bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrate Leaching from Grassed Lysimeters Treated with Ammonium Nitrate or Slow‐Release Nitrogen Fertilizer
Authors: Owens L. B. , Edwards W. M. , Van Keuren R. W. 
Published: July 2010

AbstractNitrate leaching is a potential in humid regions when crops and forages are fertilized. This study was conducted to compare NO3 leaching with two different N fertilizer formulations applied to forages. For 11 yr, ammonium nitrate (AN) was applied to a large (8.1 m2 surface area), undisturbed, monolithic lysimeter Y101B at an annual rate of 168 kg N ha−1, and methylene urea (MU), a slow‐release fertilizer, was applied to a similar lysimeter (Y101D) at the same rate. Nitrate‐N concentrations in the percolate from these 2.4 m‐deep lysimeters were measured weekly. Even though NO3‐N levels increased steadily with the AN applications, the greatest increases occurred during the eighth year of treatment and reached levels above 20 mg L−1. With the MU, NO3‐N concentrations remained relatively constant until after 8 yr of treatment, reaching concentrations of 6 mg L−1. The highest rates of annual NO3‐N transport in percolate were 42.3 and 12.1 kg ha−1 from lysimeters treated with AN and MU, respectively. (Losses from NH3 volatilization were measured at 12.0 and 44.8 kg N ha−1 for AN and MU, respectively.) Nitrate‐N transport in percolate varied seasonally with the greatest amounts being moved during the late winter‐early spring. Following 11 yr, the NO3‐N concentrations in each lysimeter declined to approximately 1 mg L−1. Based on this study with a 168 kg N ha−1 annual application rate, less NO3‐N leaching will occur when a slow‐release N fertilizer, such as MU, is applied to forages than when AN is applied.
Field‐Scale Study of Chlortoluron Movement in a Sandy Soil over Winter: I. Experiments
Authors: Zander Christine , Streck Thilo , Kumke Thomas , Altfelder Sven , Richter Jörg 
Published: July 2010

AbstractThe transport of the herbicide chlortoluron (3‐(3‐chlor‐p‐tolyl)‐1,1‐dimethylurea) was monitored in Northern Germany in a sandy soil between November 1994 and March 1995. On a 0.86‐ha grid, soil cores were taken down to a depth of 0.3 m and analyzed for total chlortoluron concentrations at 0.03‐m intervals. A bromide (Br−) transport experiment was carried out at the same site. Thirty‐three, 61, and 136 d after application, corresponding to 54, 115, and 305 mm of precipitation, chlortoluron was found almost exclusively in the upper two, four, and six layers, respectively. In these layers, coefficients of variation (CVs) varied from about 50 to >200%. At the first sampling, about 1% of applied chlortoluron was detected in the layer just above the plow‐sole. Mean travel depths of chlortoluron were distinctly more variable than those of Br−, showing no spatial correlation. The retardation factor of chlortoluron, expressing its displacement relative to that of Br−, considerably increased during the experiment, on the average from 11.5 at the first sampling to 26.3 at the third sampling. Only then, the local mean travel depths of chlortoluron showed a significant (positive) correlation with those of Br− and a significant (negative) correlation with organic C contents. Sorption kinetics of chlortoluron were investigated in laboratory sorption‐desorption (SD) experiments at 3 and 20°C. Sorption‐desorption isotherms showed pronounced hysteresis. The influence of experimental temperature was small. The collected data are intended as a basis to evaluate the ability of different modeling approaches to represent pesticide displacement at the field scale.
Dye Adsorption in a Loam Soil as Influenced by Potassium Bromide
Authors: Allaire‐Leung S. E. , Gupta S. C. , Moncrief J. F. 
Published: July 2010

