bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sulfometuron Persistence and Movement in Soil and Water in North Dakota
Authors: Lym Rodney G. , Swenson Orval R. 
Published: July 2010

AbstractThe lateral movement, soil persistence and aqueous hydrolysis of sulfometuron [2‐([{[(4,6‐dimethyl‐2‐pyrimidinyl)amino]carbonyl]} amino]sulfonyl)‐benzoic acid] was evaluated. Sulfometuron applied at 140 g a.i. ha−1 from slopes to nontarget areas was minimal and was not detected in the 0‐to‐30‐cm‐soil depth, when sampled up to 120 cm downslope from the treated area on 2, 8, or 16% slopes 1 yr after treatment. The highest sulfometuron concentration found downslope from the treated area was less than 1 µg kg−1 regardless of the slope. Sulfometuron moved beyond the soil column (70 cm deep) in Fairdale loam [fine‐loamy, mixed (calcareous), frigid, Mollic Udifluvents], Felor silty clay loam (fine‐loamy, mixed, Typic Agriborolls), and Barnes stony loam (fine‐loamy, mixed, Udic Haploborolls) soils when leached with 45.7 cm of water for 48 h compared to only 35 to 50 cm deep when leached with the same amount of water over 9 wk. Solfometuron degradation increased as soil temperature and moisture increased. Sulfometuron was detected for an average of 429 d in Felor silty clay loam at pH 6.1, 8°C, and 45% field capacity but only 218 d in the same soil at 90% field capacity and 16°C. Degradation was slower in Renshaw and Sioux sandy loam [(undifferentiated soil mixture) fine‐loamy over sandy or sandy skeletal, mixed Udic Haploborolls and sandy‐skeletal, mixed Udortheutic Haploborolls] with a pH of 7.4 and averaged >700 d, regardless of environmental conditions. Sulfometuron hydrolysis was similar regardless of solution pH with an average of 63% 14C‐sulfometuron remaining after 28 d in water at pH 5, 7, and 9. The average halflife of 14C‐sulfometuron was 31 and 65 d in ultraviolet‐irradiated and dark control samples, respectively.
Reduction of Nitrate in Aquifer Microcosms by Carbon Additions
Authors: Obenhuber Donald C. , Lowrance Richard 
Published: July 2010

AbstractAquifer microcosms were used to examine the effects of NO−3 and C amendments on groundwater from the Claiborne aquifer. Nitrate concentrations of 12.17 mg L−1 in aquifer microcosms were reduced 0.92%/d to 5.84 mg L−1 by the addition of 10 mg C L−1 for 35 d. Nitrate disappearance correlated with increases in number of denitrifiers and dissolved N2O concentration and decreases in dissolved oxygen, suggesting biological denitrification. Nitrate/chloride ratios decreased in microcosms with 10 mg C L−1 added and then increased when the C addition was removed. Carbon additions of 0.4 mg C L−1 had no effect on the microbial or chemical properties of the microcosms. Nitrous oxide levels in wells sampling the Claiborne aquifer showed an increase with depth, indicating N2O production within the aquifer. Microcosms are useful tools to examine biological transformations of chemical contaminants in unconsolidated aquifer material. The remediation of NO−3 contaminated aquifers by organic infusion is possible and appears to be a function of microbial denitrification.
Coal Waste Reclamation using Automated Weathering to Predict Lime Requirement
Authors: Gitt M. J. , Dollhopf D. J. 
Published: July 2010

AbstractAbandoned coal waste exhibits adverse physical and chemical properties which preclude vegetation establishment. Coal waste from a site in Montana was acidic (pH 2.8), black, 85% coarse fragments and had a low water holding capacity. Incorporation of cement kiln dust (CaO) and limestone (CaCO3) to 35 cm at rates recommended by a weathering procedure neutralized coal waste acidity in the surface 10 cm. Incorporating CaO to 100 cm neutralized coal waste to the 30‐cm depth. Seeded vegetation was healthy and vigorous where lime was applied, though percent canopy cover and aboveground production were low after 2 yr. Application of kiln dust five times the recommended rate significantly reduced plant performance. Application of coversoil significantly increased plant performance compared to sites without coversoil by providing a more suitable germination medium. Increasing coversoil application from 15 to 30 cm did not significantly increase plant performance. Depth of root penetration was a function of depth of lime incorporation and coversoil thickness. Root distribution was neither confined to nor concentrated in the coversoil. Root proliferation into limed coal waste was similar to that present in overlying coversoil.
Lysimeter Study of Nitrogen Fertilizer and Irrigation Rates on Quality of Recharge Water and Corn Yield
Authors: Prunty Lyle , Montgomery B.R. 
Published: July 2010

