bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leaching of Nitrogen, Phosphorus, and Organic Carbon from Wheat Straw Residues: I. Rainfall Intensity
Authors: Schreiber J. D. , Mc Dowell L. L. 
Published: July 2010

AbstractKnowledge of nutrients leached from crop residues will aid in understanding nutrient cycling in agricultural systems and in the development of small watershed chemical transport models. Using a multiple‐intensity rainfall simulator, wheat straw residue (Triticum aestivum L.) was subjected to 25.4 mm simulated rainfall at intensities of 7, 12, 25, 53, and 105 mm h−1. The wheat straw loading rate was 4500 kg ha−1. Runoff was sampled as a function of time and analyzed for PO43−‐P, NH4+‐N, NO3−‐N, and organic carbon (OC). Except for NO3−‐N, nutrient concentrations and losses were greater at the lower rainfall intensities. At each intensity, PO43−‐P, NH4+‐N, and OC concentrations in runoff from the wheat straw increased rapidly to maximum values and then decreased with time. After maximum nutrient concentrations were reached, a power function, Y = aXb, best described the relationship of nutrient concentrations with time, whereas a hyperbolic equation of the form Y = 1/(a + bX) best described the relationship of nutrient concentrations with runoff. The quantity (kg ha−1) of nutrients leached from the wheat straw followed the order C > P > N as (NH4+‐N + NO3−‐N). Amounts of N as (NH4+‐N + NO3−‐N) and C leached from the wheat straw were ≤ 1% of the nutrient content compared with 80 to 140 g kg−1 for P. This study also indicates that the variability in both the leachability and nutrient content of crop residues from different sources will be important, factors in the development of crop residue leaching models.
Leaching of Nitrogen, Phosphorus, and Organic Carbon From Wheat Straw Residues: II. Loading Rate
Authors: Schreiber J. D. 
Published: July 2010

AbstractUsing a rainfall simulator, wheat straw residue (Triticum aestivum L.) in 1.0‐m2 pans was subjected to simulated rainfall. Runoff from the wheat residue was sampled as a function of time and analyzed for PO43−‐P, NH4+‐N, NO3−‐N, and organic carbon (OC). Rainfall at 25 mm h−1 was applied for 1 h to five residue weights equivalent to field loading rates of 2200, 4500, 6700, 9000, and 11 200 kg ha−1. As loading rates increased from 2200 to 9000 kg ha−1, both concentrations and losses of PO43−‐P, NH43−‐N, and OC increased, whereas those of NO3−‐N decreased. During individual runoff events at all loading rates, PO43−‐P, NH4+‐N, and OC concentrations increased relatively rapidly to a maximum concentration in runoff and then decreased during the remainder of the 1‐h runoff event. The relationship of nutrient concentrations with time were described by a power function Y = aXb and to runoff by a hyperbolic equation of the form Y = 1/(a + bX). The quantity (kg ha−1) of nutrients leached from the wheat residue followed the order C > P > N. For all loading rates, percentage N (NH4+‐N + NO3−‐N) and C leached from the wheat residue was < 10 g kg−1, compared with 240 to 430 g kg−1 for P.
Tree Ring Response of White Oak to Climate and Air Pollution near the Ohio River Valley
Authors: Mc Clenahen J. R. , Dochinger L. S. 
Published: July 2010

AbstractWhite oak (Quercus alba L.) tree ring chronologies were compared among five sites representing an apparent gradient of industrial air pollution emitted from sources in a portion of the Ohio River Valley near the southern Ohio‐northern Kentucky border. Response functions relating standardized ring‐width indices with principal components of climate for sites nearest the industrial area exhibited a strong nonclimatic influence from 1930 to 1978, which did not appear at more remote sites or in the 30 yr before 1930. Response functions for the entire 1900–1978 period declined in reliability to predict indices from climate at sites near the pollution sources, as did the response function derived for the most remote site when used to predict indices at the other four sites. Evidence for nonclimatic influence on indices appeared at all sites between about 1950 and 1966. The altered patterns of tree ring response to climate add to a growing body of evidence for broad‐scale changes in tree growth in the Northeast that may be associated with air pollution.
Determining the Number and Size of Soil Aliquots for Assessing Particulate Contaminant Concentrations
Authors: Gilbert Richard O. , Doctor Pamela G. 
Published: July 2010

