bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphate Availability and Inorganic Transformation in an Alum Sludge‐Affected Soil
Authors: Cox A. E. , Camberato J. J. , Smith B. R. 
Published: July 2010

AbstractLand application of alum sludge is a disposal alternative. A greenhouse experiment was conducted to determine (i) alum sludge effects on phosphorus (P) availability and inorganic P forms, and (ii) the relationship between inorganic P fractions and P availability. Alum sludge slurry (0, 4.45, 8.9, and 17.8 g solid kg−1 soil) was surface applied to wheat (Triticum aestivum L.) grown in a Yauhannah soil (fine‐loamy, siliceous, thermic Aquic Hapludults) at four P rates (0, 6.5, 11, and 22 mg kg−1 soil). After the first wheat crop, the sludge was mixed throughout the soil and a second crop grown. Surface‐applied sludge decreased wheat dry matter (DM) and P uptake. When incorporated, 4.45 g kg−1 alum decreased DM and P uptake. Phosphate application increased DM and P uptake of the first wheat crop, but had no effect on the second crop. Surface‐applied sludge increased Al‐P, Fe‐P, and Ca‐P in the 0‐ to 7.5‐cm soil depth, but not in the 7.5‐ to 15‐cm soil depth. Loosely boond‐P and Al‐P increased with P rate. Phosphorus uptake and DM of the first wheat crop were positively related to loosely bound‐P and Mehlich 1‐P. Dry matter of the second wheat crop was positively related to loosely bound‐P and Mehlich 1‐P and P uptake was positively related to loosely bound‐P. Aluminum‐P was negatively related to P availability indices. In alum sludge‐affected soils applied P is immobilized mainly as Al‐P, and Mehlich 1‐P and loosely boond‐P are reliable estimators of P availability.
Solid‐Phase Extraction of Aldicarb and its Metabolites from Water and Soil
Authors: Johnson K. A. , Harper F. D. , Weisskopf C. P. 
Published: July 2010

AbstractExtraction methods using solid‐phase extraction (SPE) cartridges are generally preferred over traditional liquid‐liquid extraction methods when they are available. Solid‐phase extraction methods require less preparative work, thus increasing sample through‐put. A SPE method using a graphite carbon sorbent was developed to extract low concentrations (1–40 µg/L) of the polar pesticide, aldicarb [2‐methyl‐2‐(methylthio)propionaldehyde O‐(methylcarbamoyl) oxime], and its oxidative metabolites, aldicarb sulfoxide [2‐methyl‐2‐(methylsulfinayl)propionaldehyde‐O‐(methylcarbamoyl) oxime] and aldicarb sulfone [2‐methyl‐2‐(methylsulfonyl) propionaldehyde‐O‐(methylcarbamoyl) oxime] from water samples. The analytes were removed from a 150‐mL water sample by the SPE cartridge and eluted with 2 mL of methanol. Recoveries from water for all three compounds exceeded 90% with coefficients of variation ranging from 3 to 9%. An extraction method was also developed to extract aldicarb and its metabolites from soil using water as the extractant. The analytes are then recovered from the water using the same SPE method referred to above. Recoveries from soil for all three compounds ranged from 80 to 95%. Our SPE method also worked well (recoveries >95%) for two other carbamates, methomyl [S‐methyl N‐[(methylcarbamoyl)oxy]thioacetimidate] and oxamyl [N′, N′‐dimethyl‐N‐[(methylcarbamoyl)oxy]‐1‐thiooxamimidate] tested and should work with other polar compounds once they are in the aqueous phase.
Time Dependency of Triticonazole Fungicide Sorption and Consequences for Diffusion in Soil
Authors: Beigel C. , Barriuso E. , Di Pietro L. 
Published: July 2010

