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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. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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

  11. Groundwater nitrate pollution and human health risk assessment by using HHRA model in an agricultural area, NE China.

    PubMed

    Zhai, Yuanzheng; Zhao, Xiaobing; Teng, Yanguo; Li, Xiao; Zhang, Junjun; Wu, Jin; Zuo, Rui

    2017-03-01

    In order to learn the pollution circumstance of groundwater nitrate detailedly in Songnen Plain of Northeast China and estimate its potential risk to human health of local residents, a total of 389 groundwater samples were collected in 2014 and studied from residential areas and public water supply wells in 11 cities and counties in southeastern of Songnen Plain. The analysis results showed that the spatial distributions of main chemical components in groundwater had great variations with statistical concentrations in the order of TDS> HCO3> Ca> NO3> Cl> Na> SO4> Mg> K> NH4> NO2. As for NO3, it ranged from less than 0.02mg/L to 497mg/L with an average value of 39.46mg/L indicating an obviously anthropogenic pollution. Even more than 32% of the samples exceeded the Grade III threshold (20mg/L of N) according to China's standard. The results obtained from principal component analysis showed that high NO3 concentration could be attributed to human activities, especially the excessive use of chemical fertilizers in agriculture. Further, a human health risk assessment (HHRA) model derived from the US Environmental Protection Agency (USEPA) was applied to estimate the potential health risk of groundwater nitrate considering both drinking water and dermal contact pathways. The results indicated that potential health risks of adult males and females within about 60% of the area were at the acceptable level, while those within about 40% were beyond the acceptable level. The area at the acceptable level for children covered 49% of the total area while the same value for infants was 37%. The NO3 concentration in southeast and northeast of the study area was the highest so that residents in these regions were at the highest health risk. In conclusion, risk levels for different crowds in the study area varied obviously, generally in the order of infants> children> adult females> adult males, and the potential health risks of residents, especially minors and rural residents

  12. 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.

  13. Nitrate pollution of groundwater in the alsatian plain (France)—A multidisciplinary study of an agricultural area: The Central Ried of the ill river

    NASA Astrophysics Data System (ADS)

    Bernhard, C.; Carbiener, R.; Cloots, A. R.; Froehlicher, R.; Schenck, Ch.; Zilliox, L.

    1992-09-01

    The area studied is part of the “Ried Central” of the Ill river (Middle Alsatian plain in northeastern France). This area is located mainly in the present floodplain of the Ill. The closeness of the water table to the surface results in quasi general soil hydromorphism. The economic constraints of the last two decades led to deep changes in agricultural activities in the study area. These have essentially involved a marked extension of intensive cultivation of grain corn at the expense of grasslands. The study of the influence of this change on the parallel increase in the concentration of nitrate in groundwater is only feasible when a multidisciplinary approach is adopted. The analyses carried out in the field and in the laboratory show that nitrate reduction occurs in gleyed or peaty horizons of hydromorphic soils. The aptitude and efficiency of the permanent ambient vegetation (alluvial forests and grasslands) in retaining nitrate must be emphasized. The amount of nitrate eliminated from the aquifer by rivers fed by this aquifer is considerable. This evacuation of nitrate into the Ill is a fine example of waste and illustrates the absurdity of the economic situation responsible for excessive nitrogen fertilization of farmlands. In determining hazard zones, this study also proposes practical solutions to the problem of nitrate pollution: diminution of land area under cultivation, reintroduction of grasslands, and a more judicious use of nitrogen manure.

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

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

    PubMed Central

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

    2013-01-01

    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 15N-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. PMID:24145428

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

    PubMed

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

    2013-11-05

    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.

  4. 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.

  5. Different seasonality of nitrate export from an agricultural watershed and an urbanized watershed in Midwestern USA

    NASA Astrophysics Data System (ADS)

    Tian, S.; Youssef, M. A.; Richards, R. P.; Liu, J.; Baker, D. B.; Liu, Y.

    2016-10-01

    Land use/land cover is a critical factor affecting temporal dynamics of nitrate export from watersheds. Based on a long-term (>30 years) water quality monitoring program in the Western Lake Erie area, United States, this study compared seasonal variation of nitrate export from an agricultural watershed and an urbanized watershed. A seasonality index was adapted to quantitatively characterize seasonal variation of nitrate export from the two watersheds. Results showed that monthly nitrate concentrations from the two watersheds exhibited different seasonal variation. Seasonality index of monthly nitrate loading for the agricultural watershed is approximately 3 times of that from the urbanized watershed and the difference is statistically significant (p < 0.0001). Meanwhile, calculated historical seasonality indexes of monthly nitrate loading for both watersheds exhibited significant (p < 0.05) decreasing trends according to the non-seasonal Mann-Kendall test. The identified differences in seasonal nitrate export from the two watersheds were mainly attributed to their distinct nitrogen sources, physical and biogeochemical settings. The declining seasonality index of monthly nitrate loading from the agricultural watershed could be partially caused by historical climate change in the study region, especially increased temperature during winter. Urbanization could be one key factor contributing to the declining seasonality index of monthly nitrate loading from the urbanized watershed. Information derived from this study have practical implications for developing proper management practices to mitigate nitrate pollution in Midwestern United States.

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. 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

    ... International Trade Administration Solid Agricultural Grade Ammonium Nitrate from Ukraine: Continuation of... revocation of the antidumping duty order \\1\\ on solid agricultural grade ammonium nitrate from Ukraine would... of the Order. \\1\\ See Antidumping Duty Order: Solid Agricultural Grade Ammonium Nitrate from...

  11. 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

    ... Agricultural Grade Ammonium Nitrate from Ukraine: Final Results of the Expedited Second Sunset Review of the... antidumping duty order on solid agricultural grade ammonium nitrate from Ukraine. The Department has conducted... on solid agricultural grade ammonium nitrate from Ukraine, pursuant to section 751(c) of the...

  12. In-stream bioreactor for agricultural nitrate treatment.

    PubMed

    Robertson, W D; Merkley, L C

    2009-01-01

    Nitrate from agricultural activity contributes to nutrient loading in surface water bodies such as the Mississippi River. This study demonstrates a novel in-stream bioreactor that uses carbonaceous solids (woodchips) to promote denitrification of agricultural drainage. The reactor (40 m3) was trenched into the bottom of an existing agricultural drainage ditch in southern Ontario (Avon site), and flow was induced through the reactor by construction of a gravel riffle in the streambed. Over the first 1.5 yr of operation, mean influent NO3-N of 4.8 mg L(-1) was attenuated to 1.04 mg L(-1) at a mean reactor flow rate of 24 L min(-1). A series of flow-step tests, facilitated by an adjustable height outlet pipe, demonstrated that nitrate mass removal generally increased with increasing flow rate. When removal rates were not nitrate-limited, areal mass removal ranged from 11 mg N m(-2) h(-1) at 3 degrees C to 220 mg N m(-2) h(-1) at 14 degrees C (n = 27), exceeding rates reported for some surface-flow constructed wetlands in this climatic region by a factor of about 40. Over the course of the field trial, reactor flow rates decreased as a result of silt accumulation on top of the gravel infiltration gallery. Design modifications are currently being implemented to mitigate the effects of siltation. In-stream reactors have the potential to be scaled larger and could be more manageable than attempting to address nitrate loading from individual tile drains. They could also work well in combination with other nitrate control techniques.

  13. Hydrological and environmental controls of the stream nitrate concentration and flux in a small agricultural watershed

    NASA Astrophysics Data System (ADS)

    Zhou, Y.; Xu, J. F.; Yin, W.; Ai, L.; Fang, N. F.; Tan, W. F.; Yan, F. L.; Shi, Z. H.

    2017-02-01

    Nitrate exports from diffuse sources constitute a major cause of eutrophication and episodic acidification in inland aquatic systems, and remedial action requires the identification of the influencing factors associated with these nitrate exports. This paper examines the combined effects of watershed complexity on nitrate concentration and flux in terms of the hydrological and environmental factors in heterogeneous nested subwatersheds in the Danjiangkou Reservoir Area (DRA), China. We established 15 sampling sites in the main stream and tributaries and conducted biweekly sampling in 2008-2012 to monitor the nitrate exports. The hydrological and environmental indices within the watershed were divided into subwatersheds and considered as potential influencing factors. In consideration of the high co-linearity of these influencing factors, we used partial least squares regression (PLSR) to determine the associations between the stream nitrate concentration or flux and 26 selected watershed characteristics. The number of components was unequal for the nitrate concentration and flux models. The optimal models explained 66.4%, 60.0% and 59.9% of the variability in nitrate concentration and 74.7%, 67.1% and 58.0% of the variability in nitrate flux annually, in the dry season, and in the wet season, respectively. According to the variable importance in the projection (VIP) values, the dominant first-order factors for the nitrate concentration were as follows: the areal percentages of agricultural, forest and residential areas; followed by the slope; the largest patch index (LPI); the flow path gradient (FPG); the slope gradient variance (SGV); and the splitting index (SPLIT). In addition to these factors, the runoff coefficient (RC), flashiness index (FI), and patch density (PD) affected the changes in the nitrate flux. This study illustrates the influence of hydrological and environmental factors on seasonal water quality and can serve as guidelines for better watershed

  14. Dynamic regression modeling of daily nitrate-nitrogen concentrations in a large agricultural watershed.

    PubMed

    Feng, Zhujing; Schilling, Keith E; Chan, Kung-Sik

    2013-06-01

    Nitrate-nitrogen concentrations in rivers represent challenges for water supplies that use surface water sources. Nitrate concentrations are often modeled using time-series approaches, but previous efforts have typically relied on monthly time steps. In this study, we developed a dynamic regression model of daily nitrate concentrations in the Raccoon River, Iowa, that incorporated contemporaneous and lags of precipitation and discharge occurring at several locations around the basin. Results suggested that 95 % of the variation in daily nitrate concentrations measured at the outlet of a large agricultural watershed can be explained by time-series patterns of precipitation and discharge occurring in the basin. Discharge was found to be a more important regression variable than precipitation in our model but both regression parameters were strongly correlated with nitrate concentrations. The time-series model was consistent with known patterns of nitrate behavior in the watershed, successfully identifying contemporaneous dilution mechanisms from higher relief and urban areas of the basin while incorporating the delayed contribution of nitrate from tile-drained regions in a lagged response. The first difference of the model errors were modeled as an AR(16) process and suggest that daily nitrate concentration changes remain temporally correlated for more than 2 weeks although temporal correlation was stronger in the first few days before tapering off. Consequently, daily nitrate concentrations are non-stationary, i.e. of strong memory. Using time-series models to reliably forecast daily nitrate concentrations in a river based on patterns of precipitation and discharge occurring in its basin may be of great interest to water suppliers.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. A catchment-scale method to simulating the impact of historical nitrate loading from agricultural land on the nitrate-concentration trends in the sandstone aquifers in the Eden Valley, UK.

    PubMed

    Wang, Lei; Burke, Sean P

    2017-02-01

    Nitrate water pollution, which is mainly caused by agricultural activities, remains an international problem. It can cause serious long-term environmental and human health issues due to nitrate time-lag in the groundwater system. However, the nitrate subsurface legacy issue has rarely been considered in environmental water management. We have developed a simple catchment-scale approach to investigate the impact of historical nitrate loading from agricultural land on the nitrate-concentration trends in sandstones, which represent major aquifers in the Eden Valley, UK. The model developed considers the spatio-temporal nitrate loading, low permeability superficial deposits, dual-porosity unsaturated zones, and nitrate dilution in aquifers. Monte Carlo simulations were undertaken to analyse parameter sensitivity and calibrate the model using observed datasets. Time series of annual average nitrate concentrations from 1925 to 2150 were generated for four aquifer zones in the study area. The results show that the nitrate concentrations in 'St Bees Sandstones', 'silicified Penrith Sandstones', and 'non-silicified Penrith Sandstones' keep rising or stay high before declining to stable levels, whilst that in 'interbedded Brockram Penrith Sandstones' will level off after a slight decrease. This study can help policymakers better understand local nitrate-legacy issues. It also provides a framework for informing the long-term impact and timescale of different scenarios introduced to deliver water-quality compliance. This model requires relatively modest parameterisation and is readily transferable to other areas.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. MODELING LONG-TERM NITRATE BASE-FLOW LOADING FROM TWO AGRICULTURAL WATERSHEDS

    EPA Science Inventory

    Nitrate contamination of ground water from agricultural practices may be contributing to the eutrophication of the Chesapeake Bay, degrading water quality and aquatic habitats. Groundwater flow and nitrate transport and fate are modeled, using MODFLOW and MT3D computer models, in...

  13. Assessing the dynamics of fluvial nitrate over short stream reaches in watersheds impacted by agricultural pollution

    NASA Astrophysics Data System (ADS)

    Gurley, J. W.; Showers, W. J.; Osburn, C. L.; Levine, J. F.

    2011-12-01

    Elevated nitrate levels in many aquatic systems can be related to changes in land use/land cover and agricultural practices. However, these relations are often based on synoptic point sampling of independent drainage basins, neglecting in-stream processes that may affect nitrate dynamics upstream and resulting in correlations based on large spatial coverage. Understanding regional trends and implementing effective management strategies are hindered by the inability to determine the sources and dynamics of nitrate over stream reaches at small scales. To address this issue, continuous downstream measurements were made on two low-order streams draining small watersheds of mixed agricultural and natural land cover. Small, yet significant changes in nitrate concentration were observed at river lengths ranging from a few hundred meters to kilometers. This variability was related to the inputs of smaller streams and artificial drainages as well as the presence of natural dams. These patterns represent downstream nitrate variation as a stepped progression with little to no gradual in-stream processing over short distances. On both streams, average nitrate concentration downstream of inputs showed a positive correlation with proportion of agricultural land use within the input drainage basin while proportion of wetland cover correlated negatively with nitrate concentration in one stream. Reduction of nitrate downstream of natural dams indicates that these structures may serve as zones of nitrate removal in these low-order streams. These findings demonstrate the dynamic nature of nitrate and suggest that small-scale terrestrial and in-stream processes are of ecological importance when determining riverine nitrate influences in agricultural watersheds.

  14. The relative importance of microbial nitrate reduction processes in an agriculturally-impacted estuary

    NASA Astrophysics Data System (ADS)

    Cardarelli, E.; Francis, C. A.

    2013-12-01

    Human activities are increasing reactive nitrogen levels worldwide. Reactive nitrogen exists largely as nitrate and may be ecologically harmful to nutrient-limited systems. Nitrate loadings to the environment may be transformed by the microbial nitrate reduction processes of denitrification (converting nitrate to dinitrogen gas), or of dissimilatory nitrate reduction to ammonium (DNRA) (allowing reactive nitrogen to persist). The predominant nitrate reduction pathway largely determines the nitrogen removal capacity of the estuary. Therefore, identifying the relative importance of denitrification and DNRA in a given system provides insight into how much nitrate is transformed to dinitrogen and ammonium. Estuary sediments often have high nitrate reduction rates, but the environmental factors that determine which process prevails are underexplored. Nitrate availability and salinity are thought to influence which nitrate reduction process predominates. Elkhorn Slough is a small California estuary that experiences a range of nitrate concentrations (0 to over 2,000 μM) and salinities (0 to 33.5) depending on the agricultural runoff introduced through the Old Salinas River and the tidal influence. This study investigates how the fluctuating nutrient and salinity conditions found over the diel cycle at the interface of the Old Salinas River and Elkhorn Slough influences the nitrogen transformation rates observed. Benthic denitrification and DNRA are evaluated using whole sediment core incubations amended with an overlying 15NO3- labeled pool. Rates of denitrification and DNRA in the sediment are calculated using the isotope pairing technique. The results of this research will help elucidate the relative importance of dissimilatory nitrate removal pathways in an agriculturally-impacted estuary and ultimately reveal whether anthropogenic nitrate inputs are preserved or removed from the system.

  15. 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.

  16. 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.

  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. 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.

  2. 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

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. A hydro-economic modelling framework for optimal management of groundwater nitrate pollution from agriculture

    NASA Astrophysics Data System (ADS)

    Peña-Haro, Salvador; Pulido-Velazquez, Manuel; Sahuquillo, Andrés

    2009-06-01

    SummaryA hydro-economic modelling framework is developed for determining optimal management of groundwater nitrate pollution from agriculture. A holistic optimization model determines the spatial and temporal fertilizer application rate that maximizes the net benefits in agriculture constrained by the quality requirements in groundwater at various control sites. Since emissions (nitrogen loading rates) are what can be controlled, but the concentrations are the policy targets, we need to relate both. Agronomic simulations are used to obtain the nitrate leached, while numerical groundwater flow and solute transport simulation models were used to develop unit source solutions that were assembled into a pollutant concentration response matrix. The integration of the response matrix in the constraints of the management model allows simulating by superposition the evolution of groundwater nitrate concentration over time at different points of interest throughout the aquifer resulting from multiple pollutant sources distributed over time and space. In this way, the modelling framework relates the fertilizer loads with the nitrate concentration at the control sites. The benefits in agriculture were determined through crop prices and crop production functions. This research aims to contribute to the ongoing policy process in the Europe Union (the Water Framework Directive) providing a tool for analyzing the opportunity cost of measures for reducing nitrogen loadings and assessing their effectiveness for maintaining groundwater nitrate concentration within the target levels. The management model was applied to a hypothetical groundwater system. Optimal solutions of fertilizer use to problems with different initial conditions, planning horizons, and recovery times were determined. The illustrative example shows the importance of the location of the pollution sources in relation to the control sites, and how both the selected planning horizon and the target recovery time can

  8. Entomopathogenic nematodes in agricultural areas in Brazil.

    PubMed

    de Brida, Andressa Lima; Rosa, Juliana Magrinelli Osório; Oliveira, Cláudio Marcelo Gonçalves de; Castro, Bárbara Monteiro de Castro E; Serrão, José Eduardo; Zanuncio, José Cola; Leite, Luis Garrigós; Wilcken, Silvia Renata Siciliano

    2017-04-06

    Entomopathogenic nematodes (EPNs) (Steinernematidae and Heterorhabditidae) can control pests due to the mutualistic association with bacteria that kill the host by septicemia and make the environment favorable for EPNs development and reproduction. The diversity of EPNs in Brazilian soils requires further study. The identification of EPNs, adapted to environmental and climatic conditions of cultivated areas is important for sustainable pest suppression in integrated management programs in agricultural areas of Brazil. The objective was to identify EPNs isolated from agricultural soils with annual, fruit and forest crops in Brazil. Soil samples were collected and stored in 250 ml glass vials. The nematodes were isolated from these samples with live bait traps ([Galleria mellonella L. (Lepidoptera: Pyralidae) larvae]. Infective juveniles were collected with White traps and identified by DNA barcoding procedures by sequencing the D2/D3 expansion of the 28S rDNA region by PCR. EPNs identified in agricultural areas in Brazil were Heterorhabditis amazonensis, Metarhabditis rainai, Oscheios tipulae and Steinernema rarum. These species should be considered pest biocontrol agents in Brazilian agricultural areas.

  9. 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…

  10. Entomopathogenic nematodes in agricultural areas in Brazil

    PubMed Central

    de Brida, Andressa Lima; Rosa, Juliana Magrinelli Osório; Oliveira, Cláudio Marcelo Gonçalves de; Castro, Bárbara Monteiro de Castro e; Serrão, José Eduardo; Zanuncio, José Cola; Leite, Luis Garrigós; Wilcken, Silvia Renata Siciliano

    2017-01-01

    Entomopathogenic nematodes (EPNs) (Steinernematidae and Heterorhabditidae) can control pests due to the mutualistic association with bacteria that kill the host by septicemia and make the environment favorable for EPNs development and reproduction. The diversity of EPNs in Brazilian soils requires further study. The identification of EPNs, adapted to environmental and climatic conditions of cultivated areas is important for sustainable pest suppression in integrated management programs in agricultural areas of Brazil. The objective was to identify EPNs isolated from agricultural soils with annual, fruit and forest crops in Brazil. Soil samples were collected and stored in 250 ml glass vials. The nematodes were isolated from these samples with live bait traps ([Galleria mellonella L. (Lepidoptera: Pyralidae) larvae]. Infective juveniles were collected with White traps and identified by DNA barcoding procedures by sequencing the D2/D3 expansion of the 28S rDNA region by PCR. EPNs identified in agricultural areas in Brazil were Heterorhabditis amazonensis, Metarhabditis rainai, Oscheios tipulae and Steinernema rarum. These species should be considered pest biocontrol agents in Brazilian agricultural areas. PMID:28382937

  11. 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

  12. Nitrate removal effectiveness of a riparian buffer along a small agricultural stream in western Oregon.

    PubMed

    Wigington, P J; Griffith, S M; Field, J A; Baham, J E; Horwath, W R; Owen, J; Davis, J H; Rain, S C; Steiner, J J

    2003-01-01

    The Willamette Valley of Oregon has extensive areas of poorly drained, commercial grass seed lands. Little is know about the ability of riparian areas in these settings to reduce nitrate in water draining from grass seed fields. We established two study sites with similar soils and hydrology but contrasting riparian vegetation along an intermittent stream that drains perennial ryegrass (Lolium perenne L.) fields in the Willamette Valley of western Oregon. We installed a series of nested piezometers along three transects at each site to examine NO3-N in shallow ground water in grass seed fields and riparian areas. Results showed that a noncultivated riparian zone comprised of grasses and herbaceous vegetation significantly reduced NO3-N concentrations of shallow ground water moving from grass seed fields. Darcy's law-based estimates of shallow ground water flow through riparian zone A/E horizons revealed that this water flowpath could account for only a very small percentage of the streamflow. Even though there is great potential for NO3-N to be reduced as water moves through the noncultivated riparian zone with grass-herbaceous vegetation, the potential was not fully realized because only a small proportion of the stream flow interacts with riparian zone soils. Consequently, effective NO3-N water quality management in poorly drained landscapes similar to the study watershed is primarily dependent on implementation of sound agricultural practices within grass seed fields and is less influenced by riparian zone vegetation. Wise fertilizer application rates and timing are key management tools to reduce export of NO3-N in stream waters.

  13. 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.

  14. 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

  15. 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.

  16. Development of a GIS method to localize critical source areas of diffuse nitrate pollution.

    PubMed

    Orlikowski, D; Bugey, A; Périllon, C; Julich, S; Guégain, C; Soyeux, E; Matzinger, A

    2011-01-01

    The present study aimed at developing a universal method for the localization of critical source areas (CSAs) of diffuse nitrate (NO3-) pollution in rural catchments with low data availability. Based on existing methods, land use, soil, slope, riparian buffer strips and distance to surface waters were identified as the most relevant indicator parameters for diffuse agricultural NO3- pollution. The five parameters were averaged in a GIS-overlay to localize areas with low, medium and high risk of NO3- pollution. A first application of the GIS approach to the Ic catchment in France, showed that identified CSAs were in good agreement with results from river monitoring and numerical modelling. Additionally, the GIS approach showed low sensitivity to single parameters, which makes it robust to varying data availability. As a result, the tested GIS-approach provides a promising, easy-to-use CSA identification concept, applicable for a wide range of rural catchments.

  17. Practices to reduce nitrate leaching and increase nitrogen use efficiency in irrigated agriculture

    NASA Astrophysics Data System (ADS)

    Quemada, Miguel; Baranski, Marcin; Nobel de Lange, Majimcha; Vallejo, Antonio; Cooper, Julia

    2013-04-01

    Despite the large body of research in irrigated agriculture, it is still not clear which practices most effectively reduce nitrate leaching (NL) while maintaining crop yield. A meta-analysis (MA) of published experimental results from agricultural irrigated systems was conducted to identify those agricultural practices that have proven effective at reducing NL and to quantify the scale of reduction that can be achieved. Forty-four scientific articles were identified which investigated four main strategies (water and fertilizer management, use of cover crops and fertilizer technology) creating a database with 279 observations on NL and 166 on crop yield. Management practices that adjust water application to crop needs reduced NL by a mean of 80% without a reduction in crop yield. Improved fertilizer management reduced NL by 40%, and the best relationship between yield and NL was obtained when applying the recommended N fertilizer rate. Applications above the recommended rate increased leaching without enhancing yield. Replacing a fallow with a non-legume cover crop (CC) reduced NL by 50% while using a legume CC did not have any effect on NL. Legume CC increased yield and N use efficiency while yields following non-legume CC were not different from the fallow. Improved fertilizer technology also decreased NL but was the least effective of the selected strategies. The risk of nitrate leaching from irrigated systems is high, but optimum management practices may mitigate this risk and maintain crop yields while enhancing environmental sustainability.

  18. Optimal Management of Nitrate Pollution of Groundwater in Agricultural Watersheds Considering Environmental and Economic Constraints

    NASA Astrophysics Data System (ADS)

    Almasri, M. N.; Kaluarachchi, J. J.

    2007-05-01

    Groundwater pollution due to nitrogen species from various land use activities and practices is a common concern in most agricultural watersheds. Minimization of nonpoint source nitrogen pollution can be achieved by appropriate changes to land use practices to the extent of not affecting local economies that depend heavily on agricultural activities. Most prior research work focused on predicting nitrogen loading and/or fate and transport of nitrate in groundwater due to various agricultural activities. In this work, however, we propose to present a broad integrated methodology for the optimal management of nitrate contamination of ground water combining environmental assessment and economic cost evaluation through multi-criteria decision analysis. The proposed methodology incorporates an integrated physical modeling framework accounting for on-ground nitrogen loading and losses, soil nitrogen dynamics, and fate and transport of nitrate in ground water to compute the sustainable on-ground nitrogen loading such that the maximum contaminant level is not violated. A number of protection alternatives to stipulate the predicted sustainable on-ground nitrogen loading are evaluated using the decision analysis that employs the importance order of criteria approach for ranking and selection of the protection alternatives. The methodology was successfully demonstrated for the Sumas-Blaine aquifer in Washington State. The results showed the importance of using this integrated approach that predicts the sustainable on-ground nitrogen loadings and provides an insight to the economic consequences generated in satisfying the environmental constraints. The results also show that the proposed decision analysis framework, within certain limitation, is effective when selecting alternatives with competing demands.

