bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organic Carbon Fractions in Extracts of O and B Horizons from a New England Spodosol: Effects of Acid Treatment
Authors: David Mark B. , Vance George F. , Rissing Joseph M. , Stevenson Frank J. 
Published: July 2010

AbstractWe examined the effects of H2SO4 and HNO3 on dissolved organic carbon (DOC), pH, and DOC fractions in extracts from Spodosol O and B horizon samples of a forest soil from eastern Maine. Preliminary work with HNO3 at p[H+] = 3 (1 to 24 h shaking, ionic strength adjustment with NaNO3 (I = 0.1 to 0.001) indicated rapid equilibration (1 h) of DOC in treatment solutions with B horizon samples, but that DOC levels in extracts from the O horizon increased continuously over time. In the remaining work, H2SO4 and HNO3 and their Na salts were added at a constant I of 0.01 and solutions were recovered after shaking for 16 h. The DOC in O horizon extracts decreased with increasing acidity, reaching a minimum at p[H+] = 2 (from ca. 5 mmol C L−1 with no acid addition to ca. 2 mmol C L−1). For the B horizon extracts, DOC increased with increasing acidity. Percent neutralization of added H+ ranged from 18 to 99% in the O horizon for acid treatments ranging from p[H+] = 1 to 4 respectively; B horizon values were 16 to 85% for H2SO4 and 2 to 70% for HNO3. The DOC in O horizon solutions was dominated by hydrophobic and hydrophilic acids (ca. 45 and 20% of DOC, respectively), which were altered by acidic inputs; primarily by a decrease in hydrophobic acids (45 to ca. 15–18% of DOC) and an increase in hydrophilic acids (ca. 20 to 35–40% of DOC) as acidity increased. For the B horizon, similar trends were observed, although hydrophobic/hydrophilic acid ratios were lower, indicating that hydrophobic acids have a lower solubility with increasing acidity. From an environmental perspective, increasing acidic inputs through wet and dry deposition on forest Spodosols of New England may have significant consequences in the solubilization and transport of metals and acidity because of differences in DOC fractions.
Direct Effects of Simulated Acid Rain on Sexual Reproduction in Corn
Authors: DuBay Denis T. 
Published: July 2010

AbstractThe process of sexual reproduction in flowering plants often exposes pollen grains to the environment and the potential effects of atmospheric deposition. Experiments were designed to determine whether simulated acid rain treatments just before or after pollination could adversely influence reproductive processes and seed set in corn (Zea mays L.). Container‐grown corn with sexually mature tassels and ears were exposed once to simulated rain at four pH levels for 1 h, beginning 1 h after artificial pollination or ending 10 min before artificial pollination. The single, artificial pollination deposited an average of 85 pollen grains per silk. Simulated rain treatment at pH 4.5, 3.5, or 2.5 after pollination reduced the percentage seed set of treated ears 7, 29, and 34%, respectively, as compared with pH 5.5. Simulated rain at pH 5.5 after pollination reduced seed set 24% as compared with no‐rain controls. The pH of simulated rain applied before pollination did not affect seed set, and pH 5.5 rain applied before pollination had no effects on seed set compared to no‐rain controls. Microscopic observations indicated that pollen germination and pollen tube penetration of the silk were completed by the time the rain treatments began 1 h after pollination. This infers that simulated acid rain influenced pollen tubes after they entered the silks. These results suggest that plant sexual reproduction could be adversely affected by acidic precipitation at pH levels observed for rain events in eastern North America.
Temporal Variation in Nitrate and Nutrient Cations in Drainage Waters from a Deciduous Forest
Authors: Foster N. W. , Nicolson J. A. , Hazlett P. W. 
Published: July 2010

AbstractTemporal variations in soil solution and stream chemistry were examined in 1984 in an undisturbed sugar maple‐yellow birch (Acer saccharum Marsh.‐Betula alleghaniensis Britton) forest in the Turkey Lakes Watershed, Ontario. Nitrate was the dominant anion associated with cation depletion from soil. Nitrogen in precipitation was less important than soil N in the determination of solution chemistry. Growing‐season increases in NH+4 and NO−3 in soil solution were greatest in the Oe horizon and decreased with depth. Nitrate concentrations in mineral soil solution and streamwater were highest during the dormant period and peaked at the start of spring snowmelt. Although NO−3 concentrations in streamwater were positively correlated (r = 0.7–0.9) with NO−3 and Ca2+ concentrations in mineral soil solution during the dormant period, NO−3 contributed far less to cation fluxes in streamwater than HCO−3 or SO2−4.
Guidelines for Selenium in Irrigation Waters
Authors: Albasel N. , Pratt P. F. , Westcot D. W. 
Published: July 2010