AbstractFD&C Blue #1 and Rhodamine WT have been used in soils to trace preferential flow paths while bromide has been used to study flow paths of water or nonretarded chemicals. This study quantified the interactions of KBr, FD&C Blue #1, and Rhodamine WT on dye adsorption in Forman loam (fine‐loamy, mixed Udic Argiboroll) soil. The experiment involved characterization of adsorption isotherms and breakthrough curves for various mixtures of tracers at different concentrations. Batch equilibration studies showed that the adsorption of FD&C Blue #1 and Rhodamine WT on Forman loam was not influenced by the presence of each other. The adsorption of FD&C Blue #1 and Rhodamine WT, however, increased with an increase in the concentration of KBr. The slope of linear adsorption isotherm (Kd) increased from 5.0 to 15.0 cm3 g−1 for FD&C Blue #1 and from 4.2 to 5.0 cm3 g−1 for Rhodamine WT on addition of 1000 mg L−1 of KBr. In a flow‐through experiment, FD&C Blue #1 movement was twice as slow in presence of KBr than in absence of KBr. The Kd values from the flow‐through experiment were lower than those from the batch equilibration experiments. We conclude that the retardation coefficients estimated from the batch equilibration studies are not realistic for application to leaching experiments, and the presence of tracer interaction can potentially complicate the interpretation of dye flow patterns observed with the use of multiple tracer technique.
Nutrient Leaching from Corn Residues under Simulated Rainfall
Authors: Schreiber J. D. 
Published: July 2010

AbstractCrop residues left on the soil surface after harvest are effective in reducing erosion; however, when subjected to rainfall‐leaching, the residues are a significant source of soluble nutrients to agricultural runoff. Nutrient leaching from crop residues as a function of rainfall intensity, and residue loading rate, was studied in a series of laboratory experiments under controlled conditions. Using a multiple‐intensity rainfall simulator corn (Zea mays L.) stover placed on a nylon screen at an equivalent field loading rate of 10 t ha−1, was subjected to simulated rainfall at intensities of 6, 12, 25, 51, and 99 mm h−1. In another series of experiments, simulated rainfall was applied at 25 mm h−1 to four stover loading rates of 5, 7, 10, and 15 t ha−1. In both experiments, leachate was sampled as a function of time and analyzed for PO4‐P, NH4‐N, NO3‐N, and total organic carbon (TOC). Nutrient concentrations and losses were generally greater at the lower rainfall intensities and higher stover loading rates. In each study, nutrient concentrations decreased hyperbolically with either time or cumulative leachate volume. For all loading rates and rainfall intensities, nutrient amounts (kg ha−1) leached from the stover followed the order C ≫N = P; however, the amounts of N as (NH4‐N + NO3‐N) or C leached were ≤1.5% of total nutrient in residue compared with 2.8 to 6.0% of total nutrient in residue for P. Stover exposed to field conditions over time showed leaching kinetics similar to freshly collected residues.
Estimating Errors Associated with Extracting Phosphorus Using Iron Oxide and Resin Methods
Authors: Uusitalo Risto , Yli‐Halla Markku 
Published: July 2010

AbstractDissolution of particulate P from adhering soil material may cause an error in estimating bioavailable P with Fe oxide‐impregnated filter paper (FeO) strips and anion exchange resin (AER) bags. This error was assessed with two clayey soil samples and agricultural runoff waters high in suspended clay. Iron oxide strips were shaken either unprotected in soil suspension or enclosed in nylon mesh bags. Resin in bags and loose AER beads were used in the AER extractions. Sodium chloride and HCl extractions were compared in the displacement of P retained by the AER. Aluminum and Si served as index elements for the presence of soil material. Overestimation of desorbable P by 2.5 to 2.7 mg kg−1 for each strip was measured, compared with about 30 mg kg1 of FeO strip‐extractable P in the soils. Enclosing the FeO strips in nylon mesh bags reduced soil attachment by about 60%. The error due to dissolution of particulate P was negligible with the AER method. The FeO‐strip procedure was problematic in the water sample study. The highest P yield occurred when FeO strips were protected with nylon mesh, followed by unprotected FeO strips, AER(HCl), AER(NaCl), and loose AER beads. Overnight shaking with an unprotected FeO strip extracted 23 to 65% more P, and four sequential extractions 140 to 196% more P, than the AER(NaCl) method. In analysis of turbid water samples, the risk of overestimating P bioavailability was much lower with the AER(NaCl) method than with the FeO‐strip method.
Effect of Various Pollutants and Soil‐Like Constituents on Laccase from Cerrena unicolor
Authors: Filazzola M.T. , Sannino F. , Rao M. A. , Gianfreda L. 
Published: July 2010

