bluuebunny/crossref_metadata_2025_split huggingface dataset:
Injury and Yield Response of Cotton to Chronic Doses of Ozone and Soil Moisture Deficit
Authors: Heagle Allen S. , Miller J. E. , Heck W. W. , Patterson R. P. 
Published: July 2010

AbstractPlant response to ozone (O3) is known to be modified by soil moisture deficit, which occurs in varying degrees during most growing seasons. Thus, we examined the response of cotton (Gossypium hirsutum L. ‘McNair 235’) to different levels of seasonal stress by O3 when grown at two soil moisture levels. The cotton was exposed for 12 h d−1 in open‐top field chambers to five O3 doses (seasonal 12 h d−1 means from 0.020 to 0.074 µL L−1) under well‐watered (WW) conditions or under water‐stressed (WS) conditions with periodic cycles of low soil moisture. Exposures began when the fifth leaves were expanding and continued for 124 d when most leaves were chlorotic or had abscised. Ozone caused significant yield loss in WW plots but not in WS plots. Based on estimates from polynomial regression analysis, ambient O3 (seasonal 12 h d−1 mean of 0.044 µL L−1) caused a yield decrease of 19% in the WW plots compared to the O3 level in our charcoal‐filtered air plots (seasonal 12 h d−1 mean of 0.022 µL L−1). The comparable estimate for data from the WS plot was 7%, but this regression was not statistically significant. Results indicate that soil moisture deficit can decrease the impact of O3 on cotton yield.
Growth of Cotton under Chronic Ozone Stress at Two Levels of Soil Moisture
Authors: Miller Joseph E. , Patterson Robert P. , Heagle Allen S. , Pursley Walter A. , Heck Walter W. 
Published: July 2010

AbstractRecent field research has shown that ambient concentrations of ozone (O3) have the potential to reduce yield of a number of economically important crop species. Soil water levels have been shown sometimes to modify the extent of the reduction. The primary emphasis of most of these studies has been on the plant component that represents economic yield. Less emphasis has been placed on characterization of the effects of O3 on growth of the total plant that ultimately determines yield. In this study, we measured season‐long growth of field‐grown cotton (Gossypium hirsutum L. ‘McNair‐235’) that was exposed to a range of O3 concentrations at two levels of soil moisture, well‐watered (WW) and water‐stressed (WS). The cotton was exposed for 12 h d−1 throughout the growing season in open‐top chambers to five O3 concentrations that ranged from 0.020 to 0.074 µL L−1 (seasonal mean 12 h d−1 concentration). Three cotton plants were sampled from each chamber at 2‐ to 3‐ wk intervals during the season, and biomass and growth measurements were made on all major plant parts. Ozone stress reduced leaf and root biomass in particular, while stem tissues were less affected. Partitioning of biomass among plant tissues was affected by O3 at certain times during the season. Leaf area duration (LAD) was reduced by O3 in both WW and WS treatments, but changes in the yield/LAD ratio and net assimilation rate indicated that reduced efficiency of leaves also was responsible for yield reductions in the WW plots. Water stress caused fewer significant effects overall than did O3, although it appeared to reduce the growth of most plant parts, especially at low O3 concentrations. There were no significant O3 × water interactions for the growth variables measured.
Migration of Technetium, Iodine, Neptunium, and Uranium in the Peat of Two Minerotrophic Mires
Authors: Sheppard Marsha I. , Thibault Denis H. 
Published: July 2010

AbstractMires may become receptors of hazardous wastes transported by the groundwater from surface or underground disposal facilities. Should the contributing water sources contain dissolved solutes, they may sorb onto the organic matter in the mire, precipitate out of solution, or form more or less mobile complexes or colloids. Our study investigated the vertical migration of Tc, I, Np, and U in two types of mires typical of the Precambrian Shield. We also report seasonal groundwater level fluctuations and chemical composition changes in the mires. Our results indicate dramatic seasonal changes in the pH and chemical composition of the groundwater, particularly the concentrations of Na, Mg, Ca, and SO4. Iodine, in spite of being sorbed to the peat with a sorption coefficient, Kd, of 0.2 to 64 L kg−1, migrated quickly through the peat in the porewater. The aeration status and the botanical origin of the peat seem to be factors in the retardation of I. Iodine accumulated on the mire surface in late summer when the water table was lower. However, Tc, U, and Np were quickly immobilized in the reducing environment of the mire and did not migrate very far from their entry point. Geometric mean Kd values for U in the three peats varied from 2600 to 19 000 L kg−1. The Kd values for U did not depend on porewater concentration, humification, or aeration. A comparison between Kd values for U obtained in situ and in laboratory studies showed that our incubation‐sorption system may be a satisfactory technique for U. Neptunium Kd values varied from 31 to 2600 L kg−1 and Tc Kd values were > 2 L kg−1 in these three peats. The Kd values are general indicators of the mobility of these elements in mires, the most mobile being I followed by Tc, Np, and U.
Availability and Form of Copper in Three Soils following Eight Annual Applications of Copper‐Enriched Swine Manure
Authors: Payne G. G. , Martens D. C. , Kornegay E. T. , Lindemann M. D. 
Published: July 2010

