bluuebunny/crossref_metadata_2025_split huggingface dataset:
Washoff of Ultra‐Low‐Volume‐Oil‐Applied Insecticides from Cotton Plants as a Function of Time between Application and Rainfall
Authors: Willis G.H. , McDowell L.L. , Southwick L.M. , Smith S. 
Published: July 2010

AbstractModel development for predicting the movement of foliar‐applied pesticides depends on being able to characterize the dynamics of pesticide disappearance from plants, including washoff by rainfall. This study was conducted to determine the effect of elapsed time between spray application and initial rainfall on pesticide washoff from foliage. Methyl parathion [0, 0‐dimethyl,0‐(p‐nitrophenyl) phosphorothioate] and fenvalerate [(RS)‐α‐cyano‐3‐phenoxybenzyl (RS)‐2‐(4‐chlorophenyl)‐3‐methylbutyrate] were applied in oil by rotary‐atomizer controlled‐droplet applicators to mature cotton (Gossypium hirsutum L.) plants. Simulated rainfall (51 mm in 1 h) was applied to the plants at different times after insecticide application to determine washoff characteristics for both compounds. Residues of both insecticides became increasingly resistant to washoff with increasing time interval between pesticide application and initial rainfall. The mean amounts of both insecticides washed from the plants (i) were related to the square of the mean insecticide loads on the plants and (ii) decreased exponentially with time.
Bare Soil Evaporation and Solute Movement in Selenium‐Contaminated Soils of Kesterson Reservoir
Authors: Zawislanski Peter T. , Tokunaga Tetsu K. , Benson Sally M. , Oldfather Joan M. , Narasimhan T.N. 
Published: July 2010

AbstractTwo approaches were taken to estimate evaporation of water from the surface of a salt‐encrusted and Se contaminated soil in a playalike environment at Kesterson Reservoir, California. Direct evaporation flux measurements were made using a lysimetric (gravimetric) approach and revealed a seasonal dependence of bare soil evaporation rates, which ranged from 0.1 to 1.5 mm d−1. The low range is suggestive of a vapor‐flux control of bare soil evaporation due to the presence of a salt crust. Temporal changes in chloride concentrations and soil moisture content were used in a quantitative assessment of a mean seasonal evaporative flux. Bare soil evaporation rates measured by these two methods compared favorably. Although concentrations of salts and Se in near‐surface soil fluctuated seasonally during a drier than average year, a slight net decline in salt concentrations was observed over 12 mo due to rainfall infiltration and the associated solute transport. Increases in Se near the soil surface due to an evaporatively driven flux appear unlikely in this setting, due to low rates of bare soil evaporation as compared with downward fluxes due to rainfall infiltration.
Bromide Movement at Selected Sites in a Dissected Piedmont Landscape
Authors: Bathke G. R. , Cassel D. K. , McDaniel P. A. 
Published: July 2010

AbstractSoil hydraulic properties vary across landscape positions due to changes in soil profile characteristics. Water and solute transport in soils are intimately related to soil property and water balance relationships. The objectives of this study were to identify the interdependency of solute transport on hydrologic, pedologic, and geomorphic properties of a dissected Piedmont landscape and to determine soil features conducive to lateral water movement within the soil profile. Crystalline KBr was applied at a rate of 1 kg/m2 in 15 m long by 15 cm deep trenches on 11 Aug. 1987 to one linear slope (LS1) and two headslope (HS1 and HS2) positions in a clayey, kaolinitic, thermic Typic Kanhapludult soil under pasture in the Piedmont of North Carolina. Soil cores were taken on 8 Mar. 1988, 20 July 1988, and 3 Nov. 1988 in a grid of sample positions along the trench (PAT) and downslope from the trench (DFT). The highest Br− levels on 8 March were found at LS1, followed by HS2, in the B horizons at the 0.25 m DFT. Solute concentrations declined with DFT and time at every site. Differences in Br− distribution with PAT indicated that preferential movement occurred at LS1, but only to a minor extent at HS1 and HS2. The centers of mass of the Br− profiles at LS1 and HS2 were found in the upper B horizons. Bromide moved deeper at HS1, where the soil profile was formed entirely in hillslope alluvium and had the lowest clay and dithionite‐extractable iron (Fed) contents throughout the solum. The alluvial‐residual parent material discontinuity between the Bt1 and Bt2 horizon of HS2 contributed to greater lateral Br− transport compared with site LS1, where bulk density and macroporosity changed minimally and/or gradually with depth. Water and Br− transport was dominantly vertical through the soil profile at LS1.
A Field Chamber for Testing Air Pollution Effects on Mature Trees
Authors: Albaugh Timothy J. , Mowry Fred L. , Kress Lance W. 
Published: July 2010

