bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Dust Bowl of the 1930s: Analog of Greenhouse Effect in the Great Plains?
Authors: Rosenzweig Cynthia , Hillel Daniel 
Published: July 2010

AbstractFor nine sites in the southern Great Plains, the decade of the Dust Bowl was consistently warmer than the 1951 to 1980 “normal.” It also tended to be drier, but less consistently so. At four of the nine sites, the combination of consistently higher temperature and mostly lower precipitation had a cumulative effect over the 1930s, making the entire decade a period of agricultural drought as characterized by the Palmer Drought Severity Index (PDSI). Episodes of extreme drought occurred at many sites, particularly in 1934 in Nebraska. Temperature and precipitation changes predicted by two general circulation models (GCMs) at the upper range of current climate model predictions for doubled concentrations of CO2 (+4.2 °C and +4.0 °C mean global surface air temperature warming) suggest drought conditions as defined by the PDSI that are worse than those for the 1930s for all stations. Droughtiness is projected to increase overall, even when the GCM climate change scenarios produce little change or even increases in precipitation. In most instances, the mean GCM‐predicted drought conditions equal or exceed the extreme drought years of the decade. When dynamic crop growth models were run in combination with the GCM‐predicted climates, simulated wheat (Triticum aestivum L.) and corn (Zea mays L.) yields were obtained that were generally lower (∼30%) than those of simulations for the actual climate of the 1930s. The crop model simulations indicated that the predicted climate change is likely to be less detrimental to a crop such as wheat, whose main growing period is in the spring, than to a typical summer crop such as corn. The overall results of this study suggest that the Dust Bowl experience of the 1930s may be characterized as a preliminary analog of possible future climate conditions for the southern Great Plains, with the importance difference that the higher projections of GCM warming produce more severe climatic consequences than the Dust Bowl.
Establishment of Vegetation on By‐Product Gypsum Materials
Authors: Shahandeh H. , Sumner M.E. 
Published: July 2010

AbstractThe production of by‐product gypsum materials is likely to increase greatly in the future and will require storage in large stacks. Therefore, technology to cover these materials with vegetation will be required. The nutrient requirements for successful plant growth were investigated on three materials [phosphogypsum (PG) from Florida, and two flue gas desulfurization gypsums (FGDG) from Florida and Illinois] using weeping lovegrass (Eragrostic curvula) and lespedeza (Sericia lespedeza) as indicator plants. In the first greenhouse experiment, the requirements for all the essential nutrients were studied in a subtractive design using PG. Significant growth reductions were obtained with the singular elimination of all nutrients except B. Growth on the two FGDG materials was poor due to the presence of high levels of soluble salts. These materials were leached before being studied in the second experiment in which only N, P, and K were varied at constant basal rates of the other essential elements. The 100N‐50P‐150K (mg kg−1) treatment proved to be the best for total plant growth on all three gypsum materials. The results indicate that providing the proper nutrient balance is important in obtaining good growth on by‐product gypsum materials.
Unstable Wetting Fronts in Water‐Repellent Field Soils
Authors: Hendrickx J. M. H. , Dekker L. W. , Boersma O. H. 
Published: July 2010

AbstractStudy objectives are to (i) investigate the effects of a water‐repellent top layer on water flow and solute transport and (ii) examine whether unstable wetting front theories can be used to predict the occurrence of preferential flow in water‐repellent field soils. The study took place on two adjacent plots with grasscover near Ouddorp (The Netherlands)—one plot with a water‐repellent top layer, the other plot with a wettable top layer. The soil at the experimental site is a sand soil of marine origin—mesic Typic Psammaquent. We conducted three different tests to obtain experimental evidence for our hypothesis that flow through a water‐repellent soil would be unstable. An I− coloring technique showed an unstable wetting front with preferential flow paths in the water‐repellent soil; flow through the wettable soil resulted in a homogeneous, stable wetting front. The variability of the soil water contents in the water‐repellent soil was larger than in the wettable soil, indicating that flow through the water‐repellent soil was less stable. A Br− tracer experiment, under conditions of natural precipitation, revealed that solutes in the water‐repellent soil travelled faster to the groundwater than in the wettable soil. After 5 wk with 120 mm precipitation, the Br− amounts in the groundwater under the water‐repellent top layer were 6 to 13 times higher than those under the wettable top layer. These experimental results demonstrate that unstable wetting front theories can be used to predict the occurrence of preferential flow in water‐repellent field soils.
Logistic and Economic Principles in Gas Chromatography—Mass Spectrometry Use for Plant Uptake Investigations
Authors: Eiceman G.A. , Urquhart N.S. , O'Connor G.A. 
Published: July 2010