AbstractDiffusion is a key process regarding the redistribution in soils of systemic pesticides applied in seed treatments. We investigated the influence of nonequilibrium sorption on the diffusivity of triticonazole fungicide [(1RS)‐(E)‐5‐(4‐chlorophenyl‐methylen)‐2,2‐dimethyl‐1‐(1H‐1,2,4‐triazol‐1‐ylmethyl)‐cyclopentan‐1‐ol] in loam clay soil from Grignon, France (Typic Eutrochrept). Triticonazole diffusion coefficients were measured in saturated soil columns for time periods ranging from 1 to 25 d. Nonequilibrium sorption was evaluated from measurement of apparent desorption coefficients, and from estimation of apparent partition coefficients from a diffusivity model. Triticonazole availability was also evaluated based on successive aqueous and methanol extractions, and measurement of the nonextractable residues fraction. Triticonazole diffusion in soil was characterized by a strong time‐dependence. Apparent diffusion coefficient decreased from 0.05 cm2 d−1 at 2 d to 0.02 cm2 d−1 at 25 d. Triticonazole apparent sorption coefficient increased with time of diffusion, from 5 L kg−1 at 1 d to 10.5 L kg−1 at 25 d, which was greater than the batch equilibrium value of 4.35 L kg−1. The measured and calculated results were very close, showing that nonequilibrium sorption was the key process responsible for the decrease in triticonazole apparent diffusion rate. The availability of the diffusing residues diminished constantly with time. The water‐extractable fraction corresponding to the more available residues decreased from 31% at 1 d to 17% at 25 d, while a resistant fraction was rapidly formed representing 9% after 25 d. Triticonazole slow desorption behavior was attributed to rate‐limiting intrasorbent diffusion.
Rain Pattern and Soil Moisture Content Effects on Atrazine and Metolachlor Losses in Runoff
Authors: Zhang X. C. , Norton L. D. , Hickman M. 
Published: July 2010

AbstractHerbicide concentration in runoff varies dramatically within a storm, therefore storm pattern is postulated to have a significant impact on herbicide loss. We evaluated the effects of storm pattern and soil moisture content on herbicide loss in runoff, and used our data to validate the uniform mixing concept for modeling herbicide transfer to runoff. Atrazine and metolachlor were surface applied to air‐dried soil at rates of 1.12 and 2.24 kg/ha, respectively. Two soils (Cecil sandy loam and Miami silty loam), four storm patterns (uniform, advanced peak, intermediate peak, and delayed peak), and two moisture levels (wet and dry) were used. Dissolved herbicide losses from the advanced peak were twice those from the other patterns for both herbicides for Cecil soil. The significance of rain pattern effects was reduced for Miami soil, but metolachlor loss from the advanced peak was 1.9 times that from the delayed peak. Rain pattern affected sediment‐bound herbicide loss, but no consistent trend was shown for both soils. Under wet conditions a greater potential for dissolved and sediment‐bound herbicide losses was shown for both herbicides on Miami soil than on Cecil soil. Measured herbicide concentrations in runoff decreased exponentially with cumulative rainfall depth, and were adequately described by the uniform mixing model. Results show that information on intensity distribution and transient infiltration rate is needed to better predict both instantaneous and total herbicide losses during a storm.
Influence of Buffers on Pesticide and Nutrient Runoff from Bermudagrass Turf
Authors: Cole J. T. , Baird J. H. , Basta N. T. , Huhnke R. L. , Storm D. E. , Johnson G. V. , Payton M. E. , Smolen M. D. , Martin D. L. , Cole J. C. 
Published: July 2010

AbstractBuffer length (0, 2.4, and 4.9 m), mowing height (1.3 and 3.8 cm), and solid‐tine aerification were evaluated to reduce pesticide and nutrient runoff from bermudagrass [Cynodon dactylon (L.) Pers.] turf on a Kirkland silt loam (fine, mixed, thermic Udertic Paleustolls) with a 6% slope. Nitrogen, P, chlorpyrifos [o,o‐diethyl o‐(3,5,6‐trichloro‐2‐pyridinyl) phosphorothioate], and the dimethylamine salts of 2,4‐D (2,4‐dichlorophenoxyacetic acid), mecoprop [2‐(2‐methyl‐4‐chlorophenoxy) propionic acid], and dicamba (3,6‐dichloro‐o‐anisic acid) were applied at standard use rates on plots located upslope of buffers. A portable rainfall simulator applied precipitation rates of 51 or 64 mm h−1 for 75 to 140 min within 24 h after chemical application. Soil moisture before simulated rainfall in July 1995 was low and pesticide and nutrient loss to surface runoff was <3% and 2% of applied, respectively. Highest concentrations of pesticides and nutrients in runoff water were 314 µg L−1 for 2,4‐D and 9.57 mg L−1 for PO4‐P from the treatment containing no buffer. In August, 165 mm of natural rainfall fell 7 d before simulated rainfall and pesticide and nutrient loss to surface runoff was increased to 15 and 10% of applied, respectively. Highest concentrations of pesticides and nutrients in runoff water were 174 µg L−1 for 2,4‐D and 8.14 mg L−1 for PO4‐P from the treatment containing no buffer. Overall, buffers were effective in reducing pesticide and nutrient runoff due in part to dilution. In most instances, buffer mowing height, length (2.4 vs. 4.9 m), and aerification did not significantly affect pesticide and nutrient runoff.
Predicting Nitrate Concentrations in Northern Ireland Rivers Using Time Series Analysis
Authors: Stronge K. M. , Lennox S. D. , Smith R. V. 
Published: July 2010

