Progress 10/01/04 to 09/30/10
Outputs
OUTPUTS: This research focused on molecular-level mechanisms of phosphate, iron, and trace-element binding and mobilization in soils in the context of broader problems of concern in soil and environmental sciences. In conjunction with funded projects of more specific scope, results from this project were primarily disseminated through approximately 18 journal publications and book chapters, and more than 50 presentations at scientific meetings and in institutions around the world. Research discoveries made through this project were also incorporated into a graduate-level soil chemistry course taught annually at NC State University, which was attended by more than 80 students during the project period, representing disciplines of Soil Science, Crop Sciences, Biological and Agricultural Engineering, Civil Engineering, Horticultural Sciences, and Forestry. Moreover, this research formed the core focus of a Special Topics in Soil Chemistry course taught for graduate students at National Taiwan University in 2008 and 2010, which was attended by a total of approximately 75 students. I also provided training to two Ph.D.-level students from Taiwan and Sweden on the synchrotron x-ray methods advanced through this project. More specific outputs are specified in each of the annual project reports. PARTICIPANTS: Dr. Dean Hesterberg (Professor - Soil Chemistry) is the principal investigator. Other participants from NC State University included three Ph.D. students funded by a USDA-NRI grant - Ms. Yu-Ting Liu (Soil Science), Ms. Fiona Kizewski (Chemistry), and Ms. Amanda Morris (Soil Science). Collaborators in Sweden included a Ph.D. student (David Eveborn) and his advisor (Prof. Jon Petter Gustafsson at KTU in Stockholm) and Stephen Hillier from the Macaulay Institute in Aberdeen, Scotland. Collaborators in NC State CALS included Dr. David Buchwalter and a Ph.D. student, Justin Conley (Dept. of Toxicology); and Dr. Paul V. Nelson and a Ph.D. student, Ms. Ka Yeon Jeong (Dept. of Horticultural Sciences). TARGET AUDIENCES: This project developed and applied soil and environmental chemistry principals to a range of problems being addressed by scientists and practitioners in soil science, water quality, agricultural engineering, and horticultural sciences. Many of the advanced analytical techniques developed have broad applicability across scientific disciplines focused on complex, heterogeneous natural systems. Project results provide a mechanistic understanding for developing engineering practices for wastewater treatment, improved assessments for commercial greenhouse production, treatment and handling of animal wastes, and nutrient management in cropping systems. Outputs target not only practitioners, but contribute to the body of science in soil and environmental chemistry. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
A combination of research on the molecular-scale characteristics of trace-element and phosphate bonding in model systems and in natural samples brought insights that advanced our fundamental understanding of processes affecting chemical mobility in the environment. By advancing the development of synchrotron x-ray absorption spectroscopy as an analytical technique for chemical speciation in complex systems, this research project produced the following outcomes and impacts: 1. A method based on x-ray absorption near edge structure (XANES) spectroscopy was developed for determining the distribution of adsorbed inorganic orthophosphate between iron- and aluminum-oxide minerals in binary systems of mineral mixtures and co-precipitates. This outcome advanced characterization at the level achieved beyond that of single-mineral model systems, and provided a greater level of specificity than can presently be achieved in soils. This outcome further allowed us to determine mechanisms of phosphate dissolution during reduction of binary Al-/Fe-oxide systems. 2. Extension of the model-system research to treatment systems and field experiments showed mechanisms of phosphorus solubility changes in lime-treated poultry manure, and the basis of efficacies of different Ca-based filter systems aimed at removing phosphate from wastewater streams. 3. Speciation of arsenic in poultry litter stockpiles tied to the mobility of this and other trace elements in the piles and underlying soils. 4. Research on the kinetics of silver iodide precipitation from silver chloride shows the effectiveness of a potential geochemical barrier system for immobilizing radioactive iodine from high level wastes. 5. Analysis of cobalt oxidation states when substituted into an iron oxide mineral provided information for determining mechanisms of siderophore-promoted dissolution of iron and cobalt. 6. Chemical principles of multi-component element binding and transport in soils, and redox chemistry, were coupled with hydrological measurements and modeling to the relationship between drainage water composition and accumulation of plant nutrients (particularly N, K, Ca, Mg, and Mn) in different soil zones.
