bluuebunny/crossref_metadata_2025 huggingface dataset:
Geographic Variability of Escherichia coli Ribotypes from Animals in Idaho and Georgia
Authors: Hartel Peter G. , Summer Jacob D. , Hill Jennifer L. , Collins J. Victoria , Entry James A. , Segars William I.
Published: June 2010

Several genotypic methods have been developed for determining the host origin of fecal bacteria in contaminated waters. Some of these methods rely on a host origin database to identify environmental isolates. It is not well understood to what degree these host origin isolates are geographically variable (i.e., cosmopolitan or endemic). This is important because a geographically limited host origin database may or may not be universally applicable. The objective of our study was to use one genotypic method, ribotyping, to determine the geographic variability of the fecal bacterium, Escherichia coli, from one location in Idaho and three locations in Georgia for cattle (Bos taurus), horse (Equus caballus), swine (Sus scrofa), and chicken (Gallus gallus domesticus). A total of 568 fecal E. coli isolates from Kimberly, ID (125 isolates), Athens, GA (210 isolates), Brunswick, GA (102 isolates), and Tifton, GA (131 isolates), yielded 213 ribotypes. The percentage of ribotype sharing within an animal species increased with decreased distance between geographic locations for cattle and horses, but not for swine and chicken. When the E. coli ribotypes among the four host species were compared at one location, the percent of unshared ribotypes was 86, 89, 81, and 79% for Kimberly, Athens, Brunswick, and Tifton, respectively. These data suggest that there is good ribotype separation among host animal species at each location. The ability to match environmental isolates to a host origin database may depend on a large number of environmental and host origin isolates that ideally are not geographically separated.
Phosphorus Saturation in Spodosols Impacted by Manure
Authors: Nair V.D. , Graetz D.A.
Published: June 2010

Significant amounts of phosphorus (P) accumulate in soils receiving animal manures that could eventually result in unacceptable concentrations of dissolved P loss through surface runoff or subsurface leaching. The degree of phosphorus saturation (DPS) relates a soil's extractable P to its P sorbing capacity, and is reportedly a predictor of the P likely to be mobilized from a system. A DPS value (DPS‐1) was derived that expressed the percentage of Mehlich 1–extractable P to the sorbing capacity of a Spodosol (expressed as the sum of oxalate‐extractable Fe and Al). Values of DPS‐1 were determined in various horizons of soil in current and abandoned dairy systems in South Florida's Lake Okeechobee watershed to assess P release potential. Land use within the dairies was classified as highly impacted by cattle (intensive and holding), and minimally impacted by cattle (pasture, forage, or native) areas. The A and E horizon of soils in heavily manure‐impacted intensive and holding areas for both active and abandoned dairies generally had higher DPS‐1 values than the pasture, forage, and native area soils, which were minimally impacted by manure. Degree of P saturation was also calculated as a percentage of Mehlich 1–extractable P to the sum of Mehlich 1–extractable Fe and Al (DPS‐2). Both DPS‐1 and DPS‐2 were shown to be significantly (P = 0.0001) related to water‐extractable P for all soil horizons, suggesting that either index can be used as an indicator for P loss potential from a soil.
Environmental Mapping Based on Spatial Variability
Authors: Kovalevskaya Nelley , Pavlov Vladimir
Published: June 2010

Environmental maps show the probable environmental states of different types of land use or development of landscape in a geographic context. Remotely sensed data are particularly efficient for environmental mapping in order to outline major environmental types. Multiple schemes of image classification used in environmental mapping are either traditionally statistical or heuristic. While the former methods do not take account of spatial variability in space and aerial data, the latter ones does not lend themselves to optimal solutions we present. Novel probabilistic models of piecewise‐homogeneous images are used in environmental mapping to segment real images. The models consider both an image and a land cover map. Such a pair constitutes an example of a Markov random field specified by a joint Gibbs probability distribution of images and maps. Parameters of the model are estimated by using a stochastic approximation technique. Its convergence to the desired values is studied experimentally. Addition of spatial attributes appears to be necessary in most areas where the differences in spatial data between regions in the image occur. Experiments in generating the pairs of images and environmental maps and in segmenting the simulated as well as real images are discussed.
Relationships between Stream Size, Suspended Particles, and Filter‐Feeding Macroinvertebrates in a Great Plains Drainage Network
Authors: Whiles Matt R. , Dodds Walter K.
Published: June 2010

Suspended fine particles (seston) are an important component of energy and nutrient cycling in streams, but they can also be pollutants. We examined seston dynamics and filter‐feeding macroinvertebrate communities in sites representing headwaters to large rivers in the Kansas River drainage, northeastern KS. Seston samples were collected at least seasonally during low to moderate flows for one year beginning in the summer of 1999, and quality was assessed by determining organic content and C to N ratio. A rapid bioassessment approach was used to examine filter‐feeders. Relationships between stream size and seston concentrations were markedly influenced by anthropogenic activities. There was no relationship between total seston concentration and stream size across all sites (r= 0.14,p> 0.05), but a significant, positive relationship was evident when impounded and suburban sites were excluded (r= 0.73,p< 0.01); this same trend was evident for organic and inorganic components. Seasonal patterns of C to N ratio were evident, with generally lower values during winter and highest values in summer. However, seasonal patterns were dampened in suburban sites and virtually absent below impoundments. Filter‐feeder richness was correlated with average organic seston concentrations (r= 0.8,p< 0.01), but this relationship was also obscured by impoundments and suburban development. In particular, impoundments had a dramatic, negative effect on richness. Abundance of most hydropsychid caddisfly taxa was positively correlated with organic seston concentration. Results indicate there are significant patterns regarding seston, filter‐feeders, and stream size in this Great Plains river system, but patterns are strongly influenced by human activities. These relationships are relevant to management issues regarding suspended particles and the potential development of bioassessment techniques.
Sorption and Degradation Characteristics of Phosmet in Two Contrasting Australian Soils
Authors: Suter H. C. , White R. E. , Heng L. K. , Douglas L. A.
Published: June 2010