AbstractLaccase from Cerrena unicolor catalyses the oxidation of a wide range of aromatic compounds, either xenobiotic or naturally occurring phenols, leading to the formation of polymeric products. These are characterized by their low solubility and often may form precipitates or aggregates. The oxidizing efficiency of the enzyme is strictly dependent on the number of hydroxyl groups and the position of substituents on the phenolic molecules. During the reaction with some substrates, the enzyme is inactivated, because of possible adsorption of laccase molecules on newly formed polyphenols. By contrast, the oxidation of humic precursors (i.e., resorcinol, gallic acid, and pyrogallol) does not influence greatly the residual laccase activity. The triazinic herbicides, triazine and prometryn (2,4‐bis(isopropylamino)‐6‐methylthio‐s‐triazine), are not substrates of laccase. They, however, inhibit laccase activity assayed with 2,4‐dichlorophenol (2,4‐DCP) or catechol as substrates. The reduction of substrate oxidation rates is usually accompanied by the retention of higher levels of residual enzymatic activity. These results, together with the slight recovery in laccase activity following dialysis of the assay mixture, provide further evidence that the enzyme may be incorporated into or adsorbed onto polyphenolic products, with a consequent reduction in the concentration of active forms of laccase.
Methane Emissions of Beef Cattle Grazing Tall Fescue Pastures at Three Levels of Endophyte Infestation
Authors: Pavao‐Zuckerman Mitchell A. , Waller John C. , Ingle Teri , Fribourg Henry A. 
Published: July 2010

AbstractMethane (CH4) is produced by fermentation in the rumen of cattle. Methane may play a part in global warming scenarios. Tall fescue (Festuca arundinacea Schreb.) is an important forage in the eastern United States. The toxic syndrome associated with the endophytic fungus Neotyphodium coenophialum (E+) can be mitigated with management strategies that improve forage quality of E+ tall fescue pastures and animal performance. The sulfur hexafluoride (SF6) tracer technique was used to determine the effects of tall rescue pasture management on CH4 production in 1997–1998. Two steers (Bos taurus) on two pastures each of E+ tall fescue, of endophyte free (E−) tall fescue, of E+/E−(1:1 ratio), and of E+/ladino white clover (Trifolium repens L.), and four steers and four lactating cows with nursing calves grazing either unimproved (UP) or best management practices (BMP) pastures were used to collect eructated CH4 samples. Daily CH4 emissions were about 95 to 200 g d−1 for steers and 150 to 240 g d−1 for cows. Steers grazing E+/clover pastures emitted 20% less CH4 kg−1 d−1 than steers grazing E+, E−, or E+/E− in summer. Season and animal size were the major factors affecting CH4 emissions. This first estimation of CH4 emissions from free‐roaming cattle grazing tall fescue pastures indicates that (i) improved forage management strategies have little effect on daily emissions per animal that are primarily a function of rumen size and intake, and (ii) the amount of emission per unit of animal product is reduced when improved practices are implemented.
Responses of a Nitrogen‐Saturated Forest to a Sharp Decrease in Nitrogen Input
Authors: Quist Maud E. , Näsholm Torgny , Lindeberg Johan , Johannisson Christian , Högbom Lars , Högberg Peter 
Published: July 2010

AbstractThe reversibility of induced N saturation was investigated in a 46‐yr‐old pine (Pinus sylvestris L.) forest in northern Sweden. Ammonium nitrate has been applied annually since 1971 to plots (30 by 30 m) at average dosages of 36 (N1), 72 (N2), and 108 (N3) kg N ha−1 yr−1, with or without P and K addition (background N deposition is <4 kg ha−1 yr−1). In 1990, after two decades of treatment, the largest N application (N3) was suspended, while N1 and N2 still received ammonium nitrate applications. Seven years after the last application in N3, the N availability measured as N concentration in plants [pine roots and needles and in leaves of the grass Deschampsia flexuosa (L.) Trin.] and activity of the enzyme nitrate reductase in leaves of D. flexuosa, and 15N uptake by excised pine roots, was at the same levels as in N1, although more than twice the amount of N has been applied in total to N3. The arginine concentrations in pine needles, concentrations of exchangeable mineral N in the organic layer, and the uppermost 20 cm of the mineral soil were at the same levels as in the control plots. Thus, an experimentally induced N excess was, according to these measurements, to a high degree reversed 7 yr after the last N application. However, the composition of the understory vegetation still differed markedly from the untreated control 8 yr after the last N3 application.
Denitrification from Fescue Pastures in the Southeastern USA Fertilized with Broiler Litter
Authors: Marshall S. B. , Cabrera M. L. , Braun L. C. , Wood C. W. , Mullen M. D. , Guertal E. A. 
Published: July 2010

