bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphorus Retention Mechanisms of a Water Treatment Residual
Authors: Ippolito J. A. , Barbarick K. A. , Heil D. M. , Chandler J. P. , Redente E. F.
Published: June 2010

Water treatment residuals (WTRs) are a by‐product of municipal drinking water treatment plants and can have the capacity to adsorb tremendous amounts of P. Understanding the WTR phosphorus adsorption process is important for discerning the mechanism and tenacity of P retention. We studied P adsorbing mechanism(s) of an aluminum‐based [Al2(SO4)3·14H2O] WTR from Englewood, CO. In a laboratory study, we shook mixtures of P‐loaded WTR for 1 to 211 d followed by solution pH analysis, and solution Ca, Al, and P analysis via inductively coupled plasma atomic emission spectroscopy. After shaking periods, we also examined the solids fraction by X‐ray diffraction (XRD) and electron microprobe analysis using wavelength dispersive spectroscopy (EMPA–WDS). The shaking results indicated an increase in pH from 7.2 to 8.2, an increase in desorbed Ca and Al concentrations, and a decrease in desorbed P concentration. The pH and desorbed Ca concentration increases suggested that CaCO3controlled Ca solubility. Increased desorbed Al concentration may have been due to Al OH−4formation. Decreased P content, in conjunction with the pH increase, was consistent with calcium phosphate formation or precipitation. The system appeared to be undersaturated with respect to dicalcium phosphate (DCP; CaHPO4) and supersaturated with respect to octacalcium phosphate [OCP; Ca4H(PO4)3·2.5H2O]. The Ca and Al increases, as well as OCP formation, were supported by MINTEQA2 modeling. The XRD and EMPA–WDS results for all shaking times, however, suggested surface P chemisorption as an amorphous Al–P mineral phase.
Recycling Soil Nitrate Nitrogen by Amending Agricultural Lands with Oily Food Waste
Authors: Rashid M. T. , Voroney R. P.
Published: June 2010

With current agricultural practices the amounts of fertilizer N applied are frequently more than the amounts removed by the crop. Excessive N application may result in short‐term accumulation of nitrate nitrogen (NO3–N) in soil, which can easily be leached from the root zone and into the ground water. A management practice suggested for conserving accumulated NO3–N is the application of oily food waste (FOG; fat + oil + greases) to agricultural soils. A two‐year field study (1995–1996 and 1996–1997) was conducted at Elora Research Center (43°38′ N, 80° W; 346 m above mean sea level), University of Guelph, Ontario, Canada to determine the effect of FOG application in fall and spring on soil NO3–N contents and apparent N immobilization–mineralization of soil N in the 0‐ to 60‐cm soil layer. The experiment was planned under a randomized complete block design with four replications. An unamended control and a reference treatment [winter wheat (Triticum aestivumL.) cover crop] were included in the experiment to compare the effects of fall and spring treatment of oily food waste on soil NO3–N contents and apparent N immobilization–mineralization. Oily food waste application at 10 Mg ha−1in the fall decreased soil NO3–N by immobilization and conserved 47 to 56 kg NO3–N ha−1, which would otherwise be subject to leaching. Nitrogen immobilized due to FOG application in the fall was subsequently remineralized by the time of fertilizer N sidedress, whereas no net mineralization was observed in spring‐amended plots at the same time.
Methane Emissions of Rice Increased by Elevated Carbon Dioxide and Temperature
Authors: Allen Leon H. , Albrecht Stephan L. , Colón‐Guasp Wilfredo , Covell Stephen A. , Baker Jeffrey T. , Pan Deyun , Boote Kenneth J.
Published: June 2010

Methane (CH4) effluxes by paddy‐culture rice (Oryza sativa L.) contribute about 16% of the total anthropogenic emissions. Since radiative forcing of CH4 at current atmospheric concentrations is 21 times greater on a per mole basis than that of carbon dioxide (CO2), it is imperative that the impact of global change on rice CH4 emissions be evaluated. Rice (cv. IR72) was planted in sunlit, closed‐circulation, controlled‐environment chambers in which CH4 efflux densities were measured daily. The CO2 concentration was maintained at either 330 or 660 μmol mol−1 Air temperatures were controlled to daily maxima and minima of 32/23, 35/26, and 38/29°C at each CO2 treatment. Emissions of CH4 each day were determined during a 4‐h period after venting and resealing the chambers at 0800 h. Diurnal CH4 effluxes on 77, 98, and 119 d after planting (DAP) were obtained similarly at 4‐h intervals. Emissions over four‐plant hills and over flooded bare soil were measured at 53, 63, and 100 DAP. Emissions were negligible before 40 DAP. Thereafter, emissions were observed first in high‐CO2, high‐temperature treatments and reached a sustained maximum efflux density of about 7 mg m−2 h−1 (0.17 g m−2 d−1) near the end of the growing season. Total seasonal CH4 emission was fourfold greater for high‐CO2, high‐temperature treatments than for the low‐CO2, low‐temperature treatment, probably due to more root sloughing or exudates, since about sixfold more acetate was found in the soil at 71 DAP. Both rising CO2 and increasing temperatures could lead to a positive feedback on global warming by increasing the emissions of CH4 from rice.
Modeling Flow and Nitrate Fate at Catchment Scale in Brittany (France)
Authors: Conan Céline , Bouraoui Fayçal , Turpin Nadine , de Marsily Ghislain , Bidoglio Giovanni
Published: June 2010