The organophosphate insecticide phosmet [phosphorodithioic acid, s‐((1,3‐dihydro‐1,3‐dioxo‐2H‐isoindol‐2yl)methyl), o,o‐dimethyl ester] is used to control red‐legged earth mites (Halotydeus destructor), lucerne flea (Sminthurus viridis), and Oriental fruit moth (Cydia molesta) in horticulture and vegetable growing. This study was undertaken with two soils of contrasting properties to determine the extent to which sorption and degradation of the insecticide might influence its potential to leach from soil into receiving waters. Two soils were used: a highly organic, oxidic clay soil (Ferrosol) and a sandy soil low in organic matter (Podosol), sampled to 0.3 m depth. The extent of sorption and decomposition rate of a phosmet commercial formulation were measured in laboratory experiments. Sorption followed a Freundlich isotherm at all depths. The Freundlich coefficient K was significantly correlated (p = 0.005) with organic C content in the Podosol, and significantly correlated (p = 0.005) with organic C and clay content in the Ferrosol. K was highest (48.8 L kg−1) in the 0‐ to 0.05‐m depth of the Ferrosol, but lowest (1.0 L kg−1) at this depth in the Podosol. Degradation followed first‐order kinetics, with the phosmet half‐life ranging from 14 h (0–0.05 m depth) to 187 h (0.2–0.3 m depth) in the Ferrosol. The half‐life was much longer in the sandy Podosol, ranging from 462 to 866 h, and did not change significantly with depth. Soil organic C and to a lesser degree clay content influenced phosmet sorption and degradation, but the interaction was complex and possibly affected by co‐solvents present in the commercial formulation.
Sorption Interactions between Imazaquin and a Humic Acid Extracted from a Typical Brazilian Oxisol
Authors: Ferreira Julieta A. , Martin‐Neto Ladislau , Vaz Carlos M. P. , Regitano Jussara B.
Published: June 2010

Soil sorption of most hydrophobic organic compounds (e.g., nonpolar pesticides) is directly related to soil organic matter (SOM) content. Humic substances are the major SOM components, containing carboxylic, phenolic, amine, quinone, and other functional groups, and specific structural configurations. In this paper, sorption interactions between imazaquin (2‐[4,5‐dydro‐4‐methyl‐4‐(1‐methylethyl)‐5‐oxo‐1H‐imidazol‐2‐yl]‐3‐quinoline‐carboxylic acid) herbicide (IM) and a humic acid (HA) extracted from a typical Brazilian Oxisol were studied with electron paramagnetic resonance (EPR) and Fourier‐transform infrared (FTIR) spectroscopic techniques. A polarographic technique was used to quantify sorption. The IM amount sorbed on the HA was much higher than that on the whole soil within the pH range studied, emphasizing the prominent role played by SOM on IM sorption. Moreover, IM sorption increased as the soil‐solution pH decreased. This enhancement in sorption was attributed to the hydrophobic affinity of the herbicide by the HA and to the electrostatic interaction between the protonated quinoline group of IM and the negative sites of the HA. Hydrophobic regions in the HA's interior at low pH (<5.0) were recently demonstrated by an EPR detectable spin‐label molecule. The FTIR and EPR spectroscopy and polarography data indicated weak interaction between IM and the soil and its HA, involving hydrogen bonding, proton transfer, and cation exchange (at low pH), and mainly hydrophobic interactions. However, no strong reaction mechanism, such as charge transfer, was involved. In addition, this research suggested that soil amendment with organic material might increase magnitude of IM sorption, consequently avoiding leaching and carryover problems usually found for mobile and persistent herbicides such as imazaquin.
Basal Area Growth of Sugar Maple in Relation to Acid Deposition, Stand Health, and Soil Nutrients
Authors: Duchesne Louis , Ouimet Rock , Houle Daniel
Published: June 2010

Previous studies have shown in noncalcareous soils that acid deposition may have increased soil leaching of basic cations above the input rate from soil weathering and atmospheric depositions. This phenomenon may have increased soil acidity levels, and, as a consequence, may have reduced the availability of these essential nutrients for forest growth. Fourteen plots of the Forest Ecosystem Research and Monitoring Network in Québec were used to examine the relation between post‐industrial growth trends of sugar maple (Acer saccharum Marsh.) and acid deposition (N and S), stand decline rate, and soil exchangeable nutrient concentrations. Atmospheric N and S deposition and soil exchangeable acidity were positively associated with stand decline rate, and negatively with the average tree basal area increment trend. The growth rate reduction reached on average 17% in declining stands compared with healthy ones. The results showed a significant sugar maple growth rate reduction since 1960 on acid soils. The appearance of the forest decline phenomenon in Québec can be attributed, at least partially, to soil acidification and acid deposition levels.
Ion Partitioning among Soil and Plant Components under Drip, Furrow, and Sprinkler Irrigation Regimes
Authors: Wang D. , Shannon M. C. , Grieve C. M. , Shouse P. J. , Suarez D. L.
Published: June 2010

