bluuebunny/crossref_metadata_2025_split huggingface dataset:
Form and Availability of Copper and Zinc in a Rhodic Paleudult Following Long‐Term CuSO4 and ZnSO4 Applications
Authors: Mullins G. L. , Martens D. C. , Gettier S. W. , Miller W. P. 
Published: July 2010

AbstractCopper and zinc frequently are incorporated into agricultural soils as fertilizers, pesticides, and waste materials. Field data are needed to determine rates of cumulative Cu and Zn applications that cause yield decreases or accumulations of the micronutrients in plant tissue. This 15‐year field experiment was conducted on a Davidson silty clay (clayey, kaolinitic, thermic Rhodic Paleudult) to determine tolerable levels of Cu and Zn applications for corn (Zea mays L.) and to evaluate soil distribution and form of the applied Cu and Zn. Neither corn grain nor silage yields were affected by 15 years of applications of various levels of Cu and Zn sulfates, which provided a cumulative total of 171.7 kg Cu/ha and 290.4 kg Zn/ha. Copper concentrations in ear leaves sampled at the early silk growth stage generally were unaffected by the Cu applications, whereas Zn concentrations in the ear leaves varied directly with levels of Zn application. Likewise, the Cu concentrations in corn grain were unaffected by the Cu applications, but the Zn concentrations in corn grain were increased by the Zn applications. The DTPA‐extractable Cu and Zn in soils sampled in the 13th year of the study indicated an accumulation of Cu and Zn in the Ap horizon, with little downward movement of the applied Cu and Zn. Sequential extraction data indicated that the applied Cu and Zn were distributed among both potentially plant‐available and ‐unavailable soil fractions.
Spatial and Temporal Patterns of Lead Accumulation in the Forest Floor in the Northeastern United States
Authors: Johnson A. H. , Siccama T. G. , Friedland A. J. 
Published: July 2010

AbstractIn light of the relatively large amounts of anthropogenic Pb deposition from the atmosphere, a regional study of forest floor Pb was undertaken. The current Pb content averages 1.1 ± 0.1 g m−2 and 148 ± 5 µg g−1 of forest floor. Factors that control forest floor Pb levels include precipitation rate, distance from the urban corridor, elevation, proximity to Pb‐emitting industries, forest floor age, and nature of the underlying mineral horizon. Analysis of buried organic horizons from windthrow mounds indicates that the Pb content of the forest floor may have increased five‐ to 10‐fold in the past century.
Application of Sewage Sludge to Soils High in Organic Matter
Authors: King Larry D. , Dunlop Willard R. 
Published: July 2010

AbstractIn a greenhouse study corn (Zea mays L.) was grown in four soils (1.4, 19, 38, and 72% organic matter) that received sewage sludge from Philadelphia, Pa., (PS) at rates to supply 0, 2, 4, and 8 kg Cd/ha. Corn and soybeans (Glycine max. L.) were grown in 1.4 and 19% organic matter (OM) soils that received sewage sludge from Wilmington, N.C., (WS) at rates to supply 0, 2, 4, and 6 kg Cd/ha. The pH of the 1.4% OM soil was adjusted to 6.5 with CaCO3. The higher OM‐content soils received recommended rates of CaCO3 to increase the pH to 5.0–5.5, the desired range for crop production on these soils. Actual resulting pH values were 5.5, 4.9, and 4.6 for the 19, 38, and 72% OM soils respectively.Corn yields were depressed by PS but enhanced by WS. Soybean yield was enhanced by WS on the 19% OM soil but depressed on the 1.4% OM soils. Both sludges caused increases in concentrations of Cd, Cu, and Zn in the plant tissue, but concentrations were not high enough to be responsible for the observed yield depressions. The PS was more effective in raising Cd and Zn concentrations in plant tissues than was WS. The type of soil had a varying effect on metal concentrations in the plants. The expected reduction in heavy metal uptake with higher soil OM content was confounded by the low pH of the soils with high OM content. The large quantity of OM added via WS masked the effect of soil OM.Since the bulk densities of the soils varied from 0.45 to 1.35 g/cm3, regression equations describing Cd concentration in corn stover as a function of OM and cation exchange capacity (CEC) were more precise when OM and CEC were expressed on a volume basis and when OM was determined by a procedure designed to estimate humus rather than total oxidizable OM.
The Effect of Cattle Grazing on Nutrient Losses in a Pacific Northwest Setting
Authors: Jawson M. D. , Elliott L. F. , Saxton K. E. , Fortier D. H. 
Published: July 2010