In the intensive pig‐farming (Sus scrofa) area of Brittany (western France), many surface and subsurface water resources are contaminated by nitrate (NO3) with concentrations that chronically exceed the European Community 50 mg L−1 drinking standard. To ensure sustainable water supply, the fate of NO3 must be considered in both surface water and ground water. The fate of N was investigated in a Britain catchment, the Coët‐Dan watershed, with an integrated management tool: the hydrological SWAT model coupled with the ground water model MODFLOW, and its companion contaminant and solute transport model MT3DMS. The model was validated with respect to water quantity during a 6‐yr period and for the NO3 concentration during a 44‐mo period, at two gauging stations in the catchment. The coupled models reproduced accurately the measurements. At the basin outlet, the Nash‐Sutcliffe coefficients were 0.88 for monthly flow for the entire period and 0.87 for monthly N load. Alternative scenarios were simulated and showed potential benefits of decreasing manure application from 210 to 170 kg N ha−1 as required by the European Commission Nitrates Directive.
Copper, Zinc, and Arsenic in Soil Surrounding Douglas‐Fir Poles Treated with Ammoniacal Copper Zinc Arsenate (ACZA)
Authors: Morrell J. J. , Keefe Donn , Baileys Randall T.
Published: June 2010

The levels of copper, zinc, and arsenic in soil surrounding Douglas‐fir [Pseudotsuga menziesii (Mirb.) Franco] utility poles treated with ammoniacal copper zinc arsenate (ACZA) were investigated at sites in Florida, Virginia, and New York. Copper levels were elevated near the poles and declined with both horizontal distance away from the pole and depth beneath the soil surface. Zinc levels were also elevated next to the poles, but the levels declined more slowly than did those of copper. Arsenic levels were elevated in soil immediately next to the poles but declined to near background levels farther away. The results indicate that metals can leach from ACZA‐treated poles, but do not migrate far in the soil, and thus the levels decline sharply with distance from the poles.
Long‐Term Effects of Nitrogen Fertilizer Use on Ground Water Nitrate in Two Small Watersheds
Authors: Tomer M. D. , Burkart M. R.
Published: June 2010

Changes in agricultural management can minimize NO3–N leaching, but then the time needed to improve ground water quality is uncertain. A study was conducted in two first‐order watersheds (30 and 34 ha) in Iowa's Loess Hills. Both were managed in continuous corn (Zea mays L.) from 1964 through 1995 with similar N fertilizer applications (average 178 kg ha−1 yr−1), except one received applications averaging 446 kg N ha−1 yr−1 between 1969 and 1974. This study determined if NO3–N from these large applications could persist in ground water and baseflow, and affect comparison between new crop rotations implemented in 1996. Piezometer nests were installed and deep cores collected in 1996, then ground water levels and NO3–N concentrations were monitored. Tritium and stable isotopes (2H, 18O) were determined on 33 water samples in 2001. Baseflow from the heavily N‐fertilized watershed had larger average NO3–N concentrations, by 8 mg L−1 Time‐of‐travel calculations and tritium data showed ground water resides in these watersheds for decades. “Bomb‐peak” precipitation (1963–1980) most influenced tritium concentrations near lower slope positions, while deep ground water was dominantly pre‐1953 precipitation. Near the stream, greater recharge and mixed‐age ground water was suggested by stable isotope and tritium data, respectively. Using sediment‐core data collected from the deep unsaturated zone between 1972 and 1996, the increasing depth of a NO3–N pulse was related to cumulative baseflow (r2 = 0.98), suggesting slow downward movement of NO3–N since the first experiment. Management changes implemented in 1996 will take years to fully influence ground water NO3–N. Determining ground water quality responses to new agricultural practices may take decades in some watersheds.
Behavior of 14C‐Atrazine in Argentinean Topsoils under Different Cropping Managements
Authors: Hang S. , Barriuso E. , Houot S.
Published: June 2010

Atrazine (6‐chloro‐N2–ethyl‐N4–isopropyl‐1,3,5‐triazine‐2,4‐diamine) behavior was studied in four surface soils during incubations in laboratory conditions. Soils were chosen in relation to their cropping management (tillage and no tillage) and crop rotation system (continuous soybean [Glycine max (L.) Merr.] and maize (Zea mays L.)–soybean rotation). A natural soil under brushwood was sampled as a reference. Atrazine use in field conditions was associated with maize cropping, thus only one soil received atrazine every other year. Atrazine behavior was characterized through the balance of 14C‐U‐ring atrazine radioactivity among the mineralized fraction, the extractable fraction, and the nonextractable bound residues. Soil organic matter capacity to form bound residues was characterized using soil size fractionation. Accelerated atrazine mineralization was only observed in the soil receiving atrazine in field conditions. Atrazine application every other year was enough to develop a microflora adapted to triazine ring mineralization. Bound residue formation was rapid and increased with soil organic matter content. The coarsest soil size fractions (2000–200 and 200–50 μm) containing the nonhumified organic matter presented the highest capacity to form bound residues. No effect of tillage system was observed, probably because of the uniform sampling depth at 20 cm, hiding the stratification pattern of soil organic matter in nontilled soils.
Biogeochemistry of Fluoride in a Plant–Solution System
Authors: Mackowiak C. L. , Grossl P. R. , Bugbee B. G.
Published: June 2010