Soil and water resources can be severely degraded by salinity when total salt input exceeds output in irrigated agriculture. This study was conducted to examine partitioning of Ca2+, Na+, and Cl− between soil and soybean [Glycine max (L.) Merr.] plants under different irrigation regimes with both field and modeling assessments. In drip and sprinkler treatments, the irrigation water was salinized with NaCl and CaCl2 salts to simulate a Cl− and Na+ dominant saline drainage water. In the furrow irrigation treatment, the soil was salinized, prior to planting, with NaCl and CaCl2 salts to simulate a Cl− and Na+ dominant saline soil. A total of 756 soil and 864 plant samples were collected and analyzed for the salt ions to obtain ion partitioning and mass balance assessments. Modeling of salt ion uptake by plants and distribution in the soil profile was performed with a two‐dimensional solute transport model for the three irrigation regimes. Results indicated that about 20% of the applied Ca2+ was recovered in harvested soybean biomass in all treatments. Plant uptake of either Na+ or Cl− was less than 0.5% in the drip and furrow, and about 2% in the sprinkler irrigation treatment. Significant increases in soil salinity were found in the sprinkler plot that received the highest cumulative amount of salts. Simulated ion distributions in the soil were comparable with the measurements. Compared with the total seasonal salt input, mass balances between 65 and 108% were obtained. Most salt inputs accumulate in the soil, and need to be removed periodically to prevent soil salinization.
Sorption and Transport Behavior of Naphthalene in an Aggregated Soil
Authors: Lee Jaehoon , Hundal Lakhwinder S. , Horton Robert , Thompson Michael L.
Published: June 2010

Soil solution chemistry influences the sorption and transport behavior of hydrophobic organic compounds (HOCs) in soil. We used both batch and column studies to investigate the influence of ionic strengths (0.03 and 1.5 M) and flow velocities (12 and 24 cm h−1) on sorption and transport of naphthalene (NAP) in aggregated soil. Sorption parameters such as the Freundlich coefficient (Kf) and exponent (n) calculated from batch studies and column experiments were also compared. Retardation of NAP transport was greater at higher solution ionic strength, which may be attributed to greater sorption affinity due to enhanced aggregation of the sorbent. The effect of ionic strength on sorption of NAP observed in the batch study was consistent with the results from the column study. The Kf and n values obtained from the batch study for the two ionic strengths ranged from 7.8 to 13.7 and 0.68 to 0.80, respectively, whereas the Kf and n values obtained from the column study ranged from 7.9 to 9.9 and 0.73 to 0.85, respectively. The effluent breakthrough curve (BTC) of NAP at a flow rate of 24 cm h−1 showed significant chemical and physical nonequilibrium behavior, implying that a considerable amount of sorption in aggregated soil was time dependent when flow was relatively fast. The BTCs calculated with the parameters determined from batch studies compared poorly with the measured BTCs. The potential for nonequilibrium transport should be incorporated in models used for predicting the fate and transport of HOCs. Furthermore, caution is required when extrapolating the results from batch studies, especially for aggregated soils.
Design and Performance of a Dynamic Gas Flux Chamber
Authors: Reichman Rivka , Rolston Dennis E.
Published: June 2010

Chambers are commonly used to measure the emission of many trace gases and chemicals from soil. An aerodynamic (flow through) chamber was designed and fabricated to accurately measure the surface flux of trace gases. Flow through the chamber was controlled with a small vacuum at the outlet. Due to the design using fans, a partition plate, and aerodynamic ends, air is forced to sweep parallel and uniform over the entire soil surface. A fraction of the air flowing inside the chamber is sampled in the outlet. The air velocity inside the chamber is controlled by fan speed and outlet suction flow rate. The chamber design resulted in a uniform distribution of air velocity at the soil surface. Steady state flux was attained within 5 min when the outlet air suction rate was 20 L/min or higher. For expected flux rates, the presence of the chamber did not affect the measured fluxes at outlet suction rates of around 20 L/min, except that the chamber caused some cooling of the surface in field experiments. Sensitive measurements of the pressure deficit across the soil layer in conjunction with measured fluxes in the source box and chamber outlet show that the outflow rate must be controlled carefully to minimize errors in the flux measurements. Both over‐ and underestimation of the fluxes are possible if the outlet flow rate is not controlled carefully. For this design, the chamber accurately measured steady flux at outlet air suction rates of approximately 20 L/min when the pressure deficit within the chamber with respect to the ambient atmosphere ranged between 0.46 and 0.79 Pa.
Application Technique and Slurry Co‐Fermentation Effects on Ammonia, Nitrous Oxide, and Methane Emissions after Spreading
Authors: Wulf S. , Maeting M. , Clemens J.
Published: June 2010

