bluuebunny/crossref_metadata_2025_split huggingface dataset:
Model for Long‐term Phosphate Reaction Kinetics in Soil
Authors: van der Zee Sjoerd E. A. T. M. , van Riemsdijk Willem H. 
Published: July 2010

AbstractA simplified reaction kinetics model for long‐term P‐sorption in soils receiving large quantities of P‐rich animal manure is presented. Results from soil analyses for samples taken in 84 fields in nine different soil types indicate that the oxalate extractable P provides a good estimation of total P. Sorption experimental data for reaction periods up to 249 d show that measured sorption is proportional to In(t). Total sorption, F, (at long reaction periods) that includes P already present (Pox) appears to be proportional to the sum,M, of oxalate‐extractable Fe and Al. These results are described with a model where soil reactivity is related linearly to M, and the reaction kinetics are expressed in terms of a composite concentration time variable, I. This leads to the relationship F = kM In(I), where k is a characteristic of the soil. Comparisons with results in literature indicate that the concentration dependence of the reaction is accurately described by using I instead of time as a variable. Differences in reactivity (k) for different soil horizons or soil types are apparent from the different k values for topsoils and subsoils. Sorption measured during 40 h (Fr) may be extrapolated to long‐term (1–2 yr) sorption (Fm) for each soil separately without correction of the value of I for the reaction period in the field by simply setting Fm = Pox + 1.8 Fr. For a P concentration of 5 mmol L−1 this leads to a value of αm = Fm/M = 0.63 ± 0.14 for topsoils. Extrapolation using the average k value found for short‐term sorption experiments results in the same value of αm.
Metal Availability in Sludge‐amended Soils with Elevated Metal Levels
Authors: Rappaport B. D. , Martens D. C. , Reneau R. B. , Simpson T. W. 
Published: July 2010

AbstractField studies were conducted in 1984 with in situ controlled lateral flow plots to determine Cd, Cu, Ni, and Zn availabilities for corn (Zea mays L.) grown on sludge‐amended soils. These plots were constructed in Bojac loamy sand (Typic Hapludult), Davidson clay loam (Rhodic Paleudult), and Groseclose silt loam (Typic Hapludult) located in the Coastal Plain, Piedmont, and Ridge and Valley provinces of Virginia, respectively. An aerobically digested sludge from a wastewater treatment plant with major industrial inputs was applied to the soils at rates of 0, 42, 84, 126, 168, and 210 dry Mg ha−1. The highest sludge rate supplied 4.5 kg Cd, 760 kg Cu, 43 kg Ni, and 620 kg Zn ha−1. Corn grain and stover yields at the three locations increased linearly as a function of increased rate of sludge application (r2 ≥ 0.92**, significant at the 0.01 level). Metal concentrations in corn grain and earleaves from all treatments on the three soils were within normal levels. Nonsignificant relationships occurred between levels of DTPA‐extractable Cd, Cu, Ni, and Zn and the respective metal concentration in corn earleaves for data combined over the three soils. Amounts of DTPA‐extractable Cd, Cu, Ni, and Zn in the Ap horizon of the three soils increased linearly (r2 = 0.76** to 0.88**) with rate of sludge application. Maximum DTPA‐extractable metal levels in the soils were 0.6 mg Cd, 150 mg Cu, 4.0 mg Ni, and 75 mg Zn kg−1. The order of DTPA‐extractable metal concentrations in the soils, Cu > Zn > Ni > Cd, paralleled the amounts of metals applied via sludge application. Phytotoxicity did not occur in the corn grown on these diverse soils, even where Cu and Zn were applied in excess of USEPA guidelines.
Tall Fescue Production and Nutrient Status on Southwest Virginia Mine Soils
Authors: Roberts J. A. , Daniels W. L. , Bell J. C. , Martens D. C. 
Published: July 2010

