, few studies have addressed the effect of such practice on the environment. Thus, we attempted in this paper to assess the impact of irrigation with reclaimed water on the nitrate content and salinity in the Nabeul shallow aquifer on the basis of satellite images and data from 53 sampled wells. Ordinary and indicator kriging were used to map the spatial variability of these groundwater chemical parameters and to locate the areas where water is suitable for drinking and irrigation. The results of this study have shown that reclaimed water is not an influential factor on groundwater contamination by nitrate and salinity. Cropping density is the main factor contributing to nitrate groundwater pollution, whereas salinity pollution is affected by a conjunction of factors such as seawater interaction and lithology. The predictive maps show that nitrate content in the groundwater ranges from 9.2 to 206 mg/L while the electric conductivity ranges from 2.2 to 8.5 dS/m. The high-nitrate concentration areas underlie sites with high annual crop density, whereas salinity decreases gradually moving away from the coastline. The probability maps reveal that almost the entire study area is unsuitable for drinking with regard to nitrate and salinity levels. Appropriate measures, such as the elaboration of codes of good agricultural practices and action programs, should be undertaken in order to prevent and/or remediate the contamination of the Nabeul shallow aquifer.

  18. Does irrigation with reclaimed water significantly pollute shallow aquifer with nitrate and salinity? An assay in a perurban area in North Tunisia.

    PubMed

    Anane, Makram; Selmi, Youssef; Limam, Atef; Jedidi, Naceur; Jellali, Salah

    2014-07-01

    In Tunisia, reclaimed water is increasingly used for irrigation in order to mitigate water shortage. However, few studies have addressed the effect of such practice on the environment. Thus, we attempted in this paper to assess the impact of irrigation with reclaimed water on the nitrate content and salinity in the Nabeul shallow aquifer on the basis of satellite images and data from 53 sampled wells. Ordinary and indicator kriging were used to map the spatial variability of these groundwater chemical parameters and to locate the areas where water is suitable for drinking and irrigation. The results of this study have shown that reclaimed water is not an influential factor on groundwater contamination by nitrate and salinity. Cropping density is the main factor contributing to nitrate groundwater pollution, whereas salinity pollution is affected by a conjunction of factors such as seawater interaction and lithology. The predictive maps show that nitrate content in the groundwater ranges from 9.2 to 206 mg/L while the electric conductivity ranges from 2.2 to 8.5 dS/m. The high-nitrate concentration areas underlie sites with high annual crop density, whereas salinity decreases gradually moving away from the coastline. The probability maps reveal that almost the entire study area is unsuitable for drinking with regard to nitrate and salinity levels. Appropriate measures, such as the elaboration of codes of good agricultural practices and action programs, should be undertaken in order to prevent and/or remediate the contamination of the Nabeul shallow aquifer. PMID:24676992

  19. Performance Monitoring: Evaluating a Wheat Straw PRB for Nitrate Removal at an Agricultural Operation

    EPA Science Inventory

    The U.S. EPA Office of Research and Development’s National Risk Management Research Laboratory (NRMRL) is conducting long-term monitoring of a wheat straw permeable reactive barrier (PRB) for remediation of ground water contaminated with nitrate from a now-closed swine concentrat...

  20. 78 FR 35258 - Solid Agricultural Grade Ammonium Nitrate from Ukraine: Continuation of Antidumping Duty Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-12

    ... (``Sunset'') Review, 77 FR 32527 (June 1, 2012); and Ammonium Nitrate from Ukraine: Institution of a Five-Year Review, Investigation No. 731-TA-894 (Second Review), 77 FR 32669 (June 1, 2012). \\3\\ See Solid..., 66 FR 47451 (September 12, 2001) (``the Order''). DATES: Effective Date: June 12, 2013. ] FOR...

  1. High resolution modeling of agricultural nitrogen to identify private wells susceptible to nitrate contamination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oregon’s Domestic Well Testing Act (DWTA) links testing to property sales enabling continuous data collection on private water sources. This study investigates use of DWTA data as a sentinel surveillance system for monitoring exposures to well contaminants, particularly nitrate. A land use regressio...

  2. Shallow ground-water quality in selected agricultural areas of south-central Georgia, 1994

    USGS Publications Warehouse

    Crandall, C.A.

    1996-01-01

    The Georgia-Florida Coastal Plain National Water-Quality Assessment Program began an agricultural land-use study in March 1994. The study area is located in the upper Suwannee River basin in Tift, Turner, Worth, Irwin, Wilcox, and Crisp Counties, Ga. Twenty-three shallow monitoring wells were installed in a 1,335-square- mile area characterized by intensive row-crop agriculture (peanuts, corn, cotton, and soybeans). The study focused on recently recharged shallow ground water in surficial aquifers to assess the relation between land-use activities and ground- water quality. All wells were sampled in March and April (spring) 1994, and 14 of these wells were resampled in August (summer) 1994. Shallow ground water in the study area is characterized by oxic and acidic conditions, low bicarbonate, and low dissolved-solids concentrations. The median pH of shallow ground water was 4.7 and the median bicarbonate concentration was 1.7 mg/L (milligrams per liter). Dissolved oxygen concentrations ranged from 3.0 to 8.0 mg/L. The median dissolved-solids concentration in samples collected in the spring was 86 mg/L. Major inorganic ion composition was generally mixed with no dominant cation; nitrate was the dominant anion (greater than 60 percent of the anion composition) in 14 of 23 samples. Only concentrations of bicarbonate, dissolved organic carbon, and nitrate had significant differences in concentrations between samples collected in the spring and the background samples. However, median concentrations of some of the major ingredients in fertilizer (including magnesium, chloride, nitrate, iron, and manganese) were higher in water samples from agricultural wells than in background samples. The median concentration of dissolved solids in ground-water samples collected in the spring (86 mg/L) was more than double the median concentration (41 mg/L) of the background samples. The median nitrate as nitrogen concentration of 6.7 mg/L in the spring samples reflects the effects of

  3. Arsenic, nitrate, iron, and hardness in ground water, Fairbanks area, Alaska

    USGS Publications Warehouse

    Johnson, Paula R.; Wilcox, D.E.; Morgan, W.D.; Merto, Josephine; McFadden, Ruth

    1979-01-01

    Well water with concentrations of arsenic and nitrate exceeding U.S. Environmental Protection Agency standards occurs sporadically throughout the hills north of Fairbanks, Alaska. The arsenic contamination has not been correlated with placer or other mining activity. The high levels of nitrate do not generally appear related to septic waste contamination. Few wells in the Fairbanks area yield water with low concentrations of iron or low hardness. Iron concentrations are consistently greater than 3 mg/L on the flood plain. In the uplands, concentrations of both iron and hardness are lowest near the ridgetops and increase downslope. The report includes a map of the area showing the location of sampled wells and a table of chemical analysis. (Woodard-USGS)

  4. Groundwater chemistry in the nitrate contaminated area in Shimabara, Nagasaki Prefecture, Japan

    NASA Astrophysics Data System (ADS)

    Nakagawa, K.

    2014-12-01

    Groundwater contamination by nitrate from agricultural fields is a problem shared by many parts of the world. Shimabara, Nagasaki prefecture, Japan is an important agricultural district experiencing this problem. In Shimabara, drinking water relies on the groundwater. In this study, groundwater samples were collected at 40 locations such as residents and municipal waterworks wells, springs and rivers from August 2011 to November 2013. NO3-N concentration of 15 samples exceeded 10 mg L-1 (drinking water standard in Japan). Maximum NO3-N concentration was 26.6 mg L-1. Correlation coefficients were calculated between ion components of collected samples (n=277). NO3- had the highest positive correlation with Cl-(r =0.956) and had positive correlation with K+(r=0.679), SO42-(r=0.654) and Ca2+(r=0.593), respectively. The results revealed that Cl- and K+ related to livestock wastes, SO42- related to chemical fertilizers and Ca2+ related to calcareous materials. Main source of NO3- is from livestock wastes. To understand groundwater chemistry in detail, principal component analysis (PCA) and cluster analysis were carried out. Result from the PCA, chemical characteristics of groundwater was summarized by the first principal component and the second principal component. Both of two principal components reflected nitrate contamination and ion dissolution from aquifer matrix during groundwater flows. Result from the cluster analysis, chemical characteristics of groundwater was classified into four clusters. Nitrate polluted samples into specific cluster and the rest samples were classified into other clusters depending on the original water quality.

  5. Watershed Analysis of Nitrate Transport as a Result of Agricultural Inputs for Varying Land Use/Land Cover and Soil Type

    NASA Astrophysics Data System (ADS)

    Scott, M. E.; Sykes, J. F.

    2006-12-01

    The Grand River Watershed is one of the largest watersheds in southwestern Ontario with an area of approximately 7000 square kilometers. Ninety percent of the watershed is classified as rural, and 80 percent of the watershed population relies on groundwater as their source of drinking water. Management of the watershed requires the determination of the effect of agricultural practices on long-term groundwater quality and to identify locations within the watershed that are at a higher risk of contamination. The study focuses on the transport of nitrate through the root zone as a result of agricultural inputs with attenuation due to biodegradation. The driving force for transport is spatially and temporally varying groundwater recharge that is a function of land use/land cover, soil and meteorological inputs that yields 47,229 unique soil columns within the watershed. Fertilizer sources are determined from Statistics Canada's Agricultural Census and include livestock manure and a popular commercial fertilizer, urea. Accounting for different application rates yields 60,066 unique land parcels of which 22,809 are classified as croplands where manure and inorganic fertilizes are directly applied. The transport for the croplands is simulated over a 14-year period to investigate the impact of seasonal applications of nitrate fertilizers on the concentration leaching from the root zone to the water table. Based on land use/land cover maps, ArcView GIS is used to define the location of fertilizer applications within the watershed and to spatially visualize data and analyze results. The large quantity of input data is stored and managed using MS-Access and a relational database management system. Nitrogen transformations and ammonium and nitrate uptake by plants and transport through the soil column are simulated on a daily basis using Visual Basic for Applications (VBA) within MS-Access modules. Nitrogen transformations within the soil column were simplified using

  6. Nonpoint-source agricultural chemicals in ground water in Nebraska; preliminary results for six areas of the High Plains Aquifer

    USGS Publications Warehouse

    Chen, Hsiu-Hsiung; Druliner, A.D.

    1987-01-01

    The reconnaissance phase of a study to determine the occurrence of agricultural chemicals from nonpoint sources in groundwater in six areas, which represented the major provinces of the High Plains aquifer in Nebraska is described. In 1984, water from 82 wells in the 6 study areas was analyzed for nitrate, and water from 57 of the 82 wells was analyzed for triazine herbicides. Data for 9 of the 21 independent variables suspected of affecting concentrations of nitrate and triazine herbicides in groundwater were compiled from the 82 well sites. The variables and their ranges are: hydraulic gradient (XI), 0.006-0.0053; hydraulic conductivity (X2), 5-149 ft/day; specific discharge (X3), 0.0128-0.2998 ft/day; depth to water (X4), 3-239 ft; well depth (X5), 40-550 ft; annual precipitation (X6), 12.0-39.3 inches; soil permeability (X7), 0.76-9.0 inches; irrigation well density (X8), 0-8 irrigation wells/ sq mi; and annual nitrogen fertilizer use (X9), 0-260 lbs of nitrogen/acre. Nitrate concentrations ranged from < 0.1 to 45 mg/L as nitrogen. Triazine herbicide concentrations were detected in samples from five of the six study areas in concentrations ranging from < 0.1 to 2.3 mg/L. Statistical tests indicated that there were significant differences in nitrate concentrations among the six study areas, while no significant differences in triazine herbicide concentrations were found. Concentrations of nitrate and triazine herbicide were significantly larger in more intensively irrigated areas. Preliminary correlations with the independent variables and nitrate concentrations indicated significant relations at the 95% confidence level with variables X2, X5, and X8. Correlations with triazine herbicide concentrations indicated significant relations with variables X2 , X3, X5, X6, and X8, and with nitrate concentrations (X10). By using a simple multiple regression technique, variables X5, X8, and X9 explained about 51% of the variation in nitrate concentrations. Variables X3

  7. Nitrate removal and denitrification in headwater agricultural streams of the Pacific Northwest

    EPA Science Inventory

    Headwater streams can serve as important sites for nitrogen (N) removal in watersheds. Here we examine the influence of agricultural streams on watershed N export in the Willamette River Basin of western Oregon, USA, a region with mixed agricultural, urban and forestry land uses...

  8. Selenium and nitrate removal from agricultural drainage using the AIWPS(R) technology

    SciTech Connect

    Green, F.B.; Lundquist, T.J.; Quinn, N.W.T.; Zarate, M.A.; Zubieta, I.X.; Oswald, W.J.

    2003-01-02

    Monthly Maximum Discharge Limits (MMDL) have been established for selenium in irrigation drainage by the State of California and the U.S. Environmental Protection Agency following observations of avian teratogenesis at the Kesterson Reservoir in the San Joaquin Valley of California. As a result of these and other adverse effects, farmers and drainage districts on the western side of the San Joaquin Valley must reduce selenium concentrations in irrigation, drainage discharged to the San Joaquin River. Drainage treatment will be required in the near future to meet existing MMDL and future Total Maximum Discharge Limits (TMDL) for the San Joaquin River. A 0.4-hectare Algal Bacterial Selenium Removal (ABSR) Facility was designed and constructed at the Panoche Drainage District in 1995 and 1996 using the Advanced Integrated Wastewater Pond Systems (R) or AIWPS (R) Technology. Each of two physically identical systems combined a Reduction Pond (RP) with a shallow, peripheral algal High Rate Pond (HRP). A Dissolved Air Flotation (DAF) unit and a slow sand filter were used to remove particulate selenium from the effluent of each system. The two systems were operated under different modes of operation and the bacterial substrate varied in each system. The rates of nitrate and selenium removal were compared. Microalgae were harvested using DAF and used as a carbon-rich substrate for nitrate- and selenate-reducing bacteria. Mass removals of total soluble selenium of 77 percent or greater were achieved over a three-year period. Nitrate and selenate were removed by assimilatory and dissimilatory bacterial reduction, and nitrate was also removed by algal assimilation. The final removal of particulate selenium is the focus of ongoing investigations. The removal of particulate selenium is expected to increase the overall removal of selenium to greater than 90 percent and would allow farmers and drainage districts to discharge irrigation drainage in compliance with regulatory

  9. Residence time, chemical and isotopic analysis of nitrate in the groundwater and surface water of a small agricultural watershed in the Coastal Plain, Bucks Branch, Sussex County, Delaware

    USGS Publications Warehouse

    Clune, John W.; Denver, Judith M.

    2012-01-01

    Nitrate is a common contaminant in groundwater and surface water throughout the Nation, and water-resource managers need more detailed small-scale watershed research to guide conservation efforts aimed at improving water quality. Concentrations of nitrate in Bucks Branch are among the highest in the state of Delaware and a scientific investigation was performed to provide water-quality information to assist with the management of agriculture and water resources. A combination of major-ion chemistry, nitrogen isotopic composition and age-dating techniques was used to estimate the residence time and provide a chemical and isotopic analysis of nitrate in the groundwater in the surficial aquifer of the Bucks Branch watershed in Sussex County, Delaware. The land use was more than 90 percent agricultural and most nitrogen inputs were from manure and fertilizer. The apparent median age of sampled groundwater is 18 years and the estimated residence time of groundwater contributing to the streamflow for the entire Bucks Branch watershed at the outlet is approximately 19 years. Concentrations of nitrate exceeded the U.S. Environmental Protection Agency drinking-water standard of 10 milligrams per liter (as nitrogen) in 60 percent of groundwater samples and 42 percent of surface-water samples. The overall geochemistry in the Bucks Branch watershed indicates that agriculture is the predominant source of nitrate contamination and the observed patterns in major-ion chemistry are similar to those observed in other studies on the Mid-Atlantic Coastal Plain. The pattern of enrichment in nitrogen and oxygen isotopes (δ15N and δ18O) of nitrate in groundwater and surface water indicates there is some loss of nitrate through denitrification, but this process is not sufficient to remove all of the nitrate from groundwater discharging to streams, and concentrations of nitrate in streams remain elevated.

  10. 21 CFR 181.33 - Sodium nitrate and potassium nitrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium nitrate and potassium nitrate. 181.33...-Sanctioned Food Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions issued by the U.S. Department of Agriculture for use as sources...

  11. 21 CFR 181.33 - Sodium nitrate and potassium nitrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium nitrate and potassium nitrate. 181.33...-Sanctioned Food Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions issued by the U.S. Department of Agriculture for use as sources...

  12. 21 CFR 181.33 - Sodium nitrate and potassium nitrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium nitrate and potassium nitrate. 181.33...-Sanctioned Food Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions issued by the U.S. Department of Agriculture for use as sources...

  13. Classification characteristics of multivariate analyses for groundwater chemistry in the nitrate contaminated area

    NASA Astrophysics Data System (ADS)

    Nakagawa, K.; Amano, H.

    2015-12-01

    Groundwater nitrate pollution in agricultural field is a common problem in many parts of the world. To design effective countermeasures for the pollution, understanding of contaminant transport and source identification will be in need. Classification of groundwater chemistry is useful tool to compare between water from different sources. In this study, results of 4 multivariate analyses for groundwater chemistry were compared. In the multivariate analyses, 277 sampling points data of major ion concentrations (Cl-, NO3-, SO42-, HCO3-, Na+, K+, Mg2+, Ca2+) were used (2011-2013). 4 multivariate analysis methods were as follows; 1) HCA (Hierarchical Cluster Analysis); Based on 8 major ion concentrations (8 dimensional 277 vectors), HCA was performed. 2) HCA with PCA (Principal Component Analysis); PCA was performed with major ion concentrations. Based on 2 principal components scores obtained from PCA (2 dimensional 277 vectors), HCA was performed. 3) HCA with SOM (Self Organized Map); SOM was performed with major ion concentrations. Obtained 84 reference vectors used for HCA (8 dimensional 84 vectors). 4) HCA, SOM with PCA; PCA was performed with major ion concentrations. Based on 2 principal component scores obtained from PCA, SOM was performed. Finally, HCA was performed with 80 reference vectors (2 dimensional 80 vectors). The number of clusters were fixed to 5, which was determined based on DBI (Davies-Bouldin Index) at the method 3). Broadly characteristics of each cluster is same among all multivariate analysis methods. According to this characteristics, 2 of 5 clusters show nitrate pollution, which are exceeding Japanese drinking water standards (10 mg/L). This 2 clusters can be distinguished by level of nitrate concentration. Other 3 clusters can also distinguished by level of major ion concentrations. Each cluster may be related to land use, because spatial distribution of sampling points shown by clusters congregate in specific locations. In the methods 1

  14. Agricultural intensification and changes in cultivated areas, 1970–2005

    PubMed Central

    Rudel, Thomas K.; Schneider, Laura; Uriarte, Maria; Turner, B. L.; DeFries, Ruth; Lawrence, Deborah; Geoghegan, Jacqueline; Hecht, Susanna; Ickowitz, Amy; Lambin, Eric F.; Birkenholtz, Trevor; Baptista, Sandra; Grau, Ricardo

    2009-01-01

    Does the intensification of agriculture reduce cultivated areas and, in so doing, spare some lands by concentrating production on other lands? Such sparing is important for many reasons, among them the enhanced abilities of released lands to sequester carbon and provide other environmental services. Difficulties measuring the extent of spared land make it impossible to investigate fully the hypothesized causal chain from agricultural intensification to declines in cultivated areas and then to increases in spared land. We analyze the historical circumstances in which rising yields have been accompanied by declines in cultivated areas, thereby leading to land-sparing. We use national-level United Nations Food and Agricultural Organization data on trends in cropland from 1970–2005, with particular emphasis on the 1990–2005 period, for 10 major crop types. Cropland has increased more slowly than population during this period, but paired increases in yields and declines in cropland occurred infrequently, both globally and nationally. Agricultural intensification was not generally accompanied by decline or stasis in cropland area at a national scale during this time period, except in countries with grain imports and conservation set-aside programs. Future projections of cropland abandonment and ensuing environmental services cannot be assumed without explicit policy intervention. PMID:19955435

  15. Determination of atmospheric nitrate particulate size distribution and dry deposition velocity for three distinct areas.

    PubMed

    Yang, Hsi-Hsien; Hsieh, Lien-Te; Cheng, Shih-Kai

    2005-09-01

    In this study, both atmospheric particulates and dry deposited particulates were collected at a highway intersection, coastal location and suburban area in Taichung, Taiwan for the characterization of nitrate containing particulates (NCPs) in size distribution and dynamic properties. Collected particulates were placed in contact with nitron (C20H16N4) to form distinctive products of NCPs, which were examined by a SEM. For total atmospheric particulates, the sum of NCP and non-nitrate containing particulate (NNCP), the average shape factor values are 1.69, 1.49, and 1.36 for the highway intersection, coastal area and suburban area, respectively. The calculated shape factors show no significant differences with sizes. Dry deposition fluxes and atmospheric concentrations at various size ranges were estimated. The mass distributed in fine particle range (areas, respectively. The average dry deposition velocities (Vds) of total particulate are 2.5, 1.5, and 1.2 cm s(-1) for highway intersection, coastal area, and suburban area, respectively. The highest Vd was observed from samples taken at highway intersection, suggesting that dust resuspension and particulates from vehicles in the ambient air is of great significance. The Vds of total particulates range over three orders of magnitude for size ranges from 0.32 to 18 microm. The value of Vd increases with the diameter of particles significantly.

  16. Agricultural and Ranching area, Rio Sao Francisco, Brazil

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This agricultural and Ranching area, Rio Sao Francisco, Brazil (13.0S, 43.5W) has been under study for several years. See scene STS-31-92-045 for comparison. This area has many small single family subsistence farms, large square and rectangular commercial farms and pastures for livestock grazing. Over the several years of observation, the number and size of farms has increased and center-pivot, swing-arm irrigation systems have been installed.

  17. Case study of groundwater pollution in a critical area of the Southern-Friuli exposed to agricultural and landfill pressures.

    PubMed

    Adami, G; Siviero, P; Barbieri, P; Piselli, S; Reisenhofer, E

    2001-01-01

    Groundwater of the Southern-Friuli displays high levels of agricultural pollutants, such as nitrates and triazinic herbicides not only in the surficial layers, but also in the deeper ones, below 150 m. Some wells of the district of Gonars was monitored. The examined waters, used for irrigation but also for drinkable use, are exposed to environmental risk due to both agricultural practices and presence of many waste disposal sites. Heavy metals, nitrates and triazinic herbicides were measured in samples taken at four wells in three periods having different rain conditions. We found that groundwater quality is affected mainly by agricultural practices: nitrates and triazines are present at levels very near as well as superior to the maximum concentration allowable by Italian law. These agricultural contaminants have similar levels at all sampled sites: no difference was detected between dry periods and rain ones. Heavy metal contents are negligible in all cases; this fact suggests that ion-exchange, sorbing and complexing properties of the soils hinder the way of the metal leachates towards underlying groundwater. Zinc constitutes an exception; it is found at levels near or superior to the maximum allowable concentration (CMA), and the highest contents are observed in rain periods; different sites display different zinc levels, suggesting that this metal could have various point sources. Nitrates fertilisers were found in all sites at similar levels, very near to CMA (50 mg/L). Triazines are specific herbicides for corn growing, highly diffused here: their use in recent years is forbidden by Italian law, but the presence in groundwater of parent triazines and metabolites is a persistent problem of this area. The Italian law indicates a CMA of 0.10 microgram/L for the sum of atrazine and desethylatrazine, but we found that desethylatrazine by itself exceeds largely CMA in all sites.

  18. Antecedent conditions, hydrological connectivity and anthropogenic inputs: Factors affecting nitrate and phosphorus transfers to agricultural headwater streams.

    PubMed

    Outram, Faye N; Cooper, Richard J; Sünnenberg, Gisela; Hiscock, Kevin M; Lovett, Andrew A

    2016-03-01

    This paper examines relationships between rainfall-runoff, catchment connectivity, antecedent moisture conditions and fertiliser application with nitrate-N and total phosphorus (TP) fluxes in an arable headwater catchment over three hydrological years (2012-2014). Annual precipitation totals did not vary substantially between years, yet the timing of rainfall strongly influenced runoff generation and subsequent nitrate-N and TP fluxes. The greatest nitrate-N (>250 kg N day(-1)) and TP (>10 kg TP day(-1)) fluxes only occurred when shallow groundwater was within 0.6m of the ground surface and runoff coefficients were greater than 0.1. These thresholds were reached less frequently in 2012 due to drought recovery resulting in lower annual nitrate-N (7.4 kg N ha(-1)) and TP (0.12 kg P ha(-1)) fluxes in comparison with 2013 (15.1 kg N ha(-1); 0.21 kg P ha(-1)). The wet winter of 2013 with elevated shallow groundwater levels led to more frequent activation of sub-surface pathways and tile drain flow. Throughout the period, dry antecedent conditions had a temporary effect in elevating TP loads. Evidence of TP source exhaustion after consecutive storm events can be attributed to the repeated depletion of temporarily connected critical source areas to the river network via impermeable road surfaces. Fertiliser application varied considerably across three years due to differences in crop rotation between farms, with annual N and P fertiliser inputs varying by up to 21% and 41%, respectively. Proportional reductions in annual riverine nitrate-N and TP loadings were not observed at the sub-catchment outlet as loadings were largely influenced by annual runoff. Nitrate loadings were slightly higher during fertiliser application, but there was little relationship between P fertiliser application and riverine TP load. These data indicate that this intensive arable catchment may be in a state of biogeochemical stationarity, whereby legacy stores of nutrients buffer against changes

  19. Metolachlor metabolite (MESA) reveals agricultural nitrate-N fate and transport in Choptank River watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen from agricultural activities contributes to the hypoxic zones and severe declines in water quality in the Gulf of Mexico and the Chesapeake Bay. The Federal Clean Water Act requires nitrogen load reductions to restore the integrity of these important waterways. Tools are needed to track t...

  20. Nitrate sinks in perennial vegetation filter strips in the toeslopes of agricultural watersheds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Integration of perennial filter strips (PFS) into the toeslope of agricultural watersheds may decrease downstream NO3 losses, especially if subsurface flow interacts with the rooting zone of the perennial vegetation. However, the long-term effectiveness of NO3 removal depends on the relative importa...

  1. Chemometric evaluation of nitrate contamination in the groundwater of a hard rock area in Dharapuram, south India

    NASA Astrophysics Data System (ADS)

    Sajil Kumar, P. J.; Jegathambal, P.; James, E. J.

    2014-12-01

    This paper presents the results of investigations on groundwater nitrate contamination in the Dharapuram area of Tamil Nadu in south India as a primary step to initiate denitrification. Groundwater samples were collected from 26 selected locations during the pre-monsoon season in July 2010 and analysed for nitrate and other water quality parameters. Two important water types were identified, viz. Ca-Na-HCO3 and mixed Ca-Mg-Cl. It is found that the majority of samples possess high nitrate concentration; 57 % of samples exceeded the permissible limit of Indian (45 mg/L) and WHO (50 mg/L) drinking water standard. Spatial distribution map of NO3 suggested that major contamination was observed in the SW and NW parts of the study area. This result was in agreement with the corresponding land-use pattern in this study area. Denitrification process at greater depths was evident from the negative correlation between NO3 and well depth. The sources and controlling factors of high nitrate were investigated using cross plots of NO3 with other selected hydrochemical parameters. Positive correlation for NO3 was observed with EC, K, Cl and SO4. This analysis was capable of differentiating the various sources of nitrate in groundwater. The major sources of nitrate contamination are identified as areas of high fertilizer application, sewages and animal waste dumping yards. Regulation of these pollutant sources with appropriate and cost-effective denitrification process can restore the water quality in this area.

  2. Concentration-Discharge Patterns Revealed from High Resolution Nitrate Measurements in Agricultural Landscapes

    NASA Astrophysics Data System (ADS)

    Boland, S. J.; Basu, N. B.

    2012-12-01

    Riverine export of nutrients is a major component of nutrient cycles, particularly with respect to nitrogen; ~ 25 percent of terrestrially applied nitrogen (N) is removed via riverine export. Understanding the patterns in N export during a storm event is critical for developing a conceptual model of the dominant processes and pathways of N transformation, and designing appropriate management strategies to mitigate N pollution in streams and receiving water bodies. Most studies however, are limited by the lack of high-resolution water quality data to elucidate these pathways and mechanisms. We explored concentration-discharge relationships using high-resolution (15 minute) discharge (Q) and nitrate concentration (C) data (measured using an in-situ Nitratax Sonde) at multiple nested scales (from 151.3 km2 to 8900 km2) in two watersheds in Iowa: Clear Creek Watershed and the Raccoon River watershed. Three distinct regimes of nitrate transport were revealed: (1) a linear regime in which C increases with increasing Q, (2) a saturation regime in which C remains constant against increasing Q, and (3) a dilution regime in which concentration decreases as Q increases. The tight clustering of the data along these patterns is indicative of emergent behavior in such human-dominated systems. All three regimes were apparent in the Raccoon River Watershed, while only the saturation and dilution regimes were apparent in the Clear Creek Watershed. We hypothesize that surface flow is dominant in the Clear Creek Watershed leading to a saturation/dilution regimes, while subsurface flow is dominant in the more heavily tile-drained Raccoon River Watershed, leading to the occurrence of all three regimes. A parsimonious model was developed to test the hypothesis and develop C-Q patterns as a function of the partitioning of flow through the different pathways.

  3. Relationship of Stream Flow Rates to Nitrate-N and Pesticide Attenuation in an Agriculturally Impacted First-Order Riparian System, Inner Coastal Plain, Maryland

    NASA Astrophysics Data System (ADS)

    Angier, J. T.; McCarty, G. W.; Rice, C. P.; Prestegaard, K. L.

    2002-05-01

    A valuable function of riparian zones in agricultural settings is the mitigation of contaminants applied to nearby crop fields. This riparian function can be highly variable, both spatially and temporally, within a single ecosystem. Some of this variability may result from hydrological differences, which in turn are influenced by meteorological changes and local geomorphology. The site of this study is part of the USDA-ARS Beltsville Agricultural Research Center in Maryland. It consists of a small, first-order stream and associated riparian zone. The riparian zone receives nutrient and pesticide loads from the neighboring agricultural field. The stream is instrumented with five monitoring/sampling stations for evaluating stream flows and water quality along stream length intervals. Approximately 170 piezometers have been instrumented throughout the site. Three full years of data have been compiled and analyzed. The exportability of some contaminants (nitrate-N and Metolachlor metabolites) appears to be dependent upon stream flow conditions. Higher stream baseflows are strongly linked to higher stream contaminant loads. In the case of nitrate-N, higher stream baseflows tend to yield higher stream nitrate concentrations as well as higher nitrate fluxes, particularly in the downstream sections. There are seasonal patterns in stream nitrate fluxes that suggest in-stream (hyporheic) nitrate processing occurs. Evidence for loss of nitrate within the stream is especially apparent in late Autumn and early Winter, when decaying leaves collect in pools along the stream channel; there is often a downstream increase in stream flow, but a loss of nitrate flux. There is also evidence for stream N processing during Summer. Groundwater quality and delivery patterns vary spatially, and in response to changes in climate, affecting the stream water characteristics as well. Stream nitrate-N and pesticide loads increase with higher stream baseflow conditions because there is more rapid

  4. Using lumped modelling for providing simple metrics and associated uncertainties of catchment response to agricultural-derived nitrates pollutions

    NASA Astrophysics Data System (ADS)

    RUIZ, L.; Fovet, O.; Faucheux, M.; Molenat, J.; Sekhar, M.; Aquilina, L.; Gascuel-odoux, C.

    2013-12-01

    The development of simple and easily accessible metrics is required for characterizing and comparing catchment response to external forcings (climate or anthropogenic) and for managing water resources. The hydrological and geochemical signatures in the stream represent the integration of the various processes controlling this response. The complexity of these signatures over several time scales from sub-daily to several decades [Kirchner et al., 2001] makes their deconvolution very difficult. A large range of modeling approaches intent to represent this complexity by accounting for the spatial and/or temporal variability of the processes involved. However, simple metrics are not easily retrieved from these approaches, mostly because of over-parametrization issues. We hypothesize that to obtain relevant metrics, we need to use models that are able to simulate the observed variability of river signatures at different time scales, while being as parsimonious as possible. The lumped model ETNA (modified from[Ruiz et al., 2002]) is able to simulate adequately the seasonal and inter-annual patterns of stream NO3 concentration. Shallow groundwater is represented by two linear stores with double porosity and riparian processes are represented by a constant nitrogen removal function. Our objective was to identify simple metrics of catchment response by calibrating this lumped model on two paired agricultural catchments where both N inputs and outputs were monitored for a period of 20 years. These catchments, belonging to ORE AgrHys, although underlain by the same granitic bedrock are displaying contrasted chemical signatures. The model was able to simulate the two contrasted observed patterns in stream and groundwater, both on hydrology and chemistry, and at the seasonal and pluri-annual scales. It was also compatible with the expected trends of nitrate concentration since 1960. The output variables of the model were used to compute the nitrate residence time in both the

  5. Topography Mediates the Influence of Cover Crops on Soil Nitrate Levels in Row Crop Agricultural Systems.

    PubMed

    Ladoni, Moslem; Kravchenko, Alexandra N; Robertson, G Phillip

    2015-01-01

    Supplying adequate amounts of soil N for plant growth during the growing season and across large agricultural fields is a challenge for conservational agricultural systems with cover crops. Knowledge about cover crop effects on N comes mostly from small, flat research plots and performance of cover crops across topographically diverse agricultural land is poorly understood. Our objective was to assess effects of both leguminous (red clover) and non-leguminous (winter rye) cover crops on potentially mineralizable N (PMN) and [Formula: see text] levels across a topographically diverse landscape. We studied conventional, low-input, and organic managements in corn-soybean-wheat rotation. The rotations of low-input and organic managements included rye and red clover cover crops. The managements were implemented in twenty large undulating fields in Southwest Michigan starting from 2006. The data collection and analysis were conducted during three growing seasons of 2011, 2012 and 2013. Observational micro-plots with and without cover crops were laid within each field on three contrasting topographical positions of depression, slope and summit. Soil samples were collected 4-5 times during each growing season and analyzed for [Formula: see text] and PMN. The results showed that all three managements were similar in their temporal and spatial distributions of NO3-N. Red clover cover crop increased [Formula: see text] by 35% on depression, 20% on slope and 32% on summit positions. Rye cover crop had a significant 15% negative effect on [Formula: see text] in topographical depressions but not in slope and summit positions. The magnitude of the cover crop effects on soil mineral nitrogen across topographically diverse fields was associated with the amount of cover crop growth and residue production. The results emphasize the potential environmental and economic benefits that can be generated by implementing site-specific topography-driven cover crop management in row

  6. Topography Mediates the Influence of Cover Crops on Soil Nitrate Levels in Row Crop Agricultural Systems.

    PubMed

    Ladoni, Moslem; Kravchenko, Alexandra N; Robertson, G Phillip

    2015-01-01

    Supplying adequate amounts of soil N for plant growth during the growing season and across large agricultural fields is a challenge for conservational agricultural systems with cover crops. Knowledge about cover crop effects on N comes mostly from small, flat research plots and performance of cover crops across topographically diverse agricultural land is poorly understood. Our objective was to assess effects of both leguminous (red clover) and non-leguminous (winter rye) cover crops on potentially mineralizable N (PMN) and [Formula: see text] levels across a topographically diverse landscape. We studied conventional, low-input, and organic managements in corn-soybean-wheat rotation. The rotations of low-input and organic managements included rye and red clover cover crops. The managements were implemented in twenty large undulating fields in Southwest Michigan starting from 2006. The data collection and analysis were conducted during three growing seasons of 2011, 2012 and 2013. Observational micro-plots with and without cover crops were laid within each field on three contrasting topographical positions of depression, slope and summit. Soil samples were collected 4-5 times during each growing season and analyzed for [Formula: see text] and PMN. The results showed that all three managements were similar in their temporal and spatial distributions of NO3-N. Red clover cover crop increased [Formula: see text] by 35% on depression, 20% on slope and 32% on summit positions. Rye cover crop had a significant 15% negative effect on [Formula: see text] in topographical depressions but not in slope and summit positions. The magnitude of the cover crop effects on soil mineral nitrogen across topographically diverse fields was associated with the amount of cover crop growth and residue production. The results emphasize the potential environmental and economic benefits that can be generated by implementing site-specific topography-driven cover crop management in row

  7. Topography Mediates the Influence of Cover Crops on Soil Nitrate Levels in Row Crop Agricultural Systems

    PubMed Central

    Ladoni, Moslem; Kravchenko, Alexandra N.; Robertson, G. Phillip

    2015-01-01

    Supplying adequate amounts of soil N for plant growth during the growing season and across large agricultural fields is a challenge for conservational agricultural systems with cover crops. Knowledge about cover crop effects on N comes mostly from small, flat research plots and performance of cover crops across topographically diverse agricultural land is poorly understood. Our objective was to assess effects of both leguminous (red clover) and non-leguminous (winter rye) cover crops on potentially mineralizable N (PMN) and NO3--N levels across a topographically diverse landscape. We studied conventional, low-input, and organic managements in corn-soybean-wheat rotation. The rotations of low-input and organic managements included rye and red clover cover crops. The managements were implemented in twenty large undulating fields in Southwest Michigan starting from 2006. The data collection and analysis were conducted during three growing seasons of 2011, 2012 and 2013. Observational micro-plots with and without cover crops were laid within each field on three contrasting topographical positions of depression, slope and summit. Soil samples were collected 4–5 times during each growing season and analyzed for NO3--N and PMN. The results showed that all three managements were similar in their temporal and spatial distributions of NO3—N. Red clover cover crop increased NO3--N by 35% on depression, 20% on slope and 32% on summit positions. Rye cover crop had a significant 15% negative effect on NO3--N in topographical depressions but not in slope and summit positions. The magnitude of the cover crop effects on soil mineral nitrogen across topographically diverse fields was associated with the amount of cover crop growth and residue production. The results emphasize the potential environmental and economic benefits that can be generated by implementing site-specific topography-driven cover crop management in row-crop agricultural systems. PMID:26600462

  8. Evaluation of the impact of various agricultural practices on nitrate leaching under the root zone of potato and sugar beet using the STICS soil-crop model.

    PubMed

    Jégo, G; Martínez, M; Antigüedad, I; Launay, M; Sanchez-Pérez, J M; Justes, E

    2008-05-15

    The quaternary aquifer of Vitoria-Gasteiz (Basque Country, Northern Spain) is characterised by a shallow water table mainly fed by drainage water, and thus constitutes a vulnerable zone in regards to nitrate pollution. Field studies were performed with a potato crop in 1993 and a sugar beet crop in 2002 to evaluate their impact on nitrate leaching. The overall predictive quality of the STICS soil-crop model was first evaluated using field data and then the model was used to analyze dynamically the impacts of different crop management practices on nitrate leaching. The model was evaluated (i) on soil nitrate concentrations at different depths and (ii) on crop yields. The simulated values proved to be in satisfactory agreement with measured values. Nitrate leaching was more pronounced with the potato crop than with the sugar beet experiment due to i) greater precipitation, ii) lower N uptake of the potato crop due to shallow root depth, and iii) a shorter period of growth. The potato experiment showed that excessive irrigation could significantly increase nitrate leaching by increasing both drainage and nitrate concentrations. The different levels of N-fertilization examined in the sugar beet study had no notable effects on nitrate leaching due to its high N uptake capacity. Complementary virtual experiments were carried out using the STICS model. Our study confirmed that in vulnerable zones agricultural practices must be adjusted, that is to say: 1) N-fertilizer should not be applied in autumn before winter crops; 2) crops with low N uptake capacity (e.g. potatoes) should be avoided or should be preceded and followed by nitrogen catch crops or cover crops; 3) the nitrate concentration of irrigation water should be taken into account in calculation of the N-fertilization rate, and 4) N-fertilization must be precisely adjusted in particular for potato crops.

  9. Impact of agriculture and land use on nitrate contamination in groundwater and running waters in central-west Poland.

    PubMed

    Lawniczak, Agnieszka Ewa; Zbierska, Janina; Nowak, Bogumił; Achtenberg, Krzysztof; Grześkowiak, Artur; Kanas, Krzysztof

    2016-03-01

    Protected areas due to their long-term protection are expected to be characterized by good water quality. However, in catchments where arable fields dominate, the impact of agriculture on water pollution is still problematic. In Poland, recently, the fertilization level has decreased, mostly for economic reasons. However, this applies primarily to phosphorus and potassium. In order to evaluate the impact of agriculture on water quality in a protected area with a high proportion of arable fields in the aspect of level and type of fertilization, complex monitoring has been applied. The present study was carried out in Wielkopolska National Park and its buffer zone, which are protected under Natura 2000 as Special Areas of Conservation and Special Protection Areas. The aim of the study were (1) to assess the impact of agriculture, with special attention on fertilization, on groundwater, and running water quality and (2) to designate priority areas for implementing nitrogen reduction measures in special attention on protected areas. In our study, high nitrogen concentrations in groundwater and surface waters were detected in the agricultural catchments. The results demonstrate that in the watersheds dominated by arable fields, high nitrogen concentrations in groundwater were measured in comparison to forestry catchments, where high ammonium concentrations were observed. The highest nitrogen concentrations were noted in spring after winter freezing, with a small cover of vegetation, and in the areas with a high level of nitrogen application. In the studied areas, both in the park and its buffer zone, unfavorable N:P and N:K ratios in supplied nutrients were detected. Severe shortage of phosphorus and potassium in applied fertilizers is one of the major factors causing leaching of nitrogen due to limited possibilities of its consumption by plants. PMID:26887311

  10. Impact of agriculture and land use on nitrate contamination in groundwater and running waters in central-west Poland.

    PubMed

    Lawniczak, Agnieszka Ewa; Zbierska, Janina; Nowak, Bogumił; Achtenberg, Krzysztof; Grześkowiak, Artur; Kanas, Krzysztof

    2016-03-01

    Protected areas due to their long-term protection are expected to be characterized by good water quality. However, in catchments where arable fields dominate, the impact of agriculture on water pollution is still problematic. In Poland, recently, the fertilization level has decreased, mostly for economic reasons. However, this applies primarily to phosphorus and potassium. In order to evaluate the impact of agriculture on water quality in a protected area with a high proportion of arable fields in the aspect of level and type of fertilization, complex monitoring has been applied. The present study was carried out in Wielkopolska National Park and its buffer zone, which are protected under Natura 2000 as Special Areas of Conservation and Special Protection Areas. The aim of the study were (1) to assess the impact of agriculture, with special attention on fertilization, on groundwater, and running water quality and (2) to designate priority areas for implementing nitrogen reduction measures in special attention on protected areas. In our study, high nitrogen concentrations in groundwater and surface waters were detected in the agricultural catchments. The results demonstrate that in the watersheds dominated by arable fields, high nitrogen concentrations in groundwater were measured in comparison to forestry catchments, where high ammonium concentrations were observed. The highest nitrogen concentrations were noted in spring after winter freezing, with a small cover of vegetation, and in the areas with a high level of nitrogen application. In the studied areas, both in the park and its buffer zone, unfavorable N:P and N:K ratios in supplied nutrients were detected. Severe shortage of phosphorus and potassium in applied fertilizers is one of the major factors causing leaching of nitrogen due to limited possibilities of its consumption by plants.

