bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantity and Quality of Runoff from a Beef Cattle Feedlot in Southern Alberta
Authors: Miller Jim J. , Handerek Brian P. , Beasley Bruce W. , Olson Edith C. S. , Yanke L. Jay , Larney Francis J. , McAllister Tim A. , Olson Barry M. , Selinger L. Brent , Chanasyk David S. , Hasselback Paul 
Published: June 2010

ABSTRACTSouthern Alberta, which has a cold climate dominated by strong chinook winds, has the highest density of feedlot cattle in Canada. However, the quantity and quality of runoff from beef cattle (Bos taurus) feedlots in this unique region has not been investigated. Our objectives were to compare runoff quantity (1998–2002) with catch‐basin design criteria; determine concentrations of selected inorganic chemical parameters (1998–2000) in runoff in relation to water quality guidelines and the potential implications of irrigating adjacent cropland; and determine if total heterotrophs, total coliforms, and Escherichia coli (1998–2000) persisted in the catch‐basin water and soil. Runoff (<0.1 to 42.5 mm) for a 24‐h duration that included maximum peak discharge was less than the recommended design criteria of 90 mm based on runoff from 24 h of rainfall with a 30‐yr return period. We found that curve numbers between 52 and 96 (mode of 90) were required to match the USDA Natural Resources Conservation Service predicted runoff and actual runoff volumes. Total P posed the greatest threat to water quality guidelines, and K posed the greatest threat for exceeding crop fertilizer requirements if catch‐basin effluent was used as irrigation water. Water in the catch basin had continually high populations of E. coli throughout the study, with values ranging between log10 2 and log10 8 100 mL−1 In contrast, soil in the catch basin generally had low populations of E. coli that were <log10 2 g−1 wet wt., but at times higher populations between log10 2 and log10 6 g−1 wet wt. were also found.
A Comparison of In Situ Methods for Measuring Net Nitrogen Mineralization Rates of Organic Soil Amendments
Authors: Hanselman Travis A. , Graetz Donald A. , Obreza Thomas A. 
Published: June 2010

ABSTRACTIn situ incubation methods may help provide site‐specific estimates of N mineralization from land‐applied wastes. However, there are concerns about the reliability of the data generated by the various methods due to containment artifacts. We amended a sandy soil with either poultry manure, biosolids, or yard‐waste compost and incubated the mixtures using four in situ methods (buried bags, covered cylinders, standard resin traps, and “new” soil–resin traps) and a conventional laboratory technique in plastic bags. Each incubation device was destructively sampled at 45‐d intervals for 180 d and net N mineralization was determined by measuring the amount of inorganic N that accumulated in the soil or soil plus resin traps. Containment effects were evaluated by comparing water content of the containerized soil to a field‐reference soil column. In situ incubation methods provided reasonable estimates of short‐term (<45 d) N mineralization, but long‐term (>45 d) mineralization data were not accurate due to a variety of problems specific to each technique. Buried bags and covered cylinders did not retain mineralized N due to water movement into and out of the containers. Neither resin method captured all of the mineralized N that leached through the soil columns, but the new soil–resin trap method tracked field soil water content better than all other in situ methods evaluated. With further refinement and validation, the new soil–resin trap method may be a useful in situ incubation technique for measuring net N mineralization rates of organic soil amendments.
Denitrification Enzyme Activity of Fringe Salt Marshes in New England (USA)
Authors: Wigand Cathleen , McKinney Richard A. , Chintala Marnita M. , Charpentier Michael A. , Groffman Peter M. 
Published: June 2010