Publications
- Bi, Y.Q., D.L. Hesterberg, and O.W. Duckworth. 2010. Siderophore-promoted dissolution of cobalt from hydroxide minerals. Geochimica Et Cosmochimica Acta 74:2915-2925. Hashimoto, Y., T.J. Smyth, D.W. Israel, and D. Hesterberg. 2010. Lack of soybean root elongation responses to micromolar magnesium additions and fate of root-exuded citrate in acid subsoils. Journal of Plant Nutrition 33:219-239. Kizewski, F.R., P. Boyle, D. Hesterberg, and J.D. Martin. 2010. Mixed anion (phosphate/oxalate) bonding to iron(iii) materials. Journal of the American Chemical Society 132:2301-2308.
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: The basic component of this research focuses on redox chemistry affecting soil phosphate binding and mobility. We also provided soil and environmental chemistry support to a number of other research projects in the College of Agriculture and Life Sciences at NC State University and research groups around the world. Results of a study on x-ray absorption near edge structure (XANES) spectroscopy of phosphorus in wastewater treatment media was published in Environmental Science and Technology. This work was in conjunction with researchers in Sweden and the United Kingdom. Research on selenium bioaccumulation in a periphyton biofilm from contaminated stream water and transfer into grazing mayfly larvae utilized synchrotron x-ray absorption spectroscopy and techniques developed in conjunction with toxicologists to determine effects of selenite versus selenate on accumulated species. Results were included in a presentation at the 30th Annual Society of Toxicology and Chemistry (SETAC) North American meetings. We also assisted a student in horticultural sciences to develop a rapid pH titration method for assessing lime requirements of potting media used in greenhouse production. This new technique, including modeling to show the underlying organic matter chemistry was presented at an American Society of Horticultural Sciences meeting. I wrote a book chapter giving a comprehensive overview of phosphorus chemistry in soils in relation to chemical speciation analysis using synchrotron x-ray absorption spectroscopy. The chapter has been accepted for publication. PARTICIPANTS: Dr. Dean Hesterberg (Professor - Soil Chemistry) is the principal investigator. Other participants from NC State University included three Ph.D. students funded by a USDA-NRI grant - Ms. Yu-Ting Liu (Soil Science), Ms. Fiona Kizewski (Chemistry), and Ms. Amanda Morris (Soil Science). Collaborators in Sweden included a Ph.D. student (David Eveborn) and his advisor (Prof. Jon Petter Gustafsson at KTU in Stockholm) and Stephen Hillier from the Macaulay Institute in Aberdeen, Scotland. Collaborators in NC State CALS included Dr. David Buchwalter and a Ph.D. student, Justin Conley (Dept. of Toxicology); and Dr. Paul V. Nelson and a Ph.D. student, Ms. Ka Yeon Jeong (Dept. of Horticultural Sciences). TARGET AUDIENCES: This project develops and applies soil and environmental chemistry principals to a range of problems being addressed by scientists and practitioners in soil science and other fields of study. Project results provide a mechanistic understanding for developing engineering practices for wastewater treatment, improved assessments for commercial greenhouse production, while contributing to the body of science accessed by other scientists and practitioners. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
XANES spectroscopy was used to help develop and evaluate bed filters as sustainable on-site wastewater treatment systems for removing phosphorus. Phosphorus species were characterized using phosphorus K-edge XANES and other spectroscopic analyses of full-scale, operational wastewater-treatment systems and filter samples collected from laboratory studies. No systematic differences could be seen in the results between laboratory and full-scale samples. The analysis showed calcium phosphates of different cystallinities forming in all media evaluated. Some samples also contained more than 35% of accumulated phosphorus associated with Fe or Al. Selenium speciation in biofilms and mayfly larva showed no difference in oxidation state in the biological systems, regardless of whether selenite or selenate was the dominant form (oxidation state) of selenium in simulated stream water. A laboratory titration method for greenhouse potting media gave hundreds of titration points within 1 hour, compared with 10s of points collected by conventional incubation in the greenhouse for 3 days. The titration method accurately predicted the lime requirement determined by the conventional method for pH adjustments up to an optimal of pH 6.2. Above this pH, deviations could be explained by the carbon-dioxide regulated solubility of calcite in the greenhouse compared with strong acid/base titration in the laboratory, as determined by geochemical speciation analyses. This new adaptation of a conventional soil chemistry method could prove to be very cost effective in greenhouse production systems.
