bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sorption of Thiazafluron by Iron‐ and Humic Acid‐Coated Montmorillonite
Authors: Celis R. , Cox L. , Hermosin M. C. , Cornejo J. 
Published: July 2010

AbstractThe intimate association between the different soil constituents may determine the sorptive behavior of soil aggregates. This study was conducted to study the influence of interassociation on the sorption capacity of montmorillonite for the polar uncharged herbicide thiazafluron (1,3‐dimethyl‐1‐(5‐trifluormethyl‐1,3,4‐thiadiazol‐2‐yl)urea). Calcium Wyoming montmorillonite was coated with iron species and humic macromolecules and sorption of thiazafluron determined and compared with that for the uncoated clay. The presence of precipitated Fe(III)‐OH‐species on montmorillonite gave rise to an increase in the specific surface area measured by N adsorption (from 18–45 m2 g−1) and to a decrease in the sorption of thiazafluron by the clay (from 156.9‐110.8 mmol kg−1). Both commercial and soil humic acid also decreased the sorption of thiazafluron by montmorillonite, but the decrease was higher in the case of soil humic acid (from 100.3‐77.0 mmol kg−1), which was more associated with the clay. Iron and organic matter removal from the clay surface increased again the sorption of the herbicide thiazafluron by montmorillonite. The results of this work show that mineral and organic coatings on clays alter the nature of the surface exposed for sorption of organics, thus affecting the sorption behavior of colloidal soil particles.
The Clean Water Act and Animal Agriculture
Authors: Martin John H. 
Published: July 2010

AbstractHistorically, impacts of agricultural activities on water quality, including animal production, generally were considered to be natural and uncontrollable. In the 1960s, this view began to change in response to public concern about highly visible incidents such as massive fish kills in the Midwest and shellfish bed closures on Long Island, NY, caused respectively by beef cattle feedlot runoff and the duck industry. Ultimately, these incidents led to the designation in the Federal Water Pollution Control Act Amendments of 1972 of feedlots as a point source category of water pollutants subject to regulation under the National Pollutant Discharge Elimination System permit program. The regulatory program that evolved is complex and confusing and is not well understood by many livestock and poultry producers. The transition from a narrow focus on pollutant discharges from confinement facilities to a broader scope has contributed to the confusing nature of this program. Included now are pollutant discharges traditionally viewed as nonpoint in character. An example of the broadening in scope of this program is a recent appellate decision holding that runoff from cropland used for disposal of manure from a facility designated as a point source also was a point source discharge of pollutants. Although this decision is consistent with the USEPA's claim of regulatory authority, it is not clear that it is consistent with the original intent of Congress. The decision, along with the general complexity and confusing nature of this regulatory program, suggests that revision is needed.
Boron Contents and Isotopic Compositions of Hog Manure, Selected Fertilizers, and Water in Minnesota
Authors: Komor S. C. 
Published: July 2010

AbstractBoron‐isotope (δ11B) values may be useful as surrogate tracers of contaminants and indicators of water mixing in agricultural settings. This paper characterizes the B contents and isotopic compositions of hog manure and selected fertilizers, and presents δ11B data for ground and surface water from two agricultural areas. Boron concentrations in dry hog manure averaged 61 mg/kg and in commercial fertilizers ranged from below detection limits in some brands of ammonium nitrate and urea to 382 mg/kg in magnesium sulfate. Values of δ11B of untreated hog manure ranged from 7.2 to 11.2‰ and of N fertilizers were −2.0 to 0.7‰. In 22 groundwater samples from a sand‐plain aquifer in east‐central Minnesota, B concentrations averaged 0.04 mg/L and δ11B values ranged from 2.3 to 41.5‰. Groundwater beneath a hog feedlot and a cultivated field where hog manure was applied had B‐isotope compositions consistent with the water containing hog‐manure leachate. In a 775‐km2 watershed with silty‐loam soils in southcentral Minnesota: 18 samples of subsurface drainage from corn (Zea mays L.) and soybean (Glycine max L. Merr.) fields had average B concentrations of 0.06 mg/L and δ11B values of 5.3 to 15.1‰; 27 stream samples had average B concentrations of 0.05 mg/L and δ11B values of 1.0 to 19.0‰; and eight groundwater samples had average B concentrations of 0.09 mg/L and δ11B values of −0.3 to 23.0‰. Values of δ11B and B concentrations, when plotted against one another, define a curved mixing trend that suggests subsurface drainage and stream water contain mixtures of B from shallow and deep groundwater.
Nitrate Losses through Subsurface Tile Drainage in Conservation Reserve Program, Alfalfa, and Row Crop Systems
Authors: Randall G. W. , Huggins D. R. , Russelle M. P. , Fuchs D. J. , Nelson W. W. , Anderson J. L. 
Published: July 2010