AbstractMany aspects of the denitrification process in pasture ecosystems remain poorly investigated, especially as affected by application of animal manures. Denitrification can be, however, a major pathway of N loss from soil, decreasing efficiency of N fertilizers, as well as contributing to global warming and ozone depletion. We quantified N loss via denitrification from tall fescue (Festuca arundinacea Schreb.) pastures following fertilization with broiler litter. Study sites were located in the Coastal Plain (Alabama), Piedmont (Georgia), and Cumberland Plateau (Tennessee) Major Land Resource Areas of the southeast USA. Litter was applied to supply 70 kg of available N ha−1 based on equations developed by the USDA and the USEPA. Measurements were taken every 2 wk during the course of 2 yr (1995–1996 and 1996–1997) using an in‐situ acetylene‐inhibition technique. Denitrification flux was highly variable, ranging from −20 to 2500 mg N gas m−2 h−1. Total losses of N gas were all <6 kg ha−1 during 150 d after application, representing a loss of <5% of total N applied. Losses from treated plots were not significantly higher than those from control plots. Denitrification rates at these sites were not predictable by any one factor, but seemed to respond only to combinations of various factors such as soil temperature, soil NO3 concentration, and soil water content. Our results indicate that risk of N loss and atmospheric pollution due to denitrification from soils in the southeastern USA is not significantly increased by application of broiler litter at appropriate rates.
Storage and Handling Can Alter the Mineralization Characteristics of Manure
Authors: Van Kessel J. S. , Reeves J. B. , Meisinger J. J. 
Published: July 2010

AbstractIn vitro incubations of manure‐amended soil are frequently used to evaluate manure N and C availability. Manures are typically frozen, refrigerated, or dried prior to analysis. An experiment was designed to evaluate the effects of these manure storage methods on C and N mineralization characteristics. Two dairy slurries were collected and seven treatments, fresh, frozen (4 or 5 wk), refrigerated (1 d, 1 wk 4 wk), freeze‐dried or oven‐dried, were compared. Rates and extents of N and C mineralization were determined by aerobic incubation of slurry‐amended soil at 25°C. Slurry was added at a rate equivalent to 265 kg N ha−1 incorporated into the upper 15 cm of soil. The appearance of NH+4 and NO−3 and the production of CO2 were monitored during 16 wk. Refrigeration or freezing had no effect on slurry N content; however, freeze drying and oven drying resulted in N losses of 30% or more. CO2‐C production followed first‐order kinetics during 9 wk for all treatments with approximately 18 to 26% of the slurry C mineralized. Net mineralization of organic N was minimal in all treatments and was not affected by freezing or refrigerating the slurries. With oven‐dried and freeze‐dried slurries, however, there was a greater immobilization of N when compared with fresh manure. Results indicate that oven drying and freeze drying are unsuitable methods of storage, but the mineralization characteristics of manure are not affected by refrigeration or freezing.
Phosphorus Utilization and Excretion in Pig Production
Authors: Poulsen Hanne Damgaard 
Published: July 2010

AbstractPhosphorus deficiency is known to result in depressed growth and bone abnormalities in pigs (Sus scrofa). As such, practical pig feeding recommendations have over the years aimed at ensuring that pigs would not suffer from P deficiency. This means that a large safety margin has normally been included into the P feeding recommendations in order to compensate for variation in P digestibility in feedstuffs and feed phosphates. However, increasing attention has been devoted to the utilization and excretion of P in pig production over the last decade. Because of the continuous accumulation of P in soil supplied with manure, P utilization and excretion is a matter of great concern, especially in intensive pig‐producing countries, but recent research has shown that it is possible to reduce the P content of manure without affecting pigs' health and productivity. Several aspects have to be addressed. First, it is necessary to identify the content of digestible P rather than total P, since this will give a more precise basis for determination of P requirements for each specific pig category (sows, piglets, and growing‐finishing pigs), allowing safety margins to be reduced. The introduction of digestible P will also enable pig farmers and feed manufacturers to formulate diets that contain the exact amount of digestible P needed by pigs. Phosphorus digestibility in feedstuffs of plant origin is often low, so another approach is to render the intrinsic P more available for pigs. This will reduce the necessity for the addition of extra P as inorganic feed phosphates to pig diets.
Reducing Phosphorus Runoff and Inhibiting Ammonia Loss from Poultry Manure with Aluminum Sulfate
Authors: Moore P. A. , Daniel T. C. , Edwards D. R. 
Published: July 2010