Fluoride (F−) pollutants can harm plants and the animals feeding on them. However, it is largely unknown how complexing and chelating agents affect F bioavailability. Two studies were conducted that measured F− bioavailability and uptake by rice (Oryza sativa L.). In the first study, rice was grown in solution culture (pH 5.0) with 0, 2, or 4 mM F− as KF to compare the interaction of F− with humic acid (HA) and with a conventional chelating agent, N‐hydroxyethylenthylenediaminetriacetic acid (HEDTA). In the second study, F was supplied at 0, 0.5, 1.0, and 2.0 mM KF with an additional 2 mM F− treatment containing solution Ca at 2× (2 mM Ca) the level used in the first study, to test the effect added Ca had on F− availability and uptake. Total biomass was greatest with HEDTA and F− < 1 mM Leaf and stem F concentrations increased exponentially as solution F− increased linearly, with nearly no F partitioning into the seed. Results suggest that F was taken up as HF0 while F− uptake was likely restricted. Additionally, F− competed with HA for Ca, thus preventing the formation of Ca–HA flocculents. The addition of soluble Ca resulted in the precipitation of CaF2 solids on the root surface, as determined by tissue analysis and energy dispersive X‐ray spectroscopy.
Aluminum Effect on Dissolution and Precipitation under Hyperalkaline Conditions
Authors: Qafoku Nikolla P. , Ainsworth Calvin C. , Szecsody James E. , Bish David L. , Young James S. , McCready David E. , Qafoku Odeta S.
Published: June 2010

The high‐level radioactive, Al‐rich, concentrated alkaline and saline waste fluids stored in underground tanks have accidentally leaked into the vadose zone at the Hanford Site in Washington State. In addition to dissolution, precipitation is likely to occur when these waste fluids contact the sediments. The objective of this study was to investigate the solid phase transformations caused by dissolution and precipitation in the sediments treated with solutions similar to the waste fluids. Batch experiments at 323 K were conducted in metal‐ and glass‐free systems under CO2 and O2 free conditions. Results from X‐ray diffraction (XRD), quantitative X‐ray diffraction (QXRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and energy dispersive X‐ray fluorescence spectroscopy (EDXRF) indicated that significant solid phase transformations occurred in the sediments contacted with Al‐rich, hyperalkaline, and saline solutions. The XRD and QXRD analyses confirmed that smectite and most likely biotite underwent dissolution. The SEM and the qualitative EDS analyses confirmed the formation of alumino‐silicates in the groups of cancrinite and probably sodalite. The morphology of the alumino‐silicates secondary phases changed in response to changes in the Si/Al aqueous molar ratio. The transformations in the sediments triggered by dissolution (weathering of soil minerals) and precipitation (formation of secondary phases with high specific surface area and probably high sorption capacities) may play a significant role in the immobilization and ultimate fate of radionuclides and contaminants such as Cs, Sr, and U in the Hanford vadose zone.
Accumulation, Release, and Solubility of Arsenic, Molybdenum, and Vanadium in Wetland Sediments
Authors: Fox Patricia M. , Doner Harvey E.
Published: June 2010

This study was undertaken to determine the fate of As, Mo, and V (trace elements, TEs) in the sediments of a constructed wetland in use for the remediation of potentially toxic trace element–contaminated agricultural drainwater. After three years of wetland operation, sediment cores were collected to determine changes in TE concentrations as a function of depth and the effects of varying water column depth. All TE concentrations were highest in the top 2 to 4 cm and decreased with depth. Molybdenum accumulated in the wetland sediments, up to levels of 32.5 ± 4.6, 30.2 ± 8.9, and 59.3 ± 26.1 mg kg−1 in the top 1 cm of sediment at water depths of 15, 30, and 60 cm, respectively. In the top 2 cm of sediment, As accumulated (28.2 ± 3.0 mg kg−1) only at the 60‐cm water depth. Below 2 cm, as much as 10 mg kg−1 of As was lost from the sediment at all water depths. In most cases, V concentrations decreased in the sediment. In this wetland system, the lowest redox potentials were found near the sediment surface and increased with depth. Thus, in general As, Mo, and V concentrations in the sediment were highest under more reducing conditions and lowest under more oxidizing conditions. Most of the accumulated Mo (73%) became water soluble on drying of samples. This has important implications for systems undergoing changes in redox status; for instance, if these wetland sediments are dried, potentially large amounts of Mo may be solubilized.
Impact of Genetically Modified Crops on Soil‐ and Plant‐Associated Microbial Communities
Authors: Dunfield Kari E. , Germida James J.
Published: June 2010

Transgenic or genetically modified plants possess novel genes that impart beneficial characteristics such as herbicide resistance. One of the least understood areas in the environmental risk assessment of genetically modified crops is their impact on soil‐ and plant‐associated microbial communities. The potential for interaction between transgenic plants and plant residues and the soil microbial community is not well understood. The recognition that these interactions could change microbial biodiversity and affect ecosystem functioning has initiated a limited number of studies in the area. At this time, studies have shown the possibility that transgenes can be transferred to native soil microorganisms through horizontal gene transfer, although there is not evidence of this occurring in the soil. Furthermore, novel proteins have been shown to be released from transgenic plants into the soil ecosystem, and their presence can influence the biodiversity of the microbial community by selectively stimulating the growth of organisms that can use them. Microbial diversity can be altered when associated with transgenic plants; however, these effects are both variable and transient. Soil‐ and plant‐associated microbial communities are influenced not only by plant species and transgene insertion but also by environmental factors such as field site and sampling date. Minor alterations in the diversity of the microbial community could affect soil health and ecosystem functioning, and therefore, the impact that plant variety may have on the dynamics of the rhizosphere microbial populations and in turn plant growth and health and ecosystem sustainability, requires further study.
Assessment of Crown Condition in Eucalypt Vegetation by Remotely Sensed Optical Indices
Authors: Coops Nicholas C. , Stone Christine , Culvenor Darius S. , Chisholm Laurie
Published: June 2010

