bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating Nitrate Leaching with a Transfer Function Model Incorporating Net Mineralization and Uptake of Nitrogen
Authors: Ren Li , Ma Junhua , Zhang Renduo 
Published: June 2010

ABSTRACTBecause of the complex interaction of chemical and biological processes of nitrogen (N) in soils, it is difficult to estimate the leaching of nitrate with various N transformations in porous media. In this study, a transfer function model was developed to simulate the outflow concentration of nitrate in soils during the growth of winter wheat (Triticum aestivum L.), taking into account the main N transformations using source and sink terms. The source and sink terms were treated as inputs to the solute transport volume and incorporated into the transfer function model to characterize their effects on nitrate concentration in the outflow. A field experiment was conducted in three nonweighing lysimeters for 181 d. Nitrate concentrations were measured along the 2‐m soil profile of each lysimeter at different times. Comparison between the experimental data and simulated results with the transfer function showed that the model provided reasonable prediction of the nitrate leaching process as well as the total amount leached. Results also indicated that considering the N transformations in the transfer function significantly increased the estimation accuracy. The relative errors of total amount leached were <7% with the N transformations included, but up to 17% without including the transformation processes.
Efficacy of Alum and Coal Combustion By‐Products in Stabilizing Manure Phosphorus
Authors: Dou Z. , Zhang G. Y. , Stout W. L. , Toth J. D. , Ferguson J. D. 
Published: June 2010

ABSTRACTAnimal manures contain large amounts of soluble phosphorus (P), which is prone to runoff losses when manure is surface‐applied. Here we report the efficacy of alum and three coal combustion by‐products in reducing P solubility when added to dairy, swine, or broiler litter manures in a laboratory incubation study. Compared with unamended controls, alum effectively reduced readily soluble P, determined in water extracts of moist manure samples with 1 h of shaking, for all three manures. The reduction ranged from 80 to 99% at treatment rates of 100 to 250 g alum kg−1manure dry matter. The fluidized bed combustion fly ash (FBC) reduced readily soluble P by 50 to 60% at a rate of 400 g kg−1for all three manures. Flue gas desulfurization by‐product (FGD) reduced readily soluble P by nearly 80% when added to swine manure and broiler litter at 150 and 250 g kg−1Another by‐product, anthracite refuse fly ash (ANT), was ineffective for all three manures. In all cases, reduction in readily soluble P is primarily associated with inorganic phosphorus (Pi) with little change in organic phosphorus (Po). Sequential extraction results indicate that the by‐product treatments shifted manure P from H2O‐P into a less vulnerable fraction, NaHCO3−P, while the alum treatment shifted the P into even more stable forms, mostly NaOH‐P. Such shifts in P fractions would have little influence on P availability for crops over the long term but would retard and reduce potential losses of P following manure applications.
Fate of Coliform Bacteria in Composted Beef Cattle Feedlot Manure
Authors: Larney Francis J. , Yanke L. Jay , Miller James J. , McAllister Tim A. 
Published: June 2010

ABSTRACTThe link between livestock production, manure management, and human health has received much public attention in recent years. Composting is often promoted as a means of sanitizing manure to ensure that pathogenic bacteria are not spread to a wider environment during land application. In a two‐year study (1998 and 1999) in southern Alberta, we examined the fate of coliform bacteria during windrow composting of cattle (Bos taurus) manure from feedlot pens bedded with cereal straw or wood chips. Numbers of total coliforms (TC) and Escherichia coli declined as the composting period progressed. In 1998, TC levels (mean of both bedding types) were log10 7.86 cells g−1 dry wt. for raw manure on Day 0, log10 3.38 cells g−1 by Day 7, and log10 1.69 cells g−1 by Day 14. More than 99.9% of TC and E. coli was eliminated in the first 7 d when average windrow temperatures ranged from 33.5 to 41.5°C. The type of bedding did not influence the numbers of TC or E. coli Dessication probably played a minor role in coliform elimination, since water loss was low (<0.07 kg kg−1) in the first 7 d of composting. However, total aerobic heterotroph populations remained high (>7.0 log10 CFU g−1 dry wt., where CFU is colony forming units) throughout the composting period, possibly causing an antagonistic effect. Land application of compost, with its nondetectable levels of E. coli compared with raw manure, should minimize environmental risk in areas of intensive livestock production.
Advanced Solid‐State Carbon‐13 Nuclear Magnetic Resonance Spectroscopic Studies of Sewage Sludge Organic Matter
Authors: Smernik Ronald J. , Oliver Ian W. , Merrington Graham 
Published: June 2010