  11. Nitrate-nitrogen losses through subsurface drainage under various agricultural land covers.

    PubMed

    Qi, Zhiming; Helmers, Matthew J; Christianson, Reid D; Pederson, Carl H

    2011-01-01

    Nitrate-nitrogen (NO₃-N) loading to surface water bodies from subsurface drainage is an environmental concern in the midwestern United States. The objective of this study was to investigate the effect of various land covers on NO₃-N loss through subsurface drainage. Land-cover treatments included (i) conventional corn ( L.) (C) and soybean [ (L.) Merr.] (S); (ii) winter rye ( L.) cover crop before corn (rC) and before soybean (rS); (iii) kura clover ( M. Bieb.) as a living mulch for corn (kC); and (iv) perennial forage of orchardgrass ( L.) mixed with clovers (PF). In spring, total N uptake by aboveground biomass of rye in rC, rye in rS, kura clover in kC, and grasses in PF were 14.2, 31.8, 87.0, and 46.3 kg N ha, respectively. Effect of land covers on subsurface drainage was not significant. The NO₃-N loss was significantly lower for kC and PF than C and S treatments (p < 0.05); rye cover crop did not reduce NO₃-N loss, but NO₃-N concentration was significantly reduced in rC during March to June and in rS during July to November (p < 0.05). Moreover, the increase of soil NO₃-N from early to late spring in rS was significantly lower than the S treatment (p < 0.05). This study suggests that kC and PF are effective in reducing NO₃-N loss, but these systems could lead to concerns relative to grain yield loss and change in farming practices. Management strategies for kC need further study to achieve reasonable corn yield. The effectiveness of rye cover crop on NO-N loss reduction needs further investigation under conditions of different N rates, wider weather patterns, and fall tillage.

  12. Nitrate in groundwater and water sources used by riparian trees in an agricultural watershed: A chemical and isotopic investigation in southern Minnesota

    USGS Publications Warehouse

    Komor, S.C.; Magner, J.A.

    1996-01-01

    This study evaluates processes that affect nitrate concentrations in groundwater beneath riparian zones in an agricultural watershed. Nitrate pathways in the upper 2 m of groundwater were investigated beneath wooded and grass-shrub riparian zones next to cultivated fields. Because trees can be important components of the overall nitrate pathway in wooded riparian zones, water sources used by riparian trees and possible effects of trees on nitrate concentrations in groundwater were also investigated. Average nitrate concentrations in shallow groundwater beneath the cultivated fields were 5.5 mg/L upgradient of the wooded riparian zone and 3.5 mg/L upgradient of the grass-shrub zone. Shallow groundwater beneath the fields passed through the riparian zones and discharged into streams that had average nitrate concentrations of 8.5 mg/L (as N). Lateral variations of ??D values in groundwater showed that mixing among different water sources occurred beneath the riparian zones. In the wooded riparian zone, nitrate concentrations in shallow groundwater were diluted by upwelling, nitrate- poor, deep groundwater. Upwelling deep groundwater contained ammonium with a ??15N of 5??? that upon nitrification and mixing with nitrate in shallow groundwater caused nitrate ??15N values in shallow groundwater to decrease by as much as 19.5???. Stream water penetrated laterally beneath the wooded riparian zone as far as 19 m from the stream's edge and beneath the grass- shrub zone as far as 27 m from the stream's edge. Nitrate concentrations in shallow groundwater immediately upgradient of where it mixed with stream water averaged 0.4 mg/L in the wooded riparian zone and 0.8 mg/L near the grass-shrub riparian zone. Nitrate concentrations increased toward the streams because of mixing with nitrate-rich stream water. Because nitrate concentrations were larger in stream water than shallow groundwater, concentrated nitrate in the streams cannot have come from shallow groundwater at these

  13. Nitrate in ground water and water sources used by riparian trees in an agricultural watershed: A chemical and isotopic investigation in southern Minnesota

    USGS Publications Warehouse

    Komor, Stephen C.; Magner, J.

    1996-01-01

    This study evaluates processes that affect nitrate concentrations in groundwater beneath riparian zones in an agricultural watershed. Nitrate pathways in the upper 2 m of groundwater were investigated beneath wooded and grass-shrub riparian zones next to cultivated fields. Because trees can be important components of the overall nitrate pathway in wooded riparian zones, water sources used by riparian trees and possible effects of trees on nitrate concentrations in groundwater were also investigated. Average nitrate concentrations in shallow groundwater beneath the cultivated fields were 5.5 mg/L upgradient of the wooded riparian zone and 3.5 mg/L upgradient of the grass-shrub zone. Shallow groundwater beneath the fields passed through the riparian zones and discharged into streams that had average nitrate concentrations of 8.5 mg/L (as N). Lateral variations of δD values in groundwater showed that mixing among different water sources occurred beneath the riparian zones. In the wooded riparian zone, nitrate concentrations in shallow groundwater were diluted by upwelling, nitrate-poor, deep groundwater. Upwelling deep groundwater contained ammonium with a δ15N of 5‰ that upon nitrification and mixing with nitrate in shallow groundwater caused nitrate δ15N values in shallow groundwater to decrease by as much as 19.5‰. Stream water penetrated laterally beneath the wooded riparian zone as far as 19 m from the stream's edge and beneath the grass-shrub zone as far as 27 m from the stream's edge. Nitrate concentrations in shallow groundwater immediately upgradient of where it mixed with stream water averaged 0.4 mg/L in the wooded riparian zone and 0.8 mg/L near the grass-shrub riparian zone. Nitrate concentrations increased toward the streams because of mixing with nitrate-rich stream water. Because nitrate concentrations were larger in stream water than shallow groundwater, concentrated nitrate in the streams cannot have come from shallow groundwater at these

  14. Nitrate contamination in groundwater of some rural areas of Rajasthan, India.

    PubMed

    Suthar, Surindra; Bishnoi, Preeti; Singh, Sushma; Mutiyar, Pravin K; Nema, Arvind K; Patil, Nagraj S

    2009-11-15

    Efforts were made to evaluate the level of nitrate in some agro-economy based rural habitations of northern Rajasthan, India. A total of 64 groundwater samples from 21 different villages/sub-villages of district Sri Ganganagar, India were collected and analyzed for nitrate (as NO(3)(-)), sulphate (as SO(4)(2-)) and few other parameters. NO(3)(-) level in groundwater was 7.10-82.0 mg l(-1) for individual samples. But average NO(3)(-) for total samples was 60.6+/-33.6 (SD) mg l(-1), which indicates the non-suitability of groundwater for drinking purposes, if BIS permissible limit (22.6 mg l(-1)) is considered as reference level. SO(4)(2-) ranged form 28.6 to 660.3 mg l(-1) in this area. The regression analysis indicates the difference sources for NO(3)(-) and SO(4)(2-) contamination in different regions rather than a common source. The point and non-point sources of NO(3)(-) and SO(4)(2-) in groundwater of this region may be N-fertilizer, sewerage, animal waste, organic manure, geology of sub-surface soil layers, pit latrines, etc. Results thus indicated that groundwater of this part of the State is severely polluted due to anthropogenic activities. The continuous consumption of such water may pose serious health hazardous in local residents.

  15. Nitrate removal from agricultural drainage ditch sediments with amendments of organic carbon: Potential for an innovative best management practice

    USGS Publications Warehouse

    Faust, Derek R.; Kröger, Robert; Miranda, Leandro E.; Rush, Scott A.

    2016-01-01

    Agricultural fertilizer applications have resulted in loading of nutrients to agricultural drainage ditches in the Lower Mississippi Alluvial Valley. The purpose of this study was to determine effects of dissolved organic carbon (DOC) and particulate organic carbon (POC) amendments on nitrate-nitrogen (NO3−-N) removal from overlying water, pore water, and sediment of an agricultural drainage ditch. Two experiments were conducted. In experiment 1, control (i.e., no amendment), DOC, and POC treatments were applied in laboratory microcosms for time intervals of 3, 7, 14, and 28 days. In experiment 2, control, DOC, and POC treatments were applied in microcosms at C/N ratios of 5:1, 10:1, 15:1, and 20:1. There were statistically significant effects of organic carbon amendments in experiment 1 (F2,71 = 27.1, P < 0.001) and experiment 2 (F2,53 = 39.1, P < 0.001), time (F1,71 = 14.5, P < 0.001) in experiment 1, and C/N ratio (F1,53 = 36.5, P < 0.001) in experiment 2. NO3−-N removal varied from 60 to 100 % in overlying water among all treatments. The lowest NO3−-N removals in experiment 1 were observed in the control at 14 and 28 days, which were significantly less than in DOC and POC 14- and 28-day treatments. In experiment 2, significantly less NO3−-N was removed in overlying water of the control compared to DOC and POC treatments at all C/N ratios. Amendments of DOC and POC made to drainage ditch sediment: (1) increased NO3−-N removal, especially over longer time intervals (14 to 28 days); (2) increased NO3−-N removal, regardless of C/N ratio; and (3) NO3−-N removal was best at a 5:1 C/N ratio. This study provides support for continued investigation on the use of organic carbon amendments as a best management practice for NO3−-N removal in agricultural drainage ditches.

  16. Identification of potential source areas for elevated PM2.5, nitrate and sulfate concentrations

    NASA Astrophysics Data System (ADS)

    Heo, Jongbae; McGinnis, Jerome E.; de Foy, Benjamin; Schauer, James J.

    2013-06-01

    Extreme events or episodes of ambient fine particulate matter (PM2.5), in which daily mass concentrations are substantially higher than annual averages, have been frequently observed in southern Wisconsin, US. Determining the cause of events has been a great challenge to local governments responsible for protecting public health and complying with the 24-h PM2.5 standard. This study analyzed air parcel movements originating from emission source areas, and trends in PM2.5 concentrations in order to determine the important factors involved in elevated PM2.5 episodes in the region. A single backward trajectory analysis coupled with PM2.5 concentrations observed at Federal Reference Method Network (FRM) sites in Madison, Milwaukee and Waukesha; and nitrate and sulfate concentrations monitored at a Chemical Speciation Network (CSN) site in Milwaukee, Wisconsin, from 2002 to 2010 were examined. The PM2.5 concentrations from the FRM showed the total PM2.5 mass during the episodes were higher in Madison than in Milwaukee and Waukesha, while annual average concentrations were lower in Madison. However, the temporal trend in frequency of elevated PM2.5 episodes was remarkably similar across sites during the entire study period and high frequency episodes occurring from 2005 to 2007. Residence time analysis of backward trajectories calculated for all recorded data indicated episode changes were mainly driven by year-to-year variations of air mass movements originating in high emissions areas. Potential Source Contribution Function (PSCF) results showed the extreme events of PM2.5 occurred during times when trajectories passed over ammonia emissions hotspots as well as large stationary emissions. Enhanced nitrate and sulfate concentrations which were the major episode components were strongly influenced by air masses trajectories originating from the Ohio River Valley and adjacent states.

  17. Identification of the origin of salts in an agricultural area of SE Spain

    NASA Astrophysics Data System (ADS)

    Acosta, Jose A.; Faz, Angel; Kalbitz, Karsten; Jansen, Boris; Silvia, Martinez-Martinez

    2010-05-01

    In spite of soil salinity having been widely studied in many part of the world, origin of salinity has not been addresses in detail in some of the most productive agricultural areas of Europe (e.g. southeast of Spain). According to the European Commission, salinization affects about 1 to 3 million ha of the area of the European Union and Candidate Countries. In Europe, most of the salt-affected land surfaces are concentrated in the Mediterranean basin. In Spain, about 3% of the 3.5 million hectares of irrigated land are severely affected by salts and another 15% is at serious risk of imminent salinization. Due to the limited water resources in southeast of Spain, water with marginal quality is used for irrigation. The use of this water has led to degradation, reduction of the land's production capacity and soil salinization. The main aim of the present study was to identify the origin of the salts involved in such salinization, using classical and multivariable statistical techniques. In order to achieve this objective, surface soil samples were collected in January and July 2009 at 48 sites located in a representative lemon production area close to City of Murcia, covering a surface area of 44 km2. Soil pH, electrical conductivity, ionic composition, total organic matter, equivalent calcium carbonate, cation exchange capacity and particle size distribution were determined. The Pearson correlation coefficient, r, was used to measure the relationship between two quantitative variables and principal components analysis was used to study the correlations among anions and cations and their grouping into several factors. Results indicated that the high electrical conductivity found in the study area indeed comes from poor quality irrigation water used for agriculture. Anions and cations responsible of the salinity were chlorides, sulphates, calcium, magnesium and sodium. Mismanagement of water and traditional irrigation system resulted in salt build-up in the soil

  18. Examination of nitrate concentration, loading and isotope dynamics in subsurface drainage under standard agricultural cropping in Atlantic Canada.

    PubMed

    Smith, E L; Kellman, L M

    2011-11-01

    Intensive agricultural farming practices have the potential to cause high levels of nitrate-nitrogen (NO(3)(-)-N) to be released from tile drainage systems. A better understanding of the temporal dynamics of NO(3)(-)-N loading, δ(15)N and δ(18)O from standard drainage systems is needed, in order to improve our understanding of NO(3)(-)-N transport and transformation processes; particularly, with regards to the imperfectly drained agricultural soils found within Atlantic Canada. Three conventional subsurface drainage plots (48 × 48 m) placed at a 0.80 m soil depth were monitored over a seven month period on sandy loam soil in Onslow, Nova Scotia. Each plot received similar applications of both organic and inorganic fertilizer. Water samples were obtained and analyzed for NO(3)(-)-N concentrations and isotopic signatures of δ(15)N and δ(18)O for NO(3)(-)-N. Maximum NO(3)(-)-N loads were observed in the winter and fall, when both discharge and concentration of the NO(3)(-)-N were highest. Mean isotope values in NO(3)(-) ranged from 3.1 to 8.5‰ for δ(15)N and -3.2 to 17.7‰ for δ(18)O. Results suggest that NO(3)(-)-N from the drainage water was derived from organic sources (i.e. manure and soil organic matter) and that loss via denitrification does not impart an identifiable signature upon the NO(3)(-)-N pool. The dual isotope approach examined here provides insight into N source and transformation processes which may be contributing to the NO(3)(-)-N found within the drainage water. PMID:21816538

  19. Evaluating regional trends in ground-water nitrate concentrations of the Columbia Basin ground water management area, Washington

    USGS Publications Warehouse

    Frans, Lonna M.; Helsel, Dennis R.

    2005-01-01

    Trends in nitrate concentrations in water from 474 wells in 17 subregions in the Columbia Basin Ground Water Management Area (GWMA) in three counties in eastern Washington were evaluated using a variety of statistical techniques, including the Friedman test and the Kendall test. The Kendall test was modified from its typical 'seasonal' version into a 'regional' version by using well locations in place of seasons. No statistically significant trends in nitrate concentrations were identified in samples from wells in the GWMA, the three counties, or the 17 subregions from 1998 to 2002 when all data were included in the analysis. For wells in which nitrate concentrations were greater than 10 milligrams per liter (mg/L), however, a significant downward trend of -0.4 mg/L per year was observed between 1998 and 2002 for the GWMA as a whole, as well as for Adams County (-0.35 mg/L per year) and for Franklin County (-0.46 mg/L per year). Trend analysis for a smaller but longer-term 51-well dataset in Franklin County found a statistically significant upward trend in nitrate concentrations of 0.1 mg/L per year between 1986 and 2003. The largest increase of nitrate concentrations occurred between 1986 and 1991. No statistically significant differences were observed in this dataset between 1998 and 2003 indicating that the increase in nitrate concentrations has leveled off.

  20. Watershed Modeling in areas with Intensive Agricultural Irrigation

    NASA Astrophysics Data System (ADS)

    Wyss, J. R.; Watson, B. J.

    2011-12-01

    Irrigation in agricultural intensive watersheds affects soil moisture content, plays a major role in the overall water balance and also influences the hydrologic regime. Historically, irrigation in watershed modeling has been very difficult to simulate and was simulated in one of three general ways. 1) irrigation water was withdrawan from the model and never applied to the land, 2) ignored and assumed insignificant and 3) input as a constant by modifying atmospheric forcing files. For the Loading Simulation Program C++ (LSPC) model developed for the Flint River Watershed in southwest Georgia, we received a summary report of a study conducted to determine irrigation application depth, as well as spatial mapping of irrigated fields in the state of Georgia. The summary report provided minimum, mean, and maximum irrigation depth for both surface water and groundwater sources and the spatial mapping provided over 10,300 irrigated fields located within the boundaries of the Flint River Watershed. With this information we were able to calculate irrigation volume applied to the land by source water type. We discuss how these data were incorporated into the LSPC watershed modeling effort and demonstrate the utility and function of the model for irrigation application. We also investigate impacts to water balance and the hydrologic regime through a series of scenarios in the agriculturally dominated landscape of Ichawaynochaway Creek (HUC 03130009). The scenarios compare and contrast our approach with 1) ignoring irrigation both application and water withdrawal, and 2) only withdrawing the water and not applying it back to the land. We demonstrate the importance of properly simulating irrigation application in heavily influenced areas. The approach we have taken is applicable in other areas in the southeastern United States or any area that is highly influenced by irrigation practices.

  1. Nitrate source indicators in ground water of the Scimitar Subdivision, Peters Creek area, Anchorage, Alaska

    USGS Publications Warehouse

    Wang, Bronwen; Strelakos, Pat M.; Jokela, Brett

    2000-01-01

    A combination of aqueous chemistry, isotopic measurement, and in situ tracers were used to study the possible nitrate sources, the factors contributing to the spatial distribution of nitrate, and possible septic system influence in the ground water in the Scimitar Subdivision, Municipality of Anchorage, Alaska. Two water types were distinguished on the basis of the major ion chemistry: (1) a calcium sodium carbonate water, which was associated with isotopically heavier boron and with chlorofluorocarbons (CFC's) that were in the range expected from equilibration with the atmosphere (group A water) and (2) a calcium magnesium carbonate water, which was associated with elevated nitrate, chloride, and magnesium concentrations, generally isotopically lighter boron, and CFC's concentrations that were generally in excess of that expected from equilibration with the atmosphere (group B water). Water from wells in group B had nitrate concentrations that were greater than 3 milligrams per liter, whereas those in group A had nitrate concentrations of 0.2 milligram per liter or less. Nitrate does not appear to be undergoing extensive transformation in the ground-water system and behaves as a conservative ion. The major ion chemistry trends and the presence of CFC's in excess of an atmospheric source for group B wells are consistent with waste-water influences. The spatial distribution of the nitrate among wells is likely due to the magnitude of this influence on any given well. Using an expanded data set composed of 16 wells sampled only for nitrate concentration, a significant difference in the static water level relative to bedrock was found. Well water samples with less than 1 milligram per liter nitrate had static water levels within the bedrock, whereas those samples with greater than 1 milligram per liter nitrate had static water levels near or above the top of the bedrock. This observation would be consistent with a conceptual model of a low-nitrate fractured bedrock

  2. Estimating the Regional Flux of Nitrate and Agricultural Herbicide Compounds from Groundwater to Headwater Streams of the Northern Atlantic Coastal Plain, USA

    NASA Astrophysics Data System (ADS)

    Ator, S.; Denver, J. M.

    2011-12-01

    Agriculture is common in the Northern Atlantic Coastal Plain (NACP, including New Jersey through North Carolina), and groundwater discharge provides nitrogen (primarily in the form of nitrate) and herbicide compounds from agricultural sources along with the majority of flow to NACP streams. Poor water quality has contributed to ecological degradation of tidal streams and estuaries along much of the adjacent mid-Atlantic coast. Although statistical models have provided estimates of total instream nutrient flux in the Coastal Plain, the regional flux of nitrogen and herbicides during base flow is less well understood. We estimated the regional flux of nitrate and selected commonly used herbicide compounds from groundwater to non-tidal headwater streams of the NACP on the basis of late-winter or spring base-flow samples from 174 such streams. Sampled streams were selected using an unequal-probability random approach, and flux estimates are based on resulting population estimates rather than empirical models, which are commonly used for such estimates. Base-flow flux in the estimated 8,834 NACP non-tidal headwater streams are an estimated 21,200 kilograms per day of nitrate (as N) and 5.83, 0.565, and 20.7 kilograms per day of alachlor, atrazine, and metolachlor (including selected degradates), respectively. Base-flow flux of alachlor and metolachlor is dominated by degradates; flux of parent compounds is less than 3 percent of the total flux of parent plus degradates. Base-flow flux of nitrate and herbicides as a percentage of applications generally varies predictably with regional variations in hydrogeology. Abundant nonpoint (primarily agricultural) sources and hydrogeologic conditions, for example, contribute to particularly large base-flow flux from the Delmarva Peninsula to Chesapeake Bay. In the Delmarva Peninsula part of the Chesapeake Watershed, more than 10 percent of total nonpoint nitrogen applications is transported through groundwater to stream base flow

  3. Agriculture in an area impacted by past uranium mining activities

    SciTech Connect

    Carvalho, F. P.; Oliveira, J. M.; Neves, O.; Vicente, E. M.; Abreu, M. M.

    2007-07-01

    The shallow aquifer near the old Cunha Baixa uranium mine (Viseu, Portugal) was contaminated by acid mine drainage. Concentration of radionuclides in water from irrigation wells and in the topsoil layer of the agriculture fields nearby display enhanced concentrations of uranium, radium and polonium. Two types of agriculture land in this area were selected, one with enhanced and another with low uranium concentrations, for controlled growth of lettuce and potatoes. Plants were grown in replicate portions of land (two plots) in each soil type and were periodically irrigated with water from wells. In each soil, one plot was irrigated with water containing low concentration of dissolved uranium and the other plot with water containing enhanced concentration of dissolved uranium. At the end of the growth season, plants were harvested and analysed, along with soil and irrigation water samples. Results show the accumulation of radionuclides in edible parts of plants, specially in the field plots with higher radionuclide concentrations in soil. Radionuclides in irrigation water contributed less to the radioactivity accumulated in plants than radionuclides from soils. (authors)

  4. Nitrogen Accumulation and Changes in Nitrate Leaching After Four Years of Intensive Forest Culture on Marginal Agricultural Land

    SciTech Connect

    Williams, T.M.; Gresham, C.A.

    2000-02-15

    Loblolly pine and sweetgum were grown with irrigation, continuous fertilizer application and insect pest control on a year old abandoned peanut field. Wells and tension lysimeters were used to measure nitrate-nitrogen in soil moisture and groundwater on three replicate transects for four years. Years 1 and 2, groundwater nitrate-nitrogen concentration exceeded drinking water standards. Years 3 and 4, groundwater nitrate-nitrogen concentration decreased where the greatest reduction occurred in soil moisture at the shallowest depths.

  5. Using generalized additive mixed models to assess spatial, temporal, and hydrologic controls on bacteria and nitrate in a vulnerable agricultural aquifer.

    PubMed

    Mellor, Andrea F P; Cey, Edwin E

    2015-11-01

    The Abbotsford-Sumas aquifer (ASA) has a history of nitrate contamination from agricultural land use and manure application to soils, yet little is known about its microbial groundwater quality. The goal of this study was to investigate the spatiotemporal distribution of pathogen indicators (Escherichia coli [E. coli] and total coliform [TC]) and nitrate in groundwater, and their potential relation to hydrologic drivers. Sampling of 46 wells over an 11-month period confirmed elevated nitrate concentrations, with more than 50% of samples exceeding 10 mg-N/L. E. coli detections in groundwater were infrequent (4 of 385 total samples) and attributed mainly to surface water-groundwater connections along Fishtrap Creek, which tested positive for E. coli in every sampling event. TC was detected frequently in groundwater (70% of samples) across the ASA. Generalized additive mixed models (GAMMs) yielded valuable insights into relationships between TC or nitrate and a range of spatial, temporal, and hydrologic explanatory variables. Increased TC values over the wetter fall and winter period were most strongly related to groundwater temperatures and levels, while precipitation and well location were weaker (but still significant) predictors. In contrast, the moderate temporal variability in nitrate concentrations was not significantly related to hydrologic forcings. TC was relatively widespread across the ASA and spatial patterns could not be attributed solely to surface water connectivity. Varying nitrate concentrations across the ASA were significantly related to both well location and depth, likely due to spatially variable nitrogen loading and localized geochemical attenuation (i.e., denitrification). Vulnerability of the ASA to bacteria was clearly linked to hydrologic conditions, and was distinct from nitrate, such that a groundwater management strategy specifically for bacterial contaminants is warranted. PMID:26348834

  6. Using generalized additive mixed models to assess spatial, temporal, and hydrologic controls on bacteria and nitrate in a vulnerable agricultural aquifer.

    PubMed

    Mellor, Andrea F P; Cey, Edwin E

    2015-11-01

    The Abbotsford-Sumas aquifer (ASA) has a history of nitrate contamination from agricultural land use and manure application to soils, yet little is known about its microbial groundwater quality. The goal of this study was to investigate the spatiotemporal distribution of pathogen indicators (Escherichia coli [E. coli] and total coliform [TC]) and nitrate in groundwater, and their potential relation to hydrologic drivers. Sampling of 46 wells over an 11-month period confirmed elevated nitrate concentrations, with more than 50% of samples exceeding 10 mg-N/L. E. coli detections in groundwater were infrequent (4 of 385 total samples) and attributed mainly to surface water-groundwater connections along Fishtrap Creek, which tested positive for E. coli in every sampling event. TC was detected frequently in groundwater (70% of samples) across the ASA. Generalized additive mixed models (GAMMs) yielded valuable insights into relationships between TC or nitrate and a range of spatial, temporal, and hydrologic explanatory variables. Increased TC values over the wetter fall and winter period were most strongly related to groundwater temperatures and levels, while precipitation and well location were weaker (but still significant) predictors. In contrast, the moderate temporal variability in nitrate concentrations was not significantly related to hydrologic forcings. TC was relatively widespread across the ASA and spatial patterns could not be attributed solely to surface water connectivity. Varying nitrate concentrations across the ASA were significantly related to both well location and depth, likely due to spatially variable nitrogen loading and localized geochemical attenuation (i.e., denitrification). Vulnerability of the ASA to bacteria was clearly linked to hydrologic conditions, and was distinct from nitrate, such that a groundwater management strategy specifically for bacterial contaminants is warranted.

  7. Using generalized additive mixed models to assess spatial, temporal, and hydrologic controls on bacteria and nitrate in a vulnerable agricultural aquifer

    NASA Astrophysics Data System (ADS)

    Mellor, Andrea F. P.; Cey, Edwin E.

    2015-11-01

    The Abbotsford-Sumas aquifer (ASA) has a history of nitrate contamination from agricultural land use and manure application to soils, yet little is known about its microbial groundwater quality. The goal of this study was to investigate the spatiotemporal distribution of pathogen indicators (Escherichia coli [E. coli] and total coliform [TC]) and nitrate in groundwater, and their potential relation to hydrologic drivers. Sampling of 46 wells over an 11-month period confirmed elevated nitrate concentrations, with more than 50% of samples exceeding 10 mg-N/L. E. coli detections in groundwater were infrequent (4 of 385 total samples) and attributed mainly to surface water-groundwater connections along Fishtrap Creek, which tested positive for E. coli in every sampling event. TC was detected frequently in groundwater (70% of samples) across the ASA. Generalized additive mixed models (GAMMs) yielded valuable insights into relationships between TC or nitrate and a range of spatial, temporal, and hydrologic explanatory variables. Increased TC values over the wetter fall and winter period were most strongly related to groundwater temperatures and levels, while precipitation and well location were weaker (but still significant) predictors. In contrast, the moderate temporal variability in nitrate concentrations was not significantly related to hydrologic forcings. TC was relatively widespread across the ASA and spatial patterns could not be attributed solely to surface water connectivity. Varying nitrate concentrations across the ASA were significantly related to both well location and depth, likely due to spatially variable nitrogen loading and localized geochemical attenuation (i.e., denitrification). Vulnerability of the ASA to bacteria was clearly linked to hydrologic conditions, and was distinct from nitrate, such that a groundwater management strategy specifically for bacterial contaminants is warranted.

  8. Productivity of Premodern Agriculture in the Cucuteni-Trypillia Area.

    PubMed

    Shukurov, Anvar; Sarson, Graeme; Videiko, Mykhailo; Henderson, Kate; Shiel, Robert; Dolukhanov, Pavel; Pashkevich, Galina

    2015-07-01

    We present paleoeconomy reconstructions for premodern agriculture, selecting, wherever required, features and parameter values specific for the Cucuteni-Trypillia cultural unity (CTU; 5,400-2,700 BC, mostly the territory of modern Ukraine, Moldova, and Romania). We verify the self-consistency and viability of the archaeological evidence related to all major elements of the agricultural production cycle within the constraints provided by environmental and technological considerations. The starting point of our analysis is the paleodiet structure suggested by archaeological data, stable isotope analyses of human remains, and palynology studies in the CTU area. We allow for the archeologically attested contributions of domesticated and wild animal products to the diet, develop plausible estimates of the yield of ancient cereal varieties cultivated with ancient techniques, and quantify the yield dependence on the time after initial planting and on rainfall (as a climate proxy). Our conclusions involve analysis of the labor costs of various seasonal parts of the agricultural cycle of both an individual and a family with a majority of members that do not engage in productive activities that require physical fitness, such as tillage. Finally, we put our results into the context of the exploitation territory and catchment analysis, to project various subsistence strategies into the exploitation territory of a farming settlement. The simplest economic complex based on cereals and domestic and wild animal products, with fallow cropping, appears to be capable of supporting an isolated, relatively small farming settlement of 50-300 people (2-10 ha in area) even without recourse to technological improvements such as the use of manure fertilizer. Our results strongly suggest that dairy products played a significant role in the dietary and labor balance. The smaller settlements are typical of the earliest Trypillia A stage but remain predominant at the later stages. A larger

  9. Productivity of Premodern Agriculture in the Cucuteni-Trypillia Area.

    PubMed

    Shukurov, Anvar; Sarson, Graeme; Videiko, Mykhailo; Henderson, Kate; Shiel, Robert; Dolukhanov, Pavel; Pashkevich, Galina

    2015-07-01

    We present paleoeconomy reconstructions for premodern agriculture, selecting, wherever required, features and parameter values specific for the Cucuteni-Trypillia cultural unity (CTU; 5,400-2,700 BC, mostly the territory of modern Ukraine, Moldova, and Romania). We verify the self-consistency and viability of the archaeological evidence related to all major elements of the agricultural production cycle within the constraints provided by environmental and technological considerations. The starting point of our analysis is the paleodiet structure suggested by archaeological data, stable isotope analyses of human remains, and palynology studies in the CTU area. We allow for the archeologically attested contributions of domesticated and wild animal products to the diet, develop plausible estimates of the yield of ancient cereal varieties cultivated with ancient techniques, and quantify the yield dependence on the time after initial planting and on rainfall (as a climate proxy). Our conclusions involve analysis of the labor costs of various seasonal parts of the agricultural cycle of both an individual and a family with a majority of members that do not engage in productive activities that require physical fitness, such as tillage. Finally, we put our results into the context of the exploitation territory and catchment analysis, to project various subsistence strategies into the exploitation territory of a farming settlement. The simplest economic complex based on cereals and domestic and wild animal products, with fallow cropping, appears to be capable of supporting an isolated, relatively small farming settlement of 50-300 people (2-10 ha in area) even without recourse to technological improvements such as the use of manure fertilizer. Our results strongly suggest that dairy products played a significant role in the dietary and labor balance. The smaller settlements are typical of the earliest Trypillia A stage but remain predominant at the later stages. A larger

  10. 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...

  11. Dynamics of nitrate and chloride during storm events in agricultural catchments with different subsurface drainage intensity (Indiana, USA)

    NASA Astrophysics Data System (ADS)

    Kennedy, Casey D.; Bataille, Clement; Liu, Zhongfang; Ale, Srinivasulu; VanDeVelde, Justin; Roswell, Charles R.; Bowling, Laura C.; Bowen, Gabriel J.

    2012-10-01

    SummaryDrainage tiles buried beneath many naturally poorly drained agricultural fields in the Midwestern U.S. are believed to "short circuit" pools of NO3--laden soil water and shallow groundwater directly into streams that eventually discharge to the Mississippi River. Although much is known about the mechanisms controlling this regionally pervasive practice of artificial drainage at the field-plot scale, an integrative assessment of the effect of drainage density (i.e., the number of tile drains per unit area) on the transport of nutrients and solutes in streams at the catchment scale is lacking. In this study, we quantified the flux and hydrological pathways of agricultural NO3- and road-salt Cl- from catchments lying within the Wabash River Basin, a major source of NO3- to the Mississippi River. The paired catchments differ primarily in drainage density (70% vs. 31%, by catchment area), with essentially all other agricultural management, land use, and soil drainage characteristics remaining equal. Our study revealed two significant hydrological responses to increased drainage density: (1) more near-surface storm event water (dilute in both NO3- and Cl) was transported early in the storm and (2) higher transport of Cl--laden pre-event soil water relative to shallow groundwater elevated in NO3- occurred later in the storm. These patterns are consistent with a proposed conceptual model in which increased drainage density results in (1) greater transport of soil water to streams and (2) a delayed rise in the water table. With respect to nutrient management implications, these results indicate that increased drainage density impacts subsurface pools of Cl- and NO3- differently, a finding that we propose is linked to soil/ground water dynamics in artificially drained agricultural catchments.

  12. The nitrate time bomb: a numerical way to investigate nitrate storage and lag time in the unsaturated zone.

    PubMed

    Wang, L; Butcher, A S; Stuart, M E; Gooddy, D C; Bloomfield, J P

    2013-10-01

    Nitrate pollution in groundwater, which is mainly from agricultural activities, remains an international problem. It threatens the environment, economics and human health. There is a rising trend in nitrate concentrations in many UK groundwater bodies. Research has shown it can take decades for leached nitrate from the soil to discharge into groundwater and surface water due to the 'store' of nitrate and its potentially long travel time in the unsaturated and saturated zones. However, this time lag is rarely considered in current water nitrate management and policy development. The aim of this study was to develop a catchment-scale integrated numerical method to investigate the nitrate lag time in the groundwater system, and the Eden Valley, UK, was selected as a case study area. The method involves three models, namely the nitrate time bomb-a process-based model to simulate the nitrate transport in the unsaturated zone (USZ), GISGroundwater--a GISGroundwater flow model, and N-FM--a model to simulate the nitrate transport in the saturated zone. This study answers the scientific questions of when the nitrate currently in the groundwater was loaded into the unsaturated zones and eventually reached the water table; is the rising groundwater nitrate concentration in the study area caused by historic nitrate load; what caused the uneven distribution of groundwater nitrate concentration in the study area; and whether the historic peak nitrate loading has reached the water table in the area. The groundwater nitrate in the area was mainly from the 1980s to 2000s, whilst the groundwater nitrate in most of the source protection zones leached into the system during 1940s-1970s; the large and spatially variable thickness of the USZ is one of the major reasons for unevenly distributed groundwater nitrate concentrations in the study area; the peak nitrate loading around 1983 has affected most of the study area. For areas around the Bowscar, Beacon Edge, Low Plains, Nord Vue

  13. The nitrate time bomb: a numerical way to investigate nitrate storage and lag time in the unsaturated zone.

    PubMed

    Wang, L; Butcher, A S; Stuart, M E; Gooddy, D C; Bloomfield, J P

    2013-10-01

    Nitrate pollution in groundwater, which is mainly from agricultural activities, remains an international problem. It threatens the environment, economics and human health. There is a rising trend in nitrate concentrations in many UK groundwater bodies. Research has shown it can take decades for leached nitrate from the soil to discharge into groundwater and surface water due to the 'store' of nitrate and its potentially long travel time in the unsaturated and saturated zones. However, this time lag is rarely considered in current water nitrate management and policy development. The aim of this study was to develop a catchment-scale integrated numerical method to investigate the nitrate lag time in the groundwater system, and the Eden Valley, UK, was selected as a case study area. The method involves three models, namely the nitrate time bomb-a process-based model to simulate the nitrate transport in the unsaturated zone (USZ), GISGroundwater--a GISGroundwater flow model, and N-FM--a model to simulate the nitrate transport in the saturated zone. This study answers the scientific questions of when the nitrate currently in the groundwater was loaded into the unsaturated zones and eventually reached the water table; is the rising groundwater nitrate concentration in the study area caused by historic nitrate load; what caused the uneven distribution of groundwater nitrate concentration in the study area; and whether the historic peak nitrate loading has reached the water table in the area. The groundwater nitrate in the area was mainly from the 1980s to 2000s, whilst the groundwater nitrate in most of the source protection zones leached into the system during 1940s-1970s; the large and spatially variable thickness of the USZ is one of the major reasons for unevenly distributed groundwater nitrate concentrations in the study area; the peak nitrate loading around 1983 has affected most of the study area. For areas around the Bowscar, Beacon Edge, Low Plains, Nord Vue

  14. Impacts of management and climate change on nitrate leaching in a forested karst area.

    PubMed

    Thomas, Dirnböck; Johannes, Kobler; David, Kraus; Rüdiger, Grote; Ralf, Kiese

    2016-01-01

    Forest management and climate change, directly or indirectly, affect drinking water resources, both in terms of quality and quantity. In this study in the Northern Limestone Alps in Austria we have chosen model calculations (LandscapeDNDC) in order to resolve the complex long-term interactions of management and climate change and their effect on nitrogen dynamics, and the consequences for nitrate leaching from forest soils into the karst groundwater. Our study highlights the dominant role of forest management in controlling nitrate leaching. Both clear-cut and shelterwood-cut disrupt the nitrogen cycle to an extent that causes peak concentrations and high fluxes into the seepage water. While this effect is well known, our modelling approach has revealed additional positive as well as negative impacts of the expected climatic changes on nitrate leaching. First, we show that peak nitrate concentrations during post-cutting periods were elevated under all climate scenarios. The maximal effects of climatic changes on nitrate concentration peaks were 20-24 mg L(-1) in 2090 with shelterwood or clear-cut management. Second, climate change significantly decreased the cumulative nitrate losses over full forest rotation periods (by 10-20%). The stronger the expected temperature increase and precipitation decrease (in summer), the lesser were the observed nitrate losses. However, mean annual seepage water nitrate concentrations and cumulative nitrate leaching were higher under continuous forest cover management than with shelterwood-cut and clear-cut systems. Watershed management can thus be adapted to climate change by either reducing peak concentrations or long-term loads of nitrate in the karst groundwater.

  15. Impacts of management and climate change on nitrate leaching in a forested karst area.

    PubMed

    Thomas, Dirnböck; Johannes, Kobler; David, Kraus; Rüdiger, Grote; Ralf, Kiese

    2016-01-01

    Forest management and climate change, directly or indirectly, affect drinking water resources, both in terms of quality and quantity. In this study in the Northern Limestone Alps in Austria we have chosen model calculations (LandscapeDNDC) in order to resolve the complex long-term interactions of management and climate change and their effect on nitrogen dynamics, and the consequences for nitrate leaching from forest soils into the karst groundwater. Our study highlights the dominant role of forest management in controlling nitrate leaching. Both clear-cut and shelterwood-cut disrupt the nitrogen cycle to an extent that causes peak concentrations and high fluxes into the seepage water. While this effect is well known, our modelling approach has revealed additional positive as well as negative impacts of the expected climatic changes on nitrate leaching. First, we show that peak nitrate concentrations during post-cutting periods were elevated under all climate scenarios. The maximal effects of climatic changes on nitrate concentration peaks were 20-24 mg L(-1) in 2090 with shelterwood or clear-cut management. Second, climate change significantly decreased the cumulative nitrate losses over full forest rotation periods (by 10-20%). The stronger the expected temperature increase and precipitation decrease (in summer), the lesser were the observed nitrate losses. However, mean annual seepage water nitrate concentrations and cumulative nitrate leaching were higher under continuous forest cover management than with shelterwood-cut and clear-cut systems. Watershed management can thus be adapted to climate change by either reducing peak concentrations or long-term loads of nitrate in the karst groundwater. PMID:26439862

  16. Three Dimensional Modeling of Agricultural Contamination of Groundwater: a Case Study in the Nebraska Management Systems Evaluation Area (MSEA) Site

    NASA Astrophysics Data System (ADS)

    Akbariyeh, S.; Snow, D. D.; Bartelt-Hunt, S.; Li, X.; Li, Y.

    2015-12-01

    Contamination of groundwater from nitrogen fertilizers and pesticides in agricultural lands is an important environmental and water quality management issue. It is well recognized that in agriculturally intensive areas, fertilizers and pesticides may leach through the vadose zone and eventually reach groundwater, impacting future uses of this limited resource. While numerical models are commonly used to simulate fate and transport of agricultural contaminants, few models have been validated based on realistic three dimensional soil lithology, hydrological conditions, and historical changes in groundwater quality. In this work, contamination of groundwater in the Nebraska Management Systems Evaluation Area (MSEA) site was simulated based on extensive field data including (1) lithology from 69 wells and 11 test holes; (2) surface soil type, land use, and surface elevations; (3) 5-year groundwater level and flow velocity; (4) daily meteorological monitoring; (5) 5-year seasonal irrigation records; (6) 5-years of spatially intensive contaminant concentration in 40 multilevel monitoring wells; and (7) detailed cultivation records. Using this data, a three-dimensional vadose zone lithological framework was developed using a commercial software tool (RockworksTM). Based on the interpolated lithology, a hydrological model was developed using HYDRUS-3D to simulate water flow and contaminant transport. The model was validated through comparison of simulated atrazine and nitrate concentration with historical data from 40 wells and multilevel samplers. The validated model will be used to predict potential changes in ground water quality due to agricultural contamination under future climate scenarios in the High Plain Aquifer system.

  17. Water quality of the Apalachicola-Chattahoochee-Flint and Ocmulgee river basins related to flooding from Tropical Storm Alberto; pesticides in urban and agricultural watersheds, and nitrate and pesticides in ground water, Georgia, Alabama, and Florida

    USGS Publications Warehouse

    Hippe, D.J.; Wangsness, D.J.; Frick, E.A.; Garrett, J.W.