AbstractTall rescue (Festuca arundinacea Schreb.) is a hardy grass species commonly used in surface mine reclamation and soil conservation. This study documented changes in fescue production (five growing seasons) and nutrient status (three growing seasons) as influenced by spoil type and various amendments. In Exp. I, fescue growth and nutrient status on five mixes of fertilized sandstone (SS) and siltstone (SiS) spoils were compared. A 2:1 SS/SiS control and treatments of 112 Mg ha−1 sawdust, native topsoil, and 22, 56, 112, and 224 Mg ha−1 municipal sewage sludge were compared in Exp. II. Standing biomass was measured in 1982–1984 and 1986 and tissue nutrient levels were measured in 1982–1984. High SiS spoils inhibited initial biomass production in Exp. I, but parent material effects diminished with time. All spoil mixes maintained adequate fescue production for five growing seasons, primarily due to small annual N additions (56 kg ha−1). In Exp. II, highest yields were maintained on ≥56 Mg ha−1 sludge treatments. Fescue production declined consistently through 1984 in all other treatments, probably due to N stress. Fescue production was highest the second year (1983) in all treatments of both experiments, but dropped sharply in 1984. Overall results indicate N was most limiting to production in the short term, but P becomes limiting over time. Sludge‐amended soils supported higher N, P, and cation tissue concentrations. Total P uptake appeared to be limited by low N levels, even when adequate soil P was available. potassium uptake rates greatly exceeded K fertilizer applications. Heavy metal uptake was not a problem, even in very high sludge treatments. Sludge‐amended mine soils were superior to both native topsoil and inorganically fertilized spoils in their ability to sustain long‐term fescue production without periodic augmentation.
The Influence of Selenium, Salinity, and Boron on Alfalfa Tissue Composition and Yield
Authors: Mikkelsen R. L. , Haghnia G. H. , Page A. L. , Bingham F. T. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) was grown in greenhouse sand culture to determine the effects of Se(VI), SO2−4‐salinity and B on alfalfa tissue composition and yield. A 4 × 2 × 2 factorial experiment was conducted with treatments consisting of four Se concentrations (0, 0.25, 0.5, and 1.0 mg Se(VI) L−1 as Na2SeO4), two B concentrations (0.5 and 3.0 mg B L−1 as H3BO3), and two salinity levels (0.5 and 5.0 dS m−1 as Na2SO4 and CaSO4·2H2O). Three cuttings were made and the vegetative portions analyzed for dry weight and total Se, S, and B. Plant yields were significantly reduced by both salinity and Se(VI) but not by B. Tissue Se concentrations were positively correlated with Se in the irrigation water but negatively correlated with SO2−4‐salinity and B. Plant Se was reduced from 620 mg Se kg−1 to less than 7 mg Se kg−1 in the presence of SO2−4‐salinity. A synergistic effect between Se and S was found at the basal nutrient concentration of SO2−4 (0.5 mM). Tissue S was increased from less than 3 g S kg−1 to over 10 g S kg−1 with the addition of 1 mg Se L−1. Alfalfa can potentially accumulate extremely high concentrations of Se when exposed to soluble Se(VI) in the root zone.
Oxygen Transport through Selected Aquatic Macrophytes
Authors: Moorhead K. K. , Reddy K. R. 
Published: July 2010

AbstractThe extent of O2 transport from aerial plant tissue into the root zone was evaluated for several floating and emergent aquatic macrophytes that have characteristics favorable for wastewater treatment. The highest O2 transport rates from aerial tissue into the root zone were associated with plants having a small root mass. As root mass increased, the rate of O2 transport decreased for aquatic macrophytes evaluated. Pennywort (Hydrocotyle umbellata L.) had the highest O2 transport rate of all aquatic macrophytes with an overall rate of 3.49 g O2 kg−1 dry root mass h−1. Pickerelweed (Pontederia cordata L.) had the highest O2 transport capacity of emergent plants with a rate of 1.54 g O2 kg−1 h−1. Waterhyacinth [Eichhornia crassipes (Mart.) Sollms], an important floating aquatic plant in wastewater treatment, had a transport rate of 1.24 g O2 kg−1 h−1. Nitrification in a waterhyacinth‐based water treatment system due to O2 transport was calculated to vary from 6 to 22 kg ha−1 d−1.
Nitrogen Dioxide Effects on Photosynthesis in Soybean
Authors: Sabaratnam Sashikala , Gupta Gian , Mulchi Charles 
Published: July 2010

