bluuebunny/crossref_metadata_2025 huggingface dataset:
Herbicide Banding and Tillage System Interactions on Runoff Losses of Alachlor and Cyanazine
Authors: Hansen N. C. , Moncrief J. F. , Gupta S. C. , Capel P. D. , Olness A. E.
Published: June 2010

Herbicides transported to surface waters by agricultural runoff are partitioned between solution and solid phases. Conservation tillage that reduces upland erosion will also reduce transport of herbicides associated with the solid phase. However, transport of many herbicides occurs predominantly in solution. Conservation tillage practices may or may not reduce transport of solution‐phase herbicides, as this depends on the runoff volume. Reducing herbicide application rate is another approach to minimize off‐site transport. Herbicide banding can reduce herbicide application rates and costs by one‐half or more. Our objective was to compare herbicide losses in runoff from different tillage practices and with band‐ or broadcast‐applied herbicides. The herbicides alachlor [2‐chloro‐2′,6′‐diethyl‐N‐(methoxymethyl)acetanilide] and cyanazine [2‐[[4‐chloro‐6‐(ethylamino)‐1,3,5‐triazin‐2‐yl]amino]2‐methylpropionitrile] were broadcast‐ or band‐applied to plots managed in a moldboard plow, chisel plow, or ridge till system. Herbicide concentration in runoff was largest for the first runoff event occurring after application and then decreased in subsequent events proportional to the cumulative rain since the herbicide application. When herbicides were broadcast‐applied, losses of alachlor and cyanazine in runoff followed the order: moldboard plow > chisel plow > ridge till. Conservation tillage systems reduced runoff loss of herbicides by reducing runoff volume and not the herbicide concentration in runoff. Herbicide banding reduced the concentration and loss of herbicides in runoff compared with the broadcast application. Herbicide losses in the water phase averaged 88 and 97% of the total loss for alachlor and cyanazine, respectively. Cyanazine was more persistent than alachlor in the soil.
Effects of Spent Mushroom Substrate Weathering on the Chemistry of Underlying Soils
Authors: Guo Mingxin , Chorover Jon , Fox Richard H.
Published: June 2010

Passive weathering of heaped material in the field is a popular method for treating spent mushroom substrate (SMS) before its reuse. During the weathering process, leachate containing high concentrations of dissolved organic matter and inorganic salts is released into the underlying soils, but effects on soil and ground water quality remain uncertain. We conducted a field study to measure the effects of SMS weathering on chemical and morphological properties of underlying soils. Two SMS piles, 20 m long, 6 m wide, and either 90 or 150 cm high, were placed in a fallow agricultural field dominated by grasses and weathered for 24 mo. Soil samples were taken from each genetic horizon under the SMS piles following their removal and analyzed for pH, total organic carbon (TOC), electrical conductivity (EC), water‐soluble organic carbon (WSOC), water‐soluble inorganic cations and anions, and exchangeable inorganic cations. Compared with an unaffected control, SMS weathering did not raise soil TOC, but did alter soil pH, and significantly increased EC, WSOC, and water‐soluble and exchangeable inorganic ions. At 200 cm below the soil surface, the EC, WSOC, and water‐soluble Cl−, NO−3, Ca2+, Mg2+, Na+, and K+ under SMS piles were 4 to 20 times higher than in unaffected soils. Water‐soluble NO−3 was minimal in the surface soil but peaked in the C horizon (120–180 cm) under the 90‐cm SMS pile, indicating that these soils may have little capacity for retaining NO−3 Concentration profiles of the different solutes reflect their relative mobilities in the soil environment and indicate the potential for effects on subsurface water supplies.
Effects of Sample Storage on Biosolids Compost Stability and Maturity Evaluation
Authors: Wu L. , Ma L. Q.
Published: June 2010

Compost stability and maturity are important parameters of compost quality. To date, nearly all compost characterization has been performed using samples freshly collected because sample storage can affect compost stability and maturity evaluation. However, sample preservation is sometimes necessary, especially for scientific research purposes. There is little information available on the effects of sample storage on compost stability and maturity. Samples of biosolids compost with different levels of stability and maturity were collected from four compost facilities in Florida (referred to as Register, Winslow, Sunset, and Meadow). Comparisons of CO2evolution, seed germination rate, and water‐soluble organic carbon (WSOC) were made between fresh samples with short storage at 4°C for less than 1 wk and air‐dried or frozen compost samples stored for 1 yr. The effects of storage (air‐dry or frozen) on the measured parameters depended on compost stability and maturity and on the compost material source. Frozen storage reduced the peak CO2evolution of Register samples by 12 to 29%, while accumulated CO2evolution was reduced by 43 to 64% and 110 to 277% with air‐dry and frozen storage, respectively. The storage effect on CO2evolution with more stable compost was inconsistent. Storage did not affect compost phytotoxicity, except for samples from the Sunset facility. Air‐drying reduced the WSOC by up to 35%, and freezing increased it by up to 34%, while both storage methods had no significant effect on samples of low WSOC. Despite all these variations, WSOC had a significant and consistent relation to CO2evolution and seed germination rates withR2of 0.78 and 0.57, respectively, regardless of storage methods.
Phosphorus Flux from Wetland Soils Affected by Long‐Term Nutrient Loading
Authors: Fisher M. M. , Reddy K. R.
Published: June 2010