Leaf and crown damage and discoloration characteristics are important variables when defining the health of eucalypt tree species and have been used as key indicators of environmental quality. These indicators can vary significantly over a few hectares, especially in mixed‐species forests, making field‐based environmental surveillance of crown condition an extremely expensive and logistically impractical task. Reflectance in narrow spectral wavelengths obtained from a field‐based spectroradiometer and a Compact Airborne Spectrographic Imager 2 (CASI‐2) were collected over eucalypt vegetation of varying condition in southeastern Australia and compared with leaf‐ and crown‐based attributes including percent red foliage discoloration, percent leaf damage, and crown density and crown foliage condition. Of the leaf attributes sampled, percent leaf damage was well correlated with a red‐green spectral index (r = 0.68, p < 0.01), and percent red discoloration was well correlated with the slope of the red‐edge for selected species (r = 0.89, p < 0.001). Within‐tree crown density was well correlated with the slope of the red‐edge (r = 0.77, p < 0.001) and a previously published index of plant stress with crown foliage condition (r = 0.88, p < 0.01) for selected species. Despite evidence of strong interspecific variability, a set of narrow spectral wavelengths in the visible and near‐infrared regions of the spectrum have been identified that will be useful in the development of forest ecosystem environmental quality indicators.
Reducing Phosphorus Runoff from Swine Manure with Dietary Phytase and Aluminum Chloride
Authors: Smith D. R. , Moore P. A. , Maxwell C. V. , Haggard B. E. , Daniel T. C.
Published: June 2010

Phosphorus (P) runoff from fields fertilized with swine (Sus scrofa) manure has been implicated in eutrophication. Dietary modification and manure amendments have been identified as best management practices to reduce P runoff from manure. This study was conducted to compare the effects of dietary modification and aluminum chloride (AlCl3) manure amendments on reducing P in swine manure and runoff. Twenty‐four pens of nursery swine were fed either a normal diet or a phytase‐amended diet. Each pen was connected to a separate manure pit, which was treated with AlCl3 to give final concentrations in the liquid manure of 0 (control), 0.25, 0.50, or 0.75% (v/v). Manure was collected and applied to plots cropped with tall fescue (Festuca arundinacea Schreb.), and simulated rainfall was applied at 50 mm h−1, sufficient to generate a minimum of 30 min of continuous runoff. Samples of manure and runoff were analyzed for P and Al concentrations. Phytase reduced manure soluble reactive phosphorus (SRP) by 17%, while AlCl3 reduced manure SRP by as much as 73% compared with normal manure. Phosphorus runoff was reduced from 5.7 to 2.6 mg P L−1 (a 53% reduction) using AlCl3 The mean SRP concentration in runoff from phytase diets without AlCl3 was 7.1 mg P L−1 during the first rainfall simulation. When phytase and AlCl3 were used together, both manure SRP and P runoff were reduced more than if either treatment were used without the benefit of the other. Use of AlCl3 did not increase soluble Al in manure or Al lost in runoff. Results from this study indicate that producers should use dietary manipulation with phytase and AlCl3 manure amendments to reduce potential P losses from fields fertilized with swine manure.
Hybrid Poplar and Forest Soil Response to Municipal and Industrial By‐Products: A Greenhouse Study
Authors: Cavaleri Molly A. , Gilmore Daniel W. , Mozaffari Morteza , Rosen Carl J. , Halbach Thomas R.
Published: June 2010

Little research has been conducted in the Lake States (Minnesota, Wisconsin, and Michigan) to evaluate the effects of municipal and industrial by‐product applications on the early growth of short rotation woody crops such as hybrid poplar. Anticipated shortages of harvestable‐age aspen in the next decade can be alleviated and rural development can be enhanced through the application of by‐products to forest soils. This study was conducted to evaluate the effects of inorganic fertilizer, boiler ash, biosolids, and the co‐application of ash and biosolids application on tree growth and soil properties by measuring hybrid poplar clone NM‐6 (Populus nigra L. × P. maximowiczii A. Henry) yield, nutrient uptake, and select post‐harvest soil properties after 15 wk of greenhouse growth. Treatments included a control of no amendment; agricultural lime; inorganic N, P, and K; three types of boiler ash; biosolids application rates equivalent to 70, 140, 210, and 280 kg available N ha−1; and boiler ash co‐applied with biosolids. All of the by‐products treatments showed biomass production that was equal to or greater than inorganic fertilizer and lime treatments. A trend of increased biomass with increasing rates of biosolids was observed. Soil P concentration increased with increasing rates of biosolids application. None of the by‐products treatments resulted in plant tissue metal concentrations greater than metal concentrations of plant tissue amended with inorganic amendments. Biosolids, boiler ash, and the co‐application of biosolids and boiler ash together on forest soils were as beneficial to plant growth as inorganic fertilizers.
Laboratory Characterization of Phosphorus in Fresh and Oven‐Dried Organic Amendments
Authors: Ajiboye B. , Akinremi O. O. , Racz G. J.
Published: June 2010

