bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of Reclaimed Mined Land With and Without Topsoil
Authors: Chong S. K. , Becker M. A. , Moore S. M. , Weaver G. T. 
Published: July 2010

AbstractResearch was conducted on two field plots to ascertain whether topsoil restoration is necessary hydrologically and physically in mined land reclamation. Plot 1 was reclaimed with mixed B‐ and C‐horizon material, and Plot 2 with the same material as Plot 1 but with 0.2 m of topsoil added on the surface. The mixed B and C materials were restored with a shiftable conveyor belt and the stockpiled topsoil was spread by earth scrapers. Both field plots were divided into 25 subplots. The hydrological and physical characterization was limited to the top 0.2 m of the soil. The result showed that nontopsoil had an average bulk density of 1.5 Mg m−3 which is about 15% higher than that of the topsoil plot. The hydraulic conductivity, macroporosity, and drainage rate of topsoil materials were higher, but the sorptivity and infiltration rate of the two plots were not significantly different. Since this research was limited to 0.2 m of surface soil, it did not provide enough information to decide whether topsoil replacement is necessary or whether B and C material is an adequate rooting medium. The study did demonstrate a simple technique for detailed characterization of the physical and hydrological properties of reclaimed mined land.
Time‐dependent Changes in Soluble Organics, Copper, Nickel, and Zinc from Sludge Amended Soils
Authors: Dudley L. M. , Mc Neal B. L. , Baham J. E. 
Published: July 2010

AbstractAn acidic western Washington soil and a near‐neutral eastern Washington soil were each mixed with anaerobically digested Seattle‐METRO sewage sludge and incubated in triplicate at 25 ± 2°C and approximately −33 kPa water potential for 1, 2, and 4 d and 1, 2, 4, 10 and 30 weeks. At the end of each incubation period, saturation pastes were made using 0.01 M CaCl2 and vacuum extracted. Total soluble C, Cu, Ni and Zn, as ‐ell as NH4 + NH3, NO3‐N, ortho‐P, and pH were measured in the extracts. High NH4 + NH3 values produced in the first 2 weeks of incubation caused the pH to increase into the alkaline range. Soluble C values increased during this period, and soluble Cu values increased despite the increasing pH, apparently because of organic complex formation. Soluble Zn declined during the same period. Soluble Ni possessed intermediate chemical behavior, as it appeared to be influenced both by a solid phase with pH dependent solubility and by ability to form organic complexes. Nitrification during incubations longer than 4 weeks led to a pH decline and increased Zn and Ni levels once more. Decreasing Cu levels were also associated with this period, likely due to losses of soluble organic materials via oxidation to CO2.
Mineralization of Nitrogen in Soils Amended with Organic Wastes
Authors: Chae Y. M. , Tabatabai M. A. 
Published: July 2010

AbstractThis study was conducted to compare the mineralization of N in soils amended with various sewage sludges, animal manures, and plant materials. In this work, field‐moist soils mended with organic waste materials at a rate of 50 Mg ha−1 were mixed with glass beads, packed in leaching columns, leached with 5 mM CaCl2 to remove the mineral N, and incubated at 30°C. The leaching procedure was repeated every 2 weeks for a total of 26 weeks. The leachates were analyzed for NO−3‐N. With the exception of alfalfa (Medicago sativa L.), in general, mineralization of N exhibited a slow initial rate, which was indicative of a lag period, followed by a rapid increase in rate, and subsequent slow rate of N release. The total N mineralized from the organic waste materials varied considerably, depending on the type of soil and organic waste material. The total N mineralized in five unamended soils ranged from 91 mg N kg−1 with Lester soil to 337 mg N kg−1 with Webster soil. The amounts of N mineralized in soils amended with sewage sludges and animal manures ranged from 156 to 668 mg N kg−1 soil and from 176 to 617 mg N kg−1 soil, respectively. The total N mineralized in soils amended with plant materials ranged from 0 in 3 soils amended with sawdust to 983 mg N kg−1 for Webster soil amended with alfalfa. Expressed as a percentage of total organic N added to soils, the N mineralized ranged from 1 to 58% for sewage sludges and from 13 to 67% for animal manures. The percentage of organic N mineralized in plant materials ranged from 3% for soybeans to 97% for alfalfa. Addition of corn residue or sawdust resulted in decreases in N mineralization ranging from 3 to 687%. Soil types have marked effects on the mineralizable N (No) pools and firstorder rate constants (k).
Competitive Adsorption of Heavy Metals by Soils
Authors: Elliott H. A. , Liberati M. R. , Huang C. P. 
Published: July 2010