AbstractA 3.6 m tall by 3 m diam. open‐top chamber system built on 12‐m towers for the dispensing and exclusion of air pollutants in the foliage of mature loblolly pine (Pinus taeda L.) trees was tested. Statistically significant position and height differences in O3 concentration inside the chamber were found for different wind speed categories. Calculation of a relative O3 concentration (ROC) showed remarkably similar relative O3 profiles for charcoal filtered (CF) and 2x ambient (2x) chambers. Large reductions in ROC are found above the 2.4‐m level in both chambers. Ambient air intrusion was reduced in the modified chamber because it was protected by the canopy and contained a tree crown lessening air movement in the chamber. The mean temperature increase in the chamber from 1200 to 1259 h EST was 2.2°C, whereas the maximum temperature increase was 4.8°C. Statistically significant positional temperature differences were found within the chamber. The chamber system design was found useful in testing the effects of gaseous air pollutants on the crown of mature trees and is recommended for designed experiments.
A Methodology for Establishing Phytotoxicity Criteria for Chromium, Copper, Nickel, and Zinc in Agricultural Land Application of Municipal Sewage Sludges
Authors: Chang A. C. , Granato T. C. , Page A. L. 
Published: July 2010

AbstractThis study illustrates a methodology of evaluating phytotoxicity criteria for metals, when sewage sludges are applied on cropland. The analyses are based on data available in technical literature and fundamental principles of soil fertility and plant nutrition. First, data from laboratory experiments, where plants were grown in media treated with only one metal element, were used to develop an empirical cause‐and‐effect relationship between metal concentration in plant tissue and growth retardation of plants. This relationship is used to select the phytotoxicity threshold (metal concentration of plant tissue corresponding to a given level of plant injury). Then, data from land application of sewage sludge experiments were used and soil metal loading rates were plotted against the corresponding plant tissue metal concentrations. The probability of plants, grown on soils with a given range of metal loadings, exceeding the phytotoxicity threshold may be calculated. Finally, an appropriate loading range is selected based on the risk of exceeding the phytotoxicity threshold that is considered acceptable. In this exercise, the data were extracted without imposing any bias and represent a wide range of conditions where land application of municipal sewage sludge has been practiced nationwide. The reliability of the results, however, remain dependent on the quality of the data. A great deal of information already exists in the published literature. Through this exercise, gaps in the technical data base may be identified.
An Information Management Technology Program for ex ante Nutrient Loss Reduction from Farms
Authors: Lemberg Beth , McSweeney William T. , Lanyon Les E. 
Published: July 2010

AbstractReducing nutrient losses from farms to the environment can be done before or after the nutrients have been applied to the fields. If effective best management practices can be implemented before nutrients are applied (ex ante), difficult and uncertain remedial management practices can be avoided. The relative environmental and economic consequences of an information management technology program were compared under two contrasting water resource protection perspectives by linear programming simulation of a dairy farm. The information program was based on measuring the amount of materials transferred to and from the fields as crops and manure, and the sampling and analyses of those materials. Potential N losses to the environment were reduced substantially and costs of the information management program were generally more than offset by the savings in fertilizer expenditures compared to the outcome when no credit was given to manure nutrients in the fertilization of farm crops. Exacting requirements for nutrient utilization under a restrictive water resource protection perspective resulted in only a fraction of the total manure produced being spread on the farm fields, however. The negative economic impact of this limitation was potentially much greater than the costs to implement the information management technology program. Standards for both the extent of the information required to adequately meet the environmental expectations and the acceptable range of the expectations must be established if the management practice is to be feasible and successful.
Sediment and Nutrient Loss from Clay Soils as Affected by Tillage
Authors: Chichester F. W. , Richardson C. W. 
Published: July 2010