Ammonia emissions after spreading animal manure contribute a major share to N losses from agriculture. There is an increasing interest in anaerobic co‐digestion of liquid manure with organic additives. This fermentation results in a change of physical and chemical parameters of the slurry. Among these are an increased pH and ammonium content, implying a higher risk of NH3 losses from fermentation products. To compare different application techniques and the effect of fermentation on NH3 volatilization, we used the standard comparison method and tested it for reliability. This method seems to be perfectly suited for experiments with a large number of treatments and replicates if prerequisites concerning the experimental layout are considered. We tested four different application techniques on arable and grassland sites. The more the substrate was incorporated into the soil or applied near the soil surface on the grassland site, the less NH3 was lost. Injection of the substrate reduced losses to less than 10% of applied NH+4 on both sites, whereas losses after splash plate application amounted to more than 30%. Trail shoe application on grassland performed as well as injection. Harrowing on arable land also reduced emissions efficiently, if harrowing occurred within the first 2 h after application. Emissions from trail hose–applied co‐fermentation product were not greater than from unfermented slurry. Better infiltration of the less viscous substrate seemed to have compensated for the increased loss potential.
Mapping the Probability of Exceeding Critical Thresholds for Cadmium Concentrations in Soils in the Netherlands
Authors: Brus D. J. , de Gruijter J. J. , Walvoort D. J. J. , de Vries F. , Bronswijk J. J. B. , Römkens P. F. A. M. , de Vries W.
Published: June 2010

The probability of exceeding critical thresholds of Cd concentrations in the soil was mapped at a national scale. The critical thresholds in soil were based on food quality criteria for Cd in crops or in organs of cattle (Bos taurus), and were calculated by inverting a regression model for the Cd concentration in the crop, with the Cd concentration in soil, soil organic matter (SOM) content, clay content, and pH as predictors. The probability of exceeding the critical threshold for Cd in soil per node of a 500‐ × 500‐m grid was approximated by Monte Carlo simulation, using the estimated cumulative distribution functions (cdf) of SOM, clay, pH, and Cd as input. The cdfs were estimated by simple indicator kriging with local prior means. For SOM, clay, and pH, detailed maps of soil type and land use were used to define subregions with assumed constant local means of the indicators (a priori distributions). The cdfs were sampled by Latin hypercube sampling. We accounted for correlation between the actual and critical Cd concentrations in soil by drawing Cd values from cdfs conditional on SOM and clay. The estimated probability for grassland is negligible, even in areas with high Cd concentrations in soil, and for maize (Zea maysL.) land the probability is almost everywhere smaller than 5%. For arable soils, however, these probabilities commonly are larger than 5% when sugar beet (Beta vulgarisL.) or wheat (Triticum aestivumL.) is taken as a reference crop, and locally exceed 50%.
Soil and Tree‐Ring Chemistry Response to Liming in a Sugar Maple Stand
Authors: Houle Daniel , Duchesne Louis , Moore Jean‐David , Laflèche Marc Richer , Ouimet Rock
Published: June 2010

An evaluation of the impact of dolomitic lime [CaMg(CO3)2] on soils (five years after treatment) and sapwood chemistry (after four growing seasons) was realized for a Ca‐deficient sugar maple stand at the lake Clair watershed. The effect on humus chemistry was significant: exchangeable Mg and Ca, effective acidity (EA), base saturation (BSe), pH, and effective cation exchange capacity (CECe) significantly increased, while exchangeable Fe significantly decreased. In the B horizon, liming increased exchangeable Ca, Mg, and Mn concentrations while decreasing other acid cations. No significant temporal trends in element concentrations in tree rings could be detected, although the lime treatment significantly changed the average xylem Mg and Mn concentrations as well as the average Mg/Mn and Ca/Mn ratios of the sapwood. The absence of temporal trends in rings from the last 20 yr implied a significant re‐equilibration of elements through the sapwood. Significant relationships were found between averaged xylem Ca/Mn and Mg/Mn ratios and exchangeable humus Ca, Mg, Mn, Al, Fe, and H+concentration, EA, CECe, and BSe, suggesting that the average xylem Ca/Mn and Mg/Mn ratios are strong indicators of the soil acid–base status.
Growth and Yield Responses of Snap Bean to Mixtures of Carbon Dioxide and Ozone
Authors: Heagle A. S. , Miller J. E. , Burkey K. O. , Eason G. , Pursley W. A.
Published: June 2010

Elevated CO2 concentrations expected in the 21st century can stimulate plant growth and yield, whereas tropospheric O3 suppresses plant growth and yield in many areas of the world. Recent experiments showed that elevated CO2 often protects plants from O3 stress, but this has not been tested for many important crop species including snap bean (Phaseolus vulgaris L.). The objective of this study was to determine if elevated CO2 protects snap bean from O3 stress. An O3–tolerant cultivar (Tenderette) and an O3–sensitive selection (S156) were exposed from shortly after emergence to maturity to mixtures of CO2 and O3 in open‐top field chambers. The two CO2 treatments were ambient and ambient with CO2 added for 24 h d−1 resulting in seasonal 12 h d−1 (0800–2000 h EST) mean concentrations of 366 and 697 μL L−1, respectively. The two O3 treatments were charcoal‐filtered air and nonfiltered air with O3 added for 12 h d−1 to achieve seasonal 12 h d−1 (0800–2000 h EST) mean concentrations of 23 and 72 nL L−1, respectively. Elevated CO2 significantly stimulated growth and pod weight of Tenderette and S156, whereas elevated O3 significantly suppressed growth and pod weight of S156 but not of Tenderette. The suppressive effect of elevated O3 on pod dry weight of S156 was approximately 75% at ambient CO2 and approximately 60% at elevated CO2 (harvests combined). This amount of protection from O3 stress afforded by elevated CO2 was much less than reported for other crop species. Extreme sensitivity to O3 may be the reason elevated CO2 failed to significantly protect S156 from O3 stress.
Evaluation of the Macroalga, Muskgrass, for the Phytoremediation of Selenium‐Contaminated Agricultural Drainage Water by Microcosms
Authors: Lin Z.‐Q. , de Souza M. , Pickering I. J. , Terry N.
Published: June 2010

