bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phytotoxicity in Bush Bean of Five Sulfur‐Containing Gases Released from Advanced Fossil Energy Technologies
Authors: Taylor G. E. , Selvidge W. J. 
Published: July 2010

AbstractSulfur‐containing gases including sulfur dioxide (SO2), hydrogen sulfide (H2S), carbon disulfide (CS2), carbonyl sulfide (COS), and methyl mercaptan (CH3SH) are a major class of atmospheric emissions from advanced fossil energy technologies. Although phytotoxicity data for SO2 and H2S exist, the influence on vegetation of the remaining S gases is not known. This study was designed to address the comparative toxicity of the five gases in bush bean (Phaseolus vulgaris). Seedlings were exposed to each gas individually for 6 hr at a range of concentrations (6–82 µmol m−3) in an open gaseous exchange system, during which whole‐plant net photosynthesis and transpiration were monitored. At the highest exposure levels, leaf necrosis was assessed 3 d after exposure. Transpiration did not respond consistently to any of the treatments. Neither CS2 nor CH3SH caused any change in photosynthesis or foliar necrosis. Based on the inhibition of photosynthesis and the development of leaf necrosis at equivalent volumetric concentrations in the atmosphere, the toxicity of the remaining three gases was SO2 > H2S > COS. The relationship between net photosynthesis and exposure dosage (concentration × time) for H2S, SO2, and COS was curvilinear and biphasic, exhibiting in each gas an enhancement of photosynthesis followed by inhibition as the dosage increased. For projected emission rates from advanced fossil energy facilities, the results suggest that releases of CH3SH and CS2 are not likely to influence vegetation. Since plant response to H2S, SO2, and COS is strongly dosage dependent, accurate estimates of field effects due to these three gases must await more adequate air quality modeling near commercial‐scale facilities.
Effects of Aeration and Temperature on Nutrient Regeneration from Selected Aquatic Macrophytes
Authors: Ogwada R. A. , Reddy K. R. , Graetz D. A. 
Published: July 2010

AbstractA batch incubation study was conducted to investigate the effect of aeration and temperature on the N and P release by decomposing aquatic macrophytes in eutrophic lake water. Nutrient release by waterhyacinth (Eichhornia crassipes [Mart] Solms), pennywort (Hydrocotyle umbellata L.), hydrilla (Hydrilla verticillata L.), and cattails (Typha latifolia L.) was evaluated under aerobic conditions. Waterhyacinth plants tagged with 15N were used to determine the 15N release at varying temperature levels and under anaerobic (oxygen free) and low‐dissolved O2 (open system where the only O2 source was diffusion through the overlying water) conditions.Nutrient release was found to be rapid initially due to solubilization, followed by slow nutrient release as a result of microbial decomposition. Under aerobic conditions, NO3− formation in the water was found to be significantly related to C/N ratio of the plants. About 48 to 76% of the plant N and 67 to 90% of the plant P were released at the end of 105 d of aerobic decomposition. After 94 d, about 86 and 88% of 15N was released from the plant tissue under anaerobic and low‐dissolved O2 conditions, respectively. Nitrogen and phosphorus release were significantly increased with increase in incubation temperature.
Contamination of the O2 Soil Horizon by Zinc Smelting and its Effect on Woodlouse Survival
Authors: Beyer W. N. , Miller G. W. , Cromartie E. J. 
Published: July 2010

AbstractSamples of litter from the O2 horizon of Dekalb soil (loamy‐skeletal, mixed, mesic Typic Dystrochrept) were collected from 18 ridgetop sites on a transect that ran by two Zn smelters in Palmerton, Pa. Metal concentrations increased by regular gradations from a minimum at a site 105 km west of the smelters (67 mg/kg Zn, 0.85 mg/kg Cd, 150 mg/kg Pb, 11 mg/kg Cu) to a maximum 1.2 km east of the smelters (35 000 mg/kg Zn, 1300 mg/kg Cd, 3200 mg/kg Pb, 280 mg/kg Cu), and then decreased until they reached an eastern minimum at the easternmost site, 19 km from the smelters. An increase in the P concentrations near the smelters showed that the emissions were disrupting nutrient flow through the ecosystem. An increase in the pH near the smelters was attributed to the high concentrations of Zn. The log of the distance of the sites from the smelters was significantly correlated (r = −0.80, p < 0.05) with the mortality of woodlice (Porcellio scaber Latreille) fed samples of the litter during an 8‐week test. There was substantial mortality of woodlice observed even in the O2 litter collected 19 km east of the smelters. Zinc, cadmium, lead, copper, and sulfur were experimentally added, alone or in combination, to O2 litter collected far from any known source of metal emissions. The highest concentration of Zn added (20 000 mg/kg) was toxic enough to account for the mortality observed in the earlier test. A lower concentration of Zn (5000 mg/kg) as well as the concentration of Cd (500 mg/kg) tested also significantly (p < 0.05) increased the mortality of woodlice.
An Approach to Predicting the Movement of Selected Polluting Metals in Soils
Authors: Amoozegar‐Fard A. , Fuller W. H. , Warrick A. W. 
Published: July 2010