AbstractSubsurface drainage of gravitational water from the soil profile through tiles is a common practice used to improve crop production on poorly drained soils. Previous research has often shown significant concentrations of nitrate‐N (NO3‐N) in drainage water from row‐crop systems, but little drainage research has been conducted under perennial crops such as those used in the Conservation Reserve Program (CRP). Four cropping systems (continuous corn, a corn‐soybean rotation, alfalfa, and CRP) were established in 1988 to determine aboveground biomass yields, N uptake, residual soil N (RSN), soil water content, and NO3 losses to subsurface tile drainage water as influenced by cropping system. Hydrologic‐year rainfall during the 6‐yr study ranged from 23% below normal to 66% above normal. In dry years, yields were limited, RSN accumulated at elevated levels in all crop systems but especially in the row‐crop systems, soil water reserves and RSN were reduced to as deep as 2.7 m in the alfalfa (Medicago sativa L.) and CRP systems, and tile drainage did not occur. Drainage occurred only in the corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] systems in the year of normal rainfall. In years of excess precipitation, drainage from the row‐crop systems exceeded that from the perennial crops by 1.1 to 5.3X. Flow‐weighted average NO3‐N concentrations in the water during the flow period of this study were continuous corn = 32, corn‐soybean rotation = 24, alfalfa = 3 and CRP = 2 mg/L. Nitrate losses in the subsurface drainage water from the continuous corn and corn‐soybean systems were about 37X and 35X higher, respectively, than from the alfalfa and CRP systems due primarily to greater season‐long ET resulting in less drainage and greater uptake and/or immobilization of N by the perennial crops.
Impact of Alternative Farm Management Practices on Nitrogen Pollution of Groundwater: Evaluation and Application of CENTURY Model
Authors: Yiridoe Emmanuel K. , Voroney R. Paul , Weersink Alfons 
Published: July 2010

AbstractAn important environmental issue for Canadian agriculture is groundwater‐N pollution. Addressing this issue requires understanding the impact of farm management practices on nitrate leaching, but empirical studies are limited by resource and time constraints. The CENTURY model was adapted to southwestern Ontario agricultural conditions and then used to predict short‐ to medium‐term effects of crop choice and crop rotation pattern, fertilizer management, and tillage practice on N leaching. CENTURY model evaluation suggests that aboveground C production (translated into grain yield) and N leaching predicted by CENTURY provide good representation of results from actual field‐measured data. Results suggest that relative reduction in groundwater‐N leached is markedly greater at higher rates of fertilizer application than at lower (below the maximum economic rate of N fertilization) rates. Although tillage may not dramatically affect N leaching, other farm management practices such as crop type and crop rotation choice, along with the carry‐over effects of these management activities on mineralization of soil organic matter, may have a significant effect on N leaching from the root zone.
Adsorption of Imazethapyr to Amended and Nonamended Soils and Humic Acids
Authors: Senesi Nicola , La Cava Paolo , Miano Teodoro M. 
Published: July 2010

AbstractSoil amendment with municipal sewage sludge affects the total amount and chemical nature of soil organic matter, including its humic acid (HA) component. These effects are expected to modify the quantitative and mechanistic aspects of herbicide adsorption to soil. The magnitude and mechanisms of adsorption of the imidazolinone herbicide, imazethapyr, to sewage‐sludge amended and nonamended soils, and their HA components, were studied using a batch equilibrium method coupled with high‐pressure liquid chromatography, and by Fourier‐transform infrared (FT‐IR), fluorescence and electron spin resonance (ESR) spectroscopic techniques. Sludge‐amended soils exhibited nonlinear, L‐shaped adsorption isotherms, and much higher adsorption capacity than nonamended soils, which had linear isotherms. Soil‐solated HAs had nonlinear, L‐shaped isotherms and adsorbed imazethapyr in amounts much higher than the corresponding whole soils. Spectroscopic data indicate that imazethapyr may interact with HAs through multiple‐binding mechanisms including ionic, charge‐transfer, and hydrogen bonds. Results of this work indicate that organic matter applied as sludge amendment to soil is able to increase the magnitude and modify the mechanism of imazethapyr adsorption to soil, and confirms the prominent role played by HAs in this process.
Sorption Behavior and Competition of Bromacil, Napropamide, and Prometryn
Authors: Turin H. J. , Bowman R. S. 
Published: July 2010