This study was performed to determine the forms of P and to examine the influence of oven‐drying on P forms in different organic amendments. Samples of biosolids, beef and dairy cattle manures, and hog manures from sow and nursery barns were used in this study. Both fresh and oven‐dried amendments were analyzed for inorganic (Pi), organic (Po), and total phosphorus using a modified Hedley fractionation technique. Water extracted about 10% of total biosolids P and 30 to 40% of total hog and cattle manure P. The amount of P extracted by NaHCO3 ranged from 21 to 32% of total P in all organic amendments except in the dairy cattle manure with 45% of total P. The labile P fraction (sum of H2O‐ and NaHCO3–extractable P) was 24% of biosolids P, 60% of hog manure P, and 70% of dairy cattle manure P. The residual P was about 10% in biosolids and cattle manures and 5 to 8% in hog manures. Oven‐drying caused a transformation in forms of P in the organic amendments. In hog manures, H2O‐extractable Po was transformed to Pi, while in the dairy manure NaHCO3–extractable P was converted to H2O‐extractable Pi with oven‐drying. Therefore, caution should be exercised in using oven‐drying for studies that evaluate forms of P in organic amendments. Overall, these results indicate that biosolids P may be less susceptible to loss by water when added to agricultural land.
An Environmental Threshold for Degree of Phosphorus Saturation in Sandy Soils
Authors: Nair V. D. , Portier K. M. , Graetz D. A. , Walker M. L.
Published: June 2010

There is critical need for a practical indicator to assess the potential for phosphorus (P) movement from a given site to surface waters, either via surface runoff or subsurface drainage. The degree of phosphorus saturation (DPS), which relates a measure of P already adsorbed by a soil to its P adsorption capacity, could be a good indicator of that soil's P release capability. Our primary objective was to find a suitable analytical protocol for determining DPS and to examine the possibility of defining a threshold DPS value for Florida's sandy soils. Four farmer‐owned dairy sprayfields were selected within the Suwannee River basin and soil profiles were randomly obtained from each site, as well as from adjacent unimpacted sites. The soil samples were divided either by horizon or depth, and DPS was determined for each soil sample using ammonium‐oxalate (DPSOx), Mehlich‐1 (DPSM1), and Mehlich‐3 (DPSM3) extracts. All methods of DPS calculations were linearly related to one another (r2 > 0.94). Relationships between water‐soluble P and DPS indicate that the respective change points are: DPSOx = 20%, DPSM1 = 20%, and DPSM3 = 16%. These relationships include samples from Ap, E, and Bt horizons, and various combinations thereof, suggesting that DPS values can be used as predictors of P loss from a soil irrespective of the depth of the soil within a profile. Taking into consideration the change points, confidence intervals, agronomic soil test values, and DPS values from other studies, we suggest replacing Mehlich‐1 P values in the Florida P Index with the three DPS categories (DPSM1 = <30, 30–60, and >60%) to assign different P loss ratings in the P Index.
Variation in and Constraints upon the Decomposition of Woolscour Sludge
Authors: Kroening S. J. , Greenfield L. G. , Williamson W. M.
Published: June 2010

The woolscouring (wool washing) industry has traditionally been viewed as highly polluting and, consequently, effluent treatment systems have been sought. The first stage in the current treatment system for woolscour wastewater, a chemical flocculation process (Sirolan CF), creates a sludge composed of soil and wool grease. We investigated the chemical and biological characteristics of this sludge. The sludge was found to be highly variable on a day to day basis in terms of its chemical composition and biodegradability; 0.8 to 27.8% of sludge total nitrogen was mineralized over 30 d at 37°C. The grease component of sludge (14–40% on a dry weight basis) may retard the decomposition of the sludge but the polyacrylamide flocculant used in its production and its pesticide content had no effect on the rate of decomposition. Our results suggest that variability in substrate quality may translate into variability in treatment performance and have important implications for the biological treatment of industrial wastes, including composting.
An Assessment of Nitrogen‐Based Manure Application Rates on 39 U.S. Swine Operations
Authors: Lory John A. , Massey Raymond E. , Zulovich Joseph M. , Hoehne John A. , Schmidt Amy M. , Carlson Marcia S. , Fulhage Charles D.
Published: June 2010

Water quality concerns and revised regulations are changing how confined animal feeding operations manage manure. Devising acceptable and feasible changes in manure practices requires a full understanding of the forces shaping current manure management decisions. Previous theoretical models have shown that a wide range of factors influence the lowest cost solution for manure management. We used a mechanistic model to characterize the manure management practices on 39 swine operations (20 unagitated lagoon and 19 slurry operations) in five states (Iowa, Missouri, North Carolina, Oklahoma, and Pennsylvania). Information was collected from each operation about animal numbers, feed and water use, manure handling and storage characteristics, field locations, crop rotation, fertilizer need, and equipment inventory and usage. Collected data were used as input and to validate results from a mechanistic model that determined acres required for manure application, manure application rate, time required for manure application, value of manure, and costs of manure management. The 39 farms had a mean of 984 animal units (AU) per operation, 18.2 AU ha−1 (7.4 AU acre−1), and manure application costs of $10.49 AU−1 yr−1 Significant factors affecting manure management included operation size, manure handling system, state, and ownership structure. Larger operations had lower manure management costs (r2 = 0.32). Manure value potentially exceeded manure application costs on 58% of slurry and 15% of lagoon operations. But 38% of slurry operations needed to apply manure off the farm whereas all lagoon operations had sufficient land for N‐based manure management. Manure management was a higher percentage of gross income on contract operations compared with independents (P < 0.01). This research emphasized the importance of site‐specific factors affecting manure management decisions and the economics of U.S. swine operations.
Application of a Slow‐Release Fertilizer for Oil Bioremediation in Beach Sediment
Authors: Xu R. , Lau N. L. A. , Ng K. L. , Obbard J. P.
Published: June 2010