Wetland soils play a key role in the cycling of nutrients within an ecosystem. Since soils are potentially a source or a sink for inorganic nutrients, it is important to quantify their influence on overlying water quality in order to understand their importance in overall ecosystem nutrient budgets. Laboratory and field studies were performed in the northern Everglades (WCA‐2A) to determine the magnitude of phosphorus (P) flux between the soil and the overlying water column, under various redox conditions. The P flux was estimated using three techniques: intact soil cores, in situ benthic chambers, and porewater equilibrators. There was reasonable agreement between the P flux estimated using intact soil cores and benthic chambers; however, P flux estimates using the porewater equilibrators were considerably lower than the other two techniques. Models of solute flux, based solely on soil physico–chemical characteristics, may substantially underestimate soil–water nutrient exchange processes. Phosphorus flux measured with the intact soil cores varied from 6.5 mg m−2 d−1 near nutrient inflow areas to undetectable flux 4 km away from the inflow. Oxygen consumption varied from 4 mg m−2 d−1 near the inflow to a constant 1 to 2 mg m−2 d−1 at a distance of 4 km from the inflow. Rate of consumption of NO−3–N and SO2−4 showed no significant trend with respect to distance from inflow. Nitrate N and SO4 consumption rates averaged 120 and 130 mg m−2 d−1, respectively. Consumption of O2 was correlated with P flux, whereas NO−3–N and SO2−4 consumption were not.
Implementation of Sulfate Adsorption in the SAFE Model
Authors: Fumoto Tamon , Sverdrup Harald
Published: June 2010

An SO2−4 adsorption submodel has been implemented in the dynamic soil chemistry model SAFE. The submodel calculates pH‐dependent SO2−4 and H+ adsorption to the soil, as well as the net surface charge development due to uneven adsorption of SO2−4 and H+, using the empirical equations derived from an electrostatic model (Extended Constant Capacitance Model, ECCM) of SO2−4 adsorption. The resulting new SAFE model was applied on a roof experiment plot in the Norway spruce [Picea abies (L.) H. Karst.] stand at Solling, Germany, where atmospheric S and N deposition was artificially reduced by the roof construction. The model performance was compared with the previous versions that used a pH‐independent Freudlich model of SO2−4 adsorption or assumed no SO2−4 adsorption. With the ECCM‐based SO2−4 adsorption submodel, SAFE simulated soil solution SO2−4 concentration and base saturation better, in comparison with measured data, than with the previous SO2−4 adsorption formulations. Through the model application, also, need of additional improvement was suggested, such as calibration of mass transfer coefficients.
Cupric Ion Activity in Peat Soil as a Toxicity Indicator for Maize
Authors: McBride M.B.
Published: June 2010

Copper phytotoxicity in soils is difficult to assess because Cu accumulates at and damages roots, and is not readily transferred to shoots. Soil chemical properties strongly influence Cu speciation, so that total soil Cu alone is not a broadly useful indicator of potential toxicity to plants. The present study measured free Cu2+ activity in Cu‐enriched peat soils using the ion selective electrode. The soil Cu2+ activity was related to the severity of phytotoxicity as measured by several indicators in a maize (Zea mays L.) bioassay, including leaf chlorosis, root stunting, and reduced shoot growth and Fe concentration. A soil Cu2+ activity of 10−7.0 to 10−7.5, corresponding to total Cu of about 275 mg/kg in the peat soil, caused phytotoxicity in maize seedlings. It is proposed that Cu2+ activity is more directly related to phytotoxic effects than other soil tests, such as extractions with strong acids or chelating agents, because it is the free Cu2+ in soil solution that has the most direct toxic effects on roots. There was very limited uptake of Cu into maize shoots, and even when Cu2+ activity and total soil Cu were raised into the extreme toxicity range of 10−5 and 4000 mg/kg, respectively, shoot Cu remained less than 35 mg/kg. These results indicate the inadequacy of the USEPA risk assessment of potential for Cu toxicity to crops amended with sewage sludge, which assumed a no‐effect level of maize shoot Cu of 40 mg/kg.
Nickel Increases Susceptibility of a Nickel Hyperaccumulator to Turnip mosaic virus
Authors: Davis Micheal A. , Murphy John F. , Boyd Robert S.
Published: June 2010

Hyperaccumulated Ni can defend plant tissues against herbivores and pathogens. The effectiveness of this defense, however, has not been tested with a viral pathogen. Turnip mosaic virus (TuMV) accumulation was studied in two serpentine species of Streptanthus with different Ni uptake abilities. Plants of a Ni hyperaccumulator, milkwort jewelflower (S. polygaloides Gray), and a non‐hyperaccumulator, plumed jewelflower (S. insignis Jepson), were grown on Ni‐amended and unamended soils. Plants were inoculated with TuMV at three different phenological stages: basal rosette, bolting, and flowering. Susceptibility of experimental plants to TuMV was determined either by the magnitude of TuMV accumulation (measured by indirect enzyme‐linked immunosorbent assay [ELISA]) or by plant survival. Streptanthus polygaloides plants grown on high‐Ni soil were more susceptible to TuMV than low‐Ni S. polygaloides at all three phenological stages. All rosette and pre‐bolt S. insignis plants were infected by TuMV, but survival and TuMV accumulation were not significantly affected by soil Ni. At flowering, only high‐Ni S. polygaloides plants became infected. For S. polygaloides, elevated tissue Ni concentrations enhanced TuMV infection instead of defending plants from the virus. To reduce risks to nearby agricultural crops, future phytoremediation and phytomining operations using this species should incorporate management plans to prevent the creation of artificial reservoirs of TuMV inoculum.
Nitrate Nitrogen in Surface Waters as Influenced by Climatic Conditions and Agricultural Practices
Authors: Randall Gyles W. , Mulla David J.
Published: June 2010

