bluuebunny/crossref_metadata_2025_split huggingface dataset:
Removal of Paraquat, Diquat, and Amitrole from Aqueous Solution by Chemically Modified Peat
Authors: Mac Carthy Patrick , Djebbar K. E. 
Published: July 2010

AbstractThe presence of organic pesticides in aquatic systems has been reported for more than 40 yr. Various methods, such as sorption by clays, activated C, or synthetic resins, have been used to remove these pesticides from water. Certain pesticides, such as the cationic species paraquat (C12H14N2Ch2; 1,1′‐dimethyl‐4,4′‐bipyridinium dichloride), diquat (C12H12N2Br2; 6,7‐dihydrodipyrido[1,2‐a:2′,1′‐c]pyrazinediium dibromide), and the basic species amitrole (C2H4N4; 3‐amino‐s‐triazole), are sorbed by peat. However, the use of raw peat as a sorption medium for the removal of pesticides is hampered by the relative impermeability of peat, the leaching of organic matter from peat into the effluent, and by the disaggregation of peat at pH values greater than ca. 6.0. Treatment of peat with concentrated sulfuric acid at elevated temperatures yields a granular product that has an enhanced cation exchange capacity, that is resistant to leaching, and is permeable to water flow. The objective of this research was to evaluate the use of such chemically‐modified peat for removing paraquat, diquat, and amitrole from aqueous solution under a variety of experimental conditions. Using isotherm and column experiments, it was shown that the treated peat is very effective in removing these pesticides from aqueous solution. Treated peat has a capacity of about 1 mol (+) kg−1 for these three pesticides. The effects of pH, ionic strength, and flow rate on the efficiency of pesticide removal were found to be relatively small. Peats from two different localities behaved similarly in these experiments.
Permethrin Washoff from Cotton Plants by Simulated Rainfall
Authors: Willis G. H. , Mc Dowell L. L. , Smith S. , Southwick L. M. 
Published: July 2010

AbstractDeveloping models for predicting amounts of pesticide transported in runoff and suspended sediment from agricultural land to aquatic. habitats has been hampered for foliarly‐applied pesticides by a lack of knowledge about the processes of pesticide washoff from plants by rainfall. A multiple‐intensity rainfall simulator was used to determine the effects of rain intensity and amount on permethrin [(3‐phenoxyphenyl) methyl (±)‐cis, trans‐3‐(2,2‐dichloroethenyl)‐2,2‐dimethylcyclopropanecarboxylate] concentrations and amounts washed from mature cotton (Gossypium hirsutum L.) plants. Permethrin concentration in plant washoff was independent of rain intensity when 25 mm of simulated rain was applied at 6.6, 13.0, 25.7, and 51.3 mm h−1 2 h after permethrin was applied at 0.224 kg ha−1. Concentrations were less when the same amount of simulated rain was applied at 106.4 mm h−1. Permethrin concentrations in plant washoff decreased rapidly during the early phases of washoff. About 35% of the permethrin load on the plants 2 h after application was washed off by 25 mm of rain; an additional 76 mm of rain removed only 11% more of the permethrin from the plants. Rainfall amount had greater influence than rainfall intensity on the amount of permethrin washed from the cotton plants. This information greatly simplifies modeling the movement of permethrin from the plant canopy to soil during natural storms when intensities vary greatly within storms and from storm to storm.
Evaluation of Nitrogen Availability Indexes for a Sludge Compost Amended Soil
Authors: O'Keefe Barry E. , Axley J. , Meisinger J. J. 
Published: July 2010