    1994-01-01

    This report presents preliminary water-quality information from three studies that are part of the National Water-Quality Assessment (NAWQA) Program in the Apalachicola-Chattahoochee-Flint (ACF) River basin and the adjacent Ocmulgee River basin. During the period July 3-7, 1994, heavy rainfall from tropical storm Alberto caused record flooding on the Ocmulgee and Flint Rivers and several of their tributaries. Much of the nitrogen load transported during the flooding was as organic nitrogen generally derived from organic detritus, rather than nitrate derived from other sources, such as fertilizer. More than half the mean annual loads of total phosphorus and organic nitrogen were trans- ported in the Flint and Ocmulgee Rivers during the flood. Fourteen herbicides, five insecticides, and one fungicide were detected in floodwaters of the Ocmulgee, Flint, and Apalachicola Rivers. In a second study, water samples were collected at nearly weekly intervals from March 1993 through April 1994 from one urban and two agricultural watersheds in the ACF River basin, and analyzed for 84 commonly used pesticides. More pesticides were detected and at generally higher concentrations in water from the urban watershed than the agricultural water- sheds, and a greater number of pesticides were persistent throughout much of the year in the urban watershed. Simazine exceeded U.S. Environmental Protection Agency (EPA) drinking-water standards in one of 57 samples from the urban watershed. In a third study, 38 wells were installed in surficial aquifers adjacent to and downgradient of farm fields within agricultural areas in the southern ACF River basin. Even though regional aquifers are generally used for irrigation and domestic- and public-water supplies, degradation of water quality in the surficial aquifers serves as an early warning of potential contamination of regional aquifers. Nitrate concentrations were less than 3 mg/L as N (indicating minimal effect of human activities) in water

  18. Assessment of nitrate leakage and N2O emission from five environmental-friendly agricultural practices using fuzzy logic method and empirical formula.

    PubMed

    Qin, Lihuan; Wang, Yan; Wu, Yongfeng; Wang, Qian; Luo, Liangguo

    2015-06-01

    Agricultural nonpoint source pollution in China has been the major environmental problem, so environmental-friendly agricultural practices (EAPs) must be promoted to improve environmental quality. However, the most suitable practices for each agricultural region must first be identified. Thus, in the presented study a fuzzy-logic method and a revised empirical formula were used to assess nitrate leakage and N2O emissions, respectively, and to compare five EAPs in Xinxiang, a major grain-producing county in Henan Province, China. The required information was collected in face-to-face interviews with 10 extension service experts from the county, using a questionnaire to explore their opinions of the EAPs currently adopted by smallholder farmers, as well as the amounts, frequencies, varieties and proportions of nitrogen fertilizers applied annually. The results indicate that reduced tillage, soil testing and fertilizer recommendations would be the most appropriate practices to initially promote on a large scale in Xinxiang.

  19. Nitrate enrichment in groundwater from long-term intensive agriculture: its mechanistic pathways and prediction through modeling.

    PubMed

    Kundu, Manik Chandra; Mandal, Biswapati

    2009-08-01

    Nitrate (NO(3-)N) contamination of drinking groundwater is a serious worldwide problem. We studied the mechanistic pathways of the nitrate enrichment in a drinking groundwater system of an intensively cultivated district in India and predicted the enrichment through modeling. Analysis of groundwater samples (3472) showed that the nitrate content during the postmonsoon season (0.87 mg L(-1)) was higher than the nitrate content during the premonsoon season (0.58 mg L(-1)). It decreased with increasing depth of the aquifers sampled (r = -0.38), decreasing N-fertilizer application rate (r = 0.74), increasing average root length of the cropping systems followed (r = -0.54), and their efficacy for N-utilization (r = -0.61). Soil properties (136 representative samples) like bulk density (r = -0.72), hydraulic conductivity (r = 0.56), clay (r = -0.29), organic carbon (r = 0.72), NO(3-)N (r = 0.82), and potentially plantavailable soil N (pAvN) (r = 0.82) added to the variability of its enrichment. Prediction of nitrate enrichment by multiple regression equations with selected mastervariables explained 83.6-85.8% of the variability. Results indicate that potentially plant available soil nitrogen, commonly measured for fertilizer recommendation, may help in predicting nitrate enrichment under long-term intensively cultivated alluvial agroecosystems.

  20. Managing the drinking water catchment areas: the French agricultural cooperatives feed back.

    PubMed

    Charrière, Séverine; Aumond, Claire

    2016-06-01

    The quality of raw water is problematic in France, largely polluted by nitrates and pesticides (Mueller and Helsel, Nutrients in the nation's waters-too much of a good thing? Geological Survey (U.S.), 1996; European Environment Agency, European waters-assessment of status and pressures, 2012).This type of pollution, even though not always due to agriculture (example of the catchment of Ambleville, county 95, France where the nitrate pollution is mainly due to sewers (2012)), has been largely related to the agricultural practices (Sci Total Environ 407:6034-6043, 2009).Taking note of this observation, and instead of letting it paralyze their actions, the agricultural cooperatives decided with Agrosolutions to act directly on the field with their subscribers to change the agricultural practices impacting the water and the environment.This article shows how the French agricultural cooperatives transformed the awareness of the raw water quality problem into an opportunity for the development and implementation of more precise and responsible practices, to protect their environment. They measure in order to pilot, co-construct and build the best action plans possible according to the three pillars of environment, economy and agronomy.

  1. Managing the drinking water catchment areas: the French agricultural cooperatives feed back.

    PubMed

    Charrière, Séverine; Aumond, Claire

    2016-06-01

    The quality of raw water is problematic in France, largely polluted by nitrates and pesticides (Mueller and Helsel, Nutrients in the nation's waters-too much of a good thing? Geological Survey (U.S.), 1996; European Environment Agency, European waters-assessment of status and pressures, 2012).This type of pollution, even though not always due to agriculture (example of the catchment of Ambleville, county 95, France where the nitrate pollution is mainly due to sewers (2012)), has been largely related to the agricultural practices (Sci Total Environ 407:6034-6043, 2009).Taking note of this observation, and instead of letting it paralyze their actions, the agricultural cooperatives decided with Agrosolutions to act directly on the field with their subscribers to change the agricultural practices impacting the water and the environment.This article shows how the French agricultural cooperatives transformed the awareness of the raw water quality problem into an opportunity for the development and implementation of more precise and responsible practices, to protect their environment. They measure in order to pilot, co-construct and build the best action plans possible according to the three pillars of environment, economy and agronomy. PMID:27074925

  2. Monitoring and Modelling of the Long-term Effect of Changing Agriculture on Nitrate Concentrations in Groundwater and Streams in Small Experimental subsurface dominant watersheds

    NASA Astrophysics Data System (ADS)

    Fovet, Ophelie; Hrachowitz, Markus; Ruiz, Laurent; Faucheux, Mikael; Aquilina, Luc; Molenat, Jerome; Durand, Patrick; Gascuel-Odoux, Chantal

    2013-04-01

    Management and prediction of water quality in watersheds is critical especially in agricultural regions. Water quality in watersheds varies in a very broad range of temporal scales, from storm events or diurnal cycles, seasonal cycles, to pluriannual trends. It varies also spatially, with contrasted dynamics of solutes in the soil, the recharge, the groundwater and the streams. This is challenging both in term of monitoring and of modelling. Agricultural watershed are interesting to discriminate short term from long term mechanisms, as most of them experienced drastic changes in agricultural inputs in the past 50 years. Recently, the analysis of long-term stream water quality data sets has allowed improving significantly our understanding of solute residence time in watersheds [1]. However, as historical agricultural practices are usually poorly documented, large assumptions are needed to achieve such exercises. Despite the large amount of research in the past 30 years dedicated to understand and model the dynamics of agricultural-borne diffuse pollution at the watershed level, there is no accepted perceptual model explaining the observed dynamics of water quality simultaneously at all the relevant spatial and temporal scales and a very little number of sites sufficiently documented to test it. We present results from a long-term comprehensive monitoring of agricultural inputs and chemistry of surface water (20 years) and groundwater (10 years) in small experimental watersheds (ORE AgrHys, http://www.inra.fr/ore_agrhys/). Results showed (i) a strong stability in the stream chemistry whereas agricultural inputs in these small watersheds were highly variable from year to year, (ii) a high spatial heterogeneity of the groundwater chemistry, both laterally along the hillslope and vertically and (iii) contrasted behavior of long-term trends in agricultural inputs and nitrate concentration in groundwater. A simple model was developed, based on linear reservoirs, and run

  3. Estimation of the seasonal variation of particulate nitrate and sensitivity to the emission changes in the greater Seoul area

    NASA Astrophysics Data System (ADS)

    Lee, Sihye; Ghim, Young Sung; Kim, Yong Pyo; Kim, Jin Young

    Seasonal variation of fine particulate nitrate and sensitivity of fine particle mass concentration to the emission changes of VOCs and NO x were estimated in the greater Seoul area. SBOX, a photochemical box model was used to obtain the total nitric acid (HNO 3T) concentration, and SCAPE2, a gas/particle equilibrium model was used to determine the partitioning of nitric acid/nitrate and particulate water content. Most HNO 3T existed as nitrate except in summer (˜60%) since there was enough ammonia to form particulate ammonium nitrate. In summer, high temperature was favorable to gaseous nitric acid. Also, because of average relative humidity (RH) higher than the deliquescence points of most salts, water content in summer was higher than those in other seasons by a factor of two. For all seasons, fine particle mass concentration (the sum of ion concentrations and water content) increased until considerable amount of NO x emissions was reduced. This phenomenon is a typical example of the so-called 'NO x disbenefits' that has been discussed in relation to the abatement of ozone pollution.

  4. Genotoxicity of agricultural soils in the vicinity of industrial area.

    PubMed

    Ansari, Mohd Ikram; Malik, Abdul

    2009-03-17

    Soil samples from agricultural fields (cultivated) in the vicinity of industrial area of Ghaziabad City (India) were collected. In this city, wastewater coming from both industrial and domestic sources and without any treatment is used to irrigate the food crops. This practice has been polluting the soil and pollutants might reach the food chain. Gas chromatographic analysis show the presence of certain organochlorine (DDE, DDT, dieldrin, aldrin and endosulfan) and organophosphorus (dimethoate, malathion, methylparathion and chlorpyrifos) pesticides in soil samples. Samples were extracted using different solvents, i.e. methanol, chloroform, acetonitrile, hexane and acetone (all were HPLC-grade, SRL, India), and the extracts were assayed for genotoxic potential using Ames Salmonella/microsome test, DNA repair defective mutants and bacteriophage lambda systems. TA98 and TA100 were found to be the most sensitive strains to all the soil extracts tested. Methanol extracts exhibited a maximum mutagenicity with TA98 strain {540 (-S9) and 638 (+S9) revertants/g of soil} and 938 (-S9) and 1008 (+S9) revertants/g of soil with TA100 strain. The damage in the DNA repair defective mutants was found maximum with methanolic extract followed by acetonitrile, chloroform, hexane and acetone at the dose level of 40 microl/ml culture after 6h of treatment. The survival was 25, 30, 32, 33 and 35% in polA strain after 6h of treatment when tested with wastewater irrigated soil extracts of methanol, acetonitrile, chloroform, hexane and acetone, respectively. A significant decrease in the plaque forming units of bacteriophage lambda was also observed when treated with 40 microl of test samples. Present results showed that methanolic extracts of soil were more toxic than other soil extracts. The soil is accumulating a large number of pollutants due to wastewater irrigation and this practice of accumulation has an impact on soil health.

  5. OCCUPATIONAL OPPORTUNITIES AND TRAINING NEEDS FOR NONFARM AGRICULTURAL JOBS IN THE METROPOLITAN AREAS OF LOUISIANA.

    ERIC Educational Resources Information Center

    CURTIS, C.M.; MONDART, C.L.

    A SURVEY OF 1,067 BUSINESSES OR AGENCIES HANDLING FARM PRODUCTS OR PROVIDING AGRICULTURAL SERVICE IN SEVEN METROPOLITAN AREAS IDENTIFIED PRESENT AND EMERGING AGRICULTURAL OCCUPATIONS OTHER THAN FARMING AND RANCHING FOR WHICH INSTRUCTION IN VOCATIONAL AGRICULTURE SHOULD BE MADE AVAILABLE. DATA PROVIDED EMPLOYEE INFORMATION FOR SELECTED OCCUPATIONAL…

  6. Agricultural area impacts within a natural area: Cades cove, a case history

    NASA Astrophysics Data System (ADS)

    Bratton, Susan Power; Mathews, Raymond C.; White, Peter S.

    1980-09-01

    Agricultural management in Cades Cove, an historic district in Great Smoky Mountains National Park, has affected natural resources both within the district and in the adjoining natural areas. Aquatic impacts of haying and cattle grazing included increases in water temperatures, turbidity, nutrient loading, and bacterial counts and decreases in benthic macroinvertebrate density and fish biomass. Wildlife populations, including groundhogs, wild turkeys, and white-tailed deer, have increased in the open fields and around the periphery of the historic district. Intensive deer foraging has removed deciduous seedlings and saplings from woodlots, lowering species diversity and favoring coniferous reproduction. Cades Cove has limestone habitats unique in the park, and both deer browse and cattle grazing may have disturbed populations of rare plant species. Effects on water quality are detectable at a campground 15 stream km from the agricultural area, and the effects of deer foraging extend about 1 km beyond the open fields. Since “historic landscape” preservation is presently a goal of the park, managing for open vistas in Cades Cove will require some sort of continuing disturbance. Conversion of cattle pastures to hayfields would reduce aquatic impacts but the deer herd might increase as a result of reduced competition for forage. Retarding old field succession would increase populations of native plant species dependent on sunlight, but would require government-funded mowing. Other options are discussed. Completely eliminating the effects of the historic district on adjoining areas may be impossible, at least under present economic constraints.

  7. 7 CFR 3402.4 - Food and agricultural sciences areas targeted for National Needs Graduate and Postdoctoral...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Food and agricultural sciences areas targeted for... Agriculture Regulations of the Department of Agriculture (Continued) COOPERATIVE STATE RESEARCH, EDUCATION, AND EXTENSION SERVICE, DEPARTMENT OF AGRICULTURE FOOD AND AGRICULTURAL SCIENCES NATIONAL...

  8. Continuing importance of nitrate contamination of groundwater and wells in rural areas.

    PubMed

    Johnson, C J; Kross, B C

    1990-01-01

    The contamination of groundwater and rural drinking water supplies by nitrates from livestock and human excrement, other organic waste, or chemical fertilizers is a potential hazard throughout the world. Infant illness and death from nitrate-induced methemoglobinemia is probably often misdiagnosed, perhaps as sudden infant death syndrome, and certainly contributes to the national infant death rate statistics. A 1950 report listed 144 cases of infant methemoglobinemia with 14 deaths in one 30-month period in Minnesota. Infant deaths resulting from misdiagnosis of this preventable, treatable intoxication were still occurring as recently as 1986 in South Dakota. In this state, about 39% of dug or bored wells were unsafe due to high nitrate content, compared with 22% of drilled wells and 16% of driven wells. Properly constructed wells more than 30 m deep are more likely to be safe. Groundwater concentrations of nitrate may be unsafe for consumption, and standards are needed to regulate such contamination. Such standards could serve as guidelines and could be enforceable in the case of water systems dependent on wells.

  9. Sustainability Assessment for Agriculture Scenarios in Europe's Mountain Areas: Lessons from Six Study Areas

    NASA Astrophysics Data System (ADS)

    Partidário, Maria Rosário; Sheate, William R.; Bina, Olivia; Byron, Helen; Augusto, Bernardo

    2009-01-01

    Sustainability assessment (SA) is a holistic and long-range strategic instrument capable of assisting policy-making in electing, and deciding upon, future development priorities. The outcomes of an SA process become more relevant and strengthened when conducted with multi-stakeholder engagement, which provides for multiple dialogues and perspectives. This was the object of research of the SA team in the context of BioScene ( Scenarios for Reconciling Biodiversity Conservation with Declining Agriculture Use in Mountain Areas in Europe), a three-year project (2002-2005) funded by the European Union 5th Framework Program, which aimed to investigate the implications of agricultural restructuring and decline for biodiversity conservation in the mountain areas of Europe, using three distinct methodological streams: the ecological, the socio-economic, and the SA approaches. The SA approach drew on the previous two to assess the importance for biodiversity management of different scenarios of agri-environmental change and rural policy in six countries (France, Greece, Norway, Slovakia, Switzerland, and the United Kingdom), develop causal chains, include stakeholder views, and identify potential contributions for, or conflicts with, sustainability. This article tells how SA was used, what sustainability meant in each study area through different objectives of sustainability considered, discusses the methods used in SA, and the benefits arising. The SA was conducted by a team independent of any study area, who developed and oversaw the application of the SA methodology, assisting national teams, and developing a cross-country understanding of the sustainability of proposed scenarios in the different geographical and social contexts, and their implications for policy-making. Finally, it reflects on the persistent challenges of interdisciplinary research, compounded by multi-cultural teams, and concludes on the BioScene’s lessons for the further development and application

  10. Alternatives for reducing nitrate in municipal water supplies

    SciTech Connect

    Guter, G.A.; Kartinen, E.O. )

    1989-01-01

    A project to reduce nitrate levels in drinking water supplied to the community of McFarland, California is described. Intense irrigation of the surrounding area subjects the community to ground water pollution from agricultural chemicals and by products. Nitrates ranged from 40 to 100mg/L (as NO3) in water supplied from wells. Costs and operational data of a 1 mgd ion exchange plant are presented. Costs and data for a recently constructed 1 mgd plant are also reviewed. Data from other nitrate plants now under construction are presented. Future research involving the use of nitrate selective resins and waste brine recovery and recycling is reviewed.

  11. GAMM's as a New Tool for Evaluating Spatiotemporal Distributions of Nitrate and Bacteria in an Agricultural Watershed

    NASA Astrophysics Data System (ADS)

    Cey, E. E.; Mellor, A. F.

    2015-12-01

    Generalized additive mixed models (GAMM's) are flexible regression models that are increasingly used in ecological and environmental studies to assess spatial and temporal trends in complex monitoring data. GAMM's hold promise for analysis of spatially and temporally correlated hydrogeologic data, but have been used only sparingly. Here we employed GAMM's to investigate the spatiotemporal distribution of pathogen indicators (E. coli and total coliform [TC]) and nitrate in the vulnerable Abbotsford-Sumas aquifer (ASA), and to explore potential relationships with hydrologic and climatic drivers, such as precipitation, streamflow, and groundwater level and temperature. A total of 46 wells sampled over a one year period showed more than 50% of samples exceeded 10 mg-N/L for nitrate. E. coli detections in groundwater were infrequent (4 of 385 total samples) and attributed mainly to surface water-groundwater connections. TC was detected frequently in groundwater (70% of samples) and the widespread TC distribution across the ASA could not be attributed solely to surface water connectivity. GAMM's showed that increased TC values in the wet season were most strongly related to groundwater temperatures and levels, while precipitation and well location were weaker (but still significant) predictors. In contrast, seasonal trends in nitrate were not significantly related to hydrologic forcings. Instead, nitrate concentrations across the aquifer were controlled by well location and depth, likely due to spatially variable nitrogen loading and localized geochemical attenuation. Major differences in nitrate and bacterial loading to the ASA were apparent in this study, and management strategies specific to each nonpoint source contaminant are recommended for improved source water protection.

  12. A Review of Effectiveness of Riparian Buffers in Agricultural Areas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There has been growing recognition of the importance of riparian buffers between agricultural fields and waterbodies in recent years. Riparian buffers play an important role in mitigating the impacts of land use activities on water quality and aquatic ecosystems. Riparian buffer systems have been st...

  13. A decision support system for rainfed agricultural areas of Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rural inhabitants of arid lands lack sufficient water to fulfill their agricultural and household needs. They do not have readily available technical information to support decisions regarding the course of action they should follow to handle the agro-climatic risk. In this paper, a computer model (...

  14. [Characteristics of soil nematode community of different agricultural areas in Jiangsu Province, China].

    PubMed

    Jiao, Jia-guo; Liu, Bei-bei; Mao, Miao; Ye, Cheng-long; Yu, Li; Hu, Feng

    2015-11-01

    This paper investigated the genus diversity of soil nematodes of different agricultural areas in Jiangsu Province, analyzed the relationship between soil nematodes and soil environmental factors, and discussed the roles of soil nematodes as biological indicators of soil health. The results showed that, a total of 41 nematode genera were found in all six agricultural areas, belonging to 19 families, 7 orders, 2 classes. The numbers and community compositions of nematodes were obviously influenced by soil texture, fertilization and tillage practices. In all six agricultural areas, the numbers of nematodes in coastal agricultural area (400 individuals per 100 g dry soil) were significantly larger than that in Xuhuai, Ningzhenyang, and riverside agricultural areas. While the smallest number of nematodes was found in Yanjiang agricultural area (232 individuals per 100 g dry soil), which might be due to the differences in soil texture, annual rainfall and annual air temperature and other factors. The dominant genera of nematodes were similar in the adjacent agricultural areas. Correlation analysis showed that there was a significant positive correlation between the number of soil nematodes and levels of soil nutrients (soil organic matter, total nitrogen, available nitrogen, available potassium and available phosphorus). Redundancy analysis (RDA) indicated the total nitrogen, available potassium and pH obviously affected some soil nematode genera. The analysis of spatial distribution characteristics of soil nematode community in farmland of Jiangsu Province could provide data for health assessment of agricultural ecosystems. PMID:26915207

  15. Factors Controlling Nitrogen Fluxes in Groundwater in Agricultural Areas

    NASA Astrophysics Data System (ADS)

    Liao, L.; Green, C. T.; Bekins, B. A.; Bohlke, J. K.

    2010-12-01

    Predictions of effects of land use changes on water quality require identification of the relative importance of geochemical and hydrologic factors. To understand the factors controlling the transport of nitrogen in groundwater, vertical fluxes of water and solutes were estimated for 13 aquifers in agricultural areas located in California, Iowa, Maryland, Minnesota, Mississippi, Nebraska, North Carolina, Texas, and Wisconsin. The aquifers are overlain by unsaturated zones with thicknesses ranging from 2.5 to 100 m. Precipitation ranges from 19 to 132 cm/yr and irrigation ranges from 0 to 120 cm/yr. Main crop types include corn, soybeans, forage, wheat, and cotton. A 1-dimensional mathematical model was developed to estimate vertical N transport in response to N inputs on the land surface from chemical fertilizer, manure and atmospheric deposition. Simulated vertical profiles of O2, NO3-, N2 from denitrification, Cl- and atmospheric age tracers were matched to observations by adjusting parameters for recharge rate, unsaturated zone travel time, N leaching ratio (defined as leaching fraction of N reaching water table of N input at land surface), Cl- leaching ratio, O2 reduction rate and denitrification rate. Results indicated that vertical NO3 fluxes below the water table were affected by both geochemical and physical factors. High vertical NO3 fluxes below the water table are associated with high N input at the land surface. Values of Cl- leaching ratios were less than 1 (0.42 to 1) likely as a result of runoff and exported harvested crops. N leaching ratios were lower (0.1 to 0.6), consistent with additional N losses such as denitrification and volatilization. The sites with high leaching ratios for both N and Cl tended to be those with high recharge rates and low ET loss, defined as the fraction of applied water lost to ET. Modeled zero-order denitrification rates in the saturated zone varied within an order of magnitude with a maximum rate of 1.6 mg

  16. Carbon balance of sugarcane agriculture on histosols of the everglades agricultural area: review, analysis, and global energy perspectives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biofuels production from crop products and cellulosic by-products, including sugarcane, has received much attention. In Florida, most sugarcane is produced on drained Histosols (organic soils) of the Everglades Agricultural Area (EAA). Subsidence has occurred via microbial oxidation since drainage i...

  17. Pesticides in dust from homes in an agricultural area.

    PubMed

    Harnly, Martha E; Bradman, Asa; Nishioka, Marcia; McKone, Thomas E; Smith, Daniel; McLaughlin, Robert; Kavanagh-Baird, Geri; Castorina, Rosemary; Eskenazi, Brenda

    2009-12-01

    We collected indoor dust samples from homes in the Salinas Valley of California. Of 22 pesticides measured in 504 samples, permethrins and the organophosphate chlorpyrifos were present in highest amounts. In multivariate Tobit regression models among samples from 197 separate residences, reported agricultural uses of chlorpyrifos, a herbicide (2,3,5,6-tetrachloroterephthalate (DCPA)), and a fungicide (iprodione) on agricultural fields were significantly (p < 0.01) associated, with 83%, 19%, and 49% increases, respectively, in dust concentrations for each kg applied per day, near participant homes, in the month or season prior to sample collection. However, agricultural use of diazinon, which was 2.2 times that of chlorpyrifos, and of permethrin were not significantly associated with dust levels. Other variables independently associated with dust levels included temperature and rainfall, farmworkers storing work shoes in the home, storing a diazinon product in the home, housing density, having a home less clean, and having an air conditioner. Permethrins, chlorpyrifos, DCPA, and iprodione have either a log octanol-water partition coefficient (K(ow)) greater than 4.0, a very low vapor pressure, or both. Health risk assessments for pesticides that have these properties may need to include evaluation of exposures to house dust.

  18. Pesticides in dust from homes in an agricultural area.

    PubMed

    Harnly, Martha E; Bradman, Asa; Nishioka, Marcia; McKone, Thomas E; Smith, Daniel; McLaughlin, Robert; Kavanagh-Baird, Geri; Castorina, Rosemary; Eskenazi, Brenda

    2009-12-01

    We collected indoor dust samples from homes in the Salinas Valley of California. Of 22 pesticides measured in 504 samples, permethrins and the organophosphate chlorpyrifos were present in highest amounts. In multivariate Tobit regression models among samples from 197 separate residences, reported agricultural uses of chlorpyrifos, a herbicide (2,3,5,6-tetrachloroterephthalate (DCPA)), and a fungicide (iprodione) on agricultural fields were significantly (p < 0.01) associated, with 83%, 19%, and 49% increases, respectively, in dust concentrations for each kg applied per day, near participant homes, in the month or season prior to sample collection. However, agricultural use of diazinon, which was 2.2 times that of chlorpyrifos, and of permethrin were not significantly associated with dust levels. Other variables independently associated with dust levels included temperature and rainfall, farmworkers storing work shoes in the home, storing a diazinon product in the home, housing density, having a home less clean, and having an air conditioner. Permethrins, chlorpyrifos, DCPA, and iprodione have either a log octanol-water partition coefficient (K(ow)) greater than 4.0, a very low vapor pressure, or both. Health risk assessments for pesticides that have these properties may need to include evaluation of exposures to house dust. PMID:19943644

  19. Zr(IV) loaded cross-linked chitosan beads with enhanced surface area for the removal of nitrate and phosphate.

    PubMed

    Sowmya, Appunni; Meenakshi, Sankaran

    2014-08-01

    In this work, a new method namely silica dissolution method, has been adapted to increase the surface area of the cross-linked chitosan beads. Zr(IV) was loaded in the cross-linked chitosan beads in order to make it selective for the nitrate and phosphate anions from aqueous solutions. Zr(IV) loaded cross-linked chitosan beads prepared by normal method (ZrCB) and silica dissolution method (SD-ZrCB) were characterised using N2 adsorption/desorption studies, SEM, EDAX, XRD, FTIR, TGA, DTA and water regain property. The SD-ZrCB exhibited higher N2 adsorption, water regain property as well as anion adsorption capacity than ZrCB. Batch method was adapted for the adsorption studies. The nitrate and phosphate adsorbed SD-ZrCB was regenerated using 0.025M NaCl solution. There was not much drop in adsorption capacities up to 10th regeneration cycle. Freundlich adsorption isotherm was the best fit adsorption isotherm among Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherms which have been used to fit the nitrate and phosphate adsorption data. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated in order to understand the nature of adsorption process.

  20. Limited occurrence of denitrification in four shallow aquifers in agricultural areas of the United States

    USGS Publications Warehouse

    Green, C.T.; Puckett, L.J.; Böhlke, J.K.; Bekins, B.A.; Phillips, S.P.; Kauffman, L.J.; Denver, J.M.; Johnson, H.M.

    2008-01-01

    The ability of natural attenuation to mitigate agricultural nitrate contamination in recharging aquifers was investigated in four important agricultural settings in the United States. The study used laboratory analyses, field measurements, and flow and transport modeling for monitoring well transects (0.5 to 2.5 km in length) in the San Joaquin watershed, California, the Elkhorn watershed, Nebraska, the Yakima watershed, Washington, and the Chester watershed, Maryland. Ground water analyses included major ion chemistry, dissolved gases, nitrogen and oxygen stable isotopes, and estimates of recharge date. Sediment analyses included potential electron donors and stable nitrogen and carbon isotopes. Within each site and among aquifer-based medians, dissolved oxygen decreases with ground water age, and excess N2 from denitrification increases with age. Stable isotopes and excess N2 imply minimal denitrifying activity at the Maryland and Washington sites, partial denitrification at the California site, and total denitrification across portions of the Nebraska site. At all sites, recharging electron donor concentrations are not sufficient to account for the losses of dissolved oxygen and nitrate, implying that relict, solid phase electron donors drive redox reactions. Zero-order rates of denitrification range from 0 to 0.14 ??mol N L-1d-1, comparable to observations of other studies using the same methods. Many values reported in the literature are, however, orders of magnitude higher, which is attributed to a combination of method limitations and bias for selection of sites with rapid denitrification. In the shallow aquifers below these agricultural fields, denitrification is limited in extent and will require residence times of decades or longer to mitigate modern nitrate contamination. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  1. Nitrate concentrations and fluxes in the River Thames, London UK 1868 to 2008: catchment-scale modelling of diffuse agricultural sources and groundwater response using the world's longest water quality time series

    NASA Astrophysics Data System (ADS)

    Howden, N. J.; Burt, T. P.; Worrall, F.; Mathias, S.; Whelan, M.

    2011-12-01

    This paper presents analyses of the world's longest water quality record: 140 years of monthly-average nitrate concentrations (1868 to 2008) and fluxes (1883 to 2008) for the River Thames north of London. We show how short- and long- term patterns in these time series are influenced by both climatic and anthropogenic pressures, in the case of the latter, particularly land use and land management practices. Climate change does not play a significant role in controlling annual average concentrations or fluxes, rather large-scale land conversions from permanent grassland to arable farming have created sustained diffuse sources of nitrate that have caused (almost four-fold) increases in concentrations and fluxes that persist for many decades after the initial changes. Our analyses of this unique time series highlight four areas of particular interest: (1) Despite several layers of regulation and source control, fluvial concentrations and fluxes remain in- tractably high - no decrease has been observed since the early 1970s; (2) Catchment response to changing nitrogen inputs from land use and land management is subject to considerable lag: present conditions in the river reflect land practices from some years ago; (3) Following (2), we suggest that current changes to land use and land management practices will not be reflected in river water quality for some time to come; (4) Overall, the long-term view afforded by this record questions the derivation of "baseline conditions" that are formulated from records that do not reflect the massive changes in land use and land management in the mid-20th century. Overall, a better understanding of the links, and time delays, between cause (i.e. changing land use / land management) and fluvial response (i.e. concentration increase/decrease) will improve our ability both to predict changes in the coming decades, and inform management decision making now, to ensure the appropriate balance between agricultural development and

  2. Ground-water quality and vulnerability to contamination in selected agricultural areas of southeastern Michigan, northwestern Ohio, and northeastern Indiana

    USGS Publications Warehouse

    Thomas, Mary Ann

    2000-01-01

    Ground-water quality was assessed in the northeastern part of the Corn Belt, where tile-drained row crops are underlain by fractured glacial till. Data were collected from 30 shallow monitor wells and 18 co-located domestic wells as part of the U.S. Geological Survey?s National Water-Quality Assessment in the Lake Erie-Lake St. Clair Basin. Pesticides or pesticide degradates were detected in 41 percent of the monitor wells and 6 percent of the domestic wells. The pesticides detected closely correspond to those most heavily applied?herbicides used on corn and soybeans. Pesticide degradates were detected three times more frequently, and at higher concentrations, than were parent compounds. No pesticide concentration exceeded a USEPA Maximum Contaminant Level (MCL), but MCL?s have not been established for 9 of the 11 compounds detected. Thirty-seven percent of monitor-well samples had nitrate concentrations indicative of human influences such as fertilizer, manure or septic systems. Nitrate was the only chemical constituent detected at a concentration greater than an MCL. The MCL was exceeded in 7 percent of samples from monitor wells which were too shallow to be used as a source of drinking water. Pesticide and nitrate concentrations in the study area are low relative to other agricultural areas of the Nation. Several authors have suggested that ground water in parts of the Upper Mid-west is minimally contaminated because it is protected by the surficial glacial till or tile drains. These ideas are examined in light of the relations between concentration, well depth, and ground-water age in the study area. Most of the shallow ground water is hydraulically connected to the land surface, based on the observations that 83 percent of waters from monitor wells were recharged after 1953, and 57 percent contained a pesticide or an elevated nitrate concentration. Fractures or sand-and-gravel stringers within the till are the probable pathways. In some areas, deeper parts of

  3. Migrant and Seasonal Agricultural Areas. Methodology for Designating High Impact.

    ERIC Educational Resources Information Center

    HCR, Washington, DC.

    This report describes a method to estimate the number of migrant and seasonal farmworkers present in a prescribed area during crop harvest, and to pinpoint areas of high need for health and social services. The collection of health clinic and federal program data on migrant and seasonal farmworkers in Florida, northwestern Ohio, and Maryland's…

  4. Remote sensing for detection of soil limitations in agricultural areas

    NASA Technical Reports Server (NTRS)

    Frazee, C. J.; Heil, R. D.; Westin, F. C.

    1970-01-01

    Automatic analysis of soil limitations studied by an automatic color TV density slicing system was accomplished. This system color codes the density range of the value component of color of an image. Maps of soil limitations or other similar soil groups are produced by photographing the color coded representation of an area. The planimeter feature of the density slicing system measures the area of each soil limitation providing information on the importance of a soil limitation in an area. The results of this study suggest that an automatic color TV density slicing system has great potential not only for identifying and mapping similar soil areas, but also for indicating the percentage composition of an area.

  5. Nitrogen fertilizer rate and crop management effects on nitrate leaching from an agricultural field in central Pennsylvania.

    PubMed

    Fox, R H; Zhu, Y; Toth, J D; Jemison, J M; Jabro, J D

    2001-10-01

    Eighteen pan lysimeters were installed at a depth of 1.2 m in a Hagerstown silt loam soil in a corn field in central Pennsylvania in 1988. In 1995, wick lysimeters were also installed at 1.2 m depth in the same access pits. Treatments have included N fertilizer rates, use of manure, crop rotation (continuous corn, corn-soybean, alfalfa-corn), and tillage (chisel plow-disk, no-till). The leachate data were used to evaluate a number of nitrate leaching models. Some of the highlights of the 11 years of results include the following: 1) growing corn without organic N inputs at the economic optimum N rate (EON) resulted in NO3--N concentrations of 15 to 20 mg l(-1) in leachate; 2) use of manure or previous alfalfa crop as partial source of N also resulted in 15 to 20 mg l(-1) of NO3--N in leachate below corn at EON; 3) NO3--N concentration in leachate below alfalfa was approximately 4 mg l(-1); 4) NO3--N concentration in leachate below soybeans following corn was influenced by fertilizer N rate applied to corn; 5) the mass of NO3--N leached below corn at the EON rate averaged 90 kg N ha(-1) (approx. 40% of fertilizer N applied at EON); 6) wick lysimeters collected approximately 100% of leachate vs. 40-50% collected by pan lysimeters. Coefficients of variation of the collected leachate volumes for both lysimeter types were similar; 7) tillage did not markedly affect nitrate leaching losses; 8) tested leaching models could accurately predict leachate volumes and could be calibrated to match nitrate leaching losses in calibration years, but only one model (SOILN) accurately predicted nitrate leaching losses in the majority of validation treatment years. Apparent problems with tested models: there was difficulty estimating sizes of organic N pools and their transformation rates, and the models either did not include a macropore flow component or did not handle macropore flow well.

  6. NONFARM AGRICULTURAL EMPLOYMENT IN SOUTHEAST LOUISIANA--AREA IV--WITH IMPLICATIONS FOR DEVELOPING TRAINING PROGRAMS.

    ERIC Educational Resources Information Center

    MONDART, C.L., SR.; AND OTHERS

    AS PART OF A STATEWIDE STUDY OF AGRICULTURAL OCCUPATIONS IN LOUISIANA, AN INTERVIEW SURVEY OF 207 FARM-BASED FIRMS IN THE SOUTHEASTERN AREA, EXCLUDING BATON ROUGE AND NEW ORLEANS, WAS CONDUCTED TO DETERMINE (1) THE IDENTITY OF BUSINESSES AND ORGANIZATIONS HAVING EMPLOYEES WHO NEEDED AGRICULTURAL COMPETENCIES, (2) INFORMATION ABOUT JOBS, AND (3)…

  7. Quality of ground water in shallow wells in agricultural areas of Haywood, Shelby, Lake, and Obion counties, Tennessee, January and February 1988

    USGS Publications Warehouse

    Withington, D.B.

    1988-01-01

    Three areas with sparse data on the impact of agricultural chemicals on groundwater quality in the state of Tennessee were chosen for sampling groundwater for nitrogen species and pesticides. These sites, located in Haywood, Shelby, and Lake Counties, are all areas of high intensity agriculture. Because of the importance of the surficial alluvial aquifer to the domestic supply in West Tennessee, shallow wells at each site were sampled. Two sampling events were scheduled, in the winter and in the spring, to establish the difference between background and effected contaminant levels. Preliminary results from the first sampling event indicate a range of nitrite plus nitrate as nitrogen concentrations from less than 0.1 to 7.8 milligrams per liter. The results from triazine analyses show concentrations below the detection limit. (USGS)

  8. Biomonitors of stream quality on agricultural areas: fish versus invertebrates

    USGS Publications Warehouse

    Berkman, Hilary E.; Rabeni, Charles F.; Boyle, Terence P.

    1986-01-01

    Although the utility of using either fish or benthic invertebrates as biomonitors of stream quality has been clearly shown, there is little comparative information on the usefulness of the groups in any particular situation. We compared fish to invertebrate assemblages in their ability to reflect habitat quality of sediment-impacted streams in agricultural regions of northeast Missouri, USA. Habitat quality was measured by a combination of substrate composition, riparian type, buffer strip width, and land use. Invertebrates were more sensitive to habitat differences when structural measurements, species diversity and ordination, were used. Incorporating ecological measurements, by using the Index of Biological Integrity, increased the information obtained from the fish assemblage. The differential response of the two groups was attributed to the more direct impact of sediments on invertebrate life requisites; the impact of sedimentation on fish is considered more indirect and complex, affecting feeding and reproductive mechanisms.

  9. Digital spatial data for predicted nitrate and arsenic concentrations in basin-fill aquifers of the Southwest Principal Aquifers study area

    USGS Publications Warehouse

    McKinney, Tim S.; Anning, David W.

    2012-01-01

    This product "Digital spatial data for predicted nitrate and arsenic concentrations in basin-fill aquifers of the Southwest Principal Aquifers study area" is a 1:250,000-scale vector spatial dataset developed as part of a regional Southwest Principal Aquifers (SWPA) study (Anning and others, 2012). The study examined the vulnerability of basin-fill aquifers in the southwestern United States to nitrate contamination and arsenic enrichment. Statistical models were developed by using the random forest classifier algorithm to predict concentrations of nitrate and arsenic across a model grid that represents local- and basin-scale measures of source, aquifer susceptibility, and geochemical conditions.

  10. Arsenic, nitrate, iron, and hardness in ground water, Chena Hot Springs Road, Steele Creek Road, and Gilmore Trail areas, (T.1N., R.1E., FM), Fairbanks, Alaska

    USGS Publications Warehouse

    Krumhardt, Andrea P.

    1982-01-01

    This report presents all data on arsenic, nitrate, iron, and hardness in well water in the Chena Hot Springs Road, Steele Creek Road, and Gilmore Trail area of Fairbanks, Alaska, collected through October 1981. Concentrations range as follows: arsenic - 0 to 5,100 micrograms per liter; nitrate - 0 to 53 milligrams per liter; iron - 0 to 50 milligrams per liter, and hardness - 12 to 1,000 milligrams per liter. The percentage of samples exceeding limits set by the U.S. Environmental Protection Agency are as follows: arsenic - 13%; nitrate - 14%, and iron - 80%. (USGS)

  11. Adaptation of cytochrome-b5 reductase activity and methaemoglobinaemia in areas with a high nitrate concentration in drinking-water.

    PubMed Central

    Gupta, S. K.; Gupta, R. C.; Seth, A. K.; Gupta, A. B.; Bassin, J. K.; Gupta, A.

    1999-01-01

    An epidemiological investigation was undertaken in India to assess the prevalence of methaemoglobinaemia in areas with high nitrate concentration in drinking-water and the possible association with an adaptation of cytochrome-b5 reductase. Five areas were selected, with average nitrate ion concentrations in drinking-water of 26, 45, 95, 222 and 459 mg/l. These areas were visited and house schedules were prepared in accordance with a statistically designed protocol. A sample of 10% of the total population was selected in each of the areas, matched for age and weight, giving a total of 178 persons in five age groups. For each subject, a detailed history was documented, a medical examination was conducted and blood samples were taken to determine methaemoglobin level and cytochrome-b5 reductase activity. Collected data were subjected to statistical analysis to test for a possible relationship between nitrate concentration, cytochrome-b5 reductase activity and methaemoglobinaemia. High nitrate concentrations caused methaemoglobinaemia in infants and adults. The reserve of cytochrome-b5 reductase activity (i.e. the enzyme activity not currently being used, but which is available when needed; for example, under conditions of increased nitrate ingestion) and its adaptation with increasing water nitrate concentration to reduce methaemoglobin were more pronounced in children and adolescents. PMID:10534899

  12. Arsenic, nitrate, iron, and hardness, in ground water, Goldstream Road, Yankovich Road, and Murphy Dome Road areas (T.1 N, R.2 W, FM), Fairbanks, Alaska

    USGS Publications Warehouse

    Hopkins, Gary C.; Maxwell, Kevin F.

    1985-01-01

    Arsenic, nitrate, iron, and hardness in well water are concerns of homeowners and planners in the Fairbanks North Star Borough, Alaska. Arsenic and nitrate in water may affect human health. Iron and hardness can be aesthetically objectionable, impair plumbing systems, and discolor plumbing fixtures. This report is a compilation of the arsenic, nitrate, iron, and hardness data collected through February 1983 in the Goldstream Road, Murphy Dome Road, and Yankovich-Miller Hill Road areas of Fairbanks. Within these areas, concentrations of arsenic ranged from 0 to 1600 micrograms per liter, nitrate (as nitrogen) ranged from 0 to 78 milligrams per liter, iron ranged from 0 to 46 milligrams per liter, and hardness (as calcium carbonate) ranged from 34 to 1220 milligrams per liter. (USGS)

  13. Benthic invertebrates of benchmark streams in agricultural areas of eastern Wisconsin, Western Lake Michigan Drainages

    USGS Publications Warehouse

    Rheaume, S.J.; Lenz, B.N.; Scudder, B.C.

    1996-01-01

    Information gathered from these benchmark streams can be used as a regional reference for comparison with other streams in agricultural areas, based on communities of aquatic biota, habitat, and water quality.