Previous field studies suggested that the macroalga, muskgrass (Chara canescensDesv. & Lois), plays an important role in the removal of selenium (Se) from agricultural drainage water. This study evaluated the efficiency of Se removal from drainage water by muskgrass‐vegetated wetland microcosms, and determined the extent to which muskgrass removed Se through phytoextraction and biovolatilization. Six flow‐through wetland microcosms were continuously supplied with drainage water containing an average Se concentration of 22 μg L−1over a 24‐d experimental period. The Se mass input and outflow and the rate of Se volatilization were monitored daily for each microcosm. Three microcosms containing muskgrass reduced the daily mass Se input in the inflow drainage water by 72.1%; this compared with a reduction of 50.6% of the mass Se input for three unvegetated control microcosms. Selenium accumulated in muskgrass tissues accounted for 1.9% of the total mass Se input in the microcosm, followed by 0.5% via biological volatilization. The low rates of Se volatilization from selenate‐supplied muskgrass, which were 10‐fold less than from selenite, were probably due to a major rate limitation in the reduction of selenate to organic forms of Se in muskgrass. This conclusion was derived from X‐ray absorption spectroscopy speciation analysis, which showed that muskgrass treated with selenite contained 91% of the total Se in organic forms (selenoethers and diselenides), compared with 47% in muskgrass treated with selenate.
Limnological Assessment of Verkhne Viiskii Reservoir, Russian Federation
Authors: Kennedy Robert H. , Hains John J.
Published: June 2010

Verkhne Viiskii Reservoir (surface area = 6.0 km2; volume = 36.0 hm3), one of two water supply reservoirs for the City of Nizhnii Tagil, is located in a forested watershed (drainage area = 272 km2) in the Ural Mountain region of the Russian Federation. This study, conducted in August 1999, provides a benchmark limnological assessment against which to gauge future change. While currently meeting local water quality requirements for drinking water sources, the reservoir exhibits moderately eutrophic characteristics, including elevated epilimnetic nutrient (total P = 0.048–0.115 mg L−1; total N = 0.421–0.508 mg L−1) and chlorophyll (4–8.4 μg L−1) concentrations, and a high rate of hypolimnetic oxygen depletion (4.07 g m−3 mo−1).
Responses of Red‐Osier Dogwood to Oil Sands Tailings Treated with Gypsum or Alum
Authors: Redfield E. , Croser C. , Zwiazek J. J. , MacKinnon M. D. , Qualizza C.
Published: June 2010

The application of composite or consolidated tailings (CT) technology provides Alberta's oil sands industry with a means of reducing the volume of the fines fraction in extraction tailings and allows for faster reclamation and revegetation of mining sites. This study examined the effects of coagulant aids (gypsum and alum), used in the production of CT, on the ion content, growth, and survival of greenhouse‐grown red‐osier dogwood (Cornus sericea L. subsp. sericea). Seedlings were planted in gypsum‐CT and alum‐CT substrates, and compared with those planted in reclamation material (salvaged peat and till). The seedlings were bottom‐watered with one of the following: (i) Hoagland mineral solution prepared in deionized water (Epstein, 1972); (ii) Hoagland solution in gypsum‐based CT release water; or (iii) Hoagland solution in alum‐based CT release water. Pore water of CT substrates and CT release waters had similar chemical characteristics, including salinity levels. However, plants in CT substrates had higher concentrations of ions (particularly Na and B), reduced growth, and higher mortality than plants in reclamation material and treated with CT waters. The presence of H2S indicated low‐oxygen conditions in the CT substrates, while in the reclamation materials with CT release water treatments, no evidence of sulfides was observed. Low‐oxygen conditions in the CT substrate treatments may have interfered with plant exclusion mechanisms for Na and B. Therefore, substrate properties may modify responses of reclamation plants to pore water chemistry due to the effects on oxygen availability to roots.
Sequestration of Phosphorus by Acid Mine Drainage Floc
Authors: Adler Paul R. , Sibrell Philip L.
Published: June 2010

Solubilization and transport of phosphorus (P) to the water environment is a critical environmental issue. Flocs resulting from neutralizing acid mine drainage (AMD) were tested as a possible low‐cost amendment to reduce the loss of soluble P from agricultural fields and animal wastewater. Flocs were prepared by neutralizing natural and synthetic solutions of AMD with limestone, lime, ammonium hydroxide, and sodium hydroxide. Phosphorus sequestration was tested in three distinct environments: water, soil, and manure storage basins. In water, flocs prepared from AMD adsorbed 10 to 20 g P kg−1 dry floc in equilibrium with 1 mg L−1 soluble P. Similar results were observed for both Fe‐based and Al‐based synthetic flocs. A local soil sample adsorbed about 0.1 g P kg−1, about two orders of magnitude less. The AMD‐derived flocs were mixed with a high‐P soil at 5 to 80 g floc kg−1 soil, followed by water and acid (Mehlich‐1) extractions. All flocs performed similarly. About 70% of the water‐extractable P was sequestered by the floc when applied at a rate of 20 g floc kg−1 soil, whereas plant‐available P only decreased by about 30%. Under anaerobic conditions simulating manure storage basins, all AMD flocs reduced soluble P by greater than 95% at a rate of 0.2 g floc g−1 rainbow trout (Oncorhynchus mykiss) manure. These findings indicate that AMD flocs could be an effective agent for preventing soluble P losses from soil and manure to the water environment, while at the same time decreasing the costs associated with AMD treatment.
Atmospheric Ammonia, Volatile Fatty Acids, and Other Odorants near Beef Feedlots
Authors: McGinn S. M. , Janzen H. H. , Coates T.
Published: June 2010