AbstractIn this paper the planning of radionuclide and other environmental contaminant studies is discussed. This discussion is based on a study of the relationship between soil aliquot size and the variability between aliquot 241Am concentrations. The study consisted of drawing multiple soil aliquots of size 1, 10, 25, 50, and 100 g from a large composite soil sample collected at a nuclear weapons testing area on the Nevada Text Site. These aliquots were then analyzed for 241Am. The between aliquot standard deviation (s) of the data increased ninefold as aliquot size declined from 100 to 1 g. This implies that about 70 times as many 1‐g aliquots than 100‐g aliquots would be needed to achieve the same precision in the estimated mean of a single field sample. The data suggest a linear relationship between logarithms of s and aliquot weight (w). This relationship is used to determine the optimum w and number, n, of aliquots per field sample that should be used. These results are also extended to a second contaminant (239,240Pu in this case) that is in a ratio relationship to 241Am. Also, an approach is given for obtaining optimum numbers of field samples and number of aliquots per field sample to minimize either total sampling and analysis costs or the variance of the estimated mean. The aliquot data from the 241Am study indicate increasing median and geometric mean concentrations with increasing aliquot size. This happens because as aliquot weight increases there is a decrease in skewness of the frequency distribution of aliquot concentrations. Since the arithmetic mean is not affected (on the average) by a change in skewness, it may be preferred to the geometric mean or median when comparing results from studies that have used different aliquot sizes.
Biogeochemistry of Lead in McDonalds Branch Watershed, New Jersey Pine Barrens
Authors: Turner R. S. , Johnson A. H. , Wang D. 
Published: July 2010

AbstractLead concentrations, fluxes, and storage were measured in the vegetation, forest floor, and acid, sandy mineral soil (Quartzipsamments) of a forested watershed in the New Jersey Pine Barrens. Atmospherically deposited Pb at the McDonalds Branch Watershed was 140 g ha−1 yr−1 (8 µg L−1 in bulk precipitation) in 1980 to 1982, a substantial reduction from 350 g ha−1 yr−1 (17 µg L−1 in bulk precipitation) in 1978 to 1979. Virtually all Pb falling on the uplands was retained—75% by the organic forest floor and 25% by mineral soils, especially in B and C soil horizons. Total Pb content of the forest floor was 7.6 kg ha−1, with an accumulation rate of 100 g ha−1 yr−1 (1980–1982), or 1.3% of the forest floor pool. Estimated mean residence time of Pb in the forest floor was 220 yr. About 35 g Pb ha−1 yr−1 moved out of the forest floor in solution through the E horizon and was correlated strongly with dissolved organic matter. Approximately 30 g Pb ha−1 yr−1 accumulated in the B and C soil horizons. Less than 1 g Pb ha−1 yr−1 percolated past a depth of 2 m. Lowland muck soils and vegetation accumulated 98% of incoming Pb, with only 3.2 g Pb ha−1 yr−1 exported in the stream. Lead concentrations in the stream were correlated positively with dissolved organic matter and water level in the swamps. Lead in biota was contained mainly in the bark, fine roots, and foliage. Concentrations were: fine roots (18 mg kg−1) > bark (15 mg kg−1) > foliage (4 mg kg−1) > wood (0.5 mg kg−1). Although Pb concentrations in herbs, mosses, and lichens ranged from 10 to 60 mg kg−1, these plants accounted for very little biomass. Total Pb content of biota was 335 g ha−1, about 4% of the forest floor Pb content.
Biogeochemistry of Aluminum in McDonalds Branch Watershed, New Jersey Pine Barrens
Authors: Turner R. S. , Johnson A. H. , Wang D. 
Published: July 2010

