bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced Biodegradation of Polychlorinated Biphenyls in Soil by Analog Enrichment and Bacterial Inoculation
Authors: Brunner Walter , Sutherland Fain H. , Focht Dennis D. 
Published: July 2010

AbstractCarbon‐14‐labeled polychlorinated biphenyls (PBC) representing the commercial Aroclor 1242 mixture (a mixture of chlorinated biphenyls) were incubated in soil over a 210‐d period to determine if biodegradation could be enhanced by additions of straw and sludge, aerobic and anaerobic incubations, or combinations thereof. Although PCB (100 mg/kg) had no effect on microbial respiratory processes in soil, mineralization did not exceed 3% of the total added. Also, neither 14CO2 nor 14CH4 was produced from anaerobic incubations, although both gases were produced from organic matter additions. Further experimentation was undertaken to investigate the possibility that the soil lacked either an indigenous microflora capable of metabolizing PCB or a suitable substrate analog which promoted their activity or growth. Inoculation with Acinetobacter P6 (Furukawa) alone did not enhance mineralization of 14C‐PCB. However, when enriched with substrate analog biphenyl, 20 to 27% of the label was recovered as 14CO2 over a 63‐d period compared to < 1% 14CO2 for the unenriched controls. Uninoculated and enriched treatments also greatly enhanced mineralization yielding 15 to 20% as 14CO2, yet the extent of primary degradation of PCB (i.e., disappearance) was greater when both Acinetobacter and biphenyl were added. Analog enrichment with biphenyl is the most important factor effecting PCB degradation in soil, but additional enhancement is brought about by inoculation with Acinetobacter, which is superior to the indigenous microflora with respect to diversity towards metabolism of the isomers present in Aroclor 1242.
Soil Tests for Estimating Labile, Soluble, and Algae‐Available Phosphorus in Agricultural Soils
Authors: Wolf A. M. , Baker D. E. , Pionke H. B. , Kunishi H. M. 
Published: July 2010

AbstractThe relationships of three “quick” soil tests for P (Olsen, Bray‐1, and Mehlich I) with labile P, the equilibrium phosphorus concentration in the soil solution (EPC) and algae‐available P (as determined by 0.1 M NaOH extraction) were examined for a diverse group of noncalcareous agricultural soils. The soils were collected from 19 states in the southeast, north central, and northeast regions of the United States. In general, good relationships were obtained when soils were grouped according to geographic location. All soil tests were good predictors of labile P for the north central soils and for soils from Ohio and Pennsylvania (r2 ≥ 0.92). On the southeastern soils, the best relationships were found between labile P and the Olsen and Mehlich I soil test P measurements (r2 ≥ 0.90) after further separation of the soils into textural groups. Good relationships were found between EPC and the three soil test P measurements for the north central soils (r2 ≥ 0.80) and for the southeastern soils (r2 ≥ 0.71). For the soils from Pennsylvania and Ohio, Bray‐1 was the best predictor of EPC (r2 = 0.94). The relationships between algae‐available P and the soil test P and labile P measurements varied with the “active” Fe and Al content of the soils, although significant relationships between the parameters were developed for the north central soils (r2 ≥ 0.71) and for the southeastern soils separated into groups of low and high active Al contents (r2 ≥ 0.67).
Nutrient Runoff Losses as Predicted by Annual and Monthly Soil Sampling
Authors: Sharpley A. N. , Smith S. J. , Berg W. A. , Williams J. R. 
Published: July 2010

AbstractThe transport of soluble and particulate P and N in runoff from several cropped and grassed watersheds in Oklahoma and Texas was related to the nutrient content of surface soil (0–50 mm) sampled monthly and annually (March) over a 2‐yr period in an effort to improve the prediction of nutrient transport. For both monthly and annual soil samplings, the prediction of soluble P was good for events > 0.75 mm runoff (r values ranged from 0.57 to 0.92), but smaller events were poorly predicted. The nitrate content of runoff was not closely related to surface soil content (r vlaues ranged from 0.17 to 0.58), precluding its accurate prediction in runoff. Prediction of both particulate P and total N concentrations of individual runoff events was improved using separate equations for grassed and cropped watersheds compared to a general equation. Even so, predicted mean annual flow‐weighted concentrations and amounts of soluble P, particulate P, and total N using either monthly or annual soil nutrient data were significantly related to measured values at the 0.01 level and above (r values ranged from 0.57 to 0.97). Results indicate that seasonal variation in soil nutrient content had less effect on the predictive equations than rainfall and management characteristics. Consequently, these characteristics must be accounted for before the transport equations can be reliably used on an individual runoff event basis.
Reduction of Hexavalent Chromium in Water Samples Acidified for Preservation
Authors: Stollenwerk K. G. , Grove D. B. 
Published: July 2010