  14. A new emission-based approach for regulation of N losses from agricultural areas to surface waters

    NASA Astrophysics Data System (ADS)

    Rosenstand Poulsen, Jane; Kronvang, Brian; Bering Ovesen, Niels; Piil, Kristoffer; Kolind Hvid, Søren

    2015-04-01

    Demands for a reduction and hence regulation of nitrogen (N) emissions to streams, lakes and coastal areas are a central part of many river basin management plans under the EU Water Framework Directive. Therefore, large focus has been placed on exploring different mitigation options that can assist in reducing the N emission from agricultural areas. However, the spatial variability in landscape, geology and hydrology entails significant differences in the vulnerability of catchments to intense agricultural activities. Hence, if rigid regulations of N emissions are applied without considering this variability, it will not necessarily lead to an optimum balance between applied fertilisers, yields and loss of excess N to the surrounding surface waters. Therefore, the overall purpose of this pilot study is to develop a concept for regulation of nutrient emissions to surface waters based on a comprehensive stream monitoring design in order to measure the temporal and spatial transport of N at sub-catchment scale. The purpose of such a monitoring design is twofold: i) quantification of the actual N emissions from a given agricultural sub-catchment or even individual farms; ii) quantification at sub-catchment scale of nitrate retention that may ultimately lead to a more precise regulation of N emissions from agricultural areas to surface waters. In order to investigate down to which scale it is feasible to quantify N emissions to surface waters and to develop the best monitoring concept, three catchments subdivided into several sub-catchments in Denmark will be studied during the period 2014-2017. The catchments represent different landscapes and geological settings as well as three different hydrological regimes. In the three catchments, hydrometric stations have been established at the outlet of the drainage networks where continuous measurements are made of water stage. In addition daily water samples and weekly grab samples of water are taken and weekly discharge

  15. Stream buffer effectiveness in an agriculturally influenced area, southwestern Georgia: responses of water quality, macroinvertebrates, and amphibians.

    PubMed

    Muenz, Tara K; Golladay, Stephen W; Vellidis, George; Smith, Lora L

    2006-01-01

    To determine useful metrics for assessing stream water quality in the Southeastern Coastal Plain, we examined differences among two buffered and three unbuffered streams in an agricultural landscape in southwestern Georgia. Potential indicators included amphibian diversity and abundance, aquatic macroinvertebrate populations, riparian vegetative structure, water quality, and stream physical parameters. Variability among sites and treatments (buffered vs. unbuffered) existed, with sites in the same treatment as most similar, and disturbances from a nearby eroding gully strongly affecting one unbuffered site. Of the invertebrate metrics examined, percentages of clingers, Ephemeroptera-Plecoptera-Trichoptera (EPT), Elmidae (Coleoptera), Crustacea (Decapoda and Amphipoda), and dipterans were found to be possible indicators of stream health for perennial streams within this region. Overall, buffered sites showed higher percentages of sensitive invertebrate groups and showed lower and more stable concentrations of nitrate N, suspended solids, and fecal coliforms (FCs). Percent canopy cover was similar among sites; however, riparian vegetative coverage and percent leaf litter were greatest at buffered sites. No differences in amphibian abundance, presence, and absence within the riparian area were apparent between sites; however, instream larval salamanders were more abundant at buffered streams. In this study, stream buffers appeared to decrease nutrient and sediment loads to adjacent streams, enhancing overall water quality. Selected benthic macroinvertebrate metrics and amphibian abundance also appeared sensitive to agricultural influences. Amphibians show potential as indicator candidates, however further information is needed on their responses and tolerances to disturbances from the microhabitat to landscape levels.

  16. Leaching of dissolved phosphorus from tile-drained agricultural areas.

    PubMed

    Andersen, H E; Windolf, J; Kronvang, B

    2016-01-01

    We investigated leaching of dissolved phosphorus (P) from 45 tile-drains representing animal husbandry farms in all regions of Denmark. Leaching of P via tile-drains exhibits a high degree of spatial heterogeneity with a low concentration in the majority of tile-drains and few tile-drains (15% in our investigation) having high to very high concentration of dissolved P. The share of dissolved organic P (DOP) was high (up to 96%). Leaching of DOP has hitherto been a somewhat overlooked P loss pathway in Danish soils and the mechanisms of mobilization and transport of DOP needs more investigation. We found a high correlation between Olsen-P and water extractable P. Water extractable P is regarded as an indicator of risk of loss of dissolved P. Our findings indicate that Olsen-P, which is measured routinely in Danish agricultural soils, may be a useful proxy for the P leaching potential of soils. However, we found no straight-forward correlation between leaching potential of the top soil layer (expressed as either degree of P saturation, Olsen-P or water extractable P) and the measured concentration of dissolved P in the tile-drain. This underlines that not only the source of P but also the P loss pathway must be taken into account when evaluating the risk of P loss. PMID:27332841

  17. Rapid regional recovery from sulfate and nitrate pollution in streams of the western Czech Republic - Comparison to other recovering areas

    USGS Publications Warehouse

    Majer, V.; Kram, P.; Shanley, J.B.

    2005-01-01

    Hydrochemical changes between 1991 and 2001 were assessed based on two synoptic stream surveys from the 820-km2 region of the Slavkov Forest and surrounding area, western Czech Republic. Marked declines of sulfate, nitrate, chloride, calcium and magnesium in surface waters were compared with other areas of Europe and North America recovering from acidification. Declines of sulfate concentration in the Slavkov Forest (-30 ??eq L-1 yr-1) were more dramatic than declines reported from other sites. However, these dramatic declines of strong acid anions did not generate a widespread increase of stream water pH in the Slavkov Forest. Only the most acidic streams experienced a slight increase of pH by 0.5 unit. An unexpected decline of stream water pH occurred in slightly alkaline streams. ?? 2004 Elsevier Ltd. All rights reserved.

  18. Effects of low-grade weirs on soil microbial communities to advance agricultural best management practices for nitrate remediation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural activities throughout the Mississippi River Basin have been identified as a major source of nutrient pollution, particularly nitrogen from fertilizer application, to downstream waters including the Gulf of Mexico. Utilizing best management practices, such as low-grade weirs have been id...

  19. HYDROGEOLOGIC FOUNDATION IN SUPPORT OF ECOSYSTEM RESTORATION: BASE-FLOW LOADINGS OF NITRATE IN MID-ATLANTIC AGRICULTURAL WATERSHEDS

    EPA Science Inventory

    The study is a consortium between the U.S. Environmental Protection Agency (National Risk Management Research Laboratory) and the U.S. Geological Survey (Baltimore and Dover). The objectives of this study are: (1) to develop a geohydrological database for paired agricultural wate...

  20. Risk assessment of surface water and groundwater pollution through agricultural activity on the catchment area of the Shelek River

    NASA Astrophysics Data System (ADS)

    Zubairov, Bulat; Dautova, Assel

    2015-04-01

    Agricultural activity in rural areas of Kazakhstan can create a potential risk of surface and groundwater pollution. In our contribution, we will focus on the risk assessment of surface water and groundwater pollution in the catchment area of the Shelek River basin in southeast Kazakhstan. Since soviet time, in the research area an intensive cultivation of tobacco was performed which means to use a big amount of pesticides during the growing-process. Therefore, this research was conducted in order to receive reliable data for management decisions justification and for practical testing of approach which is recommended by WHO for drinking water supply based on risks mapping. For our study, the soil and water samples from tobacco fields, artesian spring, and surface water source were taken for analysis on pesticides content. The samples were investigated in laboratory of Centre of Sanitary and Epidemiological Expertise of Almaty city (CSEE) according to approved methods from the national standards which are accepted in Kazakhstan. For the first time, in artesian spring small amount of nitrate pollution was found whose groundwater is one of the drinking water supplies of the region.

  1. Occurrence of nitrate and pesticides in ground water beneath three agricultural land-use settings in the eastern San Joaquin Valley, California, 1993-1995

    USGS Publications Warehouse

    Burow, Karen R.; Shelton, Jennifer L.; Dubrovsky, Neil M.

    1998-01-01

    The processes that affect nitrate and pesticide occurrence may be better understood by relating ground-water quality to natural and human factors in the context of distinct, regionally extensive, land- use settings. This study assesses nitrate and pesticide occurrence in ground water beneath three agricultural land-use settings in the eastern San Joaquin Valley, California. Water samples were collected from 60 domestic wells in vineyard, almond, and a crop grouping of corn, alfalfa, and vegetable land-use settings. Each well was sampled once during 1993?1995. This study is one element of the U.S. Geological Survey?s National Water-Quality Assessment Program, which is designed to assess the status of, and trends in, the quality of the nation?s ground- and surface-water resources and to link the status and trends with an understanding of the natural and human factors that affect the quality of water. The concentrations and occurrence of nitrate and pesticides in ground-water samples from domestic wells in the eastern alluvial fan physiographic region were related to differences in chemical applica- tions and to the physical and biogeochemical processes that charac- terize each of the three land-use settings. Ground water beneath the vineyard and almond land-use settings on the coarse-grained, upper and middle parts of the alluvial fans is more vulnerable to nonpoint- source agricultural contamination than is the ground water beneath the corn, alfalfa, and vegetable land-use setting on the lower part of the fans, near the basin physiographic region. Nitrate concentrations ranged from less than 0.05 to 55 milligrams per liter, as nitrogen. Nitrate concentrations were significantly higher in the almond land-use setting than in the vineyard land-use setting, whereas concentrations in the corn, alfalfa, and vegetable land-use setting were intermediate. Nitrate concentrations exceeded the maximum contaminant level in eight samples from the almond land- use setting (40

  2. Potential endocrine disruption of sexual development in free ranging male northern leopard frogs (Rana pipiens) and green frogs (Rana clamitans) from areas of intensive row crop agriculture.

    PubMed

    McDaniel, Tana V; Martin, Pamela A; Struger, John; Sherry, Jim; Marvin, Chris H; McMaster, Mark E; Clarence, Stacey; Tetreault, Gerald

    2008-07-30

    Intensive row crop agriculture (IRCA) for corn and soybean production is predominant in eastern and central North America. IRCA relies heavily on pesticide and nutrient inputs to maximize production under conventional systems. In 2003-2005, we assessed the occurrence of a suite of potential endocrine effects in amphibians inhabiting farm ponds and agricultural drains in IRCA areas of southwestern Ontario. Effects were compared to amphibians from two agricultural reference sites as well as four non-agricultural reference sites. Pesticide and nutrient concentrations were also determined in water samples from those sites. Atrazine and metolachlor were detected in most samples, exceeding 1 microg L(-1) at some sites. Blood samples were taken from northern leopard frogs (Rana pipiens) and green frogs (Rana clamitans) for analysis of circulating sex steroids and vitellogenin-like protein (Vtg-lp), a biomarker of exposure to environmental estrogens. Gonads were histologically examined for evidence of abnormalities. Some evidence of exposure to endocrine disrupting compounds was apparent from the data. The occurrence of testicular ovarian follicles (TOFS) in male R. pipiens was significantly higher (42%; p<0.05) at agricultural sites, particularly those in Chatham county compared to frogs from reference sites (7%). There was no difference in circulating sex steroid levels between frogs from agricultural and reference sites and sex steroid levels did not correlate with pesticide concentrations in the environment. No differences were detected in the gonadosomatic indices or stage of spermatogenesis between frogs from agricultural and non-agricultural regions (p>0.05). Plasma Vtg-lp was detected in only one male R. pipiens from an agricultural site. Neither gonad size, gonad maturity nor sex steroid levels differed between normal males and those with testicular oocytes. Although the proportion of testicular oocytes did not correlate directly with atrazine concentrations, it

  3. An unexpected truth: increasing nitrate loading can decrease nitrate export from watersheds

    NASA Astrophysics Data System (ADS)

    Askarizadeh Bardsiri, A.; Grant, S. B.; Rippy, M.

    2015-12-01

    The discharge of anthropogenic nitrate (e.g., from partially treated sewage, return flows from agricultural irrigation, and runoff from animal feeding operations) to streams can negatively impact both human and ecosystem health. Managing these many point and non-point sources to achieve some specific end-point—for example, reducing the annual mass of nitrate exported from a watershed—can be a challenge, particularly in rapidly growing urban areas. Adding to this complexity is the fact that streams are not inert: they too can add or remove nitrate through assimilation (e.g., by stream-associated plants and animals) and microbially-mediated biogeochemical reactions that occur in streambed sediments (e.g., respiration, ammonification, nitrification, denitrification). By coupling a previously published correlation for in-stream processing of nitrate [Mulholland et al., Nature, 2008, 452, 202-205] with a stream network model of the Jacksons Creek watershed (Victoria, Australia) I demonstrate that managing anthropogenic sources of stream nitrate without consideration of in-stream processing can result in a number of non-intuitive "surprises"; for example, wastewater effluent discharges that increase nitrate loading but decrease in-stream nitrate concentrations can reduce the mass of nitrate exported from a watershed.

  4. Is the measurement of the isotopic composition of nitrate a good tool for tracing sources of nitrate in groundwater?

    NASA Astrophysics Data System (ADS)

    Sebilo, Mathieu

    2014-05-01

    Isotopic biogeochemistry allows tracing of nitrogen sources in the environment. The dual approach i.e 15N and 18O approach has been used for decades to determine the origin of nitrate in surface and groundwater. The isotopic composition of fertilizers differs for example significantly from that of nitrate in atmospheric deposition and nitrate produced by nitrification. A long term study (30 years) based on the use of lysimeters and 15N labelled nitrate showed that nitrate which is not immediately taken up by plants is assimilated into the organic matter pool. This pool produces nitrate, with an isotopic signature of 'newly produced nitrate' and different from its origin (1). Based on this study, the natural stable isotopic composition of nitrate (δ18O-NO3-andδ15N-NO3-)was measured in water samples collected below the root zone or in aquifers from the Seine River basin. We compared these with the isotopic composition of nitrate from synthetic fertilizers and atmospheric deposition which represent the most significant sources of nitrogen in these systems. In addition, the δ15N of the organic matter pool in cultivated soils from this area was analyzed. The δ18O-NO3-results show clearly that nitrate issued from highly fertilized agricultural soils are freshly produced through nitrification of reduced nitrogen in the soil, instead of being directly transferred through the soil profile from applied fertilizers, indicating the major role of the soil organic matter pool. Our results thus bring new insights in the understanding of nitrogen contamination of surface and groundwater from agricultural watersheds, emphasizing the role of soil organic matter as a buffer. (1). Sebilo M., Nicolardot B., Mayer B., Pinay G. & Mariotti A. (2013). Long-term fate of nitrate fertilizer in agricultural soils. PNAS. 110 (45) : 18185-18189. doi/10.1073/pnas.1305372110.

  5. Mercury Cycling in Agricultural and Non-agricultural Wetlands of the Yolo Bypass Wildlife Area, California: Sediment Biogeochemistry

    NASA Astrophysics Data System (ADS)

    Marvin-Dipasquale, M. C.; Windham-Myers, L.; Alpers, C. N.; Agee, J. L.; Cox, M. H.; Kakouros, E.; Wren, S. L.

    2007-12-01

    The Yolo Bypass Wildlife Area (YBWA) is part of the larger Yolo Bypass floodwater protection zone associated with the Sacramento River and the Sacramento-San Joaquin Delta, California. Land use in the YBWA consists of white and wild rice fields, seasonally flooded fallow agricultural fields, and permanently and seasonally flooded non-agricultural wetlands used for resident and migratory waterfowl. A recent assessment of mercury (Hg) and methylmercury (MeHg) loads indicates that the Yolo Bypass is responsible for a high proportion of the aqueous MeHg entering the Delta, and that biota from the Yolo Bypass are considerably elevated in MeHg. The current study examines benthic MeHg production and biogeochemical controls on this process, as a function of YBWA land use, wetland management, and agricultural practices during the 2007 rice growing season (June to October). Preliminary results indicate that in the week following initial flooding of agricultural fields, prior to the establishment of rice plants, the microbial community in the 0-2 cm surface sediment zone exhibited very little potential Hg(II)-methylation activity compared to the permanent wetland habitat (as assessed via the 203Hg(II)- methylation assay). Approximately 1 month after flooding, rice plants were established and the activity of the resident Hg(II)-methylating microbial community had increased substantially in all agricultural fields, although the observed rates of MeHg production were still much lower than those observed in the permanent wetland setting. Ongoing field sampling includes analysis of reactive Hg(II) in sediments and of iron and sulfur redox species in sediments and pore waters.

  6. Linking soil water balance and water age with leaching of nitrate to groundwater in an agricultural setting

    NASA Astrophysics Data System (ADS)

    Sigler, W.; Ewing, S. A.; Payn, R. A.; Jones, C. A.; Weissmann, G. S.

    2013-12-01

    The effects of land management on groundwater chemistry are often poorly understood due to uncertainties about residence times of water and solutes in the unsaturated and the saturated zones. In central Montana, a strath terrace mantled with 20-100 cm of loess-derived clay loam is composed of 5-10 meters of gravel hosting a shallow aquifer overlying shale. The landform is isolated from mountain front stream recharge and drained by springs at the gravel/shale interface surrounding the terrace. Ninety three percent of the terrace surface is cultivated, predominantly for production of small grains. A typical cropping system on the terrace is a three year rotation of winter wheat, spring wheat or barley, and fallow, where each phase represents a different regime of evapotranspiration, recharge, fertilizer application, mineralization and nitrate leaching to groundwater. Age of water in discharge from the perched aquifer in the gravel can potentially be characterized by monitoring springs and streams that are ultimately sourced by infiltration and recharge across the terrace. Work presented here couples a simple daily soil water balance model with ground and surface water chemistry to infer travel times through the unsaturated and saturated zones. These results are evaluated against estimates of groundwater age derived from pool turnover time calculations, finite difference groundwater flow modeling, and use of chemical age tracers.

  7. Redox reaction rates in shallow aquifers: Implications for nitrate transport in groundwater and streams

    USGS Publications Warehouse

    Tesoriero, Anthony J.

    2012-01-01

    Groundwater age and water chemistry data along flow paths from recharge areas to streams were used to evaluate the trends and transformations of agricultural chemicals. Results from this analysis indicate that median nitrate recharge concentrations in these agricultural areas have increased markedly over the last 50 years from 4 mg N/L in samples collected prior to 1983 to 7.5 mg N/L in samples collected since 1983. The effect that nitrate accumulation in shallow aquifers will have on drinking water quality and stream ecosystems is dependent on the rate of redox reactions along flow paths and on the age distribution of nitrate discharging to supply wells and streams.

  8. Net Exchange Ecossistem in Subtropical Agriculture Area in Southern Brazil

    NASA Astrophysics Data System (ADS)

    Roberti, D. R.; Diaz, M.; Webler, G.; Fiorin, J.; de Moraes, O. L. L.; Teichrieb, C.; Amado, T.

    2015-12-01

    Southern Brazil contribute to 38% of Brazilian grain production. In contrast with the rest of the country, the south has a wet, subtropical climate that permits two annual harvests (double cropping system). The soybean and/or maize (summer) and black oat and/or wheat (winter) succession is widely used by farmers in plateau areas. In river natural lowlands, the cultivation of flooded irrigated rice is common. Changes in the land use affect the carbon, water and energy balance, and crop management practices, such as fertilization, water management, harvest and crop residues have influence in carbon exchange between the crop field and the atmosphere. This study quantifies the net exchange ecosystem (NEE) between the atmosphere and the crop cultivations in this wide region of Brazil from 2010 to 2014. We use data from two micrometeorological sites: Cruz Alta, with crop rotation and Cachoeira do Sul, with rice paddy. The carbon flux was analyzed using the eddy covariance method and gap filling procedures. The annual integration of data carbon demonstrates that the agroecosystems in southern Brazil is a acting as an light atmospheric CO2 sink. However, the NEE emissions that occurred in the fallow periods contributed negatively for such annual accumulation. To reduce this loss of CO2, farmers could cultivate plants in fallow periods, because there are favorable weather conditions for growing plants year round. Additionally, other management practices can increase the influx of C, including the production of more dry matter with cover crops by improving management and the immediate harvesting of crop after physiological maturity to reduce the period between maturation and harvest.

  9. A Review of Non-occupational Pathways for Pesticide Exposure in Women Living in Agricultural Areas

    EPA Science Inventory

    Women living in agricultural areas may experience relatively high pesticide exposures compared to women in urban or suburban areas due to their proximity to farm activities. However, exposure pathways in these women are not well-characterized. We reviewed the evidence for the con...

  10. Nitrate in groundwater in the United States

    NASA Astrophysics Data System (ADS)

    Burow, K. R.; Nolan, B. T.; Rupert, M. G.; Dubrovsky, N. M.

    2009-12-01

    An assessment of nitrate concentrations in groundwater in the United States (US) indicates that concentrations are highest in shallow, oxic groundwater beneath areas with high nitrogen inputs. During 1991-2003, 5,101 wells were sampled in 51 study areas throughout the US as part of the USGS National Water-Quality Assessment program. Well locations for individual 30-well networks were selected for sampling using a computerized, stratified, random site-selection procedure to minimize spatial bias. These well networks reflect the existing used resource in major aquifers represented by domestic wells (major aquifer studies), and recently recharged groundwater beneath dominant land-surface activities (land-use studies). Nitrate concentrations in groundwater were compared with nationally-available variables such as nonpoint-source nitrogen inputs, soils, water chemistry, and other aquifer and well construction characteristics to predict the conditions most vulnerable to high nitrate concentrations. Nitrate was detected at concentrations above background of 1.0 mg/L (as N) in 50% of the wells sampled. Shallow groundwater beneath agricultural land had the highest median concentration of nitrate (3.1 mg/L). Median nitrate in shallow groundwater beneath urban land (1.4 mg/L) was lower than beneath agricultural land, but was higher than the median in major aquifers (0.56 mg/L). Although most wells sampled in the shallow land-use studies were not used for drinking water, concentrations exceeded the US EPA drinking-water standard (MCL) of 10 mg/L in 20% of wells in the agricultural land-use setting. Concentrations exceeded the MCL in only 3% of wells in the urban land-use setting, and 4% of wells in major aquifers. Classification and regression tree analysis was used to identify the relative importance of nitrogen inputs, water chemistry, and physical aquifer properties on nitrate concentrations in groundwater. Factors ranked by reduction in sum of squares indicate that

  11. Nitrate pollution and its distribution in the groundwater of Srikakulam district, Andhra Pradesh, India

    NASA Astrophysics Data System (ADS)

    Rao, Nagireddi Srinivasa

    2006-12-01

    The complex depositional pattern of clay and sand in most of the areas controlled the vertical and lateral movement of nitrate in groundwater. The variation of nitrate concentration at different groundwater levels and the lateral distribution of nitrate in the groundwater at two sites indicated the filtration of nitrate by clayey formations. A rural agricultural district located in the Vamsadhara river basin, India was selected for studying the lateral and vertical distribution of nitrate in the groundwater and the association of nitrate with other chemical constituents. The nitrate concentrations in the groundwater are observed to vary between below detectable limit and 450 mg NO3/L. The sources for nitrate are mainly point sources (poultry farms, cattleshed and leakages from septic tanks) and non-point sources (nitrogenous fertilisers). The nitrate concentrations are increased after fertiliser applications. However, very high concentrations of nitrate are derived from animal wastes. Relatively better correlations between nitrate and potassium are observed ( R = 0.74 to 0.82). The better relationship between these two chemical constituents in the groundwater may be due to the release of potassium and nitrate from both point and non-point sources. The nitrate and potassium concentrations are high in the groundwater from clayey formations.

  12. Assessment of nitrate concentration in groundwater in Saudi Arabia.

    PubMed

    Alabdula'aly, Abdulrahman I; Al-Rehaili, Abdullah M; Al-Zarah, Abdullah I; Khan, Mujahid A

    2010-02-01

    Contamination of groundwater by nitrate is considered a global problem. Nitrates are introduced in the groundwater from a variety of sources like agricultural activities, poor sewer system, wastewaters, and industrial activities. In the present research, a survey of wells (n = 1,060) was undertaken in all 13 regions of the Kingdom of Saudi Arabia to assess the contained nitrate (NO(3)) levels. The results indicated variation in nitrate levels from 1.1 to 884.0 mg/L as NO(3) throughout the Kingdom. The average nitrate levels in milligrams per liter as NO(3) were as follows in descending order: 65.7 (Jizan), 60.3 (Asir), 60.0 (Qassim), 51.3 (Hail), 41.8 (Makkah Al Mukaramma), 41.3 (Madina Al Munnawara), 38.0 (Al Baha), 37.0 (Najran), 30.7, (Tabouk), 25.2 (Eastern Province), 18.8 (Riyadh), 15.8 (Al Jouf), and 9.1 (Hadwed Shamalyah). The results indicated that nitrate levels exceeded the maximum contaminant limits for drinking water (45 mg/L as NO(3)) in a number of wells (n = 213) in different regions of the Kingdom. The maximum and minimum wells exceeding the maximum contaminant limits for nitrate in drinking water were in Jizan (52.6%) and Hadwed Shamalyah (4.9%), respectively. Most of the wells which exceeded the maximum allowed limits for nitrate were in the areas which were used for agricultural and residential purposes.

  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. Calibration and validation of an integrated nitrate transport model within a well capture zone.

    PubMed

    Bonton, Alexandre; Bouchard, Christian; Rouleau, Alain; Rodriguez, Manuel J; Therrien, René

    2012-02-01

    Groundwater contamination by nitrate was investigated in an agricultural area in southern Quebec, Canada, where a municipal well is the local source of drinking water. A network of 38 piezometers was installed within the capture zone of the municipal well to monitor water table levels and nitrate concentrations in the aquifer. Nitrate concentrations were also measured in the municipal well. A Water flow and Nitrate transport Global Model (WNGM) was developed to simulate the impact of agricultural activities on nitrate concentrations in both the aquifer and municipal well. The WNGM first uses the Agriflux model to simulate vertical water and nitrate fluxes below the root zone for each of the seventy agricultural fields located within the capture zone of the municipal well. The WNGM then uses the HydroGeoSphere model to simulate three-dimensional variably-saturated groundwater flow and nitrate transport in the aquifer using water and nitrate fluxes computed with the Agriflux model as the top boundary conditions. The WNGM model was calibrated by reproducing water levels measured from 2005 to 2007 in the network of piezometers and nitrate concentrations measured in the municipal well from 1997 to 2007. The nitrate concentrations measured in the network of piezometers, however, showed greater variability than in the municipal well and could not be reproduced by the calibrated model. After calibration, the model was validated by successfully reproducing the decrease of nitrate concentrations observed in the municipal well in 2006 and 2007. Although it cannot predict nitrate concentrations in individual piezometers, the calibrated and validated WNGM can be used to assess the impact of changes in agricultural practices on global nitrate concentrations in the aquifer and in the municipal well.

  15. A Review of Nonoccupational Pathways for Pesticide Exposure in Women Living in Agricultural Areas

    PubMed Central

    Friesen, Melissa C.; Hoppin, Jane A.; Hines, Cynthia J.; Thomas, Kent; Freeman, Laura E. Beane

    2015-01-01

    Background Women living in agricultural areas may experience high pesticide exposures compared with women in urban or suburban areas because of their proximity to farm activities. Objective Our objective was to review the evidence in the published literature for the contribution of nonoccupational pathways of pesticide exposure in women living in North American agricultural areas. Methods We evaluated the following nonoccupational exposure pathways: paraoccupational (i.e., take-home or bystander exposure), agricultural drift, residential pesticide use, and dietary ingestion. We also evaluated the role of hygiene factors (e.g., house cleaning, shoe removal). Results Among 35 publications identified (published 1995–2013), several reported significant or suggestive (p < 0.1) associations between paraoccupational (n = 19) and agricultural drift (n = 10) pathways and pesticide dust or biomarker levels, and 3 observed that residential use was associated with pesticide concentrations in dust. The 4 studies related to ingestion reported low detection rates of most pesticides in water; additional studies are needed to draw conclusions about the importance of this pathway. Hygiene factors were not consistently linked to exposure among the 18 relevant publications identified. Conclusions Evidence supported the importance of paraoccupational, drift, and residential use pathways. Disentangling exposure pathways was difficult because agricultural populations are concurrently exposed to pesticides via multiple pathways. Most evidence was based on measurements of pesticides in residential dust, which are applicable to any household member and are not specific to women. An improved understanding of nonoccupational pesticide exposure pathways in women living in agricultural areas is critical for studying health effects in women and for designing effective exposure-reduction strategies. Citation Deziel NC, Friesen MC, Hoppin JA, Hines CJ, Thomas K, Beane Freeman LE. 2015. A review

  16. Economic gains from targeted measures related to non-point pollution in agriculture based on detailed nitrate reduction maps.

    PubMed

    Jacobsen, Brian H; Hansen, Anne Lausten

    2016-06-15

    From 1990 to 2003, Denmark reduced N-leaching from the root zone by 50%. However, more measures are required, and in recent years, the focus has been on how to differentiate measures in order to ensure that they are implemented where the effect on N-loss reductions per ha is the greatest. The purpose of the NiCA project has been to estimate the natural nitrate reduction in the groundwater more precisely than before using a plot size down to 1ha. This article builds on these findings and presents the possible economic gains for the farmer when using this information to reach a given N-loss level. Targeted measures are especially relevant where the subsurface N-reduction varies significantly within the same farm and national analyses have shown that a cost reduction of around 20-25% using targeted measures is likely. The analyses show an increasing potential with increasing variation in N-reduction in the catchment. In this analysis, the knowledge of spatial variation in N-reduction potential is used to place measures like catch crops or set-a-side at locations with the greatest effect on 10 case farms in the Norsminde Catchment, Denmark. The findings suggest that the gains are from 0 to 32€/ha and the average farm would gain approximately 14-21€/ha/year from the targeted measures approach. The analysis indicates that the economic gain is greater than the costs of providing the detailed maps of 5-10€/ha/year. When N-loss reduction requirements are increased, the economic gains are greater. When combined with new measures like mini-wetlands and early sowing the economic advantage is increased further. The paper also shows that not all farms can use the detailed information on N-reduction and there is not a clear link between spatial variation in N-reduction at the farm level and possible economic gains for all these 10 farms. PMID:26974574

  17. Tolerance of developing salmonid eggs and fry to nitrate exposure

    USGS Publications Warehouse

    Kincheloe, John W.; Wedemeyer, Gary A.; Koch, David L.

    1979-01-01

    This paper reports on tests which show significant effects on early salmonid life stages of nitrates at levels commonly found in groundwaters in geographical areas that are influenced by fertilizer application. It has long been known, from fish cultural experience, that in certain site specific locations, chronic problems can be expected with salmonid egg development and early fry mortality. However, fingerlings which survive usually grow normally. A complete explanation is lacking although several environmental factors have been proposed to account for this phenomenon. One, which has so far received little attention, is that nitrate levels in the ground and surface waters of many areas have been increasing significantly over historical background levels. Ammonia, urea, and other potential sources of nitrate can enter natural waters from a variety of sources, such as domestic or industrial sewage, animal feedlots, or seepage and return flows from agricultural lands. The latter may be the largest contributor, since billions of tons of nitrate fertilizers are applied to agricultural crops on a worldwide basis each year. In addition, intensive forest management techniques include the aerial application of nitrate fertilizer to increase the yield of wood products, while range management practices call for use of nitrates to increase forage production. The nitrate that is not taken up by plants ultimately appears in ground or surface waters.

  18. 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.

  19. Pesticides in ground water in selected agricultural land-use areas and hydrogeologic settings in Pennsylvania, 2003-07

    USGS Publications Warehouse

    Loper, Connie A.; Breen, Kevin J.; Zimmerman, Tammy M.; Clune, John W.

    2009-01-01

    This report was prepared by the U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Agriculture (PDA) as part of the Pennsylvania Pesticides and Ground Water Strategy (PPGWS). Monitoring data and extensive quality-assurance data on the occurrence of pesticides in ground water during 2003–07 are presented and evaluated; decreases in the land area used for agriculture and corresponding changes in the use of pesticides also are documented. In the Pennsylvania ground waters assessed since 2003, concentrations of pesticides did not exceed any maximum contaminant or health advisory levels established by the U.S. Environmental Protection Agency; PPGWS actions are invoked by the PDA at fractions of these levels and were needed only in areas designated by the PDA for special ground-water protection. Previous investigations through 1998 of pesticides in Pennsylvania ground water identified land use, as a surrogate for pesticide use, and rock type of the aquifer combined with physiography as key hydrogeologic setting variables for understanding aquifer vulnerability to contamination and the common occurrence of atrazine and metolachlor in ground water. Of 20 major hydrogeologic settings in a framework established in 1999 for pesticide monitoring in Pennsylvania, 9 were identified as priorities for data collection in order to change the monitoring status from "inadequate" to "adequate" for the PPGWS. Agricultural and forested land-use areas are decreasing because of urban and suburban growth. In the nine hydrogeologic settings evaluated using 1992 and 2001 data, decreases of up to 12 percent for agricultural land and 10 percent for forested land corresponded to increases of up to 11 percent for urban land. Changes in agricultural pesticide use were computed from crop data. For example, from 1996 to 2004–05, atrazine use declined by about 15 percent to 1,314,000 lb/yr (pounds per year) and metolachlor use increased by about 20 percent to 895

  20. Sustaining Irrigated Agriculture in Arid Areas: Lessons Learned in the San Joaquin Valley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The conventional wisdom is that drainage is required to sustain irrigation in arid and semiarid areas. However, disposal of saline drainage water is a problem throughout the world that is challenging the sustainability of irrigated agriculture. The presence of elements besides salt in the drainage w...

  1. AGRICULTURAL MECHANICS INSTRUCTION IN SECONDARY SCHOOLS IN MISSISSIPPI, THE LABORATORY-WORK AREA APPROACH.

    ERIC Educational Resources Information Center

    POWELL, G.G., JR.; WALKER, G.M.

    TO MEET THE NEEDS RESULTING FROM INCREASED FARM MECHANIZATION, AN INTENSIFIED AND EXPANDED CURRICULUM IN AGRICULTURAL MECHANICS HAS BEEN PROPOSED COVERING--(1) FARM MACHINERY, (2) FARM BUILDINGS, (3) ELECTRICITY, (4) WELDING, (5) CONCRETE AND MASONRY, (6) PLUMBING, (7) METAL WORKING, AND (8) TOOL FITTING. DISCUSSION OF EACH OF THESE AREAS INCLUDES…

  2. Losses of Ammonia and Nitrate from Agriculture and Their Effect on Nitrogen Recovery in the European Union and the United States between 1900 and 2050.

    PubMed

    van Grinsven, Hans J M; Bouwman, Lex; Cassman, Kenneth G; van Es, Harold M; McCrackin, Michelle L; Beusen, Arthur H W

    2015-03-01

    Historical trends and levels of nitrogen (N) budgets and emissions to air and water in the European Union and the United States are markedly different. Agro-environmental policy approaches also differ, with emphasis on voluntary or incentive-based schemes in the United States versus a more regulatory approach in the European Union. This paper explores the implications of these differences for attaining long-term policy targets for air and water quality. Nutrient surplus problems were more severe in the European Union than in the United States during the 1970s and 1980s. The EU Nitrates and National Emission Ceilings directives contributed to decreases in fertilizer use, N surplus, and ammonia (NH) emissions, whereas in the United States they stabilized, although NH emissions are still increasing. These differences were analyzed using statistical data for 1900-2005 and the global IMAGE model. IMAGE could reproduce NH emissions and soil N surpluses at different scales (European Union and United States, country and state) and N loads in the Rhine and Mississippi. The regulation-driven changes during the past 25 yr in the European Union have reduced public concerns and have brought agricultural N loads to the aquatic environment closer to US levels. Despite differences in agro-environmental policies and agricultural structure (more N-fixing soybean and more spatially separated feed and livestock production in the United States than in the European Union), current N use efficiency in US and EU crop production is similar. IMAGE projections for the IAASTD-baseline scenario indicate that N loading to the environment in 2050 will be similar to current levels. In the United States, environmental N loads will remain substantially smaller than in the European Union, whereas agricultural production in 2050 in the United States will increase by 30% relative to 2005, as compared with an increase of 8% in the European Union. However, in the United States, even rigorous mitigation

  3. Losses of Ammonia and Nitrate from Agriculture and Their Effect on Nitrogen Recovery in the European Union and the United States between 1900 and 2050.

    PubMed

    van Grinsven, Hans J M; Bouwman, Lex; Cassman, Kenneth G; van Es, Harold M; McCrackin, Michelle L; Beusen, Arthur H W

    2015-03-01

    Historical trends and levels of nitrogen (N) budgets and emissions to air and water in the European Union and the United States are markedly different. Agro-environmental policy approaches also differ, with emphasis on voluntary or incentive-based schemes in the United States versus a more regulatory approach in the European Union. This paper explores the implications of these differences for attaining long-term policy targets for air and water quality. Nutrient surplus problems were more severe in the European Union than in the United States during the 1970s and 1980s. The EU Nitrates and National Emission Ceilings directives contributed to decreases in fertilizer use, N surplus, and ammonia (NH) emissions, whereas in the United States they stabilized, although NH emissions are still increasing. These differences were analyzed using statistical data for 1900-2005 and the global IMAGE model. IMAGE could reproduce NH emissions and soil N surpluses at different scales (European Union and United States, country and state) and N loads in the Rhine and Mississippi. The regulation-driven changes during the past 25 yr in the European Union have reduced public concerns and have brought agricultural N loads to the aquatic environment closer to US levels. Despite differences in agro-environmental policies and agricultural structure (more N-fixing soybean and more spatially separated feed and livestock production in the United States than in the European Union), current N use efficiency in US and EU crop production is similar. IMAGE projections for the IAASTD-baseline scenario indicate that N loading to the environment in 2050 will be similar to current levels. In the United States, environmental N loads will remain substantially smaller than in the European Union, whereas agricultural production in 2050 in the United States will increase by 30% relative to 2005, as compared with an increase of 8% in the European Union. However, in the United States, even rigorous mitigation

  4. Hydrologic conditions and water quality in an agricultural area in Kleberg and Nueces Counties, Texas, 1996-98

    USGS Publications Warehouse

    Ockerman, Darwin J.; Petri, Brian L.

    2001-01-01

    During 1996?98, rainfall and runoff were monitored on a 49,680-acre agricultural watershed in Kleberg and Nueces Counties in South Texas. Nineteen rainfall samples were analyzed for selected nutrients, and runoff samples from 29 storms were analyzed for major ions, nutrients, and pesticides. Loads of nutrients in rainfall and loads of nutrients and pesticides in runoff were computed. For a 40,540-acre part of the watershed (lower study area), constituent loads entering the watershed in rainfall, in runoff from the upper study area, and from agricultural chemical applications to the lower study area were compared with runoff loads exiting the lower study area. Total rainfall for 1996?98 averaged 25.86 inches per year, which is less than the long-term annual average rainfall of 29.80 inches for the area. Rainfall and runoff during 1996?98 were typical of historical patterns, with periods of below average rainfall and runoff interspersed with extreme events. Five individual storms accounted for about 38 percent of the total rainfall and 94 percent of the total runoff. During the 3-year study, the total nitrogen runoff yield from the lower study area was 1.3 pounds per acre per year, compared with 49 pounds per acre per year applied as fertilizer and 3.1 pounds per acre per year from rainfall. While almost all of the fertilizer and rainfall nitrogen was ammonia and nitrate, most of the nitrogen in runoff was particulate organic nitrogen, associated with crop residue. Total nitrogen exiting the lower study area in surface-water runoff was about 2.5 percent of the nitrogen inputs (fertilizer and rainfall nitrogen). Annual deposition of total nitrogen entering the lower study area in rainfall exceeded net yields of total nitrogen exiting the watershed in runoff because most of the rainfall does not contribute to runoff. During the study, the total phosphorus runoff yield from the lower study area was 0.48 pound per acre per year compared with 4.2 pounds per acre per year

  5. [Nitrates and nitrites content in the samples taken from the dug and drilled wells from the area of Podkarpacie region as a methemoglobinemia risk factors].

    PubMed

    Bilek, Maciej; Rybakowa, Maria

    2014-01-01

    The aim of the study was to determine the nitrates and nitrites content in water samples taken from fourteen dug and drilled wells from the area of Podkarpacie, as well as a summary of the previously performed analysis. Private water intakes are not under the supervision of the State Sanitary Inspection. So in the case of exceeding the standards provided by the Regulation of the Minister of Health, regulating the requirements for drinking water, private water intakes can be a serious threat to the health of consumers. Particularly at risk are infants, in whom nitrates and especially nitrites can cause, among others, methemoglobinemia. The analysis was performed by ion chromatography method, making it possible to simultaneously determining the concentrations of nitrates and nitrites. As it turned out there was no presence of nitrites in the water of the tested wells. In five samples taken from the dug wells nitrates concentration exceeding the norm of 50 mg/L have been reported. In two cases, exceeding the nitrate concentrations were significant: 96.53 mg L and 204.65 mg/L.

  6. Areas of Increasing Agricultural Abandonment Overlap the Distribution of Previously Common, Currently Threatened Plant Species

    PubMed Central

    Osawa, Takeshi; Kohyama, Kazunori; Mitsuhashi, Hiromune

    2013-01-01

    Human-driven land-use changes increasingly threaten biodiversity. In agricultural ecosystems, abandonment of former farmlands constitutes a major land-use shift. We examined the relationships between areas in which agriculture has been abandoned and the distribution records of threatened plant species across Japan. We selected 23 plant species that are currently identified as threatened but were previously common in the country as indicators of threatened plant species. The areas of abandoned farmlands within the distribution ranges of the indicator species were significantly larger than the proportion of abandoned farmland area across the whole country. Also, abandoned farmland areas were positively correlated with the occurrence of indicator species. Therefore, sections of agricultural landscape that are increasingly becoming abandoned and the distribution ranges of indicator species overlapped. These results suggest that abandoned farmland areas contain degraded or preferred habitats of threatened plant species. We propose that areas experiencing increased abandonment of farmland can be divided into at least two categories: those that threaten the existence of threatened species and those that provide habitats for these threatened species. PMID:24260328

  7. Atrazine concentrations, gonadal gross morphology and histology in ranid frogs collected in Michigan agricultural areas.

    PubMed

    Murphy, M B; Hecker, M; Coady, K K; Tompsett, A R; Jones, P D; Du Preez, L H; Everson, G J; Solomon, K R; Carr, J A; Smith, E E; Kendall, R J; Van Der Kraak, G; Giesy, J P

    2006-03-10

    The triazine herbicide atrazine has been suggested to be a potential disruptor of normal sexual development in male frogs. The goals of this study were to collect native ranid frogs from sites in agricultural and non-agricultural areas and determine whether hypothesised atrazine effects on the gonads could be observed at the gross morphological and histological levels. Juvenile and adult green frogs (Rana clamitans), bullfrogs (R. catesbeiana) and leopard frogs (R. pipiens) were collected in the summers of 2002 and 2003. Atrazine concentrations were below the limit of quantification at non-agricultural sites, and concentrations did not exceed 2 microg/L at most agricultural sites. One concentration greater than 200 microg atrazine/L was measured once at one site in 2002. Hermaphroditic individuals with both male and female gonad tissue in either one or both gonads, were found at a low incidence at both non-agricultural and agricultural sites, and in both adults and juveniles. Testicular oocytes (TO) were found in male frogs at most of the sites, with the greatest incidence occurring in juvenile leopard frogs. TO incidence was not significantly different between agricultural and non-agricultural sites with the exception of juveniles collected in 2003. Atrazine concentrations were not significantly correlated with the incidence of hermaphroditism, but maximum atrazine concentrations were correlated with TO incidence in juvenile frogs in 2003. However, given the lack of a consistent relationship between atrazine concentrations and TO incidence, it is more likely the TOs observed in this study result from natural processes in development rather than atrazine exposure.