A 105‐d field experiment was conducted to determine the potential of the slow‐release fertilizer, Osmocote (Scotts, Marysville, OH), to stimulate the indigenous microbial biodegradation of petroleum hydrocarbons in an oil‐spiked beach sediment on an intertidal foreshore in Singapore. Triplicate microcosms containing 80 kg of weathered sediment, spiked with 5% (w/w) Arabian light crude oil and 1.2% (w/w) Osmocote pellets, were established, together with control microcosms minus Osmocote. Relative to the control, the presence of the Osmocote sustained a significantly higher level of nutrients (NH4+–N, NO3−–N, and PO43−–P) in the sediment pore water over the duration of the experiment. The metabolic activity of the indigenous microbial biomass, as measured using an intracellular dehydrogenase enzyme assay, was also significantly enhanced over the duration of the experiment in amended sediments. The loss of total recoverable petroleum hydrocarbons (TRPH) and biodegradation of total n‐alkanes (C10–C33), branched alkanes (pristane and phytane), as well as total target polycyclic aromatic hydrocarbons (PAHs) (two‐ to six‐ring), in both the control and Osmocote‐amended sediments, followed a first‐order biodegradation model. The first‐order loss rate of total recoverable petroleum hydrocarbons was 2.57 times greater than that of the control. The hopane‐normalized rate constants for total n‐alkane, branched alkane, and total target PAH biodegradation in the Osmocote‐treated sediments were 3.95‐, 5.50‐, and 2.45‐fold higher than the control, respectively. Overall, the presence of Osmocote was able to significantly enhance and accelerate the biodegradation of aliphatics and PAHs in oil‐contaminated sediments under natural field conditions in an intertidal foreshore environment.
Tillage and Manure Application Effects on Mineral Nitrogen Leaching from Seasonally Frozen Soils
Authors: Gupta Satish , Munyankusi Emmanuel , Moncrief John , Zvomuya Francis , Hanewall Matt
Published: June 2010

Land application of manure is a common practice in the Upper Midwest of the United States. Recently, there have been concerns regarding the effect of this practice on water quality, especially when manure is applied during winter over frozen soils. A study undertaken on a Rozetta silt loam (fine‐silty, mixed, superactive, mesic Typic Hapludalfs) at Lancaster, WI, evaluated the effects of tillage and timing of manure application on surface and subsurface water quality. The daily scrape and haul liquid dairy manure was applied either in the fall (before snow) or in winter (over snow with frozen soil underneath) to be compared with no manure under two tillage systems (no‐till and chisel‐plowing). In this paper, we report results on the effects of the above treatments on mineral N leaching. Percolation and mineral N leaching during the nongrowing season were, respectively, 72 and 78% of the annual losses, mainly because of the absence of plant water and N uptake. Percolation was generally higher from no‐till compared with chisel‐plow but there was no significant effect of tillage on mineral N concentration of the leachate or mineral N losses via leaching. Mineral N leaching was statistically higher from the manure‐applied vs. no‐manure treatment, but there was no difference between winter‐applied manure and no‐manure treatments. There were significant tillage by manure interactions with fall manure application followed by chisel‐plowing resulting in highest N leaching losses. Averaged over the two years, N leaching rates were 52, 38, and 28 kg N ha−1 yr−1 from fall‐applied, winter‐applied, and no‐manure treatments, respectively. These results show that there is substantial N leaching from these soils even when no fertilizer or manure is applied. Furthermore, fall‐applied manure followed by fall tillage significantly increases N leaching due to enhanced mineralization of both soil and manure organic N.
In Situ Speciation Studies of Copper–Humic Substances in a Contaminated Soil during Electrokinetic Remediation
Authors: Liu S.‐H. , Wang H. Paul
Published: June 2010

Speciation of copper–humic substances (HS) in the electrokinetic remediation (EKR) of a contaminated soil was studied by in situ extended X‐ray absorption fine structure (EXAFS) and X‐ray absorption near edge structure (XANES) spectroscopies. The least‐square fits of the XANES spectra suggested that the main Cu species in the contaminated soil were Cu–HS (50%), CuCO3(28%), Cu2O (11%), and CuO (11%). The Cu–HS in the contaminated soil possessed equatorial and axial Cu–O bond distances of 1.94 and 2.17 Å with coordination numbers (CNs) of 3.6 and 1.4, respectively. In the EKR process, the axial Cu–O bond distance in the Cu–HS complexes was increased by 0.15 Å, which might be due to a ligand exchange of the Cu–HS with H2O molecules in the electrolyte. After 180 min of EKR, about 50% of the Cu–HS complexes (or 24% of total Cu) in the soil were dissolved and formed [Cu(H2O)6]2+in the electrolyte, 71% (or 17% of total Cu in the soil) of which were migrated to the cathode under the electric field (5 V/cm). This work exemplifies the use of in situ EXAFS and XANES spectroscopies for speciation studies of Cu chelated with HS in the contaminated soil during EKR.
Spectroscopic Speciation and Quantification of Lead in Phosphate‐Amended Soils
Authors: Scheckel Kirk G. , Ryan James A.
Published: June 2010