AbstractReduction of hexavalent chromium, Cr(VI), in water samples, preserved by standard techniques, was investigated. The standard preservation technique for water samples that are to be analyzed for Cr(VI) consists of filtration through a 0.45‐µm membrane, acidification to a pH < 2, and storage in plastic bottles. Batch experiments were conducted to evaluate the effect of H+ concentration, NO2, temperature, and dissolved organic carbon (DOC) on the reduction of Cr(VI) to Cr(III). The rate of reduction of Cr(VI) to Cr(III) increased with increasing NO2, DOC, H+, and temperature. Reduction of Cr(VI) by organic matter occurred in some samples even though the samples were unacidified. Reduction of Cr(VI) is inhibited to an extent by storing the sample at 4°C. Stability of Cr(VI) in water is variable and depends on the other constituents present in the sample. Water samples collected for the determination of Cr(VI) should be filtered (0.45‐µm membrane), refrigerated, and analyzed as quickly as possible. Water samples should not be acidified. Measurement of total Cr in addition to Cr(VI) can serve as a check for Cr(VI) reduction. If total Cr is greater than Cr(VI), the possibility that Cr(VI) reduction has occurred needs to be considered.
Combined Effects of Peroxyacetyl Nitrate and Ozone on Growth of Four Tomato Cultivars
Authors: Temple P. J. , Taylor O. C. 
Published: July 2010

AbstractIn a greenhouse exposure chamber study to determine the combined effects of peroxyacetyl nitrate (PAN) and ozone (O3) on foliar injury and growth of four cultivars of tomato (Lycopersicon spp.), 4‐week‐old plants were exposed to 0, 125, and 250 µg m−3 PAN and 0, 200, and 400 µg m−3 O3, and all combinations, 4 h/d, once per week for 3 weeks. Plants were harvested 1 week after the last exposure. The experiment was repeated twice. Ozone induced trace (ca. 1%) foliar injury at 200 µg m−3 and moderate (30–50%) foliar injury at 400 µg m−3. Peroxyacetyl nitrate caused no foliar injury development, either alone or in combination with O3, and had no effect on O3 injury. Foliar injury on the four cultivars increased in the order ‘Heinz 1350,’ ‘Tiny Tim,’ ‘Ace,’ and ‘Pyxie.’ Ozone by itself produced a significant linear reduction in growth of the four cultivars. Plants exposed to PAN alone also showed reduced growth but results were not statistically significant at the 0.05 level. Combinations of O3 and PAN had less than additive effects on growth reduction, but greater than additive effects on shoot/root ratios. This difference was attributed to greater suppression of root growth relative to leaf growth induced by O3‐PAN mixtures.
Plant Uptake of Heavy Metals in Zinc Fertilizers Made From Industrial By‐Products
Authors: Mortvedt J. J. 
Published: July 2010

AbstractMany industrial by‐products are being marketed as micronutrient fertilizers because of regulations which restrict indiscriminate disposal of wastes. Some of these materials contain other heavy metals which might be absorbed by crops and thus possibly enter the human food chain. Two greenhouse pot experiments were conducted to determine if corn (Zea mays L.) and Swiss chard (Beta vulgaris L.) absorbed significant quantities of Cd, Ni, and Pb from Zn fertilizers prepared from industrial by‐products. Corn forage yields increased with Zn applications on alkaline (pH 7.4) but not on acid (pH 5.8) Mountview silt loam (Typic Paleudults). Concentrations of Cd in immature corn forage were not affected by applications of Zn fertilizers containing from 1 to 2165 mg kg−1 of Cd. Dry matter yields of several harvests of Swiss chard were not affected by Zn applications at either soil pH level. Zinc concentrations in plant tissue increased with Zn applications but were lower in both crops grown on alkaline soil than in those grown on acid soil. Plant uptake of Cd generally increased with increasing levels of Cd in the Zn fertilizers on the acid soil only, with some concentrations > 2 mg kg−1 in chard tissue grown on acid soil. Uptake of Ni and Pb by both crops generally was not affected, even with Ni and Pb levels in some by‐products as high as 8950 mg kg−1 and 52 000 mg kg−1, respectively. These results suggest that plant uptake of heavy metal contaminants in Zn fertilizers made from some industrial by‐products is minimal, except for Cd in some leafy vegetables grown on acid soils. Since corn and most vegetable crops usually are not fertilized with Zn if grown on acid soils, plant uptake of heavy metal contaminants in by‐product Zn fertilizers should not be a significant problem.
Ozone and Sulfur Dioxide Effects on Tall Fescue: II. Alteration of Quality Constituents
Authors: Flagler R. B. , Youngner V. B. 
Published: July 2010