  19. 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

  20. 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.

  1. 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

  2. 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

  3. Hurricane Katrina induced nutrient runoff from an agricultural area to coastal waters in Biscayne Bay, Florida

    NASA Astrophysics Data System (ADS)

    Zhang, Jia-Zhong; Kelble, Christopher R.; Fischer, Charles J.; Moore, Lloyd

    2009-09-01

    Water quality surveys conducted in Biscayne Bay, Florida, indicated enhanced nutrient input coupled with increased runoff as a result of precipitation associated with Hurricane Katrina. Nutrient concentrations before Katrina ranged from 0.06-24.2 μM (mean 3.3 μM) for nitrate and 0.01-0.18 μM (mean 0.1 μM) for soluble reactive phosphate. Five days after Katrina, nitrate concentrations ranged from 0.87-80.0 μM (mean 17.0 μM), with a bay-wide mean increase of 5.2-fold over pre-hurricane levels. Soluble reactive phosphate concentrations ranged from 0.07-0.62 μM (mean 0.2 μM), with a bay-wide mean increase of 2-fold over pre-hurricane levels. The maximum concentrations for both nitrate and soluble reactive phosphate were found at a water quality monitoring station near the mouth of Mowry Canal, which drains an agricultural area in the southern Biscayne Bay watershed near Homestead, Florida. At this station, nitrate and soluble reactive phosphate concentrations increased 7- and 10-fold, respectively. Storm-induced fertilizer runoff from this agricultural area caused a bay-wide increase in nutrient concentrations after Hurricane Katrina. Nutrient concentrations in the bay returned to pre-hurricane levels within three months after Hurricane Katrina, showing the resiliency of the Biscayne Bay ecosystem.

  4. 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)

  5. 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.

  6. 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

  7. 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.

  8. [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.

  9. Recurrent diarrhea in children living in areas with high levels of nitrate in drinking water.

    PubMed

    Gupta, S K; Gupta, R C; Gupta, A B; Seth, A K; Bassin, J K; Gupta, A; Sharma, M L

    2001-01-01

    Given that there was documented evidence of an association between diarrhea and high nitrate ingestion, the authors examined drinking water nitrate concentration and its possible correlation(s) with methemoglobin levels, cytochrome b5 reductase activity, and recurrent diarrhea. In addition, the authors studied histopathological changes in the intestines of rabbits in an animal model. Five village areas were studied, and nitrate concentrations (expressed in mg of nitrate per liter of water) of 26, 45, 95, 220, and 459 existed in the respective villages. The study included 88 randomly selected children who were 8 yr of age or younger; they represented 10% of the total population of each of the areas. Detailed histories of recurrent diarrhea were noted, and medical examinations were conducted. Cytochrome b5 reductase activity and methemoglobin levels were estimated biochemically. Collected data were analyzed statistically with Microsoft Excel software. In addition, the authors exposed rabbits to various levels of nitrate, and histopathological changes of the stomach and intestine (small and large) were evaluated. There was a strong relationship between nitrate concentration and recurrent diarrhea; 80% of the recurrent diarrhea cases were explained by nitrate concentration alone. In the rabbit intestines, lymphocytic infiltration and hyperplasia characterized the submucosa as nitrate concentrations increased.

  10. Decreasing nitrate-N loads to coastal ecosystems with innovative drainage management strategies in agricultural landscapes: An experimental approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Controlled drainage in agricultural ditches contributes to a drainage management strategy with potential environmental and production benefits. Innovative drainage strategies including spatially orientated low-grade weirs show promise to significantly improve nutrient (e.g. nitrate-N) reductions by...

  11. 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

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

    PubMed

    Duff, John H; Tesoriero, Anthony J; Richardson, William B; Strauss, Eric A; Munn, Mark 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.

  13. 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

  14. 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)

  15. 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

  16. 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

  17. 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)

  18. 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).

  19. Groundwater quality in alluvial and prolluvial areas under the influence of irrigated agriculture activities.

    PubMed

    Kovacevik, Biljana; Boev, Blazo; Panova, Vesna Zajkova; Mitrev, Sasa

    2016-12-05

    The aim of this study was to investigate the groundwater pollution from alluvial aquifers lying under surface agriculture activities in two geologically different areas: alluvial and prolluvial. The groundwater in investigated areas is neutral to alkaline (pH 7.05-8.45), and the major dissolved ions are bicarbonate and calcium. Groundwater samples from the alluvial area are characterized by nitrate concentration above the national maximum concentration limit (MCL) at 20.5% of samples [mean value (Me) 6.31 mg/L], arsenic concentrations greater than national MCL at 35.6% of investigated samples (Me 12.12 µg/L) and elevated concentrations of iron (Me 202.37 µg/L) and manganese (Me 355.22 µg/L) at 22.7% and 81% of investigated samples, respectively. Groundwater samples from the prolluvial area did not show significantly elevated concentrations of heavy metals, but the concentration of nitrate was considerably higher (Me 65.06 mg/L). Factor analysis positively correlates As with Mn and Fe, suggesting its natural origin. Nitrate was found in positive correlation with SO4(2-) and Ni but in negative with NH4(+), suggesting its anthropogenic origin and the relationship of these ions in the process of denitrification. The t-test analysis showed a significant difference between nitrate pollution of groundwater from alluvial and prolluvial areas. According to the chemical composition of groundwater, the process of denitrification is considered to be the main reason for the reduced presence of nitrate in the groundwater lying under alluvial deposits represented by chalk and sandstones. Denitrification in groundwater lying under prolluvial deposits represented by magmatic and metamorphic rock formations was not observed.

  20. Spatio-temporal dynamics of nitrogen in river-alluvial aquifer systems affected by diffuse pollution from agricultural sources: Implications for the implementation of the Nitrates Directive

    NASA Astrophysics Data System (ADS)

    Arauzo, M.; Valladolid, M.; Martínez-Bastida, J. J.

    2011-12-01

    SummaryReducing nitrate pollution from diffuse agricultural sources is the major environmental challenge in the two adjacent catchments of the Oja-Tirón and Zamaca rivers (La Rioja and Castilla y León, northern Spain). For this reason, part of their territory was designated a Nitrate Vulnerable Zone (NVZ) according to the Nitrates Directive. The Oja Alluvial Aquifer, the Tirón Alluvial Aquifer and their associated rivers are particularly vulnerable to nitrogen pollution due to the shallow water table, the high permeability of alluvial deposits, interconnections between the alluvial aquifers and surface waters and pressures from agriculture. To this end, nine sampling campaigns, organised on a semi-annual basis and focused on the rivers and alluvial aquifers of the two catchments, were carried out from April 2005 to April 2009. The main objectives of the study were: (1) to investigate the chemical forms of nitrogen in river-alluvial aquifer systems of the Oja-Tirón and Zamaca catchments, (2) to improve our understanding of the spatio-temporal patterns of nitrogen distribution in the alluvial aquifers and associated rivers by integrating hydrochemical data and hydrogeological and environmental parameters, (3) to estimate the amount of nitrogen exported from the rivers and alluvial aquifers to the River Ebro, and (4) to evaluate the suitability of the current method of designating NVZs in the area. High groundwater flow velocities in the upper alluvial zones favoured the advective transport of nitrate and generated a dilution effect. In these areas, inter-annual variations in nitrate concentrations were observed related to precipitation and N-input from agriculture. However, low flow velocities favoured processes of accumulation in the lower alluvial zones. Our results demonstrated that the entire alluvial surface was highly vulnerable, according to dynamics of the nitrogen in the river-alluvial aquifer systems being studied. The amount of nitrogen exported from

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. A methodology for assessing public health risk associated with groundwater nitrate contamination: a case study in an agricultural setting (southern Spain).

    PubMed

    Chica-Olmo, Mario; Peluso, Fabio; Luque-Espinar, Juan Antonio; Rodriguez-Galiano, Victor; Pardo-Igúzquiza, Eulogio; Chica-Rivas, Lucía

    2016-09-28

    Groundwater nitrate contamination from agriculture is of paramount environmental interest. A continuous consumption of polluted water as drinking water or for culinary purposes is by no means a minor hazard for people's health that must be studied. This research presents a new methodology for the spatial analysis of health risk rate from intake of nitrate-polluted groundwater. The method is illustrated through its application to a water quality sampling campaign performed in the south of Spain in 2003. The probability risk model used by the US Environmental Protection Agency has been applied, considering a residential intake framework and three representative population age groups (10, 40 and 65 years).The method was based upon coupling Monte Carlo simulations and geostatistics, which allowed mapping of the health risk coefficient (RC). The maps obtained were interpreted in the framework of water resources management and user's health protection (municipalities). The results showed waterborne health risk caused by nitrate-polluted water is moderately low for the region. The observed risk was larger for the elderly and children, although no significant differences were found among the three age groups (RC average values of 95th percentile for age of 0.37, 0.33 and 0.37, respectively). Significant risk values of RC > 1 were obtained for 10 % of the surface in the NW site of the study area, where the municipalities with the highest contamination thresholds are located (agricultural activity). Nitrate concentration and intake rate stood out as the main explanatory variables of the RC.

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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...

  17. 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.

  18. 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...

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. Assessing the impacts of Best Management Practices on nitrate pollution in an agricultural dominated lowland catchment considering environmental protection versus economic development.

    PubMed

    Haas, Marcelo B; Guse, Björn; Fohrer, Nicola

    2017-03-15

    Water quality is strongly affected by nitrate inputs in agricultural catchments. Best Management Practices (BMPs) are alternative practices aiming to mitigate the impacts derived from agricultural activities and to improve water quality. Management activities are influenced by different governmental policies like the Water Framework Directive (WFD) and the Renewable Energy Sources Act (EEG). Their distinct goals can be contrasting and hamper an integrated sustainable development. Both need to be addressed in the actual conjuncture in rural areas. Ecohydrological models like the SWAT model are important tools for land cover and land use changes investigation and the assessment of BMPs implementation effects on water quality. Thus, in this study, buffer strip, fertilization reduction and alternative crops were considered as BMPs and were implemented in the SWAT model for the Treene catchment. Their efficiency in terms of nitrate loads reduction related to implementation costs at the catchment scale was investigated. The practices correspond to the catchment conditions and are based on small and mid areal changes. Furthermore, the BMPs were evaluated from the perspective of ecologic and economic policies. The results evidenced different responses of the BMPs. The critical periods in winter were addressed by most of the BMPs. However, some practices like pasture land increase need to be implemented in greater area for better results in comparison to current activities. Furthermore, there is a greater nitrate reduction potential by combining BMPs containing fertilization reduction, buffer strips and soil coverage in winter. The discussion about efficiency showed the complexity of costs stipulation and the relation with arable land and yield losses. Furthermore, as the government policies can be divergent an integrated approach considering all the involved actors is important and seeks a sustainable development.

  4. 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.

  5. 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.

  6. Trichloroethylene, tetrachloroethylene, nitrates, and other chemicals in well water in the Fresno-Clovis Metropolitan Area.

    PubMed

    Kloos, H

    1997-01-01

    In this study, the author examined the spatial and temporal distribution of tetrachloroethylene, trichloroethylene, nitrate, and several other organic and inorganic chemicals in large community wells in the Fresno-Clovis Metropolitan Area and estimated the lifetime cancer risk associated with exposure to tetrachloroethylene and trichloroethylene. By 1992-1993, investigators found the industrial solvent tetrachloroethylene in 34 wells and found trichloroethylene in 16 wells. All wells had detectable levels of nitrate. In addition, investigators found radon, arsenic, cadmium, iron, manganese, trihalomethanes, and several other volatile organic chemicals in the wells, but only radon and arsenic posed a significant health risk. In 1995, 16 wells were closed because chemicals were found in them. Twenty-six of 248 (10.5%) active wells and 24 of 43 (55.8%) closed wells contained multiple contaminants, excluding nitrate. Between 1988 and 1993, concentrations of trichloroethylene, tetrachloroethylene, and nitrates increased in selected wells. Daily, monthly, and bimonthly variations in the concentrations of tetrachloroethylene, trichloroethylene, and nitrate were often considerable. Granulated activated carbon filtration reduced trichloroethylene levels in well water by 91%-95%, and the author examined its usefulness as a remedial measure. Estimated lifetime cancer risks for tetrachloroethylene and trichloroethylene were 1 excess cancer death per 9.5 million people and 1 excess death per 250 million, respectively. The author also included recommendations for the conduct of further epidemiological and environmental studies.

  7. 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

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

    NASA Astrophysics Data System (ADS)

    Ranalli, Anthony J.; Macalady, Donald L.

    2010-08-01

    SummaryWe 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

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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...

  14. 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...

  15. 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

  16. 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)

  17. 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

  18. 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

  19. 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.

  20. 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...

  1. 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.

  2. 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

  3. 21 CFR 181.33 - Sodium nitrate and potassium nitrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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.

  8. 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...

  9. 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...

  10. 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.

  11. 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.

  12. 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

  13. Removal of agricultural nitrate from tile-drainage effluent water using in-line bioreactors

    NASA Astrophysics Data System (ADS)

    Blowes, D. W.; Robertson, W. D.; Ptacek, C. J.; Merkley, C.

    1994-02-01

    Two 200-L fixed-bed bioreactors, containing porous-medium material of coarse sand and organic carbon (tree bark, wood chips and leaf compost), were used to treat NO 3 contamination from agricultural runoff. Flow from a farm-field drainage tile containing NO 3-N concentrations of 3-6 mg L -1 was successfully treated in the reactors (NO 3-N < 0.02 mg L -1) at a rate of 10-60 L day -1 over a 1-yr period. Treatment occurs by anaerobic denitrification promoted by the added solid-phase organic carbon. Because the reactor design is simple, economical to construct and maintenance free, it may provide a practical solution to the problem of treating redox-sensitive contaminants, such as NO 3, in agricultural runoff.

  14. 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

  15. 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

  16. Baseline geochemical characteristics of groundwater in the mountainous area of Jeju Island, South Korea: Implications for degree of mineralization and nitrate contamination

    NASA Astrophysics Data System (ADS)

    Koh, Dong-Chan; Chae, Gi-Tak; Yoon, Yoon-Yeol; Kang, Bong-Rae; Koh, Gi-Won; Park, Ki-Hwa

    2009-09-01

    SummaryHydrogeochemical characteristics of groundwater were investigated to elucidate baseline quality for basaltic aquifers of a mountainous area dominated by natural land cover in the volcanic island of Jeju, South Korea. Principal component analysis (PCA) resulted in four principal components (PC) of which PC1, PC3 and PC4 represented natural mineralization by water-rock interaction, while PC2 corresponded to anthropogenic contamination from nitrate sources. Hierarchical cluster analysis (HCA) was performed to assess the effect of the geochemical and hydrologic processes on each sample. Six sample groups, distinguished by total dissolved solids (TDS), nitrate concentration, and water type, resulted from the HCA: high-altitude springs, low-mineral water, nitrate-contaminated water, intermediate-mineral water, and two groups of high-mineral water. Water types were transformed from Na(Mg, Ca)-HCO 3 for low-mineral water to Na-HCO 3 for high-mineral water. Nitrate-contaminated water occurred near the boundary of natural and agricultural land uses of the western area. High-mineral water had higher calcite saturation states than other groups. The high-mineral water also had tritium ( 3H) values lower than 1.5 TU, indicating a significant contribution of old groundwater. In contrast, low-mineral water had tritium values of about 3 TU, which is close to those of rainwater. Geographically, the high-mineral water was concentrated in the southwestern area, where intermediate-mineral water was also found. This distribution was likely related to the presence of extensive trachytic rocks, which could have formed locally isolated aquifers, enabling prolonged water-rock interactions; the higher location of low-permeability hydrovolcanic tuffs in the subsurface of the southern area would also increase chances of tapping aquifers below the hydrovolcanic tuffs. The cumulative probability of TDS showed two breakpoints of 50 and 150 mg/L that distinguished high-altitude springs, low

  17. Problem area 1 effective water management in agriculture-Product area accomplishments-FY 11 - FY14

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The USDA Agricultural Research Service National Program 211 is composed of four components or problem areas. Problem Area 1, Effective Water Management in Agriculture, focuses on six areas of research that are crucial to safe and effective use of all water resources for agricultural production: 1) I...

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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

  4. 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.

  5. Temporal trends and relationships between groundwater and surface water nitrate concentrations in headwater agricultural catchments: what can we learn from a monitoring over 20 years?

    NASA Astrophysics Data System (ADS)

    Fovet, O.; Gascuel, C.; Faucheux, M.; Ruiz, L.; Aquilina, L.; Molenat, J.

    2012-04-01

    The intensification of agriculture during the 20th century led to strong issues on water quality related to nutrients enrichments in groundwater and surface water. In this context, Western France is an extreme case regarding to the high nitrate concentrations observed in rivers (around 7 mg N-NO3/l1 in average). In the early 90ies, an Environmental Research Observatory AgrHys has been created and instrumented to investigate the response time of hydro-chemical fluxes to landuse changes in agrohydrosystems. This observatory is part of a French Catchments Network (Critical Zone Observatory), and composed of two sites. Kervidy-Naizin monitoring has been recently analyzed to identify the effect of climatic factors on water quality, while we focus here on Kerbernez site. This site is composed of 5 first-order and adjacent catchments, less than 1 km^2, where land use agricultural practices have been recorded with precision. Hydrological, hydrochemical and climatic data were recorded over the last 20 years. Since 2001, the monitoring was extended to groundwater using piezometric measurements and chemical analyses. Previous studies [1] suggested that nitrate transport was essentially a transport limited process on this site. The long-term and extensive monitoring programs can help us understanding the effect of agricultural practices on nitrate concentration in streams. We reconsider this hypothesis 10 years later by analyzing if the streams nitrate concentrations reacted to the changes in agricultural practices. Different protocols of monitoring (manual vs. automatic measurements) are compared though the annual water fluxes at the outlet in order to estimate the incertitude on water discharge for such small streams. All the water balances computed were not equilibrated suggesting important subsurface flows. The high contribution of the shallow groundwater is confirmed by the hydrochemical data. Mean annual nitrate concentration in the drainage water is computed using two

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selenium (Se) contamination of groundwater is an environmental concern in several regions 25 around the world, particularly in areas where aquifer systems are underlain by Se-bearing 26 geologic formations such as marine shale. The fate and transport of Se is complicated by the 27 influence of other...

  7. 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.

  8. Comparison of some quality properties of soils around land-mined areas and adjacent agricultural fields.

    PubMed

    Ozturkmen, Ali Rıza; Kavdir, Yasemin

    2012-03-01

    When agricultural lands are no longer used for agriculture and allowed to recover its natural vegetation, soil organic carbon can accumulate in the soil. Measurements of soil organic carbon and aggregate stability changes under various forms of land use are needed for the development of sustainable systems. Therefore, comparison of soil samples taken from both agricultural and nearby area close to land-mined fields where no agricultural practices have been done since 1956 can be a good approach to evaluate the effects of tillage and agriculture on soil quality. The objective of this study was to compare tillage, cropping and no tillage effects on some soil-quality parameters. Four different locations along the Turkey-Syria border were selected to determine effects of tillage and cropping on soil quality. Each location was evaluated separately because of different soil type and treatments. Comparisons were made between non-tilled and non-cropped fallow since 1956 and adjacent restricted lands that were tilled about every 2 years but not planted (T) or adjacent lands tilled and planted with wheat and lentil (P). Three samples were taken from the depths of 0-20 and 20-40 cm each site. Soil organic carbon (SOC), pH ,electrical conductivity, water soluble Ca(++), Mg(++), CO₃⁻² and HCO₃⁻, extractable potassium (K(+)) and sodium (Na(+)), soil texture, ammonium (NH₄⁺-N) and nitrate (NO(3)-N), extractable phosphorous and soil aggregate stability were determined. While the SOC contents of continuous tillage without cropping and continuous tillage and cropping were 2.2 and 11.6 g kg(-1), respectively, it was 30 g kg(-1) in non-tilled and non-planted site. Tillage of soil without the input of any plant material resulted in loss of carbon from the soil in all sites. Soil extractable NO(3)-N contents of non-tilled and non-cropped sites were greatest among all treatments. Agricultural practices increased phosphorus and potassium contents in the soil profile. P(2)O(5

  9. Nitrate attenuation in agricultural catchments: Shifting balances between transport and reaction

    NASA Astrophysics Data System (ADS)

    Ocampo, Carlos J.; Oldham, Carolyn E.; Sivapalan, Murugesu

    2006-01-01

    Simultaneous observations, across multiple spatial and temporal scales, are needed to understand the complex interactions between hydrological and biogeochemical processes in catchments and the primary controls on NO3- availability and mobility. This paper addresses these issues by using data collected from a detailed field experiment, carried out on two topographically different hillslopes (one steep and the other flat) located within an agricultural catchment in Western Australia. Continuous hydrometric data and measurements of chemical tracers, geochemical parameters, and NO3- concentrations taken from the shallow perched aquifer across riparian, midslope, and upland locations were analyzed and interpreted through a simple process-based numerical model of transport and reaction. The NO3- concentration data indicated that the temporal and spatial patterns of NO3- concentrations within the hillslopes are linked to the state of hydrological connectivity of the three landscape units as the shallow perched aquifer developed during the winter. Significant NO3- attenuation occurs within the riparian zones after the transport of NO3- from midslope sources begins. Application of a mixing model, which partitions the riparian zones into three water source components, and the numerical model of NO3- transport and reaction indicates that different mechanisms, dilution in the steep hillslope and denitrification in the flat hillslope, are responsible for much of the observed NO3- attenuation in the riparian zones. In this way, this work highlights the importance of hillslope topography in determining the relative roles of transport and reaction in NO3- attenuation and export from riparian zones. The experimental results also supported the use of the Damköhler number, a simple dimensionless number that is a measure of the competition between transport and reaction processes, which allowed a favorable comparison of our findings with previous results published in the literature

  10. 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)

  11. 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.

  12. Organochlorine Pesticide Residues in Plankton, Rangsit Agricultural Area, Central Thailand

    PubMed Central

    Siriwong, W.; Thirakhupt, K.; Sitticharoenchai, D.; Borjan, M.; Robson, M.

    2014-01-01

    Few studies have investigated organochlorine pesticide residue content in freshwater plankton communities in Thailand. As a result, this study looks to examine the concentration of organochlorine pesticide residues in plankton collected from Khlong 7 (canal) at Rangsit agricultural area, central Thailand from June 2006 to February 2007. The results from this study show that plankton communities were composed of microphytoplankton, microzooplankton, and mesozooplankton. The average method recoveries varied from 84% to 103% with a relative standard deviation between 0.20% and 3.72%. The concentrations of organochlorine pesticide residues during a one-year-period were in the range of 0.10–3.65 ng/g wet wt and contained DDT and derivatives > Σ endosulfan > Σ HCH > Σ heptachlor > aldrin and dieldrin > endrin and endrin aldehyde > methoxychlor, respectively. Moreover, the residues of Σ HCH, DDT and derivatives, and methoxychlor were higher during wet season than dry season (t-test, p ≤ 0.05). PMID:18777151

  13. 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

  14. Pesticide residues in agricultural drains, southeastern desert area, California

    USGS Publications Warehouse

    Eccles, Lawrence A.

    1979-01-01

    A study is being made to determine the occurrence and distribution of pesticides in the agricultural drains for approximately 3/4 million irrigated acres in the southeastern desert area of California. This report describes the results of the first year of sampling and analyzing (1) water in the drains , (2) bed material in the drains, (3) water from field tile-drainage lines, and (4) irrigation tailwater and water in the drains directly exposed to drift from aerial application of pesticides. Residues of almost all the pesticides selected for monitoring were found in water in the drains. Examination of the data to determine the probable source of pesticides indicated generally slight concentrations from bed material in the drains, usually no detectable concentrations from field tile-drainage lines, and apparently large concentrations from irrigation tailwater and drift from aerial application. (Woodard-USGS)

  15. Organochlorine pesticide residues in plankton, Rangsit agricultural area, central Thailand.

    PubMed

    Siriwong, W; Thirakhupt, K; Sitticharoenchai, D; Borjan, M; Robson, M

    2008-12-01

    Few studies have investigated organochlorine pesticide residue content in freshwater plankton communities in Thailand. As a result, this study looks to examine the concentration of organochlorine pesticide residues in plankton collected from Khlong 7 (canal) at Rangsit agricultural area, central Thailand from June 2006 to February 2007. The results from this study show that plankton communities were composed of microphytoplankton, microzooplankton, and mesozooplankton. The average method recoveries varied from 84% to 103% with a relative standard deviation between 0.20% and 3.72%. The concentrations of organochlorine pesticide residues during a one-year-period were in the range of 0.10-3.65 ng/g wet wt and contained DDT and derivatives > Sigma endosulfan > Sigma HCH > Sigma heptachlor > aldrin and dieldrin > endrin and endrin aldehyde > methoxychlor, respectively. Moreover, the residues of Sigma HCH, DDT and derivatives, and methoxychlor were higher during wet season than dry season (t-test, p

  16. Nitrogen cycling in the Southern Ocean Kerguelen Plateau area: evidence for significant surface nitrification from nitrate isotopic compositions

    NASA Astrophysics Data System (ADS)

    Dehairs, F.; Fripiat, F.; Cavagna, A.-J.; Trull, T. W.; Fernandez, C.; Davies, D.; Roukaerts, A.; Fonseca Batista, D.; Planchon, F.; Elskens, M.