AbstractSeveral N availability methods were evaluated on a sludge amended soil, since sludge applications are usually based on N availability and a soil N evaluation to optimize loading rates. Yearly amendments of composted, lime‐stabilized, raw sludge were applied, at 0, 56, 112, and 224 Mg ha−1, to an Elkton silt loam soil (Typic Ochraquults), in Beltsville, MD, as follows: whole plots (1975–1977), half plots (1978), and no plots (1979–1981). In 1978 and 1981, surface and subsurface soil samples were collected and maize (Zea mays L.) total N uptake was determined. The biological method (73‐week aerobic incubation [NT]) of assessing soil N availability revealed an initial rapid miner. alization phase (NE) over the first 28 weeks and a constant phase thereafter. The chemical methods were total soil N (TN), acid KMnO4 oxidizable N (P), autoclave extractable N (A), and 2 M KCl extractable NH+4‐N (K). Curvilinear regression analyses relaling maize N uptake to these N indexes gave the following R2 values: NE, 0.93; NT, 0.94; TN, 0.93; P, 0.92; A, 0.95; and K, 0.92. All methods were equally sensitive on sludge treated soils; however, the incubation procedure was best on untreated soil. Including second zone soil N and expressing the results on a root‐zone volume basis improved N uptake predictions with unfertilized controls, but was unnecessary for sludge treated plots. These results indicate that chemical N availability indexes can be used to assess soil N availability on sludge treated land; provided they are calibrated to local soil‐crop‐climate conditions.
Prediction of Available Zinc in Sewage Sludge‐amended Soils
Authors: Rappaport B. D. , Martens D. C. , Simpson T. W. , Reneau R. B. 
Published: July 2010

AbstractA routine soil test would be helpful for management of agricultural soils amended with sewage sludge high in Zn. Fourteen field sites were selected in the Coastal Plain, Piedmont, and Ridge and Valley regions of Virginia to evaluate the suitability of the dilute HCl‐H2SO4 and DTPA soil extractants for prediction of Zn uptake by corn (Zea mays L.). Soil and corn tissue samples were collected from these sites where sewage sludge had been applied previously. Multiple regression analysis was used to assess the forms of soil Zn extracted by dilute HCl‐H2SO4 and DTPA. The exchangeable and specifically sorbed, organically bound and noncrystalline hydroxide and oxide bound Zn fractions were tested to develop equations. Dilute HCl‐H2SO4 extracts were related to the three Zn fractions (R2 = 0.98**), whereas organically bound Zn was the only Zn fraction related to DTPA‐extractable Zn (r = 0.96**). Earleaf Zn concentration correlated more closely with DTPA‐extractable Zn (r = 0.64*) than with dilute HCl‐H2SO4‐extractable Zn (r = 0.35). The earleaf Zn concentration was studied as a function of either DTPA‐ or dilute HCl‐H2SO4‐extractable Zn, exchangeable and specifically sorbed Zn, organically bound Zn, and noncrystalline hydroxide and oxide bound Zn. Inclusion of the above fractions in a multiple regression analysis did not improve the relationship between earleaf Zn concentration and dilute HCl‐H2SO4‐extractable Zn. A coefficient of multiple determination (R2 = 0.77**) was obtained between earleaf Zn concentration and a two variable regression equation comprised of DTPA‐extractable Zn and organically bound Zn. The negative regression coefficient for organically bound Zn indicated that a portion of this fraction, which was extracted by the DTPA, did not supply Zn to corn plants.
Chemical Composition of Vegetables Grown on an Agricultural Soil Amended with Sewage Sludges
Authors: Keefer R. F. , Singh R. N. , Horvath D. J. 
Published: July 2010

AbstractHeavy metals were analyzed in edible and nonconsumable parts of radish (Raphanus sativus L. cv. White Icicle), carrots (Daucus carota cv. Chantenay), cabbage (Brassica oleracea var. capitata L. cv. Market Topper), green beans (Phaseolus vulgaris cv. Tenderette), sweet corn (Zea mays L. rugosa cv. Silver Queen), and tomatoes (Lycopersicon esculentum cv. West Virginia '63) grown on a sandy loam soil to which four sewage sludges were applied in the field at 90 and 180 Mg ha−1. Cadmium, Cr, and Pb concentrations in the edible parts of the vegetables from sludge treated plots were no more than 1.0 mg kg−1 above those from the untreated control plots. However, considerably more of these elements accumulated in radish tops, bean leaves, and corn leaves grown on a soil treated with two of the sludges. Nickel concentrations in vegetables from plots receiving two of the sludges were significantly higher than in the controls for both edible and nonconsumable parts of most of the vegetables grown. More Ni was absorbed by vegetables grown on a plot treated with sludge which was relatively low in total Ni (270 mg kg−1) than with a sludge which contained more than 47 times as much total Ni. Copper and Zn levels in vegetables grown on some sludge‐treated soils were elevated; however, these were not so high to cause alarm. The results emphasize the need for more information about sewage sludge than just total elemental analyses prior to application onto land on which vegetables will be grown.
A One‐dimensional Model of Chemical Diffusion and Sorption in Saturated Soil and Aquatic Systems
Authors: Corwin D. L. 
Published: July 2010

