bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alum Amendment Effects on Phosphorus Release and Distribution in Poultry Litter–Amended Sandy Soils
Authors: Staats Kristin E. , Arai Yuji , Sparks Donald L. 
Published: June 2010

ABSTRACTIncreased poultry production has contributed to excess nutrient problems in Atlantic Coastal Plain soils due to land application of poultry litter (PL). Aluminum sulfate [alum, Al2(SO4)3·14H2O] amendment of PL effectively reduces soluble phosphorus (P) in the PL; however, the effects of these litters when added to acidic, sandy soils are not well understood. The objective of this study was to investigate the efficacy of alum‐amended poultry litter in reducing P release from three Delaware Coastal Plain soils: Evesboro loamy sand (Ev; excessively drained, mesic, coated Typic Quartzipsamments), Rumford loamy sand (Ru; well drained, coarse‐loamy, siliceous, subactive, thermic Typic Hapludults), and Pocomoke sandy loam (Pm; very poorly drained, coarse‐loamy, siliceous, active, thermic Typic Umbraquults). Long‐term (25 d) and short‐term (24 h) desorption studies were conducted, in addition to chemical extractions and kinetic modeling, to observe the changes that alum‐amended versus unamended PL caused in the soils. The Ev, Ru, and Pm soils were incubated with 9 Mg ha−1 of alum‐amended or unamended PL. Long‐term desorption (25 d) of the incubated material resulted in approximately 13.5% (Ev), 12.7% (Ru), and 13.3% (Pm) reductions in cumulative P desorbed when comparing soil treated with unamended and alum‐amended PL. In addition, the P release from the soil treated with alum‐amended litter was not significantly different from the control (soil alone). Short‐term desorption (24 h) showed 7.3% (Ev), 15.4% (Ru), and 20% (Pm) reductions. The overall implication from this study is that the use of alum as a PL amendment is useful in coarse‐textured soils of the Coastal Plain. With increased application of alum‐amended PL, more significant decreases may be possible with little or no effect on soil quality.
Sorption and Detoxification of Toxic Compounds by a Bifunctional Organoclay
Authors: Groisman Ludmila , Rav‐Acha Chaim , Gerstl Zev , Mingelgrin Uri 
Published: June 2010

ABSTRACTOrganoclays are excellent sorbents for nonionic contaminants and therefore may have many environmental applications. A major limitation on the use of organoclays is that the contaminant merely changes its location from one environmental compartment to another while still remaining intact. In this study, a new type of organoclay, termed a bifunctional organoclay, has been prepared. It is able not only to sorb organophosphate pesticides, but also to catalyze their hydrolysis, and thereby detoxify them. The bifunctional organoclay prepared in this study is based on sodium montmorillonite, in which the inorganic counter ions are replaced by N‐decyl‐N,N‐dimethyl‐N‐(2‐aminoethyl) ammonium (DDMAEA). The detoxifying capacity of this organoclay for two organophosphate pesticides, methyl parathion [O,O‐dimethyl O‐(p‐nitrophenyl) thionophosphate] and tetrachlorvinphos [2‐chloro‐1‐(2,4,5‐trichlorophenyl)ethenyl dimethyl phosphate], was demonstrated. It was shown that although the sorption of these pesticides on the bifunctional organoclay is very similar to that on N‐decyl‐N,N,N‐trimethyl ammonium (DTMA) organoclay (the corresponding nonbifunctional organoclay), the hydrolysis of these pesticides is substantially enhanced only by the bifunctional organoclay. The half‐life for the hydrolysis of the investigated pesticides in the presence of the bifunctional organoclay is about 12 times less than for their spontaneous hydrolysis, and the enhancement is even more pronounced relative to the hydrolysis of these pesticides in the presence of the DTMA organoclay (which actually inhibits their hydrolysis). Based on kinetic measurements, the pKa of the ethylamino group of the bifunctional organoclay was estimated to be around 9.0. It is postulated that the catalytic effect of the bifunctional organoclay can be attributed to a nucleophilic attack of the unprotonated ethylamino group of the organoclay on the organophosphate ester.
Phosphorus Transfer in Surface Runoff from Intensive Pasture Systems at Various Scales
Authors: Dougherty Warwick J. , Fleming Nigel K. , Cox Jim W. , Chittleborough David J. 
Published: June 2010