Subsurface tile drainage from row‐crop agricultural production systems has been identified as a major source of nitrate entering surface waters in the Mississippi River basin. Noncontrollable factors such as precipitation and mineralization of soil organic matter have a tremendous effect on drainage losses, nitrate concentrations, and nitrate loadings in subsurface drainage water. Cropping system and nutrient management inputs are controllable factors that have a varying influence on nitrate losses. Row crops leak substantially greater amounts of nitrate compared with perennial crops; however, satisfactory economic return with many perennials is an obstacle at present. Improving N management by applying the correct rate of N at the optimum time and giving proper credits to previous legume crops and animal manure applications will also lead to reduced nitrate losses. Nitrate losses have been shown to be minimally affected by tillage systems compared with N management practices. Scientists and policymakers must understand these factors as they develop educational materials and environmental guidelines for reducing nitrate losses to surface waters.
Phytoremediation of Aged Petroleum Sludge: Effect of Inorganic Fertilizer
Authors: Hutchinson S.L. , Banks M.K. , Schwab A.P.
Published: June 2010

Phytoremediation is a promising new technology that uses higher plants to enhance biodegradation. Nutrient availability is an important factor governing the success of phytoremediation and can be regulated through the addition of fertilizer. A greenhouse study was conducted to assess the importance of nitrogen and phosphorus for the phytoremediation of petroleum sludge. Degradation of total petroleum hydrocarbons (TPH) was quantified for six fertilization rates and three vegetation treatments: bermuda grass [Cynodon dactylon(L.) Pers.], tall fescue (Festuca arundinaceaSchreb.), and an unvegetated control. During the first 6 mo of the experiment, TPH declined by an average of 49% with no significant differences between treatments. After 1 yr, TPH degradation was significantly greater in both vegetated treatments with a mean TPH reduction of 68% for bermuda, 62% for fescue, and 57% for the unvegetated control. Degradation of TPH in the fescue and bermuda treatments was significantly lower in the treatments in which no fertilizer was added or N and P were added simply to maintain plant growth compared with the higher rates of fertilization. For this short‐term, greenhouse experiment, optimal remediation was obtained by fertilization that produced a C to N to P ratio of 100:2:0.2.
Metalaxyl Toxicity, Uptake, and Distribution in Several Ornamental Plant Species
Authors: Wilson P.Chris , Whitwell Ted , Klaine Stephen J.
Published: June 2010

Phytoremediation depends on the ability of plants to tolerate and assimilate contaminants. This research characterized the interaction between several ornamental plant species and the fungicidal active ingredient, metalaxyl [N‐(2,6‐dimethylphenyl)‐N‐(methoxyacetyl)alanine methyl ester]. Species evaluated included sweetflag (Acorus gramineus Sol. ex Aiton), canna (Canna hybrida L. ‘Yellow King Humbert’), parrotfeather [Myriophyllum aquaticum (Vell.) Verdc.], and pickerelweed (Pontederia cordata L.). Metalaxyl tolerance levels for each species were determined by exposing plants for 7 d to solutions containing 0, 5, 10, 25, 50, 75, or 100 mg metalaxyl L−1 aqueous nutrient media. Response endpoints included fresh mass production after 7 d exposure and 7 d post‐exposure and quantum efficiency using dark‐adapted (Fv/Fm) and light‐adapted (fluorescence yields) plants. Metalaxyl uptake and distribution within the plant was determined by growing plants in aqueous nutrient media containing 1.18 × 106 Bq L−1 [14C]metalaxyl (0.909 mg L−1) for 1, 3, 5, or 7 d. Plant tissues were combusted and analyzed by liquid scintillation counting. Metalaxyl had no effects on the endpoints measured, except for fresh mass production of sweetflag at the 75 and 100 mg L−1 treatment levels. However, leaf necrosis was apparent in most species after 5 d exposure to concentrations greater than 25 mg L−1 Metalaxyl removal from the spiked nutrient media ranged from 15 to 60% during the 7‐d exposure period. The majority of metalaxyl removed from the solution was detected within individual plants. In nearly all cases, activity from the radiolabeled pesticide accumulated in the leaves. Uptake of metalaxyl was correlated with water uptake throughout the 7 d. These results suggest that all species examined may be good candidates for incorporation into a phytoremediation scheme for metalaxyl.
Summary of Well Water Sampling in California to Detect Pesticide Residues Resulting from Nonpoint‐Source Applications
Authors: Troiano John , Weaver Don , Marade Joe , Spurlock Frank , Pepple Mark , Nordmark Craig , Bartkowiak Donna
Published: June 2010