Intensive livestock operations can release odorous gases from stored or land‐applied manure. We measured concentrations of dust and 14 odor‐causing gases at increasing distances from four feedlots near Lethbridge, southern Alberta, Canada. Concentration was determined from the amount of total dust or gas accumulated in the samplers, and the volume of air sampled. Adjacent the feedlots, the maximum concentration of many volatile fatty acids exceeded reported odor detection thresholds; the maximum ammonia concentration was close to the threshold. Ammonia and butyric acid approached or exceeded their individual odor thresholds as far as 200 m downwind of the feedlots. Highest concentrations were measured adjacent to land where manure was being applied. None of the odorant concentrations exceeded their irritation threshold. There was a positive relationship between ammonia concentration and odor intensity as well as dry deposition. Much of the emitted ammonia was deposited to soil immediately downwind, enough to supply all the nitrogen needed for crop growth. Odorant concentrations declined sharply with distance, though measurable odor occasionally persisted to 1 km from the feedlot, beyond the minimum separation guidelines (Alberta) for a single residential dwelling. The weekly averaged total suspended particulates (>5 μm) were below the Alberta guideline criterion except for one period. Differences among feedlots in odorant plume concentrations were partly related to the stocking density of feedlots, which presumably affects manure moisture and amount of volatiles within the pens.
Effect of Nonylphenol Surfactants on Fungi following the Application of Sewage Sludge on Agricultural Soils
Authors: Kollmann Albert , Brault Agathe , Touton Isabelle , Dubroca Jacqueline , Chaplain Véronique , Mougin Christian
Published: June 2010

The effect of nonylphenol on fungi following the application of contaminated sewage sludge on agricultural soil was studied in laboratory experiments. Nonylphenol bioavailability and adsorption were determined in the soil alone and soil–sludge mixtures. Mixing the soil with sludge made it possible to measure the nonylphenol concentration in the soil solution, which comprised between 6.6 × 10−6 and 3.8 × 10−7 M, according to the sludge. We then examined the dose–response relationship between nonylphenol concentration in the culture medium and both biomass production and germination rate of the spores from several strains of filamentous fungi. When applied in this range of concentration, nonylphenol was without noticeable short‐term effect on these endpoints. Long‐term exposure of fungi to nonylphenol was also assessed. The most intensive effect was a strong stimulation of spore production and germination in Fusarium oxysporum Schlechtendahl. Biomass production by the Fusarium strains also increased. Finally, nonylphenol was shown to induce laccase production in Trametes versicolor We conclude that the potential of nonylphenol to adversely affect several soil fungi remains low.
Effects of Oxide Coating and Selected Cations on Nitrate Reduction by Iron Metal
Authors: Huang Yong H. , Zhang Tian C. , Shea Patrick J. , Comfort Steve D.
Published: June 2010

Under anoxic conditions, zerovalent iron (Fe0) reduces nitrate to ammonium and magnetite (Fe3O4) is produced at near‐neutral pH. Nitrate removal was most rapid at low pH (2–4); however, the formation of a black oxide film at pH 5 to 8 temporarily halted or slowed the reaction unless the system was augmented with Fe2+, Cu2+, or Al3+ Bathing the corroding Fe0 in a Fe2+ solution greatly enhanced nitrate reduction at near‐neutral pH and coincided with the formation of a black precipitate. X‐ray diffractometry and scanning electron microscopy confirmed that both the black precipitate and black oxide coating on the iron surface were magnetite. In this system, ferrous iron was determined to be a partial contributor to nitrate removal, but nitrate reduction was not observed in the absence of Fe0 Nitrate removal was also enhanced by augmenting the Fe0–H2O system with Fe3+, Cu2+, or Al3+ but not Ca2+, Mg2+, or Zn2+ Our research indicates that a magnetite coating is not a hindrance to nitrate reduction by Fe0, provided sufficient aqueous Fe2+ is present in the system.
Bermudagrass Management in the Southern Piedmont USA
Authors: Franzluebbers Alan J. , Stuedemann John A.
Published: June 2010