ABSTRACTPhosphorus transfer in runoff from intensive pasture systems has been extensively researched at a range of scales. However, integration of data from the range of scales has been limited. This paper presents a conceptual model of P transfer that incorporates landscape effects and reviews the research relating to P transfer at a range of scales in light of this model. The contribution of inorganic P sources to P transfer is relatively well understood, but the contribution of organic P to P transfer is still relatively poorly defined. Phosphorus transfer has been studied at laboratory, profile, plot, field, and watershed scales. The majority of research investigating the processes of P transfer (as distinct from merely quantifying P transfer) has been undertaken at the plot scale. However, there is a growing need to integrate data gathered at a range of scales so that more effective strategies to reduce P transfer can be identified. This has been hindered by the lack of a clear conceptual framework to describe differences in the processes of P transfer at the various scales. The interaction of hydrological (transport) factors with P source factors, and their relationship to scale, require further examination. Runoff‐generating areas are highly variable, both temporally and spatially. Improvement in the understanding and identification of these areas will contribute to increased effectiveness of strategies aimed at reducing P transfers in runoff. A thorough consideration of scale effects using the conceptual model of P transfer outlined in this paper will facilitate the development of improved strategies for reducing P losses in runoff.
Trace Element Concentrations in Soil, Corn Leaves, and Grain after Cessation of Biosolids Applications
Authors: Granato Thomas C. , Pietz Richard I. , Knafl George J. , Carlson Carl R. , Tata Prakasam , Lue‐Hing Cecil 
Published: June 2010

ABSTRACTFrom 1974 to 1984, 543 Mg ha−1of biosolids were applied to portions of a land‐reclamation site in Fulton County, IL. Soil organic C increased to 5.1% then decreased significantly (p< 0.01) to 3.8% following cessation of biosolids applications (1985–1997). Metal concentrations in amended soils (1995–1997) were not significantly different (p> 0.05) (Ni and Zn) or were significantly lower (p< 0.05) (6.4% for Cd and 8.4% for Cu) than concentrations from 1985–1987. For the same biosolids‐amended fields, metal concentrations in corn (Zea maysL.) either remained the same (p> 0.05, grain Cu and Zn) or decreased (p< 0.05, grain Cd and Ni, leaf Cd, Cu, Ni, Zn) for plants grown in 1995–1997 compared with plants grown immediately following termination of biosolids applications (1985–1987). Biosolids application increased (p< 0.05) Cd and Zn concentrations in grain compared with unamended fields (0.01 to 0.10 mg kg−1for Cd and 23 to 28 mg kg−1for Zn) but had no effect (p> 0.05) on grain Ni concentrations. Biosolids reduced (p< 0.05) Cu concentration in grain compared with grain from unamended fields (1.9 to 1.5 mg kg−1). Biosolids increased (p< 0.05) Cd, Ni, and Zn concentrations in leaves compared with unamended fields (0.3 to 5.6 mg kg−1for Cd, 0.2 to 0.5 mg kg−1for Ni, and 32 to 87 mg kg−1for Zn), but had no significant effect (p> 0.05) on leaf Cu concentrations. Based on results from this field study, USEPA's Part 503 risk model overpredicted transfer of these metals from biosolids‐amended soil to corn.
Residual and Contact Herbicide Transport through Field Lysimeters via Preferential Flow
Authors: Malone R. W. , Shipitalo M. J. , Wauchope R. D. , Sumner H. 
Published: June 2010