This report summarizes well sampling protocols, data collection procedures, and analytical results for the presence of pesticides in ground water developed by the California Department of Pesticide Regulation (DPR). Specific well sampling protocols were developed to meet regulatory mandates of the Pesticide Contamination Prevention Act (PCPA) of 1986 and to provide further understanding of the agronomic, chemical, and geographic factors that contribute to movement of residues to ground water. The well sampling data have formed the basis for the DPR's regulatory decisions. For example, a sampling protocol, the Four‐Section Survey, was developed to determine if reported detections were caused by nonpoint‐source agricultural applications, a determination that can initiate formal review and subsequent regulation of a pesticide. Selection of sampling sites, which are primarily rural domestic wells, was initially based on pesticide use and cropping patterns. Recently, soil and depth‐to‐ground water data have been added to identify areas where a higher frequency of detection is expected. In accordance with the PCPA, the DPR maintains a database for all pesticide well sampling in California with submission required by all state agencies and with invitations for submission extended to all local and federal agencies or other entities. To date, residues for 16 active ingredients and breakdown products have been detected in California ground water as a result of legal agricultural use. Regulations have been adopted for all detected parent active ingredients, and they have been developed regardless of the level of detection.
Immobilization of Nickel and Other Metals in Contaminated Sediments by Hydroxyapatite Addition
Authors: Seaman John C. , Arey J.Samuel , Bertsch Paul M.
Published: June 2010

Batch experiments were conducted to evaluate the ability of hydroxyapatite (HA) to reduce the solubility of metals, including the primary contaminants of concern, Ni and U, from contaminated sediments located on the Department of Energy's Savannah River Site, near Aiken, SC. Hydroxyapatite was added to the sediments at application rates of 0, 5, 15.8, and 50 g kg−1After equilibrating in either 0.02MKCl or 0.01MCaCl2, the samples were centrifuged and the supernatants filtered prior to metal, dissolved organic C, and PO4analyses. The treated soils were then air‐dried and changes in solid‐phase metal distribution were evaluated using sequential extractions and electron‐based microanalysis techniques. Hydroxyapatite was effective at reducing the solubility of U and, to a lesser degree, Ni. Hydroxyapatite was also effective in reducing the solubility of Al, Ba, Cd, Co, Mn, and Pb. Sequential extractions indicate that HA transfers such metals from more chemically labile forms, such as the water‐soluble and exchangeable fractions, by altering solid‐phase speciation in favor of secondary phosphate precipitates. Hydroxyapatite effectiveness was somewhat reduced in the presence of soluble organics that likely increased contaminant metal solubility through complexation. Arsenic and Cr solubility increased with HA addition, suggesting that the increase in pH and competition from PO4reduced sorption of oxyanion contaminants. Energy dispersive x‐ray (EDXA) analysis conducted in the transmission electron microscope (TEM) confirmed that HA amendment sequesters U, Ni, Pb, and possibly other contaminant metals in association with secondary Al‐phosphates.
Removal of Uranium(VI) from Contaminated Sediments by Surfactants
Authors: Gadelle Frederic , Wan Jiamin , Tokunaga Tetsu K.
Published: June 2010

Uranium(VI) sorption onto a soil collected at the Melton Branch Watershed (Oak Ridge National Laboratory, TN) is strongly influenced by the pH of the soil solution and, to a lesser extent, by the presence of calcium, suggesting specific chemical interactions between U(VI) and the soil matrix. Batch experiments designed to evaluate factors controlling desorption indicate that two anionic surfactants, AOK and T77, at concentrations ranging from 60 to 200 mM, are most suitable for U(VI) removal from acidic soils such as the Oak Ridge sediment. These surfactants are very efficient solubilizing agents at low uranium concentrations: ca. 100% U(VI) removal for [U(VI)]o,sorbed = 10−6 mol kg−1 At greater uranium concentrations (e.g., [U(VI)]o,sorbed = ca. 10−5 mol kg−1), the desorption efficiency of the surfactant solutions increases with an increase in surfactant concentration and reaches a plateau of 75 to 80% of the U(VI) initially sorbed. The most probable mechanisms responsible for U(VI) desorption include cation exchange in the electric double layer surrounding the micelles and, to a lesser extent, dissolution of the soil matrix. Limitations associated with the surfactant treatment include loss of surfactants onto the soil (sorption) and greater affinity between U(VI) and the soil matrix at large soil to liquid ratios. Parallel experiments with H2SO4 and carbonate–bicarbonate (CB) solutions indicate that these more conventional methods suffer from strong matrix dissolution with the acid and reduced desorption efficiency with CB due to the buffering capacity of the acidic soil.
Approximating Phosphorus Release from Soils to Surface Runoff and Subsurface Drainage
Authors: McDowell R.W. , Sharpley A.N.
Published: June 2010

Phosphorus application in excess of crop needs has increased the concentration of P in surface soil and runoff and led many states to develop P‐based nutrient management strategies. However, insufficient data are available relating P in surface soil, surface runoff, and subsurface drainage to develop sound guidelines. Thus, we investigated P release from the surface (0–5 cm depth) of a Denbigh silt loam from Devon, U.K. (30–160 mg kg−1 Olsen P) and Alvin, Berks, Calvin, and Watson soils from Pennsylvania (10–763 mg kg−1 Mehlich‐3 P) in relation to the concentration of P in surface runoff and subsurface drainage. A change point, where the slopes of two linear relationships between water‐ or CaCl2–extractable soil P and soil test phosphorus (STP) (Olsen or Mehlich‐3) meet, was evident for the Denbigh at 33 to 36 mg kg−1 Olsen P, and the Alvin and Berks soils at 185 to 190 mg Mehlich‐3 P kg−1 Similar change points were also observed when STP was related to the P concentration of surface runoff (185 mg kg−1) and subsurface drainage (193 mg kg−1). The use of water and CaCl2 extraction of surface soil is suggested to estimate surface runoff P (r2 of 0.92 for UK and 0.86 for PA soils) and subsurface drainage P (r2 of 0.82 for UK and 0.88 for PA soils), and to determine a change point in STP, which may be used in support of agricultural and environmental P management.
Tillage, Intercrop, and Controlled Drainage–Subirrigation Influence Atrazine, Metribuzin, and Metolachlor Loss
Authors: Gaynor J.D. , Tan C.S. , Drury C.F. , Ng H.Y.F. , Welacky T.W. , van Wesenbeeck I.J.
Published: June 2010

