bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toxicity of Alkyllead Salts to Anaerobic Nitrogen Transformations in Sediment
Authors: Blais Jean Simon , Marshall William D. , Knowles Roger 
Published: July 2010

AbstractFour alkyllead chlorides (Me3PbCl, Me2PbCl2, Et3PbCl, Et2PbCl2; Me = CH3, Et = C2H5) were separately tested (at 0.1, 1.0, 5.0, and 10.0 µg L−1) for their inhibitory properties against denitrification and N2 fixation in a lake sediment as determined by acetylene blockage and acetylene reduction techniques. In the presence of added nitrate, glucose, and acetylene, alkyllead salts only moderately inhibited nitrous oxide, ethylene, and carbon dioxide accumulation by whole slurry incubations. These effects were more pronounced in supernatant from sediment. In general, ethylleads were more toxic than methyllead salts and dialkylleads were more inhibitory than their trialkyl homologs to these transformations. Successive incubations indicated that microbes adapted to the presence of these toxicants, a phenomenon also observed with other heavy metals. At the highest concentrations, which have been reported in sediments, no serious hazard to N transformations exists.
Seasonal Trends of Aluminum Chemistry in a Second‐Order Massachusetts Stream
Authors: McAvoy Drew C. 
Published: July 2010

AbstractAn investigation of streamwater chemistry was conducted to evaluate seasonal and spatial variations of Al in an acid‐sensitive watershed. Monthly grab samples were collected from three stream sites along the West Wachusett Brook, MA, and analyzed for all major solutes from March 1985 to January 1986. Total monomeric Al concentrations were greatest during high runoff periods with values as high as 22 and 11 µM in upland and wetland runoff, respectively. Survey results also illustrated the importance of ionic solute concentrations to the mobility and transport of Al. The mountain stream showed that basic cation dilution was an important factor contributing to greater Al transport during high flow periods. In contrast, organic acids in the wetland stream served as a mobile anion, and thus greatly affected Al transport by complexation and charge balance effects. Solubility with an aluminum hydroxide mineral phase did not appear to be a controlling factor of streamwater Al concentrations throughout the year. Results from a chemical equilibrium model showed the mountain stream to be potentially toxic to fish during high‐flow periods, whereas the wetland stream, being dominated by organo‐Al complexes, had a minimal potential for toxicological effects.
Fate of Trifluralin and Triallate Applied as a Mixture to a Wheat Field
Authors: Grover R. , Smith A. E. , Shewchuk S. R. , Cessna A.J. , Hunter J.H. 
Published: July 2010

AbstractDissipation of triallate [S‐(2,3,3‐trichloroallyl) diisopropylthiocarbamate] and trifluralin (a,a,a‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) in air and soil was measured following their application as a pre‐emergence treatment to a wheat (Triticum aestivum L.) field. Drift losses during application and incorporation were less than 1% of the amounts applied. Air samples, collected at six heights ranging from 30 to 200 cm above the soil surface initially and then above the crop canopy following emergence during the 67 d after application, showed distinct gradients of each herbicide in the air, with the highest concentrations in samples closest to the ground. The highest flux rates for triallate and trifluralin were 4 and 3 g ha−1 h−1 during the 4‐ to 6‐h period after application, when the concentrations at 30 cm were 2500 and 1700 ng m−3, respectively. Fluxes of both herbicides decreased with time, but were dependent mainly on soil moisture conditions. The total vapor losses for the 67‐d sampling period were 17.6 and 23.7% triallate and trifluralin, respectively. About half of these losses were in the first week. There were three distinct phases in the dissipation of both herbicides from the soil. The initial rapid phase, with vapor losses as the major route (Phase I), was followed by slow and continual dissipation over the entire growing season (Phase II), with volatilization and degradation as the potential pathways of dissipation. The third phase with little or no dissipation was reflective of the Canadian winter conditions. The gross dissipation of both herbicides during Phases I and II, however, followed the first‐order rate equation, with half‐concentration time of 88 ± 7 and 99 ± 9 d for triallate and trifluralin, respectively, with volatilization as the dominant process during Phase I.
Effects of Ozone and Sulfur Dioxide on Yield of Red Clover and Timothy
Authors: Kohut Robert J. , Laurence John A. , Amundson Robert G. 
Published: July 2010