AbstractThe competitive adsorption of Cd, Cu, Pb, and Zn from 0.025 M NaClO4 solutions onto four soils with differing chemical properties was investigated with batch adsorption experiments. For two mineral soils, adsorption under acidic conditions (pH 5.0) followed the sequence Pb > Cu > Zn > Cd, which corresponds to the order of increasing pK for the first hydrolysis product (e.g., PhOH+) of the metal ions. In contrast, the order of selectivity for two soils containing 20 to 40 g kg−1 organic C was Pb > Cu > Cd > Zn, suggesting that organic matter (OM) increased Cd retention preferentially over that of Zn. When accompanied by a sizable reduction in cation exchange capacity (CEC), extraction of soil OM markedly reduced adsorption of all four metals. However, only Cd and Cu adsorption were appreciably smaller for a soil that maintained a sizable CEC following OM removal. Lead, and possibly Zn, adsorption by soils with substantial inorganic exchange sites may be unresponsive to organic waste amendments. For Cd and Cu, increased soil OM should restrict mobility and bioavailability, at least under acidic conditions where soluble metal complex formation is limited.
Fate of Thiobencarb and Molinate in Rice Fields
Authors: Ross L. J. , Sava R. J. 
Published: July 2010

AbstractThe fate of thiobencarb (S‐[4‐chlorobenzyl] N,N‐diethylthiolcarbamate) and molinate (S‐ethyl hexahydro‐1 H‐azepine‐1‐carbothioate) in air, water, soil, and vegetation of rice (Oriza sativa L.) fields was documented for 32 d following application. Analysis of variance was used to determine if holding periods facilitated herbicide dissipation in water prior to release to drainage canals. Maximum thiobencarb concentrations in air, water, soil, and vegetation were 1.4 µg/m3, 576 µg/L, 3860 µg/kg, and 1750 µg/kg, respectively. During the 6‐d holding period, thiobencarb concentrations in water did not decline significantly, indicating that this period was not sufficient to facilitate dissipation. The mass balance budget indicated that thiobencarb was predominantly distributed between water (34%) and soil (43%) and <1% was located in air and vegetation. Maximum molinate concentrations in air, water, soil, and vegetation were 48 µg/m3, 3430 µg/L, 2210 µg/kg, and 918 µg/kg, respectively. Molinate concentrations in water declined significantly during the holding period, indicating that this water‐management practice facilitated dissipation of molinate. The mass balance budget indicated that as much as 81% of the molinate applied was dissolved in water followed by soil (10%), air (9%), and vegetation (<1%). Partitioning of these herbicides in the field was closely related to their physico‐chemical properties.
Nutrient Uptake and Growth Responses of Virginia Pine to Elevated Atmospheric Carbon Dioxide
Authors: Luxmoore R. J. , O'Neill E. G. , Ells J. M. , Rogers H. H. 
Published: July 2010

AbstractOne‐year‐old Virginia pine (Pinus virginiana Mill.) seedlings with native or Pisolithus tinctorius mycorrhizal associations were grown in pots with soil low in organic matter and in cation exchange capacity and were exposed to one of five atmospheric CO2 levels in the range of 340 to 940 µL/L in open‐top field chambers. The mean dry weight of the seedlings increased from 4.4 to 11.0 g/plant during the 122‐d exposure period. Significant increases in dry weight and uptake of N, Ca, Al, Fe, Zn, and Sr occurred with CO2 enrichment. Greater chemical uptake was associated with greater root weight. Specific absorption rates for chemicals (uptake per gram of root per day) were generally not affected by CO2 enrichment. The uptake of P and K was not increased with elevated CO2, and these elements showed the greater nutrient‐use efficiency (C gain per element uptake). The nutrient‐use efficiency for N and Ca was not influenced by atmospheric CO2 enrichment. Large increases in Zn uptake at high CO2 suggested an increase in rhizosphere acidification, which may have resulted from the release of protons from the roots, since it was estimated that cation uptake increasingly exceeded anion uptake with CO2 enrichment. Potassium, P, and NO−3 concentrations in the pot leachate decreased with higher CO2 levels, and a similar trend was found for Al and Mg. These results suggest that soil‐plant systems may exhibit increased nutrient and chemical retention at elevated atmospheric CO2.
Determination of Alkyllead Salts in Runoff, Soils, and Street Dusts Containing High Levels of Lead
Authors: Blais J. S. , Marshall W. D. 
Published: July 2010