ABSTRACTTwo novel solid‐state 13C nuclear magnetic resonance (NMR) spectroscopic techniques, PSRE (proton spin relaxation editing) and RESTORE [Restoration of Spectra via TCH and T1ρH (T One Rho H) Editing], were used to provide detailed chemical characterization of the organic matter from six Australian sewage sludges. These methods were used to probe the submicrometer heterogeneity of sludge organic matter, and identify and quantify spatially distinct components. Analysis of the T1H relaxation behavior of the sludges indicated that each sludge contained two types of organic domains. Carbon‐13 PSRE NMR subspectra were generated to determine the chemical nature of these domains. The rapidly relaxing component of each sludge was rich in protein and alkyl carbon, and was identified as dead bacterial material. The slowly relaxing component of each sludge was rich in carbohydrate and lignin structures, and was identified as partly degraded plant material. The bacterial domains were shown, using the RESTORE technique, to also have characteristically rapid T1ρH relaxation rates. This rapid T1ρH relaxation was identified as the main cause of underrepresentation of these domains in standard 13C cross polarization (CP) NMR spectra of sludges. The heterogeneous nature of sewage sludge organic matter has implications for land application of sewage sludge, since the two components are likely to have different capacities for sorbing organic and inorganic toxicants present in sewage sludge, and will decompose at different rates.
Predicting and Measuring Environmental Concentration of Pesticides in Air after Soil Application
Authors: Ferrari Federico , Trevisan Marco , Capri Ettore 
Published: June 2010

ABSTRACTPesticides can volatilize into the atmosphere, which affects the air quality. The ability to predict pesticide volatilization is an essential tool for human risk and environmental assessment. Even though there are several mathematical models to assess and predict the fate of pesticides in different compartments of the environment, there is no reliable model to predict volatilization. The objectives of this study were to evaluate pesticide volatilization under agricultural conditions using malathion [O,O‐dimethyl‐S‐(1,2‐dicarbethoxyethyl)‐dithiophosphate], ethoprophos (O‐ethyl S,S‐dipropylphosphorodithioate), and procymidone [N‐(3,5‐dichlorophenyl)‐1,2‐dimethylcyclopropane‐1,2‐dicarboximide] as test compounds and to evaluate the ability of the Pesticide Leaching Model (PELMO) to calculate the predicted environmental concentrations of pesticides in air under field conditions. The volatilization rate of procymidone, malathion, and ethoprophos was determined in a field study during two different periods (December 1998 and September 1999) using the Theoretical Profile Shape (TPS) method. The experiments were performed on bare silty soil in the Bologna province, Italy. Residues in the air were continuously monitored for 2 to 3 wk after the pesticide applications. The amount of pesticide volatilized was 16, 5, and 11% in December 1998 and 41, 23, and 19% in September 1999 for procymidone, malathion, and ethoprophos, respectively. In both these experiments, the PELMO simulations of the concentration of ethoprophos and procymidone were in good agreement with the measured data (factor ± 1.1 on average). The volatilization of malathion was underestimated by a factor of 30 on average. These results suggest that volatilization described by PELMO may be reliable for volatile substances, but PELMO may underpredict volatilization for less‐volatile substances.
Simple Protocols to Determine Dust Potentials from Cattle Feedlot Soil and Surface Samples
Authors: Miller Daniel N. , Woodbury Bryan L. 
Published: June 2010