AbstractAluminum concentrations, fluxes, and storage were measured in the vegetation, forest floor, and acid, sandy mineral soil of a forested watershed in the New Jersey Pine Barrens. Volume‐weighted mean Al concentrations in solution increased as water passed through the upland ecosystem, from 0.012 mg L−1 in bulk precipitation to 0.14 mg L−1 in throughfall to 0.45 mg L−1 in E horizon mineral soil, 0.60 mg L−1 in the B horizon, and 0.73 mg L−1 in the C horizon. Weighted mean Al concentration of the stream water was 0.15 mg L−1. Solution Al concentrations in different compartments of the ecosystem were related to the magnitude of moisture flux, dissolved organic carbon concentration, and pH. Soil solution and stream water Al concentrations were high in the winter and spring and low in the summer and fall, inversely following solution pH. Soil solution and stream pH were independent of precipitation pH because of internal control of H+ concentration by the soil and an apparent 0.5‐yr time lag in flushing of atmospherically deposited acids through the soil. Aluminum was partitioned strongly into the lower mineral soil horizons, but large stores of potentially labile Al were found in the upper mineral horizons and forest floor. Standing vegetation represented a relatively small pool of Al but cycled substantial amounts of Al between mineral soil and the forest floor.
Water Quality Effects of Clearcutting Upper Coastal Plain Loblolly Pine Plantations
Authors: Mc Clurkin D. C. , Duffy P. D. , Ursic S. J. , Nelson N. S. 
Published: July 2010

AbstractThe effect of clearcutting loblolly pine (Pinus taeda L.) on concentrations of sediment and nutrients in stormflows was studied on small catchments near Lexington, TN. The plantations were established on eroded and abandoned agricultural lands with fragile soils. Soil series on the catchments include Lexington silt loam (fine‐silty, mixed, thermic Typic Paleudalfs), Providence sill loam (fine‐silty, mixed, thermic Typic Fragiudalfs) and Ruston sandy loam (fine‐loamy, silicious, thermic Typic Paleudults). Eight catchments (0.17–0.56 ha) were instrumented with flumes equipped with water stage recorders to measure stormflow and Coshocton wheel samplers to obtain integrated samples of the flow. Plantations on four catchments were clearcut; the other four were left as uncut controls. Stormflow samples were analyzed for sediment‐phase total Kjeldahl nitrogen (TKN) and total phosphorus (TP) and solution‐phase TKN, TP, and potassium (K). Results indicated that a third or more of the TKN and two‐thirds of the TP exported in stormflow from the catchments was via sediment. Solution‐phase TKN and TP concentrations in stormflow were similar on clearcut and control catchments. Solution K concentrations were consistently higher from clearcut catchments. Rainfall inputs of TKN, TP, and K exceeded stormflow losses. The study demonstrated that pine plantations established on fragile soils can be clearcut without significant impact on water quality if recommended practices are used.
Reductive Dechlorination of the Pesticides 2,4‐D, 2,4,5‐T, and Pentachlorophenol in Anaerobic Sludges
Authors: Mikesell Mark D. , Boyd Stephen A. 
Published: July 2010

AbstractThe degradation of seven chlorinated aromatic compounds in anaerobic sewage sludge from three Michigan communities was examined. The compounds tested were 2,4‐D (2,4‐dichlorophenoxy acetic acid), 2,4,5‐T (2,4,5‐trichlorophenoxy acetic acid), PCP (pentachlorophenol), 2,4,6‐trichlorophenol, and 2‐, 3‐, and 4‐chlorophenol. All of the compounds tested were degraded in one or more of the sludges during a 70‐d incubation period. Overall, 4‐chlorophenol was the most persistent compound tested followed by 3‐chlorophenol. The most rapid degradative reactions were cleavage of the ether linkage of the phenoxy acetic acid herbicides 2,4‐D and 2,4,5‐T, and the removal of Cl atoms ortho to the phenolic OH group of the chlorophenols. The initial products of 2,4‐D and 2,4,5‐T degradation were 4‐chlorophenol and 2,4,5‐trichlorophenol. Reductive dechlorination of 2,4,5‐trichlorophenol (produced from 2,4,5‐T) gave 3,4‐dichlorophenol and 4‐chlorophenol which were the final products of 2,4,5‐T degradation. Dechlorination of PCP gave 3,4,5‐trichlorophenol as the initial transformation product, and further dechlorination gave 3,5‐dichlorophenol as the final product of PCP degradation. The Jackson sludge had the greatest capacity to degrade the compounds tested. With the exception of 3‐ and 4‐chlorophenol, all other compounds tested were completely degraded in 7 to 14 d in the Jackson sludge. Mason and Adrian sludges were similar in their degradative pathways overall, but significantly less active than the Jackson sludge.
Nutrient Returns from Field‐Drying of Logging Residue
Authors: Johnson James E. , Smith David W. , Stuart William B. 
Published: July 2010