ABSTRACTUsage of glyphosate [N‐(phosphonomethyl)‐glycine] and glufosinate [2‐amino‐4‐(hydroxy‐methylphosphinyl)butanoic acid] may reduce the environmental impact of agriculture because they are more strongly sorbed to soil and may be less toxic than many of the residual herbicides they replace. Preferential flow complicates the picture, because due to this process, even strongly sorbed chemicals can move quickly to ground water. Therefore, four monolith lysimeters (8.1 m2 by 2.4 m deep) were used to investigate leaching of contact and residual herbicides under a worst‐case scenario. Glufosinate, atrazine (6‐chloro‐N2‐ethyl‐N4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine), alachlor [2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl) acetamide], and linuron (3‐3,4‐dichlorophenyl‐1‐methoxy‐1‐methylurea) were applied in 1999 before corn (Zea mays L.) planting and glyphosate, alachlor, and metribuzin [4‐amino‐6‐(1,1‐dimethylethyl)‐3‐(methylthio)‐1,2,4‐triazin‐5(4H)‐one] were applied in 2000 before soybean [Glycine max (L.) Merr.] planting. A high‐intensity rainfall was applied shortly after herbicide application both years. Most alachlor, metribuzin, atrazine, and linuron losses occurred within 1.1 d of rainfall initiation and the peak concentration of the herbicides coincided (within 0.1 d of rainfall initiation in 2000). More of the applied metribuzin leached compared with alachlor during the first 1.1 d after rainfall initiation (2.2% vs. 0.035%, P < 0.05). In 1999, 10 of 24 discrete samples contained atrazine above the maximum contaminant level (atrazine maximum contaminant level [MCL] = 3 μg L−1) while only one discrete sample contained glufosinate (19 μg L−1, estimated MCL = 150 μg L−1). The results indicate that because of preferential flow, the breakthrough time of herbicides was independent of their sorptive properties but the transport amount was dependent on the herbicide properties. Even with preferential flow, glyphosate and glufosinate were not transported to 2.4 m at concentrations approaching environmental concern.
Effect of Combined Application of Methyl Isothiocyanate and Chloropicrin on Their Transformation
Authors: Zheng Wei , Yates Scott R. , Papiernik Sharon K. , Guo Mingxin 
Published: June 2010

ABSTRACTCombining several soil fumigants to increase the broad spectrum of pest control is a common fumigation practice in current production agriculture. In this study, we investigated the effect of combined application of chloropicrin and methyl isothiocyanate (MITC) on their transformations and persistence in the environment. In aqueous solution, no direct reaction between MITC and chloropicrin occurred and relatively slow rates of hydrolysis of these compounds were observed in aquatic environments free of suspended solids. The transformation of chloropicrin, however, was accelerated in aqueous solution with MITC because of a reduction reaction with bisulfide (HS−), which is a by‐product of MITC hydrolysis. In soil, when fumigants were applied simultaneously, the degradation of MITC was suppressed under the bi‐fumigant application due to the inhibition of soil microbial activity and a possible abiotic competition with chloropicrin for a limited number of reaction sites on the surface of soil particles. However, the degradation rate of chloropicrin was significantly enhanced in the bi‐fumigant soil system, which was primarily attributed to the reaction of chloropicrin and HS− Two sequential application approaches were developed to investigate the feasibility of the combined application of metam sodium (parent compound of MITC) and chloropicrin in soil and assess their potential effects on environmental fate. For both application sequences, the degradation of chloropicrin was accelerated and that of MITC, as a major breakdown product of metam sodium, was inhibited in soil.
Effects of Near‐Surface Hydraulic Gradients on Nitrate and Phosphorus Losses in Surface Runoff
Authors: Zheng Fen‐Li , Huang Chi‐Hua , Norton L. Darrell 
Published: June 2010

ABSTRACTPhosphorous (P) and nitrogen (N) in runoff from agricultural fields are key components of nonpoint‐source pollution and can accelerate eutrophication of surface waters. A laboratory study was designed to evaluate effects of near‐surface hydraulic gradients on P and N losses in surface runoff from soil pans at 5% slope under simulated rainfall. Experimental treatments included three rates of fertilizer input (control [no fertilizer input], low [40 kg P ha−1, 100 kg N ha−1], and high [80 kg P ha−1, 200 kg N ha−1]) and four near‐surface hydraulic gradients (free drainage [FD], saturation [Sa], artesian seepage without rain [Sp], and artesian seepage with rain [Sp + R]). Simulated rainfall of 50 mm h−1 was applied for 90 min. The results showed that near‐surface hydraulic gradients have dramatic effects on NO3–N and PO4–P losses and runoff water quality. Under the low fertilizer treatment, the average concentrations in surface runoff from FD, Sa, Sp, and Sp + R were 0.08, 2.20, 529.5, and 71.8 mg L−1 for NO3–N and 0.11, 0.54, 0.91, and 0.72 mg L−1 for PO4–P, respectively. Similar trends were observed for the concentrations of NO3–N and PO4–P under the high fertilizer treatment. The total NO3–N loss under the FD treatment was only 0.01% of the applied nitrogen, while under the Sp and Sp + R treatments, the total NO3–N loss was 11 to 16% of the applied nitrogen. These results show that artesian seepage could make a significant contribution to water quality problems.
Uncertainty Assessment of the Model RICEWQ in Northern Italy
Authors: Miao Zewei , Trevisan Marco , Capri Ettore , Padovani Laura , Del Re Attilio A. M. 
Published: June 2010