AbstractVery little information is available on the effects of nitrogen dioxide (NO2) on photosynthesis in soybean [Glycine max (L.) Merr.]. This investigation was undertaken to study the effects of NO2 (0.0, 0.1, 0.2, 0.3, and 0.5 µL/L) on net photosynthetic rate (PN), stomatal resistance (SR), and dark respiration rate (DR) of soybean cultivar Williams treated 7 h/d, for 5 d in a controlled environment. Measurements of PN, SR, and DR were made both immediately and 24 h after the termination of exposure, using a LICOR 6000 Portable Photosynthesis system. Treatment effects on PN and DR were statistically significant. Increases of 18 and 23% in PN were observed immediately following exposure to 0.2 µL/L NO2 and after a 24‐h recovery period. With the 0.5 µL/L NO2 treatment reductions in the PN of 23 and 50% were observed immediately after exposure and following the 24‐h recovery period. Dark respiration rates of leaves treated with NO2, 0.2 µL/L, were 13 and 46% higher than the control immediately after the exposure and after the 24 h recovery. Exposure to 0.2 µL/L of NO2 had a stimulating effect whereas 0.5 µL/L of NO2 inhibited photosynthesis in soybean.
Effects of Forest Floor Leachate on Sulfate Retention in a Spodosol Soil
Authors: Gobran George R. , Nilsson S. Ingvar 
Published: July 2010

AbstractBecause of the involvement of several different mechanisms, sulfate retention in forest soils is a rather complicated process. We have investigated the effect of the dissolved substances from the forest floor of a Haplorthod soil (A0 horizon) on SO2−4 mobility in the upper mineral soil (A1/A2 horizon). Sulfate retention (SO2−4 retained in a solid phase) was estimated using two different solutions—distilled water solution (DWS) and forest floor leachate (FFL). Different concentrations of SO2−4 (0.00–2000 mg S L−1) were added to both extractants as Na2SO4‐35S. The results show that sulfate retention by the mineral soil (A1/A2) increased linearly with increasing SO2−4 concentration in the DWS containing up to 500 mg S L−1, whereas retention was zero when the soil was equilibrated with the FFL containing <250 mg S L−1. However, retention started to increase linearly when the FFL contained more than 250 mg S L−1. These data indicate that in the range of SO2−4 found under field conditions, SO2−4 retention was completely inhibited by the leachate solutions. These data also suggest that the organic ligands in the FFL were competing with SO2−4 on the exchangeable positive charge sites. Moreover, they may have an inhibitory effect on the growth of some SO4‐Al mineral compounds, mainly jurbanite and/or basaluminite.
Disposal of Septic Tank Effluent in Calcareous Sands
Authors: Whelan B. R. 
Published: July 2010

AbstractPerth, Western Australia, has 430 000 households with septic tanks discharging through sandy soils into the groundwater, which is pumped for domestic irrigation and public water supply. This study investigated the suitability of calcareous sands (Xeropsamment), one of Perth's major soil types, for treatment of septic tank effluent. Calcareous sands adjacent and below two septic tank systems were sampled to a depth of 8 m and the soil pH, soil N, and soil P contents were measured. The soil solution was sampled by an immiscible displacement technique and analyzed for N and P. Most of the NH4‐N in the effluent was oxidized to NO3‐N in the unsaturated zone just below the slime layer. Nitrate (NO−3) was present in the soil solution up to a concentration of 50 mg L−1 down to the maximum depth sampled of 8 m. The acidity produced during nitrification of the NH4 dissolved carbonates from the soil changing the soil pH. Below one system, the carbonates were completely removed from the first 4 m of soil lowering soil pH from 9.5 to 5.2. The NO3 in the soil solution was used to monitor the effluent flow pattern, which below one system had significant lateral flow indicating development of preferred flow paths. The soil P was increased by sorption and precipitation of P from the soil solution until it reached an equilibrium. At equilibrium the soil solution P was at the same concentration as in the effluent and the P sorbed on the soil was at a maximum for that concentration. Further down the profile where the sorbed soil P was not at its maximum, all the P was sorbed from the soil solution in a vertical distance of 0.5 m. The suitability of calcareous sands and limestone areas for acidic waste disposal may be limited by rapid dissolution of carbonate and the consequent release of previously sorbed P. Monitoring of effluent disposal in these calcareous soils is made more difficult by the development of preferred flow paths.
Microbial Biomass and Activity in a Subarctic Soil Ten Years After Crude Oil Spills
Authors: Sparrow Stephen D. , Sparrow Elena B. 
Published: July 2010