ABSTRACTCoastal salt marshes are a buffer between the uplands and adjacent coastal waters in New England (USA). With increasing N loads from developed watersheds, salt marshes could play an important role in the water quality maintenance of coastal waters. In this study we examined seasonal relationships between denitrification enzyme activity (DEA) in salt marshes of Narragansett Bay, Rhode Island, and watershed N loadings, land use, and terrestrial hydric soils. In a manipulative experiment, the effect of nutrient enrichment on DEA was examined in a saltmeadow cordgrass [Spartina patens (Aiton) Muhl.] marsh. In the high marsh, DEA significantly (p < 0.05) increased with watershed N loadings and decreased with the percent of hydric soils in a 200‐m terrestrial buffer. In the low marsh, we found no significant relationships between DEA and watershed N loadings, residential land development, or terrestrial hydric soils. In the manipulation experiment, we measured increased DEA in N‐amended treatments, but no effect in the P‐amended treatments. The positive relationships between N loading and high marsh DEA support the hypothesis that salt marshes may be important buffers between the terrestrial landscape and estuaries, preventing the movement of land‐derived N into coastal waters. The negative relationships between marsh DEA and the percent of hydric soils in the adjacent watershed illustrate the importance of natural buffers within the terrestrial landscape. Denitrification enzyme activity appears to be a useful index for comparing relative N exposure and the potential denitrification activity of coastal salt marshes.
Improvements to Measuring Water Flux in the Vadose Zone
Authors: Masarik Kevin C. , Norman John M. , Brye Kristofor R. , Baker John M. 
Published: June 2010

ABSTRACTEvaluating the impact of land use practices on ground water quality has been difficult because few techniques are capable of monitoring the quality and quantity of soil water flow below the root zone without disturbing the soil profile and affecting natural flow processes. A recently introduced method, known as equilibrium tension lysimetry, was a major improvement but it was not a true equilibrium since it still required manual intervention to maintain proper lysimeter suction. We addressed this issue by developing an automated equilibrium tension lysimeter (AETL) system that continuously matches lysimeter tension to soil‐water matric potential of the surrounding soil. The soil‐water matric potential of the bulk soil is measured with a heat‐dissipation sensor, and a small DC pump is used to apply suction to a lysimeter. The improved automated approach reported here was tested in the field for a 12‐mo period. Powered by a small 12‐V rechargeable battery, the AETLs were able to continuously match lysimeter suction to soil‐water matric potential for 2‐wk periods with minimal human attention, along with the added benefit of collecting continuous soil‐water matric potential data. We also demonstrated, in the laboratory, methods for continuous measurement of water depth in the AETL, a capability that quantifies drainage on a 10‐min interval, making it a true water‐flux meter. Equilibrium tension lysimeters have already been demonstrated to be a reliable method of measuring drainage flux, and the further improvements have created a more effective device for studying water drainage and chemical leaching through the soil matrix.
Nitrogen Cycling through Swine Production Systems
Authors: Harper Lowry A. , Sharpe Ron R. , Parkin Tim B. , De Visscher Alex , van Cleemput Oswald , Byers F. Michael 
Published: June 2010

ABSTRACTAmmonia (NH3) emissions from animal systems have become a primary concern for all of livestock production. The purpose of this research was to establish the relationship of nitrogen (N) emissions to specific components of swine production systems and to determine accurate NH3 emission factors appropriate for the regional climate, geography, and production systems. Micrometeorological instrumentation and gas sensors were placed over two lagoons in North Carolina during 1997–1999 to obtain information for determining ammonia emissions over extended periods and without interfering with the surrounding climate. Ammonia emissions varied diurnally and seasonally and were related to lagoon ammonium concentration, acidity, temperature, and wind turbulence. Conversion of significant quantities of ammonium NH4+ to dinitrogen gas (N2) were measured in all lagoons with the emission rate largely dependent on NH4+ concentration. Lagoon NH4+ conversion to N2 accounted for the largest loss component of the N entering the farm (43% as N2); however, small amounts of N2O were emitted from the lagoon (0.1%) and from field applications (0.05%) when effluent was applied nearby. In disagreement with previous and current estimates of NH3 emissions from confined animal feeding operation (CAFO) systems, and invalidating current assumptions that most or all emissions are in the form of NH3, we found much smaller NH3 emissions from animal housing (7%), lagoons (8%), and fields (2%) using independent measurements of N transformation and transport. Nitrogen input and output in the production system were evaluated, and 95% of input N was accounted for as output N from the system.
Coupled Abiotic–Biotic Mineralization of 2,4,6‐Trinitrotoluene (TNT) in Soil Slurry
Authors: Schrader Paul S. , Hess Thomas F. 
Published: June 2010