AbstractThe determination of aikyllead salts in environmental samples that contain high levels of inorganic Pb is difficult because of poor recoveries and the formation of artifacts during the isolation and derivatization procedures. A modified procedure has been developed in which alkyllead salts are selectively extracted complexometricaliy from samples which contain up to 1000 mg Pb2+ kg−1. The extracts are butylated and analyzed by gas chromatography‐atomic absorption spectroscopy. Re‐extraction of the sample with methyl isobutyl ketone‐dithizone permits the recovery of Pb2+. This procedure was applied to rainwater runoff, soils, and street dusts from urban environments. Ethyllead salts but not methyllead salts were detected in all samples. Concentrations of these analytes were significantly correlated (P <0.01) with levels of extractable Pb2+ in these samples but not with total Pb.
Identification of Water Quality Differences in Nevada Through Index Application
Authors: Miller W. W. , Joung H. M. , Mahannah C. N. , Garrett J. R. 
Published: July 2010

AbstractThe assessment of periodic changes in water quality and uniform control standards application has been difficult to attain. A potential solution to this problem is the utilization of water quality indices for preliminary screening of data and identification of geographic areas, chronological periods, and possible source and cause of water quality changes. The purpose of this investigation was to demonstrate a practical use and application of a water quality index in Nevada as an existing option for those who must assess water quality changes on a continual basis. The study examined water quality trends in portions of the Colorado, Humboldt, Snake, Walker, and Carson River Basins, Nevada, through application of an existing water quality index to historical data from control point and adjacent monitoring stations. Index ratings were responsive in characterizing changes in water quality status relative to seasonal trends and geographic location. Identification of average annual and single value control criteria violation in terms of which parameter and degree of violation was facilitated through index application. Frequency and magnitude of impact on overall water quality status was also identified. Future use of indices in this manner should prove a valuable tool in meeting legislative water quality management strategies.
Nitrate Leaching Through Sandy Soil as Affected by Sprinkler Irrigation Management
Authors: Hergert Gary W. 
Published: July 2010

AbstractNitrate‐N (NO3) leaching losses were quantified for irrigated corn (Zea mays L.) grown on a Valentine sand using a ceramic candle extraction system buried at 1.5‐m depth. Irrigation rates were 85% and 130% of evapotranspiration (ET). Total dry matter, grain yield and crop N uptake were not significantly affected by irrigation level. During the two year study average annual flow‐weighted NO3‐N concentrations in extracted soil water ranged from 28.3 to 75.2 mg NO3‐N L−1 for 0.85 and 1.3 ET irrigation levels, respectively. In 1976 the 0.85 ET treatment had 37 ha‐mm of soil water percolation and leaching of 12 kg NO3‐N. The 1.3 ET treatment lost 191 ha‐mm of percolation and 75 kg NO3‐N. In 1977 132 ha‐mm of soil water was lost by percolation and 109 kg NO3‐N ha−1 for 0.85 ET and 182 ha‐mm and 146 kg NO3‐N ha−1 for the 1.3 ET irrigation level. The higher soil water percolation and NO3‐N losses in 1977 resulted from over‐winter precipitation and early spring leaching of the previous year's residual nitrate. In‐season NO3‐N leaching was reduced by matching irrigation to ET. To effectively reduce NO3‐N leaching N fertilizer rates must match crop yield requirements to reduce soil NO3‐N carryover and irrigation scheduling must be used on sands.
Trace Element and Salt Movement in Retorted Oil Shale Disposal Sites
Authors: Stark John M. , Redente Edward F. 
Published: July 2010