AbstractA greenhouse study was conducted to determine whether ozone (O3) and sulfur dioxide (SO2) might alter forage quality parameters of tall fescue (Festuca arundinacea Schreb. ‘Alta’). Plants were exposed weekly to four O3 treatments, 0, 0.10, 0.20, and 0.30 µL L−1; with or without 0.10 µL L−1 SO2, 6 h d−1 for 12 weeks. Ozone had a much greater impact on forage quality than did SO2. Ozone increased protein content on a g kg−1 basis and decreased protein on a weight per plant basis. Ozone reduced crude fat, crude fiber, and total nonstructural carbohydrate contents of the forage. Crude ash content increased due to O3 exposure. On a weight per plant basis, O3 decreased the forage concentration of Ca, Mg, and P. Ozone increased Ca concentration of herbage. Sulfur dioxide increased ash content of the forage. Phosphorus concentration and weight per plant of Mg and P were all reduced by SO2. Significant pollutant interactions occurred for crude fiber, crude ash, total Mg, and total P contents of forage. While treatments resulted in some apparent increases in forage quality, these were at the expense of yield. The most adverse effects on forage quality were an increase in ash content which resulted from an interaction of SO2 with O3, and a reduction in soluble carbohydrate content of shoots due to O3.
Riparian Losses of Nitrate from Agricultural Drainage Waters
Authors: Jacobs T. C. , Gilliam J. W. 
Published: July 2010

AbstractIncreased nutrient levels in surface streams and eutrophication of some Coastal Plain waters has led to inquiries about both the amount and control of nitrate losses from agricultural fields. Nitrate concentrations in shallow groundwaters beneath cultivated fields and in the drainage waters from those fields were examined to determine the fate of nitrogen lost to drainage waters. From a Middle Coastal Plain watershed where well‐ and moderately well‐drained soils dominate agricultural fields, 10 to 55 kg ha−1 yr−1 NO3‐N moved from the fields in subsurface drainage water. However, most fields are bordered by forested buffers between the cultivated areas and streams which consist of poorly and very poorly‐drained soils covered by dense vegetation. The evidence strongly indicated that a substantial part of the nitrate in the drainage water was denitrified in the buffer strip and that assimilation by vegetation was insignificant. Buffer strips of < 16 m were effective for inducing significant losses of nitrate before drainage water reached the stream. A field containing subsurface drainage tubing which emptied into open ditches moved more nitrogen into surface water than those fields without subsurface drainage improvements. From a Lower Coastal Plain watershed, a dense clay layer below the surface horizon reduced subsurface drainage resulting in total losses from the field of only 6 to 12 kg ha−1 yr−1 NO3‐N. These losses were mostly in surface runoff. The extensive floodplain of the natural stream had a high capacity to reduce large quantities of N but the low total loss from the watershed is largely a result of low input to the drainage water from nonpoint sources. Soils included in this study were Typic Paleudults, Arenic Paleudults, Aquic Hapludults, and Aeric Paleaquults.
The Effect of Nitrilotriacetic Acid on the Solubilities of Metals in Soil‐Sludge Mixtures
Authors: Garnett K. , Kirk P. W. W. , Lester J. N. , Perry R. 
Published: July 2010

AbstractBatch experiments were undertaken to determine the effect of nitrilotriacetic acid (NTA) on the solubilities of Cu, Mn, Ni, Pb, and Zn in soil/sludge mixtures. Soil samples from Wye Coombe series (silt‐loam, Rendolic Eutrochrepts) and Essex Windsor series (clay‐loam, Haplaquepts) were each mixed with anaerobically digested sewage sludge and the influence of extraction time, NTA concentration, and pH on the solubility of NTA and metals was assessed. Removal of NTA from the liquid phase by soil/sludge colloids became constant after 8 h and was attributed to adsorption. The concentration of soluble Ni, Pb, and Zn increased in both soil/sludge mixtures with increases in NTA concentration from 0 to 0.212 mmol L−1. Manganese was the least affected by the addition of NTA, and pH was shown to be the overriding influence on its solubility. In the Essex soil/sludge mixture, increasing the NTA concentration from 0 to 0.005 mmol L−1 caused a sharp decrease in Cu solubility, with higher NTA concentrations having no further effect on soluble Cu levels. Addition of NTA did not significantly change Cu solubility in the Wye soil/sludge mixture. These results provide a basis to design further experiments to determine if increased heavy metal solubility could result if sludge containing NTA was applied to agricultural land.
Picloram Movement in an Appalachian Hardwood Forest Watershed
Authors: Neary D. G. , Bush P. B. , Douglass J. E. , Todd R. L. 
Published: July 2010