AbstractA one‐dimensional model for chemical diffusion in saturated porous media systems is presented. The one‐dimensional diffusion model provides for adsorpfion‐desorption reactions either Freundlich or Langmuir, and both solid and liquid phase first‐order chemical degradation under isothermal, water‐saturated conditions. Finite‐difference solutions to the model which simulate the one‐dimensional diffusion of an inorganic/organic chemical from the sediment of an aquatic system into the overlying water are provided for a variety of initial and boundary conditions. Analogous applications to flow processes within a slructured soil can be made for the diffusion of an inorganic/organic chemical into and out of saturated planar soil aggregates. The initial and boundary conditions are designed to simulate a variety of aquatic situations: ponds, lakes, streams, rivers and oceans. Both explicit and implicit (i.e., Crank‐Nicolson) finite‐difference schemes are presented for four different saturated systems. The model provides a means of assessing the physicoehemical dynamics of chemical‐sediment‐water interactions and of assessing the pollution potential of chemicals to plants and animals as determined by their propensity to migrate to different compartments of the aquatic environment. The models can also determine the influence of diffusion processes within planar soil aggregates upon solute flow in saturated structured soils. Various simulations are presented for boron (B), diquat (1,1′‐ethylene‐2,2′‐dipyridilium dibromide), and bromacil (5‐bromo‐3‐sec‐butyl‐6‐methyluracil).
Proton and Metal Complexation by Water‐soluble Ligands Extracted from Anaerobically Digested Sewage Sludge
Authors: Baham John , Sposito Garrison 
Published: July 2010

AbstractA water‐soluble extract (WSE) of an anaerobically‐digested sewage sludge containing 19.5 mol m−3 (19.5 mM) total soluble carbon (CTS) was acidified to pH 3 and titrated with NaOH to pH 11 in a 50 mol m−3 (50 mM) NaClO4 background at 25°C. Conditional protonation constants were determined from the formation function computed from the titration data. The common logarithms of the average protonation constants for functional groups titrated between pH 3 and 11 were 4.2, 7.2, and 9.6. Trace metal‐WSE complexes were chromatograpbed on a molecular size exclusion gel. Copper formed the more stable complexes with the ligands in the WSE when compared to Ni or Cd. Cadmium was present predominately as the free metal ion or in inorganic complexes. Adsorption of Cu by montmorillonite was significantly reduced in the presence of the WSE. Since most of the organic carbon present in the WSE remained in solution during the adsorption experiments, the primary factor controlling Cu solubility was concluded to be the formation of soluble organo‐Cu complexes. A “mixture model” was developed to simulate qualitatively the proton binding of the inorganic and organic components of the WSE. This model included organic and inorganic ligands whose relative concentrations were previously analytically determined for the WSE. The “mixture model” ligands were employed to model Ca and Cd speciation for gel filtration and adsorption experiments. The “mixture model” qualitatively explained the observed speciation in both experiments.
Crop Yield Response Predicted with Different Characterizations of the Same Ozone Treatments
Authors: Cure William W. , Sanders John S. , Heagle Allen S. 
Published: July 2010

AbstractData were obtained from three field experiments studying the effects of chronic doses of ozone (O3) on crop yield. All used open‐top exposure chambers. Two were of the same design with soybean [Glycine max (L.) Merr.] in 1977 and 1978 and the third was with peanut (Arachis hypogaea L.) in 1980. Exposures had been conducted for 7 h each day starting shortly after crop emergence and ending with maturity. Each experiment included a treatment level below ambient, two at ambient levels, one within and one outside of a chamber, and two to three treatments at levels above ambient established by adding different but constant amounts of O3 to ambient air. Three different characterizations of each O3 treatment were compared as independent variables in simple linear O3 dose‐yield response models. Ozone treatments were characterized as (i) the seasonal mean of the daily 7‐h means (“7‐h mean”), (ii) the seasonal mean of the daily maximum 1‐h mean concentrations (“1‐h mean”), and (iii) the seasonal maximum 1‐h mean concentration (1‐h max). The ratio of the 1‐h mean to 7‐h mean concentration in each treatment was very similar over the range of treatment levels in an experiment. Models of the same yield data developed with either seasonal mean could probably be used interchangeably by converting between concentration scales with a constant multiple. The relation between the 1‐h max concentration and either of the seasonal means changed with treatment level within an experiment and was different for similar treatments in different years. The range of yields predicted with models based on 1‐h max concentrations using the maximum and minimum ambient O3 concentrations in the 3 yr of these experiments was three to four times that obtained with either seasonal mean model.
Time‐dependent Leaching of Radium from Leaves and Soil
Authors: Simon Steven L. , Deming Elizabeth J. 
Published: July 2010