AbstractBecause of the relatively high concentration of Se in the agricultural drainage waters of the west side of the San Joaquin Valley (SJV) in California and the potential for reuse of these waters on salt tolerant crops, a reassessment of quality criteria for Se in irrigation waters for this area was needed. The specific conditions for this area that justified a reassessment were (i) the Se in the drainage waters of the West Side is largely in the selenate (SeO4) form which is not appreciably adsorbed by soils and is thus readily leached from the root zone, (ii) the waters containing high concentrations of Se have substantial concentrations of sulfate (SO4) that dramatically reduce SeO4 adsorption by plants, (iii) the salinity of the waters that contain high Se concentrations demand leaching fractions (LF) that insure that Se is also leached from the root zone, and (iv) kinetics of Se‐species transformations. Recent research with alfalfa (Medicago sativa L.), which is one of the most sensitive as crop growth for Se accumulation, suggests that this crop can tolerate an average soil solution Se concentration (Sess) of 250 µg/L without exceeding the limit of 4 mg Se/kg in the dry weight of forage that has been set to protect bovine animals from Se toxicity. Based on a model the Se in the irrigation water (Seiw) can increase of 100 µg/L at LFs of 0.2 to 0.3 without exceeding the maximum (Sessm) established for this crop when irrigated with sulfate waters. Thus, the recommended maximum Seiw for alfalfa grown on the West Side of the SJV is 100 µg/L. Guidelines for other crops can be established if the relationships among Seiw, Sessm, LF, the Se in harvested products (Sehp), and the maximum Sehp for various uses of products for protection of wildlife, domestic animals, and humans are known.
Guidelines for Molybdenum in Irrigation Waters
Authors: Albasel N. , Pratt P. F. 
Published: July 2010

AbstractMolybdenum (Mo) in relatively high concentrations has been found in saline SO2−4‐dominated agricultural drainage waters of the West Side of the San Joaquin Valley (WSSJV) of California. Because of the potential for using these waters for irrigating salt‐tolerant crops, an assessment of quality guidelines for Mo for the specific conditions of the WSSJV was justified. The unique conditions of (i) alkaline soils favoring Mo mobility, (ii) the high leaching fractions required to control salinity in the root zone, and (iii) the effect of SO2−4 in reducing Mo absorption by plants suggested that the guideline of 10 µg L−1 to protect crops and animals be increased to 50 µg L−1 for the WSSJV. The Mo input at this concentration assuming the use of 10 000 m3 of water ha−1 will be 0.5 kg h −1.
Agricultural Impacts of Coal Mine Subsidence: Effects on Corn Yields
Authors: Darmody R. G. , Jansen I. J. , Carmer S.G. , Steiner J.S. 
Published: July 2010

AbstractUndergronnd coal mining methodology is moving toward techniques that cause immediate planned subsidence of the overlying land. Damage done by subsidence to structures has been documented, but the effects on agricultural productivity are undocumented. This study was conducted to (i) determine the extent of measurable subsidence effects associated with planned subsidence mining, (ii) measure the impact of subsidence on corn (Zea mays L.) yield, and (iii) compare the effects of longwall and high extraction retreat mining methods. Five locations in southern Illinois were included in the 3 yr of the study. A total of 4605 ha in 1985, 6747 ha in 1986, and 7764 ha in 1987 were involved. These areas represented unmined control areas as well as longwall (LW) and high extraction retreat (HER) types of mines. Aerial photographs of the study locations were taken in the spring of each year. Subsided areas were identified, classified, and measured on the photos. The average percent of the study urea with measurable subsidence effects was 7.5% for LW mining and 3.3% for HER mining. Corn was harvested each year on selected subsided and nearby unsubsided reference areas. The weighted average reduction in corn yield on land above the mines was calculated by multiplying the affected area by the associated yield reduction. The weighted average yield reduction was 4.7% for LW mining and 1.8% for HER mining. Results for the individual years varied with the weather: the greater the precipitation, the greater the yield reductions. The results also reflect the yearly variation in mining activity, crop sample areas, and overall study areas. In addition, the mitigation of subsidence effects in place at the time of the study also influenced the results, but the potential for mitigation for either mining type was not included in the research.
Vegetation of Waste Disposal Areas at a Coal‐Fired Power Plant in Kansas
Authors: Mulhern D. W. , Robel R. J. , Furness J. C. , Hensley D. L. 
Published: July 2010