AbstractGroundwater contamination by pesticides is a problem of major and increasing concern. Detailed field measurements reveal that leaching of pesticides from soils is often faster than predicted using simple models. This discrepancy is likely due to a combination of physical effects (e.g., preferential pathways) and complexities in the chemical sorption process. To address the issue of sorption complexity, a series of laboratory batch sorption studies have been conducted to determine the detailed sorption behavior of three herbicides, bromacil [5‐bromo‐6‐methyl‐3‐(1‐methylpropyl)‐2,4(1H,3H)pyrimidinedione], napropamide [N,N‐diethyl‐2‐(1‐naphthalenyloxy)propanamide], and prometryn [N,N′‐bis(1‐methylethyl)‐6‐(methylthio)‐1,3,5‐triazine‐2,4‐diamine], onto a sandy loam soil. The studies were designed to determine the extent of nonideal sorption behavior, specifically nonequilibrium, nonlinearity, sorption hysteresis, and solute‐solute interactions. Results showed all three herbicides reached sorption equilibrium quickly, within 2 h. Both napropamide and prometryn were linearly sorbed, while bromacil sorption followed a Freundlich isotherm, with n = 0.92. All three herbicides displayed apparent sorption hysteresis. Bromacil and napropamide sorption decreased in the presence of the other herbicides, while prometryn sorption was unaffected. Contrary to most literature data, napropamide was more strongly sorbed than prometryn in these studies, due to the high pH of the soil. Results suggest that sorption nonlinearity and competition may increase field‐scale transport velocities by 10% or more.
Papermill Sludge Amendments, Tree Protection, and Tree Establishment on an Abandoned Coal Minesoil
Authors: Kost D. A. , Boutelle D. A. , Larson M. M. , Smith W. D. , Vimmerstedt J. P. 
Published: July 2010

AbstractWe measured survival, growth, and foliar nutrition of white ash (Fraxinus americana L.), sycamore (Platanus occidentalis L.), and black walnut (Juglans nigra L.) on a regraded minesoil (Typic Udorthent, pH 2.9) treated with four combinations of papermill sludge depth by incorporation methods. We also compared tree performance when protected from mammal damage by tube, netting, or no shelters. Sludge rates were approximately 860 Mg ha−1 for a 15‐cm depth and 3450 Mg ha−1 for a 60‐cm depth. After 4 yr, tree survival was 65% when either 15 or 60 cm of sludge was deep incorporated by a backhoe. Survival was 43% if 15 cm of sludge was rototill incorporated and 3% if 45 cm of sludge was surface applied over the rototiller‐incorporated sludge (60 cm total sludge depth). Trees were tallest (236 cm) on 15 cm‐backhoed, intermediate (204 cm) on 60 cm backhoed, and shortest (130 cm) on 15 cm rotilled treatments. Ash (56% survival) survived better than sycamore (40%) and walnut (36%). Tree survival was best (61%) in tubes, intermediate (43%) in nets, and worst (28%) with no protection. Ash and walnut were tallest (177 cm) in tubes, intermediate (124 cm) in nets, and shortest (103 cm) with no protection. Sycamore height (305 cm) was not affected by the shelters. Foliar nutrition of trees was adequate except for possible low P in ash. In summary, tree survival and growth were good if sludge was incorporated by backhoeing and trees were protected by tube shelters.
Evaluation of Leachate Quality from Codisposed Coal Fly Ash and Coal Refuse
Authors: Stewart Barry R. , Daniels W. Lee , Jackson Meral L. 
Published: July 2010