AbstractLough Neagh is an important natural resource, being the largest single source of potable water for Belfast. Its catchment area covers about one‐third of the land area of Northern Ireland. Six inflow rivers drain 88% of the total catchment, which has a land usage of grassland and rough grazing that is similar to Northern Ireland as a whole. This report examines the causes of the year‐to‐year variation in river NO−3 concentrations that have been the focus of European Community (EC) legislation. A multiple regression model has been developed which explains 74% of the variation in NO−3 concentrations for the time period 1974 to 1994. Based on a knowledge of the Northern Ireland annual utilized metabolizable energy (UME) for grazing livestock and N fertilizer sales, the model employs the efficiency of fertilizer usage as an independent variable. Additional independent variables are climatic: previous summer rainfall, sun hours in the winter and rainfall for the period January to June. Based on a worst case scenario, employing the extreme values for these climatic variables and the least fertilizer efficiency ratio, the predicted NO−3 concentration is only 4.4 mg N L−1, which is well below the EC maximum admissible level of 11.3 mg N L−1 for drinking water.
Seasonal and Long‐Term Changes in Nitrate‐Nitrogen Content of Well Water in Oklahoma
Authors: Phillips S. B. , Raun W. R. , Johnson G. V. 
Published: July 2010

AbstractTo ensure that NO3‐N concentrations in groundwater do not exceed the maximum contaminant level (MCL; 10 mg L−1), drinking water supplies are continuously sampled and analyzed. Water sampling and analytical methods have changed during the past 40 yr, and failure to apply the errors associated with those methods places researchers at risk of reporting invalid NO3‐N changes. The objectives of this research were to compare analytical procedures, seasonal samplings, and storage methods for well water NO−3N analyses using historical and recent well water data, to identify where changes in NO3‐N concentration have taken place and possible reasons for the changes; and to determine if age of water, well depth, and NO3‐N concentration are related. Benchmark NO3‐N analyses were obtained for 46 water wells which were then sampled each season (fail, winter, spring, and summer) over a 2‐yr period. For each sampling, four samples were taken from each well; two were frozen immediately (common today) and two were stored at ambient temperature (benchmark procedure). Nitrate‐N was determined on subsamples from all four samples using phenoldisulfonic acid (benchmark procedure) and automated Cd reduction (common today). This work suggests that a minimum difference of 6.15 mg NO3‐N L−1 is required before declaring significant differences between historical and current well water NO3‐N levels.
Acid‐Base Properties of a Limed Pyritic Overburden during Simulated Weathering
Authors: Doolittle James J. , Hossner L. R. 
Published: July 2010

AbstractSurface‐mine reclamation is often hindered by the formation of acid minesoil and acid mine drainage from FeS2 oxidation. Surface soils containing FeS2 are often treated with crushed limestone (predominately CaCO3) to prevent acid minesoil formation. The main objective of this study was to evaluate the long‐term effectiveness of liming pyritic minesoil to prevent the formation of acid minesoil and acid mine drainage. Pyritic minesoils that did not receive lime became acidic very rapidly and produced acidic leachate. Almost all of the FeS2 in this treatment oxidized during the first 200 d. The addition of lime at a rate of 25% of the theoretical acid‐base account (ABA) significantly slowed FeS2 oxidation, but rapid oxidation ensued after the added lime was neutralized. Treatments receiving a liming rate of 50% ABA or greater remained neutral to alkaline throughout the study. Acid‐base values and residual FeS2‐CO3 data, however, indicate that the lime was dissolving from the system faster than the FeS2 was oxidizing, and all the treatments would eventually become acidic. The results indicate that the liming of a pyritic overburden to an ABA of 125% is not a sustainable solution to preventing acid minesoil and acid mine drainage.
Characterization of Volatile Organic Emissions and Wastes from a Swine Production Facility
Authors: Zahn J. A. , Hatfield J. L. , Do Y. S. , DiSpirito A. A. , Laird D. A. , Pfeiffer R. L. 
Published: July 2010

