bluuebunny/crossref_metadata_2025_split huggingface dataset:
Long‐Term Swine Lagoon Effluent Applications on ‘Coastal’ Bermudagrass: I. Yield, Quality, and Element Removal
Authors: Burns J. C. , King L. D. , Westerman P. W. 
Published: July 2010

AbstractSwine (Sus scrofa domesticus) confinement systems that use anaerobic lagoons for waste collection in the humid regions require effluent removal during the year. Land area adjacent to the hog facility frequently becomes the site for continuous effluent distribution. The objective of this experiment was to determine the effect of long‐term application of swine lagoon effluent to ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] on dry matter yield, stand persistence, and nutrient concentration and removal. Effluent loading rates of low (L), medium (M), and high (H) approximating 335, 670, and 1340 kg of N ha−1 yr−1, respectively, were evaluated for 11 yr beginning in 1973 through 1983. The experiment was a randomized complete block with three replicates. Dry matter yields in Year 11 were altered by effluent loading rates with greater production from the M (19.0 Mg ha−1) or H (19.6 Mg ha−1) compared with the L (13.1 Mg ha−1). Although fluxes in stands occurred, they recovered completely as indicated by these yields. Higher concentrations of N, P, K, Mg, Cl, and Zn were present in forage in 1983 compared with 1973. Calcium was unchanged and Cu, Fe, and Na were less. In vitro dry matter disappearance of the forage was similar among loading rates (0.634) in 1983 and greater than in 1973 (0.553). Concentrations of NO3‐N were higher in 1978 (1.14 g kg−1) compared with 1973 (0.87 g kg−1), but highest concentrations occurred in 1983 (1.57 g kg−1). By 1983, NO3‐N concentrations of forages from the H loading rate approached or exceeded the toxic threshold in all summer harvests. Only the H loading (1340 kg ha−1) caused unstable stands and eventually produced forage that had NO3‐N concentrations potentially toxic if fed as the sole ration to ruminants. Further, it resulted in disproportionally greater quantities of elements—especially N, P, K, Cl, and Na—that remained in the soil environment to become potential soil and soil‐water pollutants.
The Effect of Deicing Salts on Trace Metal Mobility in Roadside Soils
Authors: Amrhein Christopher , Strong James E. 
Published: July 2010

AbstractCalcium magnesium acetate (CMA) (Ca0.3Mg0.7(C2H3O2)2) is being used as an alternative to NaCl for deicing highways. CMA is an effective deicer, handles well, biodegrades, is less toxic to aquatic life, and is less corrosive than Cl salts. There is some concern, however, that CMA may increase the mobility of certain trace metals from roadside soils. Roadside soils were collected from around the USA from high‐traffic and high‐salt use areas. These soils were characterized for total trace metal content as well as important chemical and physical parameters. Studies were carried out to determine (i) the effect of CMA decomposition on Pb and Cd concentrations in an aqueous system (no soil), (ii) changes in major and minor element chemistry in soils incubated with NaCl and CMA solutions, and (iii) the mobility of trace metals from soil columns leached with solutions of deicing chemicals and/or H2O. Microbial decomposition of the acetate resulted in increased pH, CaCO3 precipitation, and immobilization of Cd either through coprecipitation with CaCO3 or CdCO3 precipitation. There was no difference in trace metal solubility in soils treated with H2O or 10 mmolc L−1 CMA or NaCl (average runoff concentration). Trace metal concentrations were initially high in soils treated with 100 mmolc L−1 solutions of deicing salts but concentrations decreased with time due to adsorption or precipitation reactions. The leachability of Pb from soil columns was strongly correlated with organic matter solubilization. Soils leached with NaCl followed by distilled water had reduced permeabilities as compared to CMA‐leached soils. It appears the effect of CMA on trace metal mobility in roadside soils should generally be beneficial.
Salinity, Nitrate, and Water in Rangeland and Terraced Wheatland above Saline Seeps
Authors: Berg W. A. , Naney J. W. , Smith S. J. 
Published: July 2010