    2015-03-01

    This paper presents whole water column data for nitrate N, O isotopic composition for the Kerguelen Plateau area and the basin extending east of Heard Island, aiming at understanding the N-cycling in this naturally iron fertilized area that is characterized by large re-current phytoplankton blooms. The KEOPS 2 expedition (October-November 2011) took place in spring season and complements knowledge gathered during an earlier summer expedition to the same area (KEOPS 1, February-March 2005). As noted by others a remarkable condition of the system is the moderate consumption of nitrate over the season (nitrate remains >20 μM) while silicic acid becomes depleted, suggesting significant recycling of nitrogen. Nitrate isotopic signatures in the upper water column do mimic this condition, with surprising overlap of spring and summer regressions of δ18ONO3 vs. δ15NNO3 isotopic compositions. These regressions obey rather closely the 18ϵ/15ϵ discrimination expected for nitrate uptake (18ϵ/15ϵ = 1), but regression slopes as large as 1.6 were observed for the mixed layer above the Kerguelen Plateau. A preliminarily mass balance calculation for the early bloom period points toward significant nitrification occurring in the mixed layer and which may be equivalent to up to 47% of nitrate uptake above the Kerguelen Plateau. A further finding concerns deep ocean low δ18ONO3 values (<2‰) underlying high chlorophyll waters at the Polar Front Zone and which cannot be explained by remineralization and nitrification of the local particulate nitrogen flux, which is too small in magnitude. However, the studied area is characterized by a complex recirculation pattern that would keep deep waters in the area and could impose a seasonally integrated signature of surface water processes on the deep waters.

  17. Nitrogen cycling in the Southern Ocean Kerguelen Plateau area: evidence for significant surface nitrification from nitrate isotopic compositions

    NASA Astrophysics Data System (ADS)

    Dehairs, F.; Fripiat, F.; Cavagna, A.-J.; Trull, T. W.; Fernandez, C.; Davies, D.; Roukaerts, A.; Fonseca Batista, D.; Planchon, F.; Elskens, M.

    2014-09-01

    This paper presents whole water column data for nitrate N, O isotopic composition for the Kerguelen Plateau area and the basin extending east of the island, aiming at understanding the N-cycling in this naturally iron fertilized area that is characterized by large re-current phytoplankton blooms. The KEOPS 2 expedition (October-November 2011) took place in spring season and complements knowledge gathered during an earlier summer expedition to the same area (KEOPS 1, February-March 2005). As noted by others a remarkable condition of the system is the moderate consumption of nitrate over the season (nitrate remains > 20 μM) while silicic acid becomes depleted, suggesting significant recycling of nitrogen. Nitrate isotopic signatures in the upper water column do mimic this condition, with surprising overlap of spring and summer regressions of δ18ONO3 vs. δ15NNO3 isotopic compositions. These regressions obey rather closely the 18ϵ/15ϵ discrimination expected for nitrate uptake (18ϵ/15ϵ = 1), but regression slopes as large as 1.6 were observed for the mixed layer above the Kerguelen Plateau. A preliminary mass balance calculation for the early bloom period points toward significant nitrification occurring in the mixed layer and which could account for up to 80 % of nitrate uptake above the Kerguelen Plateau. A further finding concerns deep ocean low δ18ONO3 values (< 2‰) underlying high chlorophyll waters at the Polar Front Zone and which cannot be explained by remineralisation and nitrification of the local particulate nitrogen flux, which is too small in magnitude. However, the studied area is characterised by a complex recirculation pattern that would keep deep waters in the area and could impose a seasonally integrated signature of surface water processes on the deep waters.

  18. 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

  19. Results of nitrate sampling in the Torrington, Wyoming, Wellhead Protection Area, 1994-98

    USGS Publications Warehouse

    Eddy-Miller, C. A.; Gerhard, Gary

    1999-01-01

    A monitoring program for nitrate in ground water in and near Torrington, Wyoming was conducted by the Town of Torrington from April 1994 through March 1997, and cooperatively by the Town of Torrington and the U.S. Geological Survey from May 1997 through August 1998. Trends in nitrate concentrations were determined for the period of time covered by both monitoring programs. A significant trend was detected at 34 of the 72 sites. Twenty-six sites had nitrate concentrations that were increasing, and eight sites had nitrate concentrations that were decreasing. Nitrogen isotope data were also collected at selected sites. These data indicate that the source of nitrate in ground water in and around Torrington is probably not from human or animal waste, but rather organic soil nitrogen, or ammonium or nitrate fertilizer.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. Vertical Sampling in Recharge Areas Versus Lateral Sampling in Discharge Areas: Assessing the Agricultural Nitrogen Legacy in Groundwater

    NASA Astrophysics Data System (ADS)

    Gilmore, T. E.; Genereux, D. P.; Solomon, D. K.; Mitasova, H.; Burnette, M.

    2014-12-01

    Agricultural nitrogen (N) is a legacy contaminant often found in shallow groundwater systems. This legacy has commonly been observed using well nests (vertical sampling) in recharge areas, but may also be observed by sampling at points in/beneath a streambed using pushable probes along transects across a channel (lateral sampling). We compared results from two different streambed point sampling approaches and from wells in the recharge area to assess whether the different approaches give fundamentally different pictures of (1) the magnitude of N contamination, (2) historic trends in N contamination, and (3) the extent to which denitrification attenuates nitrate transport through the surficial aquifer. Two different arrangements of streambed points (SP) were used to sample groundwater discharging into a coastal plain stream in North Carolina. In July 2012, a 58 m reach was sampled using closely-spaced lateral transects of SP, revealing high average [NO3-] (808 μM, n=39). In March 2013, transects of SP were widely distributed through a 2.7 km reach that contained the 58 m reach and suggested overall lower [NO3-] (210 μM, n=30), possibly due to variation in land use along the longer study reach. Mean [NO3-] from vertical sampling (2 well nests with 3 wells each) was 296 μM. Groundwater apparent ages from SP in the 58 m and 2.7 km reaches suggested lower recharge [NO3-] (observed [NO3-] plus modeled excess N2) in 0-10 year-old water (1250 μM and 525 μM, respectively), compared to higher recharge [NO3-] from 10-30 years ago (about 1600 μM and 900 μM, respectively). In the wells, [NO3-] was highest (835 μM) in groundwater with apparent age of 12-15 years and declined as apparent age increased, a trend that was consistent with SP in the 2.7 km reach. The 58 m reach suggested elevated recharge [NO3-] (>1100 μM) over a 50-year period. Excess N2 from wells suggested that about 62% of nitrate had been removed via denitrification since recharge, versus 51% and 78

  5. 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.

  6. 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...

  7. Organic matter and soil structure in the Everglades Agricultural Area

    SciTech Connect

    Wright, Alan L.; Hanlon, Edward A.

    2013-01-01

    This publication pertains to management of organic soils (Histosols) in the Everglades Agricultural Area (EAA). These former wetland soils are a major resource for efficient agricultural production and are important globally for their high organic matter content. Recognition of global warming has led to considerable interest in soils as a repository for carbon. Soils rich in organic matter essentially sequester or retain carbon in the profile and can contribute directly to keeping that sequestered carbon from entering the atmosphere. Identification and utilization of management practices that minimize the loss of carbon from organic soils to the atmosphere can minimize effects on global warming and increase the longevity of subsiding Histosols for agricultural use. Understanding and predicting how these muck soils will respond to current and changing land uses will help to manage soil carbon. The objectives of this document are to: a. Discuss organic soil oxidation relative to storing or releasing carbon and nitrogen b. Evaluate effects of cultivation (compare structure for sugarcane vs. uncultivated soil) Based upon the findings from the land-use comparison (sugarcane or uncultivated), organic carbon was higher with cultivation in the lower depths. There is considerable potential for minimum tillage and residue management to further enhance carbon sequestration in the sugarcane system. Carbon sequestration is improved and soil subsidence is slowed with sugarcane production, and both of these are positive outcomes. Taking action to increase or maintain carbon sequestration appears to be appropriate but may introduce some risk to farming operations. Additional management methods are needed to reduce this risk. For both the longevity of these organic soils and from a global perspective, slowing subsidence through BMP implementation makes sense. Since these BMPs also have considerable societal benefit, it remains to be seen if society will help to offset a part or all

  8. 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.

  9. Nitrate distributions and source identification in the Abbotsford-Sumas Aquifer, northwestern Washington State

    USGS Publications Warehouse

    Mitchell, R.J.; Babcock, R.S.; Gelinas, S.; Nanus, L.; Stasney, D.E.

    2003-01-01

    The Abbotsford-Sumas Aquifer is a shallow, predominantly unconfined aquifer that spans regions in southwestern British Columbia, Canada and northwestern Washington, USA. The aquifer is prone to nitrate contamination because of extensive regional agricultural practices. A 22-month ground water nitrate assessment was performed in a 10-km2 study area adjacent to the international boundary in northwestern Washington to examine nitrate concentrations and nitrogen isotope ratios to characterize local source contributions from up-gradient sources in Canada. Nitrate concentrations in excess of 10 mg nitrate as nitrogen per liter (mg N L-1) were observed in ground water from most of the 26 domestic wells sampled in the study area, and in a creek that dissects the study area. The nitrate distribution was characteristic of nonpoint agricultural sources and consistent with the historical documentation of agriculturally related nitrate contamination in many parts of the aquifer. Hydrogeologic information, nitrogen isotope values, and statistical analyses indicated a nitrate concentration stratification in the study area. The highest concentrations (>20 mg N L-1) occurred in shallow regions of the aquifer and were linked to local agricultural practices in northwestern Washington. Nitrate concentrations in excess of 10 mg N L-1 deeper in the aquifer (>10 m) were related to agricultural sources in Canada. The identification of two possible sources of ground water nitrate in northwestern Washington adds to the difficulty in assessing and implementing local nutrient management plans for protecting drinking water in the region.

  10. 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

  11. 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.

  12. 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…

  13. 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

  14. 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.

  15. 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

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Food and agricultural sciences areas targeted for... AGRICULTURE FOOD AND AGRICULTURAL SCIENCES NATIONAL NEEDS GRADUATE AND POSTGRADUATE FELLOWSHIP GRANTS PROGRAM Program Description § 3402.4 Food and agricultural sciences areas targeted for National Needs Graduate...

  16. 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

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Food and agricultural sciences areas targeted for... AGRICULTURE FOOD AND AGRICULTURAL SCIENCES NATIONAL NEEDS GRADUATE AND POSTGRADUATE FELLOWSHIP GRANTS PROGRAM Program Description § 3402.4 Food and agricultural sciences areas targeted for National Needs Graduate...

  17. 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

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Food and agricultural sciences areas targeted for... AGRICULTURE FOOD AND AGRICULTURAL SCIENCES NATIONAL NEEDS GRADUATE AND POSTGRADUATE FELLOWSHIP GRANTS PROGRAM Program Description § 3402.4 Food and agricultural sciences areas targeted for National Needs Graduate...

  18. 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

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Food and agricultural sciences areas targeted for... AGRICULTURE FOOD AND AGRICULTURAL SCIENCES NATIONAL NEEDS GRADUATE AND POSTGRADUATE FELLOWSHIP GRANTS PROGRAM Program Description § 3402.4 Food and agricultural sciences areas targeted for National Needs Graduate...

  19. 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

  20. Integrating contributing areas and indexing phosphorus loss from agricultural watersheds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most states in the U.S. have adopted P Indexing to guide P-based management of agricultural fields by identifying the relative risk of P loss at farm and watershed scales. To a large extent, this risk is based on hydrologic principles whereby frequently occurring storms have a given potential to in...

  1. 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 (...

  2. 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.

  3. 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...

  4. 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.

  5. Agriculture

    EPA Pesticide Factsheets

    The EPA Agriculture Resource Directory offers comprehensive, easy-to-understand information about environmental stewardship on farms and ranches; commonsense, flexible approaches that are both environmentally protective and agriculturally sound.

  6. 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.

  7. Agrochemical fate models applied in agricultural areas from Colombia

    NASA Astrophysics Data System (ADS)

    Garcia-Santos, Glenda; Yang, Jing; Andreoli, Romano; Binder, Claudia

    2010-05-01

    The misuse application of pesticides in mainly agricultural catchments can lead to severe problems for humans and environment. Especially in developing countries where there is often found overuse of agrochemicals and incipient or lack of water quality monitoring at local and regional levels, models are needed for decision making and hot spots identification. However, the complexity of the water cycle contrasts strongly with the scarce data availability, limiting the number of analysis, techniques, and models available to researchers. Therefore there is a strong need for model simplification able to appropriate model complexity and still represent the processes. We have developed a new model so-called Westpa-Pest to improve water quality management of an agricultural catchment located in the highlands of Colombia. Westpa-Pest is based on the fully distributed hydrologic model Wetspa and a fate pesticide module. We have applied a multi-criteria analysis for model selection under the conditions and data availability found in the region and compared with the new developed Westpa-Pest model. Furthermore, both models were empirically calibrated and validated. The following questions were addressed i) what are the strengths and weaknesses of the models?, ii) which are the most sensitive parameters of each model?, iii) what happens with uncertainties in soil parameters?, and iv) how sensitive are the transfer coefficients?

  8. 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…

  9. 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.

  10. 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

  11. 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.

  12. 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..., AND EXTENSION SERVICE, DEPARTMENT OF AGRICULTURE FOOD AND AGRICULTURAL SCIENCES NATIONAL NEEDS... sciences areas targeted for National Needs Graduate and Postdoctoral Fellowship Grants Program...

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

    NASA Technical Reports Server (NTRS)

    Frazee, C. J.; Myers, V. I.; Westin, F. C.

    1971-01-01

    Research was initiated to establish remote sensing techniques for recognizing and mapping soil limitations to land use. Analysis of soils with limitations to land use because of dense subsoil (claypan) and unfavorable topography (convex sloping or depressional areas) was accomplished by experienced soil scientists utilizing a density slicing system. Maps of soil limitations were produced by photographing the color encoded density slicing analysis of an area. The percentage of each soil limitation was measured by the planimeter feature of the density slicing system. The initial results indicate that a density slicing system has great potential not only for delineating areas of similar soil limitations but also for indicating the percentage composition of an area.

  14. Agricultural practices and personal hygiene among agricultural workers in a rural area of Howrah district, West Bengal.

    PubMed

    Das, D K; Dey, T K

    2005-01-01

    The study attempted to assess agricultural practices and personal hygiene among 100 agricultural workers in a rural area of West Bengal in 1999. 69% of the study population was marginal farmer with less than 2 acres of land. Organophosphorus group of pesticides were most commonly used pesticides (68%); spraying was irregular in nature (98%), through semiautomatic sprayer (99%) and only 5% used any special dress while spraying pesticides. 40% of workers used to store pesticides either in living room or in food storage area. 88% of them did not take any food during work with pesticides, only 37% used to take regular bath after working with pesticides but regular hand washing was practiced by all of them.

  15. 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.

  16. 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

  17. Iron enrichment stimulates toxic diatom production in high-nitrate, low-chlorophyll areas

    PubMed Central

    Trick, Charles G.; Bill, Brian D.; Cochlan, William P.; Wells, Mark L.; Trainer, Vera L.; Pickell, Lisa D.

    2010-01-01

    Oceanic high-nitrate, low-chlorophyll environments have been highlighted for potential large-scale iron fertilizations to help mitigate global climate change. Controversy surrounds these initiatives, both in the degree of carbon removal and magnitude of ecosystem impacts. Previous open ocean enrichment experiments have shown that iron additions stimulate growth of the toxigenic diatom genus Pseudonitzschia. Most Pseudonitzschia species in coastal waters produce the neurotoxin domoic acid (DA), with their blooms causing detrimental marine ecosystem impacts, but oceanic Pseudonitzschia species are considered nontoxic. Here we demonstrate that the sparse oceanic Pseudonitzschia community at the high-nitrate, low-chlorophyll Ocean Station PAPA (50° N, 145° W) produces approximately 200 pg DA L−1 in response to iron addition, that DA alters phytoplankton community structure to benefit Pseudonitzschia, and that oceanic cell isolates are toxic. Given the negative effects of DA in coastal food webs, these findings raise serious concern over the net benefit and sustainability of large-scale iron fertilizations. PMID:20231473

  18. Iron enrichment stimulates toxic diatom production in high-nitrate, low-chlorophyll areas.

    PubMed

    Trick, Charles G; Bill, Brian D; Cochlan, William P; Wells, Mark L; Trainer, Vera L; Pickell, Lisa D

    2010-03-30

    Oceanic high-nitrate, low-chlorophyll environments have been highlighted for potential large-scale iron fertilizations to help mitigate global climate change. Controversy surrounds these initiatives, both in the degree of carbon removal and magnitude of ecosystem impacts. Previous open ocean enrichment experiments have shown that iron additions stimulate growth of the toxigenic diatom genus Pseudonitzschia. Most Pseudonitzschia species in coastal waters produce the neurotoxin domoic acid (DA), with their blooms causing detrimental marine ecosystem impacts, but oceanic Pseudonitzschia species are considered nontoxic. Here we demonstrate that the sparse oceanic Pseudonitzschia community at the high-nitrate, low-chlorophyll Ocean Station PAPA (50 degrees N, 145 degrees W) produces approximately 200 pg DA L(-1) in response to iron addition, that DA alters phytoplankton community structure to benefit Pseudonitzschia, and that oceanic cell isolates are toxic. Given the negative effects of DA in coastal food webs, these findings raise serious concern over the net benefit and sustainability of large-scale iron fertilizations.

  19. 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

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

    PubMed

    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.

  1. 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.

  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. 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...

  4. 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...

  5. 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.

  6. 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

  7. 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.

  8. Phosphorus losses from agricultural areas in river basins: effects and uncertainties of targeted mitigation measures.

    PubMed

    Kronvang, B; Bechmann, M; Lundekvam, H; Behrendt, H; Rubaek, G H; Schoumans, O F; Syversen, N; Andersen, H E; Hoffmann, C C

    2005-01-01

    In this paper we show the quantitative and relative importance of phosphorus (P) losses from agricultural areas within European river basins and demonstrate the importance of P pathways, linking agricultural source areas to surface water at different scales. Agricultural P losses are increasingly important for the P concentration in most European rivers, lakes, and estuaries, even though the quantity of P lost from agricultural areas in European catchments varies at least one order of magnitude (<0.2 kg P ha(-1) to >2.1 kg P ha(-1)). We focus on the importance of P for the implementation of the EU Water Framework Directive and discuss the benefits, uncertainties, and side effects of the different targeted mitigation measures that can be adopted to combat P losses from agricultural areas in river basins. Experimental evidence of the effects of some of the main targeted mitigation measures hitherto implemented is demonstrated, including: (i) soil tillage changes, (ii) treatment of soils near ditches and streams with iron to reduce P transport from source areas to surface waters, (iii) establishment of buffer zones for retaining P from surface runoff, (iv) restoration of river-floodplain systems to allow natural inundation of riparian areas and deposition of P, and (v) inundation of riparian areas with tile drainage water for P retention. Furthermore, we show how river basin managers can map and analyze the extent and importance of P risk areas, exemplified by four catchments differing in size in Norway, Denmark, and the Netherlands. Finally, we discuss the factors and mechanisms that may delay and/or counteract the responses of mitigation measures for combating P losses from agricultural areas when monitored at the catchment scale.

  9. 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.

  10. 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...

  11. Nitrate removal by a paired electrolysis on copper and Ti/IrO(2) coupled electrodes - influence of the anode/cathode surface area ratio.

    PubMed

    Reyter, David; Bélanger, Daniel; Roué, Lionel

    2010-03-01

    In this study, nitrate removal in alkaline media by a paired electrolysis with copper cathode and Ti/IrO(2) anode enabled the conversion of nitrate to nitrogen. Optimum conditions for carrying out reduction of nitrate to ammonia and subsequent oxidation of the produced ammonia to nitrogen were found. At the copper cathode, electroreduction of nitrate to ammonia was optimal near -1.4 V vs Hg/HgO. At the Ti/IrO(2) anode, a pH value of 12, the presence of chloride and a potential fixed around 2.3 V vs Hg/HgO permitted the production of hypochlorite, leading to the oxidation of ammonia to nitrogen with a N(2) selectivity of 100%. Controlling the cathode/anode surface area ratio, and thus the current density, appeared to be a very efficient way of shifting electrode potentials to optimal values, consequently favoring the conversion of nitrate to nitrogen during a paired galvanostatic electrolysis. A cathode/anode surface area ratio of 2.25 was shown to be the most efficient to convert nitrate to nitrogen.

  12. Reconstructing long-term gully dynamics in Mediterranean agricultural areas

    NASA Astrophysics Data System (ADS)

    Hayas, Antonio; Vanwalleghem, Tom; Laguna, Ana; Peña, Adolfo; Giráldez, Juan V.

    2017-01-01

    Gully erosion is an important erosive process in Mediterranean basins. However, the long-term dynamics of gully networks and the variations in sediment production in gullies are not well known. Available studies are often conducted only over a few years, while many gully networks form, grow, and change in response to environmental and land use or management changes over a long period. In order to clarify the effect of these changes, it is important to analyse the evolution of the gully network with a high temporal resolution. This study aims at analysing gully morphodynamics over a long timescale (1956-2013) in a large Mediterranean area in order to quantify gully erosion processes and their contribution to overall sediment dynamics. A gully network of 20 km2 located in southwestern Spain has been analysed using a sequence of 10 aerial photographs in the period 1956-2013. The extension of the gully network both increased and decreased in the study period. Gully drainage density varied between 1.93 km km-2 in 1956, a minimum of 1.37 km km-2 in 1980, and a maximum of 5.40 km km-2 in 2013. The main controlling factor of gully activity appeared to be rainfall. Land use changes were found to have only a secondary effect. A new Monte Carlo-based approach was proposed to reconstruct gully erosion rates from orthophotos. Gully erosion rates were found to be relatively stable between 1956 and 2009, with a mean value of 11.2 t ha-1 yr-1. In the period 2009-2011, characterized by severe winter rainfalls, this value increased significantly to 591 t ha-1 yr-1. These results show that gully erosion rates are highly variable and that a simple interpolation between the starting and ending dates greatly underestimates gully contribution during certain years, such as, for example, between 2009 and 2011. This illustrates the importance of the methodology applied using a high temporal resolution of orthophotos.

  13. [Identification of critical area of phosphorus loss in agricultural areas of Guishui River watershed by phosphorus loss risk assessment].

    PubMed

    Li, Qi; Chen, Li-Ding; Qi, Xin; Zhang, Xin-Yu; Ma, Yan

    2008-01-01

    Agricultural non-point sources pollution is one of severe problems for water environment of agricultural areas in China. Because of the big difficulties, identifying the critical source areas for phosphorus loss becomes the focal point of the non-point sources pollution control. A modified catchment scale phosphorus ranking scheme was developed for agricultural areas in Guishui River watershed. The new scheme included eight assessment factors, which had three phosphorus loss risk ranks respectively and selected quantitative analysis method. The result shows that the phosphorus fertilizer management of the vegetable fields is the most unfit method and has high phosphorus loss probabilities. Most study areas have high soil available phosphorus content and low soil erosion degree. The figure of the assessment result shows that the areas that are categorized as "low" phosphorus loss risk are small. Based on the figure of the result, the critical source areas were confirmed and the management strategies were brought forward according to the analysis on the distribute characteristics of the critical source areas. The result shows that the modified catchment scale phosphorus ranking scheme has operability and practicability to a certain extent.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. Pesticides residues and metals in plant products from agricultural area of Belgrade, Serbia.

    PubMed

    Ethorđević, Tijana; Ethurović, Rada

    2012-03-01

    The objective of study was to assess the levels of selected metals and pesticides in plant products from agricultural area of Belgrade, Serbia in order to indicate their possible sources and risks of contamination and to evaluate their sanitary probity and safety. The concentrations of cadmium, copper, iron, manganese, nickel, lead and zinc were below limits established by national and international regulations (maximum found concentrations were 0.028, 1.91, 11.16, 1.77, 0.605, 0.073 and 1.76 mg kg(-1) respectively). Only residue of one of examined pesticides was found in amount below MRL (bifenthrin 2.46 μg kg(-1)) in only one of analysed samples, while others were below detection limits. Obtained results indicate that crops from examined agricultural areas are unpolluted by contaminants used for plant protection and nutrition, indicating good agricultural practice regarding pesticides and fertilizer usage as well as moderate industrial production within examined areas.

  20. 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.

  1. Map Analysis and Spatial Statistic: Assessment of Spatial Variability of Agriculture Land Conversion at Urban Fringe Area of Yogyakarta

    NASA Astrophysics Data System (ADS)

    Susilo, Bowo

    2016-11-01

    Urban development has brought various effects, one of which was the marginalization of the agricultural sector. Agricultural land is gradually converted to other type of land uses which considered more profitable. Conversion of agricultural land cannot be avoided but it should be controlled. Early identification on spatial distribution and intensity of agricultural land conversion as well as its related factor is necessary. Objective of the research were (1) to assess the spatial variability of agricultural land conversion, (2) to identify factors that affecting the spatial variability of agricultural land conversion. Research was conducted at urban fringe area of Yogyakarta. Spatial variability of agricultural land conversion was analysed using an index called Relative Conversion Index (RCI). Combined of map analysis and spatial statistical were used to determine the center of agricultural land conversion. Simple regression analysis was used to determine the factors associated with the conversion of agricultural land. The result shows that intensity of agricultural land conversion in the study area varies spatially as well as temporally. Intensity of agricultural land conversion in the period 1993-2000, involves three categories which are high, moderate and low. In the period of 2000-2007, the intensity of agricultural land conversion involves two categories which are high and low. Spatial variability of agricultural land conversion in the study area has a significant correlation with three factors: population growth, fragmentation of agricultural land and distance of agricultural land to the city

  2. 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.

  3. 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.

  4. Organic textile waste as a resource for sustainable agriculture in arid and semi-arid areas.

    PubMed

    Eriksson, Bo G

    2017-03-01

    New vegetation in barren areas offers possibilities for sequestering carbon in the soil. Arid and semi-arid areas (ASAs) are candidates for new vegetation. The possibility of agriculture in ASAs is reviewed, revealing the potential for cultivation by covering the surface with a layer of organic fibres. This layer collects more water from humidity in the air than does the uncovered mineral surface, and creates a humid environment that promotes microbial life. One possibility is to use large amounts of organic fibres for soil enhancement in ASAs. In the context of the European Commission Waste Framework Directive, the possibility of using textile waste from Sweden is explored. The costs for using Swedish textile waste are high, but possible gains are the sale of agricultural products and increased land prices as well as environmental mitigation. The findings suggest that field research on such agriculture in ASAs should start as soon as possible.

  5. 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

  6. 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...