ABSTRACTModel predictions are often seriously affected by uncertainties arising from many sources. Ignoring the uncertainty associated with model predictions may result in misleading interpretations when the model is used by a decision‐maker for risk assessment. In this paper, an analysis of uncertainty was performed to estimate the uncertainty of model predictions and to screen out crucial variables using a Monte Carlo stochastic approach and a number of statistical methods, including ANOVA and stepwise multiple regression. The model studied was RICEWQ (Version 1.6.1), which was used to forecast pesticide fate in paddy fields. The results demonstrated that the paddy runoff concentration predicted by RICEWQ was in agreement with field measurements and the model can be applied to simulate pesticide fate at field scale. Model uncertainty was acceptable, runoff predictions conformed to a log‐normal distribution with a short right tail, and predictions were reliable at field scale due to the narrow spread of uncertainty distribution. The main contribution of input variables to model uncertainty resulted from spatial (sediment–water partition coefficient and mixing depth to allow direct partitioning to bed) and management (time and rate of application) parameters, and weather conditions. Therefore, these crucial parameters should be carefully parameterized or precisely determined in each site‐specific paddy field before the application of the model, since small errors of these parameters may induce large uncertainty of model outputs.
Efficacy of Vegetated Buffer Strips for RetainingCryptosporidium parvum
Authors: Tate Kenneth W. , Pereira Maria Das Gracas C. , Atwill Edward R. 
Published: June 2010

ABSTRACTOverland and shallow subsurface hydrologic transport of pathogenicCryptosporidium parvumoocysts from cattle feces into surface drinking water supplies is a major concern on annual grasslands in California's central and southern Sierra Nevada foothills. Soil boxes (0.5 m wide × 1.1 m long × 0.3 m deep) were used to evaluate the ability of grass vegetated buffer strips to retain 2 × 108spikedC. parvumoocysts in 200‐g fecal deposits during simulated rainfall intensities of 30 to 47.5 mm/h over 2 h. Buffers were comprised of Ahwahnee sandy loam (coarse‐loamy, mixed, active, thermic Mollic Haploxeralfs; 78:18:4 sand to silt to clay ratio; dry bulk density = 1.4 g/cm3) set at 5 to 20% land slope, and ≥95% grass cover (grass stubble height = 10 cm; biomass = 900 kg/ha dry weight). Total number of oocysts discharged from each soil box (combined overland and subsurface flow) during the 120‐min simulation ranged from 1.5 × 106to 23.9 × 106oocysts. Observed overall mean log10reduction of totalC. parvumflux per meter of vegetated buffer was 1.44, 1.19, and 1.18 for buffers at 5, 12, and 20% land slope, respectively. Rainfall application rate (mm/h) was strongly associated with oocyst flux from these vegetated buffers, resulting in a decrease of 2 to 4% in the log10reduction per meter buffer for every additional mm/h applied to the soil box. These results support the use of strategically placed vegetated buffers as one of several management strategies that can reduce the risk of waterborneC. parvumattributable to extensive cattle grazing on annual grassland watersheds.
Transport of Phosphate through Artificial Macropores during Film and Pulse Flow
Authors: Gjettermann Birgitte , Hansen Hans Christian B. , Jensen Henry E. , Hansen S⊘ren 
Published: June 2010

ABSTRACTFlow through artificial macropores may occur as a water film along the macropore walls (film flow) or as moving water segments separated by air bubbles (pulse flow). To investigate the effect of macropore flow pattern (i.e., film and pulse flow) on the interaction of solutes with macropore walls, we studied orthophosphate (P) transport and sorption in artificial macropores. The experimental setup consisted of a column (height = 20 cm, diameter = 20 cm) homogenously packed with glass beads and fitted at outflow with a vertical artificial macropore placed below the column. The artificial macropore consisted of ceramic tubes (3 or 8 mm i.d.; 31.5 cm long) coated on the inside with iron oxide serving as phosphate sorbents. An orthophosphate solution containing 0.04 mg P L−1 was applied at a rate of 9 to 12 mm h−1 to the column, eventually causing macropore flow. In the 8‐mm‐i.d. tubes only film flow occurred. Pulse flow was dominating in the 3‐mm‐i.d. tubes. Generally, the flow patterns were reproducible and seldom did pulse flow replaced film flow or vice versa. During film flow, a significantly larger decrease in macropore P concentration per tube was observed relative to that with pulse flow events. However, pulse and film flow lead to almost the same amounts of P sorbed per unit surface area when exposed to the same solute P concentration. Comparison with P sorption capacity experiments indicated that the sorption rate, rather than the sorption capacity, controls the amount of sorbed P during macropore flow in the studied system.
Simulating Urban Waste Compost Effects on Carbon and Nitrogen Dynamics Using a Biochemical Index
Authors: Gabrielle Benoît , Da‐Silveira Jeanne , Houot Sabine , Francou Cédric 
Published: June 2010