AbstractPicloram (4‐amino‐3,5,6‐trichloropicolinic acid) was applied at a rate of 5.0 kg ha−1 acid equivalent to 4 ha of the 28‐ha Watershed 19, Coweeta Hydrologic Laboratory in western North Carolina. The herbicide was broadcast manually as a pellet formulation (10% acid equivalent) in May 1978. The objective was to eliminate a poor‐quality mixed oak overstory and rhododendron (Rhododendron maximum L.)‐laurel (Kalmia latifolia L.) understory prior to planting white pine (Pinus strobus L.). Picloram residues in samples from an Umbric Dystrochrept soil peaked in concentration in the upper 0.07 m at 11.58 mg kg−1, had a half‐life of about 4 weeks, and declined to near detection limits 28 weeks after application. Soil solution contained the highest picloram levels at 0.6 m (peak of 350 mg m−3). Picloram residues were detected in soil solution 1.2 m into the soil, but concentrations were < 25 mg m−3, and persisted for only 60 weeks. Intensive sampling of two springs detected trace levels for a period of 18 d. Only sporadic, low‐level picloram residues were detected in streamflow from nested 10‐ha and 28‐ha watersheds during a 70‐week period. Use of the herbicide picloram did not affect the quality of streamflow from Watershed 19 for domestic or agricultural purposes.
Simulated Regional Variations in Pesticide Runoff
Authors: Haith Douglas A. 
Published: July 2010

AbstractMathematical models for daily weather, hydrology, and soil chemistry were combined in a general approach for estimating pesticide runoff. Runoff losses of atrazine [2‐chloro‐4(ethylamino)‐6‐(isopropylamino)‐s‐triazine] and carbofuran (2,3‐dihydro‐2,2‐dimethyl‐7‐benzofuranyl methylcarbamate) were simulated for hypothetical 9‐ha corn (Zea mays L.) fields in New York, Georgia, Iowa, Texas, and Kentucky. Two representative soils were considered: a well‐drained sandy loam and a poorly‐drained silty clay loam exemplified by a Typic Dystrochrept and Typic Albaqualf, respectively. The two pesticides, five locations, and two soils produced a total of 20 cases. Each case was simulated for 100 yr by a Monte Carlo process to produce 100 samples of annual pesticide runoff. Mean annual pesticide losses ranged from 0.7 to 6.3% of application for atrazine and from 0.8 to 11.4% for carbofuran. Statistical analyses of the samples indicated that soil type affects pesticide runoff, with the silty‐clay loam producing significantly greater losses than the sandy loam. Regional similarities and differences were also identified. New York pesticide losses were significantly lower than those from the other four sites. Conversely pesticide runoff values from Georgia and Texas were statistically similar. Variations in pesticide runoff are largely explained by seasonal runoff volume. Regressions on mean runoff volume during the month of pesticide application explained over 89% of the observed variation in mean annual pesticide in runoff.
Effects of a Glucose‐imposed Oxygen Demand on Land Treatment Systems
Authors: Coody Peter N. , Sommers Lee E. , Nelson Darrell W. 
Published: July 2010

AbstractLaboratory experiments were conducted to quantify soil and crop interactions in a land treatment system receiving a glucose‐imposed oxygen demand. Synthetic wastewaters were prepared by dissolving sufficient glucose in a plant nutrient solution to provide four levels of chemical oxygen demand (COD). The solutions were applied to soil columns cropped to reed canarygrass (Phalaris arundinacea L.) to provide a COD of 0 to 180 mmol O2 column−1 week−1. The columns received the glucose for 25 weeks and were monitored for the composition of the soil atmosphere, plant yields, water use, and COD removal. The added COD elevated CO2 concentrations in the soil atmosphere to over 480 times atmospheric levels. This coincided with a depletion of O2 in the soil atmosphere, where a minimum concentration of 0.3 mol O2 m−3 was observed. Average plant yields ranged from 2.8 to 20.3 g column−1 and were inversely proportional to the COD added. Water use ranged from 11.4 to 26.9 cm column−1 week−1 and was directly related to the reduction in plant growth caused by the COD loading. Greater than 97% of the added COD was removed by the simulated land treatment system.
Response of Soybean to Low Concentrations of Ozone: I. Reductions in Leaf and Whole Plant Net Photosynthesis and Leaf Chlorophyll Content
Authors: Reich P. B. , Schoettle A. W. , Raba R. M. , Amundson R. G. 
Published: July 2010