AbstractThe accumulation of Ra or other radionuclides in vegetation via root uptake depends on the availability and uptake rate from soil, in addition to the rate of loss from the leaves due to natural leaching processes. We conducted studies to determine the time‐dependent leachable fraction of 226Ra from soil as a function of time after soil spiking and the loss rate of internal 226Ra from leaves due to leaching by exposure to natural field conditions. The leachable fraction of Ra from spiked soil decreased exponentially over time to a value of 0.1% after approximately 28 d. The internal Ra activity in leaves decreased exponentially to 40% of the original activity after 1 yr of exposure to outdoor conditions in a semiarid environment. The relationship of these two phenomena to the accumulation of Ra in plants via root uptake is illustrated by the equilibrium solution of a first‐order differential equation.
Extractability and Plant Availability of Molybdenum from Inorganic and Sewage Sludge Sources
Authors: Pierzynski Gary M. , Jacobs Lee W. 
Published: July 2010

AbstractA greenhouse experiment was conducted to evaluate the influence of soil pH on the plant uptake and extractability of Mo applied to a soil as an inorganic salt and as a Mo‐enriched sewage sludge. Molybdenum additions of 30, 60, and 120 mg/kg soil from Na2MoO4·2H2O and 20, 44, and 94 mg/kg soil from an anaerobically digested sewage sludge significantly increased Mo concentrations in corn (Zea mays L.), soybeans [Glycine max (L.) Merr.], and alfalfa (Medicago sativa L.) grown on a sandy loam soil. Increases in soil pH significantly increased Mo accumulation in the three crops from both Mo sources. Molybdenum extracted with Tamm's acid ammonium oxalate was not significantly influenced by soil pH, while Mo extracted from sludge treated soils with the ammonium bicarbonate‐DTPA (AB‐DTPA) extractant was significantly increased with increasing soil pH. Multiple regressions between Mo concentrations in the crops and extractable Mo and soil pH indicated that soil pH was a significant variable in 17 of 24 prediction equations. The AB‐DTPA extractant was more effective in predicting Mo concentrations in plant tissue than Tamm's acid ammonium oxalate with sludge Mo additions and is more effective with sludge source Mo as compared to inorganic source Mo. Whether AB‐DTPA will predict Mo uptake by plants grown on soils receiving Mo additions needs to be tested by field evaluation with a large number of soil types.
Characteristics of Air Exclusion Systems vs. Chambers for Field Air Pollution Studies
Authors: Olszyk David M. , Kats Gerrit , Dawson Philip J. , Bytnerowicz Andrzej , Wolf Joanne , Thompson C. Ray 
Published: July 2010

AbstractAn air exclusion system was designed, constructed, and tested to determine its effectiveness in studies of air pollutant effects on vegetation. The air exclusion system was shown to be an effective alternative to open‐top field chambers for controlled exposures of air pollutants to low growing plants. The system design included particulate and activated charcoal filters, pressure‐type blowers, a mixing manifold, and perforated inflatable ducts that were positioned between rows of plants. Tests with CO as a tracer gas indicated optimal system parameters for air exclusion including: air flow of at least 0.944 m3 s−1 within the ducts, three or four rows of holes on the side of each duct pointing 45° upward, 90° to the side, and 45° downward from the center of the duct, four ducts per system, and a hole size that provided an air velocity of 0.5 to 1.8 m s−1 over the plant canopy. Reductions of > 70% in ambient O3 concentrations could be achieved over the plant canopy at 0.25 m above the ground with the air exclusion system under optimum conditions (low ambient wind speed and high ambient ozone concentrations). This was comparable to the reductions achieved with either open‐top or closed‐top chambers. A gradient in ozone concentrations was obtained within a single system by delineating the ducts into three sections with different sized holes. Sulfur dioxide was added to a modified system to provide a gradient of 0, 0.03, 0.07, and 0.15 µL SO2 L−1 over a winter growing season. No large environmental differences were found between air exclusion systems and open‐top chambers vs. outside plots in the summer. In the fall and winter, open‐top chambers had higher air, leaf, and soil temperatures than air exclusion sytems or outside plots. Air speed over the plant canopy was higher with the air exclusion system than in open‐top chambers or outside plots.
Soil and Groundwater Salinity Along Drainage Ditches in Eastern North Dakota
Authors: Skarie R. L. , Richardson J. L. , Maianu A. , Clambey G. K. 
Published: July 2010