AbstractThe time and costs for gas chromatography‐mass spectrometry (GCMS) analysis of plant matter and sludge‐amended soil for organic compound residues have been organized using criteria for individual stages of analysis. The majority of time needed for analysis was found in sample pretreatment, regardless of operating conditions for the GC‐MS. Major costs for analysis resided in routine maintenance, depreciation of GC‐MS instrumentation, and labor costs. Whereas total variance is dependent upon concentration of the pollutant, precision is governed mainly by the number of field samples measured. Anticipated precision of more than 1 mg kg−1 can be achieved at an initial concentration of 15 mg kg−1 only after analysis of more than 60 field samples. Total analysis times and costs for a representative plant uptake study suggests GC‐MS can be an expensive and labor‐intensive approach to residue analysis. Findings offered in this analysis may be useful in the design of future experiments and in tempering expectations of advanced analytical instrumentation, in view of variance associated with sludge‐amended soil.
Volatilization of Fonofos, Chlorpyrifos, and Atrazine from Conventional and No‐Till Surface Soils in the Field
Authors: Whang J. M. , Schomburg C. J. , Glotfelty D. E. , Taylor A. W. 
Published: July 2010

AbstractWe measured the effect of no‐till on pesticide volatilization in a side‐by‐side comparison of volatilization rates from no‐till (NT) and conventionally tilled (CT) fields. Volatilization rates were determined using the theoretical profile shape method for 10 of the 26 d following application. Soil and mulch residues were also measured. Volatilization losses of fonofos (O‐ethyl S‐phenyl ethylphosphonodithioate) and chlorpyrifos [O,O‐diethyl O‐(3,5,6‐trichloro‐2‐pyridyl) phosphorothioate] from the NT field were two to four times volatilization losses from the CT field. As much as one‐half of the application volatilized during 26 d. Volatilization of atrazine [6‐chloro‐N‐ethyl‐N′‐(1‐methylethyl)‐ 1,3,5‐triazine‐2,4‐diamine] was also greater from NT, but only 1 to 2% of the application volatilized. Maximum volatilization rates were usually measured at midday, indicating that volatilization was not limited by soil dryness. Over the 26 d of the experiment, volatilization decreased faster than pesticide residue was depleted, suggesting residues were becoming more strongly sorbed to soil and/or mulch, or were becoming less accessible to the surface.
Sorption and Movement of Alachlor in Soil Modified by Carbon‐Rich Wastes
Authors: Guo Lei , Bicki Thomas J. , Felsot Allan S. , Hinesly Thomas D. 
Published: July 2010

AbstractLaboratory studies were conducted to determine the effects of waste‐activated carbon (WAC), digested municipal sewage sludge (DMS), and animal manure (AM) on the sorption and leaching of alachlor [2‐chloro‐2′,6′‐diethyl‐N‐(methoxymethyl)acetanilide] in a Plainfield sandy soil (Typic Udipsamment). A total of 7500 mL of simulated rain water was applied to soil columns under three flow regimes with or without the waste amendments. The WAC most effectively reduced the mobility of alachlor, DMS was superior to AM. Amounts of alachlor recovered in the leachates, which ranged from <0.1% (2.1 t C ha−1 of WAC amended soil) to 74% (unamended soil) of that applied, depended upon the C loading rate of the wastes and upon the source of C‐containing species. The dissipation of alachlor from soil was greater when soil was amended with DMS and AM than when amended with WAC. Sorption of alachlor, which was determined by batch equilibration, was generally inversely related to its leaching in the amended soil, this observation suggested that sorption by soil organic matter controlled the mobility of alachlor. Application of C‐rich wastes to sandy coarse‐textured soils may be useful for reducing pesticide leaching to groundwater.
Reclamation of Heavy Metal—Contaminated Soils: Field Studies and Germination Experiments
Authors: Geiger Gabriella , Federer P. , Sticher H. 
Published: July 2010