Publications
- Eveborn, D., J. P. Gustafsson, D. Hesterberg, and S. Hillier. 2009. XANES speciation of P in environmental samples: an assessment of filter media for on-site wastewater treatment. Environmental Science and Technology 43:6515-6521.
- Shah, S. B., K. J. Hutchison, D. Hesterberg, G. L. Grabow, R. L. Huffman, D. H. Hardy, and J. T. Parsons. 2009. Leaching of nutrients and trace elements from stockpiled turkey litter into soil. Journal of Environmental Quality 38:1053-1065.
- Jeong, K.Y., D. Hesterberg, P. Nelson, and J. Frantz. 2009. Predicting Calcite (CaCO3) Requirements of Sphagnum Peat Moss from pH Titration Curves. Hortscience 44:1020-1020.
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Results from various research areas covered by this project were disseminated to the scientific community through a book chapter and peer-reviewed journal publications that are submitted, in review, or accepted for publication, and a poster presented to soil and environmental scientists at an international professional society meetings. A comprehensive book chapter on synchrotron x-ray absorption spectroscopy of soil minerals is now published. Two journal publications on arsenic in stockpiled turkey litter (Sha et al., accepted; and Hutchison et al., in review/revision) are underway, and a publication on soil organic matter effects on phosphorus retention (sorption) in soil has been accepted for publication. PARTICIPANTS: Dr. Dean Hesterberg (Professor - Soil Chemistry) is the principal investigator. Other participants from NC State University included Dr. Jihoon Kang, a recent Ph.D. graduate in Soil Science co-advised by Dr. Hesterberg and working on phosphate bonding in soils. In addition, three Ph.D. students funded by a USDA-NRI grant - Ms. Yu-Ting Liu (Soil Science), Ms. Fiona Kizewski (Chemistry), and Ms. Amanda Morris (Soil Science) are conducting research that falls under the overall objectives of this project. TARGET AUDIENCES: This project discovers soil chemistry principals that can be applied to problems being addressed by both scientists and practitioners in various fields of science and industries. Project results provide a mechanistic understanding for developing phosphate indices needed by nutrient-managers to maintain agricultural productivity while minimizing negative environmental impacts of phosphorus on water quality. Research related to soil phosphate dissolution under reducing redox conditions is relevant to scientists and engineers that are involved in creating or restoring wetlands from agricultural lands that have received inputs of phosphorus fertilizers. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
This project applies soil chemistry toward solving agricultural and environmental problems related to phosphate. Research on phosphorus binding in soils as affected by organic matter complements an ongoing USDA-NRI funded research project on the molecular mechanisms of phosphate bonding to minerals, organic matter, and mineral-organic systems. For soils, a statistical analysis (path analysis) was used to determine direct and indirect effects of soil properties on the maximum phosphate sorption capacity. Results indicated that oxalate-extractable Al, soil clay concentration, and oxalate-extractable Fe were, in that order, significant soil properties affecting maximum P sorption capacity of soils. A segmented linear relationship existed between maximum sorption capacity and soil organic matter (OM), with the regression slope for soils with OM concentrations less than 49 g/kg being ten-fold greater than that for soils with OM concentration 49 g/kg. This finding suggested that non-crystalline or organically bound Al and Fe in soils of lower OM concentration was more effective for P sorption than that in the soils with lower OM concentration. The book chapter on synchrotron x-ray absorption spectroscopy (XAS) analysis of soil minerals is considered the most comprehensive chapter written on this subject. It details how to prepare samples, collect XAS data, and analyze both the x-ray absorption near edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) parts of spectra. Numerous researchers in this area have requested or been given reprints of this chapter to assist in learning intricacies of XAS data analysis.
Publications
- Kelly, S., D. Hesterberg, and B. Ravel. 2008. Analysis of soils and minerals using x-ray absorption spectroscopy. p. 387-463 In A. L. Ulery and R. Drees (Ed.) Methods of Soil Analysis. Part 5. Mineralogical Methods. Soil Sci. Soc. Am., Madison, WI.
- Kang, J., Amoozegar, A., Hesterberg, D, and Osmond, D.L. 2008. Soil organic matter effects on phosphorus sorption: a path analysis. Abstracts of Joint GSA/ASA-CSSA-SSSA International Annual Meeting. Houston, TX, U.S.A. (742-10).
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: Results from various research areas covered by this project were disseminated to the scientific community through three peer-reviewed journal publications, and two posters presented to soil and environmental scientists at international and state (North Carolina) professional society meetings.
