bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance of Trees, Shrubs, and Forbs Seeded Directly in the Fall on Minespoil and Silt Loam Soil
Authors: Brown James E. , Maddox Joe B. , Splittstoesser Walter E.
Published: July 2010

This study was designed to find tree, shrub, and forb species that could be collected in the summer and early fall and be sown together sufficiently late in November to prevent fall germination, but early enough that some seeds could be properly stratified by winter conditions for germination the following spring. Germination and growth of tree, shrub, and forb species in association with grasses as ground cover were tested on a silt loam soil (pH 6.5) and a minespoil (mixed gray shale, pH 6.1) under microplot conditions. Seed germination was recorded 6 months after sowing, and trees and shrubs were then thinned to six per microplot to reduce plant competition. After two full growing seasons, plant heights and root depths were measured. Germination percentages of trees and shrubs were not significantly different between the minespoil and the silt loam soil. Generally, plant heights were shorter for plants grown on the minespoil, with a concomitant reduction in root depth. Trees and shrubs that performed well (a minimum of 15% germination, 10 cm plant height, and 20 cm root depth) on the minespoil under these conditions included Amorpha fruticosa (Indigo bush), Elaeagnus umbellata (Autumn olive), Malus sieboldi (Toringo crabapple), Prunus serotina (Black cherry), and Robinia pseucoacacia (Black locust). There was no significant difference in germination of forb seeds between the minespoli and the silt loam soil. Forbs that germinated, survived and grew well on the minespoil. Forbs with at least 10% germination and a 60% survival rate were Cassia fasciculata (partridge pea), Chenopodium album (lambsquarter), Desmodium canadense (beggerlice), Erechtites hieracifolia (fireweed), Eupatorium serotinum (snake root), Phytolacca americana (pokeweed), Polygonum pensylvanicum (smartweed), and Rumex crispus (red sorrel).
Fractionation and Characterization of Two Aerobic Sewage Sludges
Authors: Steinhilber Patricia , Boswell F. C.
Published: July 2010

Aerobic sewage sludges from Winder and Norcross, Ga. were subjected to chemical fractionation to study the distribution of sludgeborne Zn and infrared spectroscopic analysis to investigate watersoluble and insoluble light (<2 g/cm3) organic components. Sequential chemical fractionation indicated that the two sludges probably contained different kinds of Zn compounds. Ammonium acetate (NH4OAc) and EDTA (C10H16O8N2) extracted a greater percentage of the total Zn in Norcross sludge. Sodium hypochlorite (NaOCl) + ammonium acetate and acid ammonium oxalate [(NH4)2C2O4] (darkness) extracted a greater percentage of the total Zn in Winder sludge. A comparable percentage of the total Zn in both sludges was extracted by acid ammonium oxalate [UV (ultraviolet) light]. Infrared analysis indicated polysaccharidic and proteinaceous materials in the soluble and insoluble light organic sludge components, with indications of aromatic compounds in the insoluble light component. Incorporation of sludge into soil and exposure to the soil environment for 2 y (weathering or aging) caused considerable changes in the chemical extractability of the sludge Zn. The percentage of total Zn in the ammonium acetate extracts increased with weathering for both sludges. The proportion of total sludge‐borne Zn in the EDTA extract increased with weathering in the Winder sludge but was not significantly affected in the Norcross sludge. The percentages of the total Zn in the sodium hypochlorite and ammonium acetate and acid ammonium oxalate extracts remained relatively unchanged with weathering. Infrared analyses of the soluble organic component before and after weathering suggested a decrease in concentration of functional groups with weathering. The insoluble light organic component was apparently not affected by weathering.
Ammonium Adsorption by a Zeolite in a Static and a Dynamic System
Authors: Weber M. A. , Barbarick K. A. , Westfall D. G.
Published: July 2010

New types of soil amendments are being considered to reduce the leaching losses of N fertilizers. One such potential soil amendment is clinoptilolite, which is a natural zeolite with ion exchange properties and an affinity for the ammonium ion (NH4+). The objectives of this study were to quantify the adsorption of ammonium (NH4) by a clinoptilolite in a shaking study (static system) and to measure how effective this zeolite was in increasing NH4 retention in soil leaching columns (dynamic system). A batch equilibrium shaking test showed that this zeolite adsorbed 4.3 times more NH4 than the Nunn clay loam (Aridic Argiustoll) soil. When mixed together with the soil and placed in 6.35 cm (i.d.) by 30 cm long columns (dynamic system), the zeolite significantly reduced the leaching of NH4+ only at a relatively high application rate (135 Mg ha−1). comparison of the two zeolite application methods at the highest zeolite rate (135 Mg ha−1) showed that banded treatments significantly reduced the leaching of NH4+, compared with treatments where zeolite was homogenously mixed with the entire soil volume. Indications are, however, that large quantities of clinoptilolite would be required to reduce NH4+ leaching in fine‐textured soils.
Increased Success of the Mexican Bean Beetle on Field‐Grown Soybeans Exposed to Sulfur Dioxide
Authors: Hughes P. R. , Dickie A. I. , Penton M. A.
Published: July 2010