AbstractField studies and germination experiments have been performed to assess the fertility restoration by different reclamation procedures on heavy metal‐polluted soils. In a contaminated area in Switzerland we have investigated the metal accumulation of lettuce (Lactuca sativa L., ‘Apollo’) on four different experimental plots: F1 was untouched, F2 was plowed, on F3 the highly contaminated litter was removed, and on F4 the surface layer was removed and replaced with uncontaminated soil. The metal content in plant tissue decreased from F1 over F2 and F3 to F4. The lettuce grown on F4 had normal metal tissue concentrations (Cd, 0.92 mg/kg; Cu, 28 mg/kg; Zn, 87 mg/kg) whereas tissue concentrations on the untilled plot F1 were strongly elevated (Cd, 6.1 mg/kg; Cu, 57 mg/kg; Zn, 864 mg/kg). Growth chamber experiments served to test the suitability of different soil substrata for plant development. We have studied the germination and growth of cress (Lepidium sativum L.) and lettuce on different heavy metal‐polluted media and observed that the structure of the litter is the main reason for poor development of the seedlings. We conclude that from the reclamation procedures considered, only the replacement of the highly contaminated topsoil will lead to good germination, normal plant development, and heavy metal contents essentially below all toxicity limits.
Bioavailability of Zinc, Cadmium, and Lead in a Metal‐Contaminated Alluvial Soil
Authors: Pierzynski Gary M. , Schwab A. Paul 
Published: July 2010

AbstractMetal mining activities can cause a variety of soil contamination problems including the deposition of sediments having high concentrations of heavy metals on alluvial soils. This study was conducted to investigate the effects of various soil amendments or combinations of amendments on Zn, Cd, and Pb bioavailability in a metal‐contaminated alluvial soil as indicated by a chemical fractionation procedure and soybean [Glycine max (L.) Merr.] growth and heavy metal composition. Total soil concentrations were 1165 mg/kg for Zn, 11 mg/kg for Cd, and 110 mg/kg for Pb, and evidence suggested that Zn phytoxicity was limiting soybean growth. In one greenhouse experiment, the addition of limestone, N‐Viro soil, and K2HPO4 significantly increased soybean yields; and the addition of limestone, limestone suspension, cattle manure, poultry litter, N‐Viro, and K2HPO4 significantly decreased soybean tissue Zn concentrations as compared to the control. The limestone, limestone suspension, cattle manure, N‐Viro, and K2HPO4 amendments also significantly reduced KNO3‐extractable Zn as compared to the control. In a second greenhouse experiment, the combination of limestone at 1.12 or 2.24 Mg/ha and 10 Mg/ha of cattle manure produced significantly higher soybean yields as compared to either amendment alone for the first cutting. For the same cutting, a significant limestone by manure rate interaction was found for concentrations of Zn, Cd, and Pb in soybean tissue and for Zn, Cd, and Pb uptake. Generally, the effects of increasing limestone rate were diminished as the manure rate increased. Root dry weights significantly increased and root tissue Zn concentrations significantly decreased with both rates of limestone application compared to 0 Mg limestone/ha for samples taken at the completion of experiment two. Root tissue Cd or Pb concentrations were not significantly influenced by limestone or manure rates. Significant increases in NaOH‐extractable Zn and Pb were found with increasing limestone rates whereas NaOH‐extractable Cd significantly decreased. Correlations between soybean tissue Zn concentrations and various Zn fractions and diethylenetriaminepentaacetic acid (DTPA)‐extractable Zn indicated significant relationships for KNO3‐Zn (r = 0.92), NaOH−Zn (r = 0.62), KNO3 + H2O−Zn (r = 0.82), KNO3 + NaOH−Zn (r = 0.88), KNO3 + H2O + NaOH−Zn (r = 0.54), and DTPA extractable Zn (r = 0.70).
Physiographic and Land Use Characteristics Associated with Nitrate‐Nitrogen in Montana Groundwater
Authors: Bauder J. W. , Sinclair K. N. , Lund R. E. 
Published: July 2010