Fate of applied N in forage‐based agricultural systems is important to long‐term production and environmental impacts. We evaluated the factorial combination of N fertilization targeted to supply 20 g N m−2 yr−1 and harvest strategies on soil‐profile inorganic N during the first 5 yr of ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] management. Harvest strategy had much larger effects than fertilization strategy, most notably that soil‐profile inorganic N was lower when hayed than under other systems. In the upper rooting zone (0‐ to 0.3‐m depth), soil inorganic N (initially at 3.1 g m−2) remained unchanged during the 5 yr under unharvested and low and high grazing pressures (0.00 ± 0.08 g m−2 yr−1), but declined with haying (−0.25 g m−2 yr−1). In the lower rooting zone (0.3‐ to 0.9‐m depth), soil inorganic N (initially at 2.9 g m−2) accumulated with unharvested and low and high grazing pressure (0.64 ± 0.20 g m−2 yr−1), but remained unchanged with haying (−0.06 g m−2 yr−1). Below the rooting zone (0.9‐ to 1.5‐m depth), soil inorganic N (initially at 5.8 g m−2) increased with unharvested and high grazing pressure (0.34 ± 0.03 g m−2 yr−1), was unchanged with low grazing pressure (−0.10 g m−2 yr−1), and declined with haying (−0.50 g m−2 yr−1). Applied N appears to have been efficiently utilized by forage with subsequent sequestration into soil organic matter and little movement of inorganic N below the rooting zone (<2% of applied N), irrespective of inorganic or organic fertilization strategy designed to supply sufficient N for high animal production from grazing.
Aging Effects on the Sorption–Desorption Characteristics of Anthropogenic Organic Compounds in Soil
Authors: Sharer Michael , Park Jeong‐Hun , Voice Thomas C. , Boyd Stephen A.
Published: June 2010

Field studies have demonstrated that prolonged pesticide–soil contact times (aging) may lead to unexpected persistence of these compounds in the environment. Although this phenomenon is well documented in the field, there have been very few controlled laboratory studies that have tested the effects of long‐term aging and the role of differing sorbates on contaminant sorption–desorption behavior and fate in soils. This study examines the sorption–desorption behavior of chlorobenzene, ethylene dibromide (1,2‐dibromomethane), atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine), and 2,4‐D (2,4‐dichlorophenoxyacetic acid) on one soil type after 1 d, 30 d, and 14 mo of aging. Sorption isotherms were evaluated after each aging period to observe changes in the uptake of each compound by soil. Desorption kinetic data were generated after each aging period to observe changes in release from soil, and desorption parameters were evaluated using a three‐site desorption model that includes equilibrium, nonequilibrium, and nondesorption sites. The data indicate no statistically significant increase in sorption for ethylene dibromide or chlorobenzene from 1 to 30 d, although sorption of 2,4‐D increased slightly, and sorption of atrazine decreased slightly. Statistically significant increases in linear sorption coefficients (Kd), from 1 d to 14 mo of aging, were apparent for ethylene dibromide and 2,4‐D. The Kd values for chlorobenzene, measured after 1 d, 30 d, and 14 mo of aging, were statistically indistinguishable. Aging affected the distribution of chemicals within sorption sites. With aging, the desorbable fraction decreased and the nondesorbable fraction, which was apparent after only 1 d of pesticide–soil contact, increased for all chemicals studied.
Using Nonequilibrium Thin‐Disc and Batch Equilibrium Techniques to Evaluate Herbicide Sorption
Authors: Smith M. Cade , Shaw David R. , Massey Joseph H. , Boyette Michele , Kingery William
Published: June 2010

Nonequilibrium disc‐flow techniques may better reproduce dynamic soil–pesticide interactions than traditional batch sorption studies. Batch kinetic and equilibrium experiments and dual‐label thin‐disc flow experiments were conducted with atrazine (6‐chloro‐N‐ethyl‐N′‐isopropyl‐1,3,5‐triazine‐2,4‐diamine) and imazaquin [2‐(4,5‐dihydro‐4‐methyl‐4‐(1‐methylethyl)‐5‐oxo‐1H‐imidazol‐2‐yl)‐3‐quinolinecarboxylic acid] using a Demopolis silt loam (loamy‐skeletal, carbonatic, thermic, shallow Typic Udorthent; 8% clay, 62 g kg−1 organic matter, 7.6 pH). Batch kinetic studies with both herbicides revealed an almost instantaneous rapid phase and a much slower gradual phase. The rapid phase was complete after 5 min and equilibrium was reached at 24 h. The rapid phase accounted for 74% and 12 to 30% of the total amounts adsorbed for atrazine and imazaquin, respectively. The sorption of both the rapid and 24‐h isotherms for each herbicide best fit the Freundlich equation. The rapid and 24‐h Kf values of atrazine were 1.38 and 2.41, respectively, and the N value of both phases was approximately 0.93. For imazaquin, the rapid and 24‐h Kf values were 0.056 and 0.35, respectively, and the N value for the rapid phase of imazaquin was 0.71, compared with 0.86 for the 24‐h isotherm. In the dual‐label thin‐disc flow experiments, the average partition coefficient for atrazine at the peak soil concentration point was 1.54. This value closely agreed with the observed rapid‐phase Kf value of 1.38. In contrast, the thin‐disc flow experiments failed to detect any imazaquin retention. The thin‐disc flow method can allow for a greater resolution of rapid sorption kinetics, which is impractical with batch studies. Along with dynamic partitioning data, the thin‐disc flow method may provide kinetics data that may better complement environmental models than coefficients generated with batch techniques.
Estimating Nitrate Leaching with a Transfer Function Model Incorporating Net Mineralization and Uptake of Nitrogen
Authors: Ren Li , Ma Junhua , Zhang Renduo
Published: June 2010

