bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retention Equations of Nonionic Organic Chemicals in Soil Column Chromatography with Methanol–Water Eluents
Authors: Xu Feng , Liang Xinmiao , Lin Bingcheng 
Published: June 2010

ABSTRACTResearch efforts dealing with chemical transportation in soils are needed to prevent damage to ground water. Methanol‐containing solvents can increase the translocation of nonionic organic chemicals (NOCs). In this study, a general log‐linear retention equation, log k′ = log k′w − Sφ (Eq. [1]), was developed to describe the mobilities of NOCs in soil column chromatography (SCC). The term φ denotes the volume fraction of methanol in eluent, k′ is the capacity factor of a solute at a certain φ value, and log k′w and −S are the intercept and slope of the log k′ vs. φ plot. Two reference soils (GSE 17204 and GSE 17205) were used as packing materials, and were eluted by isocratic methanol–water mixtures. A model of linear solvation energy relationships (LSER) was applied to analyze the k′ from molecular interactions. The most important factor determining the transportation was found to be the solute hydrophobic partition in soils, and the second‐most important factor was the solute hydrogen‐bond basicity (hydrogen‐bond accepting ability), while the less important factor was the solute dipolarity–polarizability. The solute hydrogen‐bond acidity (hydrogen‐bond donating ability) was statistically unimportant and deletable. From the LSER model, one could also obtain Eq. [1] The experimental k′ data of 121 NOCs can be accurately explained by Eq. [1] The equation is promising to estimate the solute mobility in pure water by extrapolating from lower‐capacity factors obtained in methanol–water mixed eluents.
Effect of Mineral and Manure Phosphorus Sources on Runoff Phosphorus
Authors: Kleinman Peter J. A. , Sharpley Andrew N. , Moyer Barton G. , Elwinger Gerald F. 
Published: June 2010

ABSTRACTConcern over nonpoint‐source phosphorus (P) losses from agricultural lands to surface waters has resulted in scrutiny of factors affecting P loss potential. A rainfall simulation study was conducted to quantify the effects of alternative P sources (dairy manure, poultry manure, swine slurry, and diammonium phosphate), application methods, and initial soil P concentrations on runoff P losses from three acidic soils (Buchanan–Hartleton, Hagerstown, and Lewbeach). Low P (12 to 26 mg kg−1 Mehlich‐3 P) and high P (396 to 415 mg kg−1 Mehlich‐3 P) members of each soil were amended with 100 kg total P ha−1 from each of the four P sources either by surface application or mixing, and subjected to simulated rainfall (70 mm h−1 to produce 30 min runoff). Phosphorus losses from fertilizer and manure applied to the soil surface differed significantly by source, with dissolved reactive phosphorus (DRP) accounting for 64% of total phosphorus (TP) (versus 9% for the unamended soils). For manure amended soils, these losses were linearly related to water‐soluble P concentration of manure (r2 = 0.86 for DRP, r2 = 0.78 for TP). Mixing the P sources into the soil significantly decreased P losses relative to surface P application, such that DRP losses from amended, mixed soils were not significantly different from the unamended soil. Results of this study can be applied to site assessment indices to quantify the potential for P loss from recently manured soils.
Volatilization and Degradation of Soil‐Applied Dimethylselenide
Authors: Dungan Robert S. , Yates Scott R. , Frankenberger William T. 
Published: June 2010

ABSTRACTDimethylselenide (DMSe) is a highly volatile gas that is produced by indigenous microorganisms in seleniferous soils and sediments; however, little is known about the soil conditions that affect the persistence of DMSe and its transport to the atmosphere. In this study we investigated the effect of moisture content, temperature, and organic amendments on the degradation of soil‐applied DMSe. The degradation of DMSe was entirely a result of biological mechanisms, but changes in temperature (20–40°C) and soil moisture content (30–70% of the maximum water holding capacity) had little influence on the degradation rate. In contrast, amending soil with either 1% casein or gluten (by weight) had an inhibitory effect on the degradation of DMSe. After 18 d, 2.1 times more DMSe was present in the casein‐amended soil and 2.6 times more DMSe was present in the gluten‐amended soil. The transport of DMSe in packed soil columns was also investigated. Increasing the depth to soil surface was found to significantly decrease the amount of DMSe transported to the air. After 6 d, 57% of DMSe injected 10 cm below the soil surface was volatilized. At an injection depth of 20 cm the cumulative emissions were reduced by 38% and at 30 cm the cumulative emissions were reduced by 51%. In columns containing 1% casein or gluten in the top 5 cm of soil the cumulative loss of DMSe was about 9% higher than in unamended soil. Increasing our understanding of the soil conditions that influence the gaseous diffusion of DMSe should help in determining the feasibility of using Se volatilization as a remediation technique.
Phosphorus Characteristics of Dairy Feces Affected by Diets
Authors: Dou Zhengxia , Knowlton Katharine F. , Kohn Richard A. , Wu Zhiguo , Satter Larry D. , Zhang Gangya , Toth John D. , Ferguson James D. 
Published: June 2010