AbstractThe exclusion of coal fly ash from regulation as a hazardous waste has led to increased interest in returning ash to the coal fields for disposal. Bulk blending alkaline fly ash with acid forming coal refuse may present a disposal option that also aids in the control of acid mine drainage (AMD). A column leaching study was initiated to examine the leachate quality from acid forming coal refuse‐fly ash blends. Coal refuse alone (2.2% total S), and bulk blended coal refuse and alkaline fly ash (20 and 33% ash, w/w) were packed into 20‐cm diameter leaching columns and run under unsaturated conditions for over 4 yr. Leachates were analyzed for pH, electrical conductivity, Fe, Mn, and SO2−4 content. The coal refuse columns acidified quickly and produced leachates that, at peak levels, contained high contents of acidity (pH 1.6), Fe (10 000 mg L−1), SO2−4 (30 000 mg L−1), and Mn (300 mg L−1). The high levels of metals in these leachates decreased over time. The ash‐treated columns maintained leachate pH values near 8.0 with very low metal levels. The bulk mixing of alkaline fly ash and coal refuse, at high blending rates (>20%), appears to an effective codisposal option that also provides long‐term AMD control. Only B and SO2−4 appeared to leach at any significant level and the quality of leachates from the ash‐treated columns was significantly improved with respect to the untreated coal refuse.
Phytotoxicity and Plant Uptake of Fuel Oil Hydrocarbons
Authors: Chaîneau C. H. , Morel J. L. , Oudot J. 
Published: July 2010

AbstractThe phytotoxicity and phytoavailability of hydrocarbons (HC) were studied in soils artificially contaminated with fuel oil. The presence of HC in the soil inhibited seed germination and reduced plant growth. The germination and development of cultivated plants varied with the chemical structure of HC, the HC concentration in soil, and the plant species. The LC50 values for germination after 8 d in the presence of a fuel oil varied from 0.3 to 4% (oil/soil, w/w) for lettuce (Lactuca sativa L.), barley (Hordeum vulgare L.), clover (Trifolium repens L.), and maize (Zea mays L.) and from 4 to 9% for bean (Phaseolus vulgaris L.), wheat (Triticum aestivum L.), and sunflower (Helianthus annuus L.). Light aromatics and naphtas were the most phytotoxic HC. The inhibition of plant growth increased with HC concentration but was not linearly proportional to the loading rate. Reduction in aerial biomass was >80% for wheat and bean at a concentration of 0.3% and <30% for maize at 1.2%. No saturated nor aromatic fuel oil HC was detected by gas‐chromatography in the stems and leaves of maize grown during 110 d on 1.2% oil‐contaminated soil, indicating that no uptake of HC from soils occurred.
Cadmium Sorption and Desorption in Limed Topsoils as Influenced by pH: Isotherms and Simulated Leaching
Authors: Filius Angelika , Streck Thilo , Richter Jörg 
Published: July 2010

AbstractThe influence of pH on cadmium (Cd) sorption and desorption isotherms was studied in sandy and clayey soils of northern Germany. Seventeen topsoils from four long‐term lime amendment experiment plots ranging in pH from 4.1 to 6.9 were collected. Batch adsorption isotherms demonstrated the strong influence of pH on Cd sorption behavior. Cadmium sorption increased with pH, even within a very narrow range of pH values (ΔpH ≈ 0.3). The experimental desorption isotherms, which were determined by widening the soil/solution ratio, differed markedly from the adsorption isotherms. Differences decreased when reaction time for desorption was prolonged. The data for Cd adsorption and desorption were pooled to derive the coefficients of a generalized Freundlich‐type expression S = S(CM) including soil pH in 0.01 M CaCl2 and organic C content (oc) (% by mass) (S = k* (H+)a ocb CM). Sorption isotherms were used for simulations to predict vertical displacement of Cd in the field. The simulations using measured field mean concentration profiles S(z) as initial values, showed Cd adsorption isotherms to be appropriate for describing longer‐term desorption equilibria.
Solubility and Plant Uptake of Metals with and without Liming of Sludge‐Amended Soils
Authors: Krebs R. , Gupta S. K. , Furrer G. , Schulin R. 
Published: July 2010