  7. Protected areas as biodiversity benchmarks for human impact: agriculture and the Serengeti avifauna.

    PubMed

    Sinclair, A R E; Mduma, Simon A R; Arcese, Peter

    2002-12-07

    Protected areas as biodiversity benchmarks allow a separation of the direct effects of human impact on biodiversity loss from those of other environmental changes. We illustrate the use of ecological baselines with a case from the Serengeti ecosystem, Tanzania. We document a substantial but previously unnoted loss of bird diversity in agriculture detected by reference to the immediately adjacent native vegetation in Serengeti. The abundance of species found in agriculture was only 28% of that for the same species in native savannah. Insectivorous species feeding in the grass layer or in trees were the most reduced. Some 50% of both insectivorous and granivorous species were not recorded in agriculture, with ground-feeding and tree species most affected. Grass-layer insect abundance and diversity was much reduced in agriculture, consistent with the loss of insectivorous birds. These results indicate that many species of birds will become confined to protected areas over time. We need to determine whether existing protected areas are sufficiently large to maintain viable populations of insectivorous birds likely to become confined to them. This study highlights the essential nature of baseline areas for assessing causes of change in human-dominated systems and for developing innovative strategies to restore biodiversity.

  8. 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…

  9. 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

  10. Association between gastric cancer mortality and nitrate content of drinking water: ecological study on small area inequalities.

    PubMed

    Sandor, J; Kiss, I; Farkas, O; Ember, I

    2001-01-01

    The carcinogenic feature of N-nitroso compounds has been well established. Similarly, the transformation of ingested nitrate to N-nitroso compounds in the stomach has been thoroughly documented, nevertheless nitrates' carcinogenic effect has not been proved convincingly in human. The present study was aimed to investigate a population of small villages provided by drinking water with high and widely variable nitrate content (72 mg/l median, 290.7 mg/l 95-percentile concentration). Empirical Bayes estimates for settlement-specific age-, sex-, and year-standardised mortality ratios of gastric cancer (GC) were related to the settlement level average nitrate concentrations in drinking water controlling for confounding effects of smoking, ethnicity and education. The log-transformed average nitrate concentration showed significant positive association with stomach cancer mortality in linear regression analysis (p = 0.014). The settlements were aggregated according to the nitrate concentration into 10-percentile groups and the standardised mortality ratios (SMRs) were calculated. Those groups with higher than 88 mg/l average nitrate concentration showed substantial risk elevation and the log-transformed exposure variables proved to be significant predictors of mortality (p = 0.032) at this level of aggregation also. The association seemed to be fairly strong (r2 = 0.46). Although this investigation constituting an ecological study has certain limitations, it supports the hypothesis that the high level of nitrate in drinking water is involved in the development of GC.

  11. Areas of increasing agricultural abandonment overlap the distribution of previously common, currently threatened plant species.

    PubMed

    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.

  12. 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

  13. Soil dioxins levels at agriculture sites and natural preserve areas of Taiwan.

    PubMed

    Jou, Jin-juh; Lin, Kae-Long; Chung, Jen-Chir; Liaw, Shu-Liang

    2007-08-17

    In this study, agriculture soil in Taiwan has been sampled and analyzed to determine the background level of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DF) in the agricultural and nature preserve areas. Another objective is to investigate relationship between soil characteristics and air deposition in Taiwan. The results indicate that in nature preserve areas the topsoil shows an extraordinary profile of PCDD/DF compared to that in the air deposition. The PCDD/DF levels of the low-contaminated agricultural soils are compatible with those of the nature preserves soils. However, in the highly-contaminated agricultural soils, there is an abrupt jump in their concentrations, 10-100 times higher. The overall I-TEQ values of the background topsoils range from 0.101 to 15.2 ng I-TEQ/kg. Near industrial/urban areas in Taiwan the PCDD/DF are slightly higher compared to those in the low concentration group. Typically, the PCDD/DF background values found in this survey fall in the 90% confidence interval and can thus, be deemed the background levels in Taiwan. Ninety-five percent of these data are below the European and American soil standard of 10 ng I-TEQ/kg d.w. The PCDD/DF profile with one neighborhood soil sample was shown no significant difference.

  14. [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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. [Atmospheric dry and wet nitrogen deposition in typical agricultural areas of North Shaanxi].

    PubMed

    Wei, Yang; Tong, Yan-An; Duan, Min; Qiao, Li; Tian, Hong-Wei; Lei, Xiao-Ying; Ma, Wen-Juan

    2010-01-01

    To investigate the farmland soil nitrogen input from atmospheric dry and wet deposition, a 1-year observation was conducted in the Yulin and Luochuan areas of North Shaanxi Province from June 2007 to May 2008. The total inorganic nitrogen (TIN) deposition in Yulin and Luochuan was 22.17 and 16.95 kg x hm(-2) x a(-1), among which, wet deposition accounted for 95.1% and 90.4%, while dry deposition accounted for 4.9% and 9.6%, respectively, illustrating that the nitrogen deposition in both Yulin and Luochuan was mainly come from wet deposition. In the TIN deposition, the amount of nitrate in Yulin and Luochuan was 12.22 and 9.24 kg x hm(-2) xa(-1), accounting for 55.1% and 54.5%, respectively. The amount of wet deposition and the percentage of nitrate in TIN deposition were higher in Yulin than in Luochuan, because of the differences in pollution level, weather condition, and underlying surface characteristics.

  1. [Population dynamics, the development of agricultural systems, and agricultural production in the densely populated rural areas of Cameroon].

    PubMed

    Kelodjoue, S

    1989-06-01

    This comparative examination of changes in agrarian systems in 3 densely populated regions of Cameroon is intended to assess the role of demographic factors in agrarian changes and to permit prediction of future ability of the regions to continue supporting dense populations while providing a surplus for export to the rapidly growing cities. The 3 regions, Bamileke, Mont Mandaras, and the department of Lekie, are characterized by different climatic conditions, vegetation, soil types, and social organization. The total population of the 3 regions has increased from 1,278,644 in 1976 to 1,799,782 in 1987. High fertility rates seem to be the principal factor in this rapid growth. Despite very different systems of land tenure and crop regimes, the 3 areas have in common a serious lack of new lands capable of absorbing their surplus labor, and all have been greatly influenced by the introduction and spread of cash crops as their populations have come to see the land as a producer of income in addition to food, and have attempted to maximize their land holdings in conformity with their available labor and especially their desire for cash. In some areas land is no longer given to young men. Erosion and soil exhaustion are increasing. The spread of cash crops threatens the local food supply, and earnings tend to be invested in housed or wedding ceremonies rather than in increasing production. Population pressure has prompted colonization of new lands and migration to the cities or other rural areas, as well as appropriation of communal lands for private use. Conflicts over land are carried over into other areas of communal life. Underemployment of young men in some areas has led to delinquency. Efforts to intensify land use appear to be successful in the long run only where the soil is rich. Demographic pressure is a factor in the agrarian transformation of these areas, but it is only 1 of a number of factors of which the most important appears to be the entrance of the

  2. 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

  3. 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

  4. 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

  5. Soil organic carbon accumulation during post-agricultural succession in a karst area, southwest China

    PubMed Central

    Yang, Liqiong; Luo, Pan; Wen, Li; Li, Dejun

    2016-01-01

    This study was aimed to investigate the direction and magnitude of soil organic carbon (SOC) dynamics and the underlying mechanisms following agricultural abandonment in a subtropical karst area, southwest China. Two post-agriculture succession sequences including grassland (~10 years), shrubland (~29 years), secondary forest (~59 years) and primary forest with cropland as reference were selected. SOC and other soil physicochemical variables in the soil depth of 0–15 cm (representing the average soil depth of the slope in the studied area) were measured. SOC content in the grassland was not significantly elevated relative to the cropland (42.0 ± 7.3 Mg C ha−1). SOC content in the shrubland reached the level of the primary forest. On average, SOC content for the forest was 92.6 ± 4.2 Mg C ha−1, representing an increase of 120.4 ± 10.0% or 50.6 ± 4.2 Mg ha−1 relative to the cropland. Following agricultural abandonment, SOC recovered to the primary forest level in about 40 years with a rate of 1.38 Mg C ha−1 yr−1. Exchangeable Ca and Mg were found to be the strongest predictors of SOC dynamics. Our results suggest that SOC content may recover rapidly following agricultural abandonment in the karst region of southwest China. PMID:27876827

  6. Soil organic carbon accumulation during post-agricultural succession in a karst area, southwest China.

    PubMed

    Yang, Liqiong; Luo, Pan; Wen, Li; Li, Dejun

    2016-11-23

    This study was aimed to investigate the direction and magnitude of soil organic carbon (SOC) dynamics and the underlying mechanisms following agricultural abandonment in a subtropical karst area, southwest China. Two post-agriculture succession sequences including grassland (~10 years), shrubland (~29 years), secondary forest (~59 years) and primary forest with cropland as reference were selected. SOC and other soil physicochemical variables in the soil depth of 0-15 cm (representing the average soil depth of the slope in the studied area) were measured. SOC content in the grassland was not significantly elevated relative to the cropland (42.0 ± 7.3 Mg C ha(-1)). SOC content in the shrubland reached the level of the primary forest. On average, SOC content for the forest was 92.6 ± 4.2 Mg C ha(-1), representing an increase of 120.4 ± 10.0% or 50.6 ± 4.2 Mg ha(-1) relative to the cropland. Following agricultural abandonment, SOC recovered to the primary forest level in about 40 years with a rate of 1.38 Mg C ha(-1) yr(-1). Exchangeable Ca and Mg were found to be the strongest predictors of SOC dynamics. Our results suggest that SOC content may recover rapidly following agricultural abandonment in the karst region of southwest China.

  7. Soil organic carbon accumulation during post-agricultural succession in a karst area, southwest China

    NASA Astrophysics Data System (ADS)

    Yang, Liqiong; Luo, Pan; Wen, Li; Li, Dejun

    2016-11-01

    This study was aimed to investigate the direction and magnitude of soil organic carbon (SOC) dynamics and the underlying mechanisms following agricultural abandonment in a subtropical karst area, southwest China. Two post-agriculture succession sequences including grassland (~10 years), shrubland (~29 years), secondary forest (~59 years) and primary forest with cropland as reference were selected. SOC and other soil physicochemical variables in the soil depth of 0–15 cm (representing the average soil depth of the slope in the studied area) were measured. SOC content in the grassland was not significantly elevated relative to the cropland (42.0 ± 7.3 Mg C ha‑1). SOC content in the shrubland reached the level of the primary forest. On average, SOC content for the forest was 92.6 ± 4.2 Mg C ha‑1, representing an increase of 120.4 ± 10.0% or 50.6 ± 4.2 Mg ha‑1 relative to the cropland. Following agricultural abandonment, SOC recovered to the primary forest level in about 40 years with a rate of 1.38 Mg C ha‑1 yr‑1. Exchangeable Ca and Mg were found to be the strongest predictors of SOC dynamics. Our results suggest that SOC content may recover rapidly following agricultural abandonment in the karst region of southwest China.

  8. 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.

  9. 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.

  10. Nitrate contamination and its relationship with flood irrigation management

    NASA Astrophysics Data System (ADS)

    García-Garizábal, I.; Causapé, J.; Abrahao, R.

    2012-06-01

    SummaryNitrate contamination is a significant unresolved environmental issue for agriculture in the 21st century, with longstanding challenges in its control and allocation to a specified territory. In order to address these challenges, real-world meticulous irrigation area studies are required. The objective of this investigation is to analyze the evolution of nitrate contamination in relation to agronomic and management changes within a traditionally irrigated land. Specifically, the impact of changes in irrigation allowance assignment, changes in irrigation method from rotation to on-demand flood irrigation, and creation of water consumption accounts were analyzed. To this end, nitrogen monitoring and annual balances were carried out in a small irrigated hydrological basin (95 ha) located in Northeastern Spain throughout the years of 2001 and 2005-2008. The evolution of the nitrate contamination index was also analyzed, which relates the mass of nitrates exported to the fertilization necessities of a specific irrigated area. The results demonstrated that although changes in crop pattern caused a 33% reduction in the nitrogen required through fertilization, the fertilization rates applied are still double the necessities. Changes in irrigation management decreased the mass of nitrates exported by half and the nitrate contamination index by 24%, but the nitrate levels present are still approximately double of those registered in modern irrigation areas. The changes implemented by the Irrigation District in the irrigation management were effective. However, this study confirms that a greater effort is still required to achieve adequate nitrogen fertilization matching the crop necessities.

  11. Sources of Nitrate Contamination in Groundwater Under Developing Asian Megacities

    NASA Astrophysics Data System (ADS)

    Umezawa, Y.; Hosono, T.; Onodera, S.; Siringan, F.; Buapeng, S.; Delinom, R. M.; Yoshimizu, C.; Tayasu, I.; Nagata, T.; Taniguchi, M.

    2008-12-01

    The status of nitrate, nitrite and ammonium contamination in the water systems, and the mechanisms controlling their sources, pathways, and distributions were investigated for the Southeast Asian cities of Metro Manila, Bangkok, and Jakarta. GIS-based monitoring and dual isotope approach (nitrate d15N and d18O) suggested that human waste via severe sewer leakage was the major source of nutrient contaminants in Metro Manila and Jakarta urban areas. Furthermore, the characteristics of the nutrient contamination differed depending on the agricultural land use pattern in the suburban areas. The exponential increase in nitrate d15N along with the nitrate reduction and clear d18O/d15N slopes of nitrate (~0.5) indicated the occurrence of denitrification. An anoxic subsurface system associated with the natural geological setting (e.g., the old tidal plain at Bangkok) and artificial pavement coverage served to buffer nitrate contamination via active denitrification and reduced nitrification. Our results showed that nitrate and ammonium contamination of the aquifers in Metro Manila, Bangkok, and Jakarta was not excessive, suggesting low risk of drinking groundwater to human health, at present. However, the increased nitrogen load and increased per capita gross domestic product (GDP) in these developing cities may increase this contamination in the very near future. Continuous monitoring and management of the groundwater system is needed to minimize groundwater pollution in these areas.

  12. 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.

  13. 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.

  14. Remote sensing for developing world agriculture: opportunities and areas for technical development

    NASA Astrophysics Data System (ADS)

    Jeunnette, Mark N.; Hart, Douglas P.

    2016-10-01

    A parameterized numerical model is constructed to compare platform options for collecting aerial imagery to support agriculture electronic information services in developing countries like India. A sensitivity analysis shows that when Unmanned Aerial Vehicles, UAVs, are limited in flight altitude by regulations, the velocity and altitude available to manned aircraft lead to a lower cost of operation at altitudes greater than 2000ft above ground level, AGL. If, however, the UAVs are allowed to fly higher, they become cost-competitive once again at approximately 1000ft AGL or higher. Examination of assumptions in the model highlights two areas for additional technology development: baseline-dependent feature-based image registration to enable wider area coverage, and reflectance reconstruction for ratio-based agriculture indices.

  15. 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

  16. Combined use of groundwater dating, chemical, and isotopic analyses to resolve the history and fate of nitrate contamination in two agricultural watersheds, Atlantic coastal plain, Maryland

    USGS Publications Warehouse

    Böhlke, J.K.; Denver, J.M.

    1995-01-01

    The history and fate of groundwater nitrate (NO3−) contamination were compared in 2 small adjacent agricultural watersheds in the Atlantic coastal plain by combined use of chronologic (CCl2F2, 3H), chemical (dissolved solids, gases), and isotopic (δ15N,δ13C, δ34S) analyses of recharging groundwaters, discharging groundwaters, and surface waters. The results demonstrate the interactive effects of changing agricultural practices, groundwater residence times, and local geologic features on the transfer of NO3− through local flow systems. Recharge dates of groundwaters taken in 1990–1992 from the surficial aquifer in the Chesterville Branch and Morgan Creek watersheds near Locust Grove, Maryland, ranged from pre-1940 to the late 1980’s. When corrected for localized denitrification by use of dissolved gas concentrations, the dated waters provide a 40-year record of the recharge rate of NO3−, which increased in both watersheds by a factor of 3–6, most rapidly in the 1970's. The increase in groundwater NO3− over time was approximately proportional to the documented increase in regional N fertilizer use, and could be accounted for by oxidation and leaching of about 20–35% of the fertilizer N. Groundwaters discharging upward beneath streams in both watersheds had measured recharge dates from pre-1940 to 1975, while chemical data for second-order reaches of the streams indicated average groundwater residence times in the order of 20+ years. At the time of the study, NO3− discharge rates were less than NO3− recharge rates for at least two reasons: (1) discharge of relatively old waters with low initial NO3− concentrations, and (2) local denitrification. In the Chesterville Branch watershed, groundwaters remained oxic throughout much of the surficial aquifer and discharged relatively unaltered to the stream, which had a relatively high NO3−concentration (9–10 mg/L as N). In the Morgan Creek watershed, groundwaters were largely reduced and

  17. 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.

  18. 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

  19. 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

  20. 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

  1. 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

  2. Nitrate Leaching Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrate (NO3) leaching is a significant nitrogen (N) loss process for agriculture that must be managed to minimize NO3 enrichment of groundwater and surface waters. Managing NO3 leaching should involve the application of basic principles of understanding the site’s hydrologic cycle, avoiding excess ...

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. Assessment of agricultural drought in rainfed cereal production areas of northern China

    NASA Astrophysics Data System (ADS)

    Li, Rui; Tsunekawa, Atsushi; Tsubo, Mitsuru

    2017-02-01

    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.

  8. 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.

  9. 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...

  10. Organochlorine Pesticides in Gonad, Brain, and Blood of Mice in Two Agricultural Areas of Sinaloa.

    PubMed

    Perez-Gonzalez, Ernestina; Osuna-Martinez, Ulises-Giovanni; Herrera-Moreno, Maria-Nancy; Rodriguez-Meza, Guadalupe-Durga; Gonzalez-Ocampo, Hector-A; Bucio-Pacheco, Marcos

    2017-04-01

    The adverse effect of pesticides on non-target wildlife and human health is a primary concern in the world, but in Mexico, we do not know which wildlife species are at the greatest risk. The aim of this study was to determine organochlorine pesticides in mice of two agricultural fields in Sinaloa, Culiacan and Guasave. Procedures of extraction, analysis, and quantification were followed according to the modified EPA 8081b method. In three mouse tissues (gonad, brain, and blood), γBHC and decachlorobiphenyl with a frequency higher than 50% and endosulfan sulfate with 43% were observed. The wildlife fauna living in agricultural areas are at great risk due to: (1) diversity of the chemicals used for pest control, like mice, and (2) variety of organochlorine pesticides in direct or indirect contact with non-target organisms, affecting the health of animals and humans (toxic effects and accumulation).

  11. 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.

  12. 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.

  13. Nitrate tolerance.

    PubMed

    Parker, J O

    1987-11-16

    The organic nitrates are the most widely used agents in the management of patients with angina pectoris. When initially administered by the oral route, the nitrates produce profound changes in systemic hemodynamics and significant and prolonged improvement in exercise duration. It has been shown that during short periods of regular oral nitrate administration, the hemodynamic, antiischemic and antianginal effects of the nitrates are greatly reduced. Thus, when initially administered, oral isosorbide dinitrate prolongs exercise duration for a period of several hours, but during sustained 4-times-daily therapy, exercise tolerance is improved for only 2 hours after administration. Studies with transdermal preparations of isosorbide dinitrate and nitroglycerin also show improvement during short-term administration for up to 8 hours, but after several days of once-daily therapy, the effects of these agents are similar to placebo. It is apparent that nitrate tolerance is a clinically relevant problem. Although tolerance develops rapidly during nitrate therapy, it is reversed promptly during nitrate-free periods. Oral nitrates maintain their antianginal effects when given 2 or 3 times daily with provision of a nitrate-free period. Studies are currently underway to investigate the effects of intermittent administration schedules with transdermal nitrate preparations.

  14. 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.

  15. Protected areas and agricultural expansion: Biodiversity conservation versus economic growth in the Southeast of Brazil.

    PubMed

    Moraes, Mayra Cristina Prado de; Mello, Kaline de; Toppa, Rogério Hartung

    2017-03-01

    The conversion of natural ecosystems to agricultural land and urban areas plays a threat to the protected areas and the natural ecosystems conservation. The aim of this paper is to provide an analysis of the agricultural expansion and its impact on the landscape spatial and temporal patterns in a buffer zone of a protected area located in the transition zone between the Atlantic Forest and Cerrado, in the State of São Paulo, Brazil. The land use and land cover were mapped between 1971 and 2008 and landscape metrics were calculated to provide a spatiotemporal analysis of the forest structure and the expansion of the croplands. The results showed that the landscape patterns were affected by the economic cycles. The predominant crop surrounding the protected area is sugar cane, which increased by 39% during this period, followed by citrus. This landscape change is connected to the Brazilian oil crisis in 1973. The rapid expansion of sugar cane was largely driven by Brazil's biofuel program, the "Proálcool" (pro-alcohol), a project in 1975 that mixed ethanol with gas for automotive fuel. The forest loss occurred mainly between 1971 and 1988, decreasing the forest cover from 17% in 1971 to 12.7% in 2008. Most of the forest patches are smaller than 50 ha and has low connectivity. Throughout the years, the fragments in the buffer zone have become smaller and with an elongated shape, and the park has become isolated. This forest fragmentation process and the predominance of monoculture lands in the buffer zone threaten the protected areas, and can represent a barrier for these areas to provide the effective biodiversity conservation. The measures proposed are necessary to ensure the capability of this ecosystem to sustain its original biodiversity.

  16. 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.

  17. 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.

  18. Modelling of nitrate leaching from arable land into unsaturated soil and chalk 2. Model confirmation and application to agricultural and sewage sludge management

    NASA Astrophysics Data System (ADS)

    Andrews, R. J.; Lloyd, J. W.; Lerner, D. N.

    1997-12-01

    A layered deterministic N-leaching model, IMPACT, has been calibrated using data from two study sites on the unconfined Chalk aquilfer of East Anglia, UK. The model predicts nitrogen species movement resulting from the application of sewage sludges and fertilizers to arable land for different vegetation-soil-hydrogeological conditions. One site received sludge in the form of digested sewage cake (DSC) for the first time during the study period, whilst the other site had over 15 years history of liquid undigested sludge (LUS) applications at 3 year intervals. Site data included: 3-monthly concentration profiles at 0.3 m intervals to depths of up to 6 m for N-species and chloride; unsaturated potential measurements; water level and saturated groundwater solute concentrations, fertilizer and sludge input; daily recharge, and soil/chalk type and moisture content. The observed average movement rate for nitrate peaks in the Lower Chalk, measured at one site, was 0.2 m year -2. Leachate peaks were not observed annually but approximately every third year, being associated with large sludge applications and ploughing of grass crops. Significant correlation between observed and modelled nitrate profiles in soil and chalk were obtained which demonstrated applications. The relationship between crop demand, application times of fertilizers and sludge, nitrate availability and recharge was shown strongly to control the shape of nitrate profiles in the soil and chalk and the quantity of nitrate leached tochalk. The change in hydrogeological conditions at the soil-chalk contact and associated potential for denitrification was also shown to exert a significant control on the shape of the nitrate profile. Following calibration, different arable crop and sludge application regimes were examined for a 6 year period and ranked according to their nitrate leaching risk. Of the modelled cereal farming scenarios, the crop/sludge regime giving the least nitrate leaching was a late autumn

  19. Agricultural runoff fuels large phytoplankton blooms in vulnerable areas of the ocean.

    PubMed

    Michael Beman, J; Arrigo, Kevin R; Matson, Pamela A

    2005-03-10

    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 (54-577 km2) 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. 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.

  1. The Chilean nitrate deposits.

    USGS Publications Warehouse

    Ericksen, G.E.

    1983-01-01

    The nitrate deposits in the arid Atacama desert of northern Chile consist of saline-cemented surficial material, apparently formed in and near a playa lake that formerly covered the area. Many features of their distribution and chemical composition are unique. The author believes the principal sources of the saline constituents were the volcanic rocks of late Tertiary and Quaternary age in the Andes and that the nitrate is of organic origin. Possible sources of the nitrate, iodate, perchlorate and chromate are discussed. -J.J.Robertson

  2. Decadal-scale changes of nitrate in ground water of the United States, 1988-2004

    USGS Publications Warehouse

    Rupert, Michael 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.

  3. Water supply patterns in two agricultural areas of Central Germany under climate change conditions

    NASA Astrophysics Data System (ADS)

    Tölle, M. H.; Moseley, C.; Panferov, O.; Busch, G.; Knohl, A.

    2012-04-01

    Increasing emissions of greenhouse gases and increasing prices for fossil fuels have highlighted the demand for CO2 "neutral" renewable energy sources, e.g. short rotation forestry systems used for bioenergy. These systems might be vulnerable to changes in temperature, precipitation and occurrence of extreme weather events. To estimate success or failure of such short rotation coppices in a certain area we need regional climate projections and risk assessment. Changes of water supply patterns in two agriculturally extensively used regions in Central Germany (around Göttingen and Großfahner) with different climate conditions but both in the temperate climate zone are explored. The study is carried out under present conditions as well as under projected climate change conditions (1971-2100) using A1B and B1 climate scenarios downscaled for Europe. Analysis of precipitation bias shows regional differences: a strong bias in Göttingen area and a weaker bias in the Großfahner area. A bias correction approach, Quantile mapping, is applied to the ensemble results for both areas for winter and summer seasons. By using quantile regression on the seasonal Standardized Precipitation Indices (SPIs) as indicator for water supply conditions we found that precipitation is expected to increase in winter in all quantiles of the distribution for Göttingen area during the 21th century. Heavy precipitation is also expected to increase for Großfahner area suggesting a trend to wetter extremes in winter for the future. This winter precipitation increase could trigger runoff and soil erosion risk enhancing the severity of floods. Increasing winter availability of water could enhance local water supply in spring. For both areas no significant change in summer was found over the whole time period. Although the climate change signal of the SPI indicate mild dryer conditions in summer at the end of the 21st century which may trigger water shortage and summer drying associated with above

  4. 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

  5. Spectral diversity area relationships for assessing biodiversity in a wildland-agriculture matrix.

    PubMed

    Dahlin, Kyla Marie

    2016-12-01

    Species-area relationships have long been used to assess patterns of species diversity across scales. Here, this concept is extended to spectral diversity using hyperspectral data collected by NASA's Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) over western Michigan. This mixture of mesic forest and agricultural lands offers two end-points on the local-scale diversity continuum; one set of well-mixed forest patches and one set of highly homogeneous agricultural patches. Using the sum of the first three principal component values and the principal components' convex hull volume, spectral diversity was compared within and among these plots and to null expectations for perfectly random and perfectly patchy landscapes. Overall, the spectral diversity-area relationship confirms the patterns that would be expected for this landscape, but this application suggests that this approach could be extended to less well-understood landscapes and could reveal key insights about the relative importance of different drivers of community assembly, even in the absence of additional data about plant functional traits or species' identities.