AbstractDisposal of scrubber sludge and fly ash waste from coal‐fired power plants is a costly problem for utilities. Current regulations call for the retired waste areas to be covered with topsoil, then seeded to produce a protective vegetative cap. We conducted field tests over a 3‐yr period to determine if a vegetative cover could be established without first adding topsoil to waste sites. Seven herbaceous and six tree species were planted on scrubber sludge and bottom ash sites. These substrates were first amended with fertilizer, and then hay, woodchips, or cow (Bos taurus) manure. The bottom ash was not capable of supporting vegetative growth, even with amendment. Tall wheatgrass [Agropyron elongatum, (Host) Beauv.], tall fescue (Festuca arundinacea Schreb.], yellow sweet clover (Melilotus officinalis Lam.), and Japanese millet [Echinochloa crusgalli (L.) Beanv.] grew well on scrubber sludge, as did eastern cottonwood (Populus deltoides Marsh.) and eastern red cedar trees (Juniperus virginiana L.). Generally, herbaceous plants grew best on scrubber sludge to which manure and fertilizer were added, and the trees survived and grew best on scrubber sludge amended with woodchips and fertilizer. This study demonstrates that a good vegetative cover can be produced on scrubber sludge waste areas without first covering them with topsoil.
Effects of Long‐Term 2,4‐D and MCPA Field Applications on Soil Residues and Their Rates of Breakdown
Authors: Smith A. E. , Aubin A. J. , Biederbeck V. O. 
Published: July 2010

AbstractA 3‐yr rotation of wheat (Triticum aestivum L.), wheat, and summerfallow in field plots on a clay soil at the Indian Head Experimental Farm, Saskatchewan, has been receiving annual applications of ester and amine formulations of 2,4‐D (2,4‐dichlorophenoxyacetic acid) since 1947, and MCPA (4‐chloro‐2‐methylphenoxyacetic acid) since 1953. In the fall of 1987, after 40 successive applications of 2,4‐D and 34 annual treatments of MCPA, soil samples were taken from the 0‐ to 15‐cm and 15‐ to 30‐cm depths of replicate treatments. Gas chromatographic analysis revealed that residual amounts of 2,4‐D and MCPA were less than 0.02 mg kg−1, indicating that there had been complete degradation of the herbicides. Under laboratory conditions, the breakdown of 2.0 mg kg−1 (14C)2,4‐D and (14C)MCPA was slightly faster in soils that had received continuous applications with the appropriate herbicide, than in soil from the untreated control plots, suggesting some soil microbial adaptation in response to long‐term use of these herbicides.
Prediction of Soluble Phosphorus Transport in Agricultural Runoff
Authors: Sharpley A. N. , Smith S. J. 
Published: July 2010

AbstractThe soluble phosphorus (SP) concentrations of runoff for individual events from agricultural land were predicted using relationships describing soil P desorption kinetics and effective depth of surface soil‐runoff interaction (E). These values were compared with concentrations measured for runoff from 9 grassed and 11 cropped watersheds in the Southern Plains, USA, over a 10‐yr period. Using a constant value of E for a given watershed, measured SP concentrations were over‐estimated by up to 4415% for runoff events of > 0.75 mm in volume. Using a value of E calculated for each runoff event from soil loss, correlation coefficients between measured and predicted values and prediction errors were improved (R2 = 0.95–0.99 and error = 11–18%) compared to use of a constant E value (R2 = 0.21–0.83 error = 38–380%) averaged for each watershed location. Although these improvements did not significantly (5% level) affect estimates of the amounts of SP transported, the improvements will be important from environmental aspects, in terms of assessing the impact of agricultural management practices on P‐related eutrophication for all runoff events.
Heavy Metal Accumulation in Small Mammals following Sewage Sludge Application to Forests
Authors: Hegstrom Linda J. , West Stephen D. 
Published: July 2010