ABSTRACTCattle feedlot dust is an annoyance and may be a route for nutrient transport, odor emission, and pathogen dispersion, but important environmental factors that contribute to dust emissions are poorly characterized. A general protocol was devised to test feedlot samples for their ability to produce dust under a variety of environmental conditions. A blender was modified to produce dust from a variety of dried feedlot surface and soil samples and collect airborne particles on glass fiber filters by vacuum collection. A general blending protocol optimized for sample volume (150–175 cm3), blending time (5 min of pre‐blending), and dust collection time (15 s) provided consistent dust measurements for all samples tested. The procedure performed well on samples that varied in organic matter content, but was restricted to samples containing less than 200 to 700 g H2O kg−1 dry matter (DM). When applied to field samples, the technique demonstrated considerable spatial variability between feedlot pen sites. Mechanistically, dust potential was related to moisture and organic matter content. An alternative protocol also demonstrated differences within pen sites in maximum dust potential and dust airborne residence time. The two protocols were not intended, nor are they suitable, for predicting actual particulate matter emissions from agricultural sources. Rather, the protocols rapidly and inexpensively compared the potential for dust emission from samples of differing composition under a variety of environmental conditions.
Phenanthrene Sorption to Structurally Modified Humic Acids
Authors: Simpson Myrna J. , Chefetz Benny , Hatcher Patrick G. 
Published: June 2010

ABSTRACTSeveral studies emphasize the importance of soil organic matter characteristics in hydrophobic contaminant sorption and outline the strong dependence of sorption on organic matter aromaticity. In this study, the role of organic matter aromaticity in phenanthrene sorption was investigated using humic acids (HAs) from compost, peat, and soil that were structurally modified by bleaching, hydrolysis, oximation, and subcritical water extraction. The HAs were characterized with cross polarization magic angle spinning carbon‐13 nuclear magnetic resonance (CPMAS13C NMR) spectroscopy and used in batch equilibrations with phenanthrene. Bleaching substantially reduced the aromaticity of the samples whereas the other treatments increased the relative aromaticity. Phenanthrene sorption increased, even though there was a substantial reduction in sorbent aromaticity with some samples. The HAs that exhibited comparable CPMAS13C NMR spectra and aromaticity did not behave similarly with respect to phenanthrene sorption. When the sorption data (Kocvalues) were correlated to sample aromaticity, the correlation coefficients (r2) did not exceed 0.39. Comparisons with the atomic H to C ratio provided slightly betterr2values (up to 0.54). This study demonstrates that macroscopic sorbent characteristics could not explain the observed phenanthrene sorption coefficients, aliphatic structural components of HAs can contribute appreciably to phenanthrene sorption, and organic matter physical conformation may regulate access to organic matter structures. Therefore, the use of only macroscopic sorbent properties, such as aromaticity, to predict and rationalize sorption values cannot solely be used to explain the behavior of organic contaminants in soil environments.
Impact of Dissolved Organic Matter on Copper Mobility in Aquifer Material
Authors: Han Nizhou , Thompson Michael L. 
Published: June 2010

ABSTRACTNaturally occurring dissolved organic matter (DOM) and biosolids‐derived DOM have been implicated in the mobility of metals in soils and aquifer materials. To investigate the effect of DOM on copper mobility in aquifer material, DOM derived from sewage biosolids was separated into two apparent molecular‐weight (MW) fractions, 500 to 3500 Da (LMW) and >14000 Da (HMW). In each MW fraction, the DOM was further fractionated into hydrophilic, hydrophobic acid, and hydrophobic neutral compounds by an XAD‐8 chromatography technique. The mobility of these DOM components and their influences on copper transport in a sesquioxide‐coated, sandy aquifer material were examined with column transport experiments. The LMW DOM was found to be highly mobile, whereas the HMW DOM had a greater tendency to be retained by the aquifer material. Within the same MW fraction, the mobility of DOM followed the order of hydrophilic DOM > hydrophobic acid DOM > hydrophobic neutral DOM. Copper breakthrough curves in the presence of various DOM components showed that, except for the HMW hydrophilic fraction, DOM components enhanced Cu transport through the aquifer columns at early stages of transport (the first 75 pore volumes). In the later stages, however, all the DOM components substantially inhibited Cu mobility. We hypothesize that several mechanisms could account for retardation of Cu movement in the presence of the DOM fractions, including the formation of ternary complexes between the aquifer material, Cu, and DOM; changes in the electrostatic potential at the solid‐phase surface; and pH buffering by DOM.
Rainfall Timing and Frequency Influence on Leaching of Escherichia coli RS2G through Soil Following Manure Application
Authors: Saini R. , Halverson L. J. , Lorimor J. C. 
Published: June 2010