  6. 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).

  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. Assessment of Nitrate Contamination of Groundwater in Korea Using a Mathematical Simulation Model

    NASA Astrophysics Data System (ADS)

    Lee, E.; Kim, M.; Lee, K.

    2005-12-01

    According to the nationwide groundwater monitoring system, nitrate is one of the major contaminants found in groundwater in Korea. Septic systems, animal waste and fertilizer are potential sources of nitrate contamination. There have been a growing number of studies on identification of the source of nitrate contamination of groundwater at agricultural sites, or analysis of the groundwater contamination at intensive livestock facilities. However, there have been a few studies on linkage between the surface loading of nitrate sources and the level of groundwater contamination. The objective of this study is to assess the groundwater contamination with nitrate resulted from current agricultural practices, and the potential impacts of changes in the practices on the groundwater contamination by using a mathematical model. An integrated modeling framework incorporating the nitrogen leaching model, LEACHN, and mass transport model, RT3D linked to MODFLOW was used to account for the fate and transport of nitrate through soil and groundwater. Data were collected from different areas so that they could represent the condition of agricultural sites in Korea. The groundwater nitrate contamination was assessed for different crops and soil types under varying fertilization rates and manure application.

  9. 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.

  10. 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...

  11. Perfluorinated Compounds in Greenhouse and Open Agricultural Producing Areas of Three Provinces of China: Levels, Sources and Risk Assessment

    PubMed Central

    Zhang, Yanwei; Tan, Dongfei; Geng, Yue; Wang, Lu; Peng, Yi; He, Zeying; Xu, Yaping; Liu, Xiaowei

    2016-01-01

    Field investigations on perfluoroalkyl acid (PFAA) levels in various environmental matrixes were reported, but there is still a lack of PFAA level data for agricultural environments, especially agricultural producing areas, so we collected soil, irrigation water and agricultural product samples from agricultural producing areas in the provinces of Liaoning, Shandong and Sichuan in China. The background pollution from instruments was removed and C4–C18 PFAAs were detected by LC-MS/MS. The concentrations of PFAAs in the top and deep layers of soil were compared, and the levels of PFAAs in different agricultural environments (greenhouses and open agriculture) were analyzed. We found the order of PFAA levels by province was Shandong > Liaoning > Sichuan. A descending trend of PFAA levels from top to deep soil and open to greenhouse agriculture was shown and perfluorobutanoic acid (PFBA) was considered as a marker for source analysis. Bean vegetables contribute highly to the overall PFAA load in vegetables. A significant correlation was shown between irrigation water and agricultural products. The EDI (estimated daily intake) from vegetables should be of concern in China. PMID:27973400

  12. 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

  13. Prostate Cancer and Ambient Pesticide Exposure in Agriculturally Intensive Areas in California

    PubMed Central

    Cockburn, Myles; Mills, Paul; Zhang, Xinbo; Zadnick, John; Goldberg, Dan; Ritz, Beate

    2011-01-01

    In a population-based case-control study in California's intensely agricultural Central Valley (2005–2006), the authors investigated relations between environmental pesticide/fungicide exposure and prostate cancer. Cases (n = 173) were obtained from a population-based cancer registry, and controls (n = 162) were obtained from Medicare listings and tax assessor mailings. Past ambient exposures to pesticides/fungicides were derived from residential history and independently recorded pesticide and land-use data, using a novel geographic information systems approach. In comparison with unexposed persons, increased risks of prostate cancer were observed among persons exposed to compounds which may have prostate-specific biologic effects (methyl bromide (odds ratio = 1.62, 95% confidence interval: 1.02, 2.59) and a group of organochlorines (odds ratio = 1.64, 95% confidence interval: 1.02, 2.63)) but not among those exposed to other compounds that were included as controls (simazine, maneb, and paraquat dichloride). The authors assessed the possibility of selection bias due to less-than-100% enrollment of eligible cases and controls (a critical methodological concern in studies of this kind) and determined that there was little evidence of bias affecting the estimated effect size. This study provides evidence of an association between prostate cancer and ambient pesticide exposures in and around homes in intensely agricultural areas. The associations appear specific to compounds with a plausible biologic role in prostate carcinogenesis. PMID:21447478

  14. 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.

  15. 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.

  16. A tiered risk-based approach for predicting diffuse and point source phosphorus losses in agricultural areas.

    PubMed

    Heathwaite, A L; Dils, R M; Liu, S; Carvalho, L; Brazier, R E; Pope, L; Hughes, M; Phillips, G; May, L

    2005-05-15

    %); England the most (88%), with Wales having an intermediate percentage (56%). A comparison of P pressures on freshwaters using the tier 2 approach with other pressures on waterbodies (e.g. nitrate, sediment) in GB is shown as risk maps on the Environment Agency website at: . The tier 3 approach was applied to data-rich catchments and identified at the 1 km(2) areas of relatively high risk of P delivery to water.

  17. Bee honey as an environmental bioindicator of pesticides' occurrence in six agricultural areas of Greece.

    PubMed

    Balayiannis, George; Balayiannis, Panos

    2008-10-01

    The pollution of six agricultural areas of Greece (north, central, south) by insecticides used in crop protection has been investigated utilizing, as a bioindicator, bee honey produced in those areas. Honey samples collected randomly from apiaries located in those areas were analyzed for pesticide residues with a multianalytical method, able to determine simultaneously up to 10 organophosphorous insecticides from the same honey extract. Findings concerning the acaricide coumaphos were also included, even though it is not used in crop protection. Coumaphos is used to control the mite Varroa destructor, an external parasite of the honeybee. The above areas are cultivated in large extent with citrus trees or cotton or sunflower crops, which are good forages for honeybees. The main pests of those crops are insects; hence, insecticides are used on a large scale for crop protection. The most contaminated samples originated from citrus groves; 16 out of 19 had pesticide residues: 4 samples had chlorfenvinphos (21.05%), 10 had chlorpyrifos (52.63%) and 2 had phorate (10.53%). Out of 17 samples from cotton fields, residues were found in 8, phorate in 6 (35.29%), chlorfenvinphos in 1 (5.88%), and chlorpyrifos in 1 (5.88%). Out of nine samples from fields of sunflower, four had phorate residues (44.44%). In brief, from the 50 analyzed samples, residues of chlorfenvinphos were detected in 5 samples (10%), residues of chlorpyrifos in 11 samples (22%), and residues of phorate in 12 samples (24%). Their levels ranged between 0.70 and 0.89 microg/kg. Coumaphos residues ranged from 0.10 up to 4.80 microg/kg and were derived exclusively from beehives treated with Perizin (the commercial formulation of coumaphos) for Varroa control. This study indicates that in agricultural areas with developed apiculture, useful information about the occurrence and the distribution of pesticide residues due to crop protection treatments can be derived from the analysis of randomly collected honey

  18. 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

  19. The burial of headwater streams in drainage pipes reduces in-stream nitrate retention: results from two US metropolitan areas

    NASA Astrophysics Data System (ADS)

    Beaulieu, J. J.; Mayer, P. M.; Kaushal, S.; Pennino, M. J.; Arango, C. P.; Balz, D. A.; Fritz, K. M.; Golden, H. E.; Knightes, C. D.

    2012-12-01

    Nitrogen (N) retention in stream networks is an important ecosystem service that may be affected by the widespread burial of headwater streams in urban watersheds. Stream burial occurs when segments of a channel are encased in drainage pipe and buried beneath the land surface to facilitate above ground development or stormwater runoff. We predicted that burial suppresses the capacity of streams to retain and transform nitrate, the dominate form of bioavailable N in urban streams, by eliminating primary production, reducing respiration rates, and decreasing water residence time. We tested these predictions by measuring whole-stream nitrate (NO3-) removal rates using 15NO3- isotope tracer releases in reaches that were buried and open to the sunlight in three streams in Cincinnati, Ohio and three streams in Baltimore, Maryland during four seasons. Nitrate uptake lengths in buried reaches (range: 560 - 43,650 m) were 2-98 times greater than open reaches exposed to daylight (range: 85 - 7195 m), indicating that buried reaches were substantially less effective at retaining NO3- than open reaches. Nitrate retention in buried reaches was suppressed by a combination of hydrological and biological processes. High water velocities in buried reaches (buried= 5.8 m/s, open=1.48 m/s) rapidly exported NO3- from the channel, reducing the potential for in-stream NO3- retention. Uptake lengths in the buried reaches were lengthened further by low in-stream biological NO3- demand, as indicated by NO3- uptake velocities 16-fold lower than that of the open reaches. Similarly, buried reaches had lower ecosystem respiration rates than open reaches (buried=1.5g O2/m2/hr, open=4.5g O2/m2/hr), likely due to lower organic matter standing stocks (buried=12 gAFMD/m2, open=48 gAFDM/m2). Biological activity in the buried reaches was further suppressed by the absence of light which precluded photosynthetic activity and the associated assimilative N demand. Overall, our results demonstrate that the

  20. Microbial Community of High Arsenic Groundwater in Agricultural Irrigation Area of Hetao Plain, Inner Mongolia.

    PubMed

    Wang, Yanhong; Li, Ping; Jiang, Zhou; Sinkkonen, Aki; Wang, Shi; Tu, Jin; Wei, Dazhun; Dong, Hailiang; Wang, Yanxin

    2016-01-01

    Microbial communities can play important role in arsenic release in groundwater aquifers. To investigate the microbial communities in high arsenic groundwater aquifers in agricultural irrigation area, 17 groundwater samples with different arsenic concentrations were collected along the agricultural drainage channels of Hangjinhouqi County, Inner Mongolia and examined by illumina MiSeq sequencing approach targeting the V4 region of the 16S rRNA genes. Both principal component analysis and hierarchical clustering results indicated that these samples were divided into two groups (high and low arsenic groups) according to the variation of geochemical characteristics. Arsenic concentrations showed strongly positive correlations with [Formula: see text] and total organic carbon (TOC). Sequencing results revealed that a total of 329-2823 operational taxonomic units (OTUs) were observed at the 97% OTU level. Microbial richness and diversity of high arsenic groundwater samples along the drainage channels were lower than those of low arsenic groundwater samples but higher than those of high arsenic groundwaters from strongly reducing areas. The microbial community structure in groundwater along the drainage channels was different from those in strongly reducing arsenic-rich aquifers of Hetao Plain and other high arsenic groundwater aquifers including Bangladesh, West Bengal, and Vietnam. Acinetobacter and Pseudomonas dominated with high percentages in both high and low arsenic groundwaters. Alishewanella, Psychrobacter, Methylotenera, and Crenothrix showed relatively high abundances in high arsenic groundwater, while Rheinheimera and the unidentified OP3 were predominant populations in low arsenic groundwater. Archaeal populations displayed a low occurrence and mainly dominated by methanogens such as Methanocorpusculum and Methanospirillum. Microbial community compositions were different between high and low arsenic groundwater samples based on the results of principal

  1. Microbial Community of High Arsenic Groundwater in Agricultural Irrigation Area of Hetao Plain, Inner Mongolia

    PubMed Central

    Wang, Yanhong; Li, Ping; Jiang, Zhou; Sinkkonen, Aki; Wang, Shi; Tu, Jin; Wei, Dazhun; Dong, Hailiang; Wang, Yanxin

    2016-01-01

    Microbial communities can play important role in arsenic release in groundwater aquifers. To investigate the microbial communities in high arsenic groundwater aquifers in agricultural irrigation area, 17 groundwater samples with different arsenic concentrations were collected along the agricultural drainage channels of Hangjinhouqi County, Inner Mongolia and examined by illumina MiSeq sequencing approach targeting the V4 region of the 16S rRNA genes. Both principal component analysis and hierarchical clustering results indicated that these samples were divided into two groups (high and low arsenic groups) according to the variation of geochemical characteristics. Arsenic concentrations showed strongly positive correlations with NH4+ and total organic carbon (TOC). Sequencing results revealed that a total of 329–2823 operational taxonomic units (OTUs) were observed at the 97% OTU level. Microbial richness and diversity of high arsenic groundwater samples along the drainage channels were lower than those of low arsenic groundwater samples but higher than those of high arsenic groundwaters from strongly reducing areas. The microbial community structure in groundwater along the drainage channels was different from those in strongly reducing arsenic-rich aquifers of Hetao Plain and other high arsenic groundwater aquifers including Bangladesh, West Bengal, and Vietnam. Acinetobacter and Pseudomonas dominated with high percentages in both high and low arsenic groundwaters. Alishewanella, Psychrobacter, Methylotenera, and Crenothrix showed relatively high abundances in high arsenic groundwater, while Rheinheimera and the unidentified OP3 were predominant populations in low arsenic groundwater. Archaeal populations displayed a low occurrence and mainly dominated by methanogens such as Methanocorpusculum and Methanospirillum. Microbial community compositions were different between high and low arsenic groundwater samples based on the results of principal coordinate

  2. 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.

  3. 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 ...

  4. 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.

  5. 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

  6. 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

  7. NONFARM AGRICULTURAL EMPLOYMENT IN NORTHEAST LOUISIANA--AREA II--WITH IMPLICATIONS FOR DEVELOPING TRAINING PROGRAMS.

    ERIC Educational Resources Information Center

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

    AS PART OF A STATEWIDE STUDY OF NONFARM AGRICULTURAL OCCUPATIONS IN LOUISIANA, 480 FIRMS IN 14 PARISHES WERE SURVEYED TO DETERMINE THE NUMBER OF EMPLOYEES, THE AGRICULTURAL COMPETENCIES NEEDED, AND JOB CHARACTERISTICS. OF THE 6,087 EMPLOYEES, 3,119 NEEDED AGRICULTURAL COMPETENCIES IN 597 DIFFERENT JOB TITLES. NEARLY 60 PERCENT OF THE EMPLOYEES…

  8. 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.

  9. 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.

  10. Pilot project on the resettlement of out-migrant agricultural population in Yangtze Gorges Reservoir Area.

    PubMed

    Zhu, W

    1992-10-01

    A brief summary is provided of the pilot project on the resettlement of the agricultural population in Yangtze Reservoir Area, China. Population needed to be resettled from the area to be flooded by the construction of the Three Gorges Hydropower Station in the middle of the Yangtze River. The submerged area included 19 cities and counties of which 2 are county level cities, 11 county seats, 140 towns and market towns, 326 townships, and 1351 villages. The population to be evacuated totaled 725,500 residents, of whom 392,90 were urban residents and 332,600 were rural residents. The amount of cultivated land lost amounted to 3573 mu (1 mu = 17.5% of an acre). While the hydropower station is being constructed, the population will rise over 20 years to 1 million. The Chinese government has developed a program of resettlement, whereby displaced population receive financial support to develop the economy; the sum appropriated equaled 50 million yuan RMB. So far, the pilot project has been successful. Within the 326 townships affected, only part of the land lying below the highest water level of the reservoir would be affected; the remaining land could be used for resettlement, albeit the land is uncultivated grassland and barren mountains and hills. Resettlement in the area is preferred over long distance migration. The government program will help farmers make full use of the available lands. Suggested crops include mulberry trees, oranges, medical herbs, and other cash crops. Effort will be made to ensure each farmer will receive one mu of economic forest or one mu of cultivated land of high and stable yields. The program aims to guarantee sufficient food supplies and the same standard of living before displacement, as well as the opportunity to create better conditions for alleviating poverty and improvement through increased productivity.

  11. Monitoring the Wheat, Corn and Cotton Areas in AN Eastern Mediterranean Agricultural Basin Between 2007 and 2013

    NASA Astrophysics Data System (ADS)

    Satir, O.; Yeler, O.

    2016-10-01

    Detecting the seasonal agricultural crop pattern accurately is a vital part of the agricultural planning. In this extent, Cukurova Region that is located in Eastern Mediterranean Region of Turkey was evaluated on agricultural landscape pattern. This region is the most productive agricultural region of Turkey also crop variability and yield are higher than many parts of the world. The main agricultural part of the area is called Lower Seyhan Plane (LSP) and it has been formed by the Seyhan, Ceyhan and Berdan rivers. The purpose of the study was to define the wheat, corn and cotton crop pattern using multi-temporal Landsat satellite images and object based classification approach for 2007 and 2013 cropping years. Three main crop's areal difference were evaluated and changes were monitored between 2007 and 2013. The accuracy of the classifications were obtained by the spatial kappa statistics. Overall kappa accuracy was derived to be 0.9. Classification results were shown that wheat areas were decreased 35% and corn and cotton areas were increased 49% and 69% respectively. Particularly, government subventions and market demands were impacted cropping pattern in the region significantly. In addition, multi-temporal Landsat images and object based classification were a great combination to define regional agricultural crop pattern with very good accuracy (>90%).

  12. Analysis of vulnerability factors that control nitrate occurrence in natural springs (Osona Region, NE Spain).

    PubMed

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

    2011-07-15

    Nitrate pollution is one of the main concerns of groundwater management in most of the world's agricultural areas. In the Osona region of NE Spain, high concentrations of nitrates have been reported in wells. This study uses the occurrence of this pollutant in natural springs as an indicator of the sub-surface dynamics of the water cycle and shows how groundwater quality is affected by crop fertilization, as an approach to determine the aquifer vulnerability. Nitrate concentration and other hydrochemical parameters based on a biannual database are reported for approximately 80 springs for the period 2004-2009. The background concentration of nitrate is first determined to distinguish polluted areas from natural nitrate occurrence. A statistical treatment using logistic regression and ANOVA is then performed to identify the significance of the effect of vulnerability factors such as the geological setting of the springs, land use in recharge areas, sampling periods, and chemical parameters like pH and EC, on groundwater nitrate pollution. The results of the analysis identify a threshold value of 7-8 mg NO(3)(-)/L for nitrate pollution in this area. Logistic regression and ANOVA results show that an increase in EC or a decrease in pH values is linked to the possibility of higher nitrate concentrations in springs. These analyses also show that nitrate pollution is more dependent on land use than the geological setting of springs or sampling periods. Indeed, the specific geological and soil features of the uppermost layers in their recharge areas do not contribute to the buffering of nitrate impacts on aquifers as measured in natural springs. Land use, and particularly fertilization practices, are major factors in groundwater vulnerability.

  13. Bayesian nitrate source apportionment to individual groundwater wells in the Central Valley by use of elemental and isotopic tracers

    USGS Publications Warehouse

    Ransom, Katherine M; Grote, Mark N.; Deinhart, Amanda; Eppich, Gary; Kendall, Carol; Sanborn, Matthew E.; Sounders, A. Kate; Wimpenny, Joshua; Yin, Qing-zhu; Young, Megan B.; Harter, Thomas

    2016-01-01

    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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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…

  19. Distribution of Land Use to Purify Contaminated Groundwater by Nitrate

    NASA Astrophysics Data System (ADS)

    Iizumi, Y.; Tanaka, T.; Kinouchi, T.; Tase, N.; Fukami, K.

    2006-12-01

    Groundwater contamination by nitrate results from over-fertilizing and/or inadequate disposal of livestock excreta has been large-scale problem in agricultural area. Because nitrate is primarily transported to streams via ground water flow, explaining actual condition of groundwater is needed to propose an effective measure for the conservation and restoration of sound nitrogen cycle in agricultural river catchments. The purpose of this research was to clarify a triangular relationship between the groundwater quality and flow system, river water quality and land use. The experimental field is located on a slope from Tsukuba tableland to bottomland, which is a part of Nishi- Yata River watershed in Ibaraki Prefecture, Japan. The site area is about 0.0675 square kilometers and the altitude varies from 24 m to 19 m. Land use of tableland, bottomland and intermediate between them are forestland, paddy field and cropland, respectively. Groundwater quality and level were monitored for the year 2004. During the study period significant differences were not observed in groundwater ionic concentrations. Relative high concentrations of dissolved nitrate were detected in cropland (3 - 43 mg/l) and forestland (74 - 179 mg/l). It revealed that there was a purification zone in the paddy field and the area around its 2-4m and denitrification eliminates nitrate-nitrogen. The pressure head converted into hydraulics head, and the groundwater flow were calculated. According to the results, it seems that groundwater flow from tableland to the riverbed through bottomland. It is presumed that groundwater cultivated in cropland with chemical fertilizer pass through the purification zone of nitrate. On the other hand, it is assumed that groundwater containing nitrate originated from inadequate disposal of livestock excreta discharge from forestland does not pass through the depth of this spot. It is suggested that considering flow system of groundwater to manage distribution of land use

  20. 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)

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. Bioremediation of nitrated organics

    SciTech Connect

    Stafford, D.A.; Lappin-Scott, H.; Jass, J.

    1994-12-31

    In the manufacture of nitrated aromatic and heterocyclic compounds intermediates are produced as well as the final products, e.g. TNT (trinitrotoluene), and RDX (cyclotri-methylene trinitramine). The red water produced is a dilute effluent containing TNT and other nitrated intermediates. Many of the intermediates are also to be found in contaminated land areas as well as the primary manufacturing products as contaminants in ground adjacent to production and storage areas. Two intermediates included as by-products are p-nitrophenol and resorcinol; both are hydroxylated aromatics and one (the former) is also nitrated. If these rings can be hydroxylated and oxidized by pure or mixed microbial cultures then the notion of using microbes for the detoxification of a wide range of nitrated aromatics and heterocyclics is possible. It is proposed in the study to accelerate this degradative process in the first instance for p-nitrophenol and resorcinol, and secondly for TNT and RDX. The use of microbes to degrade nitroaromatic compounds such as nitrobenzenes, and mono-nitro phenols, have been described. In order to determine how aromatic degrading bacteria can also degrade substituted and nitrated aromatics several pure and mixed cultures have been utilized to demonstrate enzyme adaptation.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. Wide-area mapping of small-scale features in agricultural landscapes using airborne remote sensing.

    PubMed

    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 m(2). 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.

  13. Exchanges across land-water-scape boundaries in urban systems: strategies for reducing nitrate pollution.

    PubMed

    Cadenasso, M L; Pickett, S T A; Groffman, P M; Band, L E; Brush, G S; Galvin, M F; Grove, J M; Hagar, G; Marshall, V; McGrath, B P; O'Neil-Dunne, J P M; Stack, W P; Troy, A R

    2008-01-01

    Conservation in urban areas typically focuses on biodiversity and large green spaces. However, opportunities exist throughout urban areas to enhance ecological functions. An important function of urban landscapes is retaining nitrogen thereby reducing nitrate pollution to streams and coastal waters. Control of nonpoint nitrate pollution in urban areas was originally based on the documented importance of riparian zones in agricultural and forested ecosystems. The watershed and boundary frameworks have been used to guide stream research and a riparian conservation strategy to reduce nitrate pollution in urban streams. But is stream restoration and riparian-zone conservation enough? Data from the Baltimore Ecosystem Study and other urban stream research indicate that urban riparian zones do not necessarily prevent nitrate from entering, nor remove nitrate from, streams. Based on this insight, policy makers in Baltimore extended the conservation strategy throughout larger watersheds, attempting to restore functions that no longer took place in riparian boundaries. Two urban revitalization projects are presented as examples aimed at reducing nitrate pollution to stormwater, streams, and the Chesapeake Bay. An adaptive cycle of ecological urban design synthesizes the insights from the watershed and boundary frameworks, from new data, and from the conservation concerns of agencies and local communities. This urban example of conservation based on ameliorating nitrate water pollution extends the initial watershed-boundary approach along three dimensions: 1) from riparian to urban land-water-scapes; 2) from discrete engineering solutions to ecological design approaches; and 3) from structural solutions to inclusion of individual, household, and institutional behavior.

  14. 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…

  15. 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

  16. 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.

  17. 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…

  18. 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…

  19. Tick bites on humans in the agricultural and recreational areas in south-eastern Poland.

    PubMed

    Bartosik, Katarzyna; Sitarz, Monika; Szymańska, Jolanta; Buczek, Alicja

    2011-01-01

    The investigations were conducted in the Lublin province (south-eastern Poland) in areas of high agricultural and recreational value. Among the 418 patients admitted to medical clinics due to arthropod bites in the years 2003-2005, 184 people (44%) had been bitten by ticks. As shown by the research, high-risk groups include people whose stay in tick habitats is connected with their occupational work (54.5%) as well as recreation and tourism (45.5%). As many as 78.7% of the patients were attacked by Ixodes ricinus ticks in forests, and much fewer (31.3%) in other habitats located in urban and rural areas. In one case, a Dermacentor reticulatus female was attached to the skin. Ticks were most commonly located on the upper (28.8%) and lower (27.2%) extremities, and on the abdomen (15.8%). Local skin reactions (57.6%) with predominance of erythema were the most prevalent. Combined local and systemic symptoms were reported less frequently (20.1%). The general symptoms were headache (10.8% of patients), fever (5.4%), lymphadenitis (5.9%) and arthralgia (4.3%). No lesions produced by tick bites were reported in 22.3% of the patients. Field studies conducted in 2003-2004 demonstrated that I. ricinus is a common species in the southern part of the Lublin province, where the density of nymphs and adult forms in various localities during the period of peak seasonal activity (in May) ranges from 18.5-26 specimens/1 h of collection. Two tick species, I. ricinus and D. reticulatus, occur in the northern part of the province. The density of I. ricinus nymphs and adult forms as well as D. reticulatus adults is in the range of 2.5-42 specimens/1 hr of collection and 19.5-64.0 speciments/1 hr of collection, respectively. Due to the high risk of tick attacks in the study area, there arises the necessity to permanent the monitoring of ticks numbers and tick-borne diseases.