ABSTRACTThe explosive 2,4,6‐trinitrotoluene (TNT) is a contaminant of soils and ground waters worldwide. To help alleviate such environmental contamination, we investigated a coupled abiotic–biotic treatment scheme for remediating TNT‐contaminated soil in slurry solutions. Two types of soil were used (sandy and silt loam) to simulate different soils that might be found at actual sites. These soils were subsequently contaminated with 5000 mg kg−1 TNT. Mineralization of TNT was initially optimized for minimum reactant use (Fe3+ and H2O2) and maximum soil slurry percentage (percent solids) using modified Fenton reactions conducted in the absence of light followed by the addition of an uncharacterized aerobic biomass. Greater than 97% TNT degradation was observed under optimum reaction conditions for both soils. Using two optimum reactant concentrations for each soil, coupled abiotic–biotic reactions showed an increase in TNT mineralization, from 41 to 73% and 34 to 64% in the sandy soil (10 and 20% slurry, respectively, 1470 mM H2O2), and increases from 12 to 23% and 13 to 28% in the silt loam soil (5% slurry, 294 and 1470 mM H2O2, respectively). These results show promise in the use of combined abiotic–biotic treatment processes for soils contaminated with high concentrations of TNT.
Simulating Nitrogen Dynamics in Agricultural Soils Fertilized with Pig Slurry and Urea
Authors: Marchetti Rosa , Ponzoni Gilda , Spallacci Pasquale 
Published: June 2010

ABSTRACTWithin the framework of an interregional project in the Emilia Romagna region of northern Italy, the coupled MACRO–SOILN model was chosen to estimate soil protective capacity against pollutants. The aim of our study was to evaluate the model to better identify key parameters and processes that influence N losses in agricultural soils. Nitrate N content was monitored in soil under corn (Zea maysL.) fertilized with urea and/or pig slurry, in two field experiments performed on four different soils: a Fienili clay, a Barco‐like silt, a Sant'Omobono silt loam, and a La Boaria silty clay soil. Measurements were compared with model predictions. For all soils, nitrate content was underestimated on average by 24 to 88% at lower N rates; it was overestimated by 1 to 104% at higher N rates. The root mean square error (RMSE) was equal to 81.1%. Simulation of crop N uptake and soil water flow, estimation of the ammonia losses at pig slurry spreading, and N transformation parameter setting were considered as possible error sources. The calibration of crop N uptake gave rise to good model efficiency index values. The RMSE for the simulation of soil water content varied between 9.8 and 20.2%. A more accurate setting of the ammonia losses and of the feces transformation parameter values could allow the RMSE for the simulation of soil nitrate content to be reduced by no more than 10 to 15%. It is possible for the model not to include the simulation of processes that could have relevant effects on the soil N dynamics.
Influence of Nutrient Levels on Uptake and Effects of Mercury, Cadmium, and Lead in Water Spinach
Authors: Göthberg Agneta , Greger Maria , Holm Karin , Bengtsson Bengt‐Erik 
Published: June 2010

ABSTRACTIn Southeast Asia the aquatic macrophyte water spinach (Ipomoea aquatica Forsk.) is a popular vegetable that is cultivated in freshwater courses. These often serve as recipients for domestic and other sorts of wastewater that often contain a variety of pollutants, such as heavy metals. In addition, fertilizers are frequently used where water spinach is cultivated commercially for the food market. To estimate the importance of ambient nutrient concentrations for accumulation of mercury (Hg), cadmium (Cd), and lead (Pb) in water spinach, plants were exposed to nutrient solutions of different strength and with varying metal concentrations. Metal‐induced toxic effects, which might possibly affect the yield of the plants, were also studied. The lower the nutrient strength in the medium was, the higher the metal concentrations that accumulated in the different plant parts and the lower the metal concentration in the medium at which metal‐induced toxic effects occurred. Accordingly, internal metal concentrations in the plants were correlated to toxic effects. Plants exposed to metals retained a major proportion of the metals in the roots, which had a higher tolerance than shoots for high internal metal concentrations.
Effect of Cobalt Sorption on Metal Fractionation in Anaerobic Granular Sludge
Authors: Osuna M. Begoña , van Hullebusch Eric D. , Zandvoort Marcel H. , Iza Jon , Lens Piet N. L. 
Published: June 2010