  8. Modeling groundwater nitrate concentrations in private wells in Iowa.

    PubMed

    Wheeler, David C; Nolan, Bernard T; Flory, Abigail R; DellaValle, Curt T; Ward, Mary H

    2015-12-01

    Contamination of drinking water by nitrate is a growing problem in many agricultural areas of the country. Ingested nitrate can lead to the endogenous formation of N-nitroso compounds, potent carcinogens. We developed a predictive model for nitrate concentrations in private wells in Iowa. Using 34,084 measurements of nitrate in private wells, we trained and tested random forest models to predict log nitrate levels by systematically assessing the predictive performance of 179 variables in 36 thematic groups (well depth, distance to sinkholes, location, land use, soil characteristics, nitrogen inputs, meteorology, and other factors). The final model contained 66 variables in 17 groups. Some of the most important variables were well depth, slope length within 1 km of the well, year of sample, and distance to nearest animal feeding operation. The correlation between observed and estimated nitrate concentrations was excellent in the training set (r-square=0.77) and was acceptable in the testing set (r-square=0.38). The random forest model had substantially better predictive performance than a traditional linear regression model or a regression tree. Our model will be used to investigate the association between nitrate levels in drinking water and cancer risk in the Iowa participants of the Agricultural Health Study cohort.

  9. Modeling groundwater nitrate concentrations in private wells in Iowa.

    PubMed

    Wheeler, David C; Nolan, Bernard T; Flory, Abigail R; DellaValle, Curt T; Ward, Mary H

    2015-12-01

    Contamination of drinking water by nitrate is a growing problem in many agricultural areas of the country. Ingested nitrate can lead to the endogenous formation of N-nitroso compounds, potent carcinogens. We developed a predictive model for nitrate concentrations in private wells in Iowa. Using 34,084 measurements of nitrate in private wells, we trained and tested random forest models to predict log nitrate levels by systematically assessing the predictive performance of 179 variables in 36 thematic groups (well depth, distance to sinkholes, location, land use, soil characteristics, nitrogen inputs, meteorology, and other factors). The final model contained 66 variables in 17 groups. Some of the most important variables were well depth, slope length within 1 km of the well, year of sample, and distance to nearest animal feeding operation. The correlation between observed and estimated nitrate concentrations was excellent in the training set (r-square=0.77) and was acceptable in the testing set (r-square=0.38). The random forest model had substantially better predictive performance than a traditional linear regression model or a regression tree. Our model will be used to investigate the association between nitrate levels in drinking water and cancer risk in the Iowa participants of the Agricultural Health Study cohort. PMID:26232757

  10. Modeling groundwater nitrate concentrations in private wells in Iowa

    USGS Publications Warehouse

    Wheeler, David C.; Nolan, Bernard T.; Flory, Abigail R.; DellaValle, Curt T.; Ward, Mary H.

    2015-01-01

    Contamination of drinking water by nitrate is a growing problem in many agricultural areas of the country. Ingested nitrate can lead to the endogenous formation of N-nitroso compounds, potent carcinogens. We developed a predictive model for nitrate concentrations in private wells in Iowa. Using 34,084 measurements of nitrate in private wells, we trained and tested random forest models to predict log nitrate levels by systematically assessing the predictive performance of 179 variables in 36 thematic groups (well depth, distance to sinkholes, location, land use, soil characteristics, nitrogen inputs, meteorology, and other factors). The final model contained 66 variables in 17 groups. Some of the most important variables were well depth, slope length within 1 km of the well, year of sample, and distance to nearest animal feeding operation. The correlation between observed and estimated nitrate concentrations was excellent in the training set (r-square = 0.77) and was acceptable in the testing set (r-square = 0.38). The random forest model had substantially better predictive performance than a traditional linear regression model or a regression tree. Our model will be used to investigate the association between nitrate levels in drinking water and cancer risk in the Iowa participants of the Agricultural Health Study cohort.

  11. 7 CFR 3402.4 - Food and agricultural sciences areas targeted for National Needs Graduate and Postdoctoral...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... National Needs Graduate and Postdoctoral Fellowship Grants Program support. 3402.4 Section 3402.4... AGRICULTURE FOOD AND AGRICULTURAL SCIENCES NATIONAL NEEDS GRADUATE AND POSTGRADUATE FELLOWSHIP GRANTS PROGRAM... Postdoctoral Fellowship Grants Program support. Areas of the food and agricultural sciences,...

  12. 7 CFR 3402.4 - Food and agricultural sciences areas targeted for National Needs Graduate and Postdoctoral...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... National Needs Graduate and Postdoctoral Fellowship Grants Program support. 3402.4 Section 3402.4... AGRICULTURE FOOD AND AGRICULTURAL SCIENCES NATIONAL NEEDS GRADUATE AND POSTGRADUATE FELLOWSHIP GRANTS PROGRAM... Postdoctoral Fellowship Grants Program support. Areas of the food and agricultural sciences,...

  13. 7 CFR 3402.4 - Food and agricultural sciences areas targeted for National Needs Graduate and Postdoctoral...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... National Needs Graduate and Postdoctoral Fellowship Grants Program support. 3402.4 Section 3402.4... AGRICULTURE FOOD AND AGRICULTURAL SCIENCES NATIONAL NEEDS GRADUATE AND POSTGRADUATE FELLOWSHIP GRANTS PROGRAM... Postdoctoral Fellowship Grants Program support. Areas of the food and agricultural sciences,...

  14. 7 CFR 3402.4 - Food and agricultural sciences areas targeted for National Needs Graduate and Postdoctoral...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... National Needs Graduate and Postdoctoral Fellowship Grants Program support. 3402.4 Section 3402.4... AGRICULTURE FOOD AND AGRICULTURAL SCIENCES NATIONAL NEEDS GRADUATE AND POSTGRADUATE FELLOWSHIP GRANTS PROGRAM... Postdoctoral Fellowship Grants Program support. Areas of the food and agricultural sciences,...

  15. Estimation Of Cultivated Area In Small Plot Agriculture In Africa For Food Security Purposes

    NASA Astrophysics Data System (ADS)

    Holecz, Francesco; Collivignarelli, Francesco; Barbieri, Massimo

    2013-12-01

    Cultivated area in small plot agriculture in Africa is estimated using a synergetic approach based on multi-sensor, multi-temporal Synthetic Aperture Radar (SAR) data. The method - which is based on the utilization of ALOS PALSAR-1, Cosmo-SkyMed, ENVISAT ASAR data involving different processing techniques - consists in the generation of three independent and complementary products, which in turn they are fused, enabling the generation of the cultivated area. Each intermediate product has a clear meaning within agriculture and food security: i) the potential crop extent prior to the crop season; ii) the potential area at start of the crop season; iii) the crop growth extent during the rainfed crop season. The proposed methodology has been implemented and demonstrated in Malawi. The obtained results show an overall accuracy exceeding 90%.

  16. Hydrogeochemistry of alluvial groundwaters in an agricultural area: an implication for groundwater contamination susceptibility.

    PubMed

    Chae, Gi-Tak; Kim, Kangjoo; Yun, Seong-Taek; Kim, Kyoung-Ho; Kim, Soon-Oh; Choi, Byoung-Young; Kim, Hyoung-Soo; Rhee, Chul Woo

    2004-04-01

    Alluvial groundwaters in the area where intensive agricultural activity takes place were geochemically investigated to evaluate factors regulating groundwater quality of alluvial aquifers. For this study, 55 groundwater samples were taken from the uniformly distributed irrigation wells and were classified into three distinct groups according to their geochemical characteristics. This study reveals that the groundwater quality and the geochemical characteristics of the clustered groups are consistent with the geology of the area. The samples collected from the area where a thick silt bed overlies the sand aquifer are clustered into Group II and show water quality that is only slightly affected by the contaminants originating from the land surface. However, groundwaters of this group are very high in Fe and Mn levels due to strong anoxic condition caused by the thick silt bed. In contrast, Group I shows water quality largely influenced by agricultural activities (i.e., fertilization, liming) and occurs in the area adjacent to the river where the silt bed is not observed and the sand aquifer is covered with sandy soils. Group III mostly occurs in the upgradient of Group I where a thin, silty soil covers the sand aquifer. In overall, the results show that the clustered groups closely reflect the groundwater susceptibility to the contaminants originated from the land surface. This suggests that groundwater clustering based on water chemistry could be applied to the contamination susceptibility assessment for groundwaters in the agricultural area.

  17. Trends in chloride, dissolved-solids, and nitrate concentrations in ground water, Carson Valley and Topaz Lake Areas, Douglas County, Nevada, 1959-88

    USGS Publications Warehouse

    Thodal, C.E.

    1996-01-01

    Rapid population growth in Douglas County, an area of approximately 750 square miles in west-central Nevada, has led to concern about the present and future effects of development on ground water. This report describes the results of two nonparametric statistical procedures applied to detect trends in concentrations of chloride, dissolved solids, and nitrate in ground water. The water-quality data consist of analytical results from ground-water samples collected and analyzed by the U. S. Geological Survey and ground-water-quality data provided by the Nevada Bureau of Health Protection Services for the Carson Valley and Topaz Lake areas of Douglas County, Nevada. For purposes of this study, statistical significance, expressed as the p-value, was set at 0.1. The Mann-Whitney-Wilcoxan rank-sum test detected increasing step-trends for nitrate in one of seven residential areas and for dissolved-solids concentrations throughout the study area. Decreasing step-trends for chloride and dissolved-solids concentrations were detected in the west Carson Valley area. Kendall's Tau detected monotonic trends for increasing nitrate concentrations at four domestic wells and for increasing dissolved-solids concentrations at two domestic wells. No other statistically significant trends were indicated by either test. Land-use relations to areas where increasing trends were detected suggest that the density of individual wastewater-treatment systems may exceed the capacity of soils to treat wastewater leachate.

  18. Assessment of Meteorological and Agriculture Drought Severity in Barani Areas of Pakistan

    NASA Astrophysics Data System (ADS)

    Haque, Saad Ul

    2016-07-01

    Drought is a natural hazard and part of climatic condition for all regions of the world. It is the condition of moisture deficit caused by a certain climatic conditions occurring at a specific location for a specific duration. Stems from the lack of precipitation, precipitation deficiency for a season, a year or longer and is triggered, when water supplies become insufficient to meet the requirements. Pakistan predominantly consists of arid and semiarid regions with a diversified climate where Agriculture sector plays a vital role in countries economy, as it is the largest sector of Pakistan, accounting for over 20.9 percent of GDP. Nearly 62 percent of the country's rural population and is directly or indirectly linked with agriculture for their livelihood. (Pakistan Economic Survey, 2011). Thus, for such type of landscapes where agriculture mainly depends on the amount of precipitation and there is no use of canal irrigation system, so there is a need to make some immediate interventions in the area of drought hazard management & a proactive planning to mitigate its adverse impacts. In this study drought is assessed on its sequential stages, first of all meteorological conditions that include rainfall data and MODIS Satellite NDVI product, having good temporal resolution for drought assessment in order to identify dry spell period. This whole waterless season leads to agricultural drought as crops and vegetation begin to degrade with low production rate. Some more parameters such as Max. Temperature, Humidity, Solar Radiation, Evapotranspiration were incorporated by assigning suitable weights according to their sensitivity for drought. Severity of Agricultural drought was determine by using NDVI anomaly and crop anomaly pattern. Finally, the correlation regression analysis was performed to identify the effect of different dependent variables on their supporting parameters. The combined drought severity map was generated by overlying the agricultural and

  19. Nitrate in groundwater of the United States, 1991-2003.

    PubMed

    Burow, Karen R; Nolan, Bernard T; Rupert, Michael G; Dubrovsky, Neil M

    2010-07-01

    An assessment of nitrate concentrations in groundwater in the United States indicates that concentrations are highest in shallow, oxic groundwater beneath areas with high N inputs. During 1991-2003, 5101 wells were sampled in 51 study areas throughout the U.S. as part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) program. The well networks reflect the existing used resource represented by domestic wells in major aquifers (major aquifer studies), and recently recharged groundwater beneath dominant land-surface activities (land-use studies). Nitrate concentrations were highest in shallow groundwater beneath agricultural land use in areas with well-drained soils and oxic geochemical conditions. Nitrate concentrations were lowest in deep groundwater where groundwater is reduced, or where groundwater is older and hence concentrations reflect historically low N application rates. Classification and regression tree analysis was used to identify the relative importance of N inputs, biogeochemical processes, and physical aquifer properties in explaining nitrate concentrations in groundwater. Factors ranked by reduction in sum of squares indicate that dissolved iron concentrations explained most of the variation in groundwater nitrate concentration, followed by manganese, calcium, farm N fertilizer inputs, percent well-drained soils, and dissolved oxygen. Overall, nitrate concentrations in groundwater are most significantly affected by redox conditions, followed by nonpoint-source N inputs. Other water-quality indicators and physical variables had a secondary influence on nitrate concentrations.

  20. Nitrate in groundwater of the United States, 1991-2003

    USGS Publications Warehouse

    Burow, Karen R.; Nolan, Bernard T.; Rupert, Michael G.; Dubrovsky, Neil M.

    2010-01-01

    An assessment of nitrate concentrations in groundwater in the United States indicates that concentrations are highest in shallow, oxic groundwater beneath areas with high N inputs. During 1991-2003, 5101 wells were sampled in 51 study areas throughout the U.S. as part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) program. The well networks reflect the existing used resource represented by domestic wells in major aquifers (major aquifer studies), and recently recharged groundwater beneath dominant land-surface activities (land-use studies). Nitrate concentrations were highest in shallow groundwater beneath agricultural land use in areas with well-drained soils and oxic geochemical conditions. Nitrate concentrations were lowest in deep groundwater where groundwater is reduced, or where groundwater is older and hence concentrations reflect historically low N application rates. Classification and regression tree analysis was used to identify the relative importance of N inputs, biogeochemical processes, and physical aquifer properties in explaining nitrate concentrations in groundwater. Factors ranked by reduction in sum of squares indicate that dissolved iron concentrations explained most of the variation in groundwater nitrate concentration, followed by manganese, calcium, farm N fertilizer inputs, percent well-drained soils, and dissolved oxygen. Overall, nitrate concentrations in groundwater are most significantly affected by redox conditions, followed by nonpoint-source N inputs. Other water-quality indicators and physical variables had a secondary influence on nitrate concentrations.

  1. Study of hybrid power system potential to power agricultural water pump in mountain area

    NASA Astrophysics Data System (ADS)

    Syuhada, Ahmad; Mubarak, Amir Zaki; Maulana, M. Ilham

    2016-03-01

    As industry and Indonesian economy grow fast, there are a lot of agricultural land has changed into housing and industrial land. This causes the agricultural land moves to mountain area. In mountainous agricultural area, farmers use the water resources of small rivers in the groove of the mountain to irrigate the farmland. Farmers use their power to lift up water from the river to their land which causes inefectivity in the work of the farmers. Farmers who have capital utilize pump to raise water to their land. The only way to use pump in mountain area is by using fuel energy as there is no electricity, and the fuel price in mountain area is very expensive. Based on those reasons it is wise to consider the exploration of renewable energy available in the area such as solar energy, wind energy and hybrid energy. This study analyses the potential of the application of hybrid power plant, which is the combination of solar and wind energy, to power agricultural pump. In this research, the data of wind speed and solar radiation are collected from the measurement of BMKG SMPK Plus Sare. Related to the solar energy, the photovoltaic output power calculation is 193 W with duration of irradiation of 5 hours/day. While for the wind energy, the output power of the wind turbine is 459.84 W with blade diameter of 3 m and blow duration of 7 hours/day. The power of the pump is 558 W with 8 hours of usage, and the water capacity is 2.520 liters/hour for farmland with the area of 15 ha. Based on the analysis result, the designed system will generate electricity of 3.210 kW/year with initial investment of US 14,938.

  2. Examining soil erosion and nutrient accumulation in forested and agriculture lands of the low mountainous area of Northern Vietnam

    NASA Astrophysics Data System (ADS)

    Pham, A. T.; Gomi, T.; Takahisa, F.; Phung, K. V.

    2011-12-01

    We examined soil erosion and nutrient accumulations in the Xuanmai area located in the low mountainous region of Northern Vietnam, based on field investigations and remote sensing approaches. The study area had been degraded by land-use change from forest to agriculture in the last 20 years. In contrast, around the study area, the Vietnam government promoted reforestation projects. Such changes in land-use conditions, which may or may not be associated with vegetation ground cover conditions, potentially alter soil erosion and nutrient accumulation. We selected 10 dominant land-use types including forested land (e.g., Pinus massoniana and Acacia mangium plantation) agriculture land (e.g., Cassava), and bare land. We established three 1 x 1 m plots in each land-use type in September 2010. Vegetation biomass, litter cover, soil erosion (height of soil pedestal), and soil physical (soil bulk density and particle size distribution) and chemical properties (Total soil carbon, nitrate, and phosphorus) were measured. Height of soil pedestal can be a record of soil erosion by rain splash during rainy periods from April to August (prior to our field study). We also conducted remote sensing analysis using Landsat TM images obtained in 1993, 2000, and 2007 for identifying temporal patterns of land-use types. We found that the intensity of soil erosion depended primary on current vegetation ground cover condition with no regard of land-use. Hence, nutrient accumulation varied among vegetation ground cover and soil erosion. Remote sensing analysis suggested that shrub and bare lands had been altered from forested land more recently. Our finding suggested that variability of soil nutrient conditions can be associated with long-term soil erosion and production processes. Findings of our study are that: (1) current vegetation and litter ground cover affected the amount of surface soil erosion, and (2) legacy of land-use can be more critical for soil nutrient accumulation. Both

  3. Real-time continuous nitrate monitoring in Illinois in 2013

    USGS Publications Warehouse

    Warner, Kelly L.; Terrio, Paul J.; Straub, Timothy D.; Roseboom, Donald; Johnson, Gary P.

    2013-01-01

    Many sources contribute to the nitrogen found in surface water in Illinois. Illinois is located in the most productive agricultural area in the country, and nitrogen fertilizer is commonly used to maximize corn production in this area. Additionally, septic/wastewater systems, industrial emissions, and lawn fertilizer are common sources of nitrogen in urban areas of Illinois. In agricultural areas, the use of fertilizer has increased grain production to meet the needs of a growing population, but also has resulted in increases in nitrogen concentrations in many streams and aquifers (Dubrovsky and others, 2010). The urban sources can increase nitrogen concentrations, too. The Federal limit for nitrate nitrogen in water that is safe to drink is 10 milligrams per liter (mg/L) (http://water.epa.gov/drink/contaminants/basicinformation/nitrate.cfm, accessed on May 24, 2013). In addition to the concern with nitrate nitrogen in drinking water, nitrogen, along with phosphorus, is an aquatic concern because it feeds the intensive growth of algae that are responsible for the hypoxic zone in the Gulf of Mexico. The largest nitrogen flux to the waters feeding the Gulf of Mexico is from Illinois (Alexander and others, 2008). Most studies of nitrogen in surface water and groundwater include samples for nitrate nitrogen collected weekly or monthly, but nitrate concentrations can change rapidly and these discrete samples may not capture rapid changes in nitrate concentrations that can affect human and aquatic health. Continuous monitoring for nitrate could inform scientists and water-resource managers of these changes and provide information on the transport of nitrate in surface water and groundwater.

  4. Nitrate reduction

    DOEpatents

    Dziewinski, Jacek J.; Marczak, Stanislaw

    2000-01-01

    Nitrates are reduced to nitrogen gas by contacting the nitrates with a metal to reduce the nitrates to nitrites which are then contacted with an amide to produce nitrogen and carbon dioxide or acid anions which can be released to the atmosphere. Minor amounts of metal catalysts can be useful in the reduction of the nitrates to nitrites. Metal salts which are formed can be treated electrochemically to recover the metals.

  5. The Management Options of Water for the Development of Agriculture in Dry Areas

    NASA Astrophysics Data System (ADS)

    Irshad, M.; Inoue, M.; Ashraf, M.; Al-Busaidi, A.

    The natural resource base of land, water and vegetation in arid and semi arid areas is highly fragile and greatly vulnerable to degradation especially in the developing countries. The demand for water is constantly increasing as a result of population growth and the expansion of agriculture and industry. Fresh water resources are limited in the arid and semi-arid areas whereas the existing water resources are often overused and misused. The lack of water management in the arid areas generated numerous economic, social and ecological issues. Agriculture currently accounts for nearly 70-80% of water consumption in the developing countries. The productivity of water use in agriculture needs to enhance in order both to avoid exacerbating the water crisis and to prevent considerable food shortages. More efficient use of existing water resources and adequate management of soils could prove to be the effective tool for improving arid lands. The technologies, skills and capital resources required to overcome the poor and extreme distribution of water resources through storage and transfer are not available and widely used. As a consequence there is critically low access to water for agriculture, drinking and sanitation and the environment. Poor access to water is among the leading factors hindering sustainable development in semi-arid and arid regions. Conventional irrigation management should be revised to ensure maximum water productivity instead of land productivity for dry farming systems. Under conditions of increasing water scarcity, the key to sustaining rural livelihoods is improving the productivity and reliability of rainfed agriculture by using limited rainfall more productively, through optimal on-farm soil, water and crop management practices that conserve soil moisture and increase water use efficiency. Conserving and augmenting water supplies through rainwater harvesting and precision irrigation provide new opportunity for productive dry land farming

  6. Nitrate and periplasmic nitrate reductases

    PubMed Central

    Sparacino-Watkins, Courtney; Stolz, John F.; Basu, Partha

    2014-01-01

    The nitrate anion is a simple, abundant and relatively stable species, yet plays a significant role in global cycling of nitrogen, global climate change, and human health. Although it has been known for quite some time that nitrate is an important species environmentally, recent studies have identified potential medical applications. In this respect the nitrate anion remains an enigmatic species that promises to offer exciting science in years to come. Many bacteria readily reduce nitrate to nitrite via nitrate reductases. Classified into three distinct types – periplasmic nitrate reductase (Nap), respiratory nitrate reductase (Nar) and assimilatory nitrate reductase (Nas), they are defined by their cellular location, operon organization and active site structure. Of these, Nap proteins are the focus of this review. Despite similarities in the catalytic and spectroscopic properties Nap from different Proteobacteria are phylogenetically distinct. This review has two major sections: in the first section, nitrate in the nitrogen cycle and human health, taxonomy of nitrate reductases, assimilatory and dissimilatory nitrate reduction, cellular locations of nitrate reductases, structural and redox chemistry are discussed. The second section focuses on the features of periplasmic nitrate reductase where the catalytic subunit of the Nap and its kinetic properties, auxiliary Nap proteins, operon structure and phylogenetic relationships are discussed. PMID:24141308

  7. A Hybrid Surface Energy Balance Approach for Large Scale Evapotranspiration Estimation and Prediction in Agricultural Areas

    NASA Astrophysics Data System (ADS)

    Neale, C. M.; Vinukollu, R. K.; Chavez, J. L.

    2005-05-01

    Over the last few years, several surface energy balance methods for the estimation of latent heat fluxes from remotely sensed satellite imagery have been introduced and/or refined. These models have shown the ability of obtaining seasonal spatially distributed evapotranspiration fluxes at various scales and over large areas. In the arid western United States, water managers are challenged in balancing the high consumptive use of irrigated agriculture with competing urban and ecological uses of fresh water. Water managers from Irrigation Districts and Federal Agencies such as the US Bureau of Reclamation have a need for improved operational tools for the prediction of evapotranspiration and irrigation water demand on a five to ten day timeframe. The paper will present a hybrid model that couples the surface energy balance approach with a simple empirical reflectance-based crop coefficient model, for estimation and prediction of evapotranspiration over large agricultural areas. The model is applied to a rain-fed intensively cultivated agricultural area, close to Ames, Iowa during the summer of 2002. The satellite, airborne and ground fluxes were collected during the SMACEX 02 experiment. The model is run in both simulation and prediction mode and the derived latent heat fluxes are compared spatially and temporally to aircraft derived fluxes from the USU airborne system and ground measured fluxes at thirteen eddy covariance stations, using appropriate upwind footprint source area functions.

  8. Ecohydrological modeling: the consideration of agricultural trees is essential in the Mediterranean area

    NASA Astrophysics Data System (ADS)

    Fader, Marianela; von Bloh, Werner; Shi, Sinan; Bondeau, Alberte; Cramer, Wolfgang

    2016-04-01

    In the Mediterranean region, climate and land use change are expected to impact on natural and agricultural ecosystems by warming, reduced rainfall and direct degradation of ecosystems. Human population growth and socioeconomic changes, notably on the Eastern and Southern shores, will require increases in food production and put additional pressure on agro-ecosystems and water resources. Coping with these challenges requires informed decisions that, in turn, require assessments by means of a comprehensive ecohydrological model. Here we present here the inclusion of 10 Mediterranean agricultural plants, mainly perennial crops, in an agro-ecosystem model (LPJmL, "Lund-Potsdam-Jena managed Land"): nut trees, date palms, citrus trees, orchards, olive trees, grapes, cotton, potatoes, vegetables and fodder grasses. The model was then successfully tested in three model outputs: agricultural yields, irrigation requirements and soil carbon density. A first application of the model indicates that, currently, agricultural trees consume in average more irrigation water per hectare than annual crops. Also, different crops show different magnitude of changes in net irrigation requirements due to climate change, being the increases most pronounced in agricultural trees. This is very relevant since the Mediterranean area as a whole might face an increase in gross irrigation requirements between 4% and 74% from climate change and population growth if irrigation systems and conveyance are not improved. Additionally, future water scarcity might pose further challenges to the agricultural sector: Algeria, Libya, Israel, Jordan, Lebanon, Syria, Serbia, Morocco, Tunisia and Spain have a high risk of not being able to sustainably meet future irrigation water requirements in some scenarios by the end of the century (1). The importance of including agricultural trees in the ecohydrological models is also shown in the results concerning soil organic carbon (SOC). Since in former model

  9. The Importance of Landscape Elements for Bat Activity and Species Richness in Agricultural Areas

    PubMed Central

    Heim, Olga; Treitler, Julia T.; Tschapka, Marco; Knörnschild, Mirjam; Jung, Kirsten

    2015-01-01

    Landscape heterogeneity is regarded as a key factor for maintaining biodiversity and ecosystem function in production landscapes. We investigated whether grassland sites at close vicinity to forested areas are more frequently used by bats. Considering that bats are important consumers of herbivorous insects, including agricultural pest, this is important for sustainable land management. Bat activity and species richness were assessed using repeated monitoring from May to September in 2010 with acoustic monitoring surveys on 50 grassland sites in the Biosphere Reserve Schorfheide-Chorin (North-East Germany). Using spatial analysis (GIS), we measured the closest distance of each grassland site to potentially connecting landscape elements (e.g., trees, linear vegetation, groves, running and standing water). In addition, we assessed the distance to and the percent land cover of forest remnants and urban areas in a 200 m buffer around the recording sites to address differences in the local landscape setting. Species richness and bat activity increased significantly with higher forest land cover in the 200 m buffer and at smaller distance to forested areas. Moreover, species richness increased in proximity to tree groves. Larger amount of forest land cover and smaller distance to forest also resulted in a higher activity of bats on grassland sites in the beginning of the year during May, June and July. Landscape elements near grassland sites also influenced species composition of bats and species richness of functional groups (open, edge and narrow space foragers). Our results highlight the importance of forested areas, and suggest that agricultural grasslands that are closer to forest remnants might be better buffered against outbreaks of agricultural pest insects due to higher species richness and higher bat activity. Furthermore, our data reveals that even for highly mobile species such as bats, a very dense network of connecting elements within the landscape is

  10. The Importance of Landscape Elements for Bat Activity and Species Richness in Agricultural Areas.

    PubMed

    Heim, Olga; Treitler, Julia T; Tschapka, Marco; Knörnschild, Mirjam; Jung, Kirsten

    2015-01-01

    Landscape heterogeneity is regarded as a key factor for maintaining biodiversity and ecosystem function in production landscapes. We investigated whether grassland sites at close vicinity to forested areas are more frequently used by bats. Considering that bats are important consumers of herbivorous insects, including agricultural pest, this is important for sustainable land management. Bat activity and species richness were assessed using repeated monitoring from May to September in 2010 with acoustic monitoring surveys on 50 grassland sites in the Biosphere Reserve Schorfheide-Chorin (North-East Germany). Using spatial analysis (GIS), we measured the closest distance of each grassland site to potentially connecting landscape elements (e.g., trees, linear vegetation, groves, running and standing water). In addition, we assessed the distance to and the percent land cover of forest remnants and urban areas in a 200 m buffer around the recording sites to address differences in the local landscape setting. Species richness and bat activity increased significantly with higher forest land cover in the 200 m buffer and at smaller distance to forested areas. Moreover, species richness increased in proximity to tree groves. Larger amount of forest land cover and smaller distance to forest also resulted in a higher activity of bats on grassland sites in the beginning of the year during May, June and July. Landscape elements near grassland sites also influenced species composition of bats and species richness of functional groups (open, edge and narrow space foragers). Our results highlight the importance of forested areas, and suggest that agricultural grasslands that are closer to forest remnants might be better buffered against outbreaks of agricultural pest insects due to higher species richness and higher bat activity. Furthermore, our data reveals that even for highly mobile species such as bats, a very dense network of connecting elements within the landscape is

  11. The Importance of Landscape Elements for Bat Activity and Species Richness in Agricultural Areas.

    PubMed

    Heim, Olga; Treitler, Julia T; Tschapka, Marco; Knörnschild, Mirjam; Jung, Kirsten

    2015-01-01

    Landscape heterogeneity is regarded as a key factor for maintaining biodiversity and ecosystem function in production landscapes. We investigated whether grassland sites at close vicinity to forested areas are more frequently used by bats. Considering that bats are important consumers of herbivorous insects, including agricultural pest, this is important for sustainable land management. Bat activity and species richness were assessed using repeated monitoring from May to September in 2010 with acoustic monitoring surveys on 50 grassland sites in the Biosphere Reserve Schorfheide-Chorin (North-East Germany). Using spatial analysis (GIS), we measured the closest distance of each grassland site to potentially connecting landscape elements (e.g., trees, linear vegetation, groves, running and standing water). In addition, we assessed the distance to and the percent land cover of forest remnants and urban areas in a 200 m buffer around the recording sites to address differences in the local landscape setting. Species richness and bat activity increased significantly with higher forest land cover in the 200 m buffer and at smaller distance to forested areas. Moreover, species richness increased in proximity to tree groves. Larger amount of forest land cover and smaller distance to forest also resulted in a higher activity of bats on grassland sites in the beginning of the year during May, June and July. Landscape elements near grassland sites also influenced species composition of bats and species richness of functional groups (open, edge and narrow space foragers). Our results highlight the importance of forested areas, and suggest that agricultural grasslands that are closer to forest remnants might be better buffered against outbreaks of agricultural pest insects due to higher species richness and higher bat activity. Furthermore, our data reveals that even for highly mobile species such as bats, a very dense network of connecting elements within the landscape is

  12. Satellite Estimates of Crop Area and Maize Yield in Zambia's Agricultural Districts

    NASA Astrophysics Data System (ADS)

    Azzari, G.; Lobell, D. B.

    2015-12-01

    Predicting crop yield and area from satellite is a valuable tool to monitor different aspects of productivity dynamics and food security. In Sub-Saharan Africa, where the agricultural landscape is complex and dominated by smallholder systems, such dynamics need to be investigated at the field scale. We leveraged the large data pool and computational power of Google Earth Engine to 1) generate 30 m resolution cover maps of selected provinces of Zambia, 2) estimate crop area, and 3) produce yearly maize yield maps using the recently developed SCYM (Scalable satellite-based Crop Yield Mapper) algorithm. We will present our results and their validation against a ground survey dataset collected yearly by the Zambia Ministry of Agriculture from about 12,500 households.

  13. Remotely Sensed Estimates of Evapotranspiration in Agricultural Areas of Northwestern Nevada: Drought, Reliance, and Water Transfers

    NASA Astrophysics Data System (ADS)

    Bromley, Matthew

    The arid landscape of northwestern Nevada is punctuated by agricultural communities that rely on water primarily supplied by the diversion of surface waters and secondarily by groundwater resources. Annual precipitation in the form of winter snowfall largely determines the amount of surface water that is available for irrigation for the following agricultural growing season. During years of insufficient surface water supplies, particular basins can use groundwater in order to meet irrigation needs. The amount of water used to irrigate agricultural land is influenced by land use changes, such as fallowing, and water right transfers from irrigation to municipal use. To evaluate agricultural water consumption with respect to variations in weather, water supply, and land use changes, monthly estimates of evapotranspiration (ET) were derived from Landsat multispectral optical and thermal imagery over a eleven-year period (2001 to 2011) and compared to variations in weather, water supply, and land use across four hydrographic areas in northwestern Nevada. Monthly ET was estimated using a land surface energy balance model, Mapping EvapoTranspiration at high Resolution with Internalized Calibration (METRIC), using Landsat 5 and Landsat 7 imagery combined with local atmospheric water demand estimates. Estimates of net ET were created by subtracting monthly precipitation from METRIC-derived ET, and seasonal estimates were generated by combining monthly ET for April-October (the regional agricultural growing season). Results highlight that a range of geographic, climatic, hydrographic, and anthropogenic factors influence ET. Hydrographic areas such as Mason Valley have the ability to mitigate deficiencies in surface water supplies by pumping supplemental groundwater, thereby resulting in low annual variability in ET. Conversely, the community of Lovelock has access to limited upstream surface water storage and is restricted by groundwater that is saline and unsuitable for

  14. Monitoring Indicators for Mediterranean Wetland and Agricultural Area Using ALOS Data

    NASA Astrophysics Data System (ADS)

    Alexandridis, T. K.; Topaloglou, C. A.; Pardalis, I.; Tsakoumis, G.; Vogiatzis, M.; Andrianopoulos, A.; Takavakoglou, V.; Vougioukas, S.; Bochtis, D.; Zalidis, G. C.; Silleos, N. G.

    2008-11-01

    Agricultural and other human activities are a pressure to several Mediterranean wetland ecosystems. Monitoring the pressures and the state of the ecosystem is an important input to management activities. The aim of this work was to select and implement indicators for monitoring the natural and agricultural environment of a Mediterranean wetland using Earth Observation (EO), and specifically the recently launched ALOS satellite images. Multiple levels of data were collected and integrated: remote sensing data (ALOS AVNIR-2 and PALSAR), unmanned aerial vehicle (UAV) images, and observations during field surveys. EO and GIS methods used during monitoring of the study area involved preprocessing of the satellite images, enhancement of information, information extraction, and derivation of indicators. Geographic overlay comparison with results derived from the area in 2003 using a Terra/ASTER image was used to identify the changes that occurred during the last years. The methodology was applied in the wetland and surrounding agricultural area of Ramsar Convention site "lakes Koronia-Volvi" (Greece). Resulting thematic maps revealed and quantified the intensity of pressures in the vicinity of the protected wetland, the state of the wetland ecosystem, as well as the seasonal and long term temporal trends.

  15. Ammonia emissions, transport, and deposition downwind of agricultural areas at local to regional scales

    NASA Astrophysics Data System (ADS)

    Zondlo, Mark; Pan, Da; Golston, Levi; Sun, Kang; Tao, Lei

    2016-04-01

    Ammonia (NH3) emissions from agricultural areas show extreme spatiotemporal variations, yet agricultural emissions dominate the global NH3 budget and ammoniated aerosols are a dominant component of unhealthy fine particulate matter. The emissions of NH3 and their deposition near and downwind of agricultural areas is complex. As part of a multi-year field intensive along the Colorado Front Range (including the NASA DISCOVER-AQ and NSF FRAPPE field experiments), we have examined temporal emissions of NH3 from feedlots, regional transport of ammonia and ammoniated aerosols from the plains to relatively pristine regions in Rocky Mountain National Park, and dry deposition and re-emission of grassland NH3 in the park. Eddy covariance measurements at feedlots and natural grasslands in the mountains were conducted with newly-developed open-path, eddy covariance laser-based sensors for NH3 (0.7 ng NH3/m2/s detection limit at 10 Hz). These measurements were coupled with other NH3/NHx measurements from mobile laboratories, aircraft, and satellite to examine the transport of NH3 from agricultural areas to cleaner regions downwind. At the farm level, eddy covariance NH3 fluxes showed a strong diurnal component correlated with temperature regardless of the season but with higher absolute emissions in summer than winter. While farm-to-farm variability (N=62 feedlots) was high, similar diurnal trends were observed at all sites regardless of individual farm type (dairy, beef, sheep, poultry, pig). Deposition at scales of several km showed relatively small deposition (10% loss) based upon NH3/CH4 tracer correlations, though the NH3 concentrations were so elevated (up to ppmv) that these losses should not be neglected when considering near-farm deposition. Ammonia was efficiently transported at least 150 km during upslope events to the Colorado Front Range (ele. 3000-4000 m) based upon aircraft, mobile laboratory, and model measurements. The gas phase lifetime of NH3 was estimated to

  16. Pesticides in storm runoff from agricultural and urban areas in the Tuolumne River basin in the vicinity of Modesto, California

    USGS Publications Warehouse

    Kratzer, Charles R.

    1998-01-01

    The occurrence, concentrations, and loads of dissolved pesticides in storm runoff were compared for two contrasting land uses in the Tuolumne River Basin, California, during two different winter storms: agricultural areas (February 1994) and the Modesto urban area (February 1995). Both storms followed the main application period of pesticides on dormant almond orchards. Eight samples of runoff from agricultural areas were collected from a Tuolumne River site, and 10 samples of runoff from urban areas were collected from five storm drains. All samples were analyzed for 46 pesticides. Six pesticides were detected in runoff from agricultural areas, and 15 pesticides were detected in runoff from urban areas. Chlorpyrifos, diazinon, dacthal (DCPA), metolachlor, and simazine were detected in almost every sample. Median concentrations were higher in the runoff from urban areas for all pesticides except napropamide and simazine. The greater occurrence and concentrations in storm drains is partly attributed to dilution of agricultural runoff by nonstorm base-flow in the Tuolumne River and by storm runoff from nonagricultural and nonurban land. In most cases, the occurrence and relative concentrations of pesticides found in storm runoff from agricultural and urban areas were related to reported pesticide application. Pesticide concentrations in runoff from agricultural areas were more variable during the storm hydrograph than were concentrations in runoff from urban areas. All peak pesticide concentrations in runoff from agricultural areas occurred during the rising limb of the storm hydrograph, whereas peak concentrations in the storm drains occurred at varying times during the storm hydrograph. Transport of pesticides from agricultural areas during the February 1994 storm exceeded transport from urban areas during the February 1995 storm for chlorpyrifos, diazinon, metolachlor, napropamide, and simazine. Transport of DCPA was about the same from agricultural and urban

  17. Geochemical Trends and Natural Attenuation of RDX, Nitrate, and Perchlorate in the Hazardous Test Area Fractured-Granite Aquifer, White Sands Missile Range, New Mexico, 1996-2006

    USGS Publications Warehouse

    Langman, Jeff B.; Robertson, Andrew J.; Bynum, Jamar; Gebhardt, Fredrick E.

    2008-01-01

    A fractured-granite aquifer at White Sands Missile Range is contaminated with the explosive compound RDX, nitrate, and perchlorate (oxidizer associated with rocket propellant) from the previous use of the Open Burn/Open Detonation site at the Hazardous Test Area. RDX, nitrate, and perchlorate ground-water concentrations were analyzed to examine source characteristics, spatial and temporal variability, and the influence of the natural attenuation processes of dilution and degradation in the Hazardous Test Area fractured-granite aquifer. Two transects of ground-water wells from the existing monitoring-site network - one perpendicular to ground-water flow (transect A-A') and another parallel to ground-water flow (transect B-B') - were selected to examine source characteristics and the spatial and temporal variability of the contaminant concentrations. Ground-water samples collected in 2005 from a larger sampling of monitoring sites than the two transects were analyzed for various tracers including major ions, trace elements, RDX degradates, dissolved gases, water isotopes, nitrate isotopes, and sulfate isotopes to examine the natural attenuation processes of dilution and degradation. Recharge entrains contaminants at the site and transports them downgradient towards the Tularosa Basin floor through a poorly connected fracture system(s). From 1996 to 2006, RDX, nitrate, and perchlorate concentrations in ground water downgradient from the Open Burn/Open Detonation site have been relatively stable. RDX, nitrate, and perchlorate in ground water from wells near the site indicate dispersed contaminant sources in and near the Open Burn/Open Detonation pits. The sources of RDX and nitrate in the pit area have shifted with time, and the shift correlates with the regrading of the south and east berms of each pit in 2002 and 2003 following closure of the site. The largest RDX concentrations were in ground water about 0.1 mile downgradient from the pits, the largest perchlorate

  18. Hydrochemical Characteristics of Groundwater in an Agricultural Area in South Korea

    NASA Astrophysics Data System (ADS)

    Kim, N.; Hamm, S.; An, J.; Lee, J.; Jang, S.

    2008-12-01

    The study area, Sacheon-Hadong area, is located in the southern part of the Korean peninsula, which is bounded by the South Sea and surrounded by the Seomjin River in the west. The study area utilized for agricultural work for a long time. That resulted in vulnerable situation of groundwater due to contamination by fertilizer, insecticide and other human activities. In addition, groundwater is in the risk of seawater intrusion because of the study area's location nearby the South Sea. In Sacheon and Hadong area, the EC values were higher in alluvial aquifer than bedrock aquifer. The higher EC values in the alluvial groundwater than the bedrock groundwater were influenced by agricultural activity in near-surface. Water types of two groundwaters belong to Ca-Cl and Na-Cl types due to saline-water influence. EC values are raised, becoming close to the coast. The correlation analysis showed that EC had positive relationship with Na+, Ca2+, Mg2+, Fe2+, Mn2+, SO42-, and Cl-, indicating mixing with seawater. In Sacheon area, nitrogen isotope ratios in the alluvial groundwater ranged between -0.40 and 12.80‰, with 0.05~2.49 mg/l of NO3-N concentration; the range of nitrogen isotopes in the bedrock groundwater was between 3.30 and 17.60‰, with 0.12~2.14 mg/l of NO3-N concentration. Nitrogen was originated from organic source in soils, manures, and domestic wastes (Mueller and Helsel, 1996; Kim and Woo, 2003). In Hadong area, the nitrogen isotopes in the alluvial groundwater ranged from -0.50 to 19.10‰, and NO3-N concentration was between 0.63 and 6.68 mg/l. And these may be originated from anthropogenic pollutants (Mueller and Helsel, 1996). In Sacheon area, average δ18O and δD in alluvial groundwater were analyzed as - 6.77‰ and -47.50‰; average isotope ratios in bedrock groundwater were -7.73‰ and - 53.46‰. In Hadong area, average δ18O and δD in the alluvial groundwater were - 7.32‰ and -49.80‰; average isotope ratios in the bedrock groundwater

  19. Modeling nitrate removal in a denitrification bed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Denitrification beds are being promoted to reduce nitrate concentrations in agricultural drainage water to alleviate the adverse environmental effects associated with nitrate pollution in surface water. In this system, water flows through a trench filled with a carbon media where nitrate is transfor...