AbstractNutrient deliveries in runoff from a cattle‐grazed and a nongrazed (check) watershed were measured for 3 years in the Pacific Northwest to determine nutrient contributions from each. Few runoff events occurred when animals were grazing during the 3‐year study, since this is a winter‐precipitation‐summer‐grazing area.Total nitogen (TN) losses in runoff from the grazed watershed for water years 1977, 1978, and 1979 ranged from < 1 to 4 kg ha−1 year−1. During the same period TN losses from the check area were < 0.5 kg ha−1. Generally, TN received in precipitation was equal to or greater than N lost in runoff from the grazed watershed. Nitrate‐N levels in the runoff were normally < 1 mg L−1. Total phosphorus (TP) losses in runoff from the grazed watershed during water years 1977, 1978, and 1979 ranged from 0.1 to 1.3 kg ha−1 year−1 and from < 0.1 to 0.17 kg ha−1 year−1 from the check area for the same period. Though grazing appeared to cause an increase in TN, TP, total organic carbon (TOC), chemical oxygen demand (COD), and chloride (Cl) losses in runoff, the quantities would not seem to be a significant threat to downstream water.
Evaluation of Sampling Methods for Detecting Aflatoxin Contamination in Small Test Plots of Maize Inoculated With Aspergillus flavus
Authors: Widstrom N. W. , Wilson D. M. , Mc Millian W. W. 
Published: July 2010

AbstractTwo commercial maize (Zea mays L.) hybrids were grown in 1978 and 1980 to evaluate 13 sampling methods (grain‐sampling‐inoculation combinations) for formation of aflatoxin by Aspergillus flavus Link. The effectiveness of each method in producing uniform, consistent, genotype‐differentiating levels of aflatoxin was determined. Differences in level of aflatoxin contamination did not occur between years, but were highly significant between hybrids and among evaluation methods. Interactions among years, hybrids, and evaluation methods were nonsignificant. Mid‐ear inoculations with a knife at 20 d after full silk were more effective than were needle inoculations at the ear‐tip in eliciting high and consistent aflatoxin levels. Kernels from the immediate inoculated area of the ear or from inoculated segments of ears had the highest levels of aflatoxin contamination. Kernels from entire ears, or portions of ears, that appeared clean of fungus infection contained lower levels of aflatoxin contamination. Kernels from entire ears contained low to intermediate levels of aflatoxin, but the differences in levels seem adequate for detecting differences between genotypes. Treatments with low aflatoxin levels were generally associated with the highest coefficients of variation, although variances per se could not be positively associated with aflatoxin concentrations of the various methods.
Soil Adsorption of Cadmium From Solutions Containing Organic Ligands
Authors: Elliott H. A. , Denneny C. M. 
Published: July 2010

AbstractThe adsorption of cadmium (Cd) from aqueous solutions containing acetate (Ac), oxalate (Ox), nitrilotriacetate (NTA) and ethylenediaminetetraacetate (EDTA) onto three soils from the northeastern United States was investigated. Experimental parameters were adjusted so that, under typical field pH conditions, roughly half of the soluble Cd was present as Cd2+ while the other half, depending on the system, existed as Cd2+, CdAc+, CdOx0, CdNTA−, or CdEDTA2−, Organic complexation reduced, or had little perceptible effect on, Cd adsorption when compared to the unbound Cd system. In general, the ability to reduce Cd retention followed the trend: EDTA > NTA > Ox ≈ Ac. Since the strength of the Cd‐ligand stability constants follows the same order, it suggests that competition for the metal ion between the soil exchange sites and the added organic ligands is important in explaining the observed behavior. Despite the formation of cationic complexes (CdAc+), the presence of Ac interfered with Cd uptake under acidic conditions. This was apparently due to competitive adsorption of the free un‐ionized acetate species on the soil surface. The ability of organic complexants to influence Cd adsorption decreased with increasing suspension acidity because of preferential binding of the ligands to metals (Fe3+ and Al3+) released by the acid‐catalyzed dissolution of soil components. The coexistence of soluble metal chelators with heavy metals in a land‐applied waste may increase the mobility of the metals in the soil, the effect being more pronounced in neutral or alkaline soils and for ligands that form stable, nonadsorbing complexes with the metals.
Humic Substances in Landfill Leachates: I. Humic Acid Extraction and Identification
Authors: Artiola‐Fortuny Juan , Fuller Wallace H. 
Published: July 2010