AbstractAgricultural source pollution of water resources has been a source of concern in recent years. Research is needed to define mechanisms of chemical and sediment loss in runoff from agricultural land, and to develop management practices that minimize transport of these pollutants. This study was designed to compare the effect of no‐till (NT) and conventional chisel‐till (CT) soil management on runoff water volumes, sediment loss, and N and P loss from small watersheds on a clay soil. Three NT and three CT watersheds located on Houston Black clay vertisol soil (fine, montmorillonitic, thermic, Udic Pellusterts) in east central Texas were used for the study. Wheat (Triticum aestivum L.), corn (Zea mays L.) and sorghum [Sorghum bicolor (L.) Moench] were grown rotationally on the watersheds from 1984 to 1989. Runoff amounts, sediment loss, and N and P losses were measured for each rainfall event that produced runoff. Runoff volume was not changed by tillage system and sediment loss and N and P losses in runoff were less, on average, from NT than from CT. Runoff averaged 1.3 ML ha−1 annually for both CT and NT. Average annual quantities for sediment and nutrient losses were: 160 kg ha−1 and 1575 kg ha−1 for sediment, 3.8 kg ha−1 and 8.1 kg ha−1 for N, and 0.8 kg ha−1 and 1.5 kg ha−1 for P for NT and CT, respectively. These results indicate that the loss of sediment and nutrients from agricultural lands could be minimized by using NT on clay soils.
Evaluation of Phosphate Materials for Control of Acid Production in Pyritic Mine Overburden
Authors: Spotts Edward , Dollhopf Douglas J. 
Published: July 2010

AbstractAcid mine drainage is a serious and pervasive threat to surface and groundwater quality in the USA. Recent research has indicated that phosphate can be effective at immobilizing Fe and inhibiting the production of acid associated with the oxidation of pyritic mine wastes. Four phosphate materials were replicate tested for their ability to inhibit acid production from pyritic coal overburden using a soxhlet humidity cell leaching technique. These materials included two apatite ores (Comineo ore and Texas Gulf ore) at an application rate of 30 g kg−1 by weight apatite [Ca5(PO4)3OH] and two byproducts of the phosphate industry (Cominco waste and Stauffer sludge) at rates of 10, 30, and 50 g kg−1 apatite by weight. Results of leachate analyses indicate that all phosphate sources at all rates of application resulted in significant (P ≤ 0.05) decreases in titratable acidity vs. a control Acidity reductions ranged from a low of 7% for samples treated with Cominco waste (10 g kg−1) to a high of 67% for Texas Gulf ore‐treated samples. Texas Gulf ore, Stauffer sludge (10, 30, and 50 g kg−1) and Cominco waste (10, 30, and 50 g kg−1) significantly reduced dissolved total Fe concentrations in leachate, with Stauffer sludge (50 g kg−1) and Texas Gulf ore producing the most notable diminutions (62 and 63%, respectively). Maximum decreases in sulfate (SO2−4) concentrations of 26, 20, and 25% were achieved by applications of Texas Gulf ore and Stauffer sludge (30 and 50 g kg−1), respectively. The more effective overall performance of the Stauffer sludge and Texas Gulf ore was attributed to the considerably greater relative surface area and P solubility of these amendments. Results of a scanning electron microscope examination of amendments corroborate these findings.
Retention of Dissolved Organic Carbon and Sulfate in Aggregated Acid Forest Soils
Authors: Guggenberger Georg , Zech Wolfgang 
Published: July 2010