Field‐planted ‘Hodgson’ soybeans [Glycine max (L.) Merr.] were enclosed in screened cages and fumigated intermittently with SO2 by means of a tube fumigation system. The concentration of SO2 averaged 367 µg m−3 for 191 h over a 68‐d period, giving a seasonal average of 42 µg m−3. One week after fumigation began, six pairs of newly emerged Mexican bean beetle adults (Epilachna varivestis) were introduced into each of the cages. In less than one generation time, the mean number of progeny from these beetles feeding on fumigated plants was 1.5 times greater than that of the beetles feeding on control plants. Larval growth was also significantly greater on the fumigated plants, especially for females. These crop × insect interactions which occur at low intermittent doses of SO2 increase the potential impact of the insects on crop production.
Factors Affecting Ammonia Volatilization from Sewage Sludge Applied to Soil in a Laboratory Study
Authors: Donovan W. C. , Logan T. J.
Published: July 2010

A forced‐air polyvinyl chloride (PVC) cylinder manifold chamber was used to collect ammonia (NH3) volatilized from sewage sludges applied to soil in the laboratory. A series of experiments were conducted in which the effect on NH3 volatilization of a single variable was studied. The reference control conditions were: Columbus, Ohio anaerobically digested liquid sewage sludge applied at 5 Mg ha−1 (dry wt) to a Crosby silt loam soil (pH 6.7) at 0.01 MPa initial moisture tension. The soil was bare and the sludge was unincorporated during the 24‐h study period. Air temperature was 26 ± 2°C. The variable conditions were: (i) initial soil moisture (0, 0.01, 1.5 MPa and air‐dry); (ii) time of incorporation (0.25, 1, 3, 6, 12, and 24 h after sludge application); (iii) soil pH (5.1, 6.7, 7.5); (iv) sludge type (anaerobically digested Columbus liquid sludge, partially dewatered Columbus anaerobic sludge, aerobically digested Medina liquid sludge, lime stabilized primary Ashland sludge, and composted primary Columbus sludge); (v) temperature (12.8, 18.3, 26.7°C); and (vi) vegetative cover [bare, grass sod (Poa pratensis), wheat straw (Triticum aestivum)].

Initial soil moisture contents ≤1.5 MPa tension increased NH3 volatilization compared with air‐dry soil. Volatilization increased linearly with time elapsed before sludge incorporation. Ammonia loss was greater from soil at pH 7.5 than at pH 6.7 or 5.1. There was significantly greater loss of NH3 from the lime‐stabilized sludge (pH 12) than from the anaerobic and aerobic sludges. No detectable NH3 was lost from the compost. Volatilization decreased with decreasing temperature. When the sludge contained large sludge particles, NH3 loss increased with vegetative cover. However, cover had no effect when the sludge was well homogenized. For all experiments, 24‐h volatilization losses ranged from 0 to 32% of the NH3‐N applied.
A Simple and Efficient Sediment Corer for Shallow Lakes
Authors: Ali Arshad
Published: July 2010

A sediment‐coring device for shallow lakes (< 1–4 m deep) is described. This device yields undisturbed sediment cores and quantitative samples of phytoplankton at the sediment‐water interface.

The device is mechanically reliable and performed infallibly in a variety of soft and hard substrates encountered in central Florida lakes. It is lightweight (7 kg), not cumbersome, and can be easily fabricated from commonly available materials costing < 40 U.S. dollars as of June 1983. This corer is a simple alternative to the great diversity of core samplers in use today, most of them fairly expensive to manufacture.

This sampling tool is versatile in that it can be used by aquatic biologists and chemists interested in spatial and stratigraphic studies, pesticide residue chemists, sediment microbiologists, and sediment ecologists interested in studying the redox phenomenon.
Atrazine and Simazine Movement to Wye River Estuary
Authors: Glotfelty D. E. , Taylor A. W. , Isensee A. R. , Jersey J. , Glenn S.
Published: July 2010

The Wye River, a tributary of Chesapeake Bay, is a shallow, well‐mixed estuary surrounded by an agricultural watershed, a large portion of which is planted in corn (Zea mays L.). A 3‐y study of the movement of atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine) and simazine (2‐chloro‐4,6‐bis(ethylamino)‐s‐triazine) showed that the total amount of herbicide reaching the estuary depended upon the quantity applied in the watershed and the timing of runoff with respect to application dates. In a year in which significant runoff occurred within 2 weeks of application, 2 to 3% of the atrazine moved to the estuary. In other years with less runoff, or runoff delayed longer after application, much smaller quantities reached the estuary. Simazine loading was one‐tenth that of atrazine. Once in the estuary, atrazine and simazine remained in solution, diluted in a conservative manner with estuarine water, and dissipated with a 10‐ to 30‐d half‐life. The maximum measured concentration of atrazine was near 15 µg L−1 but average concentration at peak loading was < 3 µg L−1. Thus, although the Wye River has a high percentage of watershed land planted to corn, herbicide concentrations rarely approached those producing minor effects on submerged aquatic vegetation.
Pasture Runoff Water Quality from Application of Inorganic and Organic Nitrogen Sources
Authors: Mc Leod R. V. , Hegg R. O.
Published: July 2010

Surface runoff water quality from a rescue pasture receiving surface application of organic wastes and commercial fertilizer was evaluated at Clemson University (Clemson, S.C.). Dairy manure, poultry manure, and municipal sludge were the organic wastes used in this experiment. Ammonium nitrate was the commercial fertilizer. The organic wastes and commercial fertilizer were applied at the rate of 112 kg N ha−1 to eight plots during four different periods. Due to an extremely dry year, runoff events were produced by irrigation. The runoff water was collected and samples were analyzed for pH, total P, total suspended solids, total Kjeldahl N, NH4‐N, NO3‐N, and chemical oxygen demand.