  20. New concepts regarding the production of waterfowl and other game birds in areas of diversified agriculture

    USGS Publications Warehouse

    Nelson, H.K.; Duebbert, H.F.

    1974-01-01

    Many concepts regarding breeding ecology of waterfowl and the influences of environmental factors on annual production have changed in the past 20 years. These influences are especially pronounced in the prairie region of central North America where agriculture becomes more intensive each year. The principal task assigned to this Research Center when established in 1965 was to determine the relative impact of these influences on production and to identify those facets of breeding biology, nesting habitat requirements and other factors that may be altered to increase production on lands dedicated for this purpose. A corollary objective was to develop methods for enhancing production of waterfowl and other ground-nesting birds on private lands in agricultural areas. Some of the highlights of our findings to date, together with the results from current work of others, provide new information on waterfowl that indicates: (1) homing instincts are not as specific as indicated by earlier workers, (2) there are differences in pioneering between species, sexes and age classes, (3) strength and duration of pair bonds vary by species and age classes, (4) territorial tolerances for most species are greater than previously indicated, (5) there is differential productivity by age classes in some species, (6) there has been a gradual decline in nesting success in the prairie region the past 30 years, (7) adverse influences of intensive agriculture are increasing, (8) mammalian predation is an important factor, (9) high quality, secure nesting habitat and a complex of wetland types are the essential components of an optimum production unit, (10) the size and shape of blocks of nesting cover are important management considerations, (11) overharvest of local breeding populations is becoming a serious problem in some areas. Each of these subjects is discussed as related to research objectives and current management problems. Recommendations are presented for obtaining maximum

  1. Slash and Burn Agriculture: A Dynamic Spatio-temporal Model of Shifting Cultivation Locations and Areas

    NASA Astrophysics Data System (ADS)

    Plagge, C. E.; Frolking, S.; Chini, L. P.; Hurtt, G.

    2008-12-01

    Shifting cultivation is a form of agriculture, also known as slash-and-burn or swidden agriculture, in which a plot of forest is cleared and then cultivated continuously for several years, after which it is abandoned to revert to natural vegetation, and then is subsequently re-cleared after a longer fallow period. Shifting cultivation is an important form of agriculture because it affects soil erosion rates, canopy cover in tropical forests, nutrient deficiency in soils, and also has an impact on the global carbon cycle. Because it is generally outside of the larger economy, shifting cultivation is not well-represented in large-scale earth system analyses. We investigated a new way to model shifting cultivation which will be included in a global land-use transitions model to better quantify this type of land use, both historically and into the future. Ultimately this study will improve simulations of changes in the Earth system and will aid in the study of the carbon cycle and thus climate change. Our model calculates the area of shifting cultivation in square kilometers per half-degree grid cell, using gridded population data, the fraction of that population that is rural, the fraction of global population that practices shifting cultivation, the crop area needed per person, and the length of cultivation plus the fallow. Locations of shifting cultivation were further constrained by variables such as potential vegetation biomass density, population density, fraction of land already in use, GDP per capita, and average winter temperatures. With this model, we generated global estimates for total cultivated area, total population involved in shifting cultivation, and total shifting cultivation area including fallow lands. From this model it was estimated that the total global area of shifting cultivation in 2000 was approximately 1.5 million km2 with 90,000 km2 of that actually in cultivation by 190 million people.

  2. Monitoring of Nitrate and Pesticide Pollution in Mnasra, Morocco Soil and Groundwater.

    PubMed

    Marouane, Bouchra; Dahchour, Abdelmalek; Dousset, Sylvie; El Hajjaji, Souad

    2015-06-01

    This study evaluates the levels of nitrates and pesticides occurring in groundwater and agricultural soil in the Mnasra, Morocco area, a zone with intensive agricultural activity. A set of 108 water samples and 68 soil samples were collected from ten selected sites in the area during agricultural seasons, from May 2010 to September 2012. The results reveal that 89.7% of water samples exceeded the standard limit of nitrate concentrations for groundwater (50 mg/L). These results can be explained by the prevailing sandy nature of the soil in the area, the frequency of fertilizer usage, and the shallow level of the water table, which favors the leaching of nitrate from field to groundwater. In contrast, the selected pesticide molecules were not detected in the analysed soil and water samples; levels were below the quantification limit in all samples. This situation could be explained by the probable partial or total transformation of the molecules in soil.

  3. Monitoring of Nitrate and Pesticide Pollution in Mnasra, Morocco Soil and Groundwater.

    PubMed

    Marouane, Bouchra; Dahchour, Abdelmalek; Dousset, Sylvie; El Hajjaji, Souad

    2015-06-01

    This study evaluates the levels of nitrates and pesticides occurring in groundwater and agricultural soil in the Mnasra, Morocco area, a zone with intensive agricultural activity. A set of 108 water samples and 68 soil samples were collected from ten selected sites in the area during agricultural seasons, from May 2010 to September 2012. The results reveal that 89.7% of water samples exceeded the standard limit of nitrate concentrations for groundwater (50 mg/L). These results can be explained by the prevailing sandy nature of the soil in the area, the frequency of fertilizer usage, and the shallow level of the water table, which favors the leaching of nitrate from field to groundwater. In contrast, the selected pesticide molecules were not detected in the analysed soil and water samples; levels were below the quantification limit in all samples. This situation could be explained by the probable partial or total transformation of the molecules in soil. PMID:26459825

  4. A spatial multicriteria decision making tool to define the best agricultural areas for sewage sludge amendment.

    PubMed

    Passuello, Ana; Cadiach, Oda; Perez, Yolanda; Schuhmacher, Marta

    2012-01-01

    Sewage sludge amendment on agricultural soils has recently become a practice of heightened interest, as a consequence of sewage sludge production increase. This practice has benefits to soil and crops, however it may also lead to environmental contamination, depending on the characteristics of the fields. In order to define the suitability of the different agricultural fields to receive sewage sludge, a spatial tool is proposed. This tool, elaborated in GIS platform, aggregates different criteria regarding human exposure and environmental contamination. The spatial tool was applied to a case study in the region of Catalonia (NE of Spain). Within the case study, each step of the tool development is detailed. The results show that the studied region has different suitability degrees, being the appropriate areas sufficient for receiving the total amount of sewage sludge produced. The sensitivity analysis showed that "groundwater contamination", "distance to urban areas", "metals concentration in soil" and "crop type" are the most important criteria of the evaluation. The developed tool successfully tackled the problem, providing a comprehensive procedure to evaluate agricultural land suitability to receive sewage sludge as an organic fertilizer. Also, the tool implementation gives insights to decision makers, guiding them to more confident decisions, based on an extensive group of criteria.

  5. Assessment of agricultural drought in rainfed cereal production areas of northern China

    NASA Astrophysics Data System (ADS)

    Li, Rui; Tsunekawa, Atsushi; Tsubo, Mitsuru

    2015-10-01

    Agricultural drought assessment is an important tool for water management in water-scarce regions such as Inner Mongolia and northeastern China. Conventional methods have difficulty of clarifying long-term influences of drought on regional agricultural production. To accurately evaluate regional agricultural drought, we assessed the performance of drought indices by constructing a new assessment framework with three components: crop model calibration and validation, drought index calculation, and index assessment (standard period setting, mean value and agreement assessments). The Environmental Policy Integrated Climate (EPIC) model simulated well of county-level wheat and maize yields in the nine investigated counties. We calculated a major crop-specific index yield reduction caused by water stress (WSYR) in the EPIC crop model, by relating potential and rainfed yields. Using 26 agricultural drought cases, we compared WSYR with two meteorological drought indices: precipitation (P) and aridity index (AI). The results showed that WSYR had greater agreement (85 %) than either the precipitation (65 %) or aridity index (68 %). The temporal trend of the indices over the period 1962-2010 was tested using three approaches. The result via WSYR revealed a significant increase in the trend of agricultural drought in drought-prone counties, which could not be shown by the precipitation and aridity indices. Total number of dry year via WSYR from 1990s to 2000s increases more sharply than via P or AI. As shown by WSYR, the number of dry years in northeastern China and Inner Mongolia is generally increasing, particularly after the 2000s, in the western part of the study area. The study reveals the usefulness of the framework for drought index assessment and indicates the potential of WSYR and possible drought cases for drought classification.

  6. The United States Department Of Agriculture Northeast Area-wide Tick Control Project: history and protocol.

    PubMed

    Pound, Joe Mathews; Miller, John Allen; George, John E; Fish, Durland

    2009-08-01

    The Northeast Area-wide Tick Control Project (NEATCP) was funded by the United States Department of Agriculture (USDA) as a large-scale cooperative demonstration project of the USDA-Agricultural Research Service (ARS)-patented 4-Poster tick control technology (Pound et al. 1994) involving the USDA-ARS and a consortium of universities, state agencies, and a consulting firm at research locations in the five states of Connecticut (CT), Maryland (MD), New Jersey (NJ), New York (NY), and Rhode Island (RI). The stated objective of the project was "A community-based field trial of ARS-patented tick control technology designed to reduce the risk of Lyme disease in northeastern states." Here we relate the rationale and history of the technology, a chronological listing of events leading to implementation of the project, the original protocol for selecting treatment, and control sites, and protocols for deployment of treatments, sampling, assays, data analyses, and estimates of efficacy.

  7. Nitrate Isotopes in Precipitation to Distinguish NOx Sources, Atmospheric Processes, and Source Areas in the United States

    NASA Astrophysics Data System (ADS)

    Elliott, E. M.; Kendall, C.; Burns, D. A.; Boyer, E. W.; Harlin, K.; Wankel, S. D.; Butler, T. J.; Carlton, R.

    2006-05-01

    Atmospheric deposition is a major source of nitrate exported to coastal waters and a key contributor to eutrophication of surface waters worldwide. In order to reduce N loads to surface waters, it is important to understand the relative contributions of major NOx sources to wet and dry deposition to watersheds. In the United States, the two largest NOx sources are vehicular emissions (54 percent) and stationary fuel combustion (40 percent). Reducing emissions from these sources is critical to improving air and surface water quality. However, using nitrate concentration data alone, it is difficult to establish relationships between individual NOx sources and wet deposition of nitrate. Previous research has shown that different NOx sources can have different isotopic compositions and can be used to identify NOx sources to wet deposition. To address this research need, we have completed the first national survey of nitrate isotopes in wet deposition using samples collected by the National Atmospheric Deposition Program (NADP). Archived samples (2000) from 156 NADP sites across the United States were pooled into bimonthly, volume-weighted composites and analyzed for δ15N, δ18O, and mass-independent Δ17O of nitrate using the microbial denitrifier method. Nitrate concentrations in the archived samples were stable over several years, indicating that the probability of isotopic fractionation associated with sample storage is very low. We present spatial and temporal variations in both N and O isotopes, and investigate the critical question of whether these variations are a function of atmospheric processes or NOx source contributions. In our analyses (n=883), we determined that δ15N values ranged from -11 to +3 ‰, whereas δ18O values ranged from +63 to +94 ‰. On average, both δ15N and δ18O values are higher in the winter than in the summer (approximately 2 and 10 permil higher, respectively). In the Northeastern and Mid-Atlantic US, we observed strong

  8. Estimating Hydrologic Fluxes, Crop Water Use, and Agricultural Land Area in China using Data Assimilation

    NASA Astrophysics Data System (ADS)

    Smith, Tiziana; McLaughlin, Dennis B.; Hoisungwan, Piyatida

    2016-04-01

    Crop production has significantly altered the terrestrial environment by changing land use and by altering the water cycle through both co-opted rainfall and surface water withdrawals. As the world's population continues to grow and individual diets become more resource-intensive, the demand for food - and the land and water necessary to produce it - will continue to increase. High-resolution quantitative data about water availability, water use, and agricultural land use are needed to develop sustainable water and agricultural planning and policies. However, existing data covering large areas with high resolution are susceptible to errors and can be physically inconsistent. China is an example of a large area where food demand is expected to increase and a lack of data clouds the resource management dialogue. Some assert that China will have insufficient land and water resources to feed itself, posing a threat to global food security if they seek to increase food imports. Others believe resources are plentiful. Without quantitative data, it is difficult to discern if these concerns are realistic or overly dramatized. This research presents a quantitative approach using data assimilation techniques to characterize hydrologic fluxes, crop water use (defined as crop evapotranspiration), and agricultural land use at 0.5 by 0.5 degree resolution and applies the methodology in China using data from around the year 2000. The approach uses the principles of water balance and of crop water requirements to assimilate existing data with a least-squares estimation technique, producing new estimates of water and land use variables that are physically consistent while minimizing differences from measured data. We argue that this technique for estimating water fluxes and agricultural land use can provide a useful basis for resource management modeling and policy, both in China and around the world.

  9. Environmental setting of benchmark streams in agricultural areas of eastern Wisconsin

    USGS Publications Warehouse

    Rheaume, S.J.; Stewart, J.S.; Lenz, B.N.

    1996-01-01

    Differences in land use/land cover, and riparian vegetation and instream habitat characteristics are presented. Summaries of field measurements of water temperature, pH, specific conductance and concentrations of dissolved oxygen, total organic plus ammonia nitrogen, dissolved ammonium, nitrate plus nitrte as nitrogen, total phosphorus, dissolved orthophosphate, and atrazine are listed. Concentrations of dissolved oxygen for the sampled streams ranged from 6 A to 14.3 and met the standards set by the Wisconsin Department of Natural Resources (WDNR) for supporting fish and aquatic life. Specific conductance ranged from 98 to 753 u,Scm with values highest in RHU's 1 and 3, where streams are underlain by carbonate bedrock. Median pH did not vary greatly among the four RHU's and ranged from 6.7 to 8.8 also meeting the WDNR standards. Concentrations of total organic plus ammonia nitrogen, dissolved ammonium, total phosphorus, and dissolved orthophosphate show little variation between streams and are generally low, compared to concentrations measured in agriculturally-affected streams in the same RHU's during the same sampling period. Concentrations of the most commonly used pesticide in the study unit, atrazine, were low in all streams, and most concentrations were below trn 0.1 u,g/L detection limit. Riparian vegetation for the benchmark streams were characterized by lowland species of the native plant communities described by John T. Curtis in the "Vegetation of Wisconsin." Based on the environmental setting and water-quality information collected to date, these streams appear to show minimal adverse effects from human activity.

  10. Mercury Cycling in Agricultural and Non-agricultural Wetlands in the Yolo Bypass Wildlife Area, California: Water Column Processes

    NASA Astrophysics Data System (ADS)

    Fleck, J. A.; Alpers, C. N.; Downing, B. D.; Saraceno, J.; Stephenson, M.; Aiken, G. R.; Bergamaschi, B. A.; Stricker, C.

    2007-12-01

    Organic matter (OM) plays a significant role in mercury (Hg) cycling. For instance, aromatic dissolved OM can enhance Hg solubility leading to greater cycling in the water column whereas bioavailable forms of OM may enhance Hg methylation by increasing the microbial activity of Hg-methylating bacteria. Differences in wetland management (e.g. fertilization, plant residue, water depth and movement) can influence the character of OM within the wetland, thus affecting Hg cycling as well. This study is investigating the role of OM in Hg cycling over a wide range of time scales and wetland management practices within the Yolo Bypass Wildlife Area, near Sacramento, California. We are comparing Hg and methylmercury (MeHg) concentrations in the water columns of three agricultural field types (wild rice, white rice, and shallow-flooded fallow) with those in two non-agricultural field types (seasonal and permanent wetlands). The time scales over which variations in Hg and MeHg concentrations are being investigated range from diurnal variations caused by fluctuations in photolytic reactions and microbial activity to seasonal variations caused by plant growth, land management, climate, and fertilization. We relate those concentration fluctuations to the dominant processes affecting OM cycling in the fields. We further evaluate the possible influence of S-bearing fertilizers, such as ammonium sulfate and zinc sulfate, on Hg methylation because of the role that sulfur plays in Hg cycling and Hg-OM interactions. Preliminary results indicate that dissolved OM (DOM) concentrations (operationally defined using a filter with 0.45 ìm pore diameter) increased from 9 milligrams of carbon per liter (mg-C/L) at inflow stations to as high as 30 mg-C/L within the water column of the wetlands. Based on measured optical properties, OM in these wetlands appears to be derived from a mixture of algal activity, plant exudates, and diffusion from the flooded soils, with the proportion of each

  11. Decadal-scale changes of nitrate in ground water of the United States, 1988-2004

    USGS Publications Warehouse

    Rupert, M.G.

    2008-01-01

    This study evaluated decadal-scale changes of nitrate concentrations in groundwater samples collected by the USGS National Water-Quality Assessment Program from 495 wells in 24 well networks across the USA in predominantly agricultural areas. Each well network was sampled once during 1988-1995 and resampled once during 2000-2004. Statistical tests of decadal-scale changes of nitrate concentrations in water from all 495 wells combined indicate there is a significant increase in nitrate concentrations in the data set as a whole. Eight out of the 24 well networks, or about 33%, had significant changes of nitrate concentrations. Of the eight well networks with significant decadal-scale changes of nitrate, all except one, the Willamette Valley of Oregon, had increasing nitrate concentrations. Median nitrate concentrations of three of those eight well networks increased above the USEPA maximum contaminant level of 10 mg L-1. Nitrate in water from wells with reduced conditions had significantly smaller decadal-scale changes in nitrate concentrations than oxidized and mixed waters. A subset of wells had data on ground water recharge date; nitrate concentrations increased in response to the increase of N fertilizer use since about 1950. Determining ground water recharge dates is an important component of a ground water trends investigation because recharge dates provide a link between changes in ground water quality and changes in land-use practices. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  12. Comparison of DDT and its metabolites concentrations in cow milk from agricultural and industrial areas.

    PubMed

    Kuba, Jarosław; Tomza-Marciniak, Agnieszka; Pilarczyk, Bogumiła; Tarasewicz, Natalia; Pilarczyk, Renata; Ligocki, Marek

    2015-01-01

    The risk of pesticidal intoxication in humans is severe, especially because of the strongly negative impact on human health. The consequences of the exposure to these substances may include cancerogenesis or endocrine abnormalities resulting for example in decreased fertility. Therefore, the aim of our study was to evaluate the content of dichlorodiphenyltrichloroethane (DDT) and its metabolites in cow milk from two regions of Poland, varying by level of industrialization. Samples were collected from agricultural (n = 25) and industrial (n = 25) areas, and the concentrations of DDT and its metabolites were evaluated by gas chromatography. Residues of DDT were detected in all the milk samples tested, mostly in the samples from the agricultural area, where a total DDT median concentration reached 0.336 μg L(-1). In the milk samples from the industrial area, the median concentration was lower, at 0.131 μg L(-1). 4,4'-DDT was the main metabolite, constituting 83% of total DDT metabolites. Although none of the samples exceeded the level above which they should be considered dangerous, the results showed that the problem of DDT had not diminished and so should be constantly monitored.

  13. [Catchment scale risk assessment and critical source area identification of agricultural phosphorus loss].

    PubMed

    Li, Qi; Chen, Li-Ding; Qi, Xin; Zhang, Xin-Yu; Ma, Yan

    2007-09-01

    Agricultural non-point source phosphorus pollution is a severe problem for rural water bodies in China, but hard to control directly because of its special characteristics. In this paper, an approach on the catchment scale risk assessment and critical source area identification of agricultural phosphorus loss in northern China was made, based on the catchment scale phosphorus ranking scheme and the method proposed by Gburek et al. Eight factors were selected and weighed in the modified catchment scale phosphorus ranking scheme, and the phosphorus loss risk rating of each factor was adjusted based on the current professional standards and the actual circumstances in China. The areas with ' high' risk rating of phosphorus loss in definite catchment were the critical source areas for non-point source phosphorous pollution control in that catment. The availability of obtained data and the quantification of the assessment were taken into account in the new scheme, and GIS technique and geostatistics were used for confirming the factors. Therefore, the new scheme had definite operability and practicability. PMID:18062300

  14. Virus in Groundwater: Characterization of transport mechanisms and impacts on an agricultural area in Uruguay

    NASA Astrophysics Data System (ADS)

    Gamazo, P. A.; Colina, R.; Victoria, M.; Alvareda, E.; Burutaran, L.; Ramos, J.; Lopez, F.; Soler, J.

    2014-12-01

    In many areas of Uruguay groundwater is the only source of water for human consumption and for industrial-agricultural economic activities. Traditionally considered as a safe source, due to the "natural filter" that occurs in porous media, groundwater is commonly used without any treatment. The Uruguayan law requires bacteriological analysis for most water uses, but virological analyses are not mentioned in the legislation. In the Salto district, where groundwater is used for human consumption and for agricultural activities, bacterial contamination has been detected in several wells but no viruses analysis have been performed. The Republic University (UDELAR), with the support of the National Agency for Research and Innovation (ANII), is studying the incidence of virus in groundwater on an intensive agriculture area of the Salto district. In this area water is pumped from the "Salto Aquifer", a free sedimentary aquifer. Below this sedimentary deposit is the "Arapey" basaltic formation, which is also exploited for water productions on its fractured zones. A screening campaign has been performed searching for bacterial and viral contamination. Total and fecal coliforms have been found on several wells and Rotavirus and Adenovirus have been detected. A subgroup of the screening wells has been selected for an annual survey. On this subgroup, besides bacteria and viruses analysis, a standard physical and chemical characterization was performed. Results show a significant seasonal variation on microbiological contamination. In addition to field studies, rotavirus circulation experiments on columns are being performed. The objective of this experiments is to determinate the parameters that control virus transport in porous media. The results of the study are expected to provide an insight into the impacts of groundwater on Salto's viral gastroenterocolitis outbreaks.

  15. Isotopic Systematics (U, nitrate and Sr) of the F-Area Acidic Contamination Plume at the Savannah River Site: Clues to Contaminant History and Mobility

    NASA Astrophysics Data System (ADS)

    Christensen, J. N.; Conrad, M. E.; Bill, M.; Denham, M.; Wan, J.; Rakshit, S.; Stringfellow, W. T.; Spycher, N.

    2010-12-01

    Seepage basins in the F-Area of the Savannah River Site were used from 1955 to 1989 for the disposal of low-level radioactive acidic (ave. pH ˜2.9) waste solutions from site operations involving irradiated uranium billets and other materials used in the production of radionuclides. These disposal activities resulted in a persistent acidic groundwater plume (pH as low as 3.2) beneath the F-Area including contaminants such as tritium, nitrate, 90Sr, 129I and uranium and that has impinged on surface water (Four Mile Branch) about 600 m from the basins. After cessation of disposal in 1989, the basins were capped in 1991. Since that time, remediation has consisted of a pump-and-treat system that has recently been replaced with in situ treatment using a funnel-and-gate system with injection of alkaline solutions in the gates to neutralize pH. In order to delineate the history of contamination and the current mobility and fate of contaminants in F-Area groundwater, we have undertaken a study of variations in the isotopic compositions of U (234U/238U, 235U/238U, 236U/238U), Sr (87Sr/86Sr) and nitrate (δ15N, δ18O) within the contaminant plume. This data can be used to trace U transport within the plume, evaluate chemical changes of nitrate, and potentially track plume/sediment chemical interaction and trace the migration of 90Sr. We have analyzed a suite of groundwater samples from monitoring wells, as well as pore-water samples extracted from aquifer sediment cores to map out the isotopic variation within the plume. The isotopic compositions of U from well samples and porewater samples are all consistent with the variable burn-up of depleted U. The variation in U isotopic composition requires at least three different endmembers, without any significant influence of background natural U. The δ15N and δ18O of nitrate from F-Area plume groundwater are distinct both from natural and unaltered synthetic nitrate, and likely represents fractionation due to waste volume

  16. Assessing the relationship between groundwater nitrate and animal feeding operations in Iowa (USA).

    PubMed

    Zirkle, Keith W; Nolan, Bernard T; Jones, Rena R; Weyer, Peter J; Ward, Mary H; Wheeler, David C

    2016-10-01

    Nitrate-nitrogen is a common contaminant of drinking water in many agricultural areas of the United States of America (USA). Ingested nitrate from contaminated drinking water has been linked to an increased risk of several cancers, specific birth defects, and other diseases. In this research, we assessed the relationship between animal feeding operations (AFOs) and groundwater nitrate in private wells in Iowa. We characterized AFOs by swine and total animal units and type (open, confined, or mixed), and we evaluated the number and spatial intensities of AFOs in proximity to private wells. The types of AFO indicate the extent to which a facility is enclosed by a roof. Using linear regression models, we found significant positive associations between the total number of AFOs within 2km of a well (p trend <0.001), number of open AFOs within 5km of a well (p trend <0.001), and number of mixed AFOs within 30km of a well (p trend <0.001) and the log nitrate concentration. Additionally, we found significant increases in log nitrate in the top quartiles for AFO spatial intensity, open AFO spatial intensity, and mixed AFO spatial intensity compared to the bottom quartile (0.171log(mg/L), 0.319log(mg/L), and 0.541log(mg/L), respectively; all p<0.001). We also explored the spatial distribution of nitrate-nitrogen in drinking wells and found significant spatial clustering of high-nitrate wells (>5mg/L) compared with low-nitrate (≤5mg/L) wells (p=0.001). A generalized additive model for high-nitrate status identified statistically significant areas of risk for high levels of nitrate. Adjustment for some AFO predictor variables explained a portion of the elevated nitrate risk. These results support a relationship between animal feeding operations and groundwater nitrate concentrations and differences in nitrate loss from confined AFOs vs. open or mixed types. PMID:27277210

  17. Assessing the relationship between groundwater nitrate and animal feeding operations in Iowa (USA).

    PubMed

    Zirkle, Keith W; Nolan, Bernard T; Jones, Rena R; Weyer, Peter J; Ward, Mary H; Wheeler, David C

    2016-10-01

    Nitrate-nitrogen is a common contaminant of drinking water in many agricultural areas of the United States of America (USA). Ingested nitrate from contaminated drinking water has been linked to an increased risk of several cancers, specific birth defects, and other diseases. In this research, we assessed the relationship between animal feeding operations (AFOs) and groundwater nitrate in private wells in Iowa. We characterized AFOs by swine and total animal units and type (open, confined, or mixed), and we evaluated the number and spatial intensities of AFOs in proximity to private wells. The types of AFO indicate the extent to which a facility is enclosed by a roof. Using linear regression models, we found significant positive associations between the total number of AFOs within 2km of a well (p trend <0.001), number of open AFOs within 5km of a well (p trend <0.001), and number of mixed AFOs within 30km of a well (p trend <0.001) and the log nitrate concentration. Additionally, we found significant increases in log nitrate in the top quartiles for AFO spatial intensity, open AFO spatial intensity, and mixed AFO spatial intensity compared to the bottom quartile (0.171log(mg/L), 0.319log(mg/L), and 0.541log(mg/L), respectively; all p<0.001). We also explored the spatial distribution of nitrate-nitrogen in drinking wells and found significant spatial clustering of high-nitrate wells (>5mg/L) compared with low-nitrate (≤5mg/L) wells (p=0.001). A generalized additive model for high-nitrate status identified statistically significant areas of risk for high levels of nitrate. Adjustment for some AFO predictor variables explained a portion of the elevated nitrate risk. These results support a relationship between animal feeding operations and groundwater nitrate concentrations and differences in nitrate loss from confined AFOs vs. open or mixed types.

  18. [Agricultural production responsibility system and the work of family planning in the rural area].

    PubMed

    Zhu, M

    1982-09-29

    With the establishment of the agricultural production responsibility system, the entire agricultural management and economic system has undergone great changes, and family planning in rural areas has met with many difficulties. Because of this responsibility system, households with more manpower seem to become wealthy more rapidly than others. An existing belief among the rural population is that more children will provide a larger labor force and thus more income. Birth control and family planning are therefore becoming more difficult. In order to change existing beliefs, a comprehensive ideological education for peasants is needed so that they may understand the question of birth control from the viewpoints of national interests. Economic rewards and administrative restrictions may be used as necessary birth control measures. Agricultural production and family planning can be managed well if there is close contact and cooperation between the cadres and the masses. Extra care and benefits should be given to women of childbearing age who undergo birth control operations and agree to a single child in each household. Welfare programs for the masses, such as kindergartens and nursing homes must be established in order to reduce their worries. In addition, efforts are needed to study the new situation and solve new problems. The goal of controlling the rural population growth should be achiefed through practical work and experience.

  19. Agricultural runoff fuels large phytoplankton blooms in vulnerable areas of the ocean

    NASA Astrophysics Data System (ADS)

    Michael Beman, J.; Arrigo, Kevin R.; Matson, Pamela A.

    2005-03-01

    Biological productivity in most of the world's oceans is controlled by the supply of nutrients to surface waters. The relative balance between supply and removal of nutrients-including nitrogen, iron and phosphorus-determines which nutrient limits phytoplankton growth. Although nitrogen limits productivity in much of the ocean, large portions of the tropics and subtropics are defined by extreme nitrogen depletion. In these regions, microbial denitrification removes biologically available forms of nitrogen from the water column, producing substantial deficits relative to other nutrients. Here we demonstrate that nitrogen-deficient areas of the tropical and subtropical oceans are acutely vulnerable to nitrogen pollution. Despite naturally high nutrient concentrations and productivity, nitrogen-rich agricultural runoff fuels large (54-577km2) phytoplankton blooms in the Gulf of California. Runoff exerts a strong and consistent influence on biological processes, in 80% of cases stimulating blooms within days of fertilization and irrigation of agricultural fields. We project that by the year 2050, 27-59% of all nitrogen fertilizer will be applied in developing regions located upstream of nitrogen-deficient marine ecosystems. Our findings highlight the present and future vulnerability of these ecosystems to agricultural runoff.

  20. Hydrologic Conditions and Quality of Rainfall and Storm Runoff in Agricultural and Rangeland Areas in San Patricio County, Texas, 2000-2001

    USGS Publications Warehouse

    Ockerman, Darwin J.

    2002-01-01

    During 2000?2001, rainfall and runoff were monitored in one mixed agricultural watershed and two rangeland watersheds in San Patricio County, located in the Coastal Bend area of South Texas. During this period, five rainfall samples were collected and analyzed for selected nutrients. Ten runoff samples from nine runoff events were collected at the three watershed monitoring stations. Runoff samples were analyzed for selected nutrients, major ions, trace elements, pesticides, and bacteria. Study area rainfall during 2000 and 2001 was 33.27 and 28.20 inches, respectively, less than the long-term average annual of 36.31 inches. Total runoff from the study area watersheds during 2000?2001 was 2.46 inches; the regional average is about 2 inches per year. Rainfall and runoff during the study period was typical of historical patterns, with periods of below average rainfall interspersed with extreme events. Three individual storm events accounted for about 29 percent of the total rainfall and 86 percent of the total runoff during 2000?2001. Runoff concentrations of nutrients, major ions, and trace elements generally were larger in the mixed agricultural watershed than runoff concentrations in the rangeland watersheds. Pesticides were detected in two of eight runoff samples. Three pesticides (atrazine, deethylatrazine, and trifluralin) were detected in very small concentrations; only deethylatrazine was detected in a concentration greater than the laboratory minimum reporting level. Bacteria in agricultural and rangeland runoff is a potential water-quality concern as all fecal coliform and E. coli densities in the runoff samples exceeded Texas Surface Water Quality Standards for receiving waters. However, runoff and relatively large bacteria densities represent very brief and infrequent conditions, and the effect on downstream water is not known. Rainfall deposition is a major source of nitrogen delivered to the study area. Rainfall nitrogen (mostly ammonia and nitrate

  1. Land degradation monitoring in Braila agricultural area using RADARSAT2 data

    NASA Astrophysics Data System (ADS)

    Poenaru, Violeta; Badea, Alexandru; Dana Negula, Iulia; Moise, Cristian; Cimpeanu, Sorin

    2016-08-01

    The estimation of degradation in agricultural lands from fully polarimetric synthetic aperture radar (SAR) data at C-band using differential SAR interferometry is investigated. To this aim, we used a dataset of high resolution SAR images collected in the joint ESA-CSA SOAR Europe-16605 scientific proposal framework that have been processed through the persistent scattering - DInSAR technique. Moreover, to improve PSInSAR analysis, we used polarimetric optimization method on multi-temporal polarimetric SAR data. Optimization is based on the selection of the most stable scattering mechanism over time since the unitary complex column vector is related to the geometric and electromagnetic features of the target. We applied this method on a dataset including 14 compact polarization SAR data (HH/HV/VV) acquired by RADARSAT2 from August 2014 to November 2015 over Braila agricultural area. The area has been affected by land degradation due to salinization and irrigation water overexploitation. The results reveal that the use of an optimum scattering mechanism provides a significant improvement in increasing the PS density and hence the density of the pixels with valid deformation results with respect to single-pol data (about 50% more than single channel datasets).

  2. Antioxidant response of three Tillandsia species transplanted to urban, agricultural, and industrial areas.

    PubMed

    Bermudez, Gonzalo M A; Pignata, María Luisa

    2011-10-01

    To evaluate the physiological response of Tillandsia capillaris Ruiz & Pav. f. capillaris, T. recurvata L., and T. tricholepis Baker to different air pollution sources, epiphyte samples were collected from a noncontaminated area in the province of Córdoba (Argentina) and transplanted to a control site as well as three areas categorized according to the presence of agricultural, urban, and industrial (metallurgical and metal-mechanical) emission sources. A foliar damage index (FDI) was calculated with the physiological parameters chlorophyll a, chlorophyll b, malondialdehyde (MDA), hydroperoxyconjugated dienes, sulfur (S) content, and dry weight-to-fresh weight ratio. In addition, electrical conductivity (E-cond), relative water content (RWC), dehydration kinetics (Kin-H(2)O), total phenols (T-phen), soluble proteins (S-prot), and activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase were determined. The parameters E-cond, FDI, SOD, RWC, and Kin-H(2)O can serve as suitable indicators of agricultural air pollution for T. tricholepis and T. capillaris, and CAT, Kin-H(2)O, and SOD can do the same for T. recurvata. In addition, MDA, T-phen, and S-prot proved to be appropriate indicators of urban pollution for T. recurvata. Moreover, FDI, E-cond, and SOD for T. recurvata and MDA for T. tricholepis, respectively, could be used to detect deleterious effects of industrial air pollution.

  3. Heavy metals bioaccumulation in Berseem (Trifolium alexandrinum) cultivated in areas under intensive agriculture, Punjab, India.

    PubMed

    Bhatti, Sandip Singh; Sambyal, Vasudha; Nagpal, Avinash Kaur

    2016-01-01

    Berseem (Trifolium alexandrinum) is one of the main fodder crops of Punjab, India. But due to the heavy metal contamination of agricultural soils by anthropogenic activities, there is rise in metal bioaccumulation in crops like Berseem. In addition to human influence, heavy metal contents in soil are highly dependent on soil characteristics also. Therefore a study was conducted in areas having intensive agricultural practices to analyze physico-chemical characteristics of soils under Berseem cultivation and heavy metal bioaccumulation in Berseem. The studied soils were alkaline, sandy in texture and low in soil organic matter. Among the studied heavy metals (Cr, Cu, Cd, Co and Pb) in soil and Berseem, Cr content in Berseem was found to be above maximum permissible limits. Soil to Berseem metal bioaccmulation factor (BAF) was above 1 for Cr, Cu, Cd and Co in many samples and highest BAF was found for Co (4.625). Hence it can be concluded that Berseem from studied areas was unsafe for animal consumption.

  4. Heavy metals bioaccumulation in Berseem (Trifolium alexandrinum) cultivated in areas under intensive agriculture, Punjab, India.

    PubMed

    Bhatti, Sandip Singh; Sambyal, Vasudha; Nagpal, Avinash Kaur

    2016-01-01

    Berseem (Trifolium alexandrinum) is one of the main fodder crops of Punjab, India. But due to the heavy metal contamination of agricultural soils by anthropogenic activities, there is rise in metal bioaccumulation in crops like Berseem. In addition to human influence, heavy metal contents in soil are highly dependent on soil characteristics also. Therefore a study was conducted in areas having intensive agricultural practices to analyze physico-chemical characteristics of soils under Berseem cultivation and heavy metal bioaccumulation in Berseem. The studied soils were alkaline, sandy in texture and low in soil organic matter. Among the studied heavy metals (Cr, Cu, Cd, Co and Pb) in soil and Berseem, Cr content in Berseem was found to be above maximum permissible limits. Soil to Berseem metal bioaccmulation factor (BAF) was above 1 for Cr, Cu, Cd and Co in many samples and highest BAF was found for Co (4.625). Hence it can be concluded that Berseem from studied areas was unsafe for animal consumption. PMID:27026870

  5. Practical split-window algorithm for retrieving land surface temperature over agricultural areas from ASTER data

    NASA Astrophysics Data System (ADS)

    Wang, Songhan; He, Longhua

    2014-01-01

    A practical split-window algorithm which involves two parameters (transmittance and emissivity) utilized to retrieve land-surface temperature over agricultural areas from the Advanced Spaceborne Thermal Emission and Reflection Radiometer data is presented. First, by calculating the relationship between thermal radiation intensity and temperature, the Planck function is simplified using exponential function which is applied to deduce the split-window algorithm. Second, how to obtain transmittance from water vapor content and the method for estimating emissivity using normalized difference vegetation index are discussed in detail. Sensitivity analysis demonstrates that the algorithm is not sensitive to these two parameters. Finally, a standard atmospheric simulation method has been used to validate the proposed algorithm, and comparison between the algorithm and the prior study has been carried out. The results indicate that the average accuracy is 0.32 K for the case without error in both transmittance and emissivity, which is better than the prior algorithm. The accuracy is also 0.32 K when the transmittance is computed from the water content by piecewise cubic polynomial fit. The accuracy is about 0.30 K˜0.33 K corresponding to different Pv (Pv is the proportion of vegetation) values, which indicates that this algorithm is suitable for different land surface types over agricultural areas.

  6. Cosmo-SkyMed and RADARSAT2 image investigation for the monitoring of agricultural areas

    NASA Astrophysics Data System (ADS)

    Paloscia, S.; Pettinato, S.; Santi, E.; Notarnicola, C.; Greifeneder, F.; Cuozzo, G.; Nicolini, I.; Demir, B.; Bruzzone, L.

    2015-10-01

    This research aims at investigating the backscatter sensitivity at C and X band to the characteristics of agricultural surfaces and analyzing the integration of these data collected from Radarsat2 (RS2) and COSMO-SkyMed (CSK) systems on tree agricultural test areas in Italy (San Pietro Capofiume, in Emilia Romagna, Sesto Fiorentino, in Tuscany, and Mazia Valley, in South Tyrol). A preliminary test of the sensitivity of SAR signal to the soil and vegetation characteristics was first carried out by also comparing data from previous experiments. From these results, it can be concluded that X-band data are mainly sensitive to vegetation structure and biomass, and to soil moisture of bare or slightly vegetate soils, whereas C-band images could provide valuable information for the retrieval of soil moisture, even in vegetation covered soils. Two retrieval algorithms were implemented for estimating the main geophysical parameters, namely soil moisture content (SMC) and vegetation biomass (PWC) from these sensors. Over Sesto Fiorentino area, an algorithm based on Artificial Neural Network (ANN) technique was implemented for estimating both SMC of bare or scarcely vegetated soil and vegetation biomass of wheat crops at X band. On the South-Tyrol area, a SMC retrieval approach based on the Support Vector Regression methodology, which was already tested in this area using C-band data from ENVISAT/ASAR data, was adopted. This algorithm integrated data at both X and C bands showing encouraging results, even though further investigations shall be carried out on a larger time-series and larger set of samples.

  7. Use of thermal inertia determined by HCMM to predict nocturnal cold prone areas in Florida. [The Everglades agricultural area, Lake Okeechobee, and the Suwanee River basin

    NASA Technical Reports Server (NTRS)

    Allen, L. H., Jr. (Principal Investigator); Chen, E.; Martsolf, J. D.; Jones, P. H.

    1981-01-01

    Transparencies, prints, and computer compatible tapes of temperature differential and thermal inertia for the winter of 1978 to 1979 were obtained. Thermal inertial differences in the South Florida depicted include: drained organic soils of the Everglades agricultural area, undrained organic soils of the managed water conservation areas of the South Florida water management district, the urbanized area around Miami, Lake Okeechobee, and the mineral soil west of the Everglades agricultural area. The range of wetlands and uplands conditions within the Suwanee River basin was also identified. It is shown that the combination of wetlands uplands surface features of Florida yield a wide range of surface temperatures related to wetness of the surface features.

  8. USE OF TRACER INJECTION EXPERIMENTS TO QUANTIFY NITRATE LOSS IN TWO ADJACENT WETLAND STREAMS DRAINING AN AGRICULTURAL FIELD IN THE GEORGIA PIEDMONT

    EPA Science Inventory

    This study investigated the extent to which nitrate was removed from and/or stored in a small wetland depression downgradient of a 10-ha cattle rotational grazing pasture and a 2.5-ha cropped catchment at the USDA-ARS J. Phil Campbell Sr. Natural Resource Conservation Center in W...

  9. Management of water for irrigation agriculture in semi-arid areas: Problems and prospects

    NASA Astrophysics Data System (ADS)

    Mvungi, A.; Mashauri, D.; Madulu, N. F.

    Most of the Mwanga district is classified as semi-arid with a rainfall range of 300 and 600 mm. Rainfall patterns in the district are unpredictable and are subject to great fluctuations. Like other semi-arid areas, the district is characterized with land degradation, unreliable rainfall, repeated water shortage, periodic famine, overgrazing, dry land cultivation in the marginal areas and heavy competition for limited biomass between farmers and cattle. Vulnerability here is high due to unreliability of weather. The people of Mwanga are dependent on agriculture for their livelihood. However agriculture is difficult in the area due to inadequate rainfall. For a very long time the people have been dependent on irrigation agriculture to ensure food security. Of late the traditional irrigation system is on the decline threatening food security in the area. This paper examines the state and status of the irrigation canal system in Mwanga district with the view of recommending ways in which it can be improved. The study used participatory, survey and in-depth interviews to obtain both quantitative and qualitative data. The major findings are that social, political, environmental and demographic bases that supported the traditional irrigation system have changed drastically. As a corollary to this, the cultural and religious belief systems that supported and guided the traditional canal system management have been replaced by mistrust and corruption in water allocation. In addition the ownership and management system of the water resources that was vested in the initiator clans has changed and now water user groups own the canals/furrows but they do not own the water sources. This has rendered the control of the water sources difficult if not impossible. Currently the system is faced by a number of problems including shortage of water and poor management as demand for water increases and this has led to serious conflicts among and between crop producers and pastoralists

  10. Flow and geochemistry along shallow ground-water flowpaths in an agricultural area in southeastern Wisconsin

    USGS Publications Warehouse

    Saad, D.A.; Thorstenson, D.C.

