bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrous Oxide Evolution from Irrigated Land
Authors: Ryden J. C. , Lund L. J. 
Published: July 2010

AbstractNitrous oxide (N2O) fluxes from irrigated land cropped to vegetables in a coastal valley in California ranged from 0.0038 to 1.06 kg N/ha per day. For all sites, maximum fluxes (0.24 to 1.06 kg N/ha per day) were observed during the first post‐fertilization irrigation and were followed by a trend to lower values (0.048 to 0.144 kg N/ha per day) towards the end of cropping despite total fertilizer N inputs of 176 to 528 kg N/ha. The N2O flux showed a pronounced dependence on irrigation events with maximum fluxes associated with soil‐moisture contents between 18 and 22% and soil‐water suctions between 75 and 150 mbars. The magnitude of N2O flux during periods of high moisture content appeared to depend primarily upon soil nitrate concentration which declined during the cropping cycle. Data for N2O flux, soil moisture content, air‐filled porosity, and soil‐water suction suggested that denitrification rather than nitrification was the major process involved in N2O production at each field site. Mean N2O fluxes for each site coupled with soil‐water suction data for a 12‐month period suggested annual emissions of N2O ranging from 19.6 to 41.8 kg N/ha.
Mercury Accumulation in Fish and Invertebrates of the North Fork Holston River, Virginia and Tennessee
Authors: Hildebrand Stephen G. , Strand Rodney H. , Huckabee John W. 
Published: July 2010

AbstractWe investigated both total and methylmercury accumulation in fish and invertebrates in the North Fork of the Holston River below a currently inactive chloralkali plant (i) to quantify the extent of contamination, (ii) to determine what proportion of the variance in mercury concentration in fish can be explained by mercury concentration in water, sediment, benthic invertebrates, and (iii) to determine what proportion of mercury concentration in benthic invertebrates can be explained by mercury concentration in water and sediment. Fish species [rock bass (Ambloplites rupestris) and hog sucker (Hypentelium nigricans)] and benthic invertebrates were collected from stations above and below the plant, and axial muscle (fish) or whole animal (invertebrates) was analyzed for total mercury by flameless atomic absorption and for methylmercury by gas chromatography. The relation of total mercury concentration to fish weight and factors affecting mercury concentration in fish and invertebrates were examined through regression analysis.Total mercury concentration in fish and benthic invertebrates decreased with distance below the plant. Significant linear regressions of total mercury concentration on fish weight were observed for some, but not all, samples examined. Mercury in the methyl form comprised 91.7% of total mercury in fish analyzed, while approximately 50% of the mercury in invertebrates was methylmercury.Multiple regression analysis indicated 96.4% of the variance in total mercury concentration in rock bass and 80.5% in hog suckers was accounted for by mercury in water, sediment, and benthic invertebrates. Independent variables accounted for 97.4% of the variance in total mercury concentration in benthic invertebrates. The potential implication of these results for environmental monitoring programs is discussed.
Fractionation of Inorganic Phosphates in Calcareous Sediments
Authors: Hieltjes Arnold H. M. , Lijklema Lambertus 
Published: July 2010

AbstractThe selectivity of current fractionation schemes for inorganic phosphates in sediments has been tested on pure compounds. Results indicate that effective removal of calcium carbonate through ammonium chloride extraction is necessary in order to achieve satisfactory discrimination between iron‐ or aluminum‐bound phosphates and calcium phosphates. A simple extraction procedure based on this information has been applied to the sediments of Lake Brielle.
Methane Production From Ozonated Pulp Mill Effluent
Authors: Bremmon Craig E. , Jurgensen Martin F. , Patton John T. 
Published: July 2010

AbstractA study was made on the production of methane from desugared spent sulfite liquor (SSL) reacted with ozone. The ozonated SSL was fed continuously to three anaerobic fermenters for three months as the sole source of carbon and energy. The fermenters were inoculated with anaerobic bacteria obtained from sewage sludge and acclimated for 1 month in ozonated SSL prior to continuous fermentation. Chemical and biological parameters such as COD, BOD5, total sulfur content, redox potential, pH, fatty acid composition, and methane bacteria populations were monitored to determine changes in the SSL during fermentation.Methane production from ozone‐treated SSL averaged 1.7 liters/liter or 17 ml of CH4 produced/gram of volatile solids fed. Fatty acids analysis of fermenter effluent indicated a net production of 58 mM/liter of acetate during ozonated SSL fermentation. This acetic acid production shows future potential for further fermentation by protein‐producing yeast. Although the rate of conversion of volatile solids to CH4 in this process was not competitive with domestic or agricultural waste digesters, this study did indicate the potential benefits of ozonating organic wastes for increased methane fermentation yields.
A Mathematical Model for Estimating Pesticide Losses in Runoff
Authors: Haith D. A. 
Published: July 2010