ABSTRACTPhosphorus (P) surplus on dairy farms, especially confined operations, contributes to P buildup in soils with increased potential for P loss to waters. One approach to reduce P surplus and improve water quality is to optimize P feeding and improve P balance on farms. Here we report how varying P concentrations in lactating cow diets affects the amount as well as the chemical forms and fraction distribution of P in fecal excretion, and the environmental implications of this effect. Analysis of fecal samples collected from three independent feeding trials indicates that increasing dietary P levels through the use of P minerals not only led to a higher concentration of acid digest total phosphorus (TP) in feces, but more importantly increased the amount and proportion of P that is water soluble and thus most susceptible to loss in the environment. For instance, with diets containing 3.4, 5.1, or 6.7 g P kg−1 feed dry matter (DM), the water‐soluble fraction of fecal P was 2.91, 7.13, and 10.46 g kg−1 fecal DM, respectively, accounting for 56, 77, and 83% of acid digest TP. The other fecal P fractions (those soluble in dilute alkaline and acid extractants) remained small and were unaffected by dietary P concentration. Excess P in the P supplemented diets was excreted in feces as water‐soluble forms. A simple measure of inorganic phosphorus (Pi) in a single water extract is highly responsive to changes in diet P concentrations and hence can be indicative of dietary P status. A fecal P indicator concept is proposed and discussed.
On‐Farm Evaluation of Aluminum Sulfate (Alum) as a Poultry Litter Amendment
Authors: Sims J. T. , Luka‐McCafferty N. J. 
Published: June 2010

ABSTRACTAluminum sulfate [alum; Al2(SO4)3] amendment of poultry litters has been suggested as a best management practice to help reduce the potential environmental effects of poultry production. Past research has shown that alum treatment reduced NH3 emissions from litters, decreased the loss in runoff of P and trace metals from litter‐amended soils, improved poultry health, and reduced the costs of poultry production. We conducted a large scale, “on‐farm” evaluation of alum as a poultry (broiler) litter amendment on the Delmarva peninsula to determine the effect of alum on (i) litter properties and elemental composition and (ii) the solubility of several elements in litter that are of particular concern for water quality (Al, As, Cu, P, and Zn). Alum was applied over a 16‐mo period to 97 poultry houses on working poultry farms; 97 houses on other farms served as controls (no alum). Litter samples were analyzed initially and after approximately seven alum applications. We found that alum decreased litter pH and the water solubility of P, As, Cu, and Zn. Alum‐treated houses also had higher litter total N, NH4–N, and total S concentrations and thus a greater overall fertilizer value than litters from the control houses. Higher litter NH4–N values also suggest that alum reduced NH3 losses from litters. Thus, alum appears to have promise as a best management practice (BMP) for poultry production. Future research should focus on the long‐term transformations of P, Al, As, Cu, and Zn in soils amended with alum‐treated litters.
Increasing Bioavailability of Phosphorus from Fly Ash through Vermicomposting
Authors: Bhattacharya S. S. , Chattopadhyay G. N. 
Published: June 2010