AbstractAlthough red clover (Trifolium pratense L.) and timothy (Phleum pratense L.) are important crops in the northeast, little is known about their responses to air pollution in the field. A crop of red clover and timothy was exposed to O3 and SO2, both alone and in combination, in open‐top chambers to evaluate effects on yield. Ozone treatments were charcoal‐filtered air, nonfiltered air, and nonfiltered air to which O3 was added to maintain concentrations 1.5 and 2.0 times ambient. Sulfur dioxide treatments were ambient and three levels of addition that simulated the concentrations and dynamics of exposures near point sources of the pollutant. Yield was based on the total biomass obtained in two harvests each year. Two studies were conducted in consecutive years. Sulfur dioxide had no effect on yield and there were no interactions between the pollutants in either study. In the first year, O3 produced no effects on timothy but reduced the yield of clover and, consequently, the yield of the combined species. Red clover was less prevalent in the stand in the second year and O3 had no detectable impact on the yield of clover or on total yield since the stand was dominated by the O3‐resistant timothy. The two studies indicated that effect of O3 on yield was a function of both the concentration of the pollutant and the relative O3‐sensitivity and prevalence in the stand of the component species.
Municipal Sludge for Minespoil Reclamation: I. Effects on Microbial Populations and Activity
Authors: Seaker E. M. , Sopper W. E. 
Published: July 2010

AbstractA field study of five coal surface mine sites reclaimed with sewage sludge and one site reclaimed by conventional methods (chemical fertilizer) was conducted to assess the effects of sludge amendments and time on populations of bacteria, fungi, and actinomycetes, and on microbial respiration and organic matter decomposition. The sludge‐amended sites ranged in age from 1 to 5 yr following sludge application at rates of 120 to 134 Mg ha−1 (dry wt. basis). All sites were planted to grass and legume cover. Populations of aerobic heterotrophic bacteria, fungi, and Nitrobacter, and soil respiration rate, were highest on the 1‐yr‐old site due to the high organic matter input. On the four older sites, values decreased, but remained within the ranges reported for undisturbed soils. Actinomycete populations peaked on the 3‐ and 4‐yr‐old sites, while populations of Nitrosomonas were not related to the age of the site. Decomposition rate was lowest on the 1‐yr‐old site, and increased significantly with site age. As measured by microbial populations and activity, ecosystem recovery on the sludge‐amended sites appeared to be occurring at a more rapid rate than on the fertilizer‐amended site, which after 5 yr, exhibited sparse microbial populations and low activity. The microbial populations in the sludge‐amended spoil were not adversely affected by the heavy metals applied in the sludge, when compared with populations of soil microbes reported for undisturbed soils.
Wet Deposition Estimates from Long‐Term Bulk and Event Wet‐Only Samples of Incident Precipitation and Throughfall
Authors: Richter D. D. , Lindberg S. E. 
Published: July 2010

AbstractThis report describes a 2‐yr study comparing two sampling systems that are used to measure major ionic constituents in incident precipitation and canopy throughfall: long‐term bulk sampling vs. event‐based, wet‐only sampling. Major deviations in chemical concentrations (SO2−4, NO−3, K+, Ca2+, and H+) were documented between the two sampling systems, deviations that were ion‐specific in both incident precipitation and throughfall. Differences in chemical concentrations between the two sampling systems were greater (i) during the growing than during the dormant seasons, and (ii) for incident precipitation (collected in the open) than for throughfall under chestnut oak forest (Quercus prinus L.) canopies. Nutrient‐cycling processes in forests may be misinterpreted if flux data are based solely on long‐term bulk samplers of incident precipitation and canopy throughfall. For example, comparison of bulk and wet‐only throughfall solutions suggests that when bulk samplers collect throughfall under hardwood canopies, the ability of hardwood canopies to increase pH of low pH precipitation may be overestimated.
A Pilot‐Scale Evaluation of Alum Treatments to Reduce Lake Sediment Phosphorus Release
Authors: Young Thomas C. , Collins Anthony G. , Armstrong Robert A. 
Published: July 2010

AbstractPresented is a simple mass‐balance approach to evaluating alum inactivation of sediment‐bound phosphorus (P) using continuous‐flow reactors and aerobic sediments from a eutrophic luke (Black Lake, NY). The method permitted tests of treatment effects on the rate and duration of sediment P release, was simple to interpret, statistically reliable, and could be applied to other eutrophic systems. Analyzed as a zero‐order process, sediment P release rate decreased linearly as a function of alum dose, and the maximum dose tested (equivalent to 1.22 g Al m−2) halved the zero‐order P release rate for four hydraulic retention periods.
Spatial Variability of Phosphate Adsorption Parameters
Authors: van der Zee S. E. A. T. M. , Nederlof M. M. , van Riemsdijk W. H. , de Haan F. A. M. 
Published: July 2010