The nutrient concentrations in surface runoff were more dependent on the number of rainfalls since application of the fertilizer than on the quantity of rainfall or runoff. The concentrations of potential pollutants from surface‐applied organic wastes or commercial fertilizer were reduced by between 80 and 55% after two runoff events. The NO3‐N concentration in the surface runoff from the plots receiving the commercial fertilizer exceeded the permissible public water supply standard during the first runoff event. The overall nutrient loss in the runoff was found to be minimal (< 4% of total Kjeldahl N and chemical oxygen demand and < 2.5% of total P).
Bryozoans—Possible Indicators of Environmental Quality in Bear Creek, Mississippi
Authors: Cooper Charles M. , Burris John W.
Published: July 2010

Collections of samples of water and substrate materials from lakes and stream sections of Bear Creek, Miss., were studied to determine the species of Bryozoa present in different habitats of an aquatic ecosystem with an intensively cultivated flatland watershed (440 km2). Bear Creek (83 km long), a tributary of the Yazoo River in the Mississippi River alluvial delta, is actually a series of six riverine lakes connected by a sluggishly flowing stream. The watershed also includes several other oxbow lakes connected to the stream only during periods of high discharge. Water quality as characterized by total and suspended sediments, deposited sediments, pH, and coliforms deteriorated in a downstream direction. Four species of the sessile colonial invertebrate were indigenous to the three lakes in the system having the lowest total solids, sedimentation rates, and pH. These included Plumatella fruticosa (Allman), Lophopus crystallinus (Pallas), Fredericella sultana (Blumenbach), and Pectinatella magnifica (Leidy). Absence of bryozoans, especially environmentally sensitive Pectinatella magnifica, in downstream areas correlated with degradation of downstream habitat and increased total solids. Selective habitation of these invertebrates in the Bear Creek stream system indicates the possible use of these organisms as environmental indicators of habitat quality.
Gaseous Nitrogen Losses from Soils Under Zero‐Till as Compared with Conventional‐Till Management Systems
Authors: Aulakh M. S. , Rennie D. A. , Paul E. A.
Published: July 2010

The gaseous losses of N from conventional‐till (CT) and zero‐till (ZT) crop fields were 3 to 7 and 12 to 16 kg N ha−1 y−1, respectively. In contrast, losses from CT and ZT fallow were severalfold higher, namely, 12 to 14 and 34 kg N ha−1, respectively. The more dense surface soil and consistently higher moisture content (lower air‐filled porosity) were identified as major factors affecting increased denitrification under ZT. The potential denitrification rates were markedly higher under ZT, and the population of denitrifiers was up to six times higher than in CT soil samples.

The contribution of lower soil horizons towards gaseous N losses was found to be low on both CT and ZT fields, and this finding was confirmed from a survey carried out on three other widely differing soils.

Volumetric soil moisture and air temperature were the only two of several factors that accounted for a significant portion of the variations in gaseous N fluxes under field conditions.

The average mole fraction of N2O ranged from almost 100% to as low as 28% of the total gaseous products and showed a negative relationship with soil moisture.
Yield and Elemental Concentration of Sweet Corn Grown on Tannery Waste‐Amended Soil
Authors: Stomberg A. L. , Hemphill D. D. , Volk V. V.
Published: July 2010

Tannery waste was applied to Willamette silt loam soil (fine‐silty, mixed, mesic, Pachic Ultic Argixeroll) to determine possible elemental toxicities and N availability to ‘Jubilee’ sweet corn (Zea mays L.). Sweet corn yields; Cr, Cu, Mn, Zn, and N concentrations in soil and in leaves and kernels of sweet corn; and the organic matter content, electrical conductivity, and pH of soils were measured. Sweet corn yields increased with waste application in 1978 but not in 1979. Leaf N, Mn, and Zn and kernel Mn concentrations increased with waste application in both years. Leaf and kernel Cu and Cr concentrations did not increase significantly with waste application and no metal toxicity symptoms were observed in either year.

Total Cr and extractable Cu, Mn, and Zn concentrations of soils increased with waste application. Extractable Cu, Mn, and Zn concentrations declined 1 y after application, suggesting reduced metal availability with time. Metals applied with the waste did not move through the soil profile. Soil pH, electrical conductivity, organic matter content, total Kjeldahl N (TKN), and NH4‐ and NO3‐N concentration increased with waste application. A significant increase in soil NO3‐N concentration at the 90‐cm depth followed waste application. Tannery waste could provide significant N and lime for crops, but application at high rates may be limited by salt content, heavy metal accumulation, or potential movement of NO3‐N into groundwater.
Sulfate Production Rates in Pyritic Pennsylvanian‐Aged Shales
Authors: Ainsworth Calvin C. , Blanchar R. W.
Published: July 2010

An incubation study was initiated to measure sulfate production within various shale layers of coal overburden. Samples of air‐dried, crushed, and sieved shale were adjusted to −33 kPa moisture potential and incubated with and without inoculation by a Thiobacillus thiooxidans, ferrooxidans, and thioparus culture at 298 K in either air or CO2‐enriched air. Samples were removed periodically during a 28‐d incubation and analyzed for SO42‐. Ninety percent of the variation in rate of pyrite oxidation was due to differences in the shale layers and there were no significant differences measured due to addition of bacteria or increased CO2 level. A zero‐order rate of SO42‐ production with respect to SO42‐ level was observed in all layers. The rate constants varied from 12 to 182 mg S/kg shale per day for the various shale layers. The rate of pyrite oxidation was higher in samples with pH values near 4 than those with pH values near 6.5.
Phosphorus Sorption of Soils to be used in Wastewater Renovation
Authors: Stuanes Arne O.
Published: July 2010