AbstractThe application of sewage sludge to forested land as a fertilizer may result in the transfer of heavy metals from sludge to wildlife. Levels of four heavy metals (Cd, Pb, Zn, and Cu) were measured in livers and kidneys of insectivorous Trowbridge's shrews (Sorex trowbridgii) and shrew‐moles (Neurotrichus gibbsii), and granivorous deer mice (Peromyscus maniculatus) from sludge‐treated and untreated sites at Charles Lathrop Pack Forest, located near Eatonville, WA. Heavy metal levels were higher in the organs of Trowbridge's shrews from sledge‐treated areas than in those from untreated areas. Only Cd was elevated in both organs of the deer mouse. Shrew‐moles from sludge‐treated sites had higher levels of Cd and Pb, but not Zn or Cu, than those from untreated sites. In general, heavy metal levels in the three species from control sites at Pack Forest were similar to levels found in animals from five other control sites in western Washington. Samples of liver and kidney tissue from Trowbridge's shrews were examined for evidence of heavy metal‐induced lesions. Despite the high levels of heavy metals found in Trowbridge's shrews, no lesions were found in their organs.
Effectiveness of Mechanical Aeration in Floating Aquatic Macrophyte‐Based Wastewater Treatment Systems
Authors: DeBusk T. A. , Reddy K. R. , Clough K. S. 
Published: July 2010

AbstractOutdoor tanks containing the floating aquatic macrophyte water hyacinth [Eichhornia crassipes (Mart) Solms] were provided with diffuse aeration to evaluate its effect on wastewater treatment efficiency and plant growth. Light aeration (0.003 and 0.021 L m−2 min−1) had no effect on the treatment of primary domestic effluent in the batch‐fed water hyacinth tanks. Heavy aeration (1.03 and 3.53 L m−2 min−1) raised wastewater dissolved oxygen (DO) concentrations, but did not improve biochemical oxygen demand (BOD5) removal efficiency or increase plant growth rates during 21‐d experiments. Heavy aeration slightly increased wastewater N removal, but the effectiveness of aeration for nutrient removal was not consistent among experiments. In continuous‐flow raceways fed primary domestic effluent, vigorous aeration (6.1 L m−2 min−1) improved effluent quality, with contaminant removal rates averaging 77% (BOD5) and 76% (suspended solids [SS]) in nonaerated raceways, and 94% (BOD5) and 89% (SS) in aerated raceways. Results of this study suggest that the high aeration requirement for enhanced contaminant removal in floating aquatic macrophyte systems (FAMS) is due not only to poor O2 transfer efficiencies (1.6–4.0%), but also to the inefficient utilization of O2 for BOD5 removal. The primary benefit of moderate aeration (0.1–1.0 L m−2 min−1) in FAMS appears to be the elevation of wastewater DO concentrations (from 0.5 to 2.5 mg L−1), which may be useful for controlling odors and mosquito proliferation.
Sulfate Adsorption and Desorption Reversibility in a Variety of Forest Soils
Authors: Harrison Robert B. , Johnson Dale W. , Todd Don E. 
Published: July 2010

AbstractSubsurface soil samples were collected from 20 forest sites of differing soil and cover type, atmospheric deposition history and physiographic location. Samples were analyzed for S pools, sulfate adsorption capacity, adsorption reversibility, and associated soil properties in order to compare the relative S chemistry and SO4 retention capacities of the sites. The SO4 adsorption capacity was determined by sequential equilibration of air‐dried soil samples with a percolating solution of 0.25 mM CaSO4, and adsorption reversibility by leaching both SO4 saturated and untreated soil samples with deionzed water. Phosphate extractable SO4 was measured at the end of each series of equilibrations as a means of estimating irreversibly adsorbed SO4. A total of 32 out of 36 soil horizons studied showed net SO4 adsorption, ranging from a desorption of 0.4 to an adsorption of 7.2 mmol SO4 kg−1. Thus, most of these soils were not yet saturated with respect to a solution concentration of 0.25 mM SO4. Most soil horizons showed irreversible SO4 adsorption (an average of 36% of adsorbed SO4 was retained irreversibly) as evidenced both by changes in phosphate extractable SO4 and by a comparison of desorption of SO4 before and after saturation by the 0.25 mM SO4 solution. When adsorption and adsorption reversibility observations were compared with measured soil properties, the presence of hydrous oxides of Al and native SO4 were the best indicators of SO4 adsorption potential. Most adsorption/desorption/extraction sequences showed mass conservation of SO4, indicating inorganic SO4 adsorption appeared to be far more important in these procdures than organic S incorporation or mineralization. It is unclear how much air‐drying, sample treatment, and the procedures followed might have changed the inorganic and organic S pools of these soils.
Analysis of Effects of Atmospheric Carbon Dioxide and Ozone on Cotton Yield Trends
Authors: Reddy V. R. , Baker D. N. , McKinion J. M. 
Published: July 2010