AbstractExcessive applications of sewage sludge and pig manure have led to the accumulation of potentially toxic elements in soils. The objective of this study was to examine the NaNO3 extractability of Cu, Zn, and Cd with time and in relation to soil pH and soil organic matter content and to investigate the concentrations of these metals in pea (Pisum arvense L.) as a result of liming. The field study was conducted on an orthic luvisol with pig manure and sewage sludge application rates of 5 t dry organic matter ha−1 yr−1 from 1976 to 1984. After 1984, all field plots were equally treated with mineral fertilizers and in 1991, lime was added to half of each plot. The soil pH decreased in all unlimcd treatments about half a unit from 1985 to 1994. Concurrently, the Zn and Cd concentrations extractable with 0.1 M NaNO3 increased as well as the Cd concentrations in field pea. Liming raised the soil pH by approximately one unit to 6.4 and 6.9 in pig manure‐ and sewage sludge‐treated plots, respectively and resulted in decreasing concentrations of Cu, Zn, and Cd in seeds and crop residues of field pea. The results suggested that plant uptake and solubility of Zn, Cu, and Cd can continue to be higher in sewage sludge‐ and pig manure‐treated soils than in control plots during a 10‐yr period after the applications were ceased. Liming most effectively reduces the solubility and the plant uptake of Zn and Cd.
Adsorption and Desorption of Atrazine, Deethylatrazine, and Hydroxyatrazine by Soil Components
Authors: Moreau‐Kervévan C. , Mouvet C. 
Published: July 2010

AbstractWe studied the behavior of atrazine (AT), deethylatrazinc (DEA), and hydroxyatrazinc (HyA) in contact with humic acid, kaolinite, smectite, goethite, and ferrihydrite through adsorption kinetics and isotherms, and desorption isotherms, in laboratory batch systems. The initial triazine concentrations in solution ranged from 0.001 to 1 mg L−1. The adsorption of the three triazines by each component was significant (except for AT and DEA by the two iron oxides) and the adsorption equilibrium was reached after 72 h. The adsorption isotherms were described by Freundlich equations. Adsorption increased in the order iron oxides < clays < humic acid. On the humic acid and smectite, adsorption increased in the order DEA < AT ≪ HyA, whereas on kaolinite it increased in the order AT < DEA ≪ HyA. The desorption of the three triazines from each component was hysteretic. For each triazine, the amount of nonextractable residue (NER) followed the order kaolinite ~ smectitc < humic acid. On humic acid, the amount of NER increased in the order DEA < AT < HyA, whereas on the clays it increased in the order AT < DEA < HyA. The results demonstrate: (i) the coexistence of heterogeneous adsorption sites on each soil component, (ii) the importance of the intrinsic characteristics of the triazine (e.g., its pKa) (iii) the likely time‐dependent nature of hysteresis, and (iv) varying amounts of NER resulting from a combination of the number of adsorption sites occupied by the molecule and the energy level of the adsorption mechanisms involved.
Effects of Metam Sodium Fumigation on Soil Microbial Activity and Community Structure
Authors: Macalady J. L. , Fuller M. E. , Scow K. M. 
Published: July 2010

AbstractMetam sodium (MS) is a widely used soil fumigant with broad biocidal activity. The impact of MS on soil microbial community structure and function is largely unknown. We investigated the effects of fumigation with field‐relevant doses of MS in soil microcosms using traditional heterotrophic activity measures (C and N mineralization), a substrate‐utilization assay, and fatty acid analysis. Our results suggest that fumigation with MS results in persistent changes (at least 18 wk) in heterotrophic activity and fatty acid composition of the microbial biomass. Lack of recovery of heterotrophic activity and changes in fatty acid composition after fumigation suggest that MS has the potential to alter important microbially mediated functions such as nutrient cycling and pollutant degradation. Preliminary fatty acid data suggest that actinomycetes and other gram‐positive organisms may recover preferentially after fumigation with MS. Although community fatty acid analysis shows promise as a screening tool in soil microbial toxicity studies, more detailed information can be obtained from analysis of phospholipid fatty acid (PLFA) and other specific lipid fractions.
A Bed Sediment Sampler for Precise Depth Profiling of Contaminant Concentrations in Aquatic Environments
Authors: Quinn Nigel W. T. , Clyde John R. 
Published: July 2010

AbstractA bed sediment and detritus sampler has been developed for use in aquatic environments, such as in canals, rivers or lakes, for determining precise depth profiles of contaminants. The device is superior to currently available commercial push‐tube and piston samplers in its simplicity, ease of use and its ability to retrieve and extrude sample cores. The sampler has been used with success during the past 12 mo to determine a profile of bed sediment Se concentrations within an earth‐lined canal, alternatively used for conveyance of agricultural drainage and wetland water supply.