bluuebunny/crossref_metadata_2025 huggingface dataset:
Deicing Salt Accumulation and Loss in Highway Snowbanks
Authors: Buttle J. M. , Labadia C. F.
Published: July 2010

Environmental impacts of road deicing salt are well known, although salt pathways following application have rarely been quantified. Deicing salt (NaCl) fate was determined from retention and loss in snow cover adjacent to a 14‐km section of highway in southern Ontario during the 1994–1995 winter. Total salt application was ∼530 Mg (29–74 kg m−1 length). Retention in snow cover in the highway right‐of‐way (ROW) decayed as a power function of distance from the highway, although melting of proximal snowbanks with high salt loads disrupted this pattern. Peak concentrations in snowbanks reached 6506 (Na+) and 9916 (Cl−) mg L−1. Wind transport of salt from the ROW was minor and restricted to relatively exposed sites. Almost all applied NaCl reached the soil surface via (i) direct runoff and infiltration of saline water from the road into the shoulder and ROW, and (ii) transfer of salt to snow cover adjacent to the highway and release during snowmelt. Total salt flux along the two pathways during a 49‐d period was similar. Salt transfer via road runoff occurred during or shortly after application, unlike the intermittent fluxes from snow to soil surfaces in the ROW during this period. The latter were relatively uniform along the highway (3–5 kg m−1 length of highway), accounting for 39 to 65% of applied NaCl. However, magnitude and timing of water and salt fluxes from snow to soil varied within the ROW and should be considered when modeling salt transport to groundwater.
Relationship between Phosphorus Levels in Three Ultisols and Phosphorus Concentrations in Runoff
Authors: Pote D. H. , Daniel T. C. , Nichols D. J. , Sharpley A. N. , Moore P. A. , Miller D. M. , Edwards D. R.
Published: July 2010

Soils that contain high P levels can become a primary source of dissolved reactive P (DRP) in runoff, and thus contribute to accelerated eutrophication of surface waters. In a previous study on Captina soil, several soil test P (STP) methods gave results that were significantly correlated to DRP levels in runoff, but distilled H2O and NH4‐oxalate methods gave the best correlations. Because results might differ on other soils, runoff studies were conducted on three additional Ultisols to identify the most consistent STP method for predicting runoff DRP levels, and determine effects of site hydrology on correlations between STP and runoff DRP concentrations. Surface soil (0–2 cm depth) of pasture plots was analyzed by Mehlich III, Olsen, Morgan, Bray‐Kurtz P1, NH4‐oxalate, and distilled H20 methods. Also, P saturation of each soil was determined by three different methods. Simulated rain (75 mm h−1) produced 30 min of runoff from each plot. All correlations of STP to runoff DRP were significant (P < 0.01) regardless of soil series or STP method, with most STP methods giving high correlations (r > 0.90) on all three soils. For given level of H2O‐extractable STP, low runoff volumes coincided with low DRP concentrations. Therefore, when each DRP concentration was divided by volume of plot runoff, correlations to H2O‐extractable STP had the same (P < 0.05) regression line for every soil. This suggests the importance of site hydrology in determining P loss in runoff, and may provide a means of developing a single relationship for a range of soil series.
Reducing Nitrogen Losses during Simulated Composting of Poultry Manure using Adsorbents or Chemical Amendments
Authors: Kithome M. , Paul J. W. , Bomke A. A.
Published: July 2010

Ammonia emissions during composting of poultry manure can be significant, representing increased environmental pollution and decreased fertilizer value of manure. The objectives of this study were to measure NH3 volatilization losses during composting of poultry layer manure, and to evaluate the potential of different amendments to reduce NH3 losses using a laboratory composting simulator. The poultry manure was treated with various amendments which included two natural zeolites, clay, coir (mesocarp of coconut fruit), CaCl2, CaSO4, MgCl2, MgSO4, and Al2(SO4)3. The manure was composted for 49 to 56 d. Ammonia volatilized from the manure was trapped in a 0.3 M H2SO4 solution. The composts were weighed and analyzed for moisture content, total N and NH+4. The NH3 volatilization loss for the unamended manures ranged from 47 to 62% of the total manure N. A layer of 38% zeolite placed on the surface of the manure reduced NH3 losses by 44%, whereas 33% coir placed on the surface of the manure reduced NH3 losses by 49%. The 20% alum treatment reduced NH3 losses by 28%. Composting poultry manure with zeolites, coir, and alum produced composts with high NH+4 concentrations ranging from 17 to 53% of total N. The addition of 20% CaCl2 to poultry manure decreased NH3 volatilization but did not result in increased NH+4 or NO−3 concentrations. The 38% zeolite Z1 and 33% coir‐treated composts had total N concentrations of 17 and 31 g kg−1, respectively. The zeolite and coir amendments were proposed to be the most suitable for reducing NH3 losses during composting of poultry manure.
Temporal Variations in Greenhouse Gas Emissions at a Midlatitude Landfill
Authors: Bogner J. E. , Spokas K. A. , Burton E. A.
Published: July 2010