Atrazine (6‐chloro‐N2‐ethyl‐N4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine) and metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylethyl)acetamide] have been found with increasing occurrence in rivers and streams. Their continued use will require changes in agricultural practices. We compared water quality from four crop‐tillage treatments: (i) conventional moldboard plow (MB), (ii) MB with ryegrass (Lolium multiflorum Lam.) intercrop (IC), (iii) soil saver (SS), and (iv) SS + IC; and two drainage control treatments, drained (D) and controlled drainage–subirrigation (CDS). Atrazine (1.1 kg a.i. ha−1), metribuzin [4‐amino‐6‐(1,1‐dimethylethyl)‐3‐(methylthio)‐1,2,4‐triazine‐5(4H)‐one] (0.5 kg a.i. ha−1), and metolachlor (1.68 kg a.i. ha−1) were applied preemergence in a band over seeded corn (Zea mays L.) rows. Herbicide concentration and losses were monitored from 1992 to spring 1995. Annual herbicide losses ranged from <0.3 to 2.7% of application. Crop‐tillage treatment influenced herbicide loss in 1992 but not in 1993 or 1994, whereas CDS affected partitioning of losses in most years. In 1992, SS + IC reduced herbicide loss in tile drains and surface runoff by 46 to 49% compared with MB. The intercrop reduced surface runoff, which reduced herbicide transport. Controlled drainage–subirrigation increased herbicide loss in surface runoff but decreased loss through tile drainage so that total herbicide loss did not differ between drainage treatments. Des‐ethyl atrazine [6‐chloro‐N‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine] comprised 7 to 39% of the total triazine loss.
Correlation of Human Olfactory Responses to Airborne Concentrations of Malodorous Volatile Organic Compounds Emitted from Swine Effluent
Authors: Zahn J.A. , DiSpirito A.A. , Do Y.S. , Brooks B.E. , Cooper E.E. , Hatfield J.L.
Published: June 2010

Direct multicomponent analysis of malodorous volatile organic compounds (VOCs) present in ambient air samples from 29 swine (Sus scrofa) production facilities was used to develop a 19‐component artificial swine odor solution that simulated olfactory properties of swine effluent. Analyses employing either a human panel consisting of 14 subjects or gas chromatography were performed on the air stream from an emission chamber to assess human olfactory responses or odorant concentration, respectively. Analysis of the olfactory responses using Fisher's LSD statistics showed that the subjects were sensitive to changes in air concentration of the VOC standard across dilutions differing by approximately 16%. The effect of chemical synergisms and antagonisms on human olfactory response magnitudes was assessed by altering the individual concentration of nine compounds in artificial swine odor over a twofold concentration range while maintaining the other 18 components at a constant concentration. A synergistic olfactory response was observed when the air concentration of acetic acid was increased relative to the concentration of other VOC odorants in the standard. An antagonistic olfactory response was observed when the air concentration of 4‐ethyl phenol was increased relative to the other VOC odorants in the standard. The collective odorant responses for nine major VOCs associated with swine odor were used to develop an olfactory prediction model to estimate human odor response magnitudes to swine manure odorants through measured air concentrations of indicator VOCs. The results of this study show that direct multicomponent analysis of VOCs emitted from swine effluent can be applied toward estimating perceived odor intensity.
Functional Classification of Swine Manure Management Systems Based on Effluent and Gas Emission Characteristics
Authors: Zahn J.A. , Hatfield J.L. , Laird D.A. , Hart T.T. , Do Y.S. , DiSpirito A.A.
Published: June 2010

Gaseous emissions from swine (Sus scrofa) manure storage systems represent a concern to air quality due to the potential effects of hydrogen sulfide, ammonia, methane, and volatile organic compounds on environmental quality and human health. The lack of knowledge concerning functional aspects of swine manure management systems has been a major obstacle in the development and optimization of emission abatement technologies for these point sources. In this study, a classification system based on gas emission characteristics and effluent concentrations of total phosphorus (P) and total sulfur (S) was devised and tested on 29 swine manure management systems in Iowa, Oklahoma, and North Carolina in an effort to elucidate functional characteristics of these systems. Four swine manure management system classes were identified that differed in effluent concentrations of P and S, methane (CH4) emission rate, odor intensity, and air concentration of volatile organic compounds (VOCs). Odor intensity and the concentration of VOCs in air emitted from swine manure management systems were strongly correlated r2=0.88 The concentration of VOC in air samples was highest with outdoor swine manure management systems that received a high input of volatile solids (Type 2). These systems were also shown to have the highest odor intensity levels. The emission rate for VOCs and the odor intensity associated with swine manure management systems were inversely correlated with CH4 and ammonia (NH3) emission rates. The emission rates of CH4, NH3, and VOCs were found to be dependent upon manure loading rate and were indirectly influenced by animal numbers.
Denitrification Losses from Outdoor Piglet Production: Spatial and Temporal Variability
Authors: Petersen S.O. , Kristensen K. , Eriksen J.
Published: June 2010