AbstractA simple mathematical model has been proposed for the estimation of losses of dissolved and solid‐phase pesticide in cropland runoff. The model is designed for use in water quality and pesticide screening studies for which field pesticide runoff data are unavailable. Hence, the model is based on commonly used methods for runoff and soil loss predictions and does not require calibration. A comparison of model predictions with measured atrazine (2‐chloro‐4 (ethylamino)‐6‐(isopropylamino)‐s‐triazine) losses from two small Georgia watersheds has indicated that the model provides a reasonable means of estimating the approximate magnitudes of long‐term (3‐years for the two watersheds) total pesticide runoff losses. Although large errors were sometimes observed in estimates of losses from single runoff events, the observed variations in pesticide losses among events and the distribution of these losses into dissolved and solid‐phase components were reflected in model predictions.
Nitrate‐Nitrogen Leached Below the Root Zone During and Following Alfalfa
Authors: Robbins C. W. , Carter D. L. 
Published: July 2010

AbstractThe nitrate‐nitrogen (NO3‐N) contribution to subsurface drainage water by irrigated alfalfa (Medicago sativa L.) in crop rotations was evaluated by measuring the soil water flux and NO3‐N concentration below the root zone of alfalfa and crops following alfalfa with and without additional nitrogen fertilization. Under alfalfa grown on Portneuf silt loam (Durixerollic Calciorthid) with a permeable hardpan, 44 kg NO3‐N ha−1 year−1 moved below the root zone at concentrations between 3 and 15 ppm. During the growing season following alfalfa, 85–96 kg NO3‐N ha−1 year−1 moved below the root zone under nonfertilized bean (Phaseolus vulgaris) crops at concentrations between 1 and 83 ppm. The second growing season after alfalfa, 17–29 kg NO3‐N ha−1 year−1 at 3–15 ppm NO3‐N moved below the root zone of nonfertilized bean and wheat (Triticum aestivum L.) crops. A field planted to corn (Zea mays L.) and fertilized with 200 and 170 kg N ha−1 the first and second year after alfalfa lost 153 and 108 kg NO3‐N ha−1, respectively, from leaching. Leachate N concentrations varied from 1 to 64 ppm. Unfertilized corn lost 60 and 17 kg NO3‐N/ha the first and second year after alfalfa, respectively, at leachate concentrations of 1–31 ppm. The NO3‐N concentration in the soil solution below only slightly permeable hardpan areas was between 13 and 67 ppm, but only 10–23 kg ha−1 year−1 moved below the root zone because of the lower water flux through the hardpan. Comparing these results with previous data for the same area suggests that considerable denitrification and/or dilution takes place at the water table interface since 5.2 ppm NO3‐N was the highest concentration measured in the subsurface drainage water with an average of 3.2 ppm NO3‐N. The NO3‐N contributed by alfalfa in the crop rotation was estimated to equal just half of that accounted for in the subsurface drainage in a previous study on the same irrigated tract.
Areal, Vertical, and Temporal Differences in Ground Water Chemistry: I. Inorganic Constituents
Authors: Spalding Roy F. , Exner Mary E. 
Published: July 2010