    1998-01-01

    Ground water recharging at mid- and downgradient wells is oxic and contains dissolved nitrate, whereas the ground water discharging to the stream is anoxic and contains dissolved ammonium. Redox environments were defined at each well on the basis of relative concentrations of various dissolved redox-active species. Chemically permissible flowpaths inferred from the observed sequence of redox environments at well sites are consistent with flowpaths in the ground-water flow model. The transition from nitrate in recharging groun

  11. Effects of Stream Channel Characteristics on Nitrate Delivery to Streams and In-Stream Denitrification Rates, Raccoon River, Iowa

    NASA Astrophysics Data System (ADS)

    Prestegaard, K. L.; O'Connell, M.

    2004-05-01

    Streams in agricultural areas often exhibit significant channel and sediment modifications; they are often incised and transport more fine sediment than non-agricultural streams. These channel characteristics can influence stream water quality by modifying surface-groundwater interactions. In the Raccoon River basin, channel incision increases the delivery of nitrate from the groundwater to the streams. The sandy in-stream sediments, however, serve as very effective sites for in-stream denitrification. Nitrate delivery and in-stream denitrification was examined in 3 subwatersheds of the Raccoon River. Stream morphology, water quality, and sediment characteristics were measured at 35 sites with varying land uses. Headwater stream nitrate concentration increased with percent row crops and the amount of channel incision. Downstream sites showed a wide variation in nitrate concentration with land use. Stream nitrate concentrations were measured at 6 sites in each of 3 streams with high percentages of row crop land uses during high summer baseflow following the 1993 floods and during average summer baseflow in 1995. Nitrate concentrations were systematically higher for the high baseflow conditions of 1993 than the average year (1995). This change in nitrate concentration is interpreted as the increased effectiveness of nitrate delivery to the stream during periods of high water tables. The effect was most pronounced in incised reaches. All 3 streams show downstream decreases in nitrate concentration. Water samples for all the sites in the watersheds were analyzed for nitrogen isotopic composition. The nitrogen isotopic composition shifts with towards higher d 15N values with decreasing nitrate concentration. This is consistent with denitrification reactions that selectively remove the 14N leaving a higher proportion of 15N in the nitrate. This suggests that most of the downstream decrease in nitrate concentrations is a result of in-stream denitrification. The high rates

  12. Watershed basin management and agriculture practices: an application case for flooding areas in Piemonte.

    NASA Astrophysics Data System (ADS)

    Bianco, G.; Franzi, L.; Valvassore, U.

    2009-04-01

    Watershed basin management in Piemonte (Italy) is a challenging issue that forces the local Authorities to a careful land planning in the frame of a sustainable economy. Different and contrasting objectives should be taken into account and balanced in order to find the best or the most "reasonable" choice under many constraints. Frequently the need for flood risk reduction and the demand for economical exploitation of floodplain areas represent the most conflicting aspects that influence watershed management politics. Actually, flood plains have been the preferred places for socio-economical activities, due to the availability of water, fertility of soil and the easiness of agricultural soil exploitation. Sometimes the bed and planform profile adjustments of a river, as a consequence of natural processes, can impede some anthropogenic activities in agriculture, such as the erosion of areas used for crops, the impossibility of water diversion, the deposition of pollutants on the ground, with effects on the economy and on the social life of local communities. In these cases watershed basin management should either balance the opposite demands, as the protection of economic activities (that implies generally canalized rivers and levees construction) and the need of favouring the river morphological stability, allowing the flooding in the inundation areas. In the paper a case study in Piemonte region (Tortona irrigation district) is shown and discussed. The effects of the Scrivia river planform adjustment on water diversion and soil erodibility force the local community and the authority of the irrigation district to ask for flood protection and river bed excavation. A mathematical model is also applied to study the effects of local river channel excavation on flood risk. Some countermeasures are also suggested to properly balance the opposite needs in the frame of a watershed basin management.

  13. The distribution and modeling of nitrate transport in the Carson Valley alluvial aquifer, Douglas County, Nevada

    USGS Publications Warehouse

    Naranjo, Ramon C.; Welborn, Toby L.; Rosen, Michael R.

    2013-01-01

    The distribution of nitrate as nitrogen (referred to herein as nitrate-N) concentrations in groundwater was determined by collecting more than 200 samples from 8 land-use categories: single family residential, multifamily residential, rural (including land use for agriculture), vacant land, commercial, industrial, utilities, and unclassified. Nitrate-N concentrations ranged from below detection (less than 0.05 milligrams per liter) to 18 milligrams per liter. The results of nitrate-N concentrations that were sampled from three wells equalled or exceeded the maximum contaminant level of 10 milligrams per liter set by the U.S. Environmental Protection Agency. Nitrate-N concentrations in sampled wells showed a positive correlation between elevated nitrate-N concentrations and the percentage of single-family land use and septic-system density. Wells sampled in other land-use categories did not have any correlation to nitrate-N concentrations. In areas with greater than 50-percent single-family land use, nitrate-N concentrations were two times greater than in areas with less than 50 percent single-family land use. Nitrate-N concentrations in groundwater near septic systems that had been used more than 20 years were more than two times greater than in areas where septic systems had been used less than 20 years. Lower nitrate-N concentrations in the areas where septic systems were less than 20 years old probably result from temporary storage of nitrogen leaching from septic systems into the unsaturated zone. In areas where septic systems are abundant, nitrate-N concentrations were predicted to 2059 by using numerical models within the Ruhenstroth and Johnson Lane subdivisions in the Carson Valley. Model results indicated that nitrate-N concentrations will continue to increase and could exceed the maximum contaminant level over extended areas inside and outside the subdivisions. Two modeling scenarios were used to simulate future transport as a result of removal of septic

  14. Accumulation of nitrogen and changes in assimilation pigments of lichens transplanted in an agricultural area.

    PubMed

    Frati, Luisa; Brunialti, Giorgio; Gaudino, Stefania; Pati, Alessandra; Rosamilia, Silvia; Loppi, Stefano

    2011-07-01

    The results of a survey aimed at testing the hypothesis that the lichen Evernia prunastri, when transplanted in an agricultural area with high atmospheric NH(3) concentrations, would respond to NH(3) air pollution accumulating nitrogen in its thalli and showing changes in the concentration of assimilation pigments are presented. The results confirmed the hypothesis and showed that all lichen transplants accumulated nitrogen, suggesting that besides the release of atmospheric ammonia by animal stockfarms, the use of N-based fertilizers and the deposition of N-rich dust also may contribute to the high nitrogen availability to lichens in the study area. The result indicated that in the study area both the critical level of NH(3) and the critical load of N for lichens are exceeded and physiological damage is to be expected in sensitive species. The results of assimilation pigments in E. prunastri, with a decrease in the concentration of chlorophylls a and b and carotenoids, as well as chlorophyll degradation to phaeophytin, confirmed this hypothesis. However, owing to the limited data set and pending further studies, these conclusions should be considered as limited to the study area.

  15. The impact of stormwater treatment areas and agricultural best management practices on water quality in the Everglades Protection Area.

    PubMed

    Entry, James A; Gottlieb, Andrew

    2014-02-01

    Half of the original Everglades system has been lost to drainage and development. What remains is included within the boundaries of the Everglades Protection Area (EPA), comprised of three Water Conservation Areas (WCAs) and Everglades National Park (Park). Inflows to the EPA contain elevated nutrient concentrations. Best management practices (BMPs) were implemented and six large wetlands called stormwater treatment areas (STAs) were constructed to improve water quality. We analyzed water quality in the WCAs and Park and performed an economic analysis of the STAs to remove nutrients from EPA inflows. In general, nutrient concentrations in all WCAs were higher during the pre-STA period than after the STAs became operational. In WCA2 and the Park, total phosphorus (TP) trends showed more negative slopes prior, as compared to after, the STAs became operational. These results suggest that BMPs lead to large initial decreases in nutrient export resulting in improved downstream water quality. A preliminary economic analysis shows that operation and management of the STAs are complicated and cost intensive. Comparing the cost of phosphorus (P) removal from water entering the EPA using BMPs and STAs may not currently be viable. BMPs prevent P from being applied to, or leaving from agricultural fields while STAs remove P from stormwater. We expect nutrient concentrations in water flowing into and out of the STAs to decline as both BMPs and STAs become more effective. We suggest an economic analysis of BMPs, STAs, and other potential approaches to determine the most cost-effective methods to reduce nutrient concentrations and related stressors affecting the Everglades.

  16. Integrated assessment on groundwater nitrate by unsaturated zone probing and aquifer sampling with environmental tracers.

    PubMed

    Yuan, Lijuan; Pang, Zhonghe; Huang, Tianming

    2012-12-01

    By employing chemical and isotopic tracers ((15)N and (18)O in NO(3)(-)), we investigated the main processes controlling nitrate distribution in the unsaturated zone and aquifer. Soil water was extracted from two soil cores drilled in a typical agricultural cropping area of the North China Plain (NCP), where groundwater was also sampled. The results indicate that evaporation and denitrification are the two major causes of the distribution of nitrate in soil water extracts in the unsaturated zone. Evaporation from unsaturated zone is evidenced by a positive correlation between chloride and nitrate, and denitrification by a strong linear relationship between [Formula: see text] and ln(NO(3)(-)/Cl). The latter is estimated to account for up to 50% of the nitrate loss from soil drainage. In the saturated zone, nitrate is reduced at varying extents (100 mg/L and 10 mg/L at two sites, respectively), largely by dilution of the aquifer water.

  17. Nitrogen-isotope ratios of nitrate in ground water under fertilized fields, Long Island, New York

    USGS Publications Warehouse

    Flipse, W.J.; Bonner, F.T.

    1985-01-01

    Ground-water samples from two heavily fertilized sites in Suffolk County, New York, were collected through the 1978 growing season and analyzed for nitrate-N concentrations and nitrogen-isotope ratios. Six wells were at a potato farm; six were on a golf course. The purpose of this study was to determine whether the 15N/14N ratios (??15N values) of fertilizer are increased during transit from land surface to ground water to an extent which would preclude use of this ratio to distinguish agricultural from animal sources of nitrate in ground water. Ground water at both sites contained a greater proportion of 15N than the fertilizers being applied. At the potato farm, the average ??15N value of the fertilizers was 0.2???; the average ??15N value of the ground-water nitrate was 6.2???. At the golf course, the average ??15N value of the fertilizers was -5.9???, and that of ground-water nitrate was 6.5???. The higher ??15N values of ground-water nitrate are probably caused by isotopic fractionation during the volatile loss of ammonia from nitrogen applied in reduced forms (NH4+ and organic-N). The ??15N values of most ground-water samples from both areas were less than 10???, the upper limit of the range characteristic of agricultural sources of nitrate; these sources include both fertilizer nitrate and nitrate derived from increased mineralization of soil nitrogen through cultivation. Previous studies have shown that the ??15N values of nitrate derived from human or animal waste generally exceed 10???. The nitrogen-isotope ratios of fertilizer-derived nitrate were not altered to an extent that would make them indistinguishable from animal-waste-derived nitrates in ground water.Ground-water samples from two heavily fertilized sites in Suffolk County, New York, were collected through the 1978 growing season and analyzed for nitrate-N concentrations and nitrogen-isotope ratios. Six wells were at a potato farm; six were on a golf course. The purpose of this study was to

  18. Nitrogen export from an agriculture watershed in the Taihu Lake area, China.

    PubMed

    Gao, C; Zhu, J G; Zhu, J Y; Gao, X; Dou, Y J; Hosen, Y

    2004-01-01

    Temporal changes in nitrogen concentrations and stream discharge, as well as sediment and nitrogen losses from erosion plots with different land uses, were studied in an agricultural watershed in the Taihu Lake area in eastern China. The highest overland runoff loads and nitrogen losses were measured under the upland at a convergent footslope. Much higher runoff, sediment and nitrogen losses were observed under upland cropping and vegetable fields than that under chestnut orchard and bamboo forest. Sediment associated nitrogen losses accounted for 8-43.5% of total nitrogen export via overland runoff. N lost in dissolved inorganic nitrogen forms (NO(3-)-N + NH4+-N) accounted for less than 50% of total water associated nitrogen export. Agricultural practices and weather-driven fluctuation in discharge were main reasons for the temporal variations in nutrient losses via stream discharge. Significant correlation between the total nitrogen concentration and stream discharge load was observed. Simple regression models could give satisfactory results for prediction of the total nitrogen concentrations in stream water and can be used for better quantifying nitrogen losses from arable land. Nitrogen losses from the studied watershed via stream discharge during rice season in the year 2002 were estimated to be 10.5 kg N/ha using these simple models.

  19. The Red Blood Cell Acetylcholinesterase Levels of Depressive Patients with Suicidal Behavior in an Agricultural Area.

    PubMed

    Altinyazar, Vesile; Sirin, Fevziye Burcu; Sutcu, Recep; Eren, Ibrahim; Omurlu, Imran Kurt

    2016-10-01

    Long-term exposure to organophosphate pesticides (OPs) without acute poisoning can lead to various OPs. Environmental exposure to organophosphate pesticides may be associated with depression and suicide attempts in a population living in a rural agricultural area. Patients (n = 149) suffering from major depressive disorder (with and without attempted suicide) and a control group of healthy individuals (n = 64) who had been living in the same rural district for at least 1 year were selected. Red blood cell acetylcholine esterase (RBC-AChE) activity was examined as the basis of evaluating the degree of chronic environmental exposure to OPs residues. There were negative association between RBC-AChE activity levels and suicide attempts, the number of past suicide attempts and hopelessness levels in the depressive patients. The results of the study may support the idea that environmental exposure to OPs may be associated with mental health in individuals living in agricultural districts who are not farmers or working in occupations with access to OPs. PMID:27605747

  20. Groundwater vulnerability assessment in agricultural areas using a modified DRASTIC model.

    PubMed

    Sadat-Noori, Mahmood; Ebrahimi, Kumars

    2016-01-01

    Groundwater contamination is a major concern for groundwater resource managers worldwide. We evaluated groundwater pollution potential by producing a vulnerability map of an aquifer using a modified Depth to water, Net recharge, Aquifer media, Soil media, Topography, Impact of vadose zone, and Hydraulic conductivity (DRASTIC) model within a Geographic Information System (GIS) environment. The proposed modification which incorporated the use of statistical techniques optimizes the rating function of the DRASTIC model parameters, to obtain a more accurate vulnerability map. The new rates were computed using the relationships between the parameters and point data chloride concentrations in groundwater. The model was applied on Saveh-Nobaran plain in central Iran, and results showed that the coefficient of determination (R (2)) between the point data and the relevant vulnerability map increased significantly from 0.52 to 0.78 after modification. As compared to the original DRASTIC model, the modified version produced better vulnerability zonation. Additionally, single-parameter and parameter removal sensitivity analyses were performed to evaluate the relative importance of each DRASTIC parameter. The results from both analyses revealed that the vadose zone is the most sensitive parameter influencing the variability of the aquifers' vulnerability index. Based on the results, for non-point source pollution in agricultural areas, using the modified DRASTIC model is efficient compared to the original model. The proposed method can be effective for future groundwater assessment and plain-land management where agricultural activities are dominant. PMID:26650205

  1. Groundwater vulnerability assessment in agricultural areas using a modified DRASTIC model.

    PubMed

    Sadat-Noori, Mahmood; Ebrahimi, Kumars

    2016-01-01

    Groundwater contamination is a major concern for groundwater resource managers worldwide. We evaluated groundwater pollution potential by producing a vulnerability map of an aquifer using a modified Depth to water, Net recharge, Aquifer media, Soil media, Topography, Impact of vadose zone, and Hydraulic conductivity (DRASTIC) model within a Geographic Information System (GIS) environment. The proposed modification which incorporated the use of statistical techniques optimizes the rating function of the DRASTIC model parameters, to obtain a more accurate vulnerability map. The new rates were computed using the relationships between the parameters and point data chloride concentrations in groundwater. The model was applied on Saveh-Nobaran plain in central Iran, and results showed that the coefficient of determination (R (2)) between the point data and the relevant vulnerability map increased significantly from 0.52 to 0.78 after modification. As compared to the original DRASTIC model, the modified version produced better vulnerability zonation. Additionally, single-parameter and parameter removal sensitivity analyses were performed to evaluate the relative importance of each DRASTIC parameter. The results from both analyses revealed that the vadose zone is the most sensitive parameter influencing the variability of the aquifers' vulnerability index. Based on the results, for non-point source pollution in agricultural areas, using the modified DRASTIC model is efficient compared to the original model. The proposed method can be effective for future groundwater assessment and plain-land management where agricultural activities are dominant.

  2. Habitat characteristics of benchmark streams in agricultural areas of eastern Wisconsin

    USGS Publications Warehouse

    Fitzpatrick, F.A.; Peterson, E.M.; Stewart, J.S.

    1996-01-01

    Stream habitat characteristics were measured at twenty sites in agricultural areas of eastern Wisconsin by the U.S. Geological Survey in May and June, 1993 as part of the National Water-Quality Assessment Program Western Lake Michigan Drainages study unit. These "benchmark" stream sites were selected for study to represent standards of reference for comparison to other streams in similar physical settings that appear to be more detrimentally affected by agriculture. The agricultural benchmark streams were selected from four physical settings, or relatively homogeneous units (RHU's), that differ in bedrock type and texture of surficial deposits. Habitat characteristics at streams in these four physical settings are described and compared to each other, and a habitat classification scheme was used to rank the quality of habitat in these streams. Additional aquatic information was collected along with the habitat data: water-quality data and population surveys of fish, invertebrates, and algae. Habitat data were collected at three levels: drainage basin, stream segment between major tributaries (length from 1 to 14 km), and stream reach (approximately 150m). Results of statistical analyses show that, in general, most correlations are among basin-level habitat characteristics. Few correlations were observed among reach- and basin-level characteristics. Principal components analysis (PCA) on basin-level data resulted in principal components that reflect RHU, land use or latitude, and basin size. Groupings of habitat characteristics at the reach level are less clearly attributed to some outside environmental factor. Streams that have undergone habitat restoration for fisheries group closely together on PCA ordination plots. Less than half of the habitat characteristics were found to be significantly different between one RHU and the other three. Characteristics that differed between RHU's were mainly at the basin level but also included some reach-level characteristics

  3. Fate of phthalates and BPA in agricultural and non-agricultural soils of the Paris area (France).

    PubMed

    Tran, Bich Chau; Teil, Marie-Jeanne; Blanchard, Martine; Alliot, Fabrice; Chevreuil, Marc

    2015-07-01

    This study (i) investigated the concentration levels of nine phthalates and bisphenol A (BPA) in sludge samples originating from a French wastewater treatment plant (WWTP), (ii) studied the distribution of target compounds according to soil depth and calculated their half-lives, and (iii) compared the contamination level of the agricultural soil with those of soils with other land uses. The sludge contamination levels varied from a few hundred nanograms per gram dry weight (dw) for diethyl phthalate (DEP), di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and butyl-benzyl phthalate (BBP) to a few micrograms per gram dw for diethylhexyl phthalate (DEHP), di-iso-nonyl phthalate (DiNP), and di-iso-decyl phthalate (DiDP). After sludge application, an 8-fold increase for DEHP level and a 3-fold increase for BPA level occurred in the surface horizon of the soil. The mean distribution of phthalates according to the depth showed a positive gradient for the low molecular weight compounds and inversely, a negative gradient for the highest ones. The half-lives in the 0-20-cm soil horizon were 64 days for DEHP and 36 days for BPA. A predictive environmental concentration (PEC) of 0.3 μg g(-1) dw was estimated for DEHP, while the experimental value was 0.16 μg g(-1) dw, suggesting degradation processes in soil and/or formation of non-extractable residues. Comparisons of contamination levels for soils from different origins (urban, rural, agricultural, and forest) showed that the urban soil remained the most contaminated one, prior to the agricultural soil after treatment.

  4. Fate of phthalates and BPA in agricultural and non-agricultural soils of the Paris area (France).

    PubMed

    Tran, Bich Chau; Teil, Marie-Jeanne; Blanchard, Martine; Alliot, Fabrice; Chevreuil, Marc

    2015-07-01

    This study (i) investigated the concentration levels of nine phthalates and bisphenol A (BPA) in sludge samples originating from a French wastewater treatment plant (WWTP), (ii) studied the distribution of target compounds according to soil depth and calculated their half-lives, and (iii) compared the contamination level of the agricultural soil with those of soils with other land uses. The sludge contamination levels varied from a few hundred nanograms per gram dry weight (dw) for diethyl phthalate (DEP), di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and butyl-benzyl phthalate (BBP) to a few micrograms per gram dw for diethylhexyl phthalate (DEHP), di-iso-nonyl phthalate (DiNP), and di-iso-decyl phthalate (DiDP). After sludge application, an 8-fold increase for DEHP level and a 3-fold increase for BPA level occurred in the surface horizon of the soil. The mean distribution of phthalates according to the depth showed a positive gradient for the low molecular weight compounds and inversely, a negative gradient for the highest ones. The half-lives in the 0-20-cm soil horizon were 64 days for DEHP and 36 days for BPA. A predictive environmental concentration (PEC) of 0.3 μg g(-1) dw was estimated for DEHP, while the experimental value was 0.16 μg g(-1) dw, suggesting degradation processes in soil and/or formation of non-extractable residues. Comparisons of contamination levels for soils from different origins (urban, rural, agricultural, and forest) showed that the urban soil remained the most contaminated one, prior to the agricultural soil after treatment. PMID:25794574

  5. Risk of nitrate in groundwaters of the United States - A national perspective

    USGS Publications Warehouse

    Nolan, B.T.; Ruddy, B.C.; Hitt, K.J.; Helsel, D.R.

    1997-01-01

    Nitrate contamination of groundwater occurs in predictable patterns, based on findings of the U.S. Geological Survey's (USGS) National Water Quality Assessment (NAWQA) Program. The NAWQA Program was begun in 1991 to describe the quality of the Nation's water resources, using nationally consistent methods. Variables affecting nitrate concentration in groundwater were grouped as 'input' factors (population density end the amount of nitrogen contributed by fertilizer, manure, and atmospheric sources) and 'aquifer vulnerability' factors (soil drainage characteristic and the ratio of woodland acres to cropland acres in agricultural areas) and compiled in a national map that shows patterns of risk for nitrate contamination of groundwater. Areas with high nitrogen input, well-drained soils, and low woodland to cropland ratio have the highest potential for contamination of shallow groundwater by nitrate. Groundwater nitrate data collected through 1992 from wells less than 100 ft deep generally verified the risk patterns shown on the national map. Median nitrate concentration was 0.2 mg/L in wells representing the low-risk group, and the maximum contaminant level (MCL) was exceeded in 3% of the wells. In contrast, median nitrate concentration was 4.8 mg/L in wells representing the high-risk group, and the MCL was exceeded in 25% of the wells.Nitrate contamination of groundwater occurs in predictable patterns, based on findings of the U.S. Geological Survey's (USGS) National Water Quality Assessment (NAWQA) Program. The NAWQA Program was begun in 1991 to describe the quality of the Nation's water resources, using nationally consistent methods. Variables affecting nitrate concentration in groundwater were grouped as `input' factors (population density and the amount of nitrogen contributed by fertilizer, manure, and atmospheric sources) and `aquifer vulnerability' factors (soil drainage characteristic and the ratio of woodland acres to cropland acres in agricultural areas

  6. Agricultural recovery of a formerly contaminated area: Establishment of a high-resolution quantitative protein map of mature flax seeds harvested from the remediated chernobyl area

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years there has been an increasing tendency toward remediation of contaminated areas for agricultural purposes. The study described herein is part of a comprehensive, long-term characterization of crop plants grown in the area formerly contaminated with radioactivity. As a first step, we ...

  7. Molecular detection of Pythium insidiosum from soil in Thai agricultural areas.

    PubMed

    Vanittanakom, Nongnuch; Szekely, Jidapa; Khanthawong, Sophit; Sawutdeechaikul, Pritsana; Vanittanakom, Pramote; Fisher, Matthew C

    2014-05-01

    Pythium insidiosum is an aquatic fungus-like organism in the kingdom Stramenopila that causes pythiosis in both humans and animals. Human pythiosis occurs in ocular, localized granulomatous subcutaneous and systemic or vascular forms. Individuals whose occupations involve exposure to aquatic habitats have an elevated risk of contracting pythiosis. Previously, we reported the first successful isolation of Pythium insidiosum from aquatic environmental samples by culture including confirmation using molecular methods. In this study, we show that P. insidiosum inhabitats moist soil environments in agricultural areas. A total of 303 soil samples were collected from 25 irrigation sources in the areas nearby the recorded home addresses of pythiosis patients residing in northern provinces of Thailand. P. insidiosum DNA was identified directly from each soil extract by using a nested PCR assay and subsequent phylogenetic analysis of the ribosomal intragenic spacer region. P. insidiosum DNA could be detected from 16 of the 25 soil sources (64%). Conventional culture methods were also performed, however all samples exhibited negative culture results. We conclude that both irrigation water and soil are the natural reservoirs of P. insidiosum. In endemic areas, the exposure to these environmental reservoirs should be considered a risk factor for hosts susceptible to pythiosis. PMID:24444720

  8. Molecular detection of Pythium insidiosum from soil in Thai agricultural areas.

    PubMed

    Vanittanakom, Nongnuch; Szekely, Jidapa; Khanthawong, Sophit; Sawutdeechaikul, Pritsana; Vanittanakom, Pramote; Fisher, Matthew C

    2014-05-01

    Pythium insidiosum is an aquatic fungus-like organism in the kingdom Stramenopila that causes pythiosis in both humans and animals. Human pythiosis occurs in ocular, localized granulomatous subcutaneous and systemic or vascular forms. Individuals whose occupations involve exposure to aquatic habitats have an elevated risk of contracting pythiosis. Previously, we reported the first successful isolation of Pythium insidiosum from aquatic environmental samples by culture including confirmation using molecular methods. In this study, we show that P. insidiosum inhabitats moist soil environments in agricultural areas. A total of 303 soil samples were collected from 25 irrigation sources in the areas nearby the recorded home addresses of pythiosis patients residing in northern provinces of Thailand. P. insidiosum DNA was identified directly from each soil extract by using a nested PCR assay and subsequent phylogenetic analysis of the ribosomal intragenic spacer region. P. insidiosum DNA could be detected from 16 of the 25 soil sources (64%). Conventional culture methods were also performed, however all samples exhibited negative culture results. We conclude that both irrigation water and soil are the natural reservoirs of P. insidiosum. In endemic areas, the exposure to these environmental reservoirs should be considered a risk factor for hosts susceptible to pythiosis.

  9. Potential use of Solanum melongena in agricultural areas with high mercury background concentrations.

    PubMed

    Sierra, M J; Millán, R; Esteban, E

    2008-06-01

    Solanum melongena L. (eggplant) is a native culture from India, found throughout the world, and is one of the most popular vegetables in the Mediterranean area. This work evaluates the potential use of eggplant as an economic alternative in an area with high mercury background concentrations. This implies the study of several factors such as the mercury absorption capacity of eggplant and the capacity of the soil for agricultural use. The research work has been carried out using soil from the mercury mining district of Almadén (Spain), where total mercury concentration was on average 14.16+/-0.65mgkg(-1). In this area, eggplant is a typical crop that is widely used for human consumption. The experimental work was performed in pots under greenhouse conditions. Three samplings were performed during the entire cultivation cycle. Mercury concentration was determined in the different plant organs, where the highest concentration was located in the root system. The results obtained show that the consumption of eggplant, growing under these controlled conditions, does not suppose a risk for human health according to the recommendations of the World Health Organization.

  10. Occurrence of nitrate in Tanzanian groundwater aquifers: A review

    NASA Astrophysics Data System (ADS)

    Elisante, Eliapenda; Muzuka, Alfred N. N.

    2015-03-01

    More than 25 % of Tanzanian depends on groundwater as the main source of water for drinking, irrigation and industrial activities. The current trend of land use may lead to groundwater contamination and thus increasing risks associated with the usage of contaminated water. Nitrate is one of the contaminants resulting largely from anthropogenic activities that may find its way to the aquifers and thus threatening the quality of groundwater. Elevated levels of nitrate in groundwater may lead to human health and environmental problems. The current trend of land use in Tanzania associated with high population growth, poor sanitation facilities and fertilizer usage may lead to nitrate contamination of groundwater. This paper therefore aimed at providing an overview of to what extent human activities have altered the concentration of nitrate in groundwater aquifers in Tanzania. The concentration of nitrate in Tanzanian groundwater is variable with highest values observable in Dar es Salaam (up to 477.6 mg/l), Dodoma (up to 441.1 mg/l), Tanga (above 100 mg/l) and Manyara (180 mg/l). Such high values can be attributed to various human activities including onsite sanitation in urban centres and agricultural activities in rural areas. Furthermore, there are some signs of increasing concentration of nitrate in groundwater with time in some areas in response to increased human activities. However, reports on levels and trends of nitrate in groundwater in many regions of the country are lacking. For Tanzania to appropriately address the issue of groundwater contamination, a deliberate move to determine nitrate concentration in groundwater is required, as well as protection of recharge basins and improvement of onsite sanitation systems.

  11. Bayesian nitrate source apportionment to individual groundwater wells in the Central Valley by use of elemental and isotopic tracers

    NASA Astrophysics Data System (ADS)

    Ransom, Katherine M.; Grote, Mark N.; Deinhart, Amanda; Eppich, Gary; Kendall, Carol; Sanborn, Matthew E.; Souders, A. Kate; Wimpenny, Joshua; Yin, Qing-zhu; Young, Megan; Harter, Thomas

    2016-07-01

    Groundwater quality is a concern in alluvial aquifers that underlie agricultural areas, such as in the San Joaquin Valley of California. Shallow domestic wells (less than 150 m deep) in agricultural areas are often contaminated by nitrate. Agricultural and rural nitrate sources include dairy manure, synthetic fertilizers, and septic waste. Knowledge of the relative proportion that each of these sources contributes to nitrate concentration in individual wells can aid future regulatory and land management decisions. We show that nitrogen and oxygen isotopes of nitrate, boron isotopes, and iodine concentrations are a useful, novel combination of groundwater tracers to differentiate between manure, fertilizers, septic waste, and natural sources of nitrate. Furthermore, in this work, we develop a new Bayesian mixing model in which these isotopic and elemental tracers were used to estimate the probability distribution of the fractional contributions of manure, fertilizers, septic waste, and natural sources to the nitrate concentration found in an individual well. The approach was applied to 56 nitrate-impacted private domestic wells located in the San Joaquin Valley. Model analysis found that some domestic wells were clearly dominated by the manure source and suggests evidence for majority contributions from either the septic or fertilizer source for other wells. But, predictions of fractional contributions for septic and fertilizer sources were often of similar magnitude, perhaps because modeled uncertainty about the fraction of each was large. For validation of the Bayesian model, fractional estimates were compared to surrounding land use and estimated source contributions were broadly consistent with nearby land use types.

  12. Fish communities of benchmark streams in agricultural areas of eastern Wisconsin

    USGS Publications Warehouse

    Sullivan, D.J.; Peterson, E.M.

    1997-01-01

    Fish communities were surveyed at 20 stream sites in agricultural areas in eastern Wisconsin in 1993 and 1995 as part of the National Water-Quality Assessment (NAWQA) Program. These streams, designated "benchmark streams," were selected for study because of their potential use as regional references for healthy streams in agricultural areas, based on aquatic communities, habitat, and water chemistry. The agricultural benchmark streams were selected from four physical settings, or relatively homogeneous units (RHU's), that differ in bedrock type, texture of surficial deposits, and land use. Additional data were collected along with the fish-community data, including measures of habitat, water chemistry, and population surveys of algae and benthic invertebrates. Of the 20 sites, 19 are classified as trout (salmonid) streams. Fish species that require cold or cool water were the most commonly collected. At least one species of trout was collected at 18 sites, and trout were the most abundant species at 13 sites. The species with the greatest collective abundance, and collected at 18 of the 20 sites, were mottled sculpin (Cottus bairdi), a coldwater species. The next most abundant species were brown trout (Salmo trutta), followed by brook trout (Salvelinusfontinalis), creek chub (Semotilus atromaculatus), and longnose dace (Rhinichthys cataractae). In all, 31 species of fish were collected. The number of species per stream ranged from 2 to 14, and the number of individuals collected ranged from 19 to 264. According to Index of Biotic Integrity (IBI) scores, 5 sites were rated excellent, 10 sites rated good, 4 rated fair, and 1 rated poor. The ratings of the five sites in the fair to poor range were low for various reasons. Two sites appeared to have more warmwater species than was ideal for a high-quality coldwater stream. One was sampled during high flow and the results may not be valid for periods of normal flow; the other may have been populated by migrating

  13. Flow and geochemistry along shallow ground-water flowpaths in an agricultural area in southeastern Wisconsin

    USGS Publications Warehouse

    Saad, D.A.; Thorstenson, D.C.

    1998-01-01

    Ground water recharging at mid- and downgradient wells is oxic and contains dissolved nitrate, whereas the ground water discharging to the stream is anoxic and contains dissolved ammonium. Redox environments were defined at each well on the basis of relative concentrations of various dissolved redox-active species. Chemically permissible flowpaths inferred from the observed sequence of redox environments at well sites are consistent with flowpaths in the ground-water flow model. The transition from nitrate in recharging ground water to ammonium in ground water discharging to the stream suggests the possibility of nitrate reduction along the flowpath. None of the techniques employed in this study, however, were able to prove the occurrence of this reaction.

  14. Assessing the impact of pluriactivity on sustainable agriculture. A case study in rural areas of Beotia in Greece.

    PubMed

    Giourga, Christina; Loumou, Angeliki

    2006-06-01

    Pluriactivity of farms, or part-time farming, is a common feature of agriculture in all countries regardless of their socioeconomic system and level of development. Currently, pluriactivity is related to the values of sustainable agriculture. The objective of this study is to delineate those specific characteristics of pluriactive farms that contribute to sustainable agriculture. In rural areas of Boetia in Greece, a socioeconomic survey was carried out on 114 farms to determine the types of farming applied. The results demonstrate that pluriactivity is a stable component of the agricultural structure in the rural areas of Boetia. It is widespread in plains, but its presence is more important in mountainous and semimountainous areas. The choice of young farmers is to opt for pluriactivity. Farm size does not differ between pluriactive and full-time farms. Pluriactive and full- time farms use the same level of input and get the same output for the same type of crop. However, pluriactive farmers under the same land-productive conditions are oriented toward a more extensive farming system, managing their land with crops that need less inputs. Considering these findings, it can be claimed that pluriactivity can contribute to diminishing the demand on natural resources in favored (level and irrigated) areas, to continue agricultural production in unfavorable (mountainous and semimountainous) areas, and to help the sustenance of the rural population.

  15. [Distribution Characteristics and Influencing Factors of Nitrate Pollution in Shallow Groundwater of Liujiang Basin].

    PubMed

    Wang, He; Gu, Hong-biao; Chi, Bao-ming; Li, Hai-jun; Jiang, Hai-ning

    2016-05-15

    Taking the nitrate in shallow groundwater of Liujiang basin as the research object, a total of 215 groups of shallow groundwater samples were collected during the wet period in July 2014 and the drought period in April 2015 on the basis of groundwater pollution investigation. The characteristics of spatial and temporal variability and the account of nitrate pollution were analyzed based on the model of semivariogram, the geostatistics of ArcGIS and factor analysis, respectively. The results showed that the study region in the southeast was the main nitrate-polluted area, with concentrations of up to 30-120 mg · L⁻¹, in both wet and drought periods, while the nitrate-contaminated area in drought period was about 1. 4 times higher than that in wet period. The spatial distribution of nitrate was primarily influenced by human activities and the geological conditions, and secondarily by Eh, DO, pH and landform conditions. The nitrate concentration was less than 20 mg · L⁻¹ in north. Pollution in local middle area was rather serious, due to human activities and the loss of nitrogen fertilizer in agricultural cultivation; the area to the south, which was confined by impervious boundary, was seriously contaminated, as indicated by the nitrate accumulation effects.

  16. [Distribution Characteristics and Influencing Factors of Nitrate Pollution in Shallow Groundwater of Liujiang Basin].

    PubMed

    Wang, He; Gu, Hong-biao; Chi, Bao-ming; Li, Hai-jun; Jiang, Hai-ning

    2016-05-15

    Taking the nitrate in shallow groundwater of Liujiang basin as the research object, a total of 215 groups of shallow groundwater samples were collected during the wet period in July 2014 and the drought period in April 2015 on the basis of groundwater pollution investigation. The characteristics of spatial and temporal variability and the account of nitrate pollution were analyzed based on the model of semivariogram, the geostatistics of ArcGIS and factor analysis, respectively. The results showed that the study region in the southeast was the main nitrate-polluted area, with concentrations of up to 30-120 mg · L⁻¹, in both wet and drought periods, while the nitrate-contaminated area in drought period was about 1. 4 times higher than that in wet period. The spatial distribution of nitrate was primarily influenced by human activities and the geological conditions, and secondarily by Eh, DO, pH and landform conditions. The nitrate concentration was less than 20 mg · L⁻¹ in north. Pollution in local middle area was rather serious, due to human activities and the loss of nitrogen fertilizer in agricultural cultivation; the area to the south, which was confined by impervious boundary, was seriously contaminated, as indicated by the nitrate accumulation effects. PMID:27506022

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  18. InSAR deformation time series for an agricultural area in the San Luis Valley

    NASA Astrophysics Data System (ADS)

    Reeves, J. A.; Knight, R.; Zebker, H. A.; Schreüder, W. A.; Shanker, P.; Lauknes, T. R.

    2009-05-01

    The San Luis Valley (SLV) is an 8000 km2 region in southern Colorado that is home to a thriving agricultural economy. This valley is currently in a period of extreme drought, with county and state regulators struggling to develop appropriate management policies for both the surface water and the ground water. In 1998 the state of Colorado commissioned the Rio Grande Decision Support System to refine the hydogeologic characterization of the system, including the development of a MODFLOW finite difference model of groundwater flow. The main challenge in the SLV is acquiring sufficient data to characterize the spatially heterogeneous, time-varying behavior of the groundwater system. Here we apply the small baseline subset analysis (SBAS) interferometric radar (InSAR) technique to provide such data. InSAR techniques yield the deformation of Earth's surface at fine spatial resolution occurring between two satellite overflights, and SBAS permits solution for a time series of deformation maps. The measured deformation can be related to changes in the water table in underlying confined aquifers. The ability to map these changes, over time, in the SLV will provide critical information about the groundwater system. Historically, InSAR measurements have been difficult to make in agricultural areas. The change in cm-scale crop structure with time leads to signal decorrelation and the loss of useful information about surface deformation. The recently-developed SBAS method allows stable deformation estimates at certain ground points in an otherwise decorrelated time series of data. We applied this approach to data collected by the European Space Agency's ERS-1 and ERS-2 satellites over the western SLV from track 98 frame 2853 for the years 1992-2001. We used the Generic SAR (GSAR) SBAS software developed by Norut to produce time series deformation measurements for many positions across the entire SLV. We find that the 2000 km2 area captured in track 98 frame 2853 shows very high

  19. Nitrate Contamination of Shallow Groundwater in The San Joaquin Valley - A Domestic Well Survey

    NASA Astrophysics Data System (ADS)

    Lockhart, K.; King, A.

    2011-12-01

    Groundwater quality has been, and continues to be, a major concern in agricultural areas where concentrated animal feeding operations (CAFO) exist or where fertilizers are applied. In the San Joaquin Valley, California, the majority of land-use is agricultural and groundwater contamination by nitrate is common in areas where many people rely on shallow domestic wells. Elevated levels of nitrate in drinking water have been linked to adverse health effects. This project sampled 200 domestic wells in Stanislaus, Merced, Tulare, and Kings Counties for nitrate as NO3-N. Wells were given a "dairy" or "non-dairy" designation depending on the distance to the nearest dairy corral or lagoon. This study found 46% of wells sampled in Tulare and Kings Counties and 42% of wells sampled in Stanislaus and Merced Counties exceeded the MCL for nitrate (10 mg/l). In Tulare and Kings Counties, non-dairy wells had a significantly greater mean nitrate value than dairy wells, and Tulare and Kings County non-dairy wells had a significantly greater mean nitrate value than Stanislaus and Merced non-dairy wells. Stanislaus and Merced County dairy wells had a significantly greater mean nitrate value than Tulare and Kings dairy wells. Tulare and Kings non-dairy wells may have greater nitrate values due to overlying row-crop and orchard land-use (commonly citrus) and the large quantities of fertilizers typically applied to these crops. Stanislaus and Merced Counties contain some of the densest CAFO areas of the state, possibly leading to Stanislaus and Merced dairy wells having higher nitrate concentrations than Tulare and Kings dairy wells.

  20. Potential assessment of establishing a renewable energy plant in a rural agricultural area.

    PubMed

    Su, Ming-Chien; Kao, Nien-Hsin; Huang, Wen-Jar

    2012-06-01

    An evaluation of the green energy potential generated from biogas and solar power, using agricultural manure waste and a photovoltaic (PV) system, was conducted in a large geographical area of a rural county with low population density and low pollution. The studied area, Shoufeng Township in Hualien County, is located in eastern Taiwan, where a large amount of manure waste is generated from pig farms that are scattered throughout the county. The objective of the study is to assess the possibility of establishing an integrated manure waste treatment plant by using the generated biogas incorporated with the PV system to produce renewable energy and then feed it back to the incorporated farms. A filed investigation, geographic information system (GIS) application, empirical equations development, and RETScreen modeling were conducted in the study. The results indicate that Shoufeng Township has the highest priority in setting up an integrated treatment and renewable energy plant by using GIS mapping within a 10-km radius of the transportation range. Two scenarios were plotted in assessing the renewable energy plant and the estimated electricity generation, plus the greenhouse gas (GHG) reduction was evaluated. Under the current governmental green energy scheme and from a long-term perspective, the assessment shows great potential in establishing the plant, especially in reducing environmental pollution problems, waste treatment, and developing suitable renewable energy.

  1. Contributions of increased agricultural abandonment area to recent surface warming trend in Shikoku Island, Japan

    NASA Astrophysics Data System (ADS)

    Yoshida, R.; Nishimori, M.; Iizumi, T.; Osawa, T.