AbstractThe use of high levels of Cu in swine (Sus scrofa domesticus) production to stimulate growth and improve feed efficiency is presently being questioned due to the potential environmental hazard from repeated usage of the resulting Cu‐rich manure in agricultural land. Three field studies were established in 1978 and continued through 1985 to determine the effects of long‐term applications of Cu, as either CuSO4 or Cu‐enriched swine manure, at high rates on corn (Zea mays L.) production. The studies were conducted on Bertie fine sandy loam (Aquic Hapludults), Guernsey silt loam (Aquic Hapludalfs), and Starr‐Dyke clay loam (Fluventic Dystrochrepts‐Typic Rhodudults) in the Coastal Plain, Ridge and Valley, and Piedmont regions of Virginia, respectively. These soils have CEC ranging from 5.0 to 12.3 cmolc kg−1. According to USEPA guidelines, which are based on the CEC values and pH levels ≥6.5, the three soils have a maximum safe Cu loading rate of 280 kg Cu ha−1. After 8 yr, 890.4 t ha−1 of wet Cu‐enriched manure had been applied to these soils. The manure contained up to 1550 mg Cu kg−1 and was produced by pigs fed diets with an average of 251 mg Cu kg−1. Application of 336 kg Cu ha−1 as CuSO4, or up to 264 kg Cu ha−1 as Cu‐enriched manure, from 1978 through 1985 did not decrease corn grain yields on the three soils. The eight annual Cu applications increased Cu concentrations in ear leaf tissue by ≤2.1 mg kg−1, but did not affect the Cu concentrations in the grain. The Cu levels in all plant tissue remained within normal ranges. Diethylenetriaminepentaacetic acid (DTPA)‐extractable Cu was linearly related to the amount of Cu applied to the three soils (r = 0.93−0.98, α = 0.01) and was unrelated to Cu levels in grain or leaf tissue. Small increases, up to 1.6 mg Cu kg−1, in extractable Cu in the B horizons of the Bertie and Starr‐Dyke soils indicated little downward movement of the applied Cu. Larger increases in extractable Cu in the Guernsey subsoil were attributed to downward movement caused by plowing. Copper fractionation data indicated that a substantial portion of the applied Cu has reverted to forms not available to plants.
Effects of Sewage Sludge on Di‐(2‐Ethylhexyl) Phthalate Uptake by Plants
Authors: Aranda J. M. , O'Connor G. A. , Eiceman G. A. 
Published: July 2010

AbstractDi‐(2‐ethylhexyl) phthalate (DEHP) is a priority organic pollutant frequently found in municipal sludges. A greenhouse study was conducted to determine the effects of sludge on plant uptake of 14C‐DEHP (carbonyl labeled). Plants grown included three food chain crops, lettuce (Lactuca sativa L.), carrot (Daucus carota L.), and chile pepper (Capsicum annuum L.) and tall fescue (Festuca arundinacea Schreb.) Net 14C concentration in plants grown in soil amended with 14C‐DEHP‐contaminated sludge was independent of sludge rate (at the same DEHP loading) for lettuce, chile fruit, and carrot roots. Net 14C concentration, however, was inversely related to sludge rate in carrot tops, fescue, and chile plants. Intact DEHP was not detected in plants by gas chromatography/mass spectrometry analysis. Calculated plant DEHP concentrations (based on measured net 14C concentrations and DEHP specific activities) were generally correlated better with DEHP soil solution concentrations than with total DEHP soil concentrations. Net 14C‐DEHP bioconcentration factors were calculated from initial soil DEHP concentration and plant fresh weights. Bioconcentration factors ranged from 0.01 to 0.03 for fescue, lettuce, carrots, and chile, suggesting little DEHP uptake. Additionally, because intact DEHP was not detected in any plants, DEHP uptake by plants was of minor importance and would not limit sludge additions to soils used to grow these crops.
Simulating the Fate of a Volatile Pesticide in Unsaturated Soil: A Case Study with DBCP
Authors: Wagenet R. J. , Hutson J. L. , Biggar J. W. 
Published: July 2010