AbstractDefinite areal, vertical, and temporal differences were observed in the ground water chemistry of a 62 km2 area in Nebraska's Platte Valley. A network of 53 wells was monitored 10 times between July 1975 and July 1976 for dissolved solids, Ca2+, Mg2+, Na+, K+, HCO3−, SO42−, Cl−, F−, NO3‐N, PO4‐P, SiO2, pH, and temperature.Areal differences were most pronounced in the shallow ground water and reflected upgradient land use and soil type. Average total dissolved solids (TDS) and nitrate‐nitrogen (NO3‐N) concentrations ranged from 557 to 2,210 mg/liter and from 0.1 to 33 mg/liter, respectively, with the lowest concentrations occurring downgradient from near‐pristine areas and the highest concentrations occurring downgradient from cultivated and irrigated fields.In ground water downgradient from cultivated and irrigated fields, most of the chemical parameters had pronounced decreases in concentration with depth. Stratification was more pronounced in the bottomland than in the terrace and in the latter reflects mixing of the ground water caused by intensive pumping of irrigation water during the last four decades. Magnesium and potassium had marked decreases with depth regardless of upgradient land use.Marked cyclic fluctuations in NO3‐N and SO42− concentrations generally were observed in the bottomland ground water. Sulfate concentrations, which were significantly correlated with TDS, Ca2+, Mg2+ Na+, and Cl− (r ≥ +0.89), peaked in late winter and early spring.Ground water in secondary aquifers confined within or beneath a layer of clayey silt had an average TDS concentration of 304 mg/liter and almost negligible amounts (≤ 0.1 mg/liter) of NO3‐N. Temporal fluctuations in chemical constituents from these aquifers were the smallest observed within the study area.
The Influence of Organic Wastes and Inorganic Nitrogen Sources on Soil Nitrogen, Yield, and Elemental Composition of Corn
Authors: Sims J. T. , Boswell F. C. 
Published: July 2010

AbstractThis experiment evaluated the effect of synthetic N fertilizers, organic wastes, and fortified organic wastes on soil mineral and total N, crop yield, and elemental composition. Treatments consisted of equivalent rates of N (224 kg/ha) as NH4NO3, urea, sewage sludge, sewage sludge fortified with urea, leather tankage (LT), and organiform (leather tankage chemically fortified with urea‐formaldehyde). Corn (Zea mays L., cv. ‘DeKalb XL‐394’) was used as an indicator crop and soil N measurements were conducted throughout the growing season.Soil levels of NH4‐N, NO4‐N, and total N indicated that the organic waste materials provided adequate amounts of available N for crop growth. Fortified and nonfortified wastes resulted in similar amounts of mineral and total N in the soil, indicating that fortification could reduce application problems associated with high loading rates of organic wastes. Accumulations of mineral N at the end of the corngrowing season suggest that the loading rates used in this study may have been excessive. While this excess available N would be beneficial for subsequent crops, it could also provide a source of contamination for surface and ground waters.Organic wastes consistently produced yields and plant tissue N levels equal to or greater than yields and N levels obtained with ammonium nitrate or urea. The treatments increased Zn in plant tissue and on plots receiving sewage sludge, and Mn and Cr accumulations in the tissue of plants grown on leather tankage treated plots. Except for the LT‐treated plots at the early growth stage, crop growth and yield were uninhibited.
The Enrichment of Soil Phosphorus in Runoff Sediments
Authors: Sharpley A. N. 
Published: July 2010

AbstractThe effect of varying soil physical and chemical properties, soil slope, rainfall intensity, and source on the enrichment of soil P in runoff was evaluated under simulated rainfall conditions. The enrichment of P in runoff increased with increased P additions. The P enrichment ratio (ER) of Bernow soil increased from 2.43 to 6.29 at P additions of 0 and 100 kg P/ha, respectively. As rainfall intensity and soil slope were increased, ER decreased correspondingly. A significant linear relationship between in (ER) and in (sediment discharge) was obtained for all treatments studied. Similar slopes were obtained for soils ranging in texture from a fine sandy loam (−0.233, Bernow soil) to a clay (−0.264 and −0.252 for Houston and Pullman soils, respectively) under similar experimental conditions. In addition, the slopes were not affected by soil P status as slopes of −0.233 and −0.276 at 0 and 100 kg P/ha additions, respectively, were obtained for Bernow soil. With an increase in energy of runoff and kinetic energy of rainfall, a significant increase in slope of the relationship between In (ER) and in (sediment discharge) was obtained. In contrast, a decrease in energy of rain as in the case of overland flow and increased soil cover, resulted in a significant decrease in slope. The data indicated that runoff and rainfall energy and soil P status have a greater effect on ER than soil physical properties. A general relationship between ER and sediment discharge covering all treatments studied predicted ER values very similar to those measured in field studies and those predicted by a general relationship derived from field studies.
Die‐off of Fecal Indicator Organisms Following Land Application of Poultry Manure
Authors: Crane S. R. , Westerman P. W. , Overcash M. R. 
Published: July 2010