The immobilization of Pb in contaminated soils as pyromorphite [Pb5(PO4)3Cl, OH, F] through the addition of various phosphate amendments has gained much attention in the remediation community. However, it is difficult to fully determine the speciation and amount of soil Pb converted to pyromorphite by previously employed methods, such as selective sequential extraction procedures and scanning electron microscopy coupled with energy dispersive X‐ray spectroscopy, which often lead to erroneous results in these non‐equilibrated and heterogeneous systems. Statistical analysis by linear combination fitting (LCF) applied to X‐ray absorption fine structure (XAFS) spectroscopic data of Pb‐contaminated soil samples relative to known Pb reference material provides direct, in situ evidence of dominate Pb species in the amended soils without chemical or physical disruption to the Pb species as well as a weighted quantification output. The LCF–XAFS approach illustrated that pyromorphite concentration ranged from 0% (control soil) to 45% (1% phosphoric acid amendment, residence time of 32 mo) relative to the total Pb concentration. The Pb speciation in the nonamended control soil included Pb–sulfur species (galena + angelsite = 53%), adsorbed Pb (inner‐sphere + outer‐sphere + organic‐bound = 45%), and Pb–carbonate phases (cerussite + hydrocerussite = 2%). The addition of P promoted pyromorphite formation and the rate of formation increased with increasing P concentration (up to 45%). The supplemental addition of an iron amendment as an iron‐rich byproduct with triple superphosphate (TSP) enhanced pyromorphite formation relative to independent TSP amendment of like concentrations (41 versus 29%). However, the amendment of biosolids and biosolids plus TSP observed little pyromorphite formation (1–16% of total Pb), but a significant increase of sorbed Pb was determined by LCF–XAFS.
Sorption and Stability of the Polycyclic Nitramine Explosive CL‐20 in Soil
Authors: Balakrishnan Vimal K. , Monteil‐Rivera Fanny , Gautier Mathieu A. , Hawari Jalal
Published: June 2010

The polycyclic nitramine CL‐20 (2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane) is being considered for use as a munition, but its environmental fate and impact are unknown. The present study consisted of two main elements. First, sorption–desorption data were measured with soils and minerals to evaluate the respective contributions of organic matter and minerals to CL‐20 immobilization. Second, since CL‐20 hydrolyzes at a pH of >7, the effect of sorption on CL‐20 degradation was examined in alkaline soils. Sorption–desorption isotherms measured using five slightly acidic soils (5.1 < pH < 6.9) containing various amounts of total organic carbon (TOC) revealed a nonlinear sorption that increased with TOC [Kd (0.33% TOC) = 2.4 L kg−1; Kd (20% TOC) = 311 L kg−1]. Sorption to minerals (Fe2O3, silica, kaolinite, montmorillonite, illite) was very low (0 < Kd < 0.6 L kg−1), suggesting that mineral phases do not contribute significantly to CL‐20 sorption. Degradation of CL‐20 in sterile soils having different pH values increased as follows: sandy agricultural topsoil from Varennes, QC, Canada (VT) (pH = 5.6; Kd = 15 L kg−1; 8% loss) < clay soil from St. Sulpice, QC, Canada (CSS) (pH = 8.1; Kd = 1 L kg−1; 82% loss) < sandy soil provided by Agriculture Canada (SAC) (pH = 8.1, Kd = approximately 0 L kg−1; 100% loss). The faster degradation in SAC soil compared with CSS soil was attributed to the absence of sorption in the former. In summary, CL‐20 is highly immobilized by soils rich in organic matter. Although sorption retards abiotic degradation, CL‐20 still decomposes in soils where pH is >7.5, suggesting that it will not persist in even slightly alkaline soils.
Colloidal Phosphorus in Surface Runoff and Water Extracts from Semiarid Soils of the Western United States
Authors: Turner Benjamin L. , Kay Mary A. , Westermann Dale T.
Published: June 2010

Colloidal particles in runoff may have an important role in P transfer from soils to waterbodies, but remain poorly understood. We investigated colloidal molybdate‐reactive phosphorus (MRP) in surface runoff and water extracts of calcareous arable soils from the semiarid western United States. Colloidal MRP was determined by ultrafiltration and operationally defined as MRP associated with particles between 1 μm and 1 nm diameter, although a smaller pore‐size filter (0.3 nm) was used to define the lower size limit of colloids in water extracts. In surface runoff from three calcareous soils generated by simulated sprinkler irrigation, colloidal MRP concentrations ranged between 0.16 and 3.07 μM, constituting between 11 and 56% of the MRP in the <1‐μm fraction. Concentrations were strongly correlated with agronomic and environmental soil‐test P concentrations for individual soils. Water extracts of a range of similar soils contained two size fractions of colloidal MRP: a larger fraction (1.0–0.2 μm) probably associated with fine clays, and a smaller fraction (3–0.3 nm) probably associated with Ca–phosphate minerals. Colloidal MRP was solubilized in the acidic medium of the colorimetric detection procedure, suggesting that a fraction of the filterable MRP in runoff from calcareous soils may not be as readily bioavailable as free phosphate in waterbodies. Our results suggest that colloidal MRP is an important but poorly understood component of P transfer in runoff from calcareous western U.S. soils and should be given greater consideration in mechanistic studies of the P transfer process.
Assessing Ground Water Vulnerability with the Type Transfer Function Model in the San Joaquin Valley, California
Authors: Stewart Iris T. , Loague Keith
Published: June 2010