AbstractThis study documents the residual effects of summer and winter experimental oil spills on soil 10 yr after application. Measurements included adenosine triphosphate (ATP) levels, in vitro carbon dioxide evolution, cellulose and wood decomposition, soil N, and total and non‐oil C. About 18 and 14 kg petroleum residues per m2 remained in the soil in the winter and summer spills, respectively, and no reinvasion of plants had occurred in areas heavily impacted by the spills. Soil ATP levels averaged about 100 mg m−2 in the control soils and were about threefold higher than in the oiled soils, indicating reduced microbial biomass in the oily soils. There were no differences in in vitro CO2‐C evolution rates in the three soils, suggesting that there were similar levels of available substrate in both oiled and control soils. Cellulose and wood decomposition rates in the field were much lower in the oiled plots than in the unoiled soil. Nonpetroleum organic C levels averaged about 12 kg m−2 and were not significantly different between control and oiled soils, indicating that in the field little decomposition of organic matter had occurred in the oiled plots. Total N levels averaged about 5.5 kg m−2 in the oiled plots, which was significantly higher than the 4 kg N m−2 in the control plots. This was possibly due to N deposition of parts of plants killed by oil and to N2 fixation coupled with reduced N losses from the oiled soils. Ammonium‐N accumulated in the oiled soils at much higher levels than in the control soil. Results of this study showed that crude oil spills in subarctic forests can have long‐lasting effects on soil biological properties.
Growth and Uptake of Selenium by Swiss Chard in Acid and Neutral Soils
Authors: Zhang Penchu , Ganje T. J. , Page A. L. , Chang A. C. 
Published: July 2010

AbstractThe absorption of Se by plants in acid and neutral soils in relation to the concentration and chemical form of Se added was studied. Selenate‐Se added to an acid soil in amounts equal to or greater than 1.0 mg kg−1 significantly reduced yields of Swiss chard (Beta vulgaris L. var. cicla). Selenite‐Se, however, added to the acid soil at levels up to 2 mg kg−1 did not affect yields. Likewise, yields were also unaffected when selenite or selenate was added alone or in combination to a neutral soil at levels up to 2 mg Se kg−1. Amounts of Se absorbed by plants from soils where selenate was added were greater than where selenite was added. Selenate added to the soils was, in part, reduced to selenite during the growth period.
Atmospheric Sulfur Deposition to Agricultural Land in Northeastern Ohio
Authors: Morra M. J. , Dick W. A. 
Published: July 2010

AbstractIn certain forms, S is an important acid‐forming substance deposited from the atmosphere to the earth's surface. Controversy surrounds estimates of total S deposition because of an inability to accurately measure S in dry deposition (particulate fallout and gaseous sorption). In a field experiment in northeastern Ohio, the amount of S in dry deposition was determined over a 3‐yr period using 20 lysimeters (4.8 m by 1.7 m) cropped with soybean [Glycine max (L.) Merr.]. Two treatments consisting of tillage (conventional or no‐tillage) and elemental S addition (0 or 50 kg ha−1) were applied to the lysimeters. Sulfur inputs to the lysimeters as precipitation and agricultural amendments and S outputs, as runoff and leachate waters, were determined using ion chromatography or alkaline oxidation techniques. The net S output (total outputs minus measured inputs) was considered to equal dry deposition. Precipitation and agricultural amendment inputs of S were 10.2 and 3.8 kg ha−1 yr−1, respectively. In comparison, S in dry deposition ranged from 14 to 26 kg ha−1 yr−1 for the conventional tilled treatment and from 25 to 39 kg ha−1 yr−1 for the no‐tilled treatment, with the upper values of these ranges considered most accurate. Dry deposition is clearly as important as precipitation in contributing to the total S load at this location. A sulfur dry deposition estimate of only 15 kg ha−1 yr−1 was made based on average deposition velocity and ambient SO2 levels. Total deposition models, which rely on dry deposition estimates obtained by the use of SO2 concentrations and an average deposition velocity, may yield inaccurate values of total S additions to the earth's surface.
Effects of Simulated Acidic Precipitation on Plant‐Insect Interactions in Agricultural Systems: Corn and Black Cutworm Larvae
Authors: Stinner Deborah H. , Stinner Benjamin R. , McCartney David A. 
Published: July 2010