ABSTRACTDue to the environmental problems created by large‐scale fly ash generation throughout the world, efforts are being made to recycle these materials. An important component of the recycling effort is using fly ash to improve low‐fertility soils. Because availability of many nutrients is very low in fly ash, available ranges of such nutrients must be improved to increase the effectiveness of fly ash as a soil amendment. In the present study, we assessed the possibility of increasing P bioavailability in fly ash through vermicomposting in a yard experiment. Fly ash was mixed with organic matter in the form of cow (Bos taurus) dung at 1:3, 1:1, and 3:1 ratios and incubated with and without epigeic earthworm (Eisenia fetida) for 50 d. The concentration of phosphate‐solubilizing bacteria (PSB) was found to increase many fold in the earthworm‐treated series of fly ash and organic matter combinations compared with the series without earthworm. This helped to transform considerable amounts of insoluble P from fly ash into more soluble forms and thus resulted in increased bioavailability of the nutrients in the vermicomposted series. Among different combinations of fly ash and organic matter, P availability in fly ash due to vermicomposting was significantly higher in the 1:1 fly ash to cow dung treatment compared with the other treatments.
Testing Soils and Cornstalks to Evaluate Nitrogen Management on the Watershed Scale
Authors: Balkcom Kipling S. , Blackmer Alfred M. , Hansen David J. , Morris Thomas F. , Mallarino Antonio P. 
Published: June 2010

ABSTRACTHigh nitrate (NO3–N) concentrations in Iowa rivers have been linked to areas of intensive row crop production, but they have not been experimentally linked to specific management practices used during row crop production. This study demonstrates how the late‐spring test for soil NO3–N and the end‐of‐season test for cornstalk NO3–N can be used to measure N sufficiency levels across many fields and how the results can be used to evaluate management practices within a watershed. More than 3200 soil and cornstalk samples were collected over a 12‐yr period from fields planted to corn (Zea maysL.) and already fertilized by farmers using their normal practices. Results showed that early‐season rainfall and associated N losses were major factors affecting N concentrations in soils and cornstalks. Evidence for NO3–N movement from fields to rivers was provided by an inverse relationship between annual means for NO3–N concentrations in soils and rivers. Because these losses can be avoided by delaying N applications, the practice of applying N several weeks or months before plants grow was linked to inefficient use of fertilizer and manure N by crops. Results of the study demonstrate how aggregate analyses of soil and cornstalk samples collected across many farms and years make it possible to identify the major factors affecting N management outcomes and, therefore, N management practices that are likely to produce the best outcomes within a watershed or region. This approach seems to have unique potential to interrelate the management practices of farmers, the efficiency of N fertilization, and NO3–N concentrations in rivers.
Herbicides and Herbicide Degradation Products in Upper Midwest Agricultural Streams during August Base‐Flow Conditions
Authors: Kalkhoff Stephen J. , Lee Kathy E. , Porter Stephen D. , Terrio Paul J. , Thurman E. Michael 
Published: June 2010

ABSTRACTHerbicide concentrations in streams of the U.S. Midwest have been shown to decrease through the growing season due to a variety of chemical and physical factors. The occurrence of herbicide degradation products at the end of the growing season is not well known. This study was conducted to document the occurrence of commonly used herbicides and their degradation products in Illinois, Iowa, and Minnesota streams during base‐flow conditions in August 1997. Atrazine, the most frequently detected herbicide (94%), was present at relatively low concentrations (median 0.17 μg L−1). Metolachlor was detected in 59% and cyanazine in 37% of the samples. Seven of nine compounds detected in more than 50% of the samples were degradation products. The total concentration of the degradation products (median of 4.4 μg L−1) was significantly greater than the total concentration of parent compounds (median of 0.26 μg L−1). Atrazine compounds were present less frequently and in significantly smaller concentrations in streams draining watersheds with soils developed on less permeable tills than in watersheds with soils developed on more permeable loess. The detection and concentration of triazine compounds was negatively correlated with antecedent rainfall (April–July). In contrast, acetanalide compounds were positively correlated with antecedant rainfall in late spring and early summer that may transport the acetanalide degradates into ground water and subsequently into nearby streams. The distribution of atrazine degradation products suggests regional differences in atrazine degradation processes.
Macroinvertebrate Biomonitoring in Intermittent Coastal Plain Streams Impacted by Animal Agriculture
Authors: Davis Stephanie , Golladay Stephen W. , Vellidis George , Pringle Catherine M. 
Published: June 2010