AbstractAn approach is developed to derive simple, field‐oriented equations to predict movement of pollutant metals in soils. The procedure is illustrated by a comprehensive example utilizing experimental work on small columns with Cd, Ni, and Zn on nine soils and eight landfill‐type leachates. The results provide a set of simple equations to predict movement of the three metals through soils with minimal calculations. The final form enables the scientist or field engineer to calculate velocities for which a given concentration of the metal is propagated through the soil profile. The simplified forms are based on the Lapidus‐Amundson (L.A.) model, for which apparent diffusion and forward and backward reaction coefficients are best fitted to whatever experimental data are available. The L.A. model is then used to generate the propagation velocities for constant concentration, which are related back to the soil and leachate properties by multiple regression. The regression equation is what the field person uses and the choice of coefficients is based on available input data. The specific coefficients developed for this data‐set may be used directly if no other experimental data are available for a given site.
Nitrate Leaching as Influenced by Water Application Level and Nitrification Inhibitors
Authors: Timmons D. R. 
Published: July 2010

AbstractThe effects of water application level and nitrification inhibitors on NO3−‐N leaching from a sandy loam soil were evaluated using soil columns and nonweighing field lysimeters. In soil columns (297 mm diam by 1.2 m deep) fertilized with 224 kg N ha−1, addition of the nitrification inhibitor nitrapyrin [2‐chloro‐6‐(trichloromethyl)pyridine] reduced NO3−‐N leaching losses by 51 and 30 kg ha−1, respectively, for the 12.7‐ and 38.1‐mm weekly water application levels. Both nitrapyrin and Terrazole (5‐Ethoxy‐3‐trichloromethyl‐1,2,4‐thiadiazole) (Olin Corp., Little Rock, Ark.) inhibitors were equally effective in reducing total NO3−‐N leaching losses from soil columns after 100 d for the 38.1‐mm water application level. The change in flow‐weighted NO3−‐N concentration due to use of nitrification inhibitors was about −0.4 to −1.0 mmol L−1.Annual NO3−‐N leaching losses measured at the 1.2‐m depth in field lysimeters cropped with corn (Zea mays L.) over a 3‐yr period averaged about 12 kg ha−1 less (7%) for nitrapyrin‐coated urea. The results were not consistent since nitrapyrin reduced NO3−‐N leaching during the growing season by 12 and 17% for 2 of the 3 yr and post season leaching by 35% for 1 yr. The change in flow‐weighted NO3−‐N concentration (3‐yr avg) due to nitrapyrin was −0.4, −1.5, and +0.9 mmol L−1, respectively, for the growing season, post season, and preemergence periods. Nitrification inhibitors may help to minimize nonpoint‐source pollution on sandy soil where supplemental irrigation is used by reducing and/or delaying NO3−‐N leaching particularly during the growing season when N is utilized by plants.
Plant Availability of Heavy Metals in a Sludge‐Treated Soil: II. Metal Extractability Compared with Plant Metal Uptake
Authors: Singh B. R. , Narwal R. P. 
Published: July 2010

AbstractA greenhouse study was conducted to investigate the uptake of Cd, Ni, Pb, Co, and Zn by fodder rape (Brassica napus L. ‘Kenton’) and extractability of these metals from sewage sludge‐treated soils at different levels of sludge application and soil pH. Metals extracted by several extractants were correlated to their uptake by rape. Total uptake of Cd, Ni, Pb, and Zn increased and that of Co decreased as the rate of sludge application increased. Uptake of all metals except Pb generally decreased as soil pH increased.The extractability of most metals was in the order: HNO3 > aqua regia > HCl > NH4OAc (pH 4.8) > DTPA > H2O. It was governed by rates of sludge application but was little affected by change in soil pH. The percentage of exchangeable form of all metals was < 1% and 90 to 99% of the total metals in sludge‐treated soils was bound in organic and sulfide forms.Cadmium extracted by HCl, NH4OAc (pH 4.8), and diethylenetriaminepentaacetic acid (DTPA) as well as that determined after digestion of soil with HNO3 and aqua regia showed significant correlation with its uptake by rape. The same was true for Pb except for HNO3, where correlation coefficient was not significant. For Co, Ni, and Zn, none of the extractants used gave an adequate prediction of their plant availability, as most of the correlation coefficient values obtained were low. Of the extractants used in this study, though none gave a reliable prediction of plant availability of all the metals, DTPA yielded significant r values for Cd and Pb. Thus, DTPA may be considered better than other extractants for predicting the availability of Cd, Pb, and possibly Zn in fodder rape under varying levels of sludge application and soil pH.
Nitrogen Balance in a Citrus Orchard
Authors: Dasberg S. , Erner Y. , Bielorai H. 
Published: July 2010