A field study encompassing a parallel time series of CH4, N2O, and CO2 emissions measurements was completed by using static enclosure techniques at a midlatitude landfill (northeastern Illinois) during the period of July through December 1995. The site had a pumped gas recovery system and thus a high level of engineered gas control. No net CH4 emissions to the atmosphere were measured during this study; rather, the landfill cover soils were functioning as a sink for atmospheric CH4. The net measured emissions of CO2 (dark respiration) and N2O were in ranges characteristic of natural soils and were dependent on similar controls, including temperature, moisture, and aeration status. A comparison of proximal (near gas recovery well) and distal (between wells) emissions with soil gas profiles permitted development of a conceptual biogeochemical model for gas transport and reaction through the landfill cover. This model includes a modified reduction sequence where the major zones (from ground surface downward) were a near‐surface zone of optimum CH4 oxidation; a zone of optimum CO2 production (predominantly from root zone respiration); a zone of optimum N2O production; and a deep zone dominated by transport of landfill gas (CH4 and CO2) from methanogenic production zones in the underlying refuse.
Phytoaccumulation of Trace Elements by Wetland Plants: II. Water Hyacinth
Authors: Zhu Y. L. , Zayed A. M. , Qian J‐H. , de Souza M. , Terry N.
Published: July 2010

Wetland plants are being used successfully for the phytoremediation of trace elements in natural and constructed wetlands. This study demonstrates the potential of water hyacinth (Eichhornia crassipes), an aquatic floating plant, for the phytoremediation of six trace elements. The ability of water hyacinth to take up and translocate six trace elements—As(V), Cd(II), Cr(VI), Cu(II), Ni(II), and Se(VI)—was studied under controlled conditions. Water hyacinth accumulated Cd and Cr best, Se and Cu at moderate levels, and was a poor accumulator of As and Ni. The highest levels of Cd found in shoots and roots were 371 and 6103 mg kg−1 dry wt., respectively, and those of Cr were 119 and 3951 mg kg−1 dry wt., respectively. Cadmium, Cr, Cu, Ni, and As were more highly accumulated in roots than in shoots. In contrast, Se was accumulated more in shoots than in roots at most external concentrations. Water hyacinth had high trace element bioconcentration factors when supplied with low external concentrations of all six elements, particularly Cd (highest BCF = 2150), Cr (1823), and Cu (595). Therefore, water hyacinth will be very efficient at phytoextracting trace elements from wastewater containing low concentrations of these elements. We conclude that water hyacinth is a promising candidate for phytoremediation of wastewater polluted with Cd, Cr, Cu, and Se.
Automated Sequential Sampler for Collection of Highly Volatile Atmospheric Contaminants
Authors: Wang D. , Ernst F. F. , Yates S. R.
Published: July 2010

Rapid and accurate measurement of atmospheric concentrations of highly volatile organic compounds is important in obtaining reliable information for the assessment of environmental pollution or the volatilization mechanisms of the chemicals. Nonmechanized sample collection requires intensive labor and effort, and may cause large random or systematic errors. An automated solenoid switching system was developed to assist in obtaining precise environmental concentrations of highly volatile organic compounds. The design, construction, and operation are described in the paper for potential application in similar studies. Using this sampling system, two experiments were conducted to determine atmospheric volatilization flux density of three highly volatile and reactive organic compounds (methyl bromide, 1,3‐dichloropropene, and propargyl bromide). The automated solenoid switching system significantly reduced the requirements for labor and time. Results from the two experiments indicate that reliable sample collection was achieved. The automated sampling system was also relatively inexpensive and can be easily modified to accommodate a variety of sources, sampling intervals, and multiple number of solenoid valves.
Uncertainty Assessment in Modelling Soil Acidification at the European Scale: A Case Study
Authors: Kros J. , Pebesma E. J. , Reinds G. J. , Finke P. A.
Published: July 2010

When modelling soil acidification at the European scale, it is inevitable that both model and data have varying degrees of associated uncertainty. The present study attempted to quantify the uncertainty in long‐term forecasts of soil solution concentrations of Al3+ and NO−3 concentrations resulting from the uncertainty in small resolution European‐scale maps and input data, using the Netherlands as a case study. Large‐scale forecasts were made with a relatively simple dynamic process‐oriented model, SMART2. Model outputs were considered as block median concentrations and the block areal fractions in which concentrations exceeded a critical level. Sources of uncertainty considered included (i) uncertainty in soil and vegetation maps (categorical data), and (ii) uncertainty in soil and vegetation‐related parameters (continuous data). The uncertainty in model outputs was quantified by an efficient two‐step Monte Carlo simulation approach, which takes spatial correlation into account. The uncertainty in the input data at the European scale led to major uncertainties in the predicted Al3+ concentration. Uncertainties in the areas where the Al3+ concentration exceeded the maximum allowable concentration were much smaller. The uncertainties in soil‐related parameters contributed most to the uncertainty in the A3+ concentration, whereas the uncertainty contributed by the soil and vegetation maps was negligible. For the NO−3 concentration, however, the uncertainty originated mainly from the soil and vegetation maps. Evaluation of the different error sources is of great practical significance, as it identifies which sources need further improvement. The present study shows that the uncertainty contribution of the different error sources depends greatly on the model output considered.
Stochastic Simulation of Field‐Scale Pesticide Transport Using Opus and GLEAMS
Authors: Zacharias S. , Heatwole C. D. , Persaud N. , Bruggeman A. C. , Kumar D. , Smith C. N.
Published: July 2010