ABSTRACTLittle attention has been given to the ecology of intermittent coastal plain streams in the southeastern United States, and it is not known whether available macroinvertebrate biomonitoring methods reliably detect degradation in these streams. This study compared differences in biomonitoring metrics between reference and agricultural streams, and between the flow period (January–April) and the intermittent flow period (May–December). Percentages of crustaceans, isopods, and Ephemeroptera–Plecoptera–Trichoptera (EPT) were significantly higher at the reference site than the two most impacted sites during the flow period, probably resulting from the abundance of leaf litter and lower temperatures. During this same period, the agriculturally impacted sites had a significantly higher percentage of dipterans—a group that thrives in the silty, nutrient‐rich waters. Four metrics (percent Crustacea, Isopoda, Diptera, and EPT) had no overlap between values for the most impacted and the least impacted sites during the flow period, but no metrics were able to detect more discrete differences among sites. Sites were physically and biologically similar during the intermittent period when natural stresses (i.e., stagnant water, high temperatures, low dissolved oxygen) were high, with many metrics, such as percentages of dominant family, burrowers, chironomids, and dipterans becoming similar at all sites. Our findings indicate that development of a better understanding of invertebrate fauna in reference conditions and of the natural variation in intermittent streams is necessary to develop effective biomonitoring programs for these systems.
Phosphorus Sorption and Availability in Soils Amended with Animal Manures and Sewage Sludge
Authors: Siddique Muhammad Tariq , Robinson J. Stephen 
Published: June 2010

ABSTRACTSoils that receive large applications of animal wastes and sewage sludge are vulnerable to releasing environmentally significant concentrations of dissolved P available to subsurface flow owing to the gradual saturation of the soil's P sorption capacity. This study evaluated P sorption (calculated from Langmuir isotherms) and availability of P (as CaCl2–P and resin P) in soils incubated for 20 d with poultry litter, poultry manure, cattle slurry, municipal sewage sludge, or KH2PO4, added on a P‐equivalent basis (100 mg P kg−1). All the P sources had a marked negative effect on P sorption and a positive effect on P availability in all soils. In the cattle slurry– and KH2PO4–treated soils, the decreases in P sorption maximum (19–66%) and binding energy (25–89%) were consistently larger than the corresponding decreases (7–41% and 11–30%) in poultry litter–, poultry manure–, and sewage sludge–treated soils. The effects of cattle slurry and KH2PO4on P availability were, in most cases, larger than those of the other P sources. In the poultry litter, poultry manure, and sewage sludge treatments, the increase in soil solution P was inversely related (R2= 0.75) to the input of Ca from these relatively high Ca (13.5–42 g kg−1) sources. Correlation analyses implied that the magnitude of the changes in P sorption and availability was not related to the water‐extractable P content of the P sources. Future research on the sustainable application of organic wastes to agricultural soils needs to consider the non‐P‐ as well as P‐containing components of the waste.
Sediment Retention in Rangeland Riparian Buffers
Authors: Hook Paul B. 
Published: June 2010

ABSTRACTControlling nonpoint‐source sediment pollution is a common goal of riparian management, but there is little quantitative information about factors affecting performance of rangeland riparian buffers. This study evaluated the influence of vegetation characteristics, buffer width, slope, and stubble height on sediment retention in a Montana foothills meadow. Three vegetation types (sedge wetland, rush transition, bunchgrass upland) were compared using twenty‐six 6‐ × 2‐m plots spanning 2 to 20% slopes. Plots were clipped moderately (10–15 cm stubble) or severely (2–5 cm stubble). Sediment (silt + fine sand) was added to simulated overland runoff 6, 2, or 1 m above the bottom of each plot. Runoff was sampled at 15‐s to >5‐min intervals until sediment concentrations approached background levels. Sediment retention was affected strongly by buffer width and moderately by vegetation type and slope, but was not affected by stubble height. Mean sediment retention ranged from 63 to >99% for different combinations of buffer width and vegetation type, with 94 to 99% retention in 6‐m‐wide buffers regardless of vegetation type or slope. Results suggest that rangeland riparian buffers should be at least 6 m wide, with dense vegetation, to be effective and reliable. Narrower widths, steep slopes, and sparse vegetation increase risk of sediment delivery to streams. Vegetation characteristics such as biomass, cover, or density are more appropriate than stubble height for judging capacity to remove sediment from overland runoff, though stubble height may indirectly indicate livestock impacts that can affect buffer performance.
Estimating Turf Pesticide Volatilization from Simple Evapotranspiration Models
Authors: Walden Rebecca R. , Haith Douglas A. 
Published: June 2010