Animal welfare considerations have stimulated the development of outdoor piglet (Sus scrofa) production systems, but the high levels of nutrients excreted suggest that nutrient losses from this system may be high. This study first described the spatial distribution of denitrification activity in a 5‐ × 5‐m grid within and outside a paddock immediately after the sows (32 sows ha−1 for 6 mo) were removed in October 1997, and again the following March. Denitrification rates averaged 0.01 kg N ha−1 d−1 outside, and 0.5 kg N ha−1 d−1 inside the paddock in October, while the corresponding figures in March were 0.01 and 0.1 kg N ha−1 d−1 The highest denitrification rates were observed around the feeder, and this was also the case for concentrations of dissolved organic C and inorganic N in the soil. A statistical model that included both soil parameters and distance to feeder and huts gave the best description of the variability, but there was no significant autocorrelation between sampling points. In a second phase, seasonal variation of denitrification activity within a paddock (12 sows ha−1 yr−1) was quantified; 10 soil cores were sampled along a transect 11 times between March 1998 and February 1999. There was a significant positive effect of dissolved organic carbon (DOC) on denitrification at <25% gravimetric soil moisture (i.e., to November in this study). Both climate and management (position of huts and feeder) appeared to influence denitrification, which was estimated to be 69 kg N ha−1 yr−1, or 11% of the N surplus of this production system.
Selenium Distribution and Fluxes in Intertidal Wetlands, San Francisco Bay, California
Authors: Zawislanski P.T. , Mountford H.S. , Gabet E.J. , McGrath A.E. , Wong H.C.
Published: June 2010

Selenium (Se) concentrations exceeding ecological guidelines for sediments and suspended particulate matter (SPM) have been observed in the northern reach of the San Francisco Bay estuary. Long‐term availability of elevated Se in wetland sediments depends in part on the fluxes controlling Se distribution. The relative contribution of sedimentary vs. post‐depositional Se fluxes in two San Francisco Bay intertidal wetlands was estimated. Selenium concentrations on surface wetland sediments were compared with levels on SPM, and with previously established background levels in San Francisco Bay sediments. Sediment Se fluxes to the wetlands were measured directly using sediment traps. Although dissolved Se concentrations are higher than particulate Se concentrations in San Francisco Bay water, sediment input into the system provides the major flux of Se. Strong correlation between Se and C on SPM (r2 = 0.81) indicates the importance of organic particulate deposition. Dependence on sediment texture was qualitatively established by measuring Se on particle‐size separates. Normalization to Al showed that 65% of Se spatial variability is related to sediment texture. Selenium is further enriched in the marsh via post‐depositional inputs, probably due to in situ adsorption from overlying water and chemical reduction. According to sediment flux measurements, enrichment in the marsh is equivalent to 20 to 25% of the particulate Se flux, thereby defining the marsh as a Se sink. These findings highlight the need for more intensive monitoring of SPM as the major source of Se to intertidal wetlands.
Profenofos Residues in Wild Fish from Cotton‐Growing Areas of New South Wales, Australia
Authors: Kumar A. , Chapman John C.
Published: June 2010

The organophosphorus (OP) pesticide profenofos (O‐4‐bromo‐2‐chlorophenyl O‐ethyl S‐propyl phosphorothioate) is used heavily in cotton‐growing areas of eastern Australia toward the end of the growing season. European carp (Cyprinus carpio), bony bream (Nematalosa erebi), and mosquitofish (Gambusia holbrooki) were collected from the cotton‐growing areas around Wee Waa, New South Wales, to determine the relationship between profenofos residues and acetylcholinesterase (AChE) activity in wild fish. Profenofos concentrations in water, sediment, and fish tissue reflected its general level of use; levels in March 1994 were significantly higher than in 1993 and generally decreased in May, 6 wk after cessation of spraying. Residues in carp and bony bream generally correlated with concentrations in water and sediment, although residues in fish tend to persist longer at some sites. Acetylcholinesterase inhibition was a useful indicator of profenofos exposure within a season, particularly if linked with residue measurements. Bony bream and gravid female mosquitofish recovered AChE levels more slowly than carp or nongravid mosquitofish. Recovery in creeks was generally more rapid than in lagoons.
Availability of Arsenic, Copper, Lead, Thallium, and Zinc to Various Vegetables Grown in Slag‐Contaminated Soils
Authors: Bunzl K. , Trautmannsheimer M. , Schramel P. , Reifenhäuser W.
Published: June 2010

To anticipate a possible hazard resulting from the plant uptake of metals from slag‐contaminated soils, it is useful to study whether vegetables exist that are able to mobilize a given metal in the slag to a larger proportion than in an uncontaminated control soil. For this purpose, we studied the soil to plant transfer of arsenic, copper, lead, thallium, and zinc by the vegetables bean (Phaseolus vulgaris L. ‘dwarf bean Modus’), kohlrabi (Brassica oleracea var. gongylodes L.), mangold (Beta vulgaris var. macrorhiza), lettuce (Lactuca sativa L. ‘American gathering brown’), carrot (Daucus carota L. ‘Rotin’, ‘Sperlings’s'), and celery [Apium graveiolus var. dulce (Mill.) Pers.] from a control soil (Ap horizon of a Entisol) and from a contaminated soil (1:1 soil–slag mixtures). Two types of slags were used: an iron‐rich residue from pyrite (FeS2) roasting and a residue from coal firing. The metal concentrations in the slags, soils, and plants were used to calculate for each metal and soil–slag mixture the plant–soil fractional concentration ratio (CRfractional,slag), that is, the concentration ratio of the metal that results only from the slag in the soil. With the exception of Tl, the resulting values obtained for this quantity for As, Cu, Pb, and Zn and for all vegetables were significantly smaller than the corresponding plant–soil concentration ratios (CRcontrol soil) for the uncontaminated soil. The results demonstrate quantitatively that the ability of a plant to accumulate a given metal as observed for a control soil might not exist for a soil–slag mixture, and vice versa.
Tillage and Nutrient Source Effects on Surface and Subsurface Water Quality at Corn Planting
Authors: Zhao Suling L. , Gupta Satish C. , Huggins David R. , Moncrief John F.
Published: June 2010