AbstractAnalytical methods for monitoring the volatile organic compound (VOC) emissions, for defining atmospheric transport coefficients, and for monitoring solution phase chemistry have been developed to define processes regulating emission of malodorous and other VOCs from a high odor swine production facility. Of the 40 organic compounds identified in liquid and outdoor air samples from the swine production facility, 27 VOCs were confirmed to contribute to decreased air quality in the vicinity of the facility. Specifically, C2 through C9 organic acids demonstrated the greatest potential for decreased air quality, since these compounds exhibited the highest transport coefficients and highest airborne concentrations. Flux measurements suggested that the total rate of nonmethane VOC emissions from the deep basin swine waste storage system was 500‐ to 5700‐fold greater than established nonmethane VOC fluxes from nonanthropogenic sources. The volatilization rate of malodorous and other VOCs from the stored swine waste was positively correlated with wind velocity between 0.2 and 9.4 m s−1, and a maximum concentration of VOCs present in the air was observed to occur at a wind velocity of 3.6 m s−1. Experimental Henry's law coefficients adequately predicted the transport efficiency observed for some of the VOC emissions measured from air samples taken at 0, 25, and 100 m from the swine waste storage basin; however, results indicated that laboratory‐based extraction procedures, currently used to estimate malodor potential for swine slurry samples, provide an inaccurate representation of malodorous and other airborne VOCs actually present in the air near swine production facilities.
Sewage Biosolids Cumulative Effects on Extractable‐Soil and Grain Elemental Concentrations
Authors: Barbarick K. A. , Ippolito J. A. , Westfall D. G. 
Published: July 2010

AbstractWhile land application of sewage biosolids is the most expedient method of recycling plant nutrients, concern over trace element additions resulted in U.S. Environmental Protection Agency (USEPA) beneficial‐use regulations. We studied 11‐yr biosolids addition effects on ammonium bicarbonate diethylenetriaminepentaacetic acid (AB‐DTPA) and 4 M HNO3 extractable levels of soil Cd, Cu, Mo, Ni, P, Pb, and Zn, and the relationship between the soil‐extractable concentrations and grain concentrations. The soils at our four dryland wheat (Triticum aestivum L.) sites were Aridic Paleustolls (Weld and Platner loam). For each application, we used four rates of biosolids (0, 7, 14, and 28 Mg ha−1) from the Littleton/Englewood, CO Wastewater Treatment Plant. We tested linear, quadratic, and either exponential‐rise (plateau) or exponential‐decay models for AB‐DTPA‐ and 4 M HNO3‐extractable concentrations compared with the cumulative quantity of biosolids‐borne element added and with elemental grain concentrations. Models for AB‐DTPA‐extractable Cu, P, Pb, and Zn and 4 M HNO3‐extractable Cu and P vs. the cumulative quantity added produced R2 values ≥ 0.46. For grain concentrations, only the models for AB‐DTPA vs. grain Zn produced an R2 ≥ 0.50. For monitoring soil levels of Cd, Cu, Mo, Ni, P, Pb, and Zn in Paleustolls (common soils in the western Great Plains dryland wheat areas) that continuously receive biosolids, we recommend AB‐DTPA over 4 M HNO3 soil extractions. The AB‐DTPA extractions also provide soil fertility information (NO3‐N and plant available P, K, and micronutrients).
Changes in the Distribution of Selenium Oxidation States with Sample Storage
Authors: Martens D. A. , Suarez D. L. 
Published: July 2010

AbstractSignificant changes in the distribution of selenium (Se) oxidation states of fresh soil were noted with oven‐drying (90°C) or with outdoor storage (>5 yr) in compromised plastic containers compared with small changes in Se oxidation state distribution in air‐dried samples. Compromised outdoor storage resulted in a 25% increase in the selenate (Se6+) concentrations with a concomitant 18.4 and 5.7% decrease in elemental Se and selenite (Se4+) concentrations, respectively, on a total Se basis. Substantial increases in phosphate‐soluble selenide from 15.7% of total Se for fresh seleniferous alfalfa (Medicago sativa L.) to 32.6% phosphate‐soluble Se were noted with air‐dried alfalfa. The results indicate that air‐drying will not substantially alter the distribution of soil Se oxidation states, but will result in a significant increase in the concentration of phosphate‐soluble Se in seleniferous alfalfa residue.
Leaching and Preferential Flow of Clopyralid under Irrigation: Field Observations and Simulation Modeling
Authors: Elliott J. A. , Cessna A. J. , Best K. B. , Nicholaichuk W. , Tollefson L. C. 
Published: July 2010