Incorporating variability in soil and chemical properties into root zone leaching models should provide a better representation of pollutant distribution in natural field conditions. Our objective was to determine if a more mechanistic rate‐based model (Opus) would predict soil water and pesticide mass in the soil profile more accurately than a capacity‐based model (GLEAMS) when spatial variability and uncertainly in parameters are considered. Predictions of spatial variations of soil water content and movement of aldicarb [2‐methyl‐2‐(methylthio)‐propionaldehyde O‐(methylcarbamoyl) oxime] and metolachlor [2‐chloro‐N‐(2‐methoxy‐1‐methylethyl) acetamide] in the root zone were compared using 3 yr of observed data from a 3.9‐ha agricultural field in southwest Georgia. Spatial variability of soil physical properties, pesticide properties, and pesticide application were described using probability distributions fitted to measured field data, after removing spatial trends that were physically meaningful. There were significant differences in mean soil water content predicted by the two models, although variations around the mean were comparable. Pesticide mass predictions were different on most post‐application dates in both mean and spatial variation. The less rigorous GLEAMS predicted mean depth‐averaged soil water content and pesticide mass in the 1.2‐m profile at least as good as the more mechanistic Opus, although it did not simulate depth distributions of water or pesticide mass as well as Opus. GLEAMS simulated spatial variations of depth‐averaged soil water content and pesticide mass in the field with reasonable accuracy while employing fewer parameters that exhibit lower spatial variability.
Estimates of Soil Nitrate Distributions Using Cokriging with Pseudo‐Crossvariograms
Authors: Zhang Renduo , Shouse Pete , Yates Scott
Published: July 2010

Nitrate (NO−3) is one of the major nonpoint source pollutants in the vadose zone. In this study, NO−3 distributions were estimated in an 800 by 800 by 1.8 m soil volume using kriging and cokriging with nonsymmetric pseudo‐crossvariograms. Cokriging with pseudo‐crossvariograms maximized the use of available information at different soil depths. Cokriging allowed easily obtained information at shallow layers to be used to improve soil chemical estimations at deeper layers. Compared with kriging, cokriging significantly reduced the mean squared errors (MSEs) and mean kriging variances (MKVs) of NO−3 estimations in the soil. For the same estimation accuracy of kriging, cokriging with pseudo‐crossvariograms used less than half the data; thus potentially it could reduce more than half the sampling cost than kriging estimation. Cokriging with pseudo‐crossvariograms was shown to be a precise and an economic way for determining nonpoint source pollutant distributions in large fields.
Evaluation of a GIS‐Linked Model of Salt Loading to Groundwater
Authors: Corwin D. L. , Carrillo M. L. K. , Vaughan P. J. , Rhoades J. D. , Cone D. G.
Published: July 2010

The ability to assess through prognostication the impact of nonpoint source (NPS) pollutant loads to groundwater, such as salt loading, is a key element in agriculture's sustainability by mitigating deleterious environmental impacts before they occur. The modeling of NPS pollutants in the vadose zone is well suited to the integration of a geographic information system (GIS) because of the spatial nature of NPS pollutants. The GIS‐linked, functional model TETrans was evaluated for its ability to predict salt loading to groundwater in a 2396 ha study area of the Broadview Water District located on the westside of central California's San Joaquin Valley. Model input data were obtained from spatially‐referenced measurements as opposed to previous NPS pollution modeling effort's reliance upon generalized information from existing spatial databases (e.g., soil surveys) and transfer functions. The simulated temporal and spatial changes in the loading of salts to drainage waters for the study period 1991–1996 were compared to measured data. A comparison of the predicted and measured cumulative salt loads in drainage waters for individual drainage sumps showed acceptable agreement for management applications. An evaluation of the results indicated the practicality and utility of applying a one‐dimensional, GIS‐linked model of solute transport in the vadose zone to predict and visually display salt loading over thousands of hectares. The display maps provide a visual tool for assessing the potential impact of salinity upon groundwater, thereby providing information to make management decisions for the purpose of minimizing environmental impacts without compromising future agricultural productivity.
Hydrologic Response: Kaho'olawe, Hawaii
Authors: Wahlstrom Erik , Loague Keith , Kyriakidis Phaedon C.
Published: July 2010

Kaho'olawe, the eighth largest island in the Hawaiian chain, has experienced major surface erosion during the last century due to overgrazing and military activity. In this paper we report the results from a series of physically‐based numerical simulations of hydrologic response, to large rainfall events, that were performed for Kaho'olawe. An event‐based rainfall‐runoff and erosion model (i.e., KINEROS) was applied, in a geographic information system (GIS) framework, to make quantitative and distributed estimates of infiltration, Horton overland flow generation, and erosion. A digital elevation model (DEM) was employed to delineate individual catchments across the island, and define areas of uniform slope within each catchment. A Landsat MSS scene of Kaho'olawe was used to classify the island into three distinct landcover categories via the normalized difference vegetation index (NDVI). The landcover categories were then used to further approximate the spatial pattern of near‐surface soil hydraulic properties across the island. Distributed estimates of saturated hydraulic conductivity and sorptivity were obtained by ordinary kriging of 135 field measurements from the island. Sensitivity analysis was performed to characterize what impact the uncertainty in soil‐hydraulic property and rainfall data had on simulated runoff. Horton overland flow and the related transport limited erosion were shown to be highly variable. The introduction of vegetation to denuded areas on Kaho'olawe was found to significantly reduce erosion.
A Flow‐Through Reactor with an Infinite Sink for Monitoring Desorption Processes
Authors: Freese Dirk , Weidler Peter G. , Grolimund Daniel , Sticher Hans
Published: July 2010