The same amount of P in 0.01M CaCl2 was repeatedly added to 12 soils to measure the P sorption of the soils. Compared with the P sorption maximum calculated from the Langmuir equation, repeated additions showed about twice as much sorption. However, the two measurements were well correlated. At low P concentration or in soils with low sorption capacity, each addition showed about the same sorption increment after the first three to four additions. Between 6 and 35% of the amount sorbed after 10 additions of P was desorbed in 10 subsequent additions of 0.01M CaCl2. The P sorption was lower at 4°C than at room temperature. The only soil parameter that significantly influenced the sorption capacity with dithionite—citrate extractable Al. The sorption capacity measured by repeated additions of a solution of the same P concentration as wastewater seems to give a better estimate of the field sorption capacity than the Langmuir sorption maximum.
Phytotoxicity in Bush Bean of Five Sulfur‐Containing Gases Released from Advanced Fossil Energy Technologies
Authors: Taylor G. E. , Selvidge W. J.
Published: July 2010

Sulfur‐containing gases including sulfur dioxide (SO2), hydrogen sulfide (H2S), carbon disulfide (CS2), carbonyl sulfide (COS), and methyl mercaptan (CH3SH) are a major class of atmospheric emissions from advanced fossil energy technologies. Although phytotoxicity data for SO2 and H2S exist, the influence on vegetation of the remaining S gases is not known. This study was designed to address the comparative toxicity of the five gases in bush bean (Phaseolus vulgaris). Seedlings were exposed to each gas individually for 6 hr at a range of concentrations (6–82 µmol m−3) in an open gaseous exchange system, during which whole‐plant net photosynthesis and transpiration were monitored. At the highest exposure levels, leaf necrosis was assessed 3 d after exposure. Transpiration did not respond consistently to any of the treatments. Neither CS2 nor CH3SH caused any change in photosynthesis or foliar necrosis. Based on the inhibition of photosynthesis and the development of leaf necrosis at equivalent volumetric concentrations in the atmosphere, the toxicity of the remaining three gases was SO2 > H2S > COS. The relationship between net photosynthesis and exposure dosage (concentration × time) for H2S, SO2, and COS was curvilinear and biphasic, exhibiting in each gas an enhancement of photosynthesis followed by inhibition as the dosage increased. For projected emission rates from advanced fossil energy facilities, the results suggest that releases of CH3SH and CS2 are not likely to influence vegetation. Since plant response to H2S, SO2, and COS is strongly dosage dependent, accurate estimates of field effects due to these three gases must await more adequate air quality modeling near commercial‐scale facilities.
Effects of Aeration and Temperature on Nutrient Regeneration from Selected Aquatic Macrophytes
Authors: Ogwada R. A. , Reddy K. R. , Graetz D. A.
Published: July 2010

A batch incubation study was conducted to investigate the effect of aeration and temperature on the N and P release by decomposing aquatic macrophytes in eutrophic lake water. Nutrient release by waterhyacinth (Eichhornia crassipes [Mart] Solms), pennywort (Hydrocotyle umbellata L.), hydrilla (Hydrilla verticillata L.), and cattails (Typha latifolia L.) was evaluated under aerobic conditions. Waterhyacinth plants tagged with 15N were used to determine the 15N release at varying temperature levels and under anaerobic (oxygen free) and low‐dissolved O2 (open system where the only O2 source was diffusion through the overlying water) conditions.

Nutrient release was found to be rapid initially due to solubilization, followed by slow nutrient release as a result of microbial decomposition. Under aerobic conditions, NO3− formation in the water was found to be significantly related to C/N ratio of the plants. About 48 to 76% of the plant N and 67 to 90% of the plant P were released at the end of 105 d of aerobic decomposition. After 94 d, about 86 and 88% of 15N was released from the plant tissue under anaerobic and low‐dissolved O2 conditions, respectively. Nitrogen and phosphorus release were significantly increased with increase in incubation temperature.
Contamination of the O2 Soil Horizon by Zinc Smelting and its Effect on Woodlouse Survival
Authors: Beyer W. N. , Miller G. W. , Cromartie E. J.
Published: July 2010

Samples of litter from the O2 horizon of Dekalb soil (loamy‐skeletal, mixed, mesic Typic Dystrochrept) were collected from 18 ridgetop sites on a transect that ran by two Zn smelters in Palmerton, Pa. Metal concentrations increased by regular gradations from a minimum at a site 105 km west of the smelters (67 mg/kg Zn, 0.85 mg/kg Cd, 150 mg/kg Pb, 11 mg/kg Cu) to a maximum 1.2 km east of the smelters (35 000 mg/kg Zn, 1300 mg/kg Cd, 3200 mg/kg Pb, 280 mg/kg Cu), and then decreased until they reached an eastern minimum at the easternmost site, 19 km from the smelters. An increase in the P concentrations near the smelters showed that the emissions were disrupting nutrient flow through the ecosystem. An increase in the pH near the smelters was attributed to the high concentrations of Zn. The log of the distance of the sites from the smelters was significantly correlated (r = −0.80, p < 0.05) with the mortality of woodlice (Porcellio scaber Latreille) fed samples of the litter during an 8‐week test. There was substantial mortality of woodlice observed even in the O2 litter collected 19 km east of the smelters. Zinc, cadmium, lead, copper, and sulfur were experimentally added, alone or in combination, to O2 litter collected far from any known source of metal emissions. The highest concentration of Zn added (20 000 mg/kg) was toxic enough to account for the mortality observed in the earlier test. A lower concentration of Zn (5000 mg/kg) as well as the concentration of Cd (500 mg/kg) tested also significantly (p < 0.05) increased the mortality of woodlice.
An Approach to Predicting the Movement of Selected Polluting Metals in Soils
Authors: Amoozegar‐Fard A. , Fuller W. H. , Warrick A. W.
Published: July 2010