AbstractSaline seeps have emerged over the past 20 yr in some Southern Plains soils cropped annually to winter wheat (Triticum aestivum L.). Saline seep development is a cumulative process associated with percolation of small increments of water over many years through saline strata in recharge areas to build up water tables over less‐permeable strata in lower slope positions. In this study soluble salt, nitrate, and water content were determined in Woodward soils (coarse silty, mixed, thermic Typic Ustochrepts) to a depth of 3 in terraced farmland and in adjacent native rangeland upslope from saline seeps. Significantly (P<0.05) more soluble salt was present in the surface 3 m of rangeland than in adjacent farmland. No difference (P>0.05) was found in soluble salt content in farmland between terraces as compared to soluble salt in terrace channels. Greater amounts (P<0.05) of nitrate and water were in the 3‐m profiles under farmland than under native range. The soluble salt profiles indicate more water has percolated through the farmland than the rangeland. The implication is cultivated land, both in terrace channels and between terraces, is contributing salt and water to saline seep. An alternative explanation is terrace channels are the major recharge areas and lateral flow of this water leachesalt from farmland between the terraces.
Maize Production Impacts on Groundwater Quality
Authors: Schepers J. S. , Moravek M. G. , Alberts E. E. , Frank K. D. 
Published: July 2010

AbstractThe cumulative effects of management practices on nitrate‐nitrogen (NO3‐N) leaching and groundwater quality are frequently difficult to document because of the time required for expression and the diversity of interacting processes involved. This work reports results of a N and water management program initiated by the Central Platte Natural Resource District (CPNRD) in Nebraska. Cultural practices recommended by the CPNRD and reported by producers for the 1988 growing season, representing approximately 3900 fields covering 84 210 ha of irrigated corn (Zea mays L.) indicated NO3‐N contamination of groundwater was influenced by yield goals and fertilizer N application rates. Groundwater NO3‐N concentrations were positively correlated with residual N in the surface 0.9 m of soil prior to the growing season, reflecting the effects of past N and water management practices. Yield goals in 1988 averaged 9% higher than the average 10.0 Mg ha−1 corn yield attained, which accounts for an average of about 20 kg N ha−1 in excess of the average N recommendation. By comparison, in a 1980 to 1984 study from an area within the CPNRD, yield goals averaged 28% greater than actual yields. Overly optimistic yield goals in 1988 accounted for 42% of the average excess N application rate of 48 kg ha−1 (based on University of Nebraska recommendations). A large portion of average excess N application is attributed to producers in 14% of the area who applied >100 kg N ha−1 more than the recommended rates. Fertilizer N applied showed little relationship to fertilizer N recommended. Better education and more stringent measures may be required to address the select group of producers who fail to follow CPNRD recommendations.
Effects of Spatial Accumulation of Runoff on Watershed Response
Authors: Garbrecht Jurgen 
Published: July 2010

AbstractThe drainage network accumulates upstream subwatershed runoff into a single downstream response, with runoff accumulating at network junctions. The effects of this accumulation on the magnitude and spatial variability of the downstream response are reviewed for simplified boundary conditions. Runoff parameters are runoff depth and corresponding unit area peak runoff rate. At the subwatershed level these parameters are referred to as d and q, respectively, and they vary from one subwatershed to another. At a downstream location, after accumulation by the drainage network, corresponding parameters are referred to as D and Q. Equations expressing the effects of runoff accumulation are formulated and discussed for uniform rainfall conditions. The review shows that the effects of runoff accumulation gain in importance as the number of upstream subwatersheds and the size of the watershed increase in the downstream direction. The accumulation process cancels extreme values of d and q to yield a representative D and Q value for the entire upstream drainage area. The impact of individual d and q values on the downstream D and Q values in the channel diminishes as the number of upstream subwatersheds increases. This results in a decrease in the spatial variability of D and Q in the downstream direction. The review suggests that the role of spatial variability of upstream d and q in the determination of downstream D and Q diminishes as watershed size increases. However, nonuniform rainfall distributions and storm movement may overshadow the effects of runoff accumulation when watershed size increases beyond the size of the storm.
Modeling the Cumulative Watershed Effects of Forest Management Strategies
Authors: Ziemer R. R. , Lewis J. , Rice R. M. , Lisle T. E. 
Published: July 2010