ABSTRACTThe time between swine (Sus scrofa) manure application to soil as a crop fertilizer, the first rainfall event, and the frequency of rainfall events should influence leaching potential of fecal pathogens. Soil microcosms were inoculated in the lab with a swine manure isolate of Escherichia coli, strain RS2G, expressing green fluorescent protein, to examine how timing and frequency of rainfall events influences RS2G leaching and survival in soil. Liquid swine manure inoculated with RS2G was applied to intact soil cores (20 cm in diameter × 30 cm long) 4, 8, or 16 d before the first rainfall event (50.8 mm over a 4‐h period), and each core received one to three rainfall events. Manure application methods (no‐till surface‐broadcast, broadcast and incorporated, and tilled before broadcast) had no affect on leaching, although there was greater survival in soils when the manure had been incorporated. Most of the RS2G in the leachate appeared following the first rainfall event and RS2G leaching decreased with increasing time between manure application and the first rainfall, although leachates contained as much as 3.4 to 4.5 log colony forming units (CFU) 100 mL−1 of RS2G when the first rainfall occurred 16 d after manure application. With increasing frequency of rainfalls there was a decrease in subsequent concentrations of RS2G in the leachate. There was no correlation between leachate RS2G and total coliforms or fecal streptococci concentrations. Soil RS2G numbers were 1 to 10% of the inoculum regardless of the length of time between manure application and the first rainfall. RS2G leaching was mostly influenced by the time between manure application and first rainfall event, and significant leaching and survival in soil was possible even if the first rain occurred 16 d after manure application.
Bedding and Seasonal Effects on Chemical and Bacterial Properties of Feedlot Cattle Manure
Authors: Miller Jim J. , Beasley Bruce W. , Yanke L. Jay , Larney Francis J. , McAllister Tim A. , Olson Barry M. , Selinger L. Brent , Chanasyk David S. , Hasselback Paul 
Published: June 2010

ABSTRACTNutrients, soluble salts, and pathogenic bacteria in feedlot‐pen manure have the potential to cause pollution of the environment. A three‐year study (1998–2000) was conducted at a beef cattle (Bos taurus) feedlot in southern Alberta, Canada to determine the effect of bedding material [barley (Hordeum vulgare L.) straw versus wood chips] and season on the chemical and bacterial properties of pen‐floor manure. Manure was sampled for chemical content (N, P, soluble salts, electrical conductivity, and pH) and populations of four groups of bacteria (Escherichia coli, total coliforms, and total aerobic heterotrophs at 27 and 39°C). More chemical parameters of manure were significantly (P ≤ 0.05) affected by season (SO4, Na, Mg, K, Ca, sodium adsorption ratio [SAR], total C, NO3–N, NH4–N, total P, and available P) than by bedding (K, pH, total C, C to N ratio, NH4–N, and available P). Bedding had no significant (P > 0.05) effect on the four bacterial groups whereas season affected all four groups. Numbers of E. coli and total coliforms (TC) were significantly higher by 1.72 to 2.02 log10 units in the summer than the other three seasons, which was consistent with a strong positive correlation of E. coli and TC with air temperature. The low ratio of bedding to manure in the pens was probably the major cause of the lack of significant bedding effects. Bedding material and seasonal timing of cleaning feedlot pens and land application of manure may be a potential tool to manage nutrients, soluble salts, and pathogens in manure.
Gas‐Phase Sorption–Desorption of Propargyl Bromide and 1,3‐Dichloropropene on Plastic Materials
Authors: Allaire S. E. , Yates S. R. , Ernst F. , Papiernik S. K. 
Published: June 2010