AbstractAdsorption of dissolved organic carbon (DOC) and sulfate was examined in mineral A and B horizons of aggregated acid forest soils from declining (Oberwarmensteinach) and healthy (Wülfersreuth) Norway spruce [Picae abies (L.) Karst.] stands in northeastern Bavaria, Germany. Adsorption studies were conducted in the laboratory on undisturbed, aggregated soil samples under nonequilibrium conditions using a miscible displacement method. Initial mass relationships suggest a net release of DOC in the A horizons of both stands at all DOC concentration levels added. In contrast, the B horizons retained DOC from solutions containing more than 4 to 5 g C m−3 in the Oberwarmensteinach B horizon, and 2 to 3 g m−3 in the Wülfersreuth B horizon, respectively. These concentrations correspond to mean annual DOC concentrations in the B horizon solutions of both sites. Addition of sulfate (1.60 molc SO4 m−3) significantly reduced DOC retention, suggesting competition between SO4 and parts of DOC for adsorption sites. Retention of sulfate from solution occurred concentrations with more than 0.38 to 0.42 molc SO4 m−3 in Oberwarmensteinach, and 0.25 to 0.31 molc SO4 m−3 in Wülfersreuth, respectively. Compared with batch experiments, the miscible displacement method resulted in lower affinities of the soils for DOC. Reduction of DOC and sulfate retention by the use of the flow‐generated technique is due to the consideration of sorption kinetics, which are influenced by soil structure and texture. Although this method underestimates the affinity of a soil for DOC to a certain extent, we suggest that it reflects the situation in the field quite well. Flow‐generated experiments showed that the decline phenomena of spruce in Oberwarmensteinach correspond with a reduced potential for DOC retention in the upper B horizon, as well as with lower sulfate retention throughout the profile.
Degradation and Transport of Dicamba in a Clay Soil
Authors: Comfort S.D. , Inskeep W.P. , Macur R.E. 
Published: July 2010

AbstractDicamba (3,6‐dichloro‐2‐methoxybenzoic acid) has been identified as one of five pesticides present in Montana groundwaters. We determined the effects of degradation and time of water application on the transport of dicamba in a Lohmiller clay soil (fine, montmorillonitic, mesic Ustic Torrifluvent). Carbon 14‐labeled dicamba was surface applied (0.35 kg ha−1) to disturbed soil columns (5.0 cm diam; 29 cm length) previously conditioned with 3 mM CaCl2. The columns were allowed to incubate (23.5 °C) in triplicate for 0, 14, 21, 28, and 42 d. Following incubation, the columns were attached to a vacuum chamber containing a fraction collector and leached with 3 mM CaCl2 under unsaturated conditions. Dicamba breakthrough curves were determined for each incubation period. The percentage of dicamba recovered in the column effluent decreased from 85% (of total applied) after no incubation to 9.5% after 42 d of incubation. The decline of dicamba in the effluent coincided with an accumulation of dichlorosalicyclic acid at the soil surface. Dicamba half‐lives determined under batch conditions were 23.5 d at 28 °C, 38 d at 20 °C, and 151 d at 12 °C, and were all higher than the half‐life estimated from the decrease in column effluent concentrations over time (13.5 d). The simulation model, LEACHM, was used to predict transport of dicamba after the different incubation periods. LEACHM adequately estimated the mass of dicamba leached, but underestimated the maximum dicamba concentrations observed in the effluent. Both simulated and observed results indicated that the transport of dicamba can be greatly reduced if sufficient degradation of dicamba is allowed to occur before irrigation or precipitation.
Tests of the Pesticide Root Zone Model and the Aggregate Model for Transport and Transformation of Aldicarb, Metolachlor, and Bromide
Authors: Parrish Rudolph S. , Smith Charles N. , Fong Fred K. 
Published: July 2010

AbstractMathematical models are widely used to predict leaching of pesticides and nutrients in agricultural systems. This work was conducted to investigate the predictive capability of the Pesticide Root Zone Model (PRZM) and the Aggregate model (AGGR) for the pesticides aldicarb [2‐methyl‐2‐(methylthio)propionaldehyde O‐(methylcarbamoyl)oxime], metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylethyl)acetamide], and for a bromide tracer. Model predictions were compared with data collected during 1984 to 1987 in the Dougherty Plain area of southwestern Georgia. Field data were used to estimate mean concentrations of pesticide and bromide residues in the soil profile on various dates after application in each of four growing seasons. Both models tended to predict rates of movement of bromide tracer compounds in excess of that observed. For metolachlor, a pesticide with a sorption‐partition coefficient that is higher than for other compounds in the study, both models provided reasonably accurate predictions within the upper 30‐cm zone. For the pesticide aldicarb, results were more variable. The results suggest that the hydrologic components of both models are more accurate for the upper zones, but they are imprecise in deeper zones, underpredicting vertical dispersion and overpredicting transport velocity.
Soil, Climate, and Atmospheric Deposition Relationships with Elemental Concentrations in Annual Rings of Tuliptree
Authors: McClenahen J. R. , Vimmerstedt J. P. 
Published: July 2010