AbstractReversible phosphate (designated P) adsorption for acid soils with a narrow pH range is described with the Langmuir kinetics equation. Using a combination of two experimental desorption techniques, i.e., desorption in water and desorption in the presence of an “infinite” sink for P, respectively, the adsorption maximum (Qm) and the adsorption constant (K) were assessed for soils (pre‐)saturated with P. The adsorption maximum was proportional with the sum of oxalate‐extractable Fe and Al (ME) (i.e., Qm ≈ 0.135 ME), for topsoil samples from a field and a watershed. The K values found for the field and for the watershed samples were in the same order of magnitude (K = 15−25 L mmoL−1). The adsorption maximum and the adsorption constant, as well as the amounts of P desorbed, were spatial variates. The distributions were fitted to the normal as well as the lognormal distribution at the significance level of 0.05, using the Kolmogorov‐Smirnov test statistic.
Phosphorus and Potassium Relationships in Southwestern Virginia Coal‐Mine Spoils
Authors: Howard J. L. , Amos D. F. , Daniels W. L. 
Published: July 2010

AbstractNutrient deficiencies are commonly reported as a major limiting factor in reclaiming Appalachian surface‐mine spoils. Our objective was to intensively study the P and K relationships of representative mine spoils and contiguous natural soils derived from the Wise Formation in southwestern Virginia. Quantity/intensity (Q/I) relationships for P and K were developed for the major occurring spoils and representative natural soil materials. Sandstones (sublitharenites) and siltstones dominate the Wise Formation and show three phases of cementation—an initial carbonate phase, a second goethite phase, and a third silica overgrowth phase. Total P ranged from 255 to 530 mg/kg in the dominant sandstone and siltstone spoil types, and the majority of P was associated with complex carbonates. Phosphorus in the weathered natural soil materials was dominantly associated with Fe oxides. Phosphorus Q/I analyses coupled with P fractionation data indicate that fixation by Fe oxides is the most likely cause of P deficiencies in rock spoils derived from the Wise Formation and may be a widespread problem limiting revegetation and reclamation success in the Appalachian region. This problem is difficult to rectify by fertilization; hence, Fe oxide‐rich strata, and spoils derived from them, should be avoided during regrading to optimize surface mine reclamation. Micas and traces of feldspars are the dominant sources of K in the mine spoils. Potassium fixation by weathered mica occurs in natural soils derived from the Wise Formation, but not in unweathered spoils. Nonferruginous rock substitutes for topsoil are therefore superior as a plant growth medium in regard to P and K availability.
Desorption of Atrazine and Cyanazine from Soil
Authors: Clay S. A. , Allmaras R. R. , Koskinen W. C. , Wyse D. L. 
Published: July 2010

AbstractRemoval of soluble soil organic carbon (SSOC) during herbicide desorption studies using the batch equilibration method may affect the herbicide‐soil‐solution equilibrium particularly if herbicide‐SSOC complexes can form. Desorption characteristics of atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine) and cyanazine (2‐{[4‐chloro‐6‐(ethylamino)‐s‐triazine‐2‐yl]amino}‐2‐methylpropionitrile] were determined in a Ves clay loam (Aquic Hapludolls). For adsorption, the soil was equilibrated with 0.01 M CaCl2 solutions containing atrazine or cyanazine. Desorption with 0.01 M CaCl2 each day for 5 d resulted in hysteresis when compared to the adsorption isotherm. Replacement of the equilibration solution with soil extract for 5 d, while maintaining a higher SSOC content in the desorption equilibration solution than did the CaCl2 solution, did not change desorption isotherm equations. The SSOC‐herbicide complexes were not detected in any of the adsorption and desorption equilibration solutions by ultrafiltration (membranes with molecular mass cut offs of 10 000 and 500 daltons), HPLC, or TLC techniques. Either s‐triazine‐SSOC complexes were not formed in sufficient quantities or they were not stable enough to affect desorption of the herbicide during batch equilibration.
Dissolved Oxygen Requirements for the Indirect Photolysis Treatment of Two Refractory Herbicides
Authors: Watts Richard J. , Adams V. Dean , Middlebrooks E. Joe 
Published: July 2010