  20. 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

  1. Microbial oxidation of pyrite coupled to nitrate reduction in anoxic groundwater sediment.

    PubMed

    Jørgensen, Christian Juncher; Jacobsen, Ole Stig; Elberling, Bo; Aamand, Jens

    2009-07-01

    Although many areas in Denmark are intensively agricultured, the discharge of nitrate from groundwater aquifers to surface water is often lower than expected. In this study it is experimentally demonstrated that anoxic nitrate reduction in sandy sediment containing pyrite is a microbially mediated denitrification process with pyrite as the primary electron donor. The process demonstrates a temperature dependency (Q10) of 1.8 and could be completely inhibited by addition of a bactericide (NaN3). Experimentally determined denitrification rates show that more than 50% of the observed nitrate reduction can be ascribed to pyrite oxidation. The apparent zero-order denitrification rate in anoxic pyrite containing sediment at groundwater temperature has been determined to be 2-3 micromol NO3- kg(-1) day(-1). The in situ groundwater chemistry at the boundary between the redoxcline and the anoxic zone reveals that between 65 and 80% of nitrate reduction in the lower part of the redoxcline is due to anoxic oxidation of pyrite by nitrate with resulting release of sulfate. It is concluded that microbes can control groundwater nitrate concentrations by denitrification using primarily pyrite as electron donor at the oxic-anoxic boundary in sandy aquifers thus determining the position and downward progression of the redox boundary between nitrate-containing and nitrate-free groundwater.

  2. 76 FR 46907 - Ammonium Nitrate Security Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-03

    ... used in agricultural operations indicated that ammonium nitrate is the best choice for nitrogen... contains not less than 33 percent nitrogen by weight.'' See 6 U.S.C. 488(1)(A). DHS proposes to use...

  3. 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.

  4. Capture and characterization of particulate phosphorus from farm drainage waters in the Everglades Agricultural Area

    NASA Astrophysics Data System (ADS)

    Bhadha, J. H.; Lang, T.; Daroub, S.

    2012-12-01

    The buildup of highly labile, organic, phosphorus (P)-enriched sediments in farms canals within the Everglades Agricultural Area (EAA) has been associated with the production of floating aquatic vegetation. During drainage events, these sediments are susceptible to transport and contribute to the overall P load. In order to evaluate the total P load exiting the farm canals, a settling tank experiment was conducted to capture the sediments during drainage events from eight farms. Drainage water was channelized through two 200L polypropylene collection tanks which allowed sediments to settle at the bottom based on its particle size. Water was carefully siphoned out of the tanks and the sediments collected for analyses. A five step P-fractionation process was used to distinguish organic (o) and inorganic (i) forms of P: KCl extractable P, NaOH extractable P, HCl extractable P, and residual P. The KCl-Pi fraction represents the labile Pi that is water soluble and exchangeable (loosely adsorbed); NaOH extractable P represents Fe- and Al- bound inorganic P (NaOH-Pi) and organic P associated with humic and fulvic acids (NaOH-Po). The HCl-Pi fraction includes Ca- and Mg- bound P, while Residue-P represents recalcitrant organic P compounds and P bound to minerals. The sediments were also used to conduct a P-flux study under both aerobic and anaerobic conditions. Our goal is to provide growers with vital information and insight into P loading that will help them in their efforts to reduce off-farm P loads in the EAA.

  5. Insensitive Ammonium Nitrate.

    DTIC Science & Technology

    is reduced by replacing the ammonium nitrate with a solid solution of potassium nitrate in form III ammonium nitrate wherein the potassium nitrate...constitutes from more than zero to less than 50 weight percent of the solid solution . (Author)

  6. Emissions from Combustion of Open Area Sources: Prescribed Forest and Agricultural Burns

    EPA Science Inventory

    Emissions from wildfires and prescribed forest and agricultural burns generate a variety of emissions that can cause adverse health effects for humans, contribute to climate change, and decrease visibility. Only limited pollutant data are available for these sources, particularly...

  7. Dynamic factor analysis of groundwater quality trends in an agricultural area adjacent to Everglades National Park

    NASA Astrophysics Data System (ADS)

    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-NO 3-, N-NH 4+, P-PO 43-, 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-NO 3-, P-PO 43-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-NH 4+, 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

  8. Development and testing of method for assessing and mapping agricultural areas susceptible to atrazine leaching in the state of Washington

    USGS Publications Warehouse

    Voss, Frank D.

    2003-01-01

    In a joint effort by the Washington State Department of Agriculture, the Washington Department of Ecology, and the U.S. Geological Survey, the Environmental Protection Agency's Pesticide Root Zone Model and a Geographic Information System were used to develop and test a method for screening and mapping the susceptibility of ground water in agricultural areas to pesticide contamination. The objective was to produce a map that would be used by the Washington State Department of Agriculture to allocate resources for monitoring pesticide levels in ground water. The method was tested by producing a map showing susceptibility to leaching of the pesticide atrazine for the Columbia Basin Irrigation Project, which encompasses an area of intensive agriculture in eastern Washington. The reliability of the atrazine map was assessed by using statistical procedures to determine whether the median of the percentage of atrazine simulated to leach below the root zone in wells where atrazine was detected was statistically greater than the median percentage at wells where atrazine was not detected (at or above 0.001 microgram per liter) in 134 wells sampled by the U.S. Geological Survey. A statistical difference in medians was not found when all 134 wells were compared. However, a statistical difference was found in medians for two subsets of the 134 wells that were used in land-use studies (studies examining the quality of ground water beneath specific crops). The statistical results from wells from the land-use studies indicate that the model potentially can be used to map the relative susceptibility of agricultural areas to atrazine leaching. However, the distinction between areas of high and low susceptibility may not yet be sufficient to use the method for allocating resources to monitor water quality. Several options are offered for improving the reliability of future simulations.

  9. Satellite-based estimation of watershed groundwater storage dynamics in a freeze-thaw area under intensive agricultural development

    NASA Astrophysics Data System (ADS)

    Ouyang, Wei; Liu, Bing; Wu, Yuyang

    2016-06-01

    Understanding the temporal-spatial characteristics of groundwater storage is critical for agricultural planning and management in the future, thereby causing more challenges in water resource management. However, the special hydrological features of the snow water equivalent, soil moisture, and total canopy water storage in the freeze-thawing agricultural area requires the innovative methods for the water resource analysis. The watershed land cover variation and the expanding pattern of the farmlands over a decade were identified using the TM-Landsat series data. Combined with the traditional measurements of the water resource, the monthly gravity field data from the Gravity Recovery And Climate Experiment (GRACE) was validated and applied. The water resources distribution based on the remotely sensed data demonstrated that the forest in the watershed center had a larger amount of water storage. The inter-annual and seasonal variability of total water storage (TWS) over the agricultural area was analyzed and the higher value appeared in the thawing period of April. The correlations of the TWS streamflow, soil moisture and snow water equivalent with precipitation were all identified. The precipitation was the dominant factor for the watershed TWS and the groundwater dynamics. Under the similar precipitation condition, the lower groundwater storage in recent years was the consequence of the expanding of farmland. The watershed averaged decrease rate of groundwater level from 2003 to 2012 was 1.06 mm/year, which was much lower than the rates in other agricultural areas. The freeze-thawing process with smelt snow and rainfall in summer had more time and chance to recharge the groundwater resource and provided the sustainable water resource. This study proved that the application of GRACE was an effective method for the temporal-spatial estimation of the TWS anomalies in the freeze-thawing agricultural area.

  10. [Changes of China agricultural climate resources under the background of climate change. III. Spatiotemporal change characteristics of agricultural climate resources in Northwest Arid Area].

    PubMed

    Xu, Chao; Yang, Xiao-guang; Li, Yong; Wang, Wen-feng

    2011-03-01

    By using the 1961-2007 daily weather data from 78 meteorological stations in Northwest Arid Area, this paper analyzed the spatiotemporal characteristics of agricultural climate resources, i.e., heat, light, and precipitation, in the area, both in the whole year and in temperature-defined growth seasons of chimonophilous and thermophilic crops. In 1961-2007, the mean annual temperature in the area had an increasing trend, and the climate tendency rate was 0.35 degrees C x (10 a)(-1). The accumulated temperature in temperature-defined growth seasons of both chimonophilous and thermophilic crops also had an increasing trend, and the climate tendency rate was 67 and 50 degrees C d x (10 a)(-1), respectively. The annual sunshine hours in most stations of the research area had an obvious decreasing trend, but the sunshine hours during the temperature-defined growth seasons of chimonophilous and thermophilic crops had an increasing trend, except that in most regions of Xin-jiang and east Ningxia Plain. The annual reference evapotranspiration in most regions of the study area tended to decrease, while the reference evapotranspiration during temperature-defined growth seasons of chimonophilous and thermophilic crops tended to decrease in the west but increase in the east. Compared with that in 1961-1980, the precipitation both in the whole year and in temperature-defined growth seasons of chimonophilous and thermophilic crops in 1981-2007 increased, and the increment reduced progressively from the northwest to the southeast.

  11. PiSAR-L2 observation of agricultural area damaged by seawater during the Great East Japan Earthquake in 2011

    NASA Astrophysics Data System (ADS)

    Watanabe, Manabu; Kawano, Noriyuki; Naoki, Kazuhiro; Shimada, Masanobu

    2012-11-01

    On March 11, 2011, a massive earthquake occurred on the eastern coast of Japan. The magnitude 9.0 quake was the most powerful ever recorded in Japan. The height of the tsunami that followed the earthquake was estimated to be more than 10 m. The water reached a few kilometers inland and resulted in thousands of casualties as well as serious damage to buildings and agricultural areas along the coastline. Several PiSAR-L2 observations were carried out in these tsunamiaffected areas from April to September in 2012, and field experiments were performed in agricultural areas that had been damaged by seawater. The complex dielectric constant and the electrical conductivity of the soil were measured to estimate the soil's salinity. The imaginary part of the dielectric constant for a tsunami-damaged area 0.7 km from the coastline was shown to be 37.1 at 1 GHz, and the electric conductivity was shown to be 7.8 mS/cm. These values exceeded those from non-damaged inland areas. One of the full polarimetric parameters, co-polarization backscattering ratio (σ0HH/σ0VV) derived from PiSAR-L2 data, were examined and compared for damaged/non-damaged areas. The analysis indicates that the higher-salinity area was well detected by σ0HH/σ0VV. However, water areas and flat surfaces covered by gravel exhibit similar characteristics, and this may result in the false detection of salt-affected agricultural areas.

  12. Eco-environment contribution of agroforestry to agriculture development in the plain area of China--Huai' an Prefecture, Jiangsu Province as the case study area.

    PubMed

    Ren, Hong-chang; Lu, Yong-long; Liu, Can; Meng, Qing-hua; Shi, Ya-juan

    2005-01-01

    For improving the environmental quality and ensuring supply of wood and non-timber forest products, many forests have been planted in plain areas of China. Scientists have studied their benefits, almost all of the approaches were based on fixed-point data, and few was considered on the non-efficient factors and temporal scale effects. This paper studies the positive and negative benefits at a large temporal scale, and the effects of plain afforestation on stockbreeding and rural economy. The benefits of plain afforestation, correlation coefficiency of agroforestry and production factors are analyzed via stochastic frontier modeling in Huanghuaihai Plain Area of China; elastic coefficient of agroforestry, husbandry, farming, and total output of agricultural sector are calculated through adopting partial differential equation. Some conclusions can be drawn that, plain forests have an important effect on the development of plain agriculture. But shelterbelts and small-scale forests have different effect on the development of agricultural economy. Shelterbelts have negative effect on the industries, but small-scale forest has positive effect. On the whole, contribution of forest resource to value of animal husbandry and gross production value of agriculture is positive, and to the value of farming is negative.

  13. A Delphi Approach to the Preparation of Early-Career Agricultural Educators in the Curriculum Area of Agricultural Mechanics: Fully Qualified and Highly Motivated or Status Quo?

    ERIC Educational Resources Information Center

    Saucier, P. Ryan; McKim, Billy R.; Tummons, John D.

    2012-01-01

    According to the National Research Agenda for Agricultural Education and Communication, preservice agriculture teacher education programs should "prepare and provide an abundance of fully qualified and highly motivated agricultural educators at all levels" (Osborne, 2007, 8). The lack of preparation of entry career agricultural educators…

  14. Severe situation of rural nonpoint source pollution and efficient utilization of agricultural wastes in the Three Gorges Reservoir Area.

    PubMed

    Zhang, Tong; Ni, Jiupai; Xie, Deti

    2015-11-01

    Rural nonpoint source (NPS) pollution caused by agricultural wastes has become increasingly serious in the Three Gorges Reservoir Area (TGRA), significantly affecting the reservoir water quality. The grim situation of rural NPS pollution in the TGRA indicated that agrochemicals (chemical fertilizer and pesticide) were currently the highest contributor of rural NPS pollution (50.38%). The harmless disposal rates of livestock excrement, crop straws, rural domestic refuse, and sewage also cause severe water pollution. More importantly, the backward agricultural economy and the poor environmental awareness of farmers in the hinterland of the TGRA contribute to high levels of rural NPS pollution. Over the past decade, researchers and the local people have carried out various successful studies and practices to realize the effective control of rural NPS pollution by efficiently utilizing agricultural wastes in the TGRA, including agricultural waste biogas-oriented utilization, crop straw gasification, decentralized land treatment of livestock excrement technology, and crop straw modification. These technologies have greatly increased the renewable resource utilization of agricultural wastes and improved water quality and ecological environment in the TGRA.

  15. Analysis of bioavailable Ge in agricultural and mining-affected-soils in Freiberg area (Saxony, Germany)

    NASA Astrophysics Data System (ADS)

    Wiche, Oliver; Székely, Balázs; Kummer, Nicolai-Alexeji; Heinemann, Ute; Heilmeier, Hermann

    2014-05-01

    Germanium (Ge) concentrations in different soil fraction were investigated using a sequential selective dissolution analysis and a rhizosphere-based single-step extraction method for the identification of Ge-bearing soil fractions and prediction of bioavailability of Ge in soil to plants. About 50 soil samples were collected from various soil depths (horizons A and B) and study sites with different types of land use (dry and moist grassland, arable land, mine dumps) in Freiberg area (Saxony, Germany). Ge has been extracted in six soil fractions: mobile fraction, organic matter and sulfides, Mn- and Fe-oxides (amorphous and crystalline), and kaolinite and phytoliths, and residual fraction. The rhizosphere-based method included a 7-day-long extraction sequence with various organic acids like citric acid, malic acid and acetic acid. For the residue the aforementioned sequential extraction has been applied. The Ge-content of the samples have been measured with ICP-MS using rhodium internal standard and two different soil standards. Total Ge concentrations were found to be in the range of 1.6 to 5.5 ppm with highest concentrations on the tailing site in the mining area of Altenberg. The mean Ge concentration in agriculturally used soils was 2.6 ± 0.67 ppm, whereas the maximum values reach 2.9 ± 0.64 ppm and 3.2 ± 0.67 ppm in Himmelsfürst and in a grassland by the Mulde river, respectively. With respect to the fractions, the vast majority of Ge is contained in the last three fractions, indicating that the bioavailable Ge is typically low in the samples. On the other hand at the soil horizons A at the aforementioned two sites characterised by high total Ge, together with that of Reiche Zeche mine dump have also the highest concentrations of Ge in the first three fractions, reaching levels of 1.74 and 0.98 ppm which account for approximately 40% of the total Ge content. Ge concentrations of soil samples extracted with 0.01 or 0.1 M citric acid and malic acid were

  16. Soil respiration and carbon loss relationship with temperature and land use conversion in freeze-thaw agricultural area.

    PubMed

    Ouyang, Wei; Lai, Xuehui; Li, Xia; Liu, Heying; Lin, Chunye; Hao, Fanghua

    2015-11-15

    Soil respiration (Rs) was hypothesized to have a special response pattern to soil temperature and land use conversion in the freeze-thaw area. The Rs differences of eight types of land use conversions during agricultural development were observed and the impacts of Rs on soil organic carbon (SOC) loss were assessed. The land use conversions during last three decades were categorized into eight types, and the 141 SOC sampling sites were grouped by conversion type. The typical soil sampling sites were subsequently selected for monitoring of soil temperature and Rs of each land use conversion types. The Rs correlations with temperature at difference depths and different conversion types were identified with statistical analysis. The empirical mean error model and the biophysical theoretical model with Arrhenius equation about the Rs sensitivity to temperature were both analyzed and shared the similar patterns. The temperature dependence of soil respiration (Q10) analysis further demonstrated that the averaged value of eight types of land use in this freeze-thaw agricultural area ranged from 1.15 to 1.73, which was lower than the other cold areas. The temperature dependence analysis demonstrated that the Rs in the top layer of natural land covers was more sensitive to temperature and experienced a large vertical difference. The natural land covers exhibited smaller Rs and the farmlands had the bigger value due to tillage practices. The positive relationships between SOC loss and Rs were identified, which demonstrated that Rs was the key chain for SOC loss during land use conversion. The spatial-vertical distributions of SOC concentration with the 1.5-km grid sampling showed that the more SOC loss in the farmland, which was coincided with the higher Rs in farmlands. The analysis of Rs dynamics provided an innovative explanation for SOC loss in the freeze-thaw agricultural area. The analysis of Rs dynamics provided an innovative explanation for SOC loss in the freeze

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

    PubMed Central

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

    2016-01-01

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

  18. Environmental land use conflicts in catchments: A major cause of amplified nitrate in river water.

    PubMed

    Pacheco, F A L; Sanches Fernandes, L F

    2016-04-01

    Environmental land use conflicts are uses of the land that ignore soil capability. In this study, environmental land use conflicts were investigated in mainland Portugal, using Partial Least Squares (PLS) regression combined with GIS modeling and a group of 85 agricultural watersheds (with >50% occupation by agriculture) as work sample. The results indicate a dominance of conflicts in a region where vineyards systematically invaded steep hillsides (the River Douro basin), where forests would be the most appropriate use. As a consequence of the conflicts, nitrate concentrations in rivers and lakes from these areas have increased, sometimes beyond the legal limit of 50mg/L imposed by the European and Portuguese laws. Excessive nitrate concentrations were also observed along the Atlantic coast of continental Portugal, but associated to a combination of other factors: large population densities, and incomplete coverage by sewage systems and inadequate functioning of wastewater treatment plants. Before this study, environmental land use conflicts were never recognized as possible boost of nitrate concentrations in surface water. Bearing in mind the consequences of drinking water nitrate for human health, a number of land use change scenarios were investigated to forecast their impact on freshwater nitrate concentrations. It was seen that an aggravation of the conflicts would duplicate the number of watersheds with maximum nitrate concentrations above 50mg/L (from 11 to 20 watersheds), while the elimination of the conflicts would greatly reduce that number (to 3 watersheds).

  19. Trend Analyses of Nitrate in Danish Groundwater

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    This presentation assesses the long-term development in the oxic groundwater nitrate concentration and nitrogen (N) loss due to intensive farming in Denmark. Firstly, 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. Secondly, knowledge about the N surplus in Danish agriculture since 1950 is used as an indicator of the potential loss of N. Thirdly, groundwater recharge CFC (Chlorofluorocarbon) age determination allows linking of the first two dataset. 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. Are the Danish groundwater monitoring strategy obtimal for detection of nitrate trends? Will the nitrate concentrations in Danish groundwater continue to decrease or are the Danish nitrate concentration levels now appropriate according to the Water Framework Directive?

  20. Evaluation of area source models to predict near ground level concentrations due to emissions released during agricultural applications.

    PubMed

    Nimmatoori, Praneeth; Kumar, Ashok

    2013-02-15

    The modeling of emissions to predict concentrations at downwind distances close to the area sources such as agricultural is of great interest for practical applications. In this study, three area source models used for agricultural sources - the Shear, the Parker, and the Smith models - are compared using two field data sets. Statistical performance measures are used to evaluate and compare the performance of the models. The evaluation results showed that the Shear model performed better than the Parker and the Smith models for all the near downwind distances under unstable conditions (B and C). The analysis of model algorithms indicate that the relatively better performance of the Shear model is due to the incorporation of a variation of wind speed and vertical eddy diffusivity (atmospheric turbulence) with height above the ground.

  1. Evaluating Chemical Tracers as Indicators of Nitrate-Nitrogen Sources in Groundwater

    NASA Astrophysics Data System (ADS)

    Nitka, A.; DeVita, W.; McGinley, P.

    2014-12-01

    Groundwater nitrate-N concentrations greater than 3 mg/L usually indicate contamination from either agriculture or wastewater disposal. The objective of this study was to use chemical indicators to reliably determine sources of nitrate contamination in private wells. We developed an analytical method for a suite of human waste indicators. The selection of chemical tracers was based on their likely occurrence and mobility in groundwater. The suite included artificial sweeteners, pharmaceuticals and personal care products. Pesticide metabolites were used to identify contamination due to agricultural practices. A densely populated suburban area with adjacent agricultural land was selected. Eighteen private water supply wells and six monitoring wells were analyzed for nitrate-N and contaminant indicators. All of the wells with nitrate concentrations greater than 3 mg/L had at least one chemical indicator. Of these, 90% had two or more human waste contaminants, 40% had pesticide metabolites, and 30% had both. Of the wells with nitrate greater than 10 mg/L, 80% had two or more human waste indicators, 70% had pesticide metabolites, and 50% had both. The results of this research will help direct land management decisions and selection of appropriate water treatment options.

  2. Identification of groundwater nitrate sources in pre-alpine catchments: a multi-tracer approach

    NASA Astrophysics Data System (ADS)

    Stoewer, Myriam; Stumpp, Christine

    2014-05-01

    Porous aquifers in pre-alpine areas are often used as drinking water resources due to their good water quality status and water yield. Maintaining these resources requires knowledge about possible sources of pollutants and a sustainable management practice in groundwater catchment areas. Of particular interest in agricultural areas, like in pre-alpine regions, is limiting nitrate input as main groundwater pollutant. Therefore, the objective of the presented study is i) to identify main nitrate sources in a pre-alpine groundwater catchment with current low nitrate concentration using stable isotopes of nitrate (d18O and d15N) and ii) to investigate seasonal dynamics of nitrogen compounds. The groundwater catchment areas of four porous aquifers are located in Southern Germany. Most of the land use is organic grassland farming as well as forestry and residential area. Thus, potential sources of nitrate mainly are mineral fertilizer, manure/slurry, leaking sewage system and atmospheric deposition of nitrogen compounds. Monthly freshwater samples (precipitation, river water and groundwater) are analysed for stable isotope of water (d2H, d18O), the concentration of major anions and cations, electrical conductivity, water temperature, pH and oxygen. In addition, isotopic analysis of d18O-NO3- and d15N-NO3- for selected samples is carried out using the denitrifier method. In general, all groundwater samples were oxic (10.0±2.6mg/L) and nitrate concentrations were low (0.2 - 14.6mg/L). The observed nitrate isotope values in the observation area compared to values from local precipitation, sewage, manure and mineral fertilizer as well as to data from literature shows that the nitrate in freshwater samples is of microbial origin. Nitrate derived from ammonium in fertilizers and precipitation as well as from soil nitrogen. It is suggested that a major potential threat to the groundwater quality is ammonia and ammonium at a constant level mainly from agriculture activities as

  3. Perceived damage and areas of needed research for wildlife pests of California agriculture.

    PubMed

    Baldwin, Roger A; Salmon, Terrell P; Schmidt, Robert H; Timm, Robert M

    2014-06-01

    Many wildlife species cause extensive damage to a variety of agricultural commodities in California, with estimates of damage in the hundreds of millions annually. Given the limited availability of resources to solve all human-wildlife conflicts, we should focus management efforts on issues that provide the greatest benefit to agricultural commodities in California. This survey provides quantitative data on research needs to better guide future efforts in developing more effective, practical and appropriate methods for managing these species. We found that ground squirrels, pocket gophers, birds, wild pigs, coyotes and voles were the most common agricultural wildlife pest species in California. The damage caused by these species could be quite high, but varied by agricultural commodity. For most species, common forms of damage included loss of crop production and direct death of the plant, although livestock depredation was the greatest concern for coyotes. Control methods used most frequently and those deemed most effective varied by pest species, although greater advancements in control methods were listed as a top research priority for all species. Collectively, the use of toxicants, biocontrol and trapping were the most preferred methods for control, but this varied by species. In general, integrated pest management practices were used to control wildlife pests, with a special preference for those approaches that were efficacious and quick and inexpensive to apply. This information and survey design should be useful in establishing research and management priorities for wildlife pest species in California and other similar regions.

  4. A Review of Effectiveness of Vegetative Buffers on Sediment Trapping in Agricultural Areas

    EPA Science Inventory

    In recent years, there has been growing recognition of the importance of riparian buffers between agricultural fields and waterbodies. Riparian buffers play an important role in mitigating the impacts of land use activities on water quality and aquatic ecosystems. However, eval...

  5. Does area deprivation modify the association between exposure to a nitrate and low-dose atrazine metabolite mixture in drinking water and small for gestational age? A historic cohort study.

    PubMed

    Limousi, F; Albouy-Llaty, M; Carles, C; Dupuis, A; Rabouan, S; Migeot, V

    2014-04-01

    Birth weight may be influenced by environmental and socio-economic factors that could interact. The main objective of our research was to investigate whether area deprivation may modify the association between drinking water exposure to a mixture of atrazine metabolites and nitrates during the second trimester of pregnancy and prevalence of small for gestational age (SGA) neonates. We conducted a historic cohort study in Deux-Sèvres, France between 2005 and 2010, using birth records, population census and regularly performed drinking water withdrawals at community water systems. Exposure to an atrazine metabolite/nitrate mixture in drinking water was divided into six classes according to the presence or absence of atrazine metabolites and to the terciles of nitrate concentrations in each trimester of pregnancy. We used a logistic regression to model the association between SGA and mixture exposure at the second trimester while taking into account the area deprivation measured by the Townsend index as an effect modifier and controlling for the usual confounders. We included 10,784 woman-neonate couples. The risk of SGA when exposed to second tercile of nitrate without atrazine metabolites was significantly greater in women living in less deprived areas (OR = 2.99; 95 % CI (1.14, 7.89)), whereas it was not significant in moderately and more deprived areas. One of the arguments used to explain this result is the presence of competing risk factors in poorer districts.