AbstractDifferential fertilizer and irrigation applications were utilized to assess the N balance over a period of 4 yr in a typical mature ‘Shamouti’ orange (Citrus sinensis L.) grove located in the coastal plain of Israel. Nitrogen inputs in fertilizer and irrigation water were 100, 180, and 310 kg ha−1 annually for the three main treatments. The N removed by the crop was measured by yield and N content determinations in the fruits; the leached N was measured by sampling below the root zone. It was found that the amount of leached N was similar in the low and medium N applications (< 50 kg N ha−1). At the high N application, > 50 kg N ha−1 was leached and large amounts of N were unaccounted for (approximately 100 kg N ha−1). Analysis of published data on N losses from citrus orchards showed similar large amounts of N not found in the fruit or in the soil mineral N pool after large N applications. The possible pathways for these N losses were discussed. It was concluded that this excess N was either incorporated in the soil organic matter or stored in the tree rather than being denitrified.
Fate and Effectiveness of Tebuthiuron Applied to a Rangeland Watershed
Authors: Emmerich W. E. , Helmer J. D. , Renard K. G. , Lane L. J. 
Published: July 2010

AbstractTebuthiuron3 (N‐[5‐(1,1‐Dimethylethyl)‐1,3,4‐triadiazol‐2‐yl]‐N.N′‐dimethylurea), a herbicide, was applied at a rate of 0.84 kg/ha to a rangeland watershed and test plots in pelleted and dissolved forms, respectively. The removal of tebuthinron in the runoff water from the watershed was determined for each runoff event. After 21 months, total tebuthiuron removed in runoff water was 0.47% of that applied. The low removal rate was credited to the timing of the tebuthiuron application. Tebuthiuron applied to test plots moved to a depth of 15 cm in 8 months with 326 mm of precipitation. Total tebuthiuron remaining in the test plots after 21 months was 38% of the amount applied. The time required for the concentration of tebuthiuron in the test plots to reach non‐detectable levels was estimated to be from 2.9 to 7.2 years. Tebuthiuron was effective on the dominant species on the watershed 21 months after treatment, producing an apparent 100% kill for tarbush (Flourensia cernua DC.), fourwing saltbush [Atriplex canescens (Pursh) Nutt.], and littleleaf sumac (Rhus microphylla Engelm. ex Gray), and 61, 92, and 0% for creosote‐bush [Larrea tridentata (DC.) Cov.], whitethorn (Acacia constricta Benth.) and graythorn (Condalia spathulata Gray), respectively.
Effects of Acidic and Neutral Sulfate Salt Solutions on Forest Floor Arthropods
Authors: Craft C. B. , Webb J. W. 
Published: July 2010

AbstractAcidic and neutral SO42− solutions were applied to a mixed oak (Quercus spp.) forest floor on Walker Branch Watershed in eastern Tennessee to study effects of increased acid deposition on decomposer arthropods and arthropod regulation of P cycling. Treatments consisted of ambient (no applications), 2 × (low), and 10 × (high) annual atmospheric inputs of SO42− (as K2SO4) and H+ plus SO42− (as KHSO4). Arthropods were sampled monthly in litter and mineral soil. Soils were analyzed for Bray no. 2 P and for salt pH, NH4Cl exchangeable Al3+ and K+, and water‐extractable SO42−.Over a 14‐month period, the number of forest floor macroarthropods averaged 19% lower in the high SO42− salt treatment compared with the control. Macroarthropod fungivores also were adversely affected by the high SO42− salt treatment and by the high and the low KHSO4 treatments. The effects of the high SO42− treatment on macroarthropods may have resulted from a salt effect caused by the concentrated K2SO4 applications (112 mmol K+ m−2 per application). Microarthropod numbers increased significantly in response to the low K2SO4 additions and to the high and low KHSO4 treatments. Microarthropod fungivores, predators, and detritivores responded similarly. Comparison of microarthropod densities and soil K+ concentrations suggested that the response resulted from a direct fertilizer effect of K+ on arthropods or indirectly from an effect on microorganisms.Mineral soil pH, exchangeable Al3+, and Bray P were unaffected by the treatments. Soil pH (0–15 cm) was unaffected by the KHSO4 applications because most of the H+ addition was neutralized by the forest floor. Analysis of litter leachate during a single treatment interval (5 weeks) indicated that only 31% of the H+ applied in the high KHSO4 treatment reached the mineral soil.Although increased inputs of H+ appear to have little effect on decomposer arthropods, effects of nonacidic SO42− warrant further study.
Effect of Loading Rate and Soil Amendments on Inorganic Nitrogen and Phosphorus Leached from a Wastewater Soil Absorption System
Authors: Uebler R. L. 
Published: July 2010