ABSTRACTA sequential extraction procedure was applied to two anaerobic methanogenic sludges (Eerbeek and Nedalco) to examine the speciation of micro‐ and macronutrients in the sludges after cobalt sorption by exposing the sludge to a 1 mM Co solution for 4 d at pH 7 and 30°C. The effect of different physicochemical conditions on cobalt sorption was studied as well: effect of pH (6–8), effect of competition by a second trace element (Ni or Fe), modification of the granular matrix by glutaraldehyde or heat treatment, and EDTA (ethylenediaminetetraacetic acid) addition. Sorbed Co was found to distribute between the carbonates, organic matter + sulfides, and residual fractions. Cobalt adsorption resulted in an antagonistic interaction with other metals present in the granular matrix, evidenced by the solubilization of other trace elements (e.g., Ni, Cu, and Zn) as well as macronutrients (especially Ca and Fe). Modification of the sludge matrix by glutaraldehyde or heat treatment, or exposure to EDTA, led to serious modifications of the Co sorption capacity and strong interactions with multivalent cations (i.e., Ca2+ and Fe2+).
Transport and Fate of Nitrate in Headwater Agricultural Streams in Illinois
Authors: Royer Todd V. , Tank Jennifer L. , David Mark B. 
Published: June 2010

ABSTRACTNitrogen inputs to the Gulf of Mexico have increased during recent decades and agricultural regions in the upper Midwest, such as those in Illinois, are a major source of N to the Mississippi River. How strongly denitrification affects the transport of nitrate (NO3–N) in Illinois streams has not been directly assessed. We used the nutrient spiraling model to assess the role of in‐stream denitrification in affecting the concentration and downstream transport of NO3–N in five headwater streams in agricultural areas of east‐central Illinois. Denitrification in stream sediments was measured approximately monthly from April 2001 through January 2002. Denitrification rates tended to be high (up to 15 mg N m−2 h−1), but the concentration of NO3–N in the streams was also high (>7 mg N L−1). Uptake velocities for NO3–N (uptake rate/concentration) were lower than reported for undisturbed streams, indicating that denitrification was not an efficient N sink relative to the concentration of NO3–N in the water column. Denitrification uptake lengths (the average distance NO3–N travels before being denitrified) were long and indicated that denitrification in the streambed did not affect the transport of NO3–N. Loss rates for NO3–N in the streams were <5% d−1 except during periods of low discharge and low NO3–N concentration, which occurred only in late summer and early autumn. Annually, most NO3–N in these headwater sites appeared to be exported to downstream water bodies rather than denitrified, suggesting previous estimates of N losses through in‐stream denitrification may have been overestimated.
Sorption of Apolar Aromatic Compounds to Soil Humic Acid Particles Affected by Aluminum(III) Ion Cross‐Linking
Authors: Lu Yuefeng , Pignatello Joseph J. 
Published: June 2010