PARTICIPANTS: Dr. Dean Hesterberg (Professor - Soil Chemistry) is the principal investigator. Other participants from NC State University included Dr. Jihoon Kang, a recent Ph.D. graduate in Soil Science co-advised by Dr. Hesterberg and working on phosphate bonding in soils; Ms. Daphine McKinney, a Ph.D. student in Dr. Hesterberg's laboratory working on geosorbents; and Dr. Janet Rippey and Ms. Ka-Yeon Jeong working with Dr. Paul Nelson in Horticultural Sciences at NC State University.
TARGET AUDIENCES: This project applies soil chemistry principals to problems being addressed by both scientists and practioners in various fields of science and industries. Project results would provide a mechanistic understanding for developing phosphate indices needed by nutrient-managers to maintain agricultural productivity while minimizing negative environmental impacts of phosphorus on water quality. Research on iodide applies to the development of safe systems for permanently storing high-level radioactive waste from the nuclear power industry, particularly at the Yucca Mountain repository. Research on horticultural media is broadly applicable throughout the horticultural greenhouse industry, both to industry practitioners and scientists developing more cost-effective production systems that minimize nutrient discharge from greenhouses.
Impacts
Research under this project applied soil chemistry to various agricultural and environmental issues; including phosphate impacts on the environment, production horticulture, and developing geosorbents for high-level radioactive wastes. Research on phosphorus binding in soils complements an ongoing USDA-NRI funded research project on the molecular mechanisms of phosphate bonding in clay-organic systems. To apply such knowledge to managing agricultural phosphorus, the maximum adsorption capacities of more than 70 soil samples were measured as part of another project. Fundamental knowledge about phosphate-organic matter interactions gained through our basic research in this area provided insight to understanding why the maximum phosphate sorption capacity of the coastal plain soils evaluated increased with increasing organic matter, but the slope of this linear relationship decreased when soil samples contained more than 50 g organic matter/kg soil. Both iron(III) and
aluminum(III) appear to be the dominant phosphate-sorbing cations involved, but the accessibility to these cations seems to decrease in the soil samples with greater organic matter concentration. Statistical analysis indicated an indirect effect of organic matter on phosphate sorption in relation to poorly-crystalline or organic-matter bound aluminum(III). Our basic research suggested that the amount of phosphate sorbed per unit iron(III) bound to soil organic matter depends on whether or not polynuclear hydroxy-iron(III) clusters form in the organic matter, and phosphate showed a binding preference for organic-bound aluminum over iron. Research on geosorbents for scavenging iodide from high-level radioactive waste showed that silver-chloride could potentially immobilize anionic iodide by forming insoluble silver-iodide. As an alternative geosorbent, silver ions bound with allophanic soil also react with iodide to form silver iodide. Greenhouse experiments in horticulture evaluated
the efficacy of various limestones in relation to properties like specific surface area and purity of the limestone. This information useful for optimizing productivity of greenhouse systems. Moreover, acid-base titrations of peats and composts accurately predicted the amounts of lime needed to neutralize the native acidity of these media when used in soilless greenhouse systems. This fairly rapid laboratory procedure precludes the need for a more cumbersome approach of incubating the media with various concentrations of lime to determine the optimal liming rate.
Publications
- Khare, N., Martin, J. D., and Hesterberg, D. (2007). Phosphate bonding configuration on ferrihydrite based on molecular orbital calculations and XANES fingerprinting. Geochimica et Cosmochimica Acta, 71:4405-4415.
- McKinney, D. and Hesterberg, D. (2007). Kinetics of AgI precipitation from AgCl as affected by background electrolyte. Journal of Radionuclear Chemistry, 237:289-297.
- Rippy, J.F.M., Nelson, P.V., and Hesterberg, D. L. (2007). Reaction times of twenty limestones. Comunications in Soil Science and Plant Analysis, 38:1775-1783.
- Kang, J., Amoozegar, A., Hesterberg, D, and Osmond, D.L. 2007. Effect of inorganic and organic phosphorus sources on phosphorus leaching loss in a sandy soil. Soil Science Society of North Carolina Annual Meeting. Jan. 16-17, 2007. Raleigh, NC.
- Kang, J., Hesterberg, D., Amoozegar, A., and Osmond, D. 2007. Phosphorus Leaching in a Sandy Soil Affected by Fertilizer Sources. Abstracts of ASA-CSSA-SSSA 2007 International Annual Meeting. New Orleans, LA, U.S.A. (119-12).