AbstractA field experiment that measured DBCP (1,2‐dibromo‐3‐chloropropane) distribution during leaching through unsaturated soil was interpreted with the aid of a numerical model designed to describe the movement of a volatile pesticide under field conditions. Field‐measured relationships between hydraulic conductivity, water content, and matric potential were used as model input. Simulated matric potential and water flux compared well with values measured in the field plots. The accuracy of simulated water flow inferred accurate solute description, particularly considering good agreement of the model with a published analytical solution and other reported field tests of the model. Simulated and measured DBCP solution concentrations were different, probably due to the use of a vacuum extraction apparatus to obtain soil solution samples. It was hypothesized that substantial quantities of DBCP were lost in the gaseous form during the extraction process, minimizing the usefulness of the data for the purpose of estimating DBCP fate under field conditions. Given these facts, the numerical model provided estimates of DBCP fate in field soils that were perhaps more reliable and accurate than could be obtained for this volatile chemical by standard field sampling techniques.
Land‐Use and Water Quality in Tributary Streams of Lake Tahoe, California‐Nevada
Authors: Byron Earl R. , Goldman Charles R. 
Published: July 2010

AbstractWe examined land‐use and water quality monitoring data for 10 watersheds of tributary streams to Lake Tahoe, California‐Nevada, to describe relationships between watershed disturbance and water quality degradation from nonpoint sources. Discharge‐weighted annual average concentrations of nitrate (as NO3‐N), soluble P, total P and suspended sediment were plotted against the proportion of each watershed represented as disturbed and imperviously covered land of various land‐use classes. Comparisons between land‐use and runoff water quality demonstrated significant relationships between increased coverage and disturbance in the watersheds and decreased water quality. The concentrations of NO3‐N, total P, and suspended sediment in the streams increased significantly with the disturbance of high hazard lands (erodible soils, steep slopes, stream environment zones). Increased disturbance of lower hazard lands (less erodible soils) resulted in increases in the concentrations of soluble and total P. The patterns of significance and slopes of the relationships demonstrated increased nonpoint source water quality degradation with increased land disturbance in these Sierra Nevada watersheds.
Mineralization and Leaching of Phosphorus from Soil Incubated with Surface‐Applied and Incorporated Crop Residue
Authors: Sharpley A. N. , Smith S. J. 
Published: July 2010

AbstractWith the increasing use of conservation tillage, consideration of crop residue as a potential source of plant‐available P and mobility of this P in soil will be important from both agronomic and environmental standpoints. The effect of placement (surface or incorporation) of residue of six crop types (alfalfa, Medicago sativa L.; corn, Zea mays L.; oat, Avena sativa L.; peanut, Arachis hypogaea L.; soybean, Glycine max (L) Merr.; wheat, Triticum aestivum L.) on the mineralization and leaching of P from eight soils was investigated. Significantly greater (1.0% level) amounts of inorganic P were leached from surface‐applied compared to incorporated residues during the 84‐d incubation at 35°C, with the maximum amount leached after 28 d. The opposite was true for organic P, with greater amounts leached from incorporated residue than from surface‐applied residue. These amounts steadily decreased during the 84‐d incubation. Apparently, mineralization of residue P and movement within the soil was greater for surface‐applied compared to incorporated residue and was a positive linear function of available soil P content (r2 = 0.69–0.81). Any increase in soil P solubility caused by residue leachate would be expected to occur to a greater extent with an increase in available soil P. Leaching of mineralized P may be an important source of available P during initial crop growth.
Dissipation of Bentazon in Flooded Rice Fields
Authors: Ross L. J. , Powell S. , Fleck J. E. , Buechler B. 
Published: July 2010

