bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wind Barriers Suppress Fugitive Dust and Soil‐Derived Airborne Particles in Arid Regions
Authors: Grantz David A. , Vaughn David L. , Farber Robert J. , Kim Bong , Ashbaugh Lowell , VanCuren Tony , Campbell Rich 
Published: July 2010

AbstractAreas of abandoned agricultural land in the Antelope Valley, western Mojave (high) desert of California have proven in our previous studies to be recalcitrant to conventional tillage and revegetation strategies designed to suppress wind erosion of soil and transport of sediment and fugitive dust. These areas represented a continuing source of drifting sand and of coarse and respirable suspended particulate matter. The traditional techniques failed because furrows collapsed and the water holding capacity of the overburden was too low to support seed germination and transplant survival. In this study a variety of wind barriers were evaluated for suppression of sediment transport. Airborne particles were measured with an array of coarse particle samplers at heights of 0.2, 1.0, and 2.0 m above the soil surface. Discrete artificial wind barriers, consisting of widely spaced roughness elements, were effective in suppressing fugitive emissions (>75% at 0.2 m). Wind fences established along the leeward edge of an area of blowing sand, perpendicular to the prevailing wind, significantly decreased fugitive emissions (>90% at 0.2 m). Control was greatest and precision of the measurements was highest under high wind conditions. These techniques provide rapid and effective suppression of fugitive emissions of soil‐derived particles under conditions that resist conventional tillage and revegetation techniques. A simple, indirect procedure for determining local wind velocity erosion thresholds requiring only sampling of wind run and suspended particulate mass compared favorably with direct measurement of saltation as a function of wind velocity.
Ammonia Volatilization from Surface or Incorporated Biosolids by the Addition of Dicyandiamide
Authors: Quemada M. , Lasa B. , Lamsfus C. , Aparicio‐Tejo P. M. 
Published: July 2010

AbstractBiosolids management can affect N gaseous losses, and may be an important tool for sludge N management. The objectives of our experiment were to determine the effect of dicyandiamide (DCD) addition and biosolids placement on (i) ammonia volatilization, and (ii) C mineralization and inorganic N accumulation. Biosolids, treated or untreated with DCD, were either surface‐applied or soil‐incorporated at a rate of 31.7 g of dry solids kg−1 soil, and incubated in flasks at 21°C for 62 d. Free air was renewed at 0.15 L min−1 and NH3 and CO2 in the air flowing out of each flask were collected in traps for each treatment. Inorganic N in soil plus biosolids mixtures was determined at the end of the study. Surface‐applied biosolids treated with DCD lost 71% while nontreated biosolids lost 20% of the applied NH+4‐N. Soil‐incorporated biosolids lost <5% of the applied NH+4‐N. Surface placement of the biosolids enhanced C mineralization, while it did not affect inorganic N accumulation. Addition of DCD to the biosolids did not affect C mineralization, but increased the accumulation of inorganic N. These results suggest that addition of DCD and biosolids placement can be used for managing sludge N.
Assessment of Phytoavailability of Nickel in Soils
Authors: Echevarria G. , Morel J. L. , Fardeau J. C. , Leclerc‐Cessac E. 
Published: July 2010

AbstractMethods are needed for the rapid characterization of the phytoavailable fraction of trace elements in soils to assess the risk of contamination of the food chain and evaluate the impact of waste management practices. This investigation was undertaken to study the phytotavailability of Ni in soils using the isotopic exchange method. Isotopic exchange of 63Ni2+ ions was studied in two soils, a silt loam and a clayey muck, and the isotopic composition of Ni in the soil solution was determined. Plant tests were conducted on the same soils amended with 63Ni2+, and the isotopic composition of Ni in the plant tissues was also measured. The isotopic composition of Ni in soil extracted by DTPA at the end of the culture was also determined. Results showed that the isotopic composition of Ni in the soil solution was identical to the isotopic composition of Ni taken up by plants during the same time. The Ni in the plant came exclusively from the pool of the isotopically exchangeable Ni of the soil. Also, under these experimental conditions, DTPA extracted mainly isotopically exchangeable Ni, reinforcing the validity of this chemical to assess the phytoavailability of Ni. Besides, the phytoavailable soil Ni could be characterized with the intensity, quantity, and capacity factors deduced from isotopic exchange kinetics. The kinetics for which parameters were obtained from short‐term experiments were successfully extrapolated to longer times of exchange corresponding to plant growth which demonstrated that isotopic exchange kinetics is an appropriate tool to assess the truly phytoavailable Ni in soils. This technique requires more data from many different soils before it can be used for routine measurements.
Behavior of the Soil Fumigant Methyl Isothiocyanate in Repacked Soil Columns
Authors: Frick A. , Zebarth B. J. , Szeto S. Y. 
Published: July 2010