ABSTRACTSorption of hydrophobic compounds in soils often shows nonlinearity, competition, and hysteresis. Since such behaviors have been associated with organic polymers in glassy state, it has been postulated that some forms of soil humic substances are glassy. The glassy state is favored by properties that decrease the flexibility of macromolecules, such as cross‐linking, presence of unsaturated bonds, and high molecular weight. Polyvalent metal ions, which are abundant in soils, may cross‐link humic substances by coordinating to multiple functional groups on different strands. Accordingly, we prepared an Al3+–cross‐linked humic acid (Al‐HA) from the H+ form (H‐HA) of a soil humic acid by a flocculation technique that leaves Al ions bound to organic groups. Sorption of naphthalene and 1,2,4‐trichlorobenzene (TCB) on H‐HA was nonlinear, competitive, and slightly hysteretic, in agreement with previous studies showing glass transition temperatures of humic acids that lie above room temperature. Nonlinearity, competition, and hysteresis were all enhanced in Al‐HA, validating the hypothesis that metal ion cross‐linking enhances nonideal sorption. Application of a glassy polymer sorption model reveals that cross‐linking increases the affinity of solutes for the hole domain relative to the dissolution domain. The results (i) indicate that isolated, purified soil humic acid behaves like a glassy solid, (ii) indicate that metal‐ion cross‐linking creates a more rigid‐chain structure and supports a link between nonideal sorption and the glassy character of soil organic matter, and (iii) underscore the importance of metal ions on humic structure in relation to sorption of hydrophobic organic compounds.
Phosphorus Desorption Dynamics in Soil and the Link to a Dynamic Concept of Bioavailability
Authors: Koopmans G. F. , Chardon W. J. , de Willigen P. , van Riemsdijk W. H. 
Published: June 2010

ABSTRACTSoils under intensive livestock farming and heavily fertilized with animal manure may have elevated soil phosphorus (P) contents. We determined P desorption kinetics in batch experiments using soils from a pot experiment where grass was cropped on a P‐rich noncalcareous sandy soil without P addition, to lower the soil P content. A diffusion model was used to describe P desorption kinetics from a spherical aggregate. The model was calibrated with data from the batch experiments. Simulation results show that in the pot experiment, P desorption from the solid phase of the inner layers was initially far from equilibrium with the rest of the aggregate, but desorption came closer to equilibrium as the soil P content decreased further. A simple tool is presented, referred to as the dynamic bioavailability index (DBI), to determine whether kinetics of P desorption limits plant uptake. This tool is the dimensionless ratio of the modeled maximal diffusive flux from soil aggregates to solution and the plant uptake rate measured in the pot experiment. The DBI was initially much larger than one; the maximal possible P desorption rate exceeded the uptake rate, so uptake was not limited by desorption. The DBI stabilized at a value somewhat larger than one after a while, due to soil transport limitations. This decrease coincided with a large decrease of the P content in the grass to a value (far) below what is considered as optimal; the supply rate of P from soil to the root cannot meet the demand needed for optimal P uptake. The DBI could be seen as a promising onset to a new dynamic approach of bioavailability.
Potential Loss of Phosphorus from a Rice Field in Taihu Lake Basin
Authors: Zhang ZhiJian , Zhu YinMei , Guo PeiYong , Liu GuangSheng 
Published: June 2010

ABSTRACTNonpoint‐source pollution by phosphorus (P) poses a threat to waters in the Taihu Lake basin in China. The potential transfer of P in rice (Oryza sativa L.) fields through surface drainage and subsurface flow was investigated under simulated conventional irrigation–drainage management. Surface drainage events were conducted to avoid overflow across the plots after heavy rainfall and for rice harvest, at which time P losses were also investigated. This study was conducted in 2001 in a long‐term rice field experiment. The experimental plots were treated with 0, 26, or 52 kg P ha−1 as superphosphate or 26 kg P ha−1 with equal parts of P supplied as superphosphate and pig manure. Phosphorus concentrations and loads in field floodwater on plots receiving P rapidly declined in a nonlinear manner before the first drainage, three weeks after fertilizer application. The combined application of fertilizer and manure P resulted in higher P transfer potential in field floodwater than with fertilizer P alone one week after P application. Phosphorus concentrations in interflow water sampled by Teflon suction cups inserted at a depth of 150 to 200 mm gradually increased within two weeks after P application, then declined. The concentration of P in interflow water was related to soil P buildup from long‐term P application, as well as recently applied P. The 26 kg P ha−1 treatment (the conventional P rate in this region) resulted in a loss of 0.74 kg total phosphorus (TP) ha−1 and a drainage‐weighted average concentration of 0.25 mg TP L−1 from the three surface drainage events. Results indicate that avoiding overflow drainage after P input and extending the time between P application and drainage may reduce P losses from rice paddies.