AbstractIndirect photolysis in lagoons under solar radiation has been proposed for the treatment of pesticide‐laden agricultural runoff, pesticide container rinsate, and industrial wastes. A common indirect photolysis mechanism, singlet oxygen generation, consumes oxygen through electrophilic attack on the organic waste components. Photolysis lagoons will require optimum oxygen input to achieve economical treatment. Dissolved oxygen requirements were investigated for the photolysis of bromacil (5‐bromo‐3‐sec‐butyl‐6‐methyluracil) sensitized by methylene blue and terbacil (3‐tert‐butyl‐5‐chloro‐6‐methyluracil) sensitized by riboflavin. Indirect photolysis rate as a function of dissolved oxygen residual followed saturation curves. Methylene blue‐sensitized photolysis of bromacil reached maximum rate at 1 to 2 mg L−1 O2 and the maximum rate of riboflavin‐sensitized photolysis of terbacil was reached at approximately 5 mg L−1 O2. Dissolved oxygen uptake rates for the indirect photolysis reactions correlated with electrophilic attack of singlet oxygen on the substrates. Aeration requirements for indirect photolysis treatment systems may be calculated based on the criteria presented.
Streamflow Nutrient Dynamics on Coastal Plain Watersheds
Authors: Lowrance Richard , Leonard Ralph A. 
Published: July 2010

AbstractStreamflow and water quality parameters were measured on five watersheds (262 ha‐11 487 ha) of the Little River in the coastal plain near Tifton, GA. Concentrations of nitrate, ammonium, chloride, ortho‐P, total P, total N, and electrical conductivity were determined. Loads and flow‐weighted concentrations were calculated for the five watersheds and for six subwatersheds formed by subtraction of smaller watersheds from larger ones. Mean concentrations and total loads calculated from samples taken every 3 h were not significantly different from samples taken every 12 h on two watersheds. In general, nitrate was enriched and chloride diluted relative to baseflow during storm events. This was attributed to reduction of nitrate in soils and aquifers of riparian areas. Both nitrate loads and concentrations were decreased during low flow years, whereas chloride concentrations were significantly higher in a year with abnormally low flows. Ortho‐P concentrations increased during storm events, but total P showed the opposite response. Enrichment of NO3‐N and ortho‐P and dilution of Cl and conductivity were due, in part, to concentrations in rainfall. Nutrient loads on the 11 watersheds and subwatersheds were similar except for one subwatershed that had the lowest percent of cropland but the highest loads. These high loads were due to exceptionally high flow rates in 1983 and 1984 following clear cutting of forest on nearly 25% of the subwatershed in late 1982. Nutrient loads in Streamflow were not correlated with the percent of land in spring‐planted row crops but were correlated with land in winter wheat, which is fertilized in late fall or early winter. Conditions that change hydrologic responses of watersheds may change the nonpoint sources of nutrients by changing water volumes and by altering processes that create nutrient concentrations in Streamflow.
Phosphate Uptake by Microbial Assemblages: Model Requirements and Evaluation of Experimental Methods
Authors: Tarapchak Stephen J. , Herche Lynn R. 
Published: July 2010

AbstractA “compound” Michaelis‐Menten model provides a conceptual framework for analyzing substrate‐dependent phosphate (P) uptake by natural microbial assemblages. Phosphate uptake can be separated into three substrate domains: a region near ambient P concentrations, an intermediate region, and a high‐substrate region representing substrate saturation of microbial uptake sites. Simulated P uptake for hypothetical microbial communities, ranging from non‐phosphorus‐limited to multiple‐nutrient‐limited communities, shows that (i) commonly used “high‐level” P addition schemes will underestimate community uptake rates near natural ambient P concentrations in phosphorus‐stressed systems by at least an order of magnitude, and (ii) deviations from the simple Michaelis‐Menten model may be widespread in nature, particularly in highly phosphorus‐stressed or multiple‐nutrient‐limited systems. A P uptake experiment on a natural microbial assemblage from a phosphorus‐limited oligotrophic lake illustrates application of the compound model and statistical procedures for analyzing data. An empirical procedure, based on the concept of substrate‐dependent continuity in P uptake, is proposed to determine if P addition schemes are adequate to estimate uptake constants near ambient lakewater P concentrations.
Pitch × Loblolly Pine Growth in Organically Amended Mine Soils
Authors: Moss S. A. , Burger J. A. , Daniels W. L. 
Published: July 2010