AbstractAccrual of NO3‐N to groundwater as a result of agricultural practices is a focus of environmental concern. This inquiry was conducted to quantify precisely in a replicated experiment the rate of N loading to groundwater resulting from inputs of N and irrigation water to corn (Zea mays L.). Input levels were designed to balance potential for high production with minimum loading of NO3‐N to groundwater. Four large (2.4 by 2.4 m and 2.3 m deep) drainage lysimeters with reconstructed Hecla loamy fine sand (Aquic Haploborolls) were employed in this southeast North Dakota study. Grain yields at N fertilizer rates of 95 and 145 kg/ha were 10.3 and 11.3 Mg/ha, respectively. Differences in yield due to irrigation and irrigation by N interaction were nonsignificant. There was no residual effect of N fertilizer on yield. The higher irrigation rate caused increases in drainage of water within about 30 d. The higher rate of N fertilizer, however, was not reflected by increased concentration of NO3‐N in the drainage water until 325 d after application. The increased concentrations then persisted to 500 d. Flow‐weighted means of NO3‐N concentrations for this period were 8.6 and 12.3 mg/L for the low and high N rates, respectively. For this soil and climate, irrigation and N management can be tailored to produce NO3‐N concentrations below 10 mg/L with continuous corn. However, the 5:1 economic return produced by 50 kg/ha of incremental N fertilizer means that producers are unlikely to adopt the needed practices without incentives.
Site‐Specific Erosivity Evaluation of a Sierra Nevada Forested Watershed Soil
Authors: Guerrant D. G. , Miller W. W. , Mahannah C. N. , Narayanan R. 
Published: July 2010

AbstractLittle quantitative site‐specific infiltration, runoff, and erosion data for forested watershed soils of the Tahoe Basin are available. A Modular‐type rainfall simulator was used to examine these variables for the Cagwin (mixed Typic Cryopsamment) soil series. Three slope (0–15, 15–30, >30%) and four plot conditions (undisturbed with natural duff, undisturbed without natural duff, disturbed without natural duff, and disturbed with natural duff removed) were studied. Infiltration and runoff data were incorporated into a modified Philip's model whereas erosion data were incorporated into a general nonlinear model. Data sets were analyzed via nonlinear regression for slope and plot interaction. Slope had negligible effect on infiltration and runoff but had a significant effect on erosion. Plot condition had significant effects on infiltration, runoff, and erosion. Final infiltration rates ranged from 4.7 to 6.1 cm h−1, runoff ranged from 36 to 59% of the application rates, and cumulative interrill erosion ranged from 37.5 to 108.4 g m−2 for a simulated design storm of 8 to 10 cm h−1. The findings of this investigation were consistent with those of related quantitative investigations and indicate that the Cagwin soil has a low relative erosivity. Data from this study further suggest that previously applied models used to estimate potential erosion hazards of forested watershed soils may well result in over‐estimation of erosion potential.
Sediment Concentration of Interrill Runoff under Varying Soil, Ground Cover, Soil Compaction, and Freezing Regimes
Authors: Edwards Linnell M. , Burney J.R. 
Published: July 2010

AbstractSediment concentration (SC) was the focus of this study, which is part of a wider investigation into runoff volume and sediment mass. In the present study, SC of runoff was measured from three Prince Edward Island (Canada) soils (loam, sandy loam, and fine sandy loam surface texture) subjected to laboratory rainfall simulation to assess the effect of ground cover [winter rye (Secale cereale L.) or straw], subsoil compaction, and freezing (10 days' continuous freeze or daily freeze/thaw). Sediment concentration for the loam was 47 and 50% greater than the other soils. Straw cover gave SC of 23% < bare surface, and winter rye 25% < bare surface. Freezing treatment had no first‐order effect on SC but interacted with soil type and with ground cover. The loam showed 30% greater SC based on lower runoff volume with daily freeze/thaw than with continuous freeze. Freeze/thaw resulted in a 54% greater SC than continuous freeze. Freeze/thaw caused numerous surface cracks in the soil and enhanced internal drainage, thus resulting in less runoff than continuous freeze. A regression analysis of the relationship between SC and winter rye cover showed that variations in SC were dominated, 53%, by sediment mass (compared with 18% by runoff volume). Variations in rye cover were dominated, 49%, by leaf area (compared with 8% by leaf mass and 5% by root mass). Although this study found increasing SC to occur with subsurface soil compaction for all three soils, and the loam to be particularly susceptible to daily freeze/thaw, any adverse impact of these factors on erosion or erosion control was minimized with the use of winter rye or straw as ground cover.
Baseflow and Stormflow Transport of Nutrients from Mixed Agricultural Watersheds
Authors: Owens L. B. , Edwards W. M. , Keuren R. W. 
Published: July 2010