  6. Dryland Soil Hydrological Processes and Their Impacts on the Nitrogen Balance in a Soil-Maize System of a Freeze-Thawing Agricultural Area

    PubMed Central

    Ouyang, Wei; Chen, Siyang; Cai, Guanqing; Hao, Fanghua

    2014-01-01

    Understanding the fates of soil hydrological processes and nitrogen (N) is essential for optimizing the water and N in a dryland crop system with the goal of obtaining a maximum yield. Few investigations have addressed the dynamics of dryland N and its association with the soil hydrological process in a freeze-thawing agricultural area. With the daily monitoring of soil water content and acquisition rates at 15, 30, 60 and 90 cm depths, the soil hydrological process with the influence of rainfall was identified. The temporal-vertical soil water storage analysis indicated the local albic soil texture provided a stable soil water condition for maize growth with the rainfall as the only water source. Soil storage water averages at 0–20, 20–40 and 40–60 cm were observed to be 490.2, 593.8, and 358 m3 ha−1, respectively, during the growing season. The evapo-transpiration (ET), rainfall, and water loss analysis demonstrated that these factors increased in same temporal pattern and provided necessary water conditions for maize growth in a short period. The dry weight and N concentration of maize organs (root, leaf, stem, tassel, and grain) demonstrated the N accumulation increased to a peak in the maturity period and that grain had the most N. The maximum N accumulative rate reached about 500 mg m−2d−1 in leaves and grain. Over the entire growing season, the soil nitrate N decreased by amounts ranging from 48.9 kg N ha−1 to 65.3 kg N ha−1 over the 90 cm profile and the loss of ammonia-N ranged from 9.79 to 12.69 kg N ha−1. With soil water loss and N balance calculation, the N usage efficiency (NUE) over the 0–90 cm soil profile was 43%. The soil hydrological process due to special soil texture and the temporal features of rainfall determined the maize growth in the freeze-thawing agricultural area. PMID:25000400

  7. Impacts of Watershed Characteristics and Crop Rotations on Winter Cover Crop Nitrate-Nitrogen Uptake Capacity within Agricultural Watersheds in the Chesapeake Bay Region

    PubMed Central

    Lee, Sangchul; Yeo, In-Young; Sadeghi, Ali M.; McCarty, Gregory W.; Hively, W. Dean; Lang, Megan W.

    2016-01-01

    The adoption rate of winter cover crops (WCCs) as an effective conservation management practice to help reduce agricultural nutrient loads in the Chesapeake Bay (CB) is increasing. However, the WCC potential for water quality improvement has not been fully realized at the watershed scale. This study was conducted to evaluate the long-term impact of WCCs on hydrology and NO3-N loads in two adjacent watersheds and to identify key management factors that affect the effectiveness of WCCs using the Soil and Water Assessment Tool (SWAT) and statistical methods. Simulation results indicated that WCCs are effective for reducing NO3-N loads and their performance varied based on planting date, species, soil characteristics, and crop rotations. Early-planted WCCs outperformed late-planted WCCs on the reduction of NO3-N loads and early-planted rye (RE) reduced NO3-N loads by ~49.3% compared to the baseline (no WCC). The WCCs were more effective in a watershed dominated by well-drained soils with increased reductions in NO3-N fluxes of ~2.5 kg N·ha-1 delivered to streams and ~10.1 kg N·ha-1 leached into groundwater compared to poorly-drained soils. Well-drained agricultural lands had higher transport of NO3-N in the soil profile and groundwater due to increased N leaching. Poorly-drained agricultural lands had lower NO3-N due to extensive drainage ditches and anaerobic soil conditions promoting denitrification. The performance of WCCs varied by crop rotations (i.e., continuous corn and corn-soybean), with increased N uptake following soybean crops due to the increased soil mineral N availability by mineralization of soybean residue compared to corn residue. The WCCs can reduce N leaching where baseline NO3-N loads are high in well-drained soils and/or when residual and mineralized N availability is high due to the cropping practices. The findings suggested that WCC implementation plans should be established in watersheds according to local edaphic and agronomic

  8. Reactive Transport of Nitrate in Northern California Groundwater basins: An Integrated Characterization and Modeling Approach

    NASA Astrophysics Data System (ADS)

    Esser, B. K.; Moran, J. E.; Hudson, G. B.; Carle, S. F.; McNab, W.; Tompson, A. F.; Moore, K.; Beller, H.; Kane, S.; Eaton, G.

    2003-12-01

    More than 1/3 of active public drinking water supply wells in California produce water with nitrate-N levels indicative of anthropogenic inputs (> 4 mg/L). Understanding how the distribution of nitrate in California groundwater basins will evolve is vital to water supply and infrastructure planning. To address this need, we are studying the basin-scale reactive transport of nitrate in the Livermore and Llagas basins of Northern California. Both basins have increasingly urban populations heavily reliant on groundwater. A distinct nitrate "plume" exists in the Livermore Basin (Alameda County) whereas pervasive nitrate contamination exists in shallow groundwaters of the Llagas Basin (Santa Clara County). The sources and timing of nitrate contamination in these basins are not definitively known; septic systems, irrigated agriculture and livestock operations exist or have existed in both areas. The role of denitrification in controlling nitrate distribution is also unknown; dissolved oxygen levels are sufficiently low in portions of each basin as to indicate the potential for denitrification. We have collected water from 60 wells, and are determining both groundwater age (by the 3H/3He method) and the extent of denitrification (by the excess N2 method). Excess nitrogen is being determined by both membrane-inlet and noble gas mass spectrometry, using Ar and Ne content to account for atmospheric N2. We are also analyzing for stable istotopes of nitrate and water, nitrate co-contaminants, and general water quality parameters. Preliminary analysis of archival water district data from both basins suggests positive correlations of nitrate with Ca+2, Mg+2 and bicarbonate and negative correlation with pH. In the Llagas Basin, a negative correlation also exists between nitrate and temperature. Flow path-oriented reactive transport modeling is being explored as a tool to aid in the identification of both the sources of nitrate and evidence for denitrification in both basins

  9. Detection of Manure-Derived Organic Compounds in Rivers Draining Agricultural Areas of Intensive Manure Spreading

    NASA Astrophysics Data System (ADS)

    Jardé, E.; Gruau, G.

    2006-12-01

    This study presents the potentiality of organic markers to trace the impact of animal manure in soils and rivers draining agricultural watersheds. As described by Gruau et al. (in this session), the analysis of long term records of dissolved organic matter (DOM) in five watersheds in Brittany (western of France) shows divergent trends which can not be explained solely by global changes. One alternative explanation could be that long- term records of DOM in rivers are controlled by human activities, and notably by agricultural practices. In Brittany, the agricultural intensification led to an over-application of animal manures to soils. This practice can strongly increase the amount of soil-water extractable organic matter, thereby leading to an increase of organic matter fluxes in agricultural landscapes and then to a contamination of river waters. Such an hypothesis deserves consideration in view of the massive manure fluxes that are disposed on agricultural land in many parts of the world. In this goal, our study aimed at determining potential sources of organic matter and molecular markers or specific distributions in rivers draining agricultural watersheds. In this study we focused on the analysis of pig slurries because of the importance of pig production in Brittany. The analysis of pig slurry evidenced the presence of coprostanol (5β) as a specific marker, originating from the bio- hydrogenation of cholesterol by anaerobic bacteria. The difference with other animal or human wastes has been evidenced by two ratios: 5β/C27 and C29/C27. After the validation of the ability of coprostanol to be a molecular marker of pig slurry, our analysis has been focused on the OM of watersheds in Brittany showing divergent evolutions. The results show a systematic relation between the C29/C27 and 5β/C27 ratios and the type of animal breeding in each watershed. This study allows us to evidence the impact of animal breeding activities in the analysed rivers. Such a study

  10. Nitrate in public water supplies and the risk of renal cell carcinoma.

    PubMed

    Ward, Mary H; Rusiecki, Jennifer A; Lynch, Charles F; Cantor, Kenneth P

    2007-12-01

    Drinking water and dietary sources of nitrate and nitrite can react in vivo with amines and amides to form N-nitroso compounds (NOC), potent animal carcinogens. Nitrate is a widespread contaminant of drinking water supplies especially in agricultural areas. We conducted a population-based case-control study of renal cell carcinoma in 1986-1989 in Iowa, a state with elevated levels in many public water supplies. We collected a lifetime water source history, but due to limited monitoring data, most analyses focused on the subpopulation, who used Iowa public supplies with nitrate measurements (actual or imputed data) for > or = 70% of their person-years since 1960 (201 cases, 1,244 controls). We computed the average nitrate level and years using a public supply with nitrate levels >5 and >10 mg/l. Dietary nitrate and nitrite were estimated from a 55-item food frequency questionnaire. There was no association of renal cell carcinoma with the average nitrate level and years using public supplies >5 and >10 mg/l nitrate-nitrogen (10+ years >5 mg/l odds ratio (OR) = 1.03, 95% confidence interval (CI) 0.66, 1.60). However, higher nitrate exposure was associated with an increased risk among subgroups with above the median red meat intake (10+ years >5 mg/l OR = 1.91, 95% CI 1.04-3.51) or below the median vitamin C intake (10+ years >5 mg/l OR = 1.90, 95% CI 1.01, 3.56), dietary factors that increase the endogenous formation of NOC. Exclusion of long-term Des Moines residents, a large proportion of the high exposure categories, attenuated the association. These findings deserve additional study in populations with high water nitrate intake and information on dietary intakes.

  11. [Characteristics of Phthalic Acid Esters in Agricultural Soils and Products in Areas of Zhongshan City, South China].

    PubMed

    Li, Bin; Wu, Shan; Liang, Jin-ming; Liang, Wen-li; Chen, Gui-xian; Li, Yong-jun; Yang, Guo-yi

    2015-06-01

    In order to investigate and assess the pollution level of phthalic acid esters (PAEs) in farm soils and products from typical agricultural fields in areas of Zhongshan City, Guangdong Province, South China, 65 topsoil and 37 agricultural product samples were collected and contents of 6 PAEs compounds that classified by the U. S. Environmental Protection Agency (EPA) as priority pollutants were determined by the GC-FID. The results indicated that total contents of the PAEs (∑ PAEs) in soils ranged from 0. 14 to 1. 14 mg x kg(-1), and the mean value was 0.43 mg x kg(-1), with the detected ratio of 100%. Various concentrations of PAEs differed in three land-use types were ordered by vegetable soil > orchard soil > paddy soil. Comparing with six U.S. EPA priority pollutants of PAEs, the contents of Di-n-butyl phthalate (DBP) and Dimethyl phthalate ( DMP) in soils exceeded the control limits of PAEs in the American soil by 93.85% and 27.69% respectively, but the rest four PAEs compounds were lower than the control limits. Generally, the pollution level of soils contaminated by PAEs in agricultural fields of Zhongshan City was relatively low. The contents of 3 PAEs in agricultural products ranged from 0.15 to 3.15 mg x kg(-1) with the average of 1.12 mg x kg(-1), which was lower than the suggested standards in USA and Europe and with low health risk. Meanwhile, ∑ PAEs concentrations in vegetables were higher than those both in rice and fruits. DBP and DEHP were the main components of PAEs both in agricultural soils and products, with higher percentage contents and detected ratio. ∑ PAEs and DBP contents in various agricultural products-soils had a significantly positive correlation, with Pearson coefficients (r) in vegetables-vegetable soils were 0.81 (P = 0.000), 0.75 (P = 0.000), and corresponding r among rice-paddy soil and fruits-fruit soils were 0.74 (P = 0.036), 0.65 (P = 0.041) and 0.66 (P = 0.029), 0.78 (P = 0.045), respectively. Although there existed a

  12. Impact of nitrates in drinking water on cancer mortality in Valencia, Spain.

    PubMed

    Morales-Suárez-Varela, M M; Llopis-Gonzalez, A; Tejerizo-Perez, M L

    1995-02-01

    The concentrations of nitrates in public drinking water in the Mediterranean coastal province of Valencia are not only the highest in Spain but also in the whole of Europe. Intensive agricultural practices involve a traditional and growing use of nitrogen fertilizers. This and the terrain--poorly consolidated and porous in areas--favors the accumulation of nitrates in underground aquifers, thereby perhaps accounting for this contamination. The possible conversion of nitrates to nitrites under certain conditions of gastric achlorhydria, followed by their transformation to nitrosamines--substances known to be carcinogenic in experimental models--has led to a number of epidemiological studies of the possible relationship between high nitrate levels in public drinking water and mortality due to different cancers. The aim of the present study was to analyze the relationship between different levels of exposure to nitrates in the drinking water of the 258 municipalities in the province of Valencia and mortality due to cancer of the stomach, bladder, prostate and colon in this population. The cancer mortality rate was found to rise with increasing exposure to nitrates in the case of gastric cancer in both sexes, and in prostate cancer. These same results were obtained on calculating relative risk for the different age groups associated with the consumption of drinking water containing different levels of nitrates.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Nitrate pollution and its transfer in surface water and groundwater in irrigated areas: a case study of the Piedmont of South Taihang Mountains, China.

    PubMed

    Li, Jing; Li, Fadong; Liu, Qiang; Suzuki, Yoshimi

    2014-12-01

    Irrigation projects have diverted water from the lower reaches of the Yellow River in China for more than 50 years and are unique in the world. This study investigated the effect of irrigation practices on the transfer and regional migration mechanisms of nitrate (NO3(-)) in surface water and groundwater in a Yellow River alluvial fan. Hydrochemical indices (EC, pH, Na(+), K(+), Mg(2+), Ca(2+), Cl(-), SO4(2-), and HCO(3-)) and stable isotopic composition (δ18O and δD) were determined for samples. Correlation analysis and principal component analysis (PCA) were performed to identify the sources of water constituents. Kriging was employed to simulate the spatial diffusion of NO3(-) and stable isotopes. Our results demonstrated that the groundwater exhibited more complex saline conditions than the surface water, likely resulting from alkaline conditions and lixiviation. NO3(-) was detected in all samples, 87.0% of which were influenced by anthropogenic activity. The NO3(-) pollution in groundwater was more serious than the common groundwater irrigation areas in the North China Plain (NCP), and was also slightly higher than that in surface water in the study area, but this was not statistically significant (p > 0.05). In addition, the groundwater sites with higher NO3(-) concentrations did not overlap with the spatial distribution of fertilizer consumption, especially in the central and western parts of the study area. NO3(-) distributions along the hydrogeological cross-sections were related to the groundwater flow system. Hydrochemical and environmental isotopic evidences indicate that surface water-groundwater interactions influence the spatial distribution of NO3(-) in the Piedmont of South Taihang Mountains.

  14. Ground-water quality in agricultural areas, Anoka Sand Plain Aquifer, east-central Minnesota, 1984-90

    USGS Publications Warehouse

    Landon, M.K.; Delin, G.N.

    1995-01-01

    Concentrations of atrazine and DEA generally were greater near the water table and decreased or were not detected in deeper wells. All of the samples in which atrazine and DEA were detected also had increased (greater than 3 mg/L) nitrate-N concentrations. However, not all samples with increased concentrations of nitrate-N had detections of atrazine or DEA. This likely indicates either that there were sources of nitrate-N other than cultivated fields on which both atrazine and nitrogen were applied or that nitrate-N reached ground water more readily than atrazine or DEA.

  15. Trend in groundwater quality near FMD burials in agricultural region, South Korea

    NASA Astrophysics Data System (ADS)

    Lim, Jeong-Won; Lee, Kang-Kun

    2015-04-01

    After the nation-wide outbreak of Foot and Mouth Disease (FMD) in winter of 2010-2011, thousands of mass burial site had been built all over the country in Korea. Though the burial pits were partially lined with impermeable material, potential threat of leachate leakage was still in concern. In worry of leachate release from those livestock burials during decomposition of carcasses, groundwater samples from wells near the burials were collected and analyzed in between 2011 and 2013. Among the sample locations, 250 wells with monitoring priorities were chosen and had been watched continuously through the years. For trend analysis of groundwater quality, relations between land use types, distances to burial and nitrate concentrations are studied. Types of land use within 300 m radius of each well were investigated. Nitrate concentrations show proportional relations to the area of agricultural activity and inversely proportional to the area of forest. The proportionality decreased with both agricultural and forest area since 2011. When seasonal variation is concerned, slightly stronger proportionality is shown in dry season for both agricultural and forested area. For a qualitative analysis of the trend, non-parametric Kendall test is applied. Especially, regional Kendall test is implemented to find out spatial feature of nitrate concentration. Nitrate concentrations show slow but statistically significant deceasing trend for every well. When the wells are group according to their distances from the nearest burial pit, decreasing trend of nitrate concentration is shown in all groups. However, there was no consistency in significant factor among the groups. Considering the above mentioned results, the groundwater wells near the burials seem to be influence more from agricultural activities near the wells than from the burial leachate. The slow but significant decreasing trend in nitrate concentration is supposed as the result of an increasing governmental interest in

  16. Agricultural land application of pulp and paper mill sludges in the Donnacona area, Quebec: Chemical evaluation and crop response

    SciTech Connect

    Veillette, A.X.; Tanguay, M.G.

    1997-12-31

    Primary paper mill sludges from a thermomechanical pulp (TMP) mill were land applied at the rate of 20 metric ton per hectare (t/ha) for agricultural purposes in the Donnacona area, Quebec, in May 1994 and May 1995. Eleven agricultural sites featuring various crops were tested over two seasons to measure the impact of TMP primary paper mill sludges on soil, plant tissue and crop yield. Cereal and potato crops showed a significant increase in yield. TMP Primary sludges were also applied at the rate of 225 t/ha for land reclamation purposes of one site at the end of 1994. Soils were tested every second month. Chemical crop analyses were also performed. The first year crop response was satisfactory. Combined (primary and secondary) TMP sludges were added at the rate of 200 t/ha in the beginning of 1996. Soil, vadose zone water and crop analysis are being investigated. Impressive crop responses were obtained in the 1996 season.

  17. Regression models for estimating concentrations of atrazine plus deethylatrazine in shallow groundwater in agricultural areas of the United States

    USGS Publications Warehouse

    Stackelberg, Paul E.; Barbash, Jack E.; Gilliom, Robert J.; Stone, Wesley W.; Wolock, David M.

    2012-01-01

    Tobit regression models were developed to predict the summed concentration of atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine] and its degradate deethylatrazine [6-chloro-N-(1-methylethyl)-1,3,5,-triazine-2,4-diamine] (DEA) in shallow groundwater underlying agricultural settings across the conterminous United States. The models were developed from atrazine and DEA concentrations in samples from 1298 wells and explanatory variables that represent the source of atrazine and various aspects of the transport and fate of atrazine and DEA in the subsurface. One advantage of these newly developed models over previous national regression models is that they predict concentrations (rather than detection frequency), which can be compared with water quality benchmarks. Model results indicate that variability in the concentration of atrazine residues (atrazine plus DEA) in groundwater underlying agricultural areas is more strongly controlled by the history of atrazine use in relation to the timing of recharge (groundwater age) than by processes that control the dispersion, adsorption, or degradation of these compounds in the saturated zone. Current (1990s) atrazine use was found to be a weak explanatory variable, perhaps because it does not represent the use of atrazine at the time of recharge of the sampled groundwater and because the likelihood that these compounds will reach the water table is affected by other factors operating within the unsaturated zone, such as soil characteristics, artificial drainage, and water movement. Results show that only about 5% of agricultural areas have greater than a 10% probability of exceeding the USEPA maximum contaminant level of 3.0 μg L-1. These models are not developed for regulatory purposes but rather can be used to (i) identify areas of potential concern, (ii) provide conservative estimates of the concentrations of atrazine residues in deeper potential drinking water supplies, and (iii) set priorities

  18. Relation of nitrate concentrations in ground water to well depth, well use, and land use in Franklin Township, Gloucester County, New Jersey, 1970-85

    USGS Publications Warehouse

    MacLeod, Cecilia Louise; Barringer, T.H.; Vowinkel, E.F.; Price, C.V.

    1995-01-01

    A water-quality data base was developed to permit the investigation of the relation of concentrations of nitrate (as nitrogen) in ground water to well depth, well use, and land use (agricultural, residential, urban nonresidential, and undeveloped) in Franklin Township. Nitrate concentrations in water from 868 wells tended to decrease with depth. A rank-order regression model of nitrate concen- trations and land-use percentages was fitted to data from 98 shallow domestic wells. The model, which explains about 25 percent of the variance in the data, indicated that nitrate concentration increased with the percentage of developed land in a well's buffer zone. Further stratification of the data based on well use (commercial, domestic, or agricultural/irrigation) indicated that elevated nitrate concentrations were more common in water from agricultural/irrigation wells than in water from domestic or commercial wells. Concentrations of nitrate were indicative of human activities in water from about one-third of the wells sampled but exceeded the U.S. Environmental Protection Agency's maximum contaminant level of 10 milligrams per liter in water from only 1 percent of the wells. A sampling strategy in which water from wells of different depths located within areas in each of the four land-use categories is sampled yearly and analyzed for nitrate and other constituents would facilitate determination of the effects of human activities on ground-water quality.

  19. Impacts on irrigated agriculture of changes in electricity costs resulting from Western Area Power Administration`s power marketing alternatives

    SciTech Connect

    Edwards, B.K.; Flaim, S.J.; Howitt, R.E.; Palmer, S.C.

    1995-03-01

    Irrigation is a major factor in the growth of US agricultural productivity, especially in western states, which account for more than 85% of the nation`s irrigated acreage. In some of these states, almost all cropland is irrigated, and nearly 50% of the irrigation is done with electrically powered pumps. Therefore, even small increases in the cost of electricity could have a disproportionate impact on irrigated agriculture. This technical memorandum examines the impacts that could result from proposed changes in the power marketing programs of the Western Area Power Administration`s Salt Lake City Area Office. The changes could increase the cost of power to all Western customers, including rural municipalities and irrigation districts that rely on inexpensive federal power to pump water. The impacts are assessed by translating changes in Western`s wholesale power rate into changes in the cost of pumping water as an input for agricultural production. Farmers can adapt to higher electricity prices in many ways, such as (1) using different pumping fuels, (2) adding workers and increasing management to irrigate more efficiently, and (3) growing more drought-tolerant crops. This study projects several responses, including using less groundwater and planting fewer waterintensive crops. The study finds that when dependence on Western`s power is high, the cost of power can have a major effect on energy use, agricultural practices, and the distribution of planted acreage. The biggest percentage changes in farm income would occur (1) in Nevada and Utah (however, all projected changes are less than 2% of the baseline) and (2) under the marketing alternatives that represent the lowest capacity and energy offer considered in Western`s Electric Power Marketing Environmental Impact Statement. The aggregate impact on farm incomes and the value of total farm production would be much smaller than that suggested by the changes in water use and planted acreage.

  20. Evaluating Chemical Tracers in Suburban Groundwater as Indicators of Nitrate-Nitrogen Sources

    NASA Astrophysics Data System (ADS)

    Nitka, A.; DeVita, W. M.; McGinley, P.

    2015-12-01

    The CDC reports that over 15 million US households use private wells. These wells are vulnerable to contamination. One of the most common contaminants in private wells is nitrate. Nitrate has a health standard of 10 mg/L. This standard is set to prevent methemaglobinemia, or "blue baby" syndrome, in infants. In extreme cases it can affect breathing and heart function, and even lead to death. Elevated nitrate concentrations have also been associated with increased risk of thyroid disease, diabetes, and certain types of cancer. Unlike municipal wells, there is no mandatory testing of private wells. It is the responsibility of users to have their well water tested. The objective of this research was to identify the most useful chemical tracers for determining sources of nitrate in private water supplies. Chemical characteristics, such as mobility in groundwater and water solubility, as well as frequency of use, were considered when choosing source indicators. Fourteen pharmaceuticals and personal care products unique to human use were chosen to identify wells impacted by septic waste. A bovine antibiotic and five pesticide metabolites were used to identify contamination from agricultural sources. Eighteen private wells were selected in a suburban area with septic systems and adjacent agricultural land. The wells were sampled five times and analyzed to provide a temporal profile of nitrate and the tracers. The artificial sweetener sucralose was found in >70% of private wells. Wells with sucralose detected had nitrate concentrations between 5-15 mg/L. The herbicide metabolite metolachlor ESA was detected in 50% of the wells. These wells typically had the highest nitrate concentrations, often >10 mg/L. The common use and frequent detection of these two compounds made them the most reliable indicators of nitrate sources evaluated in this study. This information will help well owners determine appropriate treatment and remediation options and could direct future

  1. Isotopic compositions and sources of nitrate in ground water from western Salt River Valley, Arizona

    USGS Publications Warehouse

    Gellenbeck, D.J.

    1994-01-01

    Isotopic and chemical compositions of ground water from western Salt River Valley near Phoenix, Arizona, were used to develop identification tech- niques for sources of nitrate in ground water. Four possible sources of nitrate were studied: dairies and feedlots, sewage-treatment plants, agricultural activities, and natural source. End members that represent these sources were analyzed for a variety of chemical and isotopic constituents; contents of the end-member and the ground water were compared to identify nitrate from these sources. Nitrate from dairies and feedlots was identified by delta 15N values higher than +9.0 per mil. Nitrate from sewage treatment plants was identified by some chemical constituents and values of delta 15N, delta 34S, delta 7Li, and delta 11B that were lighter than the values determined for ground water not affected by sewage-treatment plants. Nitrate from agricultural activities was identified by delta 15N, 3H, and delta 34S compositions. Natural nitrate derived from decomposing plants and accumulated by biological fixation was identified by delta 15N values that range between +2 and +8 per mil. In addition to identifying nitrate sources, some chemical and isotopic charabteristics of ground water were determined on the basis of data collected during this study. Concentrations of major ions, lithium, and boron and delta 7Li, delta 11B, 3H, delta D, and delta 18O data identify ground water in different geographic regions in the study area. These differences probably are related to different sources of ground water, geochemical processes, or geologic deposits. The Luke salt body and a geothermal anomaly alter the chemical and isotopic content of some ground water.