An approach is developed to derive simple, field‐oriented equations to predict movement of pollutant metals in soils. The procedure is illustrated by a comprehensive example utilizing experimental work on small columns with Cd, Ni, and Zn on nine soils and eight landfill‐type leachates. The results provide a set of simple equations to predict movement of the three metals through soils with minimal calculations. The final form enables the scientist or field engineer to calculate velocities for which a given concentration of the metal is propagated through the soil profile. The simplified forms are based on the Lapidus‐Amundson (L.A.) model, for which apparent diffusion and forward and backward reaction coefficients are best fitted to whatever experimental data are available. The L.A. model is then used to generate the propagation velocities for constant concentration, which are related back to the soil and leachate properties by multiple regression. The regression equation is what the field person uses and the choice of coefficients is based on available input data. The specific coefficients developed for this data‐set may be used directly if no other experimental data are available for a given site.
Nitrate Leaching as Influenced by Water Application Level and Nitrification Inhibitors
Authors: Timmons D. R.
Published: July 2010

The effects of water application level and nitrification inhibitors on NO3−‐N leaching from a sandy loam soil were evaluated using soil columns and nonweighing field lysimeters. In soil columns (297 mm diam by 1.2 m deep) fertilized with 224 kg N ha−1, addition of the nitrification inhibitor nitrapyrin [2‐chloro‐6‐(trichloromethyl)pyridine] reduced NO3−‐N leaching losses by 51 and 30 kg ha−1, respectively, for the 12.7‐ and 38.1‐mm weekly water application levels. Both nitrapyrin and Terrazole (5‐Ethoxy‐3‐trichloromethyl‐1,2,4‐thiadiazole) (Olin Corp., Little Rock, Ark.) inhibitors were equally effective in reducing total NO3−‐N leaching losses from soil columns after 100 d for the 38.1‐mm water application level. The change in flow‐weighted NO3−‐N concentration due to use of nitrification inhibitors was about −0.4 to −1.0 mmol L−1.

Annual NO3−‐N leaching losses measured at the 1.2‐m depth in field lysimeters cropped with corn (Zea mays L.) over a 3‐yr period averaged about 12 kg ha−1 less (7%) for nitrapyrin‐coated urea. The results were not consistent since nitrapyrin reduced NO3−‐N leaching during the growing season by 12 and 17% for 2 of the 3 yr and post season leaching by 35% for 1 yr. The change in flow‐weighted NO3−‐N concentration (3‐yr avg) due to nitrapyrin was −0.4, −1.5, and +0.9 mmol L−1, respectively, for the growing season, post season, and preemergence periods. Nitrification inhibitors may help to minimize nonpoint‐source pollution on sandy soil where supplemental irrigation is used by reducing and/or delaying NO3−‐N leaching particularly during the growing season when N is utilized by plants.
Plant Availability of Heavy Metals in a Sludge‐Treated Soil: II. Metal Extractability Compared with Plant Metal Uptake
Authors: Singh B. R. , Narwal R. P.
Published: July 2010

A greenhouse study was conducted to investigate the uptake of Cd, Ni, Pb, Co, and Zn by fodder rape (Brassica napus L. ‘Kenton’) and extractability of these metals from sewage sludge‐treated soils at different levels of sludge application and soil pH. Metals extracted by several extractants were correlated to their uptake by rape. Total uptake of Cd, Ni, Pb, and Zn increased and that of Co decreased as the rate of sludge application increased. Uptake of all metals except Pb generally decreased as soil pH increased.

The extractability of most metals was in the order: HNO3 > aqua regia > HCl > NH4OAc (pH 4.8) > DTPA > H2O. It was governed by rates of sludge application but was little affected by change in soil pH. The percentage of exchangeable form of all metals was < 1% and 90 to 99% of the total metals in sludge‐treated soils was bound in organic and sulfide forms.

Cadmium extracted by HCl, NH4OAc (pH 4.8), and diethylenetriaminepentaacetic acid (DTPA) as well as that determined after digestion of soil with HNO3 and aqua regia showed significant correlation with its uptake by rape. The same was true for Pb except for HNO3, where correlation coefficient was not significant. For Co, Ni, and Zn, none of the extractants used gave an adequate prediction of their plant availability, as most of the correlation coefficient values obtained were low. Of the extractants used in this study, though none gave a reliable prediction of plant availability of all the metals, DTPA yielded significant r values for Cd and Pb. Thus, DTPA may be considered better than other extractants for predicting the availability of Cd, Pb, and possibly Zn in fodder rape under varying levels of sludge application and soil pH.
Nitrogen Balance in a Citrus Orchard
Authors: Dasberg S. , Erner Y. , Bielorai H.
Published: July 2010