AbstractThe most severely affected saline soils in the Red River Valley of North Dakota are normally observed in linear patterns along shallow roadside drainage ditches. Although the affected areas tend to be small, taken as a group they represent a considerable loss of productivity. Research was conducted to study the relationship between soil salinity and groundwater hydrology adjacent to roadside drains. Data for groundwater depth, electrical conductivity, and chemistry indicated that significant seepage occurs from the ditches. During recharge periods, both depth and salinity of groundwater tended to increase with distance from the drain. Ratios of Ca2+ to Mg2+ and Na+ tended to decrease over the same distance. Maximum salinity of the soil surface was observed where groundwater was of intermediate depth and salinity for a given site. Soils near the drain were most saline at the surface, whereas soils beyond the influence of the ditch exhibited increasing salinity with depth. Seepage rates calculated from soil and groundwater parameters did not correlate with observed values of soil salinity for a given site. The degree of salinization appears more closely related to the frequency that surface water ponds in the drains. Pond permanence was inferred by wetland classification of the drains according to the plant species present.
Wastewater Renovation in a Slash Pine Plantation Subjected to Prescribed Burning
Authors: Red Jane T. , Nutter Wade L. 
Published: July 2010

AbstractTwo experimental areas were established in an underdrained 16‐yr‐old slash pine (Pinus elliottii Mor.) plantation land treatment system receiving 2.5 cm/week of secondarily treated domestic wastewater. One of the experimental areas was subjected to a prescribed burn as a forest management practice. A high degree of wastewater renovation was achieved and the prescribed burn had no significant effect on wastewater renovation. Forest floor storage of K, Ca, Mg, and P was significantly increased from pretreatment levels due to wastewater irrigation. Prescribed burning had no effect on forest floor nutrient storage. Soil concentrations of total and available P, Ca, Mg, and K increased significantly in the surface soil horizon due to wastewater irrigation. Additional increases in the surface soil horizon of total P, Ca, Mg, and K concentration occurred due to burning. Wastewater irrigation resulted in significant reductions in soil acidity and total‐Kjeldahl N concentration in the surface horizon. Prescribed burning altered species composition and density of the understory. No significant differences in overstory nutrient storage were observed due to treatment.
Effects of Sulfur Dioxide and Ambient Ozone on Winter Wheat and Lettuce
Authors: Olszyk David M. , Bytnerowicz Andrzej , Kats Gerrit , Dawson Philip J. , Wolf Joanne , Thompson C. Ray 
Published: July 2010

AbstractWinter wheat (Triticum aestivum L. ‘Yecora Rojo’) and lettuce (Lactuca saliva L. ‘Empire’) were exposed in the field to SO2 or ambient O3 to determine the effects of these air pollutants on important winter grown crops. Plants were exposed with tubular air exclusion systems or in open‐top field chambers to ambient air, or filtered air plus 0, 0.03, 0.07 or 0.15 µL SO2 L−1. Exposures were continuous from 18 Jan. to 7 May 1984 for wheat and from 18 Jan. to 13 Mar. 1984 for lettuce. Harvests to evaluate early plant growth were made after 2 to 3 weeks of exposure for each crop; final harvests were made at the end of the exposures. Wheat yield was decreased with exposure to 0.15 µL SO2 L−1 in open‐top field chambers, but was not affected by SO2 exposure in air exclusion systems. Lettuce yield was decreased with exposure to 0.15 µL SO2L−1 in air exclusion systems, but was not affected by SO2 exposure in open‐top chambers. Neither wheat nor lettuce yield was reduced by ambient O3 in either air exclusion systems or open‐top chambers. The results from the two types of exposure systems could not becompared statistically due to differences in experimental design and soil topography. However, the differences in plant growth between the two systems were dramatic when compared to outside plots. Wheat and lettuce growth and yield was only slightly greater with air exclusion systems than in outside plots, but much greater in open‐top field chambers than in outside plots.