AbstractOccurrence of NO−3‐N in drinking water at concentrations > 10 mg L−1 is being reported in the literature with increasing frequency. Some occurrences of high NO−3‐N concentrations have been attributed to irrigation and fertilization practices. A private well water testing program in Montana, involving nearly 3400 well owners, found NO−3‐N concentrations > 10 mg L−1 in nearly 6% of all tested wells. Most of the agricultural land in Montana is nonirrigated and is not subject to high rates of N fertilization. Dryland crop/fallow cereal grain rotations are the main practices. Well water test results were combined with MAPS, a geographic information system (GIS), to identify correlations between county average NO−3‐N concentration in groundwater, well water sample probability of exceeding 10 mg L−1 NO−3‐N, geographic, climatic, and geologic conditions, and land‐use practices. From a list of 67 independent variables, county average well water NO−3‐N concentration and percentage of tested wells in each county with NO−3‐N concentration >10 mg L−1 were correlated (P < 0.10) with 16 independent variables, most of which were associated with precipitation, soil properties, and land‐use practices. The closest correlations were with March 1 through June 30 precipitation, distribution of dryland crop production and summer fallow, soil water‐holding capacity, and mapping units of the general soil map of Montana. Two‐, three‐, and four‐variable, linear, multiple regression models indicated that 53 to 61% of the variability in county average well sample NO−3‐N concentration could be accounted for by these independent variables. Results of these analyses support the hypothesis that summer fallow practices and associated mineralization of organic matter may be contributing to regionalized NO−3‐N contamination of shallow groundwater in Montana.
Degradation of the Pesticides Mecoprop and Atrazine in Unpolluted Sandy Aquifers
Authors: Klint Mikala , Arvin Erik , Jensen Bjørn K. 
Published: July 2010

AbstractThe potential for biodegradation of the pesticides mecoprop [(+/−)‐2‐(4‐chloro‐2‐methyl‐phenoxy)propionic acid] and atrazine [2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine] in an aerobic aquifer was investigated in laboratory batch experiments. The experiments were performed with groundwater and suspensions of groundwater and aquifer sediment collected from a pristine sandy aquifer. Following a lag period of 35 to 40 d, mecoprop in a concentration of 100 µg/L was degraded in 30 d in groundwater at 10°C. New additions of 100 to 140 µg mecoprop/L were degraded within a week. In suspensions of groundwater and aquifer sediment, mecoprop in the concentration range 75 to 300 µg/L was degraded in 15 d, following a lag period of less than 7 d. Experiments performed with sediments taken from different depths indicate that there was a considerable variation in the degradation potential within the aquifer. Atrazine was not degraded during an incubation period of 539 d in groundwater and 174 d in suspensions of groundwater and aquifer sediment. The addition of nutrients, primary substrates (acetate and naphthalene), and a pH or temperature increase had not effect on the recalcitrance of atrazine.
Groundwater Nitrate Dynamics in Grass and Poplar Vegetated Riparian Buffer Strips during the Winter
Authors: Haycock N.E. , Pinay G. 
Published: July 2010

AbstractNitate retention in riparian buffer strips is well documented in summer periods, but the potential of winter retention within these zones is poorly documented. Two sites, grass (Lolium perenne L.), and poplar (Populus italica)‐vegetated riparian strips, were investigated in southern England (River Leach). Groundwater flow was via subsurface pathways within the sites, NO−3 concentration gradients and loading rates were calculated over the winter period. Nitrate retention was found to be linearly dependent on load rate. Nitrate retention occurred at the edge of the riparian zone. This was most obvious in the poplar site where all hillslope‐derived NO−3 was absorbed within the first 5 m of flow within the riparian strip. When loading rates into the sites increased, NO−3 absorption migrated upslope from the riparian site. The poplar‐vegetated riparian zone was found to be more resilient (99% retention of NO−3) than the grass‐vegetated riparian zone (84% retention of NO−3) in the winter months. It is postulated that although vegetation has no active role in retaining NO−3 in the winter, above‐ground vegetative biomass does contribute C to the soil microbacterial biomass that is engaged in NO−3 reduction in the winter months, this accounted for the greater efficiency of the poplar vegetated site.
Cadmium, Lead, Zinc, Copper, and Nickel in Agricultural Soils of the United States of America
Authors: Holmgren G.G.S. , Meyer M.W. , Chaney R.L. , Daniels R.B. 
Published: July 2010