The assessment of elemental release processes in soils are of large interest in soil research. A technique is presented where the advantages of a flow‐through reactor are combined with a specific infinite sink. Between the two reactors an electrolyte solution (pH 6) acting as a transport carrier was circulated continuously in a closed‐loop setup. To demonstrate the capability of the new technique, phosphate desorption kinetics from different synthetic Fe and Mn hydroxides coated on silica sand were studied. The relative amount of P desorbed increased in the order ferrihydrite (10% of the initially sorbed P) < goethite (20%) << hematite (65%) < Mn dioxide (80%). We suggest that this technique can also be adapted to other issues, for example, desorption of other anions and cations from solid phases (soils and sediments) because the composition of the infinite sink is variable.
Evaluation of Flow and Solute Transport Parameters for Heap Leach Recovery Materials
Authors: Decker David L. , Tyler Scott W.
Published: July 2010

Mining low‐grade precious metals deposits often involves the bulk processing of ore by leaching with cyanide. Once the precious metals concentration in the leachate fluid drops to an economic cutoff point, processing ceases and the mine is required to meet drinking water standards for the latent leachate fluid that continues to drain from the heap. A common closure method is to rinse the heap with relatively clean water until the those requirements are met. However, it has been observed that concentrations of constituents, cyanide in particular, remain elevated at rinse times that exceed those times predicted with a simple advective‐dispersive type of transport model. To quantify the flow and transport behavior of spent heaps, the hydraulic and solute transport characteristics of several heap‐leach materials from northern Nevada have been determined. Data from the U.S. Bureau of Mines laboratory column tracer tests and new data collected from a series of tracer experiments with sodium Br− on heap material collected from the a large‐scale heap in the Cariin Trend, Elko County, Nevada, are presented. A 6‐m scale column incorporating time domain reflectometry was used to investigate the rinsing characteristics of spent heap‐leach material. The breakthrough curve data from these experiments are analyzed using the traditional advection‐dispersion equation and a dual‐porosity model. The dual‐porosity model provided significantly improved fits to the observed data compared with the advection‐dispersion model. Data from the experimental results are used to show optimal rinsing strategies can be developed when heap hydraulic properties are considered.
Leaching Behavior of Chlorinated Hydrocarbon Soil Fumigants in Repacked Soil Columns
Authors: Zebarth B. J. , Szeto S. Y.
Published: July 2010

The leaching behavior of Telone (active ingredients 1,3‐dichloropropene and 1,2‐dichloropropane) and Telone II (active ingredient 1,3‐dichloropropene) and the trace chlorinated hydrocarbon impurities in the fumigant formulations including 1,2,2‐trichloropropane; 1,2,3‐trichloropropane; 2,3‐dichloropropene; and 1,3‐dichloropropane, were studied using 75 cm long repacked soil columns in two experiments. In Exp. 1, soil columns received Telone, Telone II, or no soil fumigant. In Exp. 2, Telone II was applied to soil columns containing four soils: surface or subsurface samples from coarse‐ and medium‐textured soils. The concentrations of the chlorinated hydrocarbon compounds were measured in the soil and leachate. The concentrations of 3‐chloroallyl alcohol and 3‐chloroacrylic acid, breakdown products of 1,3‐dichloropropene, were also measured in leachate after Telone application. 1,3‐Dichloropropene, 3‐chloroallyl alcohol, and 3‐chloroacrylic acid degraded rapidly, and exhibited minimal adsorption to the soil. The remaining compounds were persistent in soil. Recovery of the applied compounds was lower in the surface than in the subsurface soils, particularly in the medium‐textured soil, likely due to greater biological activity in the surface soils. The risk of loss of these compounds from the root zone was minimal for 1,3‐dichloropropene, and lower with use of Telone II than of Telone. 1,2,2‐Trichloropropane was identified as the compound in Telone II most likely to result in groundwater contamination. Significant recovery of the chlorinated hydrocarbon compounds from the control treatment, using soil that had received prior fumigant applications, suggests that these compounds may be released from soil well after the time of fumigant application.
Subsurface Drainage Loss of Particles and Phosphorus from Field Plot Experiments and a Tile‐Drained Catchment
Authors: Laubel Anker , Jacobsen Ole H. , Kronvang Brian , Grant Ruth , Andersen Hans E.
Published: July 2010

Movement of particles by water through the soil can be a significant pathway for P transport to surface waters in certain soil types. Our objective was to describe and quantify particulate matter (PM), particulate phosphorus (PP) and dissolved phosphorus (DP) transport tile drains during controlled plot experiments. The results were compared to corresponding studies of natural storm events in the tile‐drained catchment as a whole. Six rain simulations (irrigation 15.3–37 mm) were carried out at two 25 m2 plots on a loamy soil. Tracer chloride concentration in the drainage water peaked within 1 h of the onset of irrigation, thus indicating rapid macropore flow to the drains. PM, PP, and DP concentrations were highest in the initial drainage flow: 63 to 334 mg PM L−1, 0.177 to 0.876 mg PP L−1, and 0.042 to 0.103 mg DP L−1, respectively. Particulate matter and PP loss rates measured for the rapid drainage flow response were in the same range in the plot experiments as for nine precipitation events in the tile‐drained catchment (13.3 ha): 171 to 630 g PM ha−1 mm−1 vs. 141 to 892 g PM ha−1 mm−1, and 0.57 to 1.75 g PP ha−1 mm−1 vs. 0.71 to 5.92 g PP ha−1 mm−1, respectively. Tracer analysis using 137Cs revealed that the PM in the drainage water was derived from the topsoil.
Temporal and Spatial Patterns of Nitrate in a Claypan Soil
Authors: Ghidey F. , Alberts E. E.
Published: July 2010