ABSTRACTComposting has emerged as a valuable route for the disposal of urban waste, with the prospect of applying composts on arable fields as organic amendments. Proper management of urban waste composts (UWCs) requires a capacity to predict their effects on carbon and nitrogen dynamics in the field, an issue in which simulation models are expected to play a prominent role. However, the parameterization of soil organic amendments within such models generally requires laboratory incubation data. Here, we evaluated the benefit of using a biochemical index based on Van Soest organic matter fractions to parameterize a deterministic model of soil C and N dynamics, NCSOIL, as compared with a standard alternative based on laboratory incubation data. The data included C mineralization and inorganic N dynamics in samples of a silt loam soil (Typic Hapludalf) mixed with various types of UWC and farmyard manure. NCSOIL successfully predicted the various nitrogen mineralization–immobilization patterns observed, but underestimated CO2 release by 10 to 30% with the less stable amendments. The parameterization based on the biochemical index achieved a prediction error significantly larger than the standard parameterization in only 10% of the tested cases, and provided an acceptable fit to experimental data. The decomposition rates and C to N ratios of compost organic matter varied chiefly according to the type of waste processed. However, 62 to 66% of their variance could be explained by the biochemical index. We thus suggest using the latter to parameterize organic amendments in C and N models as a substitute for time‐consuming laboratory incubations.
Denitrification in a Coastal Plain Riparian Zone Contiguous to a Heavily Loaded Swine Wastewater Spray Field
Authors: Hunt P. G. , Matheny T. A. , Stone K. C. 
Published: June 2010

ABSTRACTRiparian zones are recognized as landscape features that buffer streams from pollutants, particularly nitrogen. The objectives of this experiment were to (i) assess denitrification activity within a riparian zone and (ii) determine the influence of physical, chemical, and landscape features on denitrification. This experiment was conducted from 1994 to 1997 in North Carolina on a riparian zone contiguous to a spray field that was heavily loaded with swine lagoon wastewater. Denitrification enzyme activity (DEA) was measured on soils collected from (i) the soil surface, (ii) midway between the soil surface and water table, and (iii) above the water table. The DEA ranged from 3 to 1660 μg N2O‐N kg−1 soil h−1 The DEA was highest next to the stream and lowest next to the spray field. Nitrate was found to be the limiting factor for denitrification. The DEA generally decreased with soil depth; means for the surface, middle, and bottom depths were 147, 83, and 67 μg N2O‐N kg−1 soil h−1, respectively. These DEA values are higher than those reported for riparian zones adjoining cropland of the southeastern United States, but are lower than those reported for a constructed wetland used for treatment of swine wastewater. Regression analysis indicated that soil total nitrogen was the highest single factor correlated to DEA (r2 = 0.65). The inclusion of water table depth, soil depth, and distance from the spray field improved the R2 to 0.86. This riparian zone possessed sufficient soil area with high denitrifying conditions to be a significant factor in the removal of excess nitrogen in the ground water.
Interpreting Science in the Real World for Sustainable Land Application
Authors: Bastian Robert K. 
Published: June 2010

ABSTRACTToday's land application practices are designed to effectively treat wastes, and have evolved from earlier practices that centered on cheap disposal with less regard for environmental protection. The major objectives of this paper are to (i) review how current land application practices, and our understanding of them, have evolved over time and (ii) explore how science is used (and sometimes misused or ignored) in the development of design, regulation, and management of sustainable land application. Land treatment technologies have been used effectively for the treatment and recycling of many types of wastewaters and organic residuals for many years. Extensive research and demonstration efforts, as well as experience with pilot‐ and field‐scale projects, have provided the information about soil reactions with contaminants in wastewater and organic residuals needed to design and operate sustainable land application projects. Still, systematic research programs are as important today as ever to support studies aimed at producing information on how soil‐based treatment and recycling systems work, to address new areas of concerns as they arise, and continue to improve the overall design, performance, and reliability of land application systems as sustainable soil treatment and recycling systems.