Differential fertilizer and irrigation applications were utilized to assess the N balance over a period of 4 yr in a typical mature ‘Shamouti’ orange (Citrus sinensis L.) grove located in the coastal plain of Israel. Nitrogen inputs in fertilizer and irrigation water were 100, 180, and 310 kg ha−1 annually for the three main treatments. The N removed by the crop was measured by yield and N content determinations in the fruits; the leached N was measured by sampling below the root zone. It was found that the amount of leached N was similar in the low and medium N applications (< 50 kg N ha−1). At the high N application, > 50 kg N ha−1 was leached and large amounts of N were unaccounted for (approximately 100 kg N ha−1). Analysis of published data on N losses from citrus orchards showed similar large amounts of N not found in the fruit or in the soil mineral N pool after large N applications. The possible pathways for these N losses were discussed. It was concluded that this excess N was either incorporated in the soil organic matter or stored in the tree rather than being denitrified.
Fate and Effectiveness of Tebuthiuron Applied to a Rangeland Watershed
Authors: Emmerich W. E. , Helmer J. D. , Renard K. G. , Lane L. J.
Published: July 2010

Tebuthiuron3 (N‐[5‐(1,1‐Dimethylethyl)‐1,3,4‐triadiazol‐2‐yl]‐N.N′‐dimethylurea), a herbicide, was applied at a rate of 0.84 kg/ha to a rangeland watershed and test plots in pelleted and dissolved forms, respectively. The removal of tebuthinron in the runoff water from the watershed was determined for each runoff event. After 21 months, total tebuthiuron removed in runoff water was 0.47% of that applied. The low removal rate was credited to the timing of the tebuthiuron application. Tebuthiuron applied to test plots moved to a depth of 15 cm in 8 months with 326 mm of precipitation. Total tebuthiuron remaining in the test plots after 21 months was 38% of the amount applied. The time required for the concentration of tebuthiuron in the test plots to reach non‐detectable levels was estimated to be from 2.9 to 7.2 years. Tebuthiuron was effective on the dominant species on the watershed 21 months after treatment, producing an apparent 100% kill for tarbush (Flourensia cernua DC.), fourwing saltbush [Atriplex canescens (Pursh) Nutt.], and littleleaf sumac (Rhus microphylla Engelm. ex Gray), and 61, 92, and 0% for creosote‐bush [Larrea tridentata (DC.) Cov.], whitethorn (Acacia constricta Benth.) and graythorn (Condalia spathulata Gray), respectively.
Effects of Acidic and Neutral Sulfate Salt Solutions on Forest Floor Arthropods
Authors: Craft C. B. , Webb J. W.
Published: July 2010

Acidic and neutral SO42− solutions were applied to a mixed oak (Quercus spp.) forest floor on Walker Branch Watershed in eastern Tennessee to study effects of increased acid deposition on decomposer arthropods and arthropod regulation of P cycling. Treatments consisted of ambient (no applications), 2 × (low), and 10 × (high) annual atmospheric inputs of SO42− (as K2SO4) and H+ plus SO42− (as KHSO4). Arthropods were sampled monthly in litter and mineral soil. Soils were analyzed for Bray no. 2 P and for salt pH, NH4Cl exchangeable Al3+ and K+, and water‐extractable SO42−.

Over a 14‐month period, the number of forest floor macroarthropods averaged 19% lower in the high SO42− salt treatment compared with the control. Macroarthropod fungivores also were adversely affected by the high SO42− salt treatment and by the high and the low KHSO4 treatments. The effects of the high SO42− treatment on macroarthropods may have resulted from a salt effect caused by the concentrated K2SO4 applications (112 mmol K+ m−2 per application). Microarthropod numbers increased significantly in response to the low K2SO4 additions and to the high and low KHSO4 treatments. Microarthropod fungivores, predators, and detritivores responded similarly. Comparison of microarthropod densities and soil K+ concentrations suggested that the response resulted from a direct fertilizer effect of K+ on arthropods or indirectly from an effect on microorganisms.

Mineral soil pH, exchangeable Al3+, and Bray P were unaffected by the treatments. Soil pH (0–15 cm) was unaffected by the KHSO4 applications because most of the H+ addition was neutralized by the forest floor. Analysis of litter leachate during a single treatment interval (5 weeks) indicated that only 31% of the H+ applied in the high KHSO4 treatment reached the mineral soil.

Although increased inputs of H+ appear to have little effect on decomposer arthropods, effects of nonacidic SO42− warrant further study.
Effect of Loading Rate and Soil Amendments on Inorganic Nitrogen and Phosphorus Leached from a Wastewater Soil Absorption System
Authors: Uebler R. L.
Published: July 2010

Permissable wastewater loading rates for ground absorption sewage disposal systems in North Carolina are currently estimated from an on‐site characterization of soil texture and structure; but, after the trenches of the system are dug, the actual ability of the soil to absorb the applied wastewater may be far less than the estimated loading rate due to smearing of the trench‐soil interface. This study was designed to evaluate the effects of wastewater loading rate and soil amendments proposed to help overcome the detrimental effect of soil smearing on wastewater treatment by a soil absorption system.

Three loading rates, 7.5, 11.3, and 15.0 L m−2 d−1, were tested and two soil amendments, cement and lime, were compared with a control. The amendments were added to the soil on a 5% by‐weight basis. Three absorption trenches, 3.0 m in length, were dug for each loading rate‐soil amendment combination. Soil water samples were obtained monthly for 12 months from ceramic cups placed 15 and 30 cm below the trenches. Water samples were analyzed for NH4+‐N, NO3+‐N, soluble P, chloride and pH.