The temporal and spatial patterns of NO3‐N were studied on a 35‐ha field located in the claypan soil region of north‐central Missouri. Soil samples were collected from the 0‐ to 5‐, 5‐ to 10‐, and 10‐ to 15‐cm depths and were analyzed for NO3‐N concentrations. Surface water samples from the field were collected for NO3‐N and NH4‐N analysis during each surface runoff event. Groundwater samples were also taken from the field wells four times a year for 5 yr and analyzed for NO3‐N concentrations. The effects of topography, depth to claypan, soil pH, organic matter (OM) content, cation exchange capacity (CEC), and soil water content on the spatial distribution of NO3‐N concentration were also evaluated. Nitrate‐N concentration in the 0‐ to 5‐cm soil depth increased in the first few weeks following application, then decreased rapidly and was very low at harvest. During the study period, nitrate movement below the layer of fertilizer application was very low, and <5% of the total N applied in the soil was lost to surface runoff. Nitrate‐N concentration in groundwater samples decreased by an average of 0.40 mg L−1 yr−1 from 1992 to 1996. The semivariograms did not exhibit strong spatial dependency except for the samples collected 1 and 4 wk after fertilizer applications in 1993 and 1995, respectively. Nitrate‐N concentration was poorly correlated to soil water content and depth to claypan and relatively strongly correlated to elevation and soil pH.
Leaching of Clopyralid and Metamitron under Conventional and Reduced Tillage Systems
Authors: Cox L. , Calderón M. J. , Hermosín M. C. , Cornejo J.
Published: July 2010

The influence of conventional tillage (CT) and reduced tillage (RT) on leaching of clopyralid (3,6‐dichloropyridine‐2‐carboxylic acid) and metamitron (4‐amino‐4,5‐dihydro‐3‐methyl‐6‐phenyl‐1,2,4‐triazin‐5‐one) was monitored in a laboratory experiment with undisturbed soil columns from two plots where CT or RT practices have been used. Herbicides were applied at the rate of 5 kg ha−1 to duplicate water‐saturated columns that were leached with 600, 1200, or 1800 mL or 4000 mL of water. Clopyralid leaches more rapidly than metamitron due to its lower sorption. Higher amounts of clopyralid were detected in leachates from RT columns than in leachates from CT columns. Breakthrough of clopyralid occurred earlier in RT columns due to preferential flow, although the total amounts leached (78%) were lower than in CT columns (94%). Residual clopyralid in soil was only slightly lower in RT than in CT. Metamitron rendered similar BTCs in RT and CT although the total recovery in leachates were higher in CT columns (10%) than in RT columns (5%). Metamitron residues in soil were much lower in RT than in CT columns. Additional experiments with handpacked soil columns showed no differences in RT and CT for clopyralid, but higher leaching of metamitron in CT (16%) than in RT (8%). The lower recoveries (soil residue and leachates) observed for both herbicides under RT has been attributed to more rapid degradation in this system. These differences were much more pronounced for metamitron due to higher sorption and degradability in soil.
Methane Emission and Uptake from Soils as Influenced by Excreta Deposition from Grazing Animals
Authors: Yamulki S. , Jarvis S. C. , Owen P.
Published: July 2010

There have been only a few recent field‐based measurements to estimate the impact of excreta from grazing animals on methane (CH4) exchange. We report measurements of CH4 exchange from cattle dung and urine deposited in a simulated seasonal grazing pattern. Dung and urine samples were deposited on six separate experimental plots at different times of the year to simulate different stages of normal grazing under UK conditions to study the effects of environmental factors on CH4 exchange rates. During all the experiments, dung pats were the main emitter of CH4 with an estimated mean daily rate of 0.72 (range 0.21 to1.46) g CH4‐C per cow. Both net emission and consumption of CH4 from urine patches, however, were observed during the different experiments with a negligible mean daily emission of 0.02 (range −0.05 to 0.15) g CH4‐C per cow. Significant variations were observed between the experiments, despite the similarity of application rates and the composition of the excreta. These variations were mainly due to climatic differences when excreta were deposited: ambient temperature and rainfall were the most important factors. The estimated total annual emission of CH4 from cattle excreta deposition during the grazing season in the UK ranged between 0.42 and 3.26 (mean = 1.57) kt CH4‐C. Our work confirms other studies that suggest that excreta patches are insignificant sources of CH4 compared to the rumens of grazing cattle, and that climatic factors have a significant impact on CH4 emissions.
Nitrogen Recovery from Heat‐Dried and Dewatered Biosolids Applied to Forage Grasses
Authors: Cogger C. G. , Sullivan D. M. , Bary A. I. , Fransen S. C.
Published: July 2010