Because of the complex interaction of chemical and biological processes of nitrogen (N) in soils, it is difficult to estimate the leaching of nitrate with various N transformations in porous media. In this study, a transfer function model was developed to simulate the outflow concentration of nitrate in soils during the growth of winter wheat (Triticum aestivum L.), taking into account the main N transformations using source and sink terms. The source and sink terms were treated as inputs to the solute transport volume and incorporated into the transfer function model to characterize their effects on nitrate concentration in the outflow. A field experiment was conducted in three nonweighing lysimeters for 181 d. Nitrate concentrations were measured along the 2‐m soil profile of each lysimeter at different times. Comparison between the experimental data and simulated results with the transfer function showed that the model provided reasonable prediction of the nitrate leaching process as well as the total amount leached. Results also indicated that considering the N transformations in the transfer function significantly increased the estimation accuracy. The relative errors of total amount leached were <7% with the N transformations included, but up to 17% without including the transformation processes.
Efficacy of Alum and Coal Combustion By‐Products in Stabilizing Manure Phosphorus
Authors: Dou Z. , Zhang G. Y. , Stout W. L. , Toth J. D. , Ferguson J. D.
Published: June 2010

Animal manures contain large amounts of soluble phosphorus (P), which is prone to runoff losses when manure is surface‐applied. Here we report the efficacy of alum and three coal combustion by‐products in reducing P solubility when added to dairy, swine, or broiler litter manures in a laboratory incubation study. Compared with unamended controls, alum effectively reduced readily soluble P, determined in water extracts of moist manure samples with 1 h of shaking, for all three manures. The reduction ranged from 80 to 99% at treatment rates of 100 to 250 g alum kg−1manure dry matter. The fluidized bed combustion fly ash (FBC) reduced readily soluble P by 50 to 60% at a rate of 400 g kg−1for all three manures. Flue gas desulfurization by‐product (FGD) reduced readily soluble P by nearly 80% when added to swine manure and broiler litter at 150 and 250 g kg−1Another by‐product, anthracite refuse fly ash (ANT), was ineffective for all three manures. In all cases, reduction in readily soluble P is primarily associated with inorganic phosphorus (Pi) with little change in organic phosphorus (Po). Sequential extraction results indicate that the by‐product treatments shifted manure P from H2O‐P into a less vulnerable fraction, NaHCO3−P, while the alum treatment shifted the P into even more stable forms, mostly NaOH‐P. Such shifts in P fractions would have little influence on P availability for crops over the long term but would retard and reduce potential losses of P following manure applications.
Fate of Coliform Bacteria in Composted Beef Cattle Feedlot Manure
Authors: Larney Francis J. , Yanke L. Jay , Miller James J. , McAllister Tim A.
Published: June 2010

The link between livestock production, manure management, and human health has received much public attention in recent years. Composting is often promoted as a means of sanitizing manure to ensure that pathogenic bacteria are not spread to a wider environment during land application. In a two‐year study (1998 and 1999) in southern Alberta, we examined the fate of coliform bacteria during windrow composting of cattle (Bos taurus) manure from feedlot pens bedded with cereal straw or wood chips. Numbers of total coliforms (TC) and Escherichia coli declined as the composting period progressed. In 1998, TC levels (mean of both bedding types) were log10 7.86 cells g−1 dry wt. for raw manure on Day 0, log10 3.38 cells g−1 by Day 7, and log10 1.69 cells g−1 by Day 14. More than 99.9% of TC and E. coli was eliminated in the first 7 d when average windrow temperatures ranged from 33.5 to 41.5°C. The type of bedding did not influence the numbers of TC or E. coli Dessication probably played a minor role in coliform elimination, since water loss was low (<0.07 kg kg−1) in the first 7 d of composting. However, total aerobic heterotroph populations remained high (>7.0 log10 CFU g−1 dry wt., where CFU is colony forming units) throughout the composting period, possibly causing an antagonistic effect. Land application of compost, with its nondetectable levels of E. coli compared with raw manure, should minimize environmental risk in areas of intensive livestock production.
Advanced Solid‐State Carbon‐13 Nuclear Magnetic Resonance Spectroscopic Studies of Sewage Sludge Organic Matter
Authors: Smernik Ronald J. , Oliver Ian W. , Merrington Graham
Published: June 2010

Two novel solid‐state 13C nuclear magnetic resonance (NMR) spectroscopic techniques, PSRE (proton spin relaxation editing) and RESTORE [Restoration of Spectra via TCH and T1ρH (T One Rho H) Editing], were used to provide detailed chemical characterization of the organic matter from six Australian sewage sludges. These methods were used to probe the submicrometer heterogeneity of sludge organic matter, and identify and quantify spatially distinct components. Analysis of the T1H relaxation behavior of the sludges indicated that each sludge contained two types of organic domains. Carbon‐13 PSRE NMR subspectra were generated to determine the chemical nature of these domains. The rapidly relaxing component of each sludge was rich in protein and alkyl carbon, and was identified as dead bacterial material. The slowly relaxing component of each sludge was rich in carbohydrate and lignin structures, and was identified as partly degraded plant material. The bacterial domains were shown, using the RESTORE technique, to also have characteristically rapid T1ρH relaxation rates. This rapid T1ρH relaxation was identified as the main cause of underrepresentation of these domains in standard 13C cross polarization (CP) NMR spectra of sludges. The heterogeneous nature of sewage sludge organic matter has implications for land application of sewage sludge, since the two components are likely to have different capacities for sorbing organic and inorganic toxicants present in sewage sludge, and will decompose at different rates.