Concentrations of NH4+‐N, NO3−‐N, and soluble P varied significantly with the time of sampling. Transformation of NH4+‐N to NO3−‐N was enhanced by the soil amendments, indicating that the aeration status of the soil near the trenches was improved by the amendments. The effect of the amendments was most noticeable during the spring recovery period as aeration status was increasing from winter minimums. Higher NO3−‐N levels for the cement as compared with the lime in spring suggest that cement may be a more effective amendment than lime. The lowest loading rate had significantly higher concentrations of NO3−‐N during the spring months. Soluble P levels increased linearly from 0.1 to 0.9 mg L−1 over the first year operation of the system.
Adsorption of Phosphate, Arsenate, Methanearsonate, and Cacodylate by Lake and Stream Sediments: Comparisons with Soils
Authors: Wauchope R. D. , Mc Dowell L. L.
Published: July 2010

The adsorption of phosphate, arsenate, MSMA (sodium methanearsonate) and cacodylic acid (hydroxydimethylarsine oxide) by 14 sediments from streams and lakes of the Mississippi River alluvial flood plain was measured using a phosphate fixation test and also dilate (1 g/100 mL) sediment‐water slurries at 50 and 500 µg/L P or As. The fixation experiment results were similar to a previous study with soils from the same geographic area in that sorption of the four species were similar and correlated with clay and extractable Fe and Al content. In contrast with the soils results, phosphate was more strongly adsorbed than the arsenicals because the sediments were richer in Fe and Al oxides than soils of the same clay content and the phosphate sorption index was most dependent on sediment Fe and Al content. Conversely, the arsenicals were most correlated with clay or Fe content. Arsenical fixation also exhibited some sediment‐pH dependence indicative of binding with Ca. In the dilute slurry experiments, the high‐clay sediments were extremely adsorptive of all the species and yielded equilibrium P concentration (EPC) values from 0.07 to 0.3 µg/L P. Cacodylate adsorption was dependent on sediment pH. Those sediments with high clay content had a very large unfilled capacity to adsorb phosphate or arsenate, and would act as sinks for P or As inputs into their associated lakes or streams.
Nitrous Oxide Emissions from Agricultural Soils in Wisconsin
Authors: Goodroad L. L. , Keeney D. R. , Peterson L. A.
Published: July 2010

Nitrous oxide (N2O) emissions from field plots on a Plano silt loam soil (Typic Argiudolls) at the University of Wisconsin‐Arlington Experimental Farm were measured from the summer of 1979 through autumn 1981. The treatments, selected to give a wide variation in management, were: reduced tillage (till‐plant) corn (Zea mays L.); rye (Secale sativa L.) cover; long‐term stable pH (pH 4.7, 5.1, and 6.7); oat (Avena sativa L.) straw residue; alfalfa (Medicago sativa L.) residue; and dairy manure and sewage sludge amendments. Nitrous oxide fluxes, measured by a static chamber technique, were greatest with the manure‐amended and reduced tillage treatments, and were greater in 1980 than in 1979 or 1981. Highest rates of N2O emission were often observed at soil thaw. No significant effects on the emission rate or amount of N2O evolved due to soil pH was observed. Surface N2O fluxes were characterized by a high degree of variation. Mean N2O‐N emission rates calculated from measured N2O‐N emission rates during annual sampling periods ranged from 1.6 to 38.7 ng N2O‐N m−2 s−1 for the treatments sampled. Coefficients of variation for these means ranged from 50% to > 200% and from 100 to 350% for spatial and temporal variability, respectively. Total N2O emissions (kg N2O‐N ha−1) for 1980, the most complete sampling period, were: reduced tillage corn, 3.5 in the row and 6.3 between the row; sludge, 1.6; manure, 6.1; alfalfa, 3.2; rye, 1.6; straw, 2.2; pH 4.7, 1.5; pH 5.1, 0.9; pH 6.7, 1.0. These values are similar to those reported in the literature from comparable agricultural sites.
Predicted Erosion and Sediment Delivery of Fallout Plutonium
Authors: Foster G. R. , Hakonson T. E.
Published: July 2010

Plutonium (Pu) from fallout after atmospheric explosion of nuclear weapons in the 1950s and 1960s is being redistributed over the landscape by soil erosion and carried on sediment by streams to oceans. Erosion rates computed with the Universal Soil Loss Equation for about 200 000 sample points on nonfederal land across the USA were used to estimate Pu removal rates by soil erosion by water, Pu delivery in several major rivers, and concentration of Pu on the transported sediment. Estimates of average annual Pu delivery on sediment ranged from 0.002% of the initial fallout Pu inventory for the Savannah River basin to 0.08% for the Mississippi River basin. If the deposition of Pu had been uniformly 37 Bq/m2, the estimated Pu activity on suspended sediment ranged from about 0.26 Bq/kg of sediment for the Savannah River basin to 0.52 Bq/kg for the Columbia and Rio Grande river basins. After 1000 yr, about 9 to 48% of the initial Pu inventory will remain in U.S. soils that are eroding. Much of the Pu on eroded sediment will travel only a short distance from its origin before its host sediment particles are deposited and permanently located, at least for a few hundred years. As much as 90% of the initially deposited Pu will remain, redistributed over the landscape by erosion and deposition. Although the delivery rate of Pu by rivers will not decrease greatly in the next 100 yr, a significant decrease will likely occur by 1000 yr.
Estimating Labile and Dissolved Inorganic Phosphate Concentrations in Surface Runoff
Authors: Wendt R. C. , Alberts E. E.
Published: July 2010