AbstractThere is increasing concern over the possibility of adverse cumulative watershed effects from intensive forest management. It is impractical to address many aspects of the problem experimentally because to do so would require studying large watersheds for 100 yr or more. One such aspect is the long‐term effect of forest management strategies on erosion and sedimentation and the resultant damage to fish habitat. Is dispersing activities in time and space an effective way to minimize cumulative sedimentation effects? To address this problem, Monte Carlo simulations were conducted on four hypothetical 10 000‐ha fifth‐order forested watersheds: one watershed was left undisturbed, one was completely clearcut and roaded in 10 yr, with cutting starting at the head of the watershed and progressing toward the mouth, another was cut at the rate of 1% each year beginning at the watershed's mouth and progressing upstream, and another was cut at a rate of 1% each year, with individual cut areas being widely dispersed throughout the watershed. These cutting patterns were repeated in succeeding centuries, rebuilding one‐third of the road network every 100 yr. The parameters governing the simulations were based on recent data from coastal Oregon and northwestern California. Mass wasting, the most important source of sediment in that environment, was the only hillslope process modeled. The simulation results suggest that (i) the greatest differences between management strategies appeared in the first 100 yr and were related primarily to the rate of treatment. By the second 100 yr, when all watersheds had been treated, the principal difference between logging strategies was the timing of impacts. (ii) Dispersing harvest units did not significantly reduce cumulative effects. (iii) The frequency of bed elevation changes between 1 and 4 cm is dramatically increased by logging.
Probability of Sediment Yields from Surface Erosion on Granitic Roadfills in Idaho
Authors: Megahan Walter F. , Monsen Stephen B. , Wilson Monte D. 
Published: July 2010

AbstractA series of 29 bordered plots, 1.8 m wide by 4.6 m long, was used to measure sediment yields from granitic roadfills on forest roads in the mountains of Idaho. Slope gradients on the plots ranged from 34 to 41°. Sediment yield data for the snowfree season were collected for 3 yr following road construction. Various site factors were tested by regression analysis for their effects on sediment yield, but only ground cover density and snowfree period rainfall erosivity were statistically significant. Analysis of 22 yr of snowfree period rainfall erosivity data showed that erosivity was log‐normally distributed and established the parameters for the probability density function. These data, coupled with the prediction equation from the regression model, were then used in a Monte Carlo simulation model to define the probability of occurrence of sediment yields from granitic roadfills given various levels of ground cover density. Recently published studies that update the slope gradient and slope length components of the Universal Soil Loss Equation are used to extrapolate the results of the present study to all lengths and gradients of granitic roadfills. A discussion of the application of the study results is presented.
A Four‐Year Mobility Study of Selected Trace Elements and Heavy Metals
Authors: Sheppard Marsha I. , Thibault D. H. 
Published: July 2010

AbstractThe environmental impact of accidental or chronic releases of contaminants to the unsaturated soil zone, either through surface spills or contaminated groundwater, has become a major concern. This study was designed to provide data after 1 and 4 yr to compare the leaching and upward transport of Tc, I, Np, Cs, U, Th, Cr, and Mo in cores of the same soil in outdoor lysimeters. Over the 4‐yr study a broad range of climatic, soil moisture, and temperature conditions existed, which were representative of long‐term means as well as some extremes. The amount of rainfall leached through the cores decreased with time. The leaching resulted in a downward movement of fine soil particles, especially in the lower horizons. Element mobility in the leaching cores for the 4 yr decreased in the order I > Tc ≫ Cr > Np > Mo > Cs ≥ U > Th. This differs slightly from the ranking predicted after 1 yr. After 1 yr, Mo appeared to be more mobile than Cr or Np. After 4 yr, I, Tc, Np, and Cs migrated to the soil surface from depth. Analysis of the soil solid/liquid partition coefficient, Kd, values indicates the retention of these elements is primarily related to soil organic matter content and dependent on porewater concentration. The Kd model is appropriate for I in all soil horizons and for Tc, Np, and Cs in the Ae horizon of the groundwater cores. The Freundlich isotherm or a kinetic expression best describes the sorption for all other elements and horizons.
Mathematical Model of Plant Uptake and Translocation of Organic Chemicals: Development of the Model
Authors: Lindstrom F. T. , Boersma L. , McFarlane C. 
Published: July 2010