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Progress 10/01/05 to 09/30/06
Outputs
Redox potential and pH are the two master variables that control most chemical processes in soils. Our main focus under this project was on reduction of soils and dissolution of iron oxide minerals. These redox driven processes potentially affect the mobility of plant nutrients (phosphorus) and contaminants (arsenic, copper, zinc, lead, etc.) because iron- (and aluminum-) oxide minerals are the principal sorbents of these elements in soils. Also, determining the relationships between Fe(III) reduction rates and variables such as amount and type of organic matter will improve the accuracy of wetland delineation and the effectiveness of wetland restoration. Because of the complexity of soil organic matter and its connection to electron acceptors such as Fe-oxides, predicting rates of soil reduction under water-saturated conditions is not quantitative. Laboratory incubation experiments were completed on soils from two toposequences to determine how soil properties affect
the rate of reduction under water-saturated conditions. Three reduction-oxidation cycles were imposed. In a related study, we characterized the forms (species) of iron in redoximorphic features - iron depletions and accumulations - in a forested subsoil. Redoximorphic features typically form in soils that undergo periods of reduction (water saturation) and oxidation. Laboratory incubation studies showed rapid reduction following saturation with water. Redox potential (Eh) decreased from an average of 360 mV to -105 mV within 5 days for most soils, but was slower for upland soils. Reduction rate was usually faster during the first redox cycle than in subsequent cycles. The reduction rate in the first cycle increased with increasing soil organic carbon concentration and pH. Trends in dissolved Fe(II) during reduction fell into three groups: (i) no increase in Fe(II) with decreasing Eh (Ponzer O horizons, Leon E horizon, and Lynchburg B horizon); (ii) moderate increases up to 60
micromolar Fe(II) (Rains B horizon, and Lynchburg E horizon, (iii) large increases up to 400 micromolar Fe(II) at Eh < 200 mV (Pantego A and B horizons). A statistical model indicated that soil reduction under water saturated conditions increased with increasing organic matter or pH. Synchrotron x-ray absorption spectroscopy (XAFS) results for iron in redoximorphic features indicated that the following forms of Fe were most prevalent (given as a percentage of total Fe): 39% goethite, 36% hematite, and 25% organic-matter bound Fe (reddish-colored accumulations); and 63% organic matter bound Fe and 37% goethite (yellowish-colored depletions). These results led to the hypothesis that organic matter disaggregation during reductive dissolution of Fe(III) might help drive the spatially-variable formation of redoximorphic features. On the other hand, the greater abundance of organic-associated Fe in zones of Fe depletion suggested that organic matter might serve to stabilize this residual
iron. Perhaps this iron also stabilizes the organic matter.
Impacts
Dramatic changes in soil chemistry occur after a soil is wetted or dried. Of particular concern is release of phosphorus and potentially-toxic metals like arsenic and lead into the soil water during wet periods. Such dissolution (release) increases the movement of these substances in the environment, and is often linked to dissolution iron-bearing soil minerals. Iron mineral dissolution also results in colored soil features that are used to identify wetlands. During land development, there can be no net loss of wetlands under Federal laws. Our research showed that soils from a variety of locations in NC underwent chemical changes within 5 days of inundation with water. In some but not all cases, these chemical changes resulted in iron minerals dissolving. The amount of organic matter (mainly plant-derived residues) and pH were the two main soil properties affecting how quickly chemical changes occurred after water saturation. Other research indicated that interactions
between iron and soil organic matter have a role in the movement of iron that is essential for identifying and preserving natural wetlands.
Publications
- Hesterberg, D., A.B. de Vos, and P.A.C. Raats. 2006. Chemistry of subsurface drain discharge from an agricultural polder soil. Agricultural Water Management. 86:220-228.
- Shober, A. L., D. L. Hesterberg, J. T. Sims, and S. Gardner. 2006. Characterization of phosphorus species in biosolids and manures using XANES spectroscopy. Journal of Environmental Quality 35: 1983-1993.
- Murray, G. C. and D. Hesterberg. 2006. Iron and phosphate dissolution during abiotic reduction of ferrihydrite-boehmite mixtures. Soil Science Society America Journal 70:1318-1327.