    2012-04-01

    surrounding sea (e.g. land and sea breeze), mitigating air temperature changes caused by land surface parameter change. We derived geographical distributions of parameter sensitivity on air temperatures with these processes. Temperature changes for 1985-2005 caused by cropland decreasing or abandoned cropland and building lots increasing were estimated based on parameter sensitivity to temperatures which were derived in previous calculation and cropland area data obtained from the Census for Agriculture, Forestry and Fisheries data set (Ministry of Agriculture, Forestry and Fisheries, Japan). Calculated temperature changes for 21-years using the sensitivity and the dataset were respectively 39.6, 46.0, and 27.5 % for the daily maximum, mean and minimum temperature to trends of 18-sites averaged observation stations in Shikoku Island, indicating significant impact of land surface change on air temperatures. An evaluation method we applied in this study first calculated land surface parameter sensitivities on air temperatures with three-dimensional atmospheric model and secondly calculated linear combination of products of each sensitivity and cropland change ratio. Although first calculation needs high calculation cost because it uses three-dimensional atmospheric model, second one has little cost if once sensitivities were derived. This method would enable us to make air temperature change scenario caused by various land use change scenario without high numerical calculation costs.

  2. MANPOWER NEEDS AND EMPLOYMENT OPPORTUNITIES FOR WORKERS NEEDING KNOWLEDGE AND SKILL IN AGRICULTURE. TECHNICAL EDUCATION IN AND FOR RURAL AREAS, REPORT NUMBER 2.

    ERIC Educational Resources Information Center

    WARMBROD, J. ROBERT

    THREE TYPES OF FIRMS IN A 14-COUNTY AREA WERE SURVEYED TO DETERMINE THE NUMBER OF WORKERS WITH AGRICULTURAL COMPETENCIES REQUIRED IN THE OFF-FARM AGRICULTURAL OCCUPATIONS AND TO COMPARE EMPLOYMENT OPPORTUNITIES IN FARM AND OFF-FARM AGRICULTURAL OCCUPATIONS. OF 77,868 WORKERS IN 384 FIRMS IN AREAS OF LESS THAN 25,000 POPULATION, 18 PERCENT WERE IN…

  3. Spatially distributed lateral nitrate transport at the catchment scale

    NASA Astrophysics Data System (ADS)

    Rode, M.; Franko, U.; Hesser, F.

    2010-12-01

    In river catchments, nitrogen transformation and storage processes during lateral transport are important in controlling nitrogen loads of surface waters. There is a lack of approaches which capture lateral flows and associated nitrogen transformation in a spatially distributed way. The aim of this paper is to develop a new conceptual nitrogen transport and transformation model which simulates the lateral nitrate transport in subsurface flow from the source area to the receiving water body. The developed tool is based on the Object Modelling System (OMS) framework and consists of the analytical spatially distributed hydrological model J2000, the nitrate recharge model Meta Candy and a new groundwater nitrogen routing component. The nitrogen subsurface transport component uses a variable number of sub storage layers for each hydrological response unit. Nitrate degradation in groundwater is calculated stoichiometrically according to a predefined amount on oxidizable substrate (pyrite and sedimentary organic matter) depending on the rock type. The decrease of subsurface nitrate reduction capacity can be simulated both spatially and over time. The new modelling approach was tested in a small agricultural lower mountain range catchment of Thuringia, Germany. The calibration of the nitrogen model using a four year period showed reasonable results for nitrate load calculations with a Nash and Sutcliff coefficient of 0.78. The three year validation period produced NS values of 0.75. There was a clear relationship of the goodness-of-fit between the hydrological simulations and the nitrate concentration calculations. Due to short residence times of the interflow nitrate degradation was restricted to slow base flow components. The new approach can be used to target nitrogen source areas within a catchment and assess the impact of these source areas on the nitrogen load of surface waters in a spatially distributed manner.

  4. Pesticides in soils and ground water in selected irrigated agricultural areas near Havre, Ronan, and Huntley, Montana

    USGS Publications Warehouse

    Clark, D.W.

    1990-01-01

    Three areas in Montana representing a range of agricultural practices and applied pesticides, were studied to document whether agricultural pesticides are being transported into the soil and shallow groundwater in irrigated areas. Analytical scans for triazine herbicides, organic-acid herbicides, and carbamate insecticides were performed on soil and shallow groundwater samples. The results indicate pesticide residue in both types of samples. The concentrations of pesticides in the groundwater were less than Federal health-advisory limits. At the Havre Agricultural Experiment Station, eight wells were installed at two sites. All four soil samples and two of four water samples collected after application of pesticides contained detectable concentrations of atrazine or dicamba. In an area where seed potatoes are grown near Ronan, eight wells were installed at two sites. Pesticides were not detected after initial application of pesticides and irrigation water. The site was resampled after irrigation water was reapplied, and aldicarb metabolities were detected in four of five soil samples and one of five water samples. At the Huntley Agricultural Experiment Station, five wells were installed in a no-tillage corn field where atrazine was applied in 1987. Soil and water samples were collected in June and July 1988; pesticides were not detected in any samples. Results indicate residue of two pesticides in soil samples and three soluble pesticides in groundwater samples. Therefore, irrigated agricultural areas in Montana might be susceptible to transport of soluble pesticides through permeable soil to the shallow groundwater system. (USGS)

  5. Assessing and monitoring soil quality at agricultural waste disposal areas-Soil Indicators

    NASA Astrophysics Data System (ADS)

    Doula, Maria; Kavvadias, Victor; Sarris, Apostolos; Lolos, Polykarpos; Liakopoulou, Nektaria; Hliaoutakis, Aggelos; Kydonakis, Aris

    2014-05-01

    The necessity of elaborating indicators is one of the priorities identified by the United Nations Convention to Combat Desertification (UNCCD). The establishment of an indicator monitoring system for environmental purposes is dependent on the geographical scale. Some indicators such as rain seasonality or drainage density are useful over large areas, but others such as soil depth, vegetation cover type, and land ownership are only applicable locally. In order to practically enhance the sustainability of land management, research on using indicators for assessing land degradation risk must initially focus at local level because management decisions by individual land users are taken at this level. Soils that accept wastes disposal, apart from progressive degradation, may cause serious problems to the surrounding environment (humans, animals, plants, water systems, etc.), and thus, soil quality should be necessarily monitored. Therefore, quality indicators, representative of the specific waste type, should be established and monitored periodically. Since waste composition is dependent on their origin, specific indicators for each waste type should be established. Considering agricultural wastes, such a specification, however, could be difficult, since almost all agricultural wastes are characterized by increased concentrations of the same elements, namely, phosphorous, nitrogen, potassium, sulfur, etc.; contain large amounts of organic matter; and have very high values of chemical oxygen demand (COD), biochemical oxygen demand (BOD), and electrical conductivity. Two LIFE projects, namely AgroStrat and PROSODOL are focused on the identification of soil indicators for the assessment of soil quality at areas where pistachio wastes and olive mill wastes are disposed, respectively. Many soil samples were collected periodically for 2 years during PROSODOL and one year during AgroStrat (this project is in progress) from waste disposal areas and analyzed for 23 parameters

  6. Hydrodynamic and hydrochemicalcharacterization of groundwater in agricultural area (case of Agafay farm-Western Haouz) Morocco

    NASA Astrophysics Data System (ADS)

    Sefiani, Salma; El mandour, Abdennabi; Laftouhi, Nour-Eddine; Khalil, Nourdine; Chehbouni, Abdelghani; Jarlan, Lionel; Hanich, Lahoucine; Khabba, Said; Hamaoui, Addi; Kamal, Safia

    2016-04-01

    Water resources play an important role in the socio-economic development of the Haouz plain. The agriculture and tourism are two essential components of this development. They represent more than 85% of the water consumption of the Tensift catchment. Under a semi-arid climate, according to hydric stress water used for irrigation essential for most crops, comes from pumping in groundwater from the unconfined aquifer of the Haouz. The use of groundwater for irrigation causes problems of soil degradation by the intensification of salinization processes, sodisation or alkalizing at several degrees. These situations are closely related to the natural characteristics of the environment (soil and climate) and the modalities of water management dedicated for irrigation highly affected by water quality. It is in this sense that the study was conducted in an irrigated citrus orchard drip, located in the western part of Haouz at 35 km of Marrakesh. The aim of this study is to characterize the area on hydrogeological and hydrochemical point of view, on the basis of a measurement and sampling campaign of thirty wells corresponding to June 2014. The piezometric map shows parallel flow lines oriented northwest. The aquifer recharge is ensured by lateral flow from the High Atlas and by the infiltration from surface water from Chichaoua, Assif El Mal and N'fis rivers. The low amount of flow rate recorded and measured in the vicinity of the study area at the sensing points are relative to the rise of Paleozoic substratum which reduces the recharge of the aquifer. On the hydrochemical level, groundwater quality is generally good (86% of cases). The strong mineralization is concentrated mainly in irrigated areas downstream along the flow direction of the aquifer and at the Guemassa substratum.

  7. Field Scale Groundwater Nitrate Loading Model for the Central Valley, California, 1945-Current

    NASA Astrophysics Data System (ADS)

    Harter, T.; Dzurella, K.; Bell, A.; Kourakos, G.

    2015-12-01

    Anthropogenic groundwater nitrate contamination in the Central Valley aquifer system, California, is widespread, with over 40% of domestic wells in some counties exceeding drinking water standards. Sources of groundwater nitrate include leaky municipal wastewater systems, municipal wastewater recharge, onsite wastewater treatment (septic) systems, atmospheric nitrogen deposition, animal farming, application of organic waste materials (sludge, biosolids, animal manure) to agricultural lands, and synthetic fertilizer. At the site or field scale, nitrogen inputs to the landscape are balanced by plant nitrogen uptake and harvest, atmospheric nitrogen losses, surface runoff of nitrogen, soil nitrogen storage changes, and leaching to groundwater. Irrigated agriculture is a dominant player in the Central Valley nitrogen cycle: The largest nitrogen fluxes are synthetic fertilizer and animal manure applications to cropland, crop nitrogen uptake, and groundwater nitrogen losses. We construct a historic field/parcel scale groundwater nitrogen loading model distinguishing urban and residential areas, individual animal farming areas, leaky wastewater lagoons, and approximately 50 different categories of agricultural crops. For non-agricultural landuses, groundwater nitrate loading is based on reported leaching values, animal population, and human population. For cropland, groundwater nitrate loading is computed from mass balance, taking into account diverse and historically changing management practices between different crops. Groundwater nitrate loading is estimated for 1945 to current. Significant increases in groundwater nitrate loading are associated with the expansion of synthetic fertilizer use in the 1950s to 1970s. Nitrate loading from synthetic fertilizer use has stagnated over the past 20 years due to improvements in nutrient use efficiency. However, an unbroken 60 year exponential increase in dairy production until the late 2000s has significantly impacted the

  8. Field Scale Groundwater Nitrate Loading Model for the Central Valley, California, 1945-Current

    NASA Astrophysics Data System (ADS)

    Harter, T.; Dzurella, K.; Bell, A.; Kourakos, G.

    2015-12-01

    Anthropogenic groundwater nitrate contamination in the Central Valley aquifer system, California, is widespread, with over 40% of domestic wells in some counties exceeding drinking water standards. Sources of groundwater nitrate include leaky municipal wastewater systems, municipal wastewater recharge, onsite wastewater treatment (septic) systems, atmospheric nitrogen deposition, animal farming, application of organic waste materials (sludge, biosolids, animal manure) to agricultural lands, and synthetic fertilizer. At the site or field scale, nitrogen inputs to the landscape are balanced by plant nitrogen uptake and harvest, atmospheric nitrogen losses, surface runoff of nitrogen, soil nitrogen storage changes, and leaching to groundwater. Irrigated agriculture is a dominant player in the Central Valley nitrogen cycle: The largest nitrogen fluxes are synthetic fertilizer and animal manure applications to cropland, crop nitrogen uptake, and groundwater nitrogen losses. We construct a historic field/parcel scale groundwater nitrogen loading model distinguishing urban and residential areas, individual animal farming areas, leaky wastewater lagoons, and approximately 50 different categories of agricultural crops. For non-agricultural landuses, groundwater nitrate loading is based on reported leaching values, animal population, and human population. For cropland, groundwater nitrate loading is computed from mass balance, taking into account diverse and historically changing management practices between different crops. Groundwater nitrate loading is estimated for 1945 to current. Significant increases in groundwater nitrate loading are associated with the expansion of synthetic fertilizer use in the 1950s to 1970s. Nitrate loading from synthetic fertilizer use has stagnated over the past 20 years due to improvements in nutrient use efficiency. However, an unbroken 60 year exponential increase in dairy production until the late 2000s has significantly impacted the

  9. Effects of Land Use and Travel Time on the Distribution of Nitrate in the Kirkwood-Cohansey Aquifer System in Southern New Jersey

    USGS Publications Warehouse

    Kauffman, Leon J.; Baehr, Arthur L.; Ayers, Mark A.; Stackelberg, Paul E.

    2001-01-01

    Residents of the southern New Jersey Coastal Plain are increasingly reliant on the unconfined Kirkwood-Cohansey aquifer system for public water supply as a result of increasing population and restrictions on withdrawals from the deeper, confined aquifers. Elevated nitrate concentrations above background levels have been found in wells in the surficial aquifer system in agricultural and urban parts of this area. A three-dimensional steady-state ground-water-flow model of a 400-square-mile study area near Glassboro, New Jersey, was used in conjunction with particle tracking to examine the effects of land use and travel time on the distribution of nitrate in ground and surface water in southern New Jersey. Contributing areas and ground-water ages, or travel times, of water at ground-water discharge points (streams and wells) in the study area were simulated. Concentrations of nitrate were computed by linking land use and age-dependent nitrate concentrations in recharge to the discharge points. Median concentrations of nitrate in water samples collected during 1996 from shallow monitoring wells in different land-use areas were used to represent the concentration of nitrate in aquifer recharge since 1990. On the basis of upward trends in the use of nitrogen fertilizer, the concentrations of nitrate in aquifer recharge in agricultural and urban areas were assumed to have increased linearly from the background value in 1940 (0.07 mg/L as N) to the 1990 (2.5-14 mg/L as N) concentrations. Model performance was evaluated by comparing the simulation results to measured nitrate concentrations and apparent ground-water ages. Apparent ground-water ages at 32 monitoring wells in the study area determined from tritium/helium-3 ratios and sulfur hexafluoride concentrations favorably matched simulated travel times to these wells. Simulated nitrate concentrations were comparable to concentrations measured in 27 water-supply wells in the study area. A time series (1987-98) of nitrate

  10. Trace elements assessment in agricultural and desert soils of Aswan area, south Egypt: Geochemical characteristics and environmental impacts

    NASA Astrophysics Data System (ADS)

    Darwish, Mohamed Abdallah Gad; Pöllmann, Hebert

    2015-12-01

    Determination of chemical elements, Al, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, P, Pb, Sc, Sr, Ti, Y, and Zn have been performed in agricultural and desert soils and alfalfa (Medicago sativa) at Aswan area. Consequently, the pollution indices, univariate and multivariate statistical methods have been applied, in order to assess the geochemical characteristics of these elements and their impact on soil environmental quality and plant, and to reach for their potential input sources. The investigation revealed that the mean and range values of all element concentrations in agricultural soil are higher than those in desert soil. Furthermore, the agricultural soil displayed various degrees of enrichment and pollution of Cd, Zn, Mo, Co, P, Ti, Pb. The geochemical pattern of integrated pollution indices gave a clear image of extreme and strong pollution in the agricultural soil stations, their poor quality with high risk to human health and considered as a tocsin for an alert. In contrast, the desert soil is the good environmental quality and safe for plant, animal and human health. Alfalfa is tolerant plant and considered as a biomarker for P and Mo in polluted agricultural soil. Four geochemical associations of analyzing elements in agricultural soil and three ones in desert soil have been generated, and their enhancements were essentially caused by various anthropogenic activities and geogenic sources. The investigation also revealed that the broad extended desert soil is fruitful and promising as cultivable lands for agricultural processes in the futures.

  11. Estimating the Probability of Elevated Nitrate Concentrations in Ground Water in Washington State

    USGS Publications Warehouse

    Frans, Lonna M.

    2008-01-01

    Logistic regression was used to relate anthropogenic (manmade) and natural variables to the occurrence of elevated nitrate concentrations in ground water in Washington State. Variables that were analyzed included well depth, ground-water recharge rate, precipitation, population density, fertilizer application amounts, soil characteristics, hydrogeomorphic regions, and land-use types. Two models were developed: one with and one without the hydrogeomorphic regions variable. The variables in both models that best explained the occurrence of elevated nitrate concentrations (defined as concentrations of nitrite plus nitrate as nitrogen greater than 2 milligrams per liter) were the percentage of agricultural land use in a 4-kilometer radius of a well, population density, precipitation, soil drainage class, and well depth. Based on the relations between these variables and measured nitrate concentrations, logistic regression models were developed to estimate the probability of nitrate concentrations in ground water exceeding 2 milligrams per liter. Maps of Washington State were produced that illustrate these estimated probabilities for wells drilled to 145 feet below land surface (median well depth) and the estimated depth to which wells would need to be drilled to have a 90-percent probability of drawing water with a nitrate concentration less than 2 milligrams per liter. Maps showing the estimated probability of elevated nitrate concentrations indicated that the agricultural regions are most at risk followed by urban areas. The estimated depths to which wells would need to be drilled to have a 90-percent probability of obtaining water with nitrate concentrations less than 2 milligrams per liter exceeded 1,000 feet in the agricultural regions; whereas, wells in urban areas generally would need to be drilled to depths in excess of 400 feet.

  12. Evaluation of the MODIS Albedo Product over a Heterogeneous Agricultural Area

    NASA Technical Reports Server (NTRS)

    Sobrino, Jose Antonio; Franch, B.; Oltra-Carrio, R.; Vermote, E. F.; Fedele, E.

    2013-01-01

    In this article, the Moderate Resolution Imaging Spectroradiometer (MODIS) Bidirectional Reflectance Distribution Function (BRDF)/Albedo product (MCD43) is evaluated over a heterogeneous agricultural area in the framework of the Earth Observation: Optical Data Calibration and Information Extraction (EODIX) project campaign, which was developed in Barrax (Spain) in June 2011. In this method, two models, the RossThick-LiSparse-Reciprocal (RTLSR) (which corresponds to the MODIS BRDF algorithm) and the RossThick-Maignan-LiSparse-Reciprocal (RTLSR-HS), were tested over airborne data by processing high-resolution images acquired with the Airborne Hyperspectral Scanner (AHS) sensor. During the campaign, airborne images were retrieved with different view zenith angles along the principal and orthogonal planes. Comparing the results of applying the models to the airborne data with ground measurements, we obtained a root mean square error (RMSE) of 0.018 with both RTLSR and RTLSR-HS models. The evaluation of the MODIS BRDF/Albedo product (MCD43) was performed by comparing satellite images with AHS estimations. The results reported an RMSE of 0.04 with both models. Additionally, taking advantage of a homogeneous barley pixel, we compared in situ albedo data to satellite albedo data. In this case, the MODIS albedo estimation was (0.210 +/- 0.003), while the in situ measurement was (0.204 +/- 0.003). This result shows good agreement in regard to a homogeneous pixel.

  13. Distribution and accumulation of hexachlorobutadiene in soils and terrestrial organisms from an agricultural area, East China.

    PubMed

    Tang, Zhenwu; Huang, Qifei; Cheng, Jiali; Qu, Dan; Yang, Yufei; Guo, Wei

    2014-10-01

    Hexachlorobutadiene (HCBD) is a potential persistent organic pollutant that has been found in abiotic environments and organisms. However, information on HCBD in soils and its accumulation in terrestrial food chains is scarce. This study investigated the accumulation of HCBD in soils, plants, and terrestrial fauna in a typical agricultural area in Eastern China, and drew comparisons with organochlorine pesticides (OCPs). The HCBD concentrations in soils were <0.02-3.1ng/g dry weight, which were similar to α-endosulfan concentrations but much lower than the concentrations of some other OCPs. The HCBD soil-plant accumulation factors, 8.5-38.1, were similar to those of o,p'-DDT and higher than those of HCHs and p,p'-DDT, indicating that HCBD is strongly bioaccumulated by rice and vegetables. HCBD concentrations of 1.3-8.2ng/g lipid weight were found in herbivorous insects, earthworms, and Chinese toads. The biomagnification factor, the ratio between the lipid-normalized concentrations in the predator and the prey, was found to be 0.16-0.64 for different food chains of Chinese toads, so HCBD was found not to biomagnify, which is in contrast with OCPs. Further research into whether HCBD is biomagnified in high trophic level organisms or through the entire terrestrial food web is required. PMID:25124679

  14. Landowners' incentives for constructing wetlands in an agricultural area in south Sweden.

    PubMed

    Hansson, Anna; Pedersen, Eja; Weisner, Stefan E B

    2012-12-30

    Eutrophication of the Baltic Sea has in Sweden led to the initiation of government schemes aiming to increase wetland areas in agricultural regions and thereby reduce nutrient transport to the sea. Landowners play a significant role as providers of this ecosystem service and are currently offered subsidies to cover their costs for constructing and maintaining wetlands. We undertook a grounded theory study, in which landowners were interviewed, aiming at identifying landowners' incentives for constructing wetlands on their land. The study showed that adequate subsidies, additional services that the wetland could provide to the landowner, local environmental benefits, sufficient knowledge, and peers' good experiences could encourage landowners to construct wetlands. Perceived hindrances were burdensome management, deficient knowledge, time-consuming application procedures and unclear effectiveness of nutrient reduction. The main reason for not creating a wetland, however, was that the land was classified as productive by the landowner, i.e., suitable for food production. Current schemes are directed toward landowners as individuals and based on subsidies to cover costs. We propose that landowners instead are approached as ecosystem service entrepreneurs and contracted after a tendering process based on nutrient reduction effects. This would lead to new definitions of production and may stimulate improved design and placement of wetlands. PMID:23064246

  15. Impacts of rainfall events on runoff water quality in an agricultural environment in temperate areas.

    PubMed

    Delpla, Ianis; Baurès, Estelle; Jung, Aude-Valérie; Thomas, Olivier

    2011-04-01

    Since a rise in dissolved organic carbon (DOC) concentrations has been observed for surface waters at least over the last two decades, a change in weather conditions (temperature and precipitations) has been proposed to partly explain this increase. While the majority of DOC delivery from soils to stream occurs during rainfall events, a better understanding of the rainfall influence on DOC release is needed. This study has been conducted in Brittany, western France, on agricultural experimental plots receiving either cattle manure (CM) or pig slurry (PS) as fertilizers in accordance with local practices. Each plot was instrumented with a flow meter and an auto sampler for runoff measurements. The results show that export of DOC during high intensity events is higher than during lower intensity rainfalls. Fertilization has a noticeable impact on total organic carbon (TOC) fluxes with an increase of five to seven folds for PS and CM respectively. If TOC shock load occurs shortly after the rainfall peak, DOC maximum appears with the first flush of the event. Organic carbon (OC) is mainly under colloidal (41.2%) and soluble (23.9%) forms during the first stage of a rainfall event and a control of rainfall intensity on OC colloidal transport is suggested. These findings highlight the potential risk of receiving water quality degradation due to the increase of heavier rainfall events with climate change in temperate areas.

  16. Wide-area mapping of small-scale features in agricultural landscapes using airborne remote sensing

    NASA Astrophysics Data System (ADS)

    O'Connell, Jerome; Bradter, Ute; Benton, Tim G.

    2015-11-01

    Natural and semi-natural habitats in agricultural landscapes are likely to come under increasing pressure with the global population set to exceed 9 billion by 2050. These non-cropped habitats are primarily made up of trees, hedgerows and grassy margins and their amount, quality and spatial configuration can have strong implications for the delivery and sustainability of various ecosystem services. In this study high spatial resolution (0.5 m) colour infrared aerial photography (CIR) was used in object based image analysis for the classification of non-cropped habitat in a 10,029 ha area of southeast England. Three classification scenarios were devised using 4 and 9 class scenarios. The machine learning algorithm Random Forest (RF) was used to reduce the number of variables used for each classification scenario by 25.5 % ± 2.7%. Proportion of votes from the 4 class hierarchy was made available to the 9 class scenarios and where the highest ranked variables in all cases. This approach allowed for misclassified parent objects to be correctly classified at a lower level. A single object hierarchy with 4 class proportion of votes produced the best result (kappa 0.909). Validation of the optimum training sample size in RF showed no significant difference between mean internal out-of-bag error and external validation. As an example of the utility of this data, we assessed habitat suitability for a declining farmland bird, the yellowhammer (Emberiza citronella), which requires hedgerows associated with grassy margins. We found that ∼22% of hedgerows were within 200 m of margins with an area >183.31 m2. The results from this analysis can form a key information source at the environmental and policy level in landscape optimisation for food production and ecosystem service sustainability.

  17. Wide-area mapping of small-scale features in agricultural landscapes using airborne remote sensing

    PubMed Central

    O’Connell, Jerome; Bradter, Ute; Benton, Tim G.

    2015-01-01

    Natural and semi-natural habitats in agricultural landscapes are likely to come under increasing pressure with the global population set to exceed 9 billion by 2050. These non-cropped habitats are primarily made up of trees, hedgerows and grassy margins and their amount, quality and spatial configuration can have strong implications for the delivery and sustainability of various ecosystem services. In this study high spatial resolution (0.5 m) colour infrared aerial photography (CIR) was used in object based image analysis for the classification of non-cropped habitat in a 10,029 ha area of southeast England. Three classification scenarios were devised using 4 and 9 class scenarios. The machine learning algorithm Random Forest (RF) was used to reduce the number of variables used for each classification scenario by 25.5 % ± 2.7%. Proportion of votes from the 4 class hierarchy was made available to the 9 class scenarios and where the highest ranked variables in all cases. This approach allowed for misclassified parent objects to be correctly classified at a lower level. A single object hierarchy with 4 class proportion of votes produced the best result (kappa 0.909). Validation of the optimum training sample size in RF showed no significant difference between mean internal out-of-bag error and external validation. As an example of the utility of this data, we assessed habitat suitability for a declining farmland bird, the yellowhammer (Emberiza citronella), which requires hedgerows associated with grassy margins. We found that ∼22% of hedgerows were within 200 m of margins with an area >183.31 m2. The results from this analysis can form a key information source at the environmental and policy level in landscape optimisation for food production and ecosystem service sustainability. PMID:26664131

  18. California GAMA Special Study: An isotopic and dissolved gas investigation of nitrate source and transport to a public supply well in California's Central Valley

    SciTech Connect

    Singleton, M J; Moran, J E; Esser, B K; Roberts, S K; Hillegonds, D J

    2010-04-14

    This study investigates nitrate contamination of a deep municipal drinking water production well in Ripon, CA to demonstrate the utility of natural groundwater tracers in constraining the sources and transport of nitrate to deep aquifers in the Central Valley. The goal of the study was to investigate the origin (source) of elevated nitrate and the potential for the deep aquifer to attenuate anthropogenic nitrate. The site is ideal for such an investigation. The production well is screened from 165-325 feet below ground surface and a number of nearby shallow and deep monitoring wells were available for sampling. Furthermore, potential sources of nitrate contamination to the well had been identified, including a fertilizer supply plant located approximately 1000 feet to the east and local almond groves. A variety of natural isotopic and dissolved gas tracers including {sup 3}H-{sup 3}He groundwater age and the isotopic composition of nitrate are applied to identify nitrate sources and to characterize nitrate transport. An advanced method for sampling production wells is employed to help identify contaminant contributions from specific screen intervals. Nitrate transport: Groundwater nitrate at this field site is not being actively denitrified. Groundwater parameters indicate oxic conditions, the dissolved gas data shows no evidence for excess nitrogen as the result of denitrification, and nitrate-N and -O isotope compositions do not display patterns typical of denitrification. Contaminant nitrate source: The ambient nitrate concentration in shallow groundwater at the Ripon site ({approx}12 mg/L as nitrate) is typical of shallow groundwaters affected by recharge from agricultural and urban areas. Nitrate concentrations in Ripon City Well 12 (50-58 mg/L as nitrate) are significantly higher than these ambient concentrations, indicating an additional source of anthropogenic nitrate is affecting groundwater in the capture zone of this municipal drinking water well. This

  19. Assessment of nitrate-N contamination in the Chunnakam aquifer system, Jaffna Peninsula, Sri Lanka.

    PubMed

    Vithanage, Meththika; Mikunthan, Thushyanthi; Pathmarajah, Selverajah; Arasalingam, Sutharsiny; Manthrithilake, Herath

    2014-01-01

    Jaffna peninsula in Sri Lanka is an area of intensive agriculture using extensive organic and inorganic nitrogenous compounds and hence, this study was focused on assessing vulnerability of karstic aquifer system with specific focus on nitrate contamination, and compare loads of nitrate from agriculture. The total number of the wells sampled in the Chunnakam aquifer is 44. The coverage of wells with measurements of nitrate and nitrite concentrations in the database covering the study period from Januray, 2011 to August, 2011. The intrinsic vulnerability of the area is estimated by the DRASTIC model and the modified DRASTIC method was used to determine the nitrate-specific vulnerability of the aquifers. Average concentrations of nitrate-N and nitrite-N during the study period were 4.869 and 0.014 mg/L respectively. The average number of wells exceeding permissible level of NO3-N is approximately 6-12, which means that about 14-28% out of the 44 wells. Modified DRASTIC (DI) index value computed as explained above increased from DI = 177 to a range of 182 to 197. In spite of the increase, the Modified DI values show that the aquifer vulnerability specific to nitrate contamination remains in "high" category. Although nitrogen loading at the domestic sources and irrigation is of the same order of magnitude, the loading from fertilizer input is much larger which is about 15 times higher. This finding suggests that the fertilizer input in agricultural areas constitute a significant contribution to the nitrogen content in the groundwater and soils in agricultural areas of Jaffna.

  20. Examination of Recovery from Salinization of Agricultural Area in Tamil Nadu State, INDIA due to the December 2004 Tsunami

    NASA Astrophysics Data System (ADS)

    Kume, Takashi; Umetsu, Chieko; Palanisami, K.

    This study examined salinization and desalinization in an agricultural area of Nagapatttinam district, Tamil Nadu state, India due to the December 2004 tsunami. To examine the damage and recovery of agricultural environment from the tsunami, we observed and collected soil, groundwater and vegetation data. Soil electrical conductivity steeply increased after the tsunami and soil pH slightly increased, but returned to pre-tsunami levels in the following year. Groundwater salinity might return to pre-tsunami levels by 2006. MODIS EVI values measured before and after the tsunami showed that vegetation damaged by the tsunami recovered to its pre-tsunami state by the next rice cropping season, called samba, which continues from August to February. These rapid rates of recovery were due to leaching salt from the highly permeable soils in the area by the monsoon rainfall. From these results, we conclude that agricultural environment of the district has mostly recovered one year after the tsunami.

  1. Evaporative loss from irrigated interrows in a highly advective semi-arid agricultural area

    NASA Astrophysics Data System (ADS)

    Agam, Nurit; Evett, Steven R.; Tolk, Judy A.; Kustas, William P.; Colaizzi, Paul D.; Alfieri, Joseph G.; McKee, Lynn G.; Copeland, Karen S.; Howell, Terry A.; Chávez, Jose L.

    2012-12-01

    Agricultural productivity has increased in the Texas High Plains at the cost of declining water tables, putting at risk the sustainability of the Ogallala Aquifer as a principal source of water for irrigated agriculture. This has led area producers to seek alternative practices that can increase water use efficiency (WUE) through more careful management of water. One potential way of improving WUE is by reducing soil evaporation (E), thus reducing overall evapotranspiration (ET). Before searching for ways to reduce E, it is first important to quantify E and understand the factors that determine its magnitude. The objectives of this study were (1) to quantify E throughout part of the growing season for irrigated cotton in a strongly advective semi-arid region; (2) to study the effects of LAI, days after irrigation, and measurement location within the row on the E/ET fraction; and (3) to study the ability of microlysimeter (ML) measures of E combined with sap flow gage measures of transpiration (T) to accurately estimate ET when compared with weighing lysimeter ET data and to assess the E/T ratio. The research was conducted in an irrigated cotton field at the Conservation & Production Research Laboratory of the USDA-ARS, Bushland, TX. ET was measured by a large weighing lysimeter, and E was measured by 10 microlysimeters that were deployed in two sets of 5 across the interrow. In addition, 10 heat balance sap flow gages were used to determine T. A moderately good agreement was found between the sum E + T and ET (SE = 1 mm or ˜10% of ET). It was found that E may account for >50% of ET during early stages of the growing season (LAI < 0.2), significantly decreasing with increase in LAI to values near 20% at peak LAI of three. Measurement location within the north-south interrows had a distinct effect on the diurnal pattern of E, with a shift in time of peak E from west to east, a pattern that was governed by the solar radiation reaching the soil surface. However, total

  2. [Division of agricultural areas based on the level of pollution with industrial toxic substances].

    PubMed

    Safonnikova, S M; Maksimova, G F; Iakhina, M P; Magzhanova, S A

    1993-10-01

    Investigation of soil in the region with oil processing industry showed that soil of agricultural fields 10 km around is much polluted and can be used only for growing of technical crops and perennial grasses for seeds. Soil 15-20 km around is less polluted, but also demands limitation in agricultural use, especially on low riverside parts.

  3. Training of Farmers in Island Agricultural Areas: The Case of Cyclades Prefecture

    ERIC Educational Resources Information Center

    Brinia, Vasiliki; Papavasileiou, Panagiotis

    2015-01-01

    Purpose: The purpose of this research is to explore the views of young farmers regarding the agricultural training, the training needs and content, as well as the implementation of information technology (IT) and the Internet in agricultural training. The research was conducted in the Greek islands of Cyclades. Methodology: A quantitative approach…

  4. Separation of agroclimatic areas for optimal crop growing within the framework of the natural-agricultural zoning of Russia

    NASA Astrophysics Data System (ADS)

    Bulgakov, D. S.; Rukhovich, D. I.; Shishkonakova, E. A.; Vil'chevskaya, E. V.

    2016-09-01

    The separation of agroclimatic areas for optimal crop growing within is suggested within the framework of the natural-agricultural zoning of Russia developed under the supervision of I. Karmanov. Overall, 64 agroclimatic areas have been separated in Russia. They are specified by the particular soil and agroclimatic conditions and by the particular crops recommended for cultivation. The biological potential of these crops should correspond to the soil potential of the given area. A combined scheme of the natural-agricultural zoning of Russia and the separated agroclimatic areas is presented. It is argued that the information contained in this scheme can be used for developing landscape-adaptive farming systems, land cadaster, and land valuation; it is also helpful for terrain and remote sensing monitoring of soil fertility on arable lands and for soilecological monitoring.

  5. Relationships between Rural Inhabitants and Their Landscapes in Areas of Intensive Agricultural Use: A Case Study in Quebec (Canada)

    ERIC Educational Resources Information Center

    Ruiz, Julie; Domon, Gerald

    2012-01-01

    An understanding of the relationships between local populations and the landscape is crucial for reintroducing the multifunctional character of landscapes in areas of intensive agricultural use. This study proposes to identify and compare the relationships that local populations, both farmers and non-farmers, maintain with their landscapes in…

  6. Notice on Organizing College Graduates to Help in Education, Agriculture, Medical Service, and Poverty Alleviation in Rural Areas (2006)

    ERIC Educational Resources Information Center

    Chinese Education and Society, 2008

    2008-01-01

    The Three Assistances and One Alleviation Plan issued in 2006 is an expansion of the Western China Program issued in 2003. Voluntary services in agricultural, educational, and medical areas by college graduates are organized through the implementation of this policy. The plan aims to recruit 20,000 graduates per year and has provided more detailed…

  7. Home Influences on the Academic Performance of Agricultural Science Students in Ikwuano Local Government Area of Abia State, Nigeria

    ERIC Educational Resources Information Center

    Ndirika, Maryann C.; Njoku, U. J.

    2012-01-01

    This study was conducted to investigate the home influences on the academic performance of agricultural science secondary school students in Ikwuano Local Government Area of Abia State. The instrument used in data collection was a validated questionnaire structured on a two point rating scale. Simple random sampling technique was used to select…

  8. Hot Spots and Hot Moments of Methylmercury Production Associated With Agricultural and Non-agricultural Wetlands of the Yolo Bypass Wildlife Area, California

    NASA Astrophysics Data System (ADS)

    Marvin-Dipasquale, M.; Windham-Myers, L.; Agee, J. L.; Kakouros, E.; Cox, M. H.; Fleck, J.; Alpers, C. N.; Stephenson, M.

    2008-12-01

    The Yolo Bypass Wildlife Area (YBWA) is part of the larger Yolo Bypass floodwater protection zone associated with the Sacramento River and the Sacramento-San Joaquin Delta, in California. While mercury contamination is widespread throughout the region due to historic mining practices, the Yolo Bypass is responsible for a high proportion of the aqueous methylmercury (MeHg) entering the Delta, and biota from the Yolo Bypass are particularly elevated in toxic MeHg. Land use in the YBWA includes seasonally flooded agricultural fields (white rice, wild rice, fallow fields), and permanently and seasonally flooded non-agricultural wetlands used for resident and migratory waterfowl. Mercury biogeochemistry was examined in 0-2 cm surface sediment, as a function of habitat type, wetland management, and agricultural practices during the 2007-08 crop year. In permanently flooded wetlands, MeHg concentrations varied within a narrow range (ca. 0.5-1.5 ng/g dry wt) throughout the study period. In contrast, the three types of agricultural fields had higher MeHg concentrations throughout the rice-growing season (June-Sept; ca. 1.5-3.5 ng/g), and exhibited the highest levels (ca. 3.3-6.3 ng/g) in the post-harvest winter period (Dec-Feb). Further, naturally dried sediment, sampled during July '08 from post-harvest drained fallow agricultural fields (prior to reflooding) had MeHg concentrations that were also quite elevated (3.1 +/- 1.5 ng/g). This suggests that the initial elevated concentrations of overlying water MeHg, sometimes measured soon after flooding previously dried fields, may be related to the release of MeHg formed during the previous wet season and trapped in dried sediment, as opposed to being MeHg newly produced by bacteria upon soil rewetting. These results indicate that the 'hot spots and hot moments' associated with MeHg production in this system are linked to hydrologic manipulations (wetting and drying) in the agricultural fields, and that the practice of post

  9. Mercury cycling in agricultural and non-agricultural wetlands in the Yolo Bypass Wildlife Area, California: bioaccumulation in small fish

    NASA Astrophysics Data System (ADS)

    Ackerman, J. T.; Eagles-Smith, C. A.; Miles, K. A.; Ricca, M. A.

    2007-12-01

    We examined the bioaccumulation of mercury in small fish within white rice, wild rice, and permanent wetland habitats at the Yolo Wildlife Area during the 2007 rice growing season. We introduced 30 mosquito fish in each of four cages placed at the inlet, center, and outlet (two cages) of each wetland in June, immediately after the white rice fields were re-flooded after being seeded. All fish were removed from their cages 60-days after their introduction, with the exception that ten fish from each of the second cages at the outlets were removed 30-days after introduction to assess temporal trends in mercury exposure. Mercury concentrations will be compared between fish that were introduced into cages and reference fish that originated from the same fish stock (Sacramento County Vector Control). We also measured fish length and mass both when they were introduced and collected to 1) control for growth effects on mercury bioaccumulation and 2) examine whether wetland habitat influenced growth rates. Fish are currently being analyzed for mercury and results will be available by the conference.

  10. Influence of sub-grid scale parameterizations on atmospheric variability over a heterogeneous agricultural area

    NASA Astrophysics Data System (ADS)

    Timmermans, Wim; Andreu, Ana; Porté-Agel, Fernando; Albertson, John

    2015-04-01

    viscosity and diffusivity is discussed using airborne and ground-based observations from a campaign (REFLEX-2012) over a heterogeneous agricultural area in the southern part of Spain.

  11. The Effect of Aquatic Vegetation on Water Quality in the Everglades Agricultural Area Canals

    NASA Astrophysics Data System (ADS)

    Gomez, S. M.; Bhadha, J. H.; Lang, T. A.; Josan, M. S.; Daroub, S. H.

    2011-12-01

    The canals in the Everglades Agricultural Area contain an abundance of floating aquatic vegetation (FAV) and submerged aquatic vegetation (SAV). These FAV flourish in waters with high phosphorus (P) concentrations and prevent the co-precipitation of P with the limestone bedrock (CaCO3). To test the effects of FAV and SAV and the presence of sediments on water quality in the canals, a lysimeter study was set up and stocked with FAV (water lettuce) and SAV (filamentous algae). There were four treatments with four replicates Treatment one contained limerock, sediment from the canals, and FAV. Treatment two contained limerock, sediment, and SAV. Treatment three contained limerock and FAV, while treatment four had limerock and SAV. After 7 days, the buckets were drained and replaced the water with new, high P canal water. Water samples were taken at 0, 0.25, 1, 3, and 7 days after each weekly water exchange. To test water quality soluble reactive P, total P, total dissolved P, Ca, and total organic carbon were analyzed. The impact of FAV and SAV and canal sediments on water quality will be discussed. We hypothesize water lettuce treatments will initially result in a reduction in P-concentration in all species, but will only serve as a short-term sink because of their high turn-over rate and production of labile high-P sediment (floc). In addition, we hypothesize the treatments with no sediment will have more P reduction because of the availability for P to co-precipitate with CaCO3.

  12. Dynamic factor analysis of groundwater quality trends in an agricultural area adjacent to Everglades National Park.

    PubMed

    Muñoz-Carpena, R; Ritter, A; Li, Y C

    2005-11-01

    The extensive eastern boundary of Everglades National Park (ENP) in south Florida (USA) is subject to one of the most expensive and ambitious environmental restoration projects in history. Understanding and predicting the water quality interactions between the shallow aquifer and surface water is a key component in meeting current environmental regulations and fine-tuning ENP wetland restoration while still maintaining flood protection for the adjacent developed areas. Dynamic factor analysis (DFA), a recent technique for the study of multivariate non-stationary time-series, was applied to study fluctuations in groundwater quality in the area. More than two years of hydrological and water quality time series (rainfall; water table depth; and soil, ground and surface water concentrations of N-NO3-, N-NH4+, P-PO4(3-), Total P, F-and Cl-) from a small agricultural watershed adjacent to the ENP were selected for the study. The unexplained variability required for determining the concentration of each chemical in the 16 wells was greatly reduced by including in the analysis some of the observed time series as explanatory variables (rainfall, water table depth, and soil and canal water chemical concentration). DFA results showed that groundwater concentration of three of the agrochemical species studied (N-NO3-, P-PO4(3-)and Total P) were affected by the same explanatory variables (water table depth, enriched topsoil, and occurrence of a leaching rainfall event, in order of decreasing relative importance). This indicates that leaching by rainfall is the main mechanism explaining concentration peaks in groundwater. In the case of N-NH4+, in addition to leaching, groundwater concentration is governed by lateral exchange with canals. F-and Cl- are mainly affected by periods of dilution by rainfall recharge, and by exchange with the canals. The unstructured nature of the common trends found suggests that these are related to the complex spatially and temporally varying land