The recently developed type transfer function (TTF) simulation approach was applied to generate a regional‐scale nonpoint‐source ground water vulnerability assessment for the San Joaquin Valley, California. The computationally comparatively inexpensive TTF approach produces quantitative estimates of contaminant concentrations for large regional scales through characteristic functions based on different soil textures and their leaching properties. The TTF simulations employed an extensive soil and recharge database to estimate atrazine (1‐chloro‐3‐ethylamino‐5‐isopropylamino‐2,4,6‐triazine) concentrations at a compliance depth of 3 m resulting from a surface application. Two different sets of TTFs with two different levels of upscaling were used for spatially uniform and distributed recharge estimates. Results show that estimated atrazine concentrations can be related to soil survey information. Areas with high potential vulnerability to atrazine leaching were found for soils with low organic carbon content and sandy loam and loam textures. Travel times for atrazine peak concentrations to the compliance depth ranged from 350 to 730 d. The extent of areas with estimated atrazine concentrations above the maximum contaminant level was less extensive when uniform annual recharge values were used. Simulated TTF concentrations were highest for eastern Fresno County, a vulnerability pattern that is also supported by field observations. The TTF modeling approach is shown to be a useful tool for quantitative pesticide leaching estimates at regional scales significantly larger than those of previous studies.
Phosphorus Runoff from Incorporated and Surface‐Applied Liquid Swine Manure and Phosphorus Fertilizer
Authors: Daverede I. C. , Kravchenko A. N. , Hoeft R. G. , Nafziger E. D. , Bullock D. G. , Warren J. J. , Gonzini L. C.
Published: June 2010

Excessive fertilization with organic and/or inorganic P amendments to cropland increases the potential risk of P loss to surface waters. The objective of this study was to evaluate the effects of soil test P level, source, and application method of P amendments on P in runoff following soybean [Glycine max (L.) Merr.]. The treatments consisted of two rates of swine (Sus scrofa domestica) liquid manure surface‐applied and injected, 54 kg P ha−1 triple superphosphate (TSP) surface‐applied and incorporated, and a control with and without chisel‐plowing. Rainfall simulations were conducted one month (1MO) and six months (6MO) after P amendment application for 2 yr. Soil injection of swine manure compared with surface application resulted in runoff P concentration decreases of 93, 82, and 94%, and P load decreases of 99, 94, and 99% for dissolved reactive phosphorus (DRP), total phosphorus (TP), and algal‐available phosphorus (AAP), respectively. Incorporation of TSP also reduced P concentration in runoff significantly. Runoff P concentration and load from incorporated amendments did not differ from the control. Factors most strongly related to P in runoff from the incorporated treatments included Bray P1 soil extraction value for DRP concentration, and Bray P1 and sediment content in runoff for AAP and TP concentration and load. Injecting manure and chisel‐plowing inorganic fertilizer reduced runoff P losses, decreased runoff volumes, and increased the time to runoff, thus minimizing the potential risk of surface water contamination. After incorporating the P amendments, controlling erosion is the main target to minimize TP losses from agricultural soils.
Biological Effects of Wood Ash Application to Forest and Aquatic Ecosystems
Authors: Aronsson K. Andreas , Ekelund Nils G. A.
Published: June 2010

The present review aims to summarize current knowledge in the topic of wood ash application to boreal forest and aquatic ecosystems, and the different effects derived from these actions. Much research has been conducted regarding the effects of wood ash application on forest growth. Present studies show that, generally speaking, forest growth can be increased on wood ash–ameliorated peatland rich in nitrogen. On mineral soils, however, no change or even decreased growth have been reported. The effects on ground vegetation are not very clear, as well as the effects on fungi, soil microbes, and soil‐decomposing animals. The discrepancies between different studies are for the most part explained by abiotic factors such as variation in fertility among sites, different degrees of stabilization, and wood ash dosage used, and different time scales among different studies. The lack of knowledge in the field of aquatic ecosystems and their response to ash application is an important issue for future research. The few studies conducted have mainly considered changes in water chemistry. The biotoxic effects of ash application can roughly be divided into two categories: primary and secondary. Among the primary effects is toxicity deriving from compounds in the wood ash and cadmium is probably the worst among these. The secondary effects of wood ash are generally due to its alkaline capacity and a release of ions into the soil and soil water, and finally, watercourses and lakes. Given current knowledge, we would recommend site‐ and wood ash–specific application practices, rather than broad and general guidelines for wood ash application to forests.
Environmental Concentrations of Agricultural Herbicides in Saskatchewan, Canada: Bromoxynil, Dicamba, Diclofop, MCPA, and Trifluralin
Authors: Waite D. T. , Cessna A. J. , Grover R. , Kerr L. A. , Snihura A. D.
Published: June 2010

Herbicides are the most commonly used group of agricultural pesticides on the Canadian Prairies and, in 1990, more than 20000 Mg of herbicides were applied in the provinces of Alberta, Saskatchewan, and Manitoba. The present paper reports on environmental concentrations of five herbicides currently used in the prairie region. The herbicides bromoxynil [3,5‐dibromo‐4‐hydroxy‐benzonitrile], dicamba [3,6‐dichloro‐o‐anisic acid], diclofop [(RS)‐2‐[4‐(2,4‐dichlorophenoxy)‐phenoxy]propanoic acid], MCPA [(4‐chloro‐2‐methylphenoxy)acetic acid], and trifluralin [α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐isopropyl‐p‐toluidine] were measured in the atmosphere, bulk atmospheric deposits, surface film, and dugout (pond) water at two sites near Regina, Saskatchewan, during 1989 and 1990. All five herbicides were detected in air and surface film and all but trifluralin were detected in the bulk atmospheric deposits and dugout water. Trifluralin was most frequently detected in air (79% of samples) whereas bromoxynil was present in maximum concentration (4.2 ng m−3). MCPA was present in maximum levels in bulk atmospheric (wet plus dry) deposits (2350 ng m−2 d−1), surface film (390 ng m−2), and dugout water (330 ng L−1), whereas dicamba was most frequently detected in surface film (47%) and dugout water (97%). The highest quantities of the herbicides tended to be present during or immediately after the time of regional application.