AbstractIncreasing interest in utilizing logging residue for fuel has caused concern over additional nutrient removals from the site. On‐site drying of the residue may have an ameliorative effect due to nutrient returns during the drying process. To determine nutrient returns from field‐dried logging residue, four red maple (Acer rubrum L.) and chestnut oak (Quercus prinus L.) trees were felled and skidded into a 2‐ha clearcut area. Twig and leaf samples were collected immediately after cutting and after 2, 4, 8, and 16 weeks of field‐drying. Declines in both P and K concentrations in the leaves and twigs were noted over the drying period. When nutrient returns were computed on a kg ha−1 basis the following returns were observed after 16 weeks of drying: N, P, K, Ca, and Mg were 37, 2, 34, 20, and 2 kg ha−1, respectively. These amounts are similar to those cycled annually in litter‐fall in Appalachian mixed oak stands, which indicates that from a nutrient conservation standpoint, summer logging followed by field‐drying may be comparable to winter (leaf‐off) logging in these stands.
The Toxicity of Selected Organic Chemicals to the Earthworm Eisenia fetida
Authors: Neuhauser E. F. , Loehr R. C. , Malecki M. R. , Milligan D. L. , Durkin P. R. 
Published: July 2010

AbstractA number of methods recently have been developed to biologically evaluate the impact of man's activities on soil ecosystems. Two test methods, the 2‐d contact test and the 14‐d artificial soil test, were used to evaluate the impact of six major classes of organic chemicals on the earthworm Eisenia fetida (Savigny). Of the organic chemicals tested, phenols and amines were the most toxic to the worms, followed in descending order of toxicity by the substituted aromatics, halogenated aliphatics, polycyclic aromatic hydrocarbons, and phthalates. No relationship was found between earthworm toxicity as determined by the contact test and rat, Rattus norvegicus Berkenhout and mouse, Mus musculus L. LD50 values. The physicochemical parameters of water solubility, vapor pressure, and octanol/water partition coefficient for the chemicals tested in the contact test did not show a significant relationship to the E. fetida LC50 values. These studies indicate that: (i) earthworms can be a suitable biomonitoring tool to assist in measuring the impact of organic chemicals in wastes added to soils and (ii) contact and artificial soil tests can be useful in measuring biological impacts.
Grouting as a Remedial Technique for Buried Low‐Level Radioactive Wastes
Authors: Spalding B. P. , Hyder L. K. , Munro I. L. 
Published: July 2010

AbstractSeven grout formulations were tested in the laboratory for their ability to penetrate and to reduce the hydraulic conductivities of soils used as backfills for shallow land burial trenches. Soils from two sites, in Oak Ridge, TN, and Maxey Flats, KY, were used and both are classified as Typic Dystrochrepts. Three soluble grout formulations (sodium silicate, polypropenamide [polyacrylamide], and 1,3‐Benzenediol [resorcinol]‐formaldehyde) were able to both penetrate soil and sand columns and reduce hydraulic conductivities from initial values of ca. 10−4 m s−1 to < 10−8 m s−1. Three particulate grouts (lime [calcium oxide]‐fly ash, fly ash‐cement‐bentonite, and bentonite alone) could not penetrate columns; such formulations would, therefore, be difficult to inject into closed burial trenches. Field demonstrations with both sodium silicate and polyacrylamide showed that grout could be distributed throughout a burial trench and that waste‐backfill hydraulic conductivity could be reduced several orders of magnitude. Field grouting with polyacrylamide reduced the mean hydraulic conductivity of nine intratrench monitoring wells from 10−4 to 10−8 m s−1. Grouting of low‐level radioactive solid waste in situ, therefore, should be an effective technique to correct situations where leaching of buried wastes has or will result in groundwater contamination.
Estimating Algal Available Phosphorus in Suspended Sediments by Chemical Extraction
Authors: Dorich R. A. , Nelson D. W. , Sommers L. E. 
Published: July 2010