AbstractLand‐applied animal manure can be a major contributor of agricultural nonpoint source pollution. For surface‐applied manures the time period prior to the first runoff is of greatest concern, because most enteric species initially exhibit rapid die‐off rates. The objectives of this investigation were to follow the die‐off of indicator organisms after manure application to a bar? soil surface and to ascertain if die‐off could be accurately modeled by first‐order‐kinetics. Poultry manure was surface‐applied at approximately 36.5 and 164 metric tons/ha on Davidson clay loam and Norfolk sandy loam plots in a controlled environment chamber at a constant temperature (24.5°C). Soil samples were analyzed at intervals during a 30‐day period for fecal coliforms and fecal streptococci. Modeling die‐off of fecal coliform during the first 7 days gave good agreement with experimental data showing an average die‐off rate constant of 0.29/day. After 7 days, regrowth of fecal coliform populations was seen on all plots. Fecal streptococcal numbers declined steadily after the first 3 days of the 30‐day study and exhibited an average first‐order rate constant of 0.093/day. Neither soil type nor manure application rate seemed to influence the decline in organism populations. First‐order kinetics did not explain all aspects of die‐off, but it appears this model could be successfully employed as a first approximation for estimating bacterial kinetics in a larger nonpoint source pollution model for agricultural lands.
Effects of Drilling Fluids on Soils and Plants: I. Individual Fluid Components
Authors: Miller Raymond W. , Honarvar Shahnaz , Hunsaker Barbara 
Published: July 2010

AbstractThe effects of 31 drilling fluid (drilling mud) components on the growth of green beans (Phaseolus vulgaris L., ‘Tendergreen’) and sweet corn [Zea may var. saccharata (Sturtev.) ‘Bailey,’ Northrup King 199] were evaluated in greenhouse studies. Plants grew well in fertile Dagor silt loam soil (Cumulic Haploxeroli) when the soil was mixed with most soil‐component mixtures at disposal proportions normally expected. Vinyl acetate and maleic acid polymer (VAMA) addition caused significantly increased growth at the 95% confidence level. No statistically significant depression of plant growth occurred at normal rates with asbestos, asphalt, barite, bentonite, calcium lignosulfonate, sodium polyacrylate, a modified tannin, ethoxylated nonylphenol, a filming amine, gilsonite, a Xanthan gum, paraformaldehyde, a pipe dope, hydrolized polyacrylamide, sodium acid pyrophosphate, sodium carboxymethyl cellulose, sodium hydroxide added as pellets, and a sulfonated tall oil.Statistically significant reductions in plant yields (at the 95% confidence level) occurred at normal disposal rates with a long‐chained aliphatic alcohol, sodium dichromate, diesel oil, guar gum, an iron chromelignosulfonate, lignite, a modified asphalt, a plant fibersynthetic fiber mixture, lignite, a nonfermenting starch, potassium chloride, pregelatinized starch, and sulfated triglyceride.Thirteen drilling fluid components added individually to a fluid base (water, bentonite, and barite) and then to soil, were also tested for their effect on plant growth. Only the sulfated triglyceride (Torq‐Trim®) and the long‐chain (high molecular weight) alcohol (Drillaid 405®) caused no plant growth reductions at either rate added. The modified tannin (Desco®) caused minimal reduction in bean growth only when added to soil in “excess” levels. The pregelatinized starch, sodium dichromate, nonfermenting starch (Dextrid®), plant and synthetic fiber mix (Kwik‐Seal®), iron chromelignosulfonate (Q‐Broxin®), and guar gum (Gendril Thik®) did not depress plant growth at normal disposal rates used, but they did depress plant growth with the abnormally high (excess) rates of addition to soil. No plants grew either normal or excessive addition rates when potassium chloride was used. Also, no plants grew when abnormally high rates of sodium dichromate, lignite + sodium hydroxide, or calcium lignosulfonate + sodium hydroxide were added.
Movement of Chloride in a Soil with Variable Charge Properties: I. Chloride Systems
Authors: Chan K. Y. , Geering H. R. , Davey B. G. 
Published: July 2010