AbstractCotton (Gossypium hirsutum L.) yields have declined since 1964 despite improvements in technology and introductions of higher‐yielding cultivars. Cotton scientists have been unable to identify exact causes of the yield decline. For the past 25 yr, global atmospheric CO2 concentration ([CO2]) has been increasing due to the increased burning of fossil fuels; cotton has been found to be sensitive to [CO2]. Cotton has also been found to be sensitive to atmospheric ozone concentration ([O3]) at levels that occur regularly where it is grown.To analyze the effects of [CO2] and [O3] on cotton‐yield trends, simulations were made using the cotton crop model GOSSYM. Input data for simulations were obtained from cotton breeders' trial sites located at Florence, SC; Stoneville, MS; College Station, TX; Phoenix, AZ; and Fresno, CA.The simulated effects of the [CO2] and [O3] on cotton yields changed from location to location due to interactions with soil, plant, and atmospheric variables and with nutrient levels in the soil. Given enough N, the increased [CO2] would probably result in a 10% increase in lint yield. Due to N stress sometime during the growing season, however, the plants could not fully utilize the increased [CO2]. Ozone concentration increased during the period of cotton‐yield decline, and this increase in [O3] was found to affect simulated cotton yields adversely. It appears that O3 is one of the contributing factors to the yield decline. Overall O3 had a more adverse effect on simulated cotton yields at locations where O3 was present at higher concentrations, i.e., Phoenix, AZ and Fresno, CA.
Infiltration of Wastewater in a Newly Started Pilot Sand‐Filter System: III. Transformation of Nitrogen
Authors: Pell Mikael , Nyberg Fred 
Published: July 2010

AbstractThe objective of the study was to monitor the chemical dynamics associated with N transformations from start‐up until a steady state was reached in a pilot sand‐filter system consisting of a three‐chambered septic tank, a sand filter with a one person capacity, and eight columns. The system was loaded with 67 L m−2 d−1 of an artificial wastewater. The untreated wastewater contained 114 mg Kjeldahl N L−1 and 0.12 mg NH+4‐N L−1. Mineralization reached a steady state in the septic tank after 2 wk of operation; thereafter, 65 ± 6% of the effluent N was NH+4‐N. In the column effluent the concentrations of NH+4‐N increased during the first 6 wk of operation, whereafter a stabilization at 60 to 80 mg NH+4‐N L−1 occurred. The mean proportion of effluent N in mineralized form for the whole period was 88 ± 6%. Three weeks after start‐up, all effluent N from the sand filter was in mineralized form and remained high for the rest of the study period. The effluent concentrations of NH+4‐N increased rapidly during the first 2 wk after which it decreased to less than 3 mg L−1. The concentration of NO−3‐N was initially low. It then increased until about Day 30 when it stabilized at 64 to 71 mg NO−3‐N L−1. Elevated concentrations of NO−2‐N were observed between Days 8 and 45. Nitrifying activity reached a steady state after 6 wk of operation. During this state a considerable amount of nitrification took place in the upper 1.5 cm and all wastewater N had been nitrified after 15 cm of percolation. By the end of the operating period the total amount of influent N in the septic tank had been reduced by 17%. Corresponding reductions for the columns and sand filter were 18 and 33%, respectively.
Field Persistence Studies with the Herbicide Glufosinate‐Ammonium in Saskatchewan Soils
Authors: Smith Allan E. , Belyk Murray B. 
Published: July 2010

AbstractField plots on clay at Regina and Indian Head, and on clay loam at White City, Sask., were treated with glufosinate‐ammonium (the ammonium salt of DL‐homoalanin‐4‐ylmethylphosphinic acid) at a rate of about 1kg ha−1 during June or July 1988. At regular intervals, soil samples were taken from the 0‐ to 10‐cm and 10‐ to 20‐cm soil levels and extracted and analyzed gas chromatographically for glufosinate remaining. In addition, amounts of the soil metabolite MPPA [3‐(hydroxymethylphosphinyl)propionic acid] were also monitored. Providing there was adequate moisture, breakdown of the herbicide was rapid with no glufosinate detectable in any of the soils by the end of September 1988. In all soils the breakdown of MPPA was slower than that of glufosinate. Maximum amounts of the metabolite formed in the soils ranged from 0.26 kg ha−1 in the clay loam to 0.52 kg ha−1 in the clay at Regina. By the end of September there were 0.23, 0.06, and 0.17 kg ha−1 of MPPA in the 0‐ to 10‐cm soil level at Regina, White City, and Indian Head, respectively. There was no leaching of either glufosinate or MPPA to soil depths below 10 cm.