AbstractThe environmental fate of the soil fumigant methyl isothiocyanate (MITC) is of concern in areas with groundwater aquifers sensitive to contamination. The objective of this study was to examine the partitioning of soil‐applied MITC among the processes of degradation, adsorption, volatilization to the atmosphere, and leaching from the root zone. Methyl isothiocyanate was injected into repacked soil columns in which leaching loss, volatilization loss, and soil‐extractable MITC were measured, and degradation was calculated by mass balance. The effects of three soil water regimes and four soils with differing clay and organic C contents on MITC behavior were examined. Methyl isothiocyanate degradation was rapid; >90% of applied MITC was degraded in 83 d. Methyl isothiocyanate volatilization loss was positively correlated to soil air‐filled porosity and was suppressed by water application, indicating volatilization was strongly influenced by gas‐phase MITC transport. Under conditions favorable for volatilization, up to 30% of applied MITC volatilized over 35 d. Methyl isothiocyanate retention compared with bromide was relatively small. Methyl isothiocyanate leaching increased with increasing frequency of water application or decreasing delay of water application after MITC injection, and with decreasing degradation and volatilization losses. Under most field conditions, MITC should be removed from the soil root zone by degradation and volatilization before significant leaching occurs. However, because volatilization and degradation losses were very sensitive to soil properties and water regime, site specific soil and climatic conditions immediately after application will have a large influence on MITC leaching potential.
Facilitated Transport of Napropamide by Dissolved Organic Matter in Sewage Sludge‐Amended Soil
Authors: Nelson S. D. , Letey J. , Farmer W. J. , Williams C. F. , Ben‐Hur M. 
Published: July 2010

AbstractThe application of sewage sludge to agricultural soils is practiced to minimize landfill disposal. Organic matter amendments to soil are generally thought to improve soil quality, but pesticide application to these soils may lead to groundwater contamination problems. The complexation of pesticides with a water‐soluble carrier such as dissolved organic matter (DOM) may facilitate chemical movement through soil. Sewage sludge amendments may lead to greater downward movement of organic chemicals if associated with DOM. Napropamide [2‐α‐napthoxy)‐N,N‐diethylpropionamide] was applied to a silt loam soil with (SS) and without (NoSS) sewage sludge application. Laboratory batch equilibrium and soil column studies were performed to determine the potential for herbicide complexation with DOM. Over 98% of the herbicide in soil columns followed typical adsorption and transport behavior as the center of mass of the lower organic matter soil (NoSS) moved twice the depth as that of SS. However, napropamide was detected in the initial leachate eluted from repacked soil columns with steps taken to prevent preferential flow. Napropamide concentrations in the initial leachate of SS were twice that from NoSS with <1.5% of the total applied chemical mass eluting from the bottom of each column. A strong positive relationship was found between napropamide concentration and DOM content in soil leachates. Equilibrium dialysis methods were used to determine that napropamide moving through the soil columns was complexed with DOM. The results show that DOM can facilitate herbicide movement through soil and that sewage sludge‐derived DOM may lead to enhanced chemical transport in sludge‐amended soils.
Assessment of Plant Available Nutrients in Organic Products using an Airlift Bioreactor
Authors: Velthof G. L. , Van Beusichem M. L. , Raijmakers W. M. F. , Janssen B. H. 
Published: July 2010

AbstractWaste products can be diverted from landfill and used as fertilizer when the nutrient availability in these products can be reliably determined. The aim of this study was to determine whether aerobic incubation in an internal‐loop airlift bioreactor is a reliable method for assessing plant‐available N and P in organic waste products. Published results of pot experiments with ryegrass were used as a reference for available N and P. The incubation in the airlift reactor was also compared with conventional incubation in polyethylene bags. Samples of eight different organic products were incubated for 20 d in airlift reactors maintained at pH 5. The plant‐available N fraction was determined by measuring inorganic concentrations in the reactor solution, and the plant‐available P fraction was determined by extraction of P from the solution using iron oxide‐coated filter paper. The available N fraction in the organic products as determined in the airlift reactor was closely related (R2 = 0.73) with the N uptake by ryegrass (Lolium perenne L.). For P, there was no relationship between the P extracted in the airlift reactor and the P uptake by ryegrass. The incubation in the airlift reactors to assess plant‐available N in organic waste products was more rapid than the pot experiment with ryegrass and was more reliable than the conventional incubation in polyethylene bags. We recommend that plant‐available N and P be determined in different airlift reactors, because of possible pH‐related P dissolution and because the iron oxide‐coated filters contain NH4+ which may hamper determination of N.
Regulation of Organic Matter Decomposition and Nutrient Release in a Wetland Soil
Authors: McLatchey G. P. , Reddy K. R. 
Published: July 2010

AbstractIn wetland soils, the supply of O2 to soil is greatly reduced; thus, alternate electron acceptors must be utilized by the microbial populations during decomposition of organic matter. These changes in the supply of electron acceptors affect the size of microbial populations, enzyme production, and decomposition of organic matter. A laboratory study was conducted to determine the role of redox potential (Eh) and availability of electron acceptors on selected microbial processes regulating organic matter decomposition and nutrient release. Soil Eh was maintained approximately at 620, 310, −100, and −220 mV, with the addition of O2, NO−3, SO2−4, and HCO−3, respectively. The soil microbial biomass, as determined by fumigation‐extraction methods, gradually decreased as soils became more reduced. Microbial biomass C ranged from 354 to 10 100 mg C kg−1 soil (dw), while microbial biomass N and P ranged from 140 to 439 mg N kg−1 soil (dw), and 64 to 180 mg P kg−1 soil (dw), respectively. Organic C, N, and P mineralization rates decreased as soils became more reduced. Organic C mineralization rates measured by CO2 production ranged from 51 to 400 mg C kg−1 (dw) d−1. Corresponding values of organic N and P mineralization rates ranged from 21 to 150 mg N kg−1 (dw) d−1, and 6 to 107 mg P kg−1 (dw) d−1, respectively. Significant relationships (P < 0.01) were observed among the soil enzyme activities, microbial biomass, and the mineralization rates of C, N, and P.
Recovery of Biosolids‐Applied Heavy Metals Sixteen Years after Application
Authors: Sloan J. J. , Dowdy R. H. , Dolan M. S. 
Published: July 2010

AbstractLittle is known of the long‐term fate of biosolids‐applied heavy metals in soil. The objective of this study was to quantify percent recovery of biosolids‐applied heavy metals in a well‐drained soil. Three annual applications of biosolids resulted in cumulative biosolids loadings of 0, 60, 120, and 180 Mg ha−1. Cumulative metal loadings for the 180 Mg ha−1 biosolids rate were 25, 141, 127, 43, 173, and 348 kg ha−1 for Cd, Cr, Cu, Ni, Pb, and Zn, respectively. Soils were sampled to a depth of 0.9 m. Soil organic carbon (OC) was measured. Soil was extracted with 1 M HNO3 and metals were determined in the supernatants. Soil OC concentrations were linearly correlated to biosolids loadings and did not change significantly during the 16 yr after biosolids applications. Concentrations of extractable Cd, Cr, Cu, Ni, Pb, and Zn in biosolids‐treated soils were much greater than the control to a depth of 0.30 m (P < 0.01), slightly greater at 0.30 to 0.45 m (P < 0.05) and same as the control below 0.45 m. For the 180 Mg ha−1 biosolids loading, percent recoveries for Cd, Cr, Cu, Ni, Pb, and Zn were 112, 59, 119, 114, 102, and 97%, respectively. Low recovery of Cr was probably due to incomplete extraction from the soil. These results show that complete recovery of biosolids‐applied heavy metals is possible when plot size is large enough to prevent cross‐mixing of treated soils during tillage operations and when sediment losses are minimal.
Sorption and Desorption of Atrazine by Sludge‐Amended Soil: Dissolved Organic Matter Effects
Authors: Celis R. , Barriuso E. , Houot S. 
Published: July 2010

AbstractAddition of insoluble and soluble organic C to soil through management practices, such as sewage sludge (SS) application, may greatly alter pesticide sorption‐desorption in soil. Batch equilibrium techniques were used to determine the effects of four sewage sludges (liquid‐SS, solid‐SS, limed‐SS, and composted‐SS) and their water dissolved organic matter (DOM), on the sorption‐desorption of atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐1,3,5‐triazine) by a silt loam soil. Atrazine sorption on the sludges increased in the order: iimed‐SS < liquid‐SS < solid‐SS < composted‐SS. Sludge addition to soil increased atrazine sorption in the same order, although the effectiveness of the mixtures to sorb atrazine was lower than expected from the sorption capacity of the isolated soil and sludges. The effects of the DOM extracted from the different sludges on atrazine sorption varied with sewage sludge. For liquid‐, solid‐, and limed‐SS, DOM reduced atrazine sorption on soil. A low association between these DOMs and atrazine was measured in solution by dialysis technique, and indicated that processes at the soil/solution interface may have contributed to reduce atrazine sorption. In contrast, enhanced atrazine sorption in the presence of DOM extracted from composted‐SS indicated atrazine was bound by DOM associated with the soil. Atrazine desorption from soil increased in the presence of DOM from all four sludges; however, DOMs had little effect on atrazine desorption from sludge and from sludge‐amended soil. Interactions of soil surfaces with organic amendments and their DOM are shown in this work as a major process determining atrazine sorption‐desorption in amended soil.
Evaluation and Comparison of Five Simulation Models for Estimating Water Drainage Fluxes under Corn
Authors: Jabro J. D. , Toth J. D. , Fox R. H. 
Published: July 2010

AbstractThe simulation accuracies of five water quality models, LEACHW, MACRO, NCSWAP, SLIM, and SOIL to predict the amount of drainage water were evaluated and compared to field data from a 5‐yr leaching experiment. The study was conducted on Hagerstown silt loam soil (fine, mixed, mesic Typic Hapludalf). Drainage fluxes below the rooting zone of corn were measured with pan lysimeters in 1988–1989, 1989–1990, 1990–1991, 1991–1992, and 1992–1993. A series of 18 zero‐tension pan lysimeters (0.465 m2 area) were installed at a depth of 1.2 m to collect drainage water at approximately the rooting depth of corn. All five models were calibrated to the site conditions using data from 1989 to 1990. The calibrated inputs were then used to evaluate the models' simulating accuracy using 1988–1989, 1990–1991, 1991–1992, and 1992–1993 drainage data. The cumulative annual simulations of drainage water from each model were compared to the mean of pan efficiency corrected measured data for these five sampling years. Simulated results for all five models fell within 95% confidence intervals of the measured data. Validation simulations of drainage fluxes were about as accurate as calibration simulations. The statistical analyses indicated that all five models performed well and have the potential to accurately predict the amount of drainage fluxes below the 1.2 m depth under corn cropping system without the need to calibrate the model for each year. There were small differences among the overall performances of the models for simulating drainage losses, but these differences were not significant using one‐way analysis of variance.
Harvest Impacts on Forest Outflow in Coastal North Carolina
Authors: Lebo Martin E. , Herrmann Robert B. 
Published: July 2010

AbstractDitch networks are common in coastal North Carolina to improve drainage necessary for crop and timber production. Forest outflow at three locations in a managed loblolly pine (Pinus taeda L.) forest with artificial drainage was monitored during 1986 to 1994 to evaluate how harvest and other normal silvicultural operations affect annual and seasonal outflow characteristics. Increased outflow and small increases in nutrient concentrations occurred following tree harvest; N concentrations for inorganic and organic fractions increased by 0.09 to 0.14 and 0.24 to 0.26 mg L−1, respectively, while total P increased by 0 to 0.07 mg L−1. For a 3‐yr period beginning at harvest, increases in annual outflow, N export, and P export were 111 to 164 mm, 2.1 to 2.2 kg N ha−1 yr−1, and 0.12 to 0.36 kg P ha−1 yr−1, respectively, compared with baseline levels. Outflow and nutrient concentrations returned to baseline levels within 2 to 3 yr. Negligible change in the total suspended solids (TSS) concentration occurred following harvest and site preparation. On a landscape scale, these relatively small increases in annual nutrient exports associated with harvest and site preparation are further reduced to 4 to 7% above baseline levels when placed in the context of a 30‐ to 35‐yr growth cycle for loblolly pine in coastal North Carolina.
Interaction between Manure and Tillage System on Phosphorus Uptake and Runoff Losses
Authors: Ginting D. , Moncrief J. F. , Gupta S. C. , Evans S. D. 
Published: July 2010

AbstractApplication of manure on soils having high P test has raised concerns over the eutrophication of lakes and rivers. The objective of this study was to evaluate the effects of one time application of 164 kg P ha−1 from solid beef (Bos taurus L.) manure on soil Olsen P dynamics, P uptake by corn (Zea mays L.) grain, and P losses as total P (TP), particulate P (PP), and dissolved molybdate reactive P (DMRP) in both snowmelt and rainfall runoff under ridge tillage (RT) and moldboard plow (MP) systems from 1992 to 1994. Soil P was consistently higher in the manure than no manure treated plots (17.9 vs. 12.3 mg kg−1 in 1993 and 23.7 vs. 13.8 mg kg−1 in 1994). Phosphorus uptake was greater from the manure than no manure treated plots (24.5 vs. 19.8 kg ha−1 and 23.5 vs. 18.8 kg ha−1). Annual PP and TP losses were either similar or lower from manure than no manure treated plots. Particulate P losses by rainfall runoff were lower from the RT vs. MP systems (0.25 vs. 1.95 kg ha−1 in 1993 and 0.06 vs. 0.65 kg ha−1 and 1994). The opposite was apparent for DMRP losses in snowmelt, which were higher from the RT than MP system (0.11 vs. 0.01 kg ha−1 and 0.14 vs. 0.03 kg ha−1). The RT system is an environmentally better system than the MP system due to its substantial reduction in annual PP and TP losses.
Biogeochemical Characteristics of the Everglades Sloughs
Authors: Vaithiyanathan Panchabi , Richardson Curtis J. 
Published: July 2010

AbstractEverglades sloughs are alkaline hardwater systems. Mean water column dissolved phosphate (5 µg/L) and TP (9 µg/L) concentrations in the sloughs are typical of oligotrophic waters. Molar ratios of dissolved inorganic N and P (DIN:DIP = 28:1) in the surface waters suggest that P may be limiting the aquatic primary productivity in the Everglades sloughs. Variations in water column TP and TN in the sloughs were inversely related to the water depth fluctuations (P <0.0001) suggesting a strong link with hydrology. Periphyton and macrophytes in the sloughs exhibited N/P ratios indicative of depletion in P relative to N. The N/P ratios in the Everglades slough communities were in the upper range of values reported for aquatic plants from other ecosystems. The N/P ratios in periphyton were higher than macrophytes suggesting that P depletion was even greater for periphyton. As a result any introduced inorganic phosphate was taken up rapidly by the periphyton reducing the water column PO4‐P to near background levels. Our results suggest that C/N/P ratios of the periphyton provide a reliable measure of the P‐status of the Everglades sloughs whereas the water column P concentration may not truly reflect the P‐status of the system. Periphyton mat also plays an important role in oxygenating the water column of the sloughs. Experimental results show that a decline in periphyton mat cover will result in a decrease in the water column dissolved oxygen concentration and may also lead to other ecosystem changes by enhancing the PAR availability to the slough bottom.
Biodegradation of 2,4‐D in a Noncontaminated Grassland Soil Profile
Authors: Shaw Liz J. , Burns Richard G. 
Published: July 2010

AbstractPrediction of groundwater contamination and the development of rational bioremediation strategies require a greater understanding of xenobiotic biodegradation at the soil profile scale. We studied 2,4‐dichlorophenoxyacetic acid (2,4‐D) biodegradation for up to 83 d in soil samples collected in 10‐cm depth increments from a noncontaminated soil profile (0–50 cm), and examined factors that influenced biodegradation in the subsoil (40–50 cm). For the four samples collected from 0 to 40 cm, total evolution of 14CO2 from 14C‐ring‐UL‐2,4‐D (20 mg kg−1, 0.25 MBq kg−1) was 50.02 to 60.46% (maximum rate = 4.84% d−1 at 10–20 cm) at the end of the mineralization phase. Subsoil (40–50 cm) mineralization was either 5.47% (maximum rate = 0.113% d−1) or 56.1% (maximum rate = 2.67% d−1) after 83 d. Enhanced mineralization of successive 2,4‐D applications was recorded in all topsoil (0–10 cm) samples and in the subsoil replicates that initially mineralized > 50%. Measurements of 2,4‐D disappearance and most probable number analysis corresponded well with the biodegradation data. Inoculation of subsoil with topsoil (10%) increased 2,4‐D mineralization in the 5% soil to > 50%, whereas amendment with N, P, K, and/or organic C sources (acetate, catechol, vanillin, 3,5‐dihydroxybenzoic acid) did not. We conclude that the subsoil contained a low number of unevenly distributed microorganisms capable of using 2,4‐D as a source of C and energy such that not all the subsamples had competent microorganisms present.