AbstractUptake, translocation, and accumulation of organic chemicals by plants are influenced by plant characteristics, chemical properties, and environmental conditions. Experimental evaluation of plant contamination for the many xenobiotic chemicals now in use or being developed is impractical. A mathematical model was formulated which, when adequately tested, can be used to provide information about potential contamination. The model was formulated by defining a generic plant as a set of adjacent compartments representing the major pools involved in transport and accumulation of water and solutes. The model plant is divided into root, stem, and leaves and each is subdivided into two transport compartments (xylem and phloem) and a storage compartment. Chemical uptake is modeled from the soil solution to the root surface, through the apparent free space, endodermis into the xylem and throughout the plant. Values for the anatomical dimensions of the compartments and for physical and chemical coefficients were chosen from the literature. This article shows formulation of the mass balance equations, which lead to the complete system of equations that describe uptake. The solution gives chemical mass in each compartment as a function of time. The mathematical development yielded a well‐defined concept of uptake, in‐plant transport, and local accumulation of organic chemicals by plants.
Mathematical Model of Plant Uptake and Translocations of Organic Chemicals: Application to Experiments
Authors: Boersma L. , McFarlane C. , Lindstrom F. T. 
Published: July 2010

AbstractA mathematical model for uptake of organic chemicals by plants was calibrated by application to data from experiments in which the uptake of bromacil (C6H13BrN2O2) by soybean [Glycine max (L.) Merr.] plants was measured. The plants had been exposed to a range of bromacil concentrations at several transpiration rates. The model was initially formulated by defining a generic plant as a set of adjacent compartments representing the major pools and pathways involved in transport and accumulation of water and solutes. For this application the plant consists of one root, three stem, and three leaf compartments, with each compartment being subdivided into xylem, phloem, and storage. The model was calibrated with respect to storage coefficients that quantify rate of transport to and from storage. For calibration, bromacii concentrations measured in roots, stems, and leaves were compared with model predictions, while model parameters were changed until no further improvement in matching model prediction with experiment result was obtained. This calibration exercise revealed important plant behavior demonstrating the value of the model for elucidating plant response. The model was changed during the calibration to account for specific phenomena that occur in the roots and leaves. The information obtained was applied to results from additional experiments. Storage coefficients differed substantially between roots, stems, and leaves showing differences in plant structures and physiological functions. The coefficients generally were proportional to compartment size, independent of transpiration rate except at low concentrations and independent of concentration except at high concentrations. The model satisfactorily predicted the observed uptake and distribution patterns for bromacil in soybean plants at the stage of growth and under the environmental conditions of the experiments.
Changes in Foliar Concentration of Abscisic Acid in Soybean in Response to Sulfur Dioxide Fumigation
Authors: Gupta Gian , Sandhu Ravinder , Mulchi Charles 
Published: July 2010

AbstractSoybean [Glycine max (L.) Merr.] cv. Elf plants were exposed to 0.0, 0.05, 0.2, and 0.4 µmol mol−1 SO2 in a controlled environment. The amount of abscisic acid (ABA) was measured, using an enzyme linked immunosorbent assay (ELISA), after 1, 2, or 4 h of exposure as well as after 18 h of recovery period. With 0.05 µmol mol−1 SO2, the ABA concentrations in soybean leaves were 28 and 141% higher than the control, with 1 and 4 h exposures, respectively; after an 18‐h recovery period, the ABA concentrations were still higher (23.6 and 42.8% for the 1 and 4 h exposures, respectively). Abscisic acid concentration increased in soybean leaves both with an increase in the concentration of SO2 and the time of exposure.
Foliar Absorption of Atmospheric Ammonia by Ryegrass in the Field
Authors: Sommer S. G. , Jensen E. S. 
Published: July 2010

AbstractThe dry deposition of ammonia (NH3) in the field was measured simultaneously at increasing distances from a point source (a dairy farm) using a biomonitor. The biomonitor was Italian ryegrass (Lolium multiflorum Lam) grown in pots and supplied with 15N‐labeled N. The use of 15N improved the precision and lowered the detection limit of the method compared with calculating the NH3 deposition using the difference method (N‐balance method). Atmospheric NH3‐concentrations were measured by drawing air through traps containing sulfuric acid. At the end of a 6‐wk period in the growing season, the deposition of N was 3.0 g N/m2 and 0.7 g N/m2 at average atmospheric concentrations of 89 and 6 µg NH3‐N/m3, respectively. Estimated deposition velocities ranged from 0.7 to 3.4 cm/s with an average of 1.6 cm/s (s.d. 1.2 cm/s).
Concentration‐Dependent Effects of Ozone on Translocation of Assimilates in Douglas Fir
Authors: Gorissen A. , Schelling G.C. , van Veen J.A. 
Published: July 2010