AbstractSoils on the mountainous terrain of southwestern Virginia are difficult to recover and replace before and after surface mining for coal. For this reason, combinations of soil, weathered rock, and blasted, unweathered rock are authorized as topsoil substitutes. If treated and amended properly, topsoil substitutes might be made even more productive for tree growth than the original soil disturbed by mining. Accordingly, the benefits of added municipal sewage sludge, sawdust, and inorganic fertilizer were assessed. Seven surface treatments were applied to 2:1 sandstone/siltstone overburden on a reclaimed coal surface mine in Wise County Virginia: fertilizer (168, 147, and 139 kg/ha of N, P, and K, respectively); limed (7.8 Mg/ha), and fertilized topsoil (30 cm deep); fertilized sawdust (112 Mg/ha) + 336 kg/ha slow‐release N (SRN); and lime‐treated municipal sewage sludge at rates of 22, 56, 112, and 224 Mg/ha. Stem volumes of 3‐yr‐old pitch × loblolly pines (Pinus rigida Mill. × P. taeda L.) were five times larger in soils amended with sawdust + SRN and nearly three times larger in soils amended with 22 and 56 Mg/ha sludge than fertilized‐only seedlings. Soil moisture retention was two times higher in sawdust‐amended soils than in all other treatments and contributed to increased seedling growth. Increased seedling mortality and decreased growth due to severe Mn deficiencies and/or high soluble salt levels was observed in the 112 and 224 Mg/ha sludge treatments.
Acid Precipitation Effects on Growth and Yield Responses of Twenty Soybean and Twelve Snap Bean Cultivars
Authors: Reddy M. R. 
Published: July 2010

AbstractGreenhouse studies were conducted to determine the effects of simulated acid precipitation on growth, yield, and nutrient content of soybean [Glycine max (L.) Merr.] and snap bean (Phaseolus vulgaris L.). Twenty cultivars of soybean and twelve cultivars of snap bean were grown in pots and treated with simulated precipitation at pH 2.5, 3.5, 4.5, or 5.6 (control). Soybean and snap bean plants were treated with simulated precipitation once a week beginning until fruit maturity. Soybean plants showed leaf scorching and yellowing of leaves at pH 2.5 and 3.5, whereas snap bean did not show any visible symptoms. Soybean and snap bean cultivars responded differently to acid precipitation treatments. ‘McNair 700’ and ‘Pioneer 5482’ soybean and ‘Commodore’ bush and ‘Provider’ bush snap bean cultivars yields were decreased significantly under acid treatments. Eighteen soybean and 10 snap bean cultivars were unaffected. In general, acid precipitation treatments resulted in a greater number of soybean pods without seed compared to the control. Treatments at pH 3.5 and 2.5 affected soybean and snap bean growth and yield more than the other pH levels. Potassium content of soybean shoot decreased significantly under acid precipitation treatments, whereas Ca, Mg, and micronutrient contents were not affected by low pH treatment. Nutrient content of snap bean was unaffected by acidity.
Delivery of Nonpoint‐Source Phosphorus from Cultivated Mucklands to Lake Ontario
Authors: Longabucco Patricia , Rafferty Michael R. 
Published: July 2010

AbstractCultivated mucklands (Histosols) in western New York State were investigated as a nonpoint source of P to Lake Ontario. The 70 500‐ha Oak Orchard Creek watershed, which contains 3250 ha of heavily fertilized muck cropland, was monitored at several sites for a year in order to construct a P budget for the system and determine the mucklands' relative contribution. Runoff during the late winter‐early spring period appears to be the most important hydrologic factor in governing annual phosphorus loading from the mucklands, greater than either total precipitation or total runoff for the year. Surplus P leached from muckland soils and delivered to the creek in subsurface runoff accounts for the large dissolved P load measured in the creek at the study site draining the muck cropland. At this stream monitoring location, the mucklands represented only 27% of the drainage area, but were estimated to contribute between 55 and 86% of the annual dissolved reactive P (DRP) load. The load from Oak Orchard Creek to Lake Ontario for the study period was 37 000 kg of total P (TP), 20 000 kg of which was DRP. Half of the P load was delivered to Lake Ontario in 3 months—March, April, and May—when rain and snowmelt produced significant runoff and high creek flows. A mass balance calculation suggests that as much as 72% of the DRP load and 39% of the TP load entering Lake Ontario from Oak Orchard Creek could be attributed to P losses from the cultivated mucklands located 65 km upstream.