AbstractPermissable wastewater loading rates for ground absorption sewage disposal systems in North Carolina are currently estimated from an on‐site characterization of soil texture and structure; but, after the trenches of the system are dug, the actual ability of the soil to absorb the applied wastewater may be far less than the estimated loading rate due to smearing of the trench‐soil interface. This study was designed to evaluate the effects of wastewater loading rate and soil amendments proposed to help overcome the detrimental effect of soil smearing on wastewater treatment by a soil absorption system.Three loading rates, 7.5, 11.3, and 15.0 L m−2 d−1, were tested and two soil amendments, cement and lime, were compared with a control. The amendments were added to the soil on a 5% by‐weight basis. Three absorption trenches, 3.0 m in length, were dug for each loading rate‐soil amendment combination. Soil water samples were obtained monthly for 12 months from ceramic cups placed 15 and 30 cm below the trenches. Water samples were analyzed for NH4+‐N, NO3+‐N, soluble P, chloride and pH.Concentrations of NH4+‐N, NO3−‐N, and soluble P varied significantly with the time of sampling. Transformation of NH4+‐N to NO3−‐N was enhanced by the soil amendments, indicating that the aeration status of the soil near the trenches was improved by the amendments. The effect of the amendments was most noticeable during the spring recovery period as aeration status was increasing from winter minimums. Higher NO3−‐N levels for the cement as compared with the lime in spring suggest that cement may be a more effective amendment than lime. The lowest loading rate had significantly higher concentrations of NO3−‐N during the spring months. Soluble P levels increased linearly from 0.1 to 0.9 mg L−1 over the first year operation of the system.
Adsorption of Phosphate, Arsenate, Methanearsonate, and Cacodylate by Lake and Stream Sediments: Comparisons with Soils
Authors: Wauchope R. D. , Mc Dowell L. L. 
Published: July 2010

AbstractThe adsorption of phosphate, arsenate, MSMA (sodium methanearsonate) and cacodylic acid (hydroxydimethylarsine oxide) by 14 sediments from streams and lakes of the Mississippi River alluvial flood plain was measured using a phosphate fixation test and also dilate (1 g/100 mL) sediment‐water slurries at 50 and 500 µg/L P or As. The fixation experiment results were similar to a previous study with soils from the same geographic area in that sorption of the four species were similar and correlated with clay and extractable Fe and Al content. In contrast with the soils results, phosphate was more strongly adsorbed than the arsenicals because the sediments were richer in Fe and Al oxides than soils of the same clay content and the phosphate sorption index was most dependent on sediment Fe and Al content. Conversely, the arsenicals were most correlated with clay or Fe content. Arsenical fixation also exhibited some sediment‐pH dependence indicative of binding with Ca. In the dilute slurry experiments, the high‐clay sediments were extremely adsorptive of all the species and yielded equilibrium P concentration (EPC) values from 0.07 to 0.3 µg/L P. Cacodylate adsorption was dependent on sediment pH. Those sediments with high clay content had a very large unfilled capacity to adsorb phosphate or arsenate, and would act as sinks for P or As inputs into their associated lakes or streams.
Nitrous Oxide Emissions from Agricultural Soils in Wisconsin
Authors: Goodroad L. L. , Keeney D. R. , Peterson L. A. 
Published: July 2010