AbstractMany of the reported nutrient losses from agricultural areas, especially where artificial subsurface drainage is not present, have been from surface runoff. In unglaciated, well drained silt loams in eastcentral Ohio, a portion of the infiltrated rainfall moves through the soil returning to the surface at springs or seep areas. Such return flow often creates a constant baseflow in multi‐hectare watersheds. The purposes of this study were to compare relative water and nutrient transports via storm runoff with amounts removed in continuous baseflow and to evaluate the influence of different management practices on such transport. Baseflow and storm runoff from four watersheds with different land use practices were measured, sampled, and analyzed for these comparisons. In two watersheds, 123 and 32.1 ha in size, containing woodland, pasture, and row crops, the majority of N moved from the watersheds in the storm runoff; however, 25 to 50% of the N transport was via baseflow. Using 10‐yr averages, 5.0 and 2.8 kg/ha of mineral N were annually transported from the 123‐ha watershed via 242 and 196 mM of storm runoff and baseflow, respectively; from the 32‐ha watershed, 3.6 and 3.2 kg/ha of mineral N were annually transported via 144 and 198 mm of storm runoff and baseflow, respectively. Mineral N transport from a 28.8‐ha poor practice pasture watershed and from a 17.7‐ha wooded watershed was less than above, but the proportions in storm runoff and baseflow were similar. Although stormflow was the larger transport pathway for nutrients leaving a watershed, a sizable portion of the nutrients can be carried with the baseflow. This comparison of watersheds in an unglaciated area indicates that there is a negligible difference in the quality of water leaving an unfertilized wooded area or unfertilized pasture or a watershed that receives fertilization on 55% of its area.
Fate of Volatile and Semivolatile Organic Chemicals in Soils: Abiotic Versus Biotic Losses
Authors: Anderson Todd A. , Beauchamp John J. , Walton Barbara T. 
Published: July 2010

AbstractDisappearance of 15 volatile and semivolatile organic compounds was determined in a mixture added to two different soil types, a Captina silt loam (Typic Fragiudult) and McLaurin sandy loam (Typic Paleudults), using experimental procedures to distinguish abiotic losses from biological degradation over a 7‐d period. Losses due to volatilization were quantified and mass balances were calculated for each compound. Standard USEPA and National Institute of Occupational Health and Safety (NIOHS) methods were used for sample handling, storage, and analysis. The compounds (methyl ethyl ketone; tetrahydrofuran; chlorobenzene; benzene; chloroform; carbon tetrachloride; p‐xylene; 1,2‐dichlorobenzene; cis‐1,4‐dichloro‐2‐butene; 1,2,3‐trichloropropane; 2‐chloronaphthalene; ethylene dibromide; hexachlorobenzene; nitrobenzene; and toluene) were applied to the soil in a mixture such that the concentration of each chemical was 100 mg/kg soil (dry wt.). The headspace of the soil samples and matched sterile (autoclaved) controls, which were incubated in the dark at 20 °C in stoppered jars fitted with charcoal traps, was flushed daily to maintain aerobic conditions and to trap vapors. Apparent half‐lives for the 15 organic compounds ranged from < 2 to 11.3 d and showed good agreement with published values in the few instances where they were available. Rapid disappearance due to abiotic factors was observed for all chemicals during the 7‐d period. Although short‐term spike and recovery analyses yielded consistently reproducible recovery for all compounds, careful attempts to account for all losses, including the use of 14C‐toluene, were unsuccessful. Nonreversible sorption and preanalysis storage conditions were considered as contributors to this inability to achieve a mass balance. On the basis of these results, we strongly advise positive accounting for all test compounds and degradation products at the conclusion of studies involving volatile and semivolatile compounds.
Modeling the Influence of Sorption and Transformation on Pesticide Leaching and Persistence
Authors: Boesten J. J. T. I. , van der Linden A. M. A. 
Published: July 2010