ABSTRACTA previously developed model by Haith et al. (2002) related pesticide volatilization from turf to evapotranspiration (ET) by scaling factors determined from vapor pressures and heats of vaporization. Although the model provided volatilization estimates that compared well with field measurements, it relied on the Penman ET equation, requiring hourly temperature, wind speed, and solar radiation data, none of which are routinely available at field sites. The current study determined that the volatilization model works equally well with a simpler ET equation requiring only daily temperatures. Three daily temperature‐based ET models were evaluated as vehicles for estimating pesticide volatilization from turf: Hamon, Hargreaves–Samani, and a modified Priestley–Taylor. When compared with field volatilization measurements for eight pesticides, volatilization estimates produced from the Hargreaves–Samani model most closely approximated both the field observations and the previous estimates based on the more data‐intensive Penman model. Mean estimated volatilization exceeded mean observations by 15% and the coefficient of variation (R2) between estimates and observations was 0.65. The comparable values based on Penman ET were 17% and 0.63, respectively.
Gaseous Nitrogen Emissions and Mineral Nitrogen Transformations as Affected by Reclaimed Effluent Application
Authors: Master Y. , Laughlin R. J. , Shavit U. , Stevens R. J. , Shaviv A. 
Published: June 2010

ABSTRACTIrrigation with reclaimed effluent (RE) is essential in arid and semiarid regions. Reclaimed effluent has the potential to stimulate gaseous N losses and affect other soil N processes. No direct measurements of the N2 and N2O emissions from Mediterranean soils have been conducted so far. We used the 15N gas flux method in a field and a laboratory experiment to study the effect of RE irrigation on gaseous N losses and other N transformations in a Grumosol (Chromoxerert) soil. The fluxes of N2, N2O, and NH3 were measured from six Grumosol lysimeters following application of either fresh water or RE. The N fertilizer was applied either as 15NH4 or 15NO3 Only up to 0.3% from the applied N fertilizer was lost as N2O + NH3 Reclaimed effluent enhanced the losses of NH3, but did not affect those of N2O. Nitrification and denitrification were equally important to N2O production. Laboratory incubations were performed to both confirm the influence of the irrigation water type and to test the effect of moisture content. Significant quantities of N2 and N2O (up to 3.1% of the applied fertilizer) were emitted from saturated soils. Reclaimed effluent application did not induce higher N2O emissions, yet significantly more (approximately 33%) N2 was emitted from RE‐irrigated soils. Denitrification contributed up to 75% of the N2O amounts emitted from saturated soils. Reclaimed effluent application inhibited nitrification in the Grumosol by 15 to 25% and induced NO2 accumulation in soils incubated at a field‐capacity moisture content.
pH, Dissolved Oxygen, and Adsorption Effects on Metal Removal in Anaerobic Bioreactors
Authors: Willow Mark A. , Cohen Ronald R. H. 
Published: June 2010

ABSTRACTAnaerobic bioreactors were used to test the effect of the pH of influent on the removal efficiency of heavy metals from acid‐rock drainage. Two studies used a near‐neutral‐pH, metal‐laden influent to examine the heavy metal removal efficiency and hydraulic residence time requirements of the reactors. Another study used the more typical low‐pH mine drainage influent. Experiments also were done to (i) test the effects of oxygen content of feed water on metal removal and (ii) the adsorptive capacity of the reactor organic substrate. Analysis of the results indicates that bacterial sulfate reduction may be a zero‐order kinetic reaction relative to sulfate concentrations used in the experiments, and may be the factor that controls the metal mass removal efficiency in the anaerobic treatment systems. The sorptive capacities of the organic substrate used in the experiments had not been exhausted during the experiments as indicated by the loading rates of removal of metals exceeding the mass production rates of sulfide. Microbial sulfate reduction was less in the reactors receiving low‐pH influent during experiments with short residence times. Sulfate‐reducing bacteria may have been inhibited by high flows of low‐pH water. Dissolved oxygen content of the feed waters had little effect on sulfate reduction and metal removal capacity.