AbstractThe dissipation of bentazon (3‐isopropyl‐1H‐2,1,3‐benzothiadiazin‐4(3H)‐one 2,2‐dioxide) in water, soil and vegetation from three flooded rice (Oryza sativa L.) fields was investigated in California. Regression analyses were used to describe dissipation and to determine half‐lives. Maximum bentazon concentrations in water, soil and vegetation were 2100 µg/L, 960 µg/kg and 23,000 µg/kg, respectively. Concentrations in water showed a gradient from the upper to lower end of the fields over time and were related to movement of bentazon downfield in flood water. Bentazon mass recovered in water samples was not linear over time but was related to degradation, dilution, application rate and mass flow within a field. In water, the time estimated for a 50% reduction in initial bentazon mass ranged between 11 and 32 d after application for the three fields. Bentazon mass in soil declined exponentially over time and the dissipation half‐life was calculated to be 5 d. Bentazon mass recovered from vegetation samples was not linear over time but was related to degradation and wash‐off from plant surfaces. The time estimated for a 50% reduction in initial bentazon mass in and/or on vegetation was between 2 and 3 d after application. Dissipation rates determined in this study were different than published results from small field plots and from laboratory data, indicating the need for field measurements in the development of regulatory strategies.
Comparison of Lumped and Distributed Models for Chemical Transport by Surface Runoff
Authors: Emmerich W. E. , Woolhiser D. A. , Shirley E. D. 
Published: July 2010

AbstractA simple, complete mixing model is used to evaluate the degree of distortion involved in modeling chemical exchange and transport at the soil surface as a lumped rather than a distributed process. A complete mixing model was coupled to the kinematic cascade model, KINEROS, to provide a distributed representation of chemical exchange and transport. A lumped model was developed by ignoring spatial variations of chemical concentration in overland flow and in the mixing zone. Chemical concentration and transport predicted by the alternative approaches were evaluated for total transport, arrival time, peak concentration time, and peak concentration. Total chemical transport was virtually unaffected by model form. However, significant differences were found in arrival and peak concentration times as well as peak concentrations when chemical was placed only in the upper plane of a two plane cascade. The lumped model predicted significantly lower peak chemical concentrations and arrival times that were too short. A lumped model provides a good approximation for transport from a single plane, but caution should be used when a lumped model is used to describe chemical exchange and transport on a cascade of planes.
Chemistry of Rainwater and Cloud Water at Remote Sites in Alaska and Oregon
Authors: Bormann B. T. , Tarrant R. F. , McClellan M. H. , Savage T. 
Published: July 2010

AbstractCloud water and rainwater were examined at remote sites in southeastern Alaska and coastal Oregon using standardized collection and analytical techniques. Cloud water and rainwater were characterized by extremely low concentrations of most ions except SO2−4, Na+, and Cl−. Acidity was greater than expected because of organic acids from unknown sources. Concentrations of NO−3 and NH+4 were extremely low, especially compared to samples collected similarly in the eastern USA. Rainwater did not differ between Alaska and Oregon except in concentrations of Ca2+, Mg2+, K+, Na+, and Cl−. Cloud water generally had higher concentrations of ions than rainwater, especially in NO−3, NH+4, and SO2−4. Ion concentrations were highly variable and non‐normally distributed. Sample sizes in future studies should be large (>40). Cloud water deposition may be very important in terms of potential pollution effects and nutrient cycling in ecosystems with frequent cloud cover.
Reasons for the Acclimation for 2,4‐D Biodegradation in Lake Water
Authors: Chen Shaojin , Alexander Martin 
Published: July 2010

AbstractA study was undertaken to determine reasons for the occurrence of an acclimation period for the biodegradation of 2,4‐dichlorophenoxyacetate (2,4‐D) in lake water. The length of the acclimation period was not affected by removal of larger protozoa from the water or the presence of cycloheximide and nystatin. The population of 2,4‐D‐degrading bacteria increased long before 2,4‐D loss was detected, and herbicide loss was evident only when the population size was large. The acclimation phase was virtually eliminated if a culture of 2,4‐D‐utilizing bacteria was added to lake water. A culture of glucose‐grown 2,4‐D‐degrading bacteria metabolized the herbicide in a time interval far shorter than the acclimation phase. The time for acclimation was identical in 14 replicate samples of the same lake water. These data suggest that the length of the acclimation phase is not mainly a result of the time for reduction of grazing pressure on 2,4‐D‐degrading bacteria, the destruction of antimicrobial compounds, the decomposition of alternative C sources used preferentially to the herbicide, induction of the requisite enzymes, or the appearance of a mutant able to utilize the pesticide. The acclimation for 2,4‐D degradation in lake water appears chiefly to reflect the time for a small population of bacteria able to use the compound to become sufficiently large to cause a detectable loss of the chemical.
Application of Sewage Sludge and Other Amendments to Coal Refuse Material: I. Effects on Chemical Composition
Authors: Pietz R. I. , Carlson C. R. , Peterson J. R. , Zenz D. R. , Lue‐Hing C. 
Published: July 2010