AbstractThe availability of sediment inorganic phosphorus (Pi) to algae was determined in 28 suspended stream sediments collected from an agricultural watershed in northeastern Indiana by short‐ (2‐d) and longerterm (14‐d) incubations. Unincubated sediment was also analyzed for dissolved molybdate reactive Pi (DMRP) and Pi extracted by: (i) sequential NaOH and HCl, (ii) sequential NH4F, NaOH, and HCl, (iii) nitrilotriacetic acid (NTA), (iv) hydroxy‐Al resin, and (v) total P. Available P (Paa) measured in sediments by 2‐d and 14‐d incubations with algae averaged 21 and 25% of total sediment P, respectively. Extraction of sediments with 0.1 M NaOH, 0.5 M NH4F, sequential 0.5 M NH4F + 0.1 M NaOH, NTA, and hydroxy‐Al resin removed an average of 36, 22, 31, 45, and 17% of the total P, respectively. Of the extractants tested, NaOH‐extractable Pi was significantly correlated with 2‐d and 14‐d Paa (r = 0.89*** and 0.95***, respectively) but NaOH extraction removed amounts of Pi that exceeded sediment Paa by a relatively constant amount. The results suggest that a single extraction with 0.1 M NaOH can be used to estimate both short‐ and longer‐term Paa in suspended stream sediments derived from noncalcareous soils in the Northcentral USA.
Formation of Secondary Minerals in Artificially Weathered Fly Ash
Authors: Warren C. J. , Dudas M. J. 
Published: July 2010

AbstractA leaching experiment was designed to evaluate the chemical, mineralogical, and morphological nature of precipitation products formed during the accelerated laboratory weathering of an alkaline fly ash. The ash, classified as alkaline Modic, was leached with 0.005 mol L−1 H2SO4 in a series of five leaching columns for a period of approximately 90 d. The weathered residues were characterized by x‐ray diffraction, differential thermal analysis, infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. Three types of precipitation products were identified in the ash. Calcite formed through the dissolution of Ca from the ash and subsequent reaction with CO2 absorbed by the initial alkaline leaching solutions. Iron, dissolved from the ash under acidic conditions, precipitated as amorphous coatings on fly ash particles. Aluminum and Si dissolved from the glass of the ash was translocated and precipitated within alkaline environments as an amorphous aluminosilicate material best described as proto‐imogolite. Results indicated that the products of weathering of fly ash in terrestrial environments are similar to those documented for alkali soils and some soils of volcanic origin.
Nutrient Removal Potential of Selected Aquatic Macrophytes
Authors: Reddy K. R. , De Busk W. F. 
Published: July 2010

AbstractThe role of eight aquatic macrophytes in removing N and P from nutrient enriched waters was evaluated using microcosm retention ponds. The aquatic macrophytes included water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), pennywort (Hydrocotyle umbellata), duckweeds (Lemna minor and Spirodela polyrhiza), azolla (Azolla caroliniana), salvinia (Salvinia rotundifolia), and a submersed macrophyte, egeria (Egeria densa). Nitrogen removal by aquatic macrophyte systems was in the order of water hyacinth > water lettuce > pennywort > Lemna > Salvinia > Spirodela > egeria during the summer season, while pennywort ranked first during the winter followed by water hyacinth, Lemna, water lettuce, Spirodela, Salvinia, and egeria. Phosphorus removal in summer was highest by water hyacinth and egeria systems, while pennywort and Lemna showed high P removal rates during the winter compared to other plants. Nitrogen and P removal were generally higher in summer than winter. Plant uptake accounted for 16 to 75% of total N removal, and 12 to 73% of total P removal, indicating the possibility of N and P removal by the mechanisms other than assimilation by plants.
Modeling Soil Response to Acidic Deposition in Nonsulfate Adsorbing Soils
Authors: Bloom P. R. , Grigal D. F. 
Published: July 2010

AbstractA simple semiempirical model for the prediction of changes in soil pH and base saturation with acidic deposition was developed. In steady‐state ecosystems acidic deposition results in losses of basic cations from exchange sites. In the model, depletion of exchangeable bases is calculated from the difference between input acidity and output of H+ and Al3+ in water percolating through the solum. A correction for the decrease in bicarbonate weathering is made but sulfate adsorption is not considered. Estimates including the effect of increased mineral weathering with decreased pH can be made if the natural weathering rate is known and if the order with respect to H+ is known for the rate expression for soil weathering. The model predicted laboratory data for the acidification of samples for three soil horizons. For a fourth horizon, that was formed in contact with bedrock and high in weatherable minerals, the model overestimated the effect of the acid. Model predictions using soil data showed a slow decrease in soil pH and base saturation until the pH region of Al buffering was attained and then a new steady‐state was achieved. The pH and base saturation in the Al buffering region was similar to that found in very acid soils under forest vegetation.