AbstractApplications of aluminum sulfate (Al2(SO4)3 · 14H2O), commonly referred to as alum, to poultry litter have been shown to decrease P runoff from lands fertilized with litter and to inhibit NH3 volatilization. The objectives of this study were to evaluate the effects of alum applications in commercial broiler houses on: (i) NH3 volatilization (inhouse), (ii) poultry production, (iii) litter chemistry, (iv) P runoff following litter application. Two farms were used for this study: one had six poultry houses and the other had four. The litter in half of the houses at each farm was treated with alum; the other houses were controls. Alum was applied at a rate of 1816 kg/house, which corresponded to 0.091 kg/bird. Each year the houses were cleaned in the spring and the litter was broadcast onto paired watersheds in tall fescue at each farm. Results from this study showed that alum applications lowered the litter pH, particularly during the first 3 to 4 wk of each growout. Reductions in litter pH resulted in less NH3 volatilization, which led to reductions in atmospheric NH3 in the alum‐treated houses. Broilers grown on alum‐treated litter were significantly heavier than controls (1.73 kg vs. 1.66 kg). Soluble reactive phosphorus (SRP) concentrations in runoff from pastures fertilized with alum‐treated litter averaged 73% lower than that from normal litter throughout a 3‐yr period. These results indicate that alum‐treatment of poultry litter is a very effective best management practice that reduces nonpoint source pollution while it increases agricultural productivity.
Transfer of Phosphate Ions between Soil and Solution: Perspectives in Soil Testing
Authors: Morel C. , Tunney H. , Plénet D. , Pellerin S. 
Published: July 2010

AbstractPhosphorus inputs must be estimated accurately to optimize the economic return to farmers and minimize P loss from soils to surface waters. Currently, P recommendations are based on the diagnosis of field crop responses by chemically extracted soil P. However, the inability of chemical extraction to characterize plant‐available P limits the reliability of these recommendations. Major sources of P mobilized by plant roots include P ions in solution and those from soil constituents, which replenish and buffer solution. A mechanistic evaluation of soil P supply should therefore be based on the description of P ion transfer between soil constituents and solution. Sorption, desorption, electro‐ultrafiltration (EUF), and isotopic exchange studies show that an adequate modeling of this quantity [Q(CP,t)] of P ions must account for both the concentration of P ions in soil solution (Cp) and time (t). In one long‐term field experiment, the Q(CP,t) description was not affected by crop rotation and mineral fertilization histories; therefore, Q(CP,t) changes are fully explained by CP changes. In two field experiments, CP changes were linearly correlated with the cumulative P budget, inputs, and outputs over years. In three field experiments, the soil type effect on the relative maize (Zea mays L.) response curve was taken into account using the ability of soil P to replenish solution P for 1 d. The residual variance of this diagnosis is halved compared to Olsen's extraction. Although more information is necessary, accuracy is improved when soil testing is based on mobility of P ions.
Integrating Soil Phosphorus Testing into Environmentally Based Agricultural Management Practices
Authors: Sims J. T. , Edwards A. C. , Schoumans O. F. , Simard R. R. 
Published: July 2010

AbstractSoil testing has been an accepted agricultural management practice for decades. Interpretations and fertility recommendations based on soil analyses and the information obtained with soil samples on cropping systems, tillage practices, soil types, manure use, and other parameters have contributed to the increased efficiency of agricultural production. Recently, however, analyses of long‐term trends in soil test P values have shown that soil P in many areas of the world is now excessive, relative to crop P requirements. The role of P in the eutrophication of surface waters and emerging concerns about the human health impacts of toxic algal/dinoflagellate blooms have heightened public awareness of nonpoint source pollution by agricultural P. The greatest concerns are with animal‐based agriculture, where farm and watershed‐scale P surpluses and over‐application of P to soils are common. The need for nutrient‐management plans based on N and P is now an issue of intense debate in the U.S. and Canada. This paper addresses three issues: Should the applications of organic wastes and fertilizers be based on soil P and, if so, what is the most appropriate testing method to assess environmental risk? How can our knowledge of soil P chemistry be integrated with the expertise of hydrologists, agronomists, aquatic ecologists, and others to assess the risks that P in agricultural soils poses to surface waters? And, finally, how can we use soil P testing to evaluate new best management practices (BMPs) now being developed to reduce P transport from soil to water?