AbstractThe direction and amount of salt and trace element movement within retorted shale disposal piles is a major environmental concern. This study examines the redistribution of soluble salts and trace elements (As, B, Cd, Cu, F, Fe, Mn, Mo, Na, Ni, Pb, Se, and Zn) in retorted shale test plots with different topsoil treatments 6 yr after construction. Topsoil treatments included no topsoil, no topsoil and leached with 76‐cm water, 30‐cm topsoil, 60‐cm topsoil, 90‐cm topsoil, 60‐cm topsoil and capillary barrier, and a disturbed soil control (no retorted shale). Soluble salts (especially Na salts) and F showed considerable movement both upwards and downwards in the profiles. Molybdenum showed some movement in both directions. The remaining elements showed little or no movement out of the shale layer. Increasing topsoil depths resulted in less salt or trace element movement in either direction. Use of a capillary barrier between the topsoil and retorted shale prevented upward migration of salts and trace elements. After 6 yr the exposed shale treatments (both leached and unleached) continued to have considerably higher salt and trace element contents than any other treatment. Because of limited rooting depths, deeper percolation of moisture is occurring on plots containing retorted shale than on the control plot.
Fate of Ammonium in a Gulf Coast Estuarine Sediment
Authors: Smith C. J. , De Laune R. D. 
Published: July 2010

AbstractThe loss of 15N labeled (NH4)2SO4 applied uniformly to estuarine sediment was investigated under laboratory conditions. The recovery of 15N labeled NH+4‐N in the NH+4, NO−2 + NO−3, and organic N pools was determined at depth within the sediment cores. Concentrations of NH+4‐N generally increased with depth, with largest gradients near the surface. There was significant ammonification in underlying anaerobic sediment with a consistent increase in concentration of NH+4 being observed with increasing time of incubation. Surface sediment became depleted in 15NH+4‐N with time of incubation due to nitrification. Nitrogen‐15 losses occurred in the surface layer predominately from nitrification‐denitrification of the NH+4. Net NH+4 incorporation into the organic N fraction (immobilization) was greater in the aerobic surface sediment than in the underlying anaerobic sediment. In contrast, after 70 d of incubation, anaerobic sediment partitioned 65 ± 9% of the added 15N in the inorganic NH+4‐N pool and 27 ± 7% in the organic N pool. Total 15N losses increased with time of incubation and ranged from 9 to 26% following the addition of 3, 6.5, and 17 mg 15N excess kg−1 dry sediment.
Predicting the Fate of Nonvolatile Pesticides in the Unsaturated Zone
Authors: Wagenet R. J. , Hutson J. L. 
Published: July 2010

AbstractA simulation model of the fate of nonvolatile pesticides in the unsaturated zone is reported. The model was developed from basic principles of water and solute movement under transient field conditions, and considers water flow and resulting pesticide displacement, plant extraction of water and pesticide (if quantified), and pesticide sorption and degradation during transport. The finite‐differencing procedures were developed to provide substantial flexibility of initial and boundary conditions, allowing consideration of layered soils, multiple rainfall or evapotranspirational cycles, application of chemical in wet or dry form, plant growth, and several bottom boundary conditions. Application of the model to measured field data of aldicarb [2‐methyl‐2‐methylthio)propionaldehyde O‐(methylcarbanoyl)oxime] movement indicates that the modeling approach can provide reliable and useful estimates of the mass flux of water and nonvolatile pesticide in unsaturated soil. Sensitivity of the model to variability in soil hydraulic properties and aldicarb transformation (degradation) rates is also presented.
Crop Effects from Air Pollutants in Air Exclusion Systems vs. Field Chambers
Authors: Olszyk David M. , Bytnerowicz Andrzej , Kats Gerrit , Dawson Philip J. , Wolf Joanne , Thompson C. Ray 
Published: July 2010

AbstractCrop growth and yield effects from exposure to ambient O3 were evaluated with air exclusion systems and open‐top or closed‐top field chambers. Alfalfa (Medicago sativa L.) studies with three harvests in 1983 and three in 1984 indicated that during the summer growing season, plants respond similarly to ambient O3 when exposed in air exclusion systems and inboth open‐ and closed‐top chambers. Filtering ambient O3 in general increased plant growth in both air exclusion systems and chambers. Plant growth was most similar between nonfiltered air exclusion systems chambers and outside plots, somewhat altered in opentop chambers, and greater in closed‐top chambers than the other facilities. During the fall, alfalfa growth was similar in air exclusion systems and outside plots, whereas growth was greater in open‐top chambers than in outside plots.
Biochemical Oxygen Demand of Agricultural Runoff
Authors: Schreiber J. D. , Neumaier E. E. 
Published: July 2010