AbstractA useful extraction for humic acid from anaerobic municipal solid‐waste landfill leachate is presented. Extraction was accomplished by adding NaOH pellets to give a 0.57N NaOH solution under an N2 atmosphere. The separation of the humid and fulvic acid fractions was carried out using Matricel type filters (0.45‐µm pore size diam). The infrared characterization of leachate humic acids was markedly improved in time and sample‐size‐requirement reductions by using a Matricel filter made out of a PVC copolymer as a support for these acids. The results obtained compared very favorably with the infrared KBr pellets. The infrared spectra of leachate humic acids proved to be similar to the lake‐ooze humic acid spectra reported by Stevenson and Goh (1971).Humid substances represent > 60% of the total organic C found in anaerobic landfill leachates. Fulvic acid predominates in young unstable leachates, and decreases in concentration with age. Humic acids increase with the age of the leachates, eventually decreasing as the leachate becomes more stable and diluted.
Plant Availability of Phosphorus and Heavy Metals in Soils Amended with Chemically Treated Sewage Sludge
Authors: Gestring W. D. , Jarrell W. M. 
Published: July 2010

AbstractThe objective of this study was to evaluate the effect of sludge chemical treatment (Al3+, Fe3+, and Ca2+) on P and heavy metal availability in sludge‐amended soils.Municipal sewage sludge treated with the chemicals Al2(SO4)3, FeCl3, or Ca(OH)2, along with untreated sludge and monocalciumphosphate (MCP; Ca(H2PO4)2·H2O) fertilizer, were applied to acid, neutral, and alkaline soils at rates equivalent to 83, 125, 250, and 500 kg P ha−. Swiss chard (Beta vulgaris) was grown in these soils to maturity with leaf samples taken 38, 54, and 70 d after planting. Swiss chard yields were determined and plant tissue analyzed for P, Zn, Fe, Mn, Cd, Ni, and Pb. Soil samples were analyzed for HCO3‐extractable P and pH.Zinc and Manganese concentrations in plant tissue were significantly higher (P <0.05) for the Al‐treated sludge at an application rate of 500 kg P ha−1 in the acid soil. Plant Cd levels were significantly higher (P <0.01) for the Al‐treated sludge at application rates of 250 and 500 kg P ha−1 in the acid soil. The increased plant levels of Zn, Mn, and Cd appear to be the result of a lower soil pH produced upon the addition of Al‐treated sludge. No significant differences in Fe, Ni, and Pb concentrations were observed in the plant tissue for any of the treatments or application rates.Bicarbonate‐extractable P was greater where MCP was applied than where any sludge was applied in the acid and alkaline soils; however, no discernible trends in P uptake by the chard were observed for any of the fertilizer treatments or application rates. Phosphorus was equally available from the sludges and MCP in the acid and alkaline soils.
Relationships Among Injury, Growth, and Yield Responses of Soybean Cultivars Exposed to Ozone at Different Light Intensities
Authors: Heagle Allen S. , Letchworth Michael B. 
Published: July 2010

AbstractFour soybean cultivars (Glycine max (L.) Merr. cv. Forrest, Davis, Ransom, and Bragg) differing in foliar sensitivity and shoot weight response to O3 during vegetative growth were exposed to O3 from the seedling stage to maturity to determine if the yield response correlated with the vegetative response. Neither the foliar injury nor the vegetative shoot weight response of cultivars to O3 allowed reasonable prediction of the cultivar yield response to O3. This inadequacy may relate to differences in cultivar tolerance. Bragg, with moderate amounts of O3‐induced injury and with decreased growth, yielded as well as the controls. Davis, with moderate amounts of O3‐induced injury and decreased growth, yielded 34% less than the controls. The four cultivars were grown in open‐top field chambers with different degrees of shading to determine whether light intensity would alter their response to O3. Light intensity in nonshaded open‐top chambers was 9% less than that in an open field; chambers with shade cloth covering the sides or tops decreased light intensity by 15 and 19%, respectively. The shade treatments did not change overall yield response to O3 or the relative cultivar yield response to O3.
Cadmium‐Enriched Sewage Sludge Application to Acid and Calcareous Soils: Effect on Soil and Nutrition of Lettuce, Corn, Tomato, and Swiss Chard
Authors: Mahler R. J. , Bingham F. T. , Page A. L. , Ryan J. A. 
Published: July 2010