AbstractThe assessment of air quality standards for forest ecosystems requires proper knowledge about concentration‐effect relations of air pollutants for tree species. In this study, 2‐yr‐old Douglas fir seedlings [Pseudotsuga menziesii (Mirb.) Franco] were exposed to 23, 81, and 169 µg O3/m3 during 8 h/d, 5 d/wk for a period of 4 wk. After exposure, the trees were placed in an atmosphere containing 14CO2. Release of 14CO2 in the root/soil compartment was analyzed once a day and was regarded as an index of transport and utilization of 14C photosynthates. Respiratory release of 14C was temporarily inhibited by O3 during the first days following exposure to the air pollutant. Within 2 wk after the O3 treatment, 14CO2 in the root/soil respiration was the same in all treatments, indicating that trees were recovering from O3 injury.
Mechanisms for Trichloroethylene Vapor Sorption onto Soil Minerals
Authors: Ong Say Kee , Lion Leonard W. 
Published: July 2010

AbstractPartition coefficients were determined for trichloroethylene (TCE) vapor (P/Po <2% or concentration <10 mg L−1) for several minerals over a wide range of moisture contents. For oven‐dried minerals, surface area was found to be a good indicator of the sorptive capacity of the solid phase. As moisture content was increased, the partition coefficients of TCE vapor decreased by several orders of magnitude, attained a minimum, and then gradually increased. Mechanisms of TCE vapor sorption were proposed corresponding to three regions of sorbent moisture content. In Region 1, from oven‐dried conditions to one monolayer coverage of water on the solid surface, direct solid‐vapor sorption was evident with strong competition between water and TCE for adsorption sites on the sorbents. In Region 2, between a monolayer coverage to approximately five layers of water molecules, likely interactions between TCE vapor and water include sorption of TCE onto surface‐bound water and limited TCE dissolution into sorbed water with some “salting out” effects caused by water structure. In Region 3, extending from a minimum of approximately five layers of water molecules to the water retention capacity of the soil, TCE dissolution into condensed water‐dominated vapor uptake along with sorption at the water solid interface. Thermodynamic data and the development of a simple model were used to interpret the above processes. Application of Henry's Law to model TCE interaction with the soil water was possible only after five layers of water molecules have formed.
Pesticide Mobility and Persistence in Microlysimeter Soil Columns from a Tilled and No‐Tilled Plot
Authors: Fermanich K. J. , Daniel T. C. 
Published: July 2010

AbstractPesticide leaching losses under varying tillage systems, especially in sandy soils, is not clearly understood. This study compared the leaching and dissipation of two corn (Zea mays L.), 14C‐labeIed, insecticides—carbofuran (2,3‐dihydro‐2,2‐dimethyl‐7‐benzo‐furanylmethylcarbamate) and chlorpyrifos [O,O‐diethly O‐(trichloro‐2‐pyridyl) phosphorothioate]—in sandy soil columns from conventional‐moldboard plow (CN) and no‐till (NT) tillage plots. Microlysimeters, utilizing intact soil columns from established tillage plots, were used to investigate pesticide mobility and dissipation under simulated field precipitation, drainage, and temperature patterns. Leachate from CN tillage columns receiving 14C‐carbofuran contained over two times more of the applied 14C (17.9%) compared to NT columns (7.9%). The major portion (63%) of 14C‐carbofuran residues leached from CN columns was associated with a metabolite (unknown I) compared to 40% for NT columns. Slightly more (4.9% compared to 4.6%) 14C as parent carbofuran leached from CN columns relative to NT. After 106 d of simulated field conditions, 4.0 and 7.8% of the applied parent 14C‐carbofuran was recovered from the soil of CN and NT columns, respectively. Average time to peak 14C‐carbofuran residue concentrations were retarded by 12 and 39 d for CN and NT columns, respectively, compared to time to peak concentrations of bromide. Less than 0.2% of the applied 14C‐chlorpyrifos leached from the soil columns. Differences in the physical, chemical, and/or biological characteristics between CN and NT tillage columns influenced the dissipation and mobility of carbofuran.