Mathematical models are needed to better estimate effects of alternative management methods on the amounts of bioavailable P lost in surface runoff over a variety of soil, topographic, and climatic conditions. In this study, methods for estimating concentrations of soil‐derived labile (dissolved plus adsorbed) and dissolved P in runoff are proposed and tested. The methods are based on the assumption that most labile P contributed by soil to runoff is derived from soil particles that are detached and transported with runoff water. Effects of erosive selectivity are accounted for by dividing soil and sediment into five undispersed size fractions. Isotherms relating adsorbed labile and dissolved P levels were developed for each from soil analyses. Labile P concentrations in runoff were estimated by summing the product of labile P concentrations prior to entrainment in runoff and measured sediment concentrations for each of the size fractions. Dissolved P concentrations were estimated by distributing labile P between dissolved and adsorbed forms using a mass balance approach. Methods of estimation were tested with runoff from 14 natural rainstorms occurring on 10 fallow plots having soil P levels ranging from about 1.3 to 3.2 mmol kg−1 as labile P. Linear regressions of observed on estimated values of both labile and dissolved P were significant. For most events, slopes and intercepts of regression lines were not significantly different from one and zero, respectively, indicating good absolute agreement. Results indicate that soil analyses in combination with models for predicting the amount and size distribution of eroded soil form a basis for estimating movement of bioavailable P forms in runoff. However, additional studies are needed to determine the range of soil types for which the assumptions inherent in the development of the approach are valid.
Effect of Soil Processes on the Acidification of Water by Acid Deposition
Authors: Reuss J. O. , Johnson D. W.
Published: July 2010

The mechanism whereby acid deposition can cause acidification of surface waters via equilibrium processes in soil solution was investigated using chemical equilibrium models. These models show that for soils with low to moderately low exchangeable bases (15% Ca2+ saturation), the soil solution pH is only slightly affected by CO2 partial pressures over the range likely to be found in soils (1–5% CO2), but the alkalinity (defined as alkalinity = 2[CO32−] + [HCO3−] + [OH−] − [H+] − [Al3+] − [Al(OH)2+] − [Al(OH)22+] of the soil solution increases rapidly with increasing CO2 partial pressure (the brackets denote molar concentrations). In contrast, solutions that are not in contact with the soil's cation exchange complex maintain alkalinity independently of CO2 partial pressure. If alkalinity is positive, the pH in such solutions rapidly increases in response to decreasing CO2 pressure. Waters having positive alkalinity will undergo a rapid rise in pH when released from the soil due to CO2 degassing, while waters with negative alkalinity (net acidity) remain acid when degassed.

The effect on the soil of precipitation containing H2SO4 is to increase the SO42− concentration. In acid soils, ion exchange reactions that take place in response to increasing SO42− from 25 to 250 µmol (e−) L−1 can be expected to depress soil solution pH by 0.2 to 0.4 units. This depression is sufficient to cause a switch from positive to negative alkalinity in many soil solutions and when waters with negative alkalinity are released from the soil they remain acid when degassed. This mechanism could easily account for a change in pH of surface waters from 6.25 to 5.0 or less, while the associated change in soil solution would be < 0.3 units. This mechanism does not depend on soil acidification in the sense of a reduction in base saturation. It is completely reversible and responses to changes in SO42− concentration is instantaneous, so that lags in response to changes in sulfate input levels would be controlled only by processes such as soil sulfate adsorption and biological cycling that tend to buffer changes in SO42− concentration.
Saline Cooling Tower Water for Irrigation in Minnesota: I. Crop and Soil Effects
Authors: Engel R. E. , Malzer G. L. , Bergsrud F. G.
Published: July 2010

Saline cooling tower water (CTW) from the Northern States Power coal‐fired plant in Sherburne County, MN was used to irrigate a Hubbard loamy sand (Udorthentic Haploboroll). The objectives of this study were to determine the changes in soil solution salinity, to measure salt accumulations in the soil profile (0‐ to 240‐cm), and to assess the impact of CTW on crop production.

In a 3‐yr field study, CTW (2.2 dS m−1) was applied at two rates to alfalfa (Medicago sativa L.), corn (Zea mays L.), and fallow areas. Analysis of the soil water for electrical conductivity (ECsw) at 75 cm indicated that an increase in salt concentration occurred over the growing season. Maximum seasonal ECsw at 75 cm in the cropped areas (3.0–4.0 dS m−1) were higher than in the fallow areas (2.0–2.5 dS m−1). Rainfall between the growing seasons, however, was adequate to leach the upper 75 cm of this coarse‐textured soil and prevent a stepwise buildup of salts from one year to the next. After an initial buildup, ECsw at 225 cm was relatively stable. For the last 2 yr, ECsw at 225 cm was consistently higher under alfalfa than corn or fallow areas.

A seasonal buildup of SO4 occurred during the growing season. In the fall, SO4 accumulations in the 0‐ to 60‐cm soil layer were highest under corn. By the following spring, there was no difference between the three cropping systems. Rainfall was very effective in leaching seasonal accumulations of SO4 from the soil. A lower Ca/Mg ratio in the CTW, as compared with the soil, resulted in increased concentration of Mg in the 0‐ to 60‐ and 60‐ to 150‐cm soil layers.

Corn grain and alfalfa production averaged 8440 and 8230 kg ha−1 for the last two seasons, respectively, and were not adversely affected by salinity produced from the CTW application.