AbstractEffects of simulated acidic precipitation on food utilization, growth, development, and herbivory of black cutworms (Agrotis ipsilon) on corn (Zea mays L.) in the most economically important life‐history combinations of plant and insect were investigated in a series of laboratory and greenhouse experiments. A nutritional‐index technique was used in petri‐dish experiments with fourth, fifth, and sixth instar black cutworms to determine if acid precipitation could affect the amount of food consumed via affects on insect physiological parameters. Larvae were fed corn plants that were watered two times weekly with simulated precipitation (pH 2.8, 4.2, and 5.6) until the larvae pupated (total deposition of 8–10 cm of precipitation). The inverse relationship between the index of approximate digestibility (AD), which was higher in the pH 2.8 and 5.6 treatments, and the efficiency of conversion of digested food indices (ECD), which was lowest in the pH 2.8 treatment, suggested a stress effect of high acidity. A series of six greenhouse pot experiments was conducted to assess effects of acid precipitation on black cutworms and their interactions with growing corn plants. Fourth, fifth, and sixth instar larvae were placed in pots containing soil and corn plants, which were initially in the first or second leaf stage, and simulated acid precipitation (pH 2.8, 4.2, and 5.6) was applied two times per week until the larvae pupated (8–16 cm total deposition). Significant treatment effects were observed in the sixth instar larvae on two‐leaf corn experiment, where the larvae grew larger and developed faster in the pH 2.8 and 4.2 treatments than in the 5.6 treatment. Acid precipitation treatments did not significantly affect black cutworm damage to corn plants in any of these experiments.
Preferred Movement of Nonadsorbed Chemicals on Wet, Shallow, Sloping Soils
Authors: Steenhuis Tammo S. , Muck Richard E. 
Published: July 2010

AbstractPreferred movement of chloride and nitrate during runoff events following nutrient application was studied experimentally on 109 m long fields with a hard pan at shallow depth near Ithaca, NY. Chloride and nitrate applications were surface‐applied and incorporated at 36 and 69 m uphill from the collection point. All of the applied chemicals, when surface‐applied on saturated soil, were completely lost in the surface runoff and interflow water. When incorporated, at most 60% of the mass applied was lost. The fraction lost appeared to be related to the initial moisture content of the soil. After a chemical application, the concentration in both runoff and interflow was initially high and then decreased exponentially. The concentrations in the runoff water, interflow, and macropores were approximately equal throughout a runoff event.
Is Water a Relevant Sampling Medium for Toxic Chemicals? An Alternative Environmental Sensing Strategy
Authors: Ongley Edwin D. , Birkholz Detlef A. , Carey John H. , Samoiloff Martin R. 
Published: July 2010

AbstractUsing an uncomplicated 960 km reach of the North Saskatchewan River, we examine pathways and distribution of anthropogenic contaminants in water and in suspended and bottom sediments. Synoptic sampling during stable low flow allows maximum inference of point sources and, therefore, of chemical complexity. After chemical extraction of contaminants into two fractions for aqueous samples, and five fractions for sediment samples, we are able to assess the toxicity of the fractions using two independent bioassays—the Panagrellus redivivus nematode assay and a nonstandard modification of the Ames bacterial test. Our observations include (i) little comparability between toxic response of whole water samples and suspended sediments contained in the whole water samples; (ii) a much greater toxic response and larger number of priority chemicals associated with suspended sediments than in water samples; (iii) observed priority chemicals can exist in water or on sediments, yet produce no toxic response in one or both of the bioassay procedures; and (iv) significant toxicity is observed in the absence of priority chemicals. Results lead to questioning of efficacy of a standard menu of priority chemicals applied to water samples for ambient (i.e., not end‐of‐pipe) aquatic quality sensing (monitoring) purposes. We conclude that water may be an inappropriate medium upon which to base toxic chemical criteria for toxic chemical sensing purposes in aquatic systems. The menu approach to toxic chemical sensing is neither cost nor information efficient. We propose an alternative sensing protocol using a coupled chemical‐bioassay protocol that reduces the number of chemicals analyzed, produces an objective biological index of relative toxic response, provides a backup for presence of toxic chemicals not included in the chemical screen, and conveys meaningful ecological information upon which agencies can make program decisions.