This study quantified the effects of tillage (moldboard plowing [MP], ridge tillage [RT]) and nutrient source (manure and commercial fertilizer [urea and triple superphosphate]) on sediment, NH4+–N, NO−3–N, total P, particulate P, and soluble P losses in surface runoff and subsurface tile drainage from a clay loam soil. Treatment effects were evaluated using simulated rainfall immediately after corn (Zea mays L.) planting, the most vulnerable period for soil erosion and water quality degradation. Sediment, total P, soluble P, and NH+4–N losses mainly occurred in surface runoff. The NO−3–N losses primarily occurred in subsurface tile drainage. In combined (surface and subsurface) flow, the MP treatment resulted in nearly two times greater sediment loss than RT (P < 0.01). Ridge tillage with urea lost at least 11 times more NH+4–N than any other treatment (P < 0.01). Ridge tillage with manure also had the most total and soluble P losses of all treatments (P < 0.01). If all water quality parameters were equally important, then moldboard plow with manure would result in least water quality degradation of the combined flow followed by moldboard plow with urea or ridge tillage with urea (equivalent losses) and ridge tillage with manure. Tillage systems that do not incorporate surface residue and amendments appear to be more vulnerable to soluble nutrient losses mainly in surface runoff but also in subsurface drainage (due to macropore flow). Tillage systems that thoroughly mix residue and amendments in surface soil appear to be more prone to sediment and sediment‐associated nutrient (particulate P) losses via surface runoff.
Revegetation of an Abandoned Uranium Millsite on the Colorado Plateau, Arizona
Authors: Glenn E.P. , Waugh W.J. , Moore D. , McKeon C. , Nelson S.G.
Published: June 2010

We attempted to restore native plants on disturbed sites at a former uranium mill on the Colorado Plateau near Tuba City, AZ. Four‐wing saltbush [Atriplex canescens (Pursh) Nutt.] was successfully established in compacted caliche soil and in unconsolidated dune soil when transplants were irrigated through the first summer with 20 L/plant/wk. The caliche soil was ripped before planting to improve water‐holding capacity. The diploid saltbush variety, angustifolia, had higher survival and growth than the common tetraploid variety, occidentalis, especially on dune soil. The angustifolia variety grew to 0.3 to 0.4 m3 per plant over 3 yr even though irrigation was provided only during the establishment year. By contrast, direct seeding of a variety of native forbs, grasses, and shrubs yielded poor results, despite supplemental irrigation throughout the first summer. In this arid environment (precipitation = 100 to 200 mm/yr), the most effective revegetation strategy is to establish keystone native shrubs, such as four‐wing saltbush, using transplants and irrigation during the establishment year, rather than attempting to establish a diverse plant community all at once.
Influence of Plant Growth on Degradation of Linear Alkylbenzene Sulfonate in Sludge‐Amended Soil
Authors: Mortensen G.K. , Egsgaard H. , Ambus P. , Jensen E.S. , Gr⊘n C.
Published: June 2010

Widespread application of sewage sludge to agricultural soils in Denmark has led to concern about the possible accumulation and effects of linear alkylbenzene sulfonate (LAS) in the soil ecosystem. Therefore, we have studied the uptake and degradation of LAS in greenhouse pot experiments. Sewage sludge was incorporated into a sandy soil to give a range from very low to very high applications (0.4 to 90 Mg dry wt. ha−1). In addition, LAS was added as water solutions. The soil was transferred to pots and sown with barley (Hordeum vulgare L. cv. Apex), rape (Brassica napus L. cv. Hyola 401), or carrot (Daucus carota L.). Also, plant‐free controls were established. For all additions there was no plant uptake above the detection limit at 0.5 mg LAS kg−1 d.w, but plant growth stimulated the degradation. With a growth period of 30 d, LAS concentrations in soil from pots with rape had dropped from 27 to 1.4 mg kg−1 dry wt., but in plant‐free pots the concentration decreased only to 2.4 mg kg−1 dry wt. When LAS was added as a spike, the final concentration in soil from planted pots was 0.7 mg kg−1 dry wt., but in pots without plants the final concentration was much higher (2.5 mg kg−1 dry wt.). During degradation, the relative fraction of homologues C10, C11, and C12 decreased, while C13 increased.
Radionuclide Transport above a Near‐Surface Water Table: III. Soil Migration and Crop Uptake of Three Gamma‐Emitting Radionuclides, 1990 to 1993
Authors: Wadey P. , Shaw G. , Bell J.N.B.
Published: June 2010