Biosolids are stabilized solids from municipal wastewater treatment that meet federal criteria for land application. Limited information exists on N availability from biosolids treated to meet Class A standards for pathogen reduction. We conducted a 2‐yr field study at two locations in western Washington: (i) to evaluate N recovery from Class A biosolids applied to two cool‐season perennial grasses, and (ii) to make practical recommendations for biosolids application rates for intensive production of these grasses. We surface‐applied two types of Class A biosolids (heat‐dried and thermophilically digested‐dewatered) at three rates to a well‐drained soil planted to tall fescue (Festuca arundinacea Schreb.) and to a poorly‐drained soil planted to perennial ryegrass (Lolium perenne L.). Each location also had N fertilizer (34‐0‐0) and zero‐N control treatments. Grass was harvested at 30 to 50 d intervals during the growing season. The two types of biosolids were similar in their ability to supply N to the grasses. At the well‐drained site, application of 1100 to 1250 kg ha−1 of biosolids N over 2 yr produced similar grass yield and apparent N recovery as 540 kg ha−1 ammonium (NH4) nitrate (NO3)‐N. At the poorly‐drained site, application of 750 to 830 kg ha−1 biosolids N over 2 yr produced similar yield and apparent N recovery as 340 kg ha−1 NH4 NO3‐N. Residual soil NO3 in the fall was low at both locations and was not affected by the biosolids treatments. Comparison with other literature suggests that these materials are as effective as liquid biosolids at supplying N to forage grasses.
Use of Plaque Assay to Detect Enteric Viruses in a Rural Watershed
Authors: Brenner Fred J. , Brenner Elaine K. , Schwartz Todd E.
Published: July 2010

Water samples were collected from four locations within the Munnell Run Watershed in Mercer County, Pennsylvania, and analyzed for fecal coliforms by MPN and enteric phages by plaque assay using Salmonella typhimurium WG 49 and Bacteroides fragilis HSP 40 as hosts. Fecal coliform concentrations and the number of phages varied seasonally (P < 0.001), as well as among the different sampling stations (P < 0.001). At all sampling stations positive for phages, S. typhimurium WG 49 PFUs outnumbered B. fragilis HSP 40 PFUs. Phages also were isolated from a septic discharge pipe and a wetland receiving septic drainage, but not from three avian species, 12 mammalian species, two streams without human wastes or from natural wetland, indicating that these viruses were of human origin. MPNs of fecal coliforms and S. typhimurium and B. fragilis PFUs were correlated with stream temperature (P < 0.001) and rainfall (P < 0.01). Only fecal coliforms and S. typhimurium WG 49 phages were correlated with suspended solids concentrations (P < 0.01). Likewise, there was a significant interaction among these parameters and MPNs of fecal coliform and HSP 40 and WG 49 PFUs (P < 0.001). The presence of host specific phages indicate the existence of septic discharges in the watershed, but both fecal coliforms and enteric viruses persist in stream systems, especially during the summer months.
Tillage Effects on Soil Nitrogen and Plant Biomass in a Corn‐Alfalfa Rotation
Authors: Rasse Daniel P. , Smucker Alvin J. M.
Published: July 2010

Alfalfa (Medicago sativa L.) stands have been reported to either decrease or increase nitrate (NO3) leaching, depending on tillage management. The fate of alfalfa‐generated N and its interaction with N fertilization in a subsequent corn (Zea mays L.) crop remains uncertain. Alfalfa contributions to corn yields and soil mineral N pools were studied under conventional tillage (CT) and no‐tillage (NT) systems over a 3‐yr corn—alfalfa—corn sequence. The field experiment compared CT vs. NT managements in fertilized and nonfertilized Kalamazoo loam soils (Typic Hapludalf). Four of the nonfertilized plots were equipped with undisturbed monolith lysimeters to monitor NO3 leaching. Living alfalfa stands lost 6 kg N ha−1 to deep leaching over a 1‐yr period, which is much less than the 20 kg NO3‐N ha−1 yr−1 lost by nonfertilized corn following corn. Within the first 6 mo following the spray‐killing of the stand, alfalfa plant tissue decomposition contributed to soil mineral N pools up to 115 kg N ha−1. During a dry year, all corn N requirements were met by plant tissue decomposition of alfalfa and soil organic matter mineralization, while applied N fertilizer accumulated in the soil profile and was highly susceptible to spring leaching. Similar quantities of N were lost to deep leaching from CT and NT systems during corn production, as higher drainage rates in NT systems were compensated by lower NO3‐N concentration of the leachates.
Longleaf Pine Photosynthetic Response to Soil Resource Availability and Elevated Atmospheric Carbon Dioxide
Authors: Runion G. B. , Mitchell R. J. , Green T. H. , Prior S. A. , Rogers H. H. , Gjerstad D. H.
Published: July 2010

Gas exchange responses during a drought cycle were studied in longleaf pine (Pinus palustris Mill.) seedlings after prolonged exposure to varying levels of atmospheric CO2 (≈365 or ≈730 µmol CO2 mol−1), soil N (40 or 400 kg N ha−1 yr−1), and water (“adequate” and “stressed”). Elevated atmospheric CO2 concentration increased photosynthesis, tended to decrease stomatal conductance, and increased water‐use efficiency (WUE). Although soil resource availability influenced gas exchange measurements, it generally did not affect the magnitude or direction of the response to CO2 concentration. However, significant interactions among treatment variables were observed for plant xylem pressure potential. In seedlings grown with high N, a positive growth response to elevated atmospheric CO2 increased whole‐plant water use resulting in more severe plant water stress, despite increased leaf‐level WUE; however, under low N conditions the lack of a growth response to elevated CO2 reduced whole‐plant water use, decreased water stress severity, and increased WUE. Photosynthetic response to CO2 was greatest in the high N treatment at the beginning of the drought cycle, but diminished as water stress increased; however, plants grown with low N showed greater photosynthetic responses to CO2 later in the drought cycle. Therefore, plant gas exchange rates interact with growth response in determining the severity of water stress under drought and, thus, the ability of elevated atmospheric CO2 to ameliorate the effects of drought and allow plants to maintain increased rates of photosynthesis may be influenced by the availability of other resources, such as N and water.
A Multi‐Year Study of Four Herbicides in Air and Precipitation from a Small Prairie Watershed
Authors: Rawn Dorothea F. K. , Halldorson Thor H. J. , Lawson B. D. , Muir Derek C. G.
Published: July 2010