AbstractThree thousand forty‐five surface soil samples from 307 different soil series were analyzed for Pb, Cd, Zn, Cu, Ni, cation exchange capacity (CEC), organic C, and pH in the course of a study of trace element uptake by major agricultural crops. The soil data from this study are summarized here statistically and in map form to show their interactions and generalized geographic distribution patterns. Amounts of all five metal elements are generally low in the Southeast. A regional high of about 15 mg/kg Pb covers the Mississipi, Ohio, and Missouri River valleys. Higher values for other elements are generally concentrated in the West and in the lower Mississippi River Valley. Maximum Cd levels were found in soils of the coast ranges of central and southern California. Copper levels are noticeably higher in organic soil areas of Florida, Oregon, and the Great Lakes. Nickel and Cu concentrations are high in serpentine soil areas of California. Nickel levels are also somewhat higher in the glaciated areas of the northern great plains and in northern Maine. For the entire dataset, the values of the minimum‐maximum, 5th, 50th, and 95th percentiles are as follows: (mg/kg dry soil) Cd, <0.005 to 2.0, 0.036, 0.20, 0.78; Pb, 0.5 to 135, 4.0, 11, 23; Zn, 1.5 to 264, 8.0, 53, 126; Cu, 0.3 to 495, 3.8, 18.5, 95; Ni, 0.7 to 269, 4.1, 18.2, 57; pH (pH units) 3.9–8.9, 4.7, 6.1, 8.1; CEC (cmol/kg) 0.6 to 204, 2.4, 14.0, 135; and organic C % 0.09 to 63, 0.36, 1.05, 33.3. Metal levels generally increased with increasing clay concentration.
Oxidation and Acidification of Anaerobic Sediment‐Water Systems by Autoclaving
Authors: Tratnyek Paul G. , Wolfe N. Lee 
Published: July 2010

AbstractThe effect of autoclaving on the acid/base and redox properties of anaerobic sediment slurries was determined to facilitate the interpretation of autoclaved controls in studies of environmental reduction reactions. Autoclaving decreased electrode measurements of pH by 0.26 to 0.68 units and increased electrode measurements of Eh by 34 to 94 mV. To corroborate this effect, we added redox indicators to the slurries and observed that autoclaving caused a shift in color consistent with the change in electrode measurements. Further investigation demonstrated that the observed effects are a common characteristic of autoclaving anaerobic sediment and are not limited to very restricted sediment types and are not artifacts of the way the experiments were performed.
Biological Effects of Agriculturally Derived Surface Water Pollutants on Aquatic Systems—A Review
Authors: Cooper C. M. 
Published: July 2010

AbstractEnvironmental manipulations and other human activities are major causes of stress on natural ecosystems. Of the many sources of surface water pollutants, agricultural activities have been identified as major contributors to environmental stress, which affects all ecosystem components. In water, agricultural contaminants are most noticeable when they produce immediate, dramatic toxic effects on aquatic life although more subtle, sublethal chronic effects may be just as damaging over long periods. Aquatic systems have the ability to recover from contaminant damage if not seriously overloaded with irreversible pollutants. Thus, contaminant loading level is as important as type of pollutant. Although suspended sediment represents the largest volume of aquatic contaminant, pesticides, nutrients, and organic enrichment are also major stressors of aquatic life. Stream corridor habitat traps and processes contaminants. Loss of buffering habitat, including riparian zones, accelerates effects of pollutants and should be considered when assessing damage to aquatic life. Protection of habitat is the single most effective means of conserving biological diversity. Current available management practices and promising new technology are providing solutions to many contaminant‐related problems in aquatic systems.
Spatial Variability of Microbial Processes in Soil—A Review
Authors: Parkin T. B. 
Published: July 2010

AbstractMicrobial transformations of fertilizers and pesticides in the surface soil have a direct impact on the mass of the agrochemical that is susceptible to leaching losses. Thus, our greatest potential for controlling leaching losses of agrochemicals is through the management of these compounds in the surface soil. A variety of strategies have been employed to maximize the residence time of applied chemical in the surface soil, including: timing of application, formulation (e.g., slow‐release fertilizers and encapsulated pesticides), and the use of compounds that modify microbial activity in soil (e.g., nitrification inhibitors). Although these strategies have met with some success, more precise quantification of the microbial transformations of agrochemicals is required to aid the development of improved management strategies. The high spatial variability exhibited by many microbial processes, in many cases, precludes precise quantification. A greater understanding of the factors contributing to the variability of microbial processes allows for improved estimation, as well as for the assessment of key driving variables controlling microbial processes in soil. This article reviews several aspects of spatial variability associated with microbial populations and processes. The discussion focuses on the scale at which variability is expressed, and the soil and environmental variables that serve to control variability at each scale. Implications for the development of new management strategies are also discussed, and finally, some statistical considerations for characterizing variability are presented.