  2. System for analysis of LANDSAT agricultural data: Automatic computer-assisted proportion estimation of local areas

    NASA Technical Reports Server (NTRS)

    Nalepka, R. F. (Principal Investigator); Kauth, R. J.; Thomas, G. S.

    1976-01-01

    The author has identified the following significant results. A conceptual man machine system framework was created for a large scale agricultural remote sensing system. The system is based on and can grow out of the local recognition mode of LACIE, through a gradual transition wherein computer support functions supplement and replace AI functions. Local proportion estimation functions are broken into two broad classes: (1) organization of the data within the sample segment; and (2) identification of the fields or groups of fields in the sample segment.

  3. Nitrate contamination risk assessment in groundwater at regional scale

    NASA Astrophysics Data System (ADS)

    Daniela, Ducci

    2016-04-01

    Nitrate groundwater contamination is widespread in the world, due to the intensive use of fertilizers, to the leaking from the sewage network and to the presence of old septic systems. This research presents a methodology for groundwater contamination risk assessment using thematic maps derived mainly from the land-use map and from statistical data available at the national institutes of statistic (especially demographic and environmental data). The potential nitrate contamination is considered as deriving from three sources: agricultural, urban and periurban. The first one is related to the use of fertilizers. For this reason the land-use map is re-classified on the basis of the crop requirements in terms of fertilizers. The urban source is the possibility of leaks from the sewage network and, consequently, is linked to the anthropogenic pressure, expressed by the population density, weighted on the basis of the mapped urbanized areas of the municipality. The periurban sources include the un-sewered areas, especially present in the periurban context, where illegal sewage connections coexist with on-site sewage disposal (cesspools, septic tanks and pit latrines). The potential nitrate contamination map is produced by overlaying the agricultural, urban and periurban maps. The map combination process is very easy, being an algebraic combination: the output values are the arithmetic average of the input values. The groundwater vulnerability to contamination can be assessed using parametric methods, like DRASTIC or easier, like AVI (that involves a limited numbers of parameters). In most of cases, previous documents produced at regional level can be used. The pollution risk map is obtained by combining the thematic maps of the potential nitrate contamination map and the groundwater contamination vulnerability map. The criterion for the linkages of the different GIS layers is very easy, corresponding to an algebraic combination. The methodology has been successfully

  4. Assessing the relationship between groundwater nitrate and animal feeding operations in Iowa (USA)

    USGS Publications Warehouse

    Zirkle, Keith W.; Nolan, Bernard T.; Jones, Rena R.; Weyer, Peter J.; Ward, Mary H.; Wheeler, David C.

    2016-01-01

    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 2 km of a well (p trend < 0.001), number of open AFOs within 5 km of a well (p trend < 0.001), and number of mixed AFOs within 30 km 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 (0.171 log(mg/L), 0.319 log(mg/L), and 0.541 log(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 (> 5 mg/L) compared with low-nitrate (≤ 5 mg/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.

  5. Development and Implementation of Production Area of Agricultural Product Data Collection System Based on Embedded System

    NASA Astrophysics Data System (ADS)

    Xi, Lei; Guo, Wei; Che, Yinchao; Zhang, Hao; Wang, Qiang; Ma, Xinming

    To solve problems in detecting the origin of agricultural products, this paper brings about an embedded data-based terminal, applies middleware thinking, and provides reusable long-range two-way data exchange module between business equipment and data acquisition systems. The system is constructed by data collection node and data center nodes. Data collection nodes taking embedded data terminal NetBoxII as the core, consisting of data acquisition interface layer, controlling information layer and data exchange layer, completing the data reading of different front-end acquisition equipments, and packing the data TCP to realize the data exchange between data center nodes according to the physical link (GPRS / CDMA / Ethernet). Data center node consists of the data exchange layer, the data persistence layer, and the business interface layer, which make the data collecting durable, and provide standardized data for business systems based on mapping relationship of collected data and business data. Relying on public communications networks, application of the system could establish the road of flow of information between the scene of origin certification and management center, and could realize the real-time collection, storage and processing between data of origin certification scene and databases of certification organization, and could achieve needs of long-range detection of agricultural origin.

  6. [Changes of China agricultural climate resources under the background of climate change. IV. Spatiotemporal change characteristics of agricultural climate resources in sub-humid warm-temperate irrigated wheat-maize agricultural area of Huang-Huai-Hai Plain].

    PubMed

    Liu, Zhi-juan; Yang, Xiao-guang; Wang, Wen-feng

    2011-04-01

    Based on the 1961-2007 observation data from 66 meteorological stations in the sub-humid and warm-temperate irrigated wheat-maize agricultural area of Huang-Huai-Hai Plain, this paper analyzed the spatiotemporal change characteristics of agro-climate resources for chimonophilous and thermophilic crops in the area in 1961-1980 and 1981-2007. The analyzed items included the length of temperature-defined growth season and the active accumulative temperature, sunshine hours, precipitation, reference evapotranspiration, and aridity index during the temperature-defined growth season. With climate warming, the length of temperature-defined growth season of chimonophilous and thermophilic crops in the area in 1981-2007 extended by 7. 4 d and 6. 9 d, and the > or = 0 degrees C and > or = 10 degrees C accumulative temperature increased at a rate of 4.0-137.0 and 1.0-142.0 degrees C d (10 a)(-1), respectively, compared with those in 1961-1980. The sunshine hours during the temperature-defined growth season of the crops decreased markedly; and the precipitation during the temperature-defined growing season decreased in most parts of the area, being obvious in Hebei and north Shandong Province, but increased in north Anhui and southeast Henan Province. In most parts of the area, the reference evapotranspiration of chimonophilous and thermophilic crops during their temperature-defined growth season decreased, and the aridity index increased.

  7. An Analysis of "In-Depth" Schools Conducted by Area Extension Agents in the Agricultural Industry.

    ERIC Educational Resources Information Center

    Cunningham, Clarence J.

    The Ohio Extension Service conducted "in-depth" schools on Dairy Genetics and Reproduction, Beef Cattle, Capital Management, and Fertilizer and Lime at area centers in Wooster, Defiance and Fremont, Washington Court House, and McConnellsville. Two thirds of the instructional staff were area agents; others were specialists, resident…

  8. Rainfed Areas and Animal Agriculture in Asia: The Wanting Agenda for Transforming Productivity Growth and Rural Poverty

    PubMed Central

    Devendra, C.

    2012-01-01

    The importance of rainfed areas and animal agriculture on productivity enhancement and food security for economic rural growth in Asia is discussed in the context of opportunities for increasing potential contribution from them. The extent of the rainfed area of about 223 million hectares and the biophysical attributes are described. They have been variously referred to inter alia as fragile, marginal, dry, waste, problem, threatened, range, less favoured, low potential lands, forests and woodlands, including lowlands and uplands. Of these, the terms less favoured areas (LFAs), and low or high potential are quite widely used. The LFAs are characterised by four key features: i) very variable biophysical elements, notably poor soil quality, rainfall, length of growing season and dry periods, ii) extreme poverty and very poor people who continuously face hunger and vulnerability, iii) presence of large populations of ruminant animals (buffaloes, cattle, goats and sheep), and iv) have had minimum development attention and an unfinished wanting agenda. The rainfed humid/sub-humid areas found mainly in South East Asia (99 million ha), and arid/semi-arid tropical systems found in South Asia (116 million ha) are priority agro-ecological zones (AEZs). In India for example, the ecosystem occupies 68% of the total cultivated area and supports 40% of the human and 65% of the livestock populations. The area also produces 4% of food requirements. The biophysical and typical household characteristics, agricultural diversification, patterns of mixed farming and cropping systems are also described. Concerning animals, their role and economic importance, relevance of ownership, nomadic movements, and more importantly their potential value as the entry point for the development of LFAs is discussed. Two examples of demonstrated success concern increasing buffalo production for milk and their expanded use in semi-arid AEZs in India, and the integration of cattle and goats with oil

  9. Rainfed areas and animal agriculture in Asia: the wanting agenda for transforming productivity growth and rural poverty.

    PubMed

    Devendra, C

    2012-01-01

    The importance of rainfed areas and animal agriculture on productivity enhancement and food security for economic rural growth in Asia is discussed in the context of opportunities for increasing potential contribution from them. The extent of the rainfed area of about 223 million hectares and the biophysical attributes are described. They have been variously referred to inter alia as fragile, marginal, dry, waste, problem, threatened, range, less favoured, low potential lands, forests and woodlands, including lowlands and uplands. Of these, the terms less favoured areas (LFAs), and low or high potential are quite widely used. The LFAs are characterised by four key features: i) very variable biophysical elements, notably poor soil quality, rainfall, length of growing season and dry periods, ii) extreme poverty and very poor people who continuously face hunger and vulnerability, iii) presence of large populations of ruminant animals (buffaloes, cattle, goats and sheep), and iv) have had minimum development attention and an unfinished wanting agenda. The rainfed humid/sub-humid areas found mainly in South East Asia (99 million ha), and arid/semi-arid tropical systems found in South Asia (116 million ha) are priority agro-ecological zones (AEZs). In India for example, the ecosystem occupies 68% of the total cultivated area and supports 40% of the human and 65% of the livestock populations. The area also produces 4% of food requirements. The biophysical and typical household characteristics, agricultural diversification, patterns of mixed farming and cropping systems are also described. Concerning animals, their role and economic importance, relevance of ownership, nomadic movements, and more importantly their potential value as the entry point for the development of LFAs is discussed. Two examples of demonstrated success concern increasing buffalo production for milk and their expanded use in semi-arid AEZs in India, and the integration of cattle and goats with oil

  10. Lead in soil and agricultural products in the Huainan Coal Mining Area, Anhui, China: levels, distribution, and health implications.

    PubMed

    Fang, Ting; Liu, Guijian; Zhou, Chuncai; Lu, Lanlan

    2015-03-01

    Heavy metal accumulation in agricultural soil is of great concern, as heavy metals can be finally transferred to the human body through the food chain. A field survey was conducted to investigate the lead (Pb) levels and distribution in soil, agricultural products (wheat, paddy, and soybean), and fish, in the Huainan Coal Mining Area (HCMA), Anhui Province, China, to provide reference information to local inhabitants. The daily intake and target hazard quotients of Pb through food consumption were assessed. Results showed that the mean Pb concentration in soil was higher than the Huainan soil background Pb value but lower than the maximum allowance Pb concentration for agricultural soil (GB 15618-2008). The elevated Pb in soil, especially in rainy months (June to August in Huainan), might be related to Pb leaching from ambient coal gangue piles. Excessive Pb concentration was found in the grains of food crops, which would pose a potential health risk to local inhabitants. Therein, wheat showed higher Pb bioaccumulation ability than other crops. With regard to the Pb levels in muscles, fishes were considered to be safe for consumption. The calculations on daily intake and tolerable hazard quotient of Pb suggest that the potential health hazard posed by Pb is currently insignificant for the inhabitants in the HCMA.

  11. [The allergic risk in agriculture: current situation and specific high-risk areas].

    PubMed

    Previdi, M; Brambilla, G

    2012-01-01

    Contradictory aspects apparently coexist in relation to the causes of bronchial allergic inflammation in agriculture. It's worth notion that either exposure to inhalable dust and endotoxins or exposure to molecular patterns play a role in such a pathology; in particular endotoxins should protect against the onset of allergic diseases. Likewise, the exposure to pesticides would not lead to allergic asthma, but could facilitate the onset of pollinosis and contact dermatitis in gardeners. Moreover, the risk of anaphylaxis from bee sting would be lower in repeatedly bitten beekeepers if compared to sensitized and less exposed population, while atopy by itself is not evaluable as a risk factor for sensitization to hymenoptera. In conclusion either frequency and strength of exposure or distinctive feature of the subject are able to determine the occurrence of allergic disease in an almost different manner.

  12. Modeling land-based nitrogen loads from groundwater-dominated agricultural watersheds to estuaries to inform nutrient reduction planning

    NASA Astrophysics Data System (ADS)

    Jiang, Yefang; Nishimura, Peter; van den Heuvel, Michael R.; MacQuarrie, Kerry T. B.; Crane, Cindy S.; Xing, Zisheng; Raymond, Bruce G.; Thompson, Barry L.

    2015-10-01

    Excessive nitrate loads from intensive potato production have been linked to the reoccurring anoxic events in many estuaries in Prince Edward Island (PEI), Canada. Community-led watershed-based nutrient reduction planning has been promoted as a strategy for water quality restoration and initial nitrate load criteria have been proposed for the impacted estuaries. An integrated modeling approach was developed to predict base flow nitrate loads to inform the planning activities in the groundwater-dominated agricultural watersheds. Nitrate load is calculated as base flow multiplied by the average of nitrate concentration at the receiving watershed outlet. The average of nitrate concentration is estimated as the integration of nitrate leaching concentration over the watershed area minus a nitrate loss coefficient that accounts for long-term nitrate storage in the aquifer and losses from the recharge to the discharge zones. Nitrate leaching concentrations from potato rotation systems were estimated with a LEACHN model and the land use areas were determined from satellite image data (2006-2009) using GIS. The simulated average nitrate concentrations are compared with the arithmetic average of nitrate concentration measurements in each of the 27 watersheds for model calibration and in 138 watersheds for model verifications during 2006-2009. Sensitivity of the model to the variations of land use mapping errors, nitrate leaching concentrations from key sources, and nitrate loss coefficient was tested. The calibration and verification statistics and sensitivity analysis show that the model can provide accurate nitrate concentration predictions for watersheds with drainage areas more than 5 km2 and nitrate concentration over 2 mg N L-1, while the model resolution for watersheds with drainage areas below 5 km2 and/or nitrate concentration below 2 mg N L-1 may not be sufficient for nitrate load management purposes. Comparisons of normalized daily stream discharges among the

  13. Site-specific profiles of estrogenic activity in agricultural areas of California's inland waters.

    PubMed

    Lavado, Ramon; Loyo-Rosales, Jorge E; Floyd, Emily; Kolodziej, Edward P; Snyder, Shane A; Sedlak, David L; Schlenk, Daniel

    2009-12-15

    To evaluate the occurrence and sources of compounds capable of feminizing fish in agriculturally impacted waterways of the Central Valley of California, water samples were extracted and subjected to chemical analyses as well as in vitro and in vivo measurements of vitellogenin in juvenile rainbow trout (Oncorhynchus mykiss). Among the 16 sites sampled, 6 locations frequently exhibited elevated concentrations of estrogenic substances with 17beta-estradiol equivalents up to 242 ng/L in vitro and 12 microg/kg in vivo. The patterns of activity varied among sites, with two sites showing elevated activity only in vitro, two showing elevated activity only in vivo, and two showing elevated activity in both assays. Sequential elution of solid-phase extraction (SPE) disks followed by bioassay-guided fractionation was used to characterize water samples from the two locations where activity was observed in both bioassays. The highest estrogenic activity was observed in the most nonpolar fractions (80-100% methanol eluent) from the Napa River, while most of the activity in the Sacramento River Delta eluted in the 60% methanol eluent. Quantitative analyses of SPE extracts and additional HPLC fractionation of the SPE extracts by GC-MS/MS and LC-MS/MS indicated concentrations of steroid hormones, alkylphenol polyethoxylates, and herbicides that were at least 1-3 orders of magnitude below bioassay 17beta-estradiol equivalent calculations. Given the different patterns of activity and chemical properties of the estrogenic compounds, it appears that estrogenic activity in these agriculturally impacted surface waters is attributable to multiple compounds. Further investigation is needed to identify the compounds causing the estrogenic activity and to determine the potential impacts of these compounds on feral fish.

  14. Nitrate in groundwater and N circulation in eastern Botswana

    NASA Astrophysics Data System (ADS)

    Lagerstedt, E.; Jacks, G.; Sefe, F.

    1994-02-01

    Nitrate pollution due to deep leaching from pit latrines has caused water supply wells in eastern Botswana to exceed health limits concerning nitrate. It was deduced from the estimated intake of salt and protein by the population that, as an average, about 10 percent of the human nitrogen excretion is leached to the groundwater. This fraction was also found in southern India, where on-the-ground excretion is customary. The nitrogen circulation in general in the savanna ecosystem is not appreciably affected in spite of a large livestock density. Overall nitrate leaching is in the order of 1.5 kg N/ha/y, similar to that in another semiarid area in southern India. However, in India, there seems to be a more diffuse areal leaching from agriculture as well as from villages. Measures to minimize the nitrate leaching could be to plant deep-rooted trees adjacent to pit latrines or to use latrines that separate the urine from the faces for a more near-surface infiltration facilitating plant uptake. Measures to minimize leaching will also lessen the rick for bacterial pollution of the groundwater.

  15. Factors affecting attitudes toward care of elderly mothers: urban versus agricultural areas.

    PubMed

    Ohta, Mio; Kai, Ichiro

    2010-01-01

    In our previous study, we examined factors that affect rural people's attitudes toward parental care when their mothers or mothers-in-law become fragile and need 24-h care. Our next task was to examine the factors in an urban area to test external validity. In the previous studies, several factors affecting adult children's attitudes between caring directly for parents or sending parents to a nursing home were indicated. Factors identified included affection, filial obligation, sekentei (i.e., wanting to keep an appearance of taking care), and others. In this study, we examine these factors in a residential urban area, using the same model as before. Results revealed that filial obligation affected attitudes toward care in the case of a mother while affection did in the case of a mother-in-law. This is consistent with the results in the rural setting. Sekentei did not affect attitudes in the urban area, though it had in the rural area.

  16. Nitrate isotopes unveil distinct seasonal N-sources and the critical role of crop residues in groundwater contamination

    NASA Astrophysics Data System (ADS)

    Savard, Martine M.; Somers, George; Smirnoff, Anna; Paradis, Daniel; van Bochove, Eric; Liao, Shawna

    2010-02-01

    SummaryGlobally, fertilizers are identified as principle sources of nitrate in waters of intensely cultivated areas. Here this general concept is appraised on a seasonal basis over a two year period, under temperate climatic conditions. Water ( δ2H and δ18O) and nitrate ( δ15N and δ18O) isotopes in surface water and groundwater suggest that freshwater is acting as a transport vector conducting nitrate from agricultural soils to groundwater and ultimately to surface water. Measured nitrate isotopes of organic and inorganic fertilizers and of nitrate in groundwater are used to constrain a conceptual apportionment model quantifying the relative seasonal N contributions in an area of intense potato production. Source inputs differ strongly between the growing (summer and fall) and non-growing (winter and spring) periods. Chemical fertilizers and soil organic matter equally dominate and contribute to the growing period load, whereas soil organic matter dominates the non-growing period load, and accounts for over half of the overall annual nitrogen charge. These findings reveal the magnitude of nitrogen cycling by soil organic matter, and point to the benefits of controlling the timing of its nitrate release from this organic material. We conclude that strategies to attenuate contamination by nitrate in waters of temperate climate row-cropping regions must consider nitrogen cycling by soil organic matter, including the crucial role of crop residues throughout both the growing and non-growing seasons.

  17. Oxygenated, nitrated, methyl and parent polycyclic aromatic hydrocarbons in rivers of Haihe River System, China: occurrence, possible formation, and source and fate in a water-shortage area.

    PubMed

    Qiao, Meng; Qi, Weixiao; Liu, Huijuan; Qu, Jiuhui

    2014-05-15

    Substituted polycyclic aromatic hydrocarbons (SPAHs) occur ubiquitously in the whole global environment as a result of their persistence and widely-spread sources. Some SPAHs show higher toxicities and levels than the corresponding PAHs. Three types of most frequently existing SPAHs, oxygenated-PAHs (OPAHs), nitrated-PAHs (NPAHs), and methyl-PAHs (MPAHs), as well as the 16 priority PAHs were investigated in this study. The purpose was to identify the occurrence, possible transformation, and source and fate of these target compounds in a water shortage area of North China. We took a river system in the water-shortage area in China, the Haihe River System (HRS), as a typical case. The rivers are used for irrigating the farmland in the North of China, which probably introduce these pollutants to the farmland of this area. The MPAHs (0.02-0.40 μg/L in dissolved phase; 0.32-16.54 μg/g in particulate phase), OPAHs (0.06-0.19 μg/L; 0.41-17.98 μg/g), and PAHs (0.16-1.20 μg/L; 1.56-79.38 μg/g) were found in the water samples, but no NPAHs were detected. The concentrations of OPAHs were higher than that of the corresponding PAHs. Seasonal comparison results indicated that the OPAHs, such as anthraquinone and 2-methylanthraquinone, were possibly transformed from the PAHs, particularly at higher temperature. Wastewater treatment plant (WWTP) effluent was deemed to be the major source for the MPAHs (contributing 62.3% and 87.6% to the receiving river in the two seasons), PAHs (68.5% and 89.4%), and especially OPAHs (80.3% and 93.2%) in the rivers. Additionally, the majority of MPAHs (12.4 kg, 80.0% of the total input), OPAHs (16.2 kg, 83.5%), and PAHs (65.9 kg, 93.3%) in the studied months entered the farmland through irrigation.

  18. Modeled nitrate levels in well water supplies and prevalence of abnormal thyroid conditions among the Old Order Amish in Pennsylvania

    PubMed Central

    2012-01-01

    Background Nitrate is a widespread contaminant of drinking water supplies, especially in agricultural areas. Nitrate intake from drinking water and dietary sources can interfere with the uptake of iodide by the thyroid, thus potentially impacting thyroid function. Methods We assessed the relation of estimated nitrate levels in well water supplies with thyroid health in a cohort of 2,543 Old Order Amish residing in Lancaster, Chester, and Lebanon counties in Pennsylvania for whom thyroid stimulating hormone (TSH) levels were measured during 1995-2008. Nitrate measurement data (1976-2006) for 3,613 wells in the study area were obtained from the U.S. Geological Survey and we used these data to estimate concentrations at study participants' residences using a standard linear mixed effects model that included hydrogeological covariates and kriging of the wells' residuals. Nitrate levels estimated by the model ranged from 0.35 mg/L to 16.4 mg/L N-NO3-, with a median value of 6.5 mg/L, which was used as the cutpoint to define high and low nitrate exposure. In a validation analysis of the model, we calculated that the sensitivity of the model was 67% and the specificity was 93%. TSH levels were used to define the following outcomes: clinical hyperthyroidism (n = 10), clinical hypothyroidism (n = 56), subclinical hyperthyroidism (n = 25), and subclinical hypothyroidism (n = 228). Results In women, high nitrate exposure was significantly associated with subclinical hypothyroidism (OR = 1.60; 95% CI: 1.11-2.32). Nitrate was not associated with subclinical thyroid disease in men or with clinical thyroid disease in men or women. Conclusions Although these data do not provide strong support for an association between nitrate in drinking water and thyroid health, our results do suggest that further exploration of this hypothesis is warranted using studies that incorporate individual measures of both dietary and drinking water nitrate intake. PMID:22339761

  19. Characterization of nitrate contamination in groundwater in Gosan, western part of Jeju Island

    NASA Astrophysics Data System (ADS)

    Koh, E.; Kaown, D.; Kang, B.; Oh, S.; Moon, H.; Lee, K.

    2010-12-01

    Jeju Isalnd, composed of porous volcanic rocks, is located about 140 km south of the Korean peninsula. The annual mean rainfall of the island (1,975 mm) is about 600 mm higher than that of Korean mainland. Groundwater in Jeju Island is vulnerable to contamination sources in surface land because surface water easily percolates into groundwater when the rainfall event occurs. The western part of the island, where proportion of agricultural area is higher, nitrate contamination in groundwater has been observed. It is important to characterize nitrate contamination in the western part of the island to preserve the groundwater resources. In Gosan, located in the western part of Jeju Island, agricultural fields are broadly distributed resulting from readjustment of arable land in 1970s. Shallow perched groundwater is observed at the top soil layer with depth to water table range of 0.25 ~ 2.68. The nitrate-nitrogen concentration of the shallow groundwater is observed as 8.24 ~ 59.96 mg/l. The deep groundwater is distributed with depth to water table from 12.47 m to 29.11 m and the nitrate-nitrogen concentration is distributed between 0.10 ~ 29.16 mg/l. Such high concentrations of nitrate-nitrogen in the shallow groundwater might cause continuous nitrate contamination of deep groundwater in the study area. Analysis of stable isotope, δ 15N and δ18O of nitrate, in both shallow and deep groundwater was conducted to identify sources of nitrate and transformation processes of nitrogen. Shallow groundwater has broad ranges of δ 15N and δ18O values (δ 15N: 2.3 ~ 26.1‰, δ18O: 2.5 ~ 15.8‰) contrast to deep groundwater, which has limit ranges (δ 15N: 3.1 ~ 5.0‰, δ18O: 0.5 ~ 4.7‰). The source of nitrate in the deep groundwater was identified as the ammonium fertilizer and organic soil and in the shallow groundwater, complex source such as chemical fertilizer, organic soil and denitrification was consider to affect the nitrate contamination in the study area.

  20. Nitrate in ground water in the Great Valley carbonate subunit of the Potomac River Basin

    USGS Publications Warehouse

    Ferrari, Matthew J.; Ator, Scott W.

    1995-01-01

    Agriculture is the major land use in the carbonate part of the Great Valley of the Potomac River Basin. Applied fertilizer and manure are potential sources of nitrate that can contaminate Groundwater. Nitrate concentrations in Groundwater increased with increasing percentage of cropland but did not decrease with increasing well depth, as has been found in previous studies elsewhere. Samples from 28 wells contained nitrate concentrations ranging from 0.29 to 29 mg/L (milligrams per liter) as nitrogen, with a median concentration of 4.55 mg/L, compared to a median of 1.8 mg/L for 1,056 Groundwater samples from the entire Potomac River Basin. Median nitrate concentrations in Groundwater samples were higher in the Maryland, Pennsylvania, and West Virginia part of the valley, and were lower in the Virginia part (7.45 and 2.95 mg/L, respectively), probably as a result of differences in agricultural la