AbstractPesticide leaching to ground water at 1 m depth and pesticide persistence in the plow layer were calculated with a mathematical model for a sandy soil continuously cropped with maize (Zea mays L.) and exposed to weather conditions in a temperate climate. The pesticide was applied in spring. In the model, water flow was described by Darcy's law and water uptake by the crop was included. Dally averages of meteorological conditions (rainfall, evapotranspiration, soil temperature) were used as input. The model assumes first‐order transformation, equilibrium sorption (Freundlich equation), and passive plant uptake. Pesticide leaching and persistence were calculated as a function of pesticide sorption (characterized by the organic‐matter/water distribution coefficient, Kom) and of transformation rate. It was found that pesticide leaching is very sensitive to both Kom and the transformation rate: changing Kom or the transformation rate by a factor of 2 changes the fraction of the dose leached typically by about a factor of 10. Pesticide persistence in the plow layer was found to be sensitive to Kom at low transformation rates and sensitive to the transformation rate at high Kom values. Additional calculations showed that autumn application results in much higher leaching of nonsorbing pesticides with short half‐lives than spring application (difference of two orders of magnitude).
Effects of Long‐Term 2,4‐D and MCPA Field Applications on the Soil Breakdown of 2,4‐D, MCPA, Mecoprop, and 2,4,5‐T
Authors: Smith A. E. , Aubin A. J. 
Published: July 2010

AbstractUnder laboratory conditions, the rates of breakdown of (14C)2,4‐D (2,4‐dichlorophenoxyacetic acid), (14C)MCPA (4‐chloro‐2‐methylphenoxyacetic acid), (144C)mecoprop (2‐[4‐chloro‐2‐methylphenoxy]propionic acid), and 2,4,5‐T (2,4‐5‐trichlorophenoxyacetic acid) in soils from Canadian prairie field plots, 6 wk after receiving the 43rd annual application of 2,4‐D formulations or the 37th annual treatment with MCPA, were compared with those in soils from untreated plots. Loss of 2,4‐D and MCPA was faster in soils that had received continuous applications with the appropriate herbicide than in soil from the control plots. There was some indication that (144C)2,4‐D was dissipated more rapidly from soils treated annually with MCPA than from the control soils, though breakdown was slower than in soil from the 2,4‐D‐treated plots. In contrast, (14C)MCPA breakdown in the 2,4‐D‐treated plots was similar to that in untreated soils. Breakdown of (14C)mecoprop and 2,4,5‐T in the 2,4‐D and MCPA‐treated soils was very similar to that in the control soils. Thus, there was no support for the phenomenon of cross‐enhancement. Forty‐eight weeks after the last herbicide applications, the field soils still maintained their ability to degrade 2,4‐D or MCPA more rapidly than soil from untreated control plots.
Separation of Gaseous and Particupate Dry Deposition of Sulfur at a Forest Edge in Denmark
Authors: Beier Claus 
Published: July 2010

AbstractThroughfall deposition of SO2−4 and Na+ to a spruce [Picea abies (L.) Karst.] forest edge in Denmark was measured during 1 yr. The deposition of both SO2−4 and Na* was highly elevated at the forest edge with Na+ showing the steepest gradient. Using Na+ as a model‐substance for the deposition of particles and assuming that 6 to 24% of the SO2−4‐deposition in throughfall inside the stand originated from particles, the relative contribution of particulate and gaseous S to the throughfall deposition at the forest edge could be estimated. The deposition of particulate S showed a strong dependence on the distance to the forest edge. Thus, particulate S contributed 25 to 100% of the net throughfall deposition under the front tree, whereas particulate S only contributed 6 to 24% inside the stand. The gaseous deposition showed a more moderate dependence on the forest edge and did not exceed the change in leaf area index.
Heavy Metal Extractability in Long‐Term Sewage Sludge and Metal Salt‐Amended Soils
Authors: Bell Paul F. , James Bruce R. , Chaney Rufus L. 
Published: July 2010