AbstractEight soils with pH values ranging from 4.8 to 7.8 were amended at a 1% rate with a municipal sewage sludge containing variable amounts of CdSO4. The resultant concentrations of Cd in the soils ranged from 0.1 to 160 µg Cd/g. To observe the interactive effects of soil pH and Cd on elemental composition of plants, lettuce (Lactuca sativa var. Longifolia), tomato (Lycopersicon esculentum Mill.), sweet corn (Zea mays L.), and Swiss chard (Beta vulgaris var. cicla) were grown for 7 weeks in a greenhouse in pots containing the treated soils. Comparison of Cd availability to lettuce, Swiss chard, corn, and tomato grown on acid soils with that on calcareous soils revealed less Cd uptake by plants under alkaline soil conditions.The concentrations of Cd in the saturation extracts of the calcareous soil groups were significantly greater than those of the acid soil groups; however, this was not reflected in greater plant uptake of Cd from the calcareous soils.Cadmium additions to the soils generally decreased Zn and Mn concentrations in saturation extracts in calcareous soils. These decreases were reflected in reduced concentrations of Zn and Mn in leaves of the test crops. The relationships between saturation‐extract compositions of Cd, Zn, and Mn and their plant compositions were found to be different for the acid as compared with the calcareous soil groups.
The Extent and Nature of Rainfall‐soil Interaction in the Release of Soluble Chemicals to Runoff
Authors: Ahuja L. R. , Lehman O. R. 
Published: July 2010

AbstractExperiments were conducted with a simulated rainfall on boxes of three different soils (Ruston fine sandy loam, Ruston loam, and Parsons clay), prewetted with a bromide (4,000 ppm Br) solution. The bottom of the soil boxes (100 cm long by 15 cm wide by 10 cm deep) was either an impervious plate that allowed no downward infiltration through the soil during the rainfall, a pervious plate that allowed free infiltration, or a pervious plate covered with a thin layer of soil‐slurry, which allowed infiltration at a reduced level. In all the soils, Br concentrations in runoff from impervious‐base boxes were one to two orders of magnitude higher than in runoff from pervious‐base boxes. The concentrations in slurry‐base boxes were intermediate. This result and the shape of the concentration‐time curves showed that the concept of an effective complete mixing depth of rainwater and soil solution used in modeling the release of chemicals‐to‐runoff is not strictly valid. However, the concept may be applied as an approximation to the data from pervious boxes. Bromide concentrations of the soil in the impervious‐base boxes at the end of 1‐h rainfall events (6.8 cm of rain) showed that the Br was lost to runoff from as great as the 2.0‐cm depth. The amount released, however, decreased with depth. It is suggested that the transfer of chemical from below a thin soil surface layer may be due to pumping action of, or turbulence generated by, the raindrop impacts, and may be considered as an accelerated‐diffusion process. As a simplified approach, the mixing zone concept was modified and tested by incorporating an exponential decrease in the degree of mixing with depth, and a piston displacement of soil solution by infiltration. This approach seemed adequate as a first‐order approximation. The results suggest that clay‐pan soils, wet areas in a watershed, and tillage practices that increase permeability of the soil‐surface layer relative to that of the layer below will greatly increase the loss of soil chemicals to runoff.
The Impact of an Urban‐Industrial Area on Deciduous Forest Tree Growth
Authors: Mc Clenahen J. R. 
Published: July 2010

AbstractFactors affecting the height‐growth of white ash (Fraxinus americana L.) and northern red oak (Quercus rubra L.) trees in natural stands were studied within the airshed of an industrial city in central Ohio. Stepdown multiple regression analysis was used to determine the effect of tree age, topography, precipitation, and physical and chemical soil properties on cumulative height‐growth between 1930–76, which included an era of major urban and industrial expansion. Expressions of distance from the city and an index of relative pollutant exposure (RPE), derived in part from the frequency of airflow from the city during the growing season, were also tested as independent variables indicative of relative pollutant dose. Eleven and thirteen significant variables in the final white ash and red oak models explained 63 and 93% of the variation in height‐growth, respectively. Distance from the city and RPE were significant in the models of both species. Significant interactions of these variables with tree age indicated that growth of youngered oaks was more strongly depressed by increasing RPE than was that of older trees; growth of younger, but not older, white ash increased with distance from the city. Red oak growth was unexplainably predicted to be greater nearer the city. Holding tree age and site variables at their means, height‐growth was estimated by the regression models for actual RPE at selected distances and directions around the city. Isopleths constructed from these estimates showed an area of reduced growth northeast of the city in the prevailing wind direction for both species. It appears from this study that height‐growth of forest trees can be measurably depressed as a result of urban influences probably relating to air pollutant exposure.
Adsorption and Degradation of Phenol at Low Concentrations in Soil
Authors: Scott H. D. , Wolf D. C. , Lavy T. L. 
Published: July 2010