ABSTRACTThe goal of this research was to provide information for choosing appropriate materials for studying gas‐phase concentrations of propargyl bromide (3BP) and 1,3‐dichloropropene (1,3‐D) in laboratory experiments. Several materials were tested and found to sorb both gas‐phase chemicals in the following order: stainless steel (SS) < Teflon polytetrafluoroethylene (PTFE‐FEP) ≈ flexible polyvinyl chloride (PVC) ≈ acrylic < low‐density polyethylene (PE) < vinyl ≈ silicone < polyurethane foam (PUF). Sorption of SS was insignificant and PUF sorbed all the fumigant that was applied. For the other materials, linear sorption coefficients (Kd) for 3BP ranged from 3.0 cm3 g−1 for PVC to 215 cm3 g−1 for silicone. Freundlich sorption coefficients for 1,3‐D ranged from 11.5 to 371 cm3 g−1 First‐order desorption rate constants in an open system ranged from 0.05 to 1.38 h−1 for 3BP and from 0.07 to 1.73 h−1 for 1,3‐D. In a closed system, less than 2% of sorbed fumigant desorbed from vinyl while up to 99% desorbed from PVC within 24 h when equilibrated at the highest headspace concentration. Sorption of both fumigants was linearly related to the square root of time except for vinyl and silicone. This may indicate non‐fickian diffusion of fumigant into the polymer matrix. Vinyl, silicone, PE, and PUF should be avoided for quantitative study of organic gases, except possibly as a trapping medium. Use of PTFE, PVC, and acrylic may require correction for sorption–desorption and diffusion.
Phosphorus Restrictions for Land Application of Biosolids
Authors: Shober Amy L. , Sims J. Thomas 
Published: June 2010

ABSTRACTThe application of biosolids (sewage sludge) to agricultural soils provides P in excess of crop needs when applied to meet the N needs of most agronomic crops. These overapplications can result in the buildup of P in soils to values well above those needed for optimum crop yields and also may increase risk of P losses to surface and ground waters. Because of concerns regarding the influence of P on water quality in the USA, many state and federal agencies now recommend or require P‐based nutrient management plans for animal manures. Similar actions are now under consideration for the land application of biosolids. We reviewed the literature on this subject and conducted a national survey to determine if states had restrictions on P levels in biosolids‐amended soils. The literature review indicates that while the current N‐based approach to biosolids management does result in increases of soil P, some properties of biosolids may mitigate the environmental risk to water quality associated with land application of P in biosolids. Results of the survey showed that 24 states have regulations or guidelines that can be imposed to restrict land application of biosolids based on P. Many of these states use numerical thresholds for P in biosolids‐amended soils that are based on soil test phosphorus (STP) values that are much greater than the values considered to be agronomically beneficial. We suggest there is the need for a comprehensive environmental risk assessment of biosolids P. If risk assessment suggests the need for regulation of biosolids application, we suggest regulations be based on the P Site Index (PSI), which is the method being used by most states for animal manure management.
Spatial Variability of Nitrous Oxide Emissions and Their Soil‐Related Determining Factors in an Agricultural Field
Authors: Yanai Junta , Sawamoto Takuji , Oe Taku , Kusa Kanako , Yamakawa Keisuke , Sakamoto Kazunori , Naganawa Takahiko , Inubushi Kazuyuki , Hatano Ryusuke , Kosaki Takashi 
Published: June 2010

ABSTRACTTo evaluate spatial variability of nitrous oxide (N2O) emissions and to elucidate their determining factors on a field‐scale basis, N2O fluxes and various soil properties were evaluated in a 100‐ × 100‐m onion (Allium cepa L.) field. Nitrous oxide fluxes were determined by a closed chamber method from the one‐hundred 10‐ × 10‐m plots. Physical (e.g., bulk density and water content), chemical (e.g., total N and pH), and biological (e.g., microbial biomass C and N) properties were determined from surface soil samples (0–0.1 m) of each plot. Geostatistical analysis was performed to examine spatial variability of both N2O fluxes and soil properties. Multivariate analysis was also conducted to elucidate relationships between soil properties and observed fluxes. Nitrous oxide fluxes were highly variable (average 331 μg N m−2 h−1, CV 217%) and were log–normally distributed. Log‐transformed N2O fluxes had moderate spatial dependence with a range of >75 m. High N2O fluxes were observed at sites with relatively low elevation. Multivariate analysis indicated that an organic matter factor and a pH factor of the principal component analysis were the main soil‐related determining factors of log‐transformed N2O fluxes. By combining multivariate analysis with geostatistics, a map of predicted N2O fluxes closely matched the spatial pattern of measured fluxes. The regression equation based on the soil properties explained 56% of the spatially structured variation of the log‐transformed N2O fluxes. Site‐specific management to regulate organic matter content and water status of a soil could be a promising means of reducing N2O emissions from agricultural fields.