AbstractPesticide leaching is a potential problem on irrigated land in Saskatchewan. This study examined a worst case scenario for leaching of the herbicide, clopyralid. Herbicide concentrations were measured in water samples from suction lysimeters and tile drain effluent during and after a leaching irrigation to remove salts. Clopyralid was found throughout the soil profile within 20 d of application and was detected in the first water flowing in the tile drains. Approximately 1.5% of the applied clopyralid was lost in the tile drain effluent. The presence of higher concentrations of clopyralid in tile drain water samples at 2 m than in lysimeter water samples taken from 1.5 and 1.8 m was attributed to preferential transport. Another indication of preferential flow was the disparity between measured soil hydraulic characteristics and the timing of the arrival of water in the tile drains. Good agreement between observed and simulated clopyralid distributions was obtained using a bimodal flow scenario with the LEACHM model. It assumed that 40% of the applied water moved through preferential flowpaths with saturated hydraulic conductivities two orders of magnitude greater than the bulk soil. Chemical moving with this water did not penetrate the soil matrix and was not accessed by suction lysimeters. The remaining 60% of applied water moved through the soil matrix according to measured hydraulic characteristics. The modeling approach described herbicide concentrations in the soil matrix and preferential flow from a large field integrated by tile drainage but would not be applicable in soil column studies or small plots.
Phosphate and Tritium Transport through Undisturbed Subsoil as Affected by Ionic Strength
Authors: Jensen Marina Bergen , Hansen Hans Christian Bruun , Hansen Søren , Jørgensen Peter Rene , Magid Jakob , Nielsen Niels Erik 
Published: July 2010

AbstractStorm flow can cause serious subsurface losses of dissolved orthophosphate from soils that under low flow conditions effectively retain orthophosphate (Pi). To test if storm flow loss of Pi can be related to preferential flow and/or decrease in ionic strength of mobile solution we applied combined pulses of H232PO−4 (32p) and tritium (3H2O) to an undisturbed column of clayey subsoil (diam. 0.5 m, height 0.73 m) subjected to water saturated steady flow with either distilled water (0.003 mS cm−1) or a dilute salt solution (0.2 mS cm−1). The pulse applications resulted in narrow breakthroughs of 32P with peak arrivals after displacement of only 2 to 4% of the total water content. In comparison, the 3H2O‐breakthrough curves had peak arrivals after displacement of 8 to 18% of the total water content and showed extensive tailing. In distilled water approximately twice as much phosphate was transported through the column than in the diluted salt solution, although the recovery percentage in both cases was <1% of the applied 32P‐mass. Slicing of the column after dye application confirmed the presence of heterogeneous flow paths. The results suggest that the positive correlation observed between concentration of dissolved Pi and field effluent discharge rate is restricted to rainfall intensities that initiate preferential flow, and that the Pi‐transport is increased the more dilute the percolating solution remains.
Kinetic Isotope Effects in Production of Nitrite‐Nitrogen and Dinitrogen Gas during In Situ Denitrification
Authors: Bates H. K. , Martin G. E. , Spalding R. F. 
Published: July 2010

AbstractIn multistep redox reactions, stable isotopes of the product species can provide insight into the complexities of the reaction. A method was developed that chromatographically separated nitrite (NO−2) from nitrate (NO−3) in quantities that permitted isotopic analysis both N species. Only a 3% peak‐to‐peak crossover contamination was measured in the column eluates during chromatographic separation using 15N‐enriched NO−2. During in situ microcosm‐amended denitrification, low δ15N values of NO−2 ranging from −2 to 4‰ verified that NO−2 produced early persisted throughout much of the reaction. Significant isotopic depletion of the residual NO−3 plus NO−2 fraction resulted. This depletion effect was reflected in lower apparent isotopic‐enrichment factors (flatter slopes) in plots of δ15N vs. In [NO−3 + NO−2] than those vs. In [NO−3] alone. Dinitrogen concentrations produced during the reaction were determined by measuring δAr/N2 values and showed that significant N2 losses occurred in the latter part of the reaction due to supersaturated conditions. The δ15N values for the N2 produced during denitrification ranged from −5.2‰ to higher values of +17‰ when the reaction was ∼70% complete. A slope reversal in δ15N of produced N2 followed when NO−2 reduction became more dominant, as isotope dilution of product N2 occurred. At the culmination of the reaction, the δ15N value of N2 approached but did not return to the original δ15N value of the NO−3. The results caution the blind use of Ar/N2 ratios in groundwaters that initially contain high NO−3 levels and emphasize the importance of NO−2 in environmental sampling.