AbstractThe movement of synthetic chloride solutions, simulating a treated sanitary landfill leachate, through columns filled with the subsoil of a xanthic ferralsol were studied in the laboratory. The chloride movement did not follow the miscible displacement equation or more sophisticated models, because the amount of positive charge carried by the soil depended on both pH and the ionic strength of the solution moving through it. During movement of the alkaline synthetic leachate into the column, the amount of positive charge increased due to the higher ionic strength of the leachate relative to the soil solution. A further temporary increase in positive charge also took place due to the decrease in pH induced by cation exchange caused by the leachate front. Later, the desorption of Cl took place as the alkaline leachate titrated the soil to pH > 9.0 and the positive charge was neutralized by OH adsorption. These results show that variation in the positive charge of the soil, induced by the solution moving through it, causes the Cl outflow curve to deviate from theory. Before more advanced theories of miscible displacement can be applied to this type of situation, it will be necessary to develop adequate kinetic theories to describe the changes in the soil's charge properties induced by the solution moving through it.
Effect of Nitrification on Movement of Trace Metals in Soil Columns
Authors: Chang Fu‐Hsian , Broadbent F. E. 
Published: July 2010

AbstractSoil column experiments were conducted with sludge‐treated and untreated samples of two soils, Omni silty clay and Delhi loamy sand, to determine whether protons generate during the nitrification process would affect the mobility of the trace metals Cd, Cr, Cu, Mn, Ph, and Zn. Columns 5 cm × 100 cm were leached bi‐ or tri‐weekly with 7.5‐cm applications of solutions of CaCl2, NH4Cl, or KCl. Trace metals in effluents from the columns were analyzed after each application of leaching solution. After 11 applications over a period of several months the columns were sectioned and the vertical distribution of 2N HCl‐extractable metals determined.Average concentrations of metals in column effluents were well below 1 ppm in all cases except Zn eluted from untreated Delhi loamy sand where 20 mM NH4Cl or KCl leaching solutions produced effluent concentrations slightly above 1 ppm. There was evidence of nitrification affecting movement of several of the metals, particularly in the cases of Mn, Zn, Cu, and Cd in the untreated Delhi soil. The presence of sludge had a pronounced stabilizing influence of Cd and Zn, and to a lesser degree on other metals, probably as a result of organo‐metal complexes.Much of the input labeled NH4‐N was denitrified, as shown by recoveries of N ranging from 14 to 20% in the Omni soil and 40 to 78% in the Delhi soil. Proton generation during nitrification was, thus, partially offset by neutralization during denitrification. It was concluded that nitrification had relatively little effect on metal mobility under the conditions of the experiment.
A Comparison of the Distribution of Industrially Released 238Pu and Fallout 239,240Pu in Temperate, Northern United States Soils
Authors: Alberts James J. , Bobula Charles M. , Farrar David T. 
Published: July 2010

AbstractStudies of 238Pu dispersed from the stack of a nuclear fabrication facility in southwestern Ohio indicate that the predominant deposition occurs within 8 km of the site. Plutonium‐238 from this source exhibits the same relative solubility as 239,240Pu from fallout. Both 238Pu from the facility and 239,240Pu from fallout move downward through the soil column, but 238Pu appears to have moved more slowly. Reasons for this apparent differential behavior are explored.
Extraction, Speciation, and Analysis of Arsenic and Arsenical Herbicides in Runoff: Evaluation of Simple Methods at the ppb Level
Authors: Wauchope R. D. , Yamamoto M. 
Published: July 2010

AbstractThe use of a column chromatographic technique for separation of inorganic arsenic (As) from methyl‐ and dimethyl‐derivatives, and flameless atomic absorption technique for quantitating the separated As species at the ppb level, have been evaluated for use in studies of the behavior of arsenate and methanearsonate (CH3AsO32‐) ions in runoff (water and suspended sediment). The former ion is a natural component of soils. The latter ion is extensively used as an herbicide in the sodium and disodium salt forms, commonly called MSMA and DSMA, respectively. Runoff from two watersheds was spiked with 200 ppb As as arsenate or 189 ppb As as methanearsonate, or both. The partitioning of the As between sediment and water phases was measured and the As species in both phases were identified and quantitated. Recoveries ranged from 80 to 100%, and relative precision between samples averaged 10% for As concentrations between 10 and 200 ppb. In the partitioning of the added As between sediment and water phases of the runoff, arsenate appears to be much more strongly adsorbed by sediments than in methanearsonate. Although both speciation and quantitation techniques are relatively simple, they will be adequate for exploratory studies on arsenate and methanearsonate behavior in runoff and impoundments.