Temporal trends of three phenoxyacid herbicides: 2,4‐D, dichlorprop and MCPA and the phenolic herbicide: bromoxynil, were determined in ambient air and precipitation over a 4‐yr period within a well‐defined watershed in southern Manitoba. Air concentrations ranged from below detection limits to 3.5, 1.0, 13, and 2.0 ng/m3, for 2,4‐D; dichlorprop; MCPA; and bromoxynil, respectively. The herbicides under investigation were four of the highest use herbicides in the South Tobacco Creek Watershed and were present in both air and precipitation samples at maximum concentrations during periods of local use. Concentration patterns for each herbicide in precipitation were similar each year of the study. Of the four herbicides, precipitation fluxes were greatest for MCPA in the watershed and the surrounding region. Although bromoxynil and dichlorprop were less widely used than 2,4‐D, bromoxynil precipitation fluxes exceeded those of 2,4‐D in 1993 and 1994, and dichlorprop precipitation fluxes were greater than 2,4‐D in 1994. Elevated levels of these herbicides in creek water samples were observed during periods of high concentration in both atmospheric compartments, despite the lack of surface runoff events within the watershed over that period.
Agricultural Pesticides in the Patuxent River, a Tributary of the Chesapeake Bay
Authors: Harman‐Fetcho J. A. , McConnell L. L. , Baker J. E.
Published: July 2010

The Chesapeake Bay estuarine drainage area receives the highest pesticide application of any coastal area in the USA, however, large gaps exist in information on pesticide residues entering Chesapeake Bay tributaries. Twelve pesticides, one pesticide degradation product, and one formulation by‐product were measured in the surface waters of the Patuxent River during spring/summer 1995. Pesticide concentrations were compared with river flow and estimated use patterns in the watershed. Atrazine, 6‐amino‐2‐chloro‐4‐isopropylamino‐s‐triazine (CIAT), simazine, metolachlor, and chlorpyrifos were consistently detected with maximum concentrations of 3000, 800, 2700, 70, and 190 ng/L, respectively. Concentrations were highest in the upper watershed, an area where 70% of pesticide usage occurs, and decreased with distance down the river. While tidal dilution is an important removal mechanism, degradation appears to be the main factor leading to decreases in atrazine concentrations. Atrazine levels observed at the mouth of the river correlated more strongly with high river flow events compared with the other analytes. This may be due to a local source of atrazine in the lower Patuxent River. Despite similar use rates in the watershed, metolachlor concentrations were 25 to 40 times lower than atrazine. Overall, triazine herbicides appeared to move quickly into the river and persisted longer in surface waters compared with the acetanilide herbicides. Since land use and agricultural crop patterns in the Patuxent watershed are similar to other western shore Chesapeake Bay tributaries, results of this study may be used as a starting point to predict pesticide fate and transport in this region.
Copper‐Binding Ability of Dissolved Organic Matter Derived from Anaerobically Digested Biosolids
Authors: Han Nizhou , Thompson Michael L.
Published: July 2010

The fate of metals in soils where soluble organic compounds are present may be strongly influenced by the degree to which they are complexed by organic ligands. We undertook this study to determine the combined effect of molecular weight (MW) and hydrophobicity on the Cu‐binding ability of dissolved organic compounds in biosolids (i.e., sewage sludge). Dissolved organic matter (DOM) from anaerobically digested sewage biosolids was fractionated by using a combination of MW fractionation and XAD‐8 resin chromatography (to separate the dissolved organic compounds according to hydrophilic and hydrophobic characteristics). The Cu‐binding abilities of the DOM fractions were obtained by using a Cu2+‐ion‐selective electrode (Cu‐ISE) technique. The Cu‐binding ability of fractionated DOM decreased significantly with increasing molecular weight, indicating that low‐MW DOM had more metal‐binding sites than high‐MW DOM. Within each MW fraction, the hydrophilic and the hydrophobic components also exhibited differences in Cu‐binding ability. For the DOM with MW 500–3500 Da, the hydrophilic fraction showed a greater Cu‐binding capacity than did the hydrophobic fraction, whereas the hydrophobic acid components were most important in binding Cu for DOM with MW > 3500 Da. The maximum Cu‐binding capacities of different biosolids‐derived DOM fractions, estimated by employing a Langmuir model, ranged from 1.85 to 14.3 mmol Cu mol−1 dissolved organic C (DOC), which is the same order of magnitude as similar measurements of DOM from other sources.
Validation of EPIC for Two Watersheds in Southwest Iowa
Authors: Chung S. W. , Gassman P. W. , Kramer L. A. , Williams J. R. , Gu R.
Published: July 2010