AbstractSince most commercially grown soybean plants in the USA are subjected to low or moderate levels of ambient O3 pollution it is important to understand whether exposure to O3 influences CO2 exchange in this species. Therefore, for 8 weeks soybean (Glycine max cv. Hodgson) plants were exposed to O3 for 6.8 h daily in controlled environment chambers. Four treatments were used: 0.01, 0.05, 0.09, and 0.13 µL L−1 O3 in filtered air. Net photosynthesis (Pn), dark respiration, and chlorophyll content were measured in all treatments for both individual leaves of various ages and for whole plants. Measurements of CO2 exchange were made nondestructively with an infrared gas analysis system using either plexiglass cuvettes (leaves) or continuously stirred tank reactors (plants). The Pn of whole plants was reduced by 10, 11, and 22% in the 0.05, 0.09, and 0.13 µL L−1 treatments, respectively, compared with the 0.01 µL L−1 treatment. Among individual leaves of similar ages, exposure to O3 also resulted in declines in Pn and this occurred at all leaf ages. There was a significant linear relationship between Pn and O3 concentration for both individual leaves and for whole plants. Chlorophyll contents of whole plants and individual leaves were also reduced by O3 exposure. Chlorophyll content and Pn were correlated with each other for both individual leaves and whole plants. Changes with leaf age were typical for Pn and for chlorophyll content. There was no apparent effect of O3 treatment on dark respiration. The observed reduction in Pn at low levels of O3 (coupled with reports of O3‐induced reduction in growth and yield) suggests that ambient O3 pollution in the USA is currently causing decreased Pn in field‐grown soybean which can lead to a significant loss in yield.
Sewage Sludge as a Coal Mine Spoil Amendment for Revegetation in Colorado
Authors: Topper K. F. , Sabey B. R. 
Published: July 2010

AbstractUse of digested municipal sewage sludge as an amendment for revegetation of a Colorado coal mine spoil was evaluated as a function of application rate. Plant growth responses to sewage sludge additions were compared to inorganic nitrogen (N) and phosphorus (P) fertilizer treatments on a grass pasture mixture. Sewage sludge additions resulted in significant increases in aboveground biomass and percent canopy cover over the control for two seasons of growth following sludge application. Sewage sludge rates < 83 Mg ha−1 yielded greater plant growth than any of the inorganic N and P fertilizer treatments for both growing seasons. However, the lowest level of sewage sludge (14 Mg ha−1) resulted in equivalent total N and total P concentrations of the seeded grasses when compared to the highest inorganic fertilizer treatments. The superior growth associated with sewage sludge additions at less than 83 Mg ha−1 was likely due to measured increases in nutrient availability, improved physical condition of the spoil and a possible stimulation of microbial activity. The highest level of sewage sludge (83 Mg ha−1) was detrimental to seeded grass growth when compared to the lower sludge rates in 1984. This may have been due to increased soluble salt concentrations, an increase in competition by invading annual forbs, and/or elemental toxicities. Further research is necessary to determine the exact causes.
Forms of Solid Phase Copper in Copper‐enriched Swine Manure
Authors: Miller W. P. , Martens D. C. , Zelazny L. W. , Kornegay E. T. 
Published: July 2010

AbstractManure from swine fed high levels of copper (Cu) was extracted sequentially and nonsequentially with reagents designed to selectively solubilize specific Cu forms from the manure. Fresh (slurry), freeze‐dried, and oven‐dried samples were used. Water‐soluble Cu increased from 2% to 30% with increasing severity of drying. Salt solutions [calcium (Ca) and lead (Pb)] were no more effective than H2O in extracting Cu, suggesting both a lack of Cu adsorbed on inorganic mineral surfaces (which were composed largely of quartz, calcite, and gypsum), and a strong binding of the Cu against Pb‐exchange, presumably with organic material. Dilute acetic acid (pH 2.5) removed 67% of the Cu from oven‐dried samples, but only 7 to 11% from the slurry or freeze‐dried samples. This suggests that Cu oxide and hydroxide minerals, which are soluble in this reagent, were not present in the fresh, slurried manure, but that oven‐drying of the manure affects chemical forms of Cu in a significant fashion. Most of the Cu in all the manure samples was extractable with sodium hydroxide (NaOH) or potassium pyrophosphate (K4P2O7), suggesting association with organics. Little Cu remained after sequential K4P2O7 extraction, at which point CuS minerals would be expected to remain in the residue. It was concluded that Cu minerals are probably not found in this waste, but that most, if not all, of the Cu is associated with the organic fraction.