- Maguire, R. O., D. Hesterberg, A. Gernat, K. Anderson, M. Wineland, and J. Grimes. 2006. Liming poultry manures to kill pathogens and decrease soluble phosphorus. Journal of Environmental Quality 35:849-857.
- Fichtner, E. J., D. L. Hesterberg, T. J. Smyth, and H. D. Shew, H. D. 2005. Differential sensitivity of Phytophthora parasitica var. nicotianae and Thielaviopsis basicola to monomeric Al species. Phytopathology 96:212-220.
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Progress 10/01/04 to 09/30/05
Outputs
Research focused on two issues related to agriculture and the environment: 1. release of phosphate from soil particles to soil water as affected by redox conditions; and 2. movement of arsenic through soil underlying poultry litter stockpiles. Phosphorus, a major plant nutrient, negatively impacts water quality when it moves from agricultural fields to surface waters. To understand how soil particles bind and release inorganic phosphate during soil reduction following saturation with water, our research addressed molecular-scale interactions between phosphate and soil or synthesized mineral particles. Phosphate binding and release (dissolution) mechanisms in mineral mixtures consisting of redox-active iron (Fe) oxides and redox-inert aluminum (Al) oxides were studied using synchrotron x-ray absorption near-edge structure (XANES) spectroscopy and laboratory redox reactors. A significant finding was that phosphate binding and dissolution mechanisms in mineral mixtures
could not always be projected from an understanding of systems containing each of the component minerals individually. That is, mineral interactions alter phosphate chemistry. For example, precipitation of Al-phosphate in an aqueous suspension containing only non-crystalline Al-hydroxide caused the maximum phosphate sorption capacity of the system to exceed that expected when the Al-hydroxide was mixed with ferrihydrite (poorly-crystalline iron oxide). The presence of ferrihydrite inhibited Al-phosphate precipitation and diminished the sorption capacity. Abiotic reductive dissolution of Fe-oxide minerals and associated phosphate was strongly inhibited by minor additions of Al-oxide to ferrihydrite suspensions (< 0.04 g boehmite/g ferrihydrite). Supporting experiments indicated that aluminum dissolved from boehmite and binds to the Fe-oxide surface, passivating it against reduction. XANES showed some evidence for Al-phosphate precipitation as these mineral mixtures underwent reduction.
Separate studies on soil materials showed that organic matter plays a key role in phosphate release into soil water during reduction. Poultry litter contains plant macronutrients such as nitrogen (N) and phosphorus (P), and trace elements such as copper (Cu), zinc (Zn), and arsenic (As) that can negatively affect water quality if land application is not properly managed. This field-based research determined the extent that stockpiling of poultry litter enhanced the subsoil contamination and leaching of potentially-harmful elements, particularly As. Soil samples collected before and after stockpiling litter for periods of months showed contamination and movement of As, Cu, Zn, P, and other elements to more than 20 cm depth under stockpiles compared with non-impacted locations between stockpiles. Analysis of poultry stockpile samples indicated that the roxarsone added to poultry feeds and present in the original litter was transformed into inorganic As during stockpiling. Although the
areal extent of soils bearing stockpiles is limited, contamination of these areas is significant in less than one year of stockpiling.
Impacts
Basic research addressing how phosphorus is bound to soil particles promotes ways to maximize crop benefits of soil-applied phosphorus while minimizing negative impacts on water quality and the environment. Whereas past research on model systems containing single minerals has been extremely valuable, future work involving increasingly complex systems containing multiple minerals and organic matter is essential for revealing exactly how soils can be manipulated to optimize phosphorus management. With regard to animal waste management, methods such as impervious covers should be used to diminish movement of potentially-harmful elements such as arsenic from poultry litter stockpiles into the underlying soil.
Publications
- Pfeifer, H. R., A. Gueye-Girardet, D. Reymond, C. Schlegel, E. Temgoua, D. Hesterberg, and J. W. Chou. 2004. Dispersion of natural arsenic in the Malcantone watershed, Southern Switzerland: field evidence for repeated sorption-desorption and oxidation reduction processes. Geoderma 122:205-234.
- Hutchison, K. J. and D. Hesterberg. 2004. Dissolution of phosphate in a phosphorus-enriched Ultisol as affected by microbial reduction. Journal of Environmental Quality 33:1793-1802.
- Khare, N., D. Hesterberg, and J. D. Martin. 2005. Investigating phosphate surface precipitation