AbstractThe objectives of this study were to investigate the relationships of contrasting soil properties, climate and atmospheric pollutant (especially S) deposition to elemental concentrations in tree rings. Concentrations of 12 elements were determined in annual rings of tuliptree (Liriodendron tulipifera L.) by proton‐induced x‐ray emission for the 50 even years from 1880 to 1980 within an urbanized‐industrial region in northeastern Ohio. Xylem concentrations of nine elements were consistently and significantly greater on Site 1 where soils were coarse textured and base status was low, than on Site 2 where soils were medium textured and base status was greater. Time series analysis detected high frequencies of elemental pulse interventions during periods of rising S emissions in the 1920s and mid‐1940s. Additionally, step changes in xylem S during these periods, and recently declining xylem S may also reflect changing S emissions. Significant climatic regressions [seasonal mean temperatures and total precipitation, plus annual basal area increment (BAI)] were obtained for 11 elements. Prior fall precipitation was the most consistent and important climate variable associated with xylem chemistry. A significant negative association of BAI with xylem Ca on Site 1, where soil Ca was low, suggested a growth dilution effect and the possibility that soil Ca may be near a critical limit. Soil properties influenced both the absolute concentrations of nearly all elements in xylem and relationships between xylem chemistry and climate. Variations in climate, in addition to soil, are therefore important considerations in spatial and temporal comparisons of xylem chemistry.
Effects of Climatic Variations over 11 Years on Nitrate‐Nitrogen Concentrations in the Raccoon River, Iowa
Authors: Lucey K. J. , Goolsby D. A. 
Published: July 2010

AbstractNitrate‐nitrogen (NO3‐N) concentrations at public water‐supply intakes on the Des Moines and Raccoon Rivers in Iowa exceeded the maximum contaminant level (MCL) of 10 mg L−1 for public water supplies established by the USEPA for extended periods of time from March through early August 1990. The excessive NO3‐N levels followed 2 yr of less than normal precipitation in 1988 and 1989. The largest daily NO3‐N load (771 t) transported during the last 17 yr in the Raccoon River occurred in June 1990. The streamflow hydrograph for the Raccoon River for March 1990 prior to seasonal fertilizer application indicates that high NO3‐N concentrations characterize the recession side of the hydrograph. High NO3‐N concentrations in streamflow persisted as streamflow decreased to baseflow conditions. This implies that substantial quantities of NO3‐N were being leached from the soil and transported by subsurface flow during early 1990. A multiple linear‐regression model was developed to predict NO3‐N concentrations in the Raccoon River from readily‐obtainable streamflow and climatic data. The four‐variable model explained about 70% of the variability in the concentration of NO3‐N. The mean streamflow for the previous 7‐d period accounted for about 50% of the total variability.
Designing Septic Tank Filter Fields Based on Effluent Storage during Climatic Stress
Authors: Rutledge E. M. , Teppen B. J. , Mote C. R. , Wolf D. C. 
Published: July 2010

AbstractSeptic tank filter fields (FFs) in many soils undergo seasonal hydraulic failure due to climatic stress. We investigated the hydraulic behavior of an experimental FT with a 61 cm wide, 9.0 m long, and 76 cm deep bed constructed in a loamy‐skeletal, siliceous, mesic, Typic Fragiudult with a perched seasonal water table. The true water table was estimated to be deeper than 30 m. The FF was loaded with 15 L m−2 d−1 of septic tank effluent and monitored for 5 yr. At times each year, in response to rainfall, effluent rose within the bed to near the soil surface and spread laterally into the adjoining soil. This effluent was “stored” until climatic stress ceased. The experimental FF stored an estimated 20 d of effluent input; 220 L (14%) could be stored in the bed and 1410 L (86%) in the soil adjacent to the bed. Hydraulic stress events were the design‐limiting periods for FF loading. The experimental FF operated without detection of surfaced effluent for 5 yr, so 20 d of storage was chosen as the design goal for evaluating FF designs in this soil. The loading rate for noninteracting beds was inversely proportional to bed width, so the most efficient FFs should consist of narrow beds. When 61 cm wide beds were placed closer together than 5.9 m center‐to‐center, their storage volumes began to interact and loading rates had to be reduced accordingly. This approach to FF design for soils with perched seasonal water tables suggests that loading rates be determined either by effluent storage or by the rate of effluent movement out of the beds, whichever is most limiting.