AbstractThe effects of sewage sludge, lime, and gypsum on the chemical composition of coal refuse material were examined at a Fulton County, IL, land reclamation site. Treatments consisted of a control, 542 dry Mg ha−1 anaerobically digested sewage sludge, 89.6 Mg ha−1 lime, 112 Mg ha−1 gypsum, and combinations of these amendments. Analysis of coal refuse material (0–15 cm) from 1976 to 1981 showed that the sewage sludge + lime treatment was the most effective in maintaining the refuse pH, and in reducing water‐soluble Al and Fe, KCl extractable Al, and total acidity. Gypsum applications decreased the refuse pH and increased water‐soluble Al and Fe, KCl extractable Al, and total acidity. The effectiveness of treatments in reducing total acidity was sewage sludge + lime > gypsum + sewage sludge + lime > sewage sludge > lime > gypsum + sewage sludge > control > gypsum + lime > gypsum. Concentrations of water‐soluble Ca, Mg, and Na reflected the additions of these cations made by various treatments and the contribution of these cations to refuse electrical conductivity (EC). Profile sampling (0–100 cm) in 1976 and 1981 showed a decline in pH, and an increase in water‐soluble Al and Fe and total acidity in 1981 samples from the sewage sludge and gypsum treatments. The changes in the sludge treatment indicate there was a solubilization of metals from the refuse material and sewage sludge with time, as the surface pH (0–15 cm) declined, and a subsequent increase in the total acidity from metals and acidic by‐products leached to the 15‐ to 100‐cm depths of the coal refuse material. In the gypsum treatment, the changes observed in the 1981 profile samples reflected the leaching of H3O+, metals, and acidic by‐products of pyrite oxidation produced by exchange with Ca from the gypsum amendment.
Effects of Ozone and Water Stress, Separately and in Combination, on Soybean Yield
Authors: Miller Joseph E. , Heagle Allen S. , Vozzo Steven F. , Philbeck Robert B. , Heck Walter W. 
Published: July 2010

AbstractA primary concern in applying existing 03‐effects data on crop production is the relatively unknown influence of soil moisture, which may modify plant response to 03. One deficiency in field experiments that have tested the influence of soil moisture on crop response to 03 has been lack of control of soil moisture conditions in open‐top chamber plots. Most experiments have relied on the occurrence of normal drought periods during the growing season and use of irrigation to adjust soil moisture conditions. This has not allowed the control of the water stress cycles that is desirable. In 1986 a field experiment was performed with soybean [Glycine max. (L.) Merr. cv. Young] to test the influence of periodic water stress on the yield response to O3. Open‐top field chambers were used to expose plants to a range of O3 concentrations, and rain exclusion caps were used on individual chambers to help regulate soil moisture levels. Three soil moisture treatments were used [well‐watered (WW), waterstressed (WS), and well‐watered with permanent rain exclusion caps that were in place from 35 d after planting until physiological maturity (WW‐C)]. In the WW and WS treatments, the rain caps were put in place only during an exceptionally wet period from mid‐August to mid‐September. The WW and WW‐C treatments had approximately the same yield and response to O3, indicating that the presence of the caps for most of the growing season had little effect on growth or sensitivity to O3. The WS plots yielded approximately 10% less on the average than the WW and WW‐C plots, but water stress did not change the response to O3 (i.e., no significant O3 × water interaction). Based on a Weibull dose‐response model, O3 reduced yield of ‘Young’ soybean 13% at a concentration of 0.05 µL L−1 (12 h d−1 seasonal mean) compared to a hypothetical background of 0.02 µL L−1.