AbstractNitrous oxide (N2O) emissions from field plots on a Plano silt loam soil (Typic Argiudolls) at the University of Wisconsin‐Arlington Experimental Farm were measured from the summer of 1979 through autumn 1981. The treatments, selected to give a wide variation in management, were: reduced tillage (till‐plant) corn (Zea mays L.); rye (Secale sativa L.) cover; long‐term stable pH (pH 4.7, 5.1, and 6.7); oat (Avena sativa L.) straw residue; alfalfa (Medicago sativa L.) residue; and dairy manure and sewage sludge amendments. Nitrous oxide fluxes, measured by a static chamber technique, were greatest with the manure‐amended and reduced tillage treatments, and were greater in 1980 than in 1979 or 1981. Highest rates of N2O emission were often observed at soil thaw. No significant effects on the emission rate or amount of N2O evolved due to soil pH was observed. Surface N2O fluxes were characterized by a high degree of variation. Mean N2O‐N emission rates calculated from measured N2O‐N emission rates during annual sampling periods ranged from 1.6 to 38.7 ng N2O‐N m−2 s−1 for the treatments sampled. Coefficients of variation for these means ranged from 50% to > 200% and from 100 to 350% for spatial and temporal variability, respectively. Total N2O emissions (kg N2O‐N ha−1) for 1980, the most complete sampling period, were: reduced tillage corn, 3.5 in the row and 6.3 between the row; sludge, 1.6; manure, 6.1; alfalfa, 3.2; rye, 1.6; straw, 2.2; pH 4.7, 1.5; pH 5.1, 0.9; pH 6.7, 1.0. These values are similar to those reported in the literature from comparable agricultural sites.
Predicted Erosion and Sediment Delivery of Fallout Plutonium
Authors: Foster G. R. , Hakonson T. E. 
Published: July 2010

AbstractPlutonium (Pu) from fallout after atmospheric explosion of nuclear weapons in the 1950s and 1960s is being redistributed over the landscape by soil erosion and carried on sediment by streams to oceans. Erosion rates computed with the Universal Soil Loss Equation for about 200 000 sample points on nonfederal land across the USA were used to estimate Pu removal rates by soil erosion by water, Pu delivery in several major rivers, and concentration of Pu on the transported sediment. Estimates of average annual Pu delivery on sediment ranged from 0.002% of the initial fallout Pu inventory for the Savannah River basin to 0.08% for the Mississippi River basin. If the deposition of Pu had been uniformly 37 Bq/m2, the estimated Pu activity on suspended sediment ranged from about 0.26 Bq/kg of sediment for the Savannah River basin to 0.52 Bq/kg for the Columbia and Rio Grande river basins. After 1000 yr, about 9 to 48% of the initial Pu inventory will remain in U.S. soils that are eroding. Much of the Pu on eroded sediment will travel only a short distance from its origin before its host sediment particles are deposited and permanently located, at least for a few hundred years. As much as 90% of the initially deposited Pu will remain, redistributed over the landscape by erosion and deposition. Although the delivery rate of Pu by rivers will not decrease greatly in the next 100 yr, a significant decrease will likely occur by 1000 yr.
Estimating Labile and Dissolved Inorganic Phosphate Concentrations in Surface Runoff
Authors: Wendt R. C. , Alberts E. E. 
Published: July 2010

AbstractMathematical models are needed to better estimate effects of alternative management methods on the amounts of bioavailable P lost in surface runoff over a variety of soil, topographic, and climatic conditions. In this study, methods for estimating concentrations of soil‐derived labile (dissolved plus adsorbed) and dissolved P in runoff are proposed and tested. The methods are based on the assumption that most labile P contributed by soil to runoff is derived from soil particles that are detached and transported with runoff water. Effects of erosive selectivity are accounted for by dividing soil and sediment into five undispersed size fractions. Isotherms relating adsorbed labile and dissolved P levels were developed for each from soil analyses. Labile P concentrations in runoff were estimated by summing the product of labile P concentrations prior to entrainment in runoff and measured sediment concentrations for each of the size fractions. Dissolved P concentrations were estimated by distributing labile P between dissolved and adsorbed forms using a mass balance approach. Methods of estimation were tested with runoff from 14 natural rainstorms occurring on 10 fallow plots having soil P levels ranging from about 1.3 to 3.2 mmol kg−1 as labile P. Linear regressions of observed on estimated values of both labile and dissolved P were significant. For most events, slopes and intercepts of regression lines were not significantly different from one and zero, respectively, indicating good absolute agreement. Results indicate that soil analyses in combination with models for predicting the amount and size distribution of eroded soil form a basis for estimating movement of bioavailable P forms in runoff. However, additional studies are needed to determine the range of soil types for which the assumptions inherent in the development of the approach are valid.