AbstractThe adsorption and microbial degradation of labile organic chemicals by soil may be influenced by their concentrations in solution. The objectives of this study were to determine the effects of relatively low concentrations of phenol on its adsorption by soil surfaces and degradation by microorganisms, and the variability associated with the adsorption and degradation by two soils. Phenol, an antimicrobial agent at higher concentrations, was equilibrated with Captina (Typic Fragiudult) and Palouse (Ultic Haploxeroll) silt loams at concentrations ranging between 10−6 (94 µg/kg) and 10−9M (94 ng/kg) and at equilibration times ranging to 24 h.Microbial degradation of phenol increased both the sampling variability and the apparent amount adsorbed by the two soils. For sterile soil the adsorbed concentration, S, was more variable than the solution concentration, C, For nonsterile soil, the variability of both S and C increased, with C more variable than S. Microbial decomposition of phenol caused the Freundlich K values to increase to a maximum at 12 h of equilibration. Little or no effect was found on the Freundlich N. Degradation coefficients were higher, and as a result, half‐lives were shorter in the Captina soil than in the Palouse. These results showed that K and N of phenol in nonsterile soil could be estimated by extrapolation to time zero.
Soluble Reactive Phosphorus Measurements in Lake Water: Evidence for Molybdate‐enhanced Hydrolysis
Authors: Tarapchak Stephen J. 
Published: July 2010

AbstractMeasurements of ortho‐phosphate (PO4‐P) concentrations in natural waters obtained by molybdenum blue methodology are based on the assumption that molybdate (Mo) complexes only with PO4‐P (in the absence of arsenate and silicate interference) to form the reductant‐sensitive complex 12‐molybdophosphoric acid (12‐MPA). The hypothesis that Mo causes or accelerates PO4‐P release from bound sources or forms reductant‐sensitive complexes with organic compounds (organic‐PO4‐Mo) was tested by exposing filtered Lake Michigan water to acid, acid plus Mo simultaneously, and Mo, respectively, before measuring PO4‐P by the Chamberlain‐Shapiro extraction method. Not only does Mo accelerate hydrolysis in the presence of acid, but it also either causes hydrolysis or forms organic‐PO4‐Mo before samples are acidified. Although the relative amounts of 12‐MPA and organic‐PO4‐Mo formed in lake water cannot be assessed quantitatively, a major fraction of the blue color formed during routine analysis by this or by similar methods apparently is not the product of acid hydrolysis, but may also be due to reduction of organic‐PO4‐Mo. Future developments in molybdenum blue methodology aimed at minimizing hydrolysis must consider the sequence of reagent additions and Mo, as well as acid, contact times.
Acid Rain and Soil Microbial Activity: Effects and Their Mechanisms
Authors: Killham K. , Firestone M. K. , Mc Coll J. G. 
Published: July 2010

AbstractIn this investigation, our aim was to determine if acid rain affects soil microbial activity and to identify possible mechanisms of observed effects. A Sierran forest soil (pit 6.4) planted with Ponderosa pine seedlings was exposed to simulated rain (pH 2.0, 3.0, 4.0, and 5.6) with ionic composition reflecting that found in northern California, corresponding to 15 cm of precipitation over a 12‐week period. After exposure, the soils were collected in two samples (top 1 cm and 4 to 5 cm), which were assayed separately for respiration and enzyme activities (urease, phosphatase, dehydrogenase, and arylsulfatase). Changes in microbial activity were most significant in surface soils. Only the pH 2.0 input caused inhibition of both respiration and enzyme activities. The overall microbial response to the pH 3.0 and 4.0 acid regimes was one of stimulation, although the response of individual enzymes was more varied. In surface soils receiving the pH 3.0 input, for example, urease activity was unaffected while arylsulfatase and phosphatase were increased and decreased respectively. Therefore, individual microbial processes will have different sensitivities to acid rain. Although changes in C‐availability in the exposed soils are documented, changes in the supply of N are evaluated as the major mechanism through which simulated acid rain affects soil microbial activity.