The Erosion Productivity Impact Calculator (EPIC) model was validated using long‐term data collected for two southwest Iowa watersheds in the Deep Loess Soil Region, which have been cropped in continuous corn (Zea mays L.) under two different tillage systems (conventional tillage vs. ridge‐till). The annual hydrologic balance was calibrated for both watersheds during 1988 to 1994 by adjusting the runoff curve numbers and residue effects on soil evaporation. Model validation was performed for 1976 to 1987, using both summary statistics (means or medians) and parametric and nonparametric statistical tests. The errors between the 12‐yr predicted and observed means or medians were <10% for nearly all of the hydrologic and environmental indicators, with the major exception of a nearly 44% overprediction of the N surface runoff loss for Watershed 2. The predicted N leaching rates, N losses in surface runoff, and sediment loss for the two watersheds clearly showed that EPIC was able to simulate the long‐term impacts of tillage and residue cover on these processes. However, the results also revealed weaknesses in the model's ability to replicate year‐to‐year variability, with r2 values generally <50% and relatively weak goodness‐of‐fit statistics for some processes. This was due in part to simulating the watersheds in a homogeneous manner, which ignored complexities such as slope variation. Overall, the results show that EPIC was able to replicate the long‐term relative differences between the two tillage systems and that the model is a useful tool for simulating different tillage systems in the region.
Predicting Water and Chloride Transport in Drained Soils Derived from Glacial Till
Authors: Vinten A. J. A.
Published: July 2010

Field‐scale predictions of nitrate (NO3) leaching from farmland are needed to enable zones vulnerable to ground or surface water pollution with NO3 to be identified. Use of simple water, solute transport, and N dynamics models is one way of making these predictions. In this paper, linked water and solute transport models (WATBAL/TRANSOL) are calibrated for two important arable soil types in Scotland: a clay loam (aeric haplaquept) and a sandy loam (aquic eutrochrept). Error in prediction of water and solute transport is evaluated using data from two drained plot experiments. WATBAL predicted annual deep percolation of 25 and 44% of the measured drainage flux at the clay loam and sandy loam sites, respectively. The RMS errors in prediction of annual drainflow were 14 and 13% at the clay loam and sandy loam sites, respectively. Prediction of the onset of autumn drainflow over 3 to 5 yr was good for the clay loam soil, but not the sandy loam soil. Chloride leaching was underpredicted by about 22% at the sandy loam site and by 15% at the clay loam site in the first year after chloride tracer application. This indicates the likely extent of under prediction of solute leaching to drains when these models are linked to other models, such as simulations of N dynamics.
Environmental Consequences of Apple Waste Deposition on Soil
Authors: de Cockborne A. M. , Vallès V. , Bruckler L. , Sevenier G. , Cabibel B. , Bertuzzi P. , Bouisson V.
Published: July 2010

In the Provence Alpes Côte d'Azur region (France), overproduction of apple (Malus domestica Borkh.) can result in a significant surplus (0–230 000 Mg per year between 1986 and 1995) which has to be used or destroyed. Among the possibilities for disposing of overproduction, land application is flexible and inexpensive. A field study was undertaken to identify the environmental risks and main biogeochemical processes involved when apple waste is applied to farm land. Three experimental plots receiving 0, 500, or 1000 Mg of apple ha−1 were studied. Soil solutions were collected at three depths (0–0.3, 0.3–0.6, and 0.6–0.9 m) at different times, pH and Eh were measured, major ions, metals, and total and carbonated alkalinity were analyzed. Rapid pH and Eh decrease (from 7.0‐5.5 for the pH and from +500 to −300 mV for the redox potential) were observed. The soil became reduced, thus causing the dissolution of Mn. Nitrogen immobilization and denitrification resulting from waste application explained NO−3 depletion in the soil. The formation of organic anions complexed the metals and major cations. Finally, the oxidation of the soil during drying created conditions which polluted less, emphasizing the importance of the choice of season for land application of organic waste.
Nitrogen Availability and Leaching from Soil Amended with Municipal Solid Waste Compost
Authors: Mamo M. , Rosen C. J. , Halbach T. R.
Published: July 2010

Beneficial use of municipal solid waste compost depends on identifying a management strategy that supports crop production and protects water quality. Effects of compost and N fertilizer management strategies on corn (Zea mays L.) yield and NO−3‐N leaching were evaluated in a 3‐yr study on a Hubbard loamy sand soil (sandy, mixed, Udorthentic Haploboroll). Two composts were each applied at either 90 Mg ha−1 yr−1 from 1993 to 1995, or at 270 Mg ha−1 in one application in 1993. The compost and non‐amended plots were sidedressed annually with N fertilizer as urea at 0, 125, and 250 kg ha−1. Biochemical properties of the compost as well as compost management strongly affected crop response and fate of N. Compost increased grain yield with no significant yield response to N fertilizer with the single compost application in Year 1 and the annual compost application in Year 3. Plant N uptake increased with N fertilizer rate, except in the 270 Mg ha−1 compost treatments in Year 1. Over the 3‐yr period, NO−3‐N leaching with the 270 Mg ha−1 compost application was 1.8 times greater compared to that with the annual application. The estimated N mineralization ranged from 0 to 12% and 3 to 6% in the annual and single compost addition, respectively. Under the conditions of this study, annual compost application with reduced supplemental N fertilizer was the best management strategy to reach optimum crop yield while minimizing NO−1‐N leaching losses.