This paper summarizes the vertical distributions of 22Na, 137Cs, and 60Co above controlled water tables in deep and shallow lysimeters during a four‐year experiment. The activity concentration profiles were all determined at the time of harvest of a winter wheat (Triticum aestivum L. cv. Pastiche) crop. Activity concentrations in different crop tissues were determined and crop uptake expressed as both an inventory ratio (IR) and a transfer factor (TFw), weighted to account for root and radionuclide distributions within the soil profile. Experimental variates were subjected to analysis of variance to determine the single and combined effects of the soil depth and the year of the experiment on the results obtained. Each radionuclide showed significant variations in activity concentration with soil depth, but the significance of these variations from year to year was dependent on radionuclide. A distinction in the behavior of weakly sorbed (22Na) and more highly sorbed (137Cs and 60Co) radionuclides was observed. The former exhibited significant variations in its distribution in the soil profile from year‐to‐year whereas the latter did not. Relatively high TFw values for 22Na were maintained throughout the experiment, whereas for 137Cs and 60Co, the highest TFw values were recorded in 1990 followed by a significant decline in 1991, with TFw remaining low in 1992 and 1993. The TFw values were, in general, significantly higher for deep lysimeters than for shallow lysimeters. This is thought to provide evidence of enhanced radionuclide absorption by the relatively small fraction of roots in the vicinity of the deeper water table.
Decomposition and Nitrogen Mineralization from Biosolids and Other Organic Materials: Relationship with Initial Chemistry
Authors: Rowell Douglas M. , Prescott Cindy E. , Preston Caroline M.
Published: June 2010

Biosolids are effective forest fertilizers. In order to facilitate their use it is important that one be able to predict the amount and rate of mineralization of nutrients, particularly nitrogen, and the relationship between substrate chemistry and N release. We examined the relationships between substrate quality and nitrogen release in a variety of organic materials. Rates of decomposition and net N mineralization from four biosolids, wheat straw, paper fines, and Douglas‐fir [Pseudotsuga menziesii (Mirb.) Franco] needle litter were measured during 391‐d incubations in a greenhouse, and at two field sites in wet coastal and dry interior forests. Decomposition rates were best predicted by a model incorporating the ratio of carbon to organic matter. The decomposition model extrapolated well to the field when site‐specific correction factors were applied. There was a weak relationship between rates of decomposition and net N mineralization. Rates of net N mineralization were best predicted by a model incorporating the initial organic N concentration and the proportion of phenolic C determined from solid‐state 13C nuclear magnetic resonance (NMR) spectroscopy. The mineralization model extrapolated less well to the field, but the effect of substrate chemistry was still apparent. Among the four biosolids there was a strong correlation between organic N concentration and indices of protein determined from 13C NMR, suggesting that these protein indices may be useful for predicting N mineralization from biosolids. There was some evidence that the protein content and N mineralization in biosolids may be predictable from the sewage treatment process employed.
Manure Sampling for Nutrient Analysis: Variability and Sampling Efficacy
Authors: Dou Z. , Galligan D.T. , Allshouse R.D. , Toth J.D. , Ramberg C.F. , Ferguson J.D.
Published: June 2010

Reliable estimation of nutrient concentrations is required to manage animal manure for protecting waters while sustaining crop production. This study was conducted to investigate sample variability and reliable nutrient analysis for several manure types and handling systems. Serial samples were collected from dairy, swine, and broiler poultry operations while manure was being loaded onto hauler tanks or spreaders for field application. Samples were analyzed for total solids (TS), total nitrogen (N), ammoniacal nitrogen (NH4–N), total phosphorus (P), and potassium (K). The least number of samples needed for reliable testing of total N and P, defined as ±10% of the experimental means with 99% probability, was obtained for each farm using a computer‐intensive random resampling technique. Sample variability within farms, expressed as the coefficient of variation (CV), was mostly 6 to 8% for farms that used agitation of manure storages but several times higher (20–30%) on farms where no agitation was applied during the sampling period. Results from the random resampling procedure indicated that for farms that used agitation, three to five samples were adequate for a representative composite for reliable testing of total N and P; whereas for farms without agitation, at least 40 samples would be required. Data also suggest that using book values for manure nutrient estimations could be problematic because the discrepancies between book standards and measured farm data varied widely from a small amount to several fold.
Statistical Evaluation of Geochemical Parameter Distribution in a Ground Water System Contaminated with Petroleum Hydrocarbons
Authors: Lee Jin‐Yong , Cheon Jeong‐Yong , Lee Kang‐Kun , Lee Seok‐Young , Lee Min‐Hyo
Published: June 2010

A shallow‐depth ground water area was investigated to identify the dominant processes governing the distribution of hydrocarbon contaminants and hydrogeochemical parameters. The ground water in the study site has been highly contaminated with petroleum hydrocarbons. A preliminary pump‐and‐treatment remediation technology was applied for 4 yr at the site. Multivariate analyses were applied to hydrogeochemical data obtained before and after the rainy season. The pump‐and‐treatment application, indigenous biodegradation, and mixing by precipitation recharge are the major factors or events involved in the distribution of geochemical parameters of the ground water in the study area. Site‐specific artificial pavement also played an important role in the evolution of the ground water chemistry. A conventional graphical analysis method (Piper plot) of major ions did not effectively reveal these effects. In this study, we demonstrate the usefulness of multivariate analysis (factor and cluster analyses) using biodegradation indicator parameters, as well as major cations and anions, for the study of the ground water system in the hydrocarbon‐contaminated site.