AbstractHeavy metals applied to agricultural soils as soluble salts are usually considered more plant available in the short‐term than equivalent amounts of metals applied to soil in sewage sludge. Slow soil chemical processes over several years, however, may change the forms, extractability, and bioavailability of metals. To determine the long‐term changes in forms of Cd added to a soil, Cd and other heavy metals were extracted with several solutions from a Christiana fine sandy loam (Typic Paleudult; clayey, kaolinitic, mesic) Ap horizon 8 or 9 yr after application of sewage sludge or CdCl2. Cadmium was applied at the rate of 21 kg ha−1 either as a component of sewage sludge or as CdCl2 in 1978 and 1979, respectively. In 1987, the distribution of Cd and other metals among soil fractions was operationally defined using the following selective dissolution and total metal analyses techniques: 10 mM Ca(NO3)2 (soluble); 5 mM DTPA (diethylenetriaminepentaacetate)‐10 mM CaCl2‐100 mM triethanolamine (TEA), pH 7.5 (exchangeable/organically complexed); 100 mM NH2OH·HCl‐10 mM HNO3 (pH 2) (Mn oxide bound); 100 mM NH2OH·HCl‐1M HNO3 (paracrystalline Fe oxide bound); and aqua regia dissolution (total soil metal). The percentages of total soil Zn, Mn, and Fe extracted by DTPA and Ca(NO3)2 from the sludge or salt‐amended soils were much less (<4%) than the percentages for Cd (47–60%), indicating greater potential mobility for Cd than for the other metals, regardless of the form of Cd added originally. A larger percentage of total soil Cd was extracted with the paracrystalline iron oxide fraction of the sludge‐amended soil (35%) than in the salt‐amended soil (23%). This greater apparent Cd association with Fe oxides in the sludge‐amended soil may have been due to the greater quantity of paracrystalline Fe oxides in that soil (843 vs. 616 mg Fe kg−1 for the sludge and salt‐amended soils, respectively). Compared to the sludge‐amended soil, the salt‐amended soil had a higher percentage of Cd in the soluble and exchangeable fractions (60 vs. 47%) and nearly equal percentages in the residual fraction (15%), suggesting, at the same total soil Cd concentration (5 mg kg−1 in 1987), plant‐available Cd would be greater from the salt‐amended soil. The sludge addition apparently enhanced retention of Cd in an iron oxide pool, relative to the soluble and exchangeable forms.
Dissipation of Clopyralid and Picloram in Soil and Seep Flow in the Blacklands of Texas
Authors: Bovey R. W. , Richardson C. W. 
Published: July 2010

AbstractThe dissipation, leaching and movement of clopyralid (3,6‐dichloro‐2‐pyridinecarboxylic acid) and picloram (4‐amino‐3,5,6‐trichloro‐2‐pyridinecarboxylic acid) were determined in soil and subsurface water after spray application of the herbicides to the surface of an area overlying a shallow perched water table in the Blacklands of Texas. A 1:1 mixture of the monoethanolamine salt of clopyralid and the tri‐isopropanolamine salt of picloram was applied at 0.56 kg a.i./ha each in May 1988 and June 1989 on the same area. Approximately 90 d after treatment, >99% of the clopyralid and >92% of the picloram had dissipated. Most herbicide was detected in the upper 30 cm of soil. No herbicide was detected in subsurface water from the area treated in 1988, but concentrations of <6 mg/m3 of clopyralid and <5 mg/m3 of picloram were detected in subsurface water collected 11 and 41 to 48 d after treatment in 1989.
Formation and Transport of Deethylatrazine in the Soil and Vadose Zone
Authors: Adams C. D. , Thurman E. M. 
Published: July 2010

AbstractAtrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine) and two degradation products were monitored at seven depths in the soil and vadose zone throughout the growing season in two experimental plots in which corn (Zea mays L.) was grown. The soils in these plots were a Kimo silty clay loam (clayey over loamy, montmorillonitic, mesic, Fluvaquentic Hapludoll) and a Eudora silt loam (course, silty, mixed, mesic, Fluventic Hapludoll). The purpose this field study was to identify and quantify the mobile and persistent degradation products of atrazine that comprise the input, or “source term,” to groundwater resulting from the application of atrazine to the soils. The formation of deethylatrazine (2‐amino‐4‐chloro‐6‐isopropylamino‐s‐triazine) and deisopropylatrazine (2‐amino‐4‐chloro‐6‐ethylamino‐s‐triazine) was monitored at vurious depths using suction lysimeters to determine the relative proportions at which these compounds enter the aquifer. Deethylatrazine was the major degradation product of atrazine identified in the soil water and appeared to enter the underlying aquifer at a concentration of 5.0 µg/L, which was greater than the concentration of atrazine entering the aquifer. Deisopropylatrazine also was detected in the soil water, bnt only in minor concentrations relative to atrazine and deethylatrazine. Because deethylatrazine was the major degradation product in the unsaturated zone, the deethylatrazine‐to‐atrazine ratio (DAR) may be a good indicator of transport of atrazine through the soil. The hypothesis is proposed that the DAR may be used to distinguish point‐source from nonpoint‐source contamination of an aquifer.