AbstractUsing an electrolytic respirometer, agricultural runoff from seven crop and tillage practices were studied to determine the 5‐d biochemical oxygen demand (BOD5). Mean BOD5 concentrations for the practices ranged from 10 to 25 mg O2 L−1 as compared to 4 to 56 mg O2 L−1 for individual storm events. In general, there was no difference in BOD5 concentrations between conventional and no‐till practices. Biochemical oxygen demand‐time relationships were found to best fit a first‐order reaction equation. The aqueous phase was the dominant source of BOD5, amounting to 64 ± 17% (1 SD) of the total BOD5 in runoff from notill soybeans, double‐cropped with winter wheat (Triticum aestivum L.). However, additional data indicate that conventional tillage practices, producing higher sediment concentrations, may result in a greater proportion of the BOD associated with the sediment phase.
Mineralization and Volatilization of Polychlorinated Biphenyls in Sludge‐amended Soils
Authors: Fairbanks B. C. , O'Connor G. A. , Smith S. E. 
Published: July 2010

AbstractPolychlorinated biphenyls (PCBs) are toxic organics of concern limiting the reuse of sewage sludge on agricultural lands. The mineralization and volatilization of PCBs (14C‐Aroclor 1254) were monitored for 240 d in three calcareous soils from New Mexico, amended or unamended with sewage sludge. Two first‐order rate constants were used to describe both processes and to compare treatment effects of sludge addition, PCB concentration (5, 50, 500 mg/kg), soil textural class, and length of sludge incubation with soils prior to experimentation. Total loss of PCBs ranged from 8 to 33%. Fifty and 95% disappearance times ranged from 2.5 to 5.9 yr and 6.1 to 26.3 yr, respectively. Treatment effects on total loss closely paralleled those of volatilization. Volatilization of organics ranged from 5 to 31%, and was the major means of loss of 14C in unamended soils and all 500 mg PCB/kg treatments. Volatilization, and thus environmental transport, was decreased by sludge addition. Exposure of the soil to sludge prior to experimentation had no effect on volatilization when compared to fresh sludge additions. Carbon‐14‐organic volatile loss was greater in two sandy loams than in a clay soil. Comparing PCB concentrations, volatilization was generally greatest at 50 mg/kg and least at 500 mg/kg, with comparatively smaller differences between 5 and 50 mg/kg. Degradation of 14C‐Aroclor 1254 to 14CO2 ranged from 1 to 11%. Overall, 14CO2 evolution, and thus detoxification increased with sewage sludge addition and decreased with increasing PCB concentration. Mineralization exceeded volatilization in sludge‐amended soils at 5 mg PCBs/kg. During the first 60 d of incubation, previous exposure of the soil to sewage sludge increased mineralization in the 5 and 50 mg PCB/kg treatments. In no case did sewage sludge additions increase the environmental hazard of Aroclor 1254 in these soils.
Decomposition of Fresh and Anaerobically Digested Plant Biomass in Soil
Authors: Moorhead K. K. , Graetz D. A. , Reddy K. R. 
Published: July 2010

AbstractUsing water hyacinth [Eichhornia crassipes (Mart.) Solms] for wastewater renovation produces biomass that must be disposed of. This biomass may be anaerobically digested to produce CH4 or added to soil directly as an amendment. In this study, fresh and anaerobically digested water hyacinth biomass, with either low or high N tissue content, were added to soil to evaluate C and N mineralization characteristics. The plant biomass was labeled with 15N before digestion. The fresh plant biomass and digested biomass sludge were freeze‐dried and ground to pass a 0.84‐mm sieve. The materials were thoroughly mixed with a Kindrick fine sand (Arenic Paleudults) at a rate of 5 g kg−1 soil and incubated for 90 d at 27 °C at a moisture content adjusted to 0.01 MPa. Decomposition was evaluated by CO2 evolution and 15N mineralization. After 90 d, approximately 20% of the added C of the digested sludges had evolved as CO2 compared to 39 and 50% of the added C of the fresh plant biomass with a low and high N content, respectively. First‐order kinetics were used to describe decomposition stages. Mineralization of organic 15N to 15NO™3‐N accounted for 8% of applied N for both digested sludges at 90 d. Nitrogen mineralization accounted for 3 and 33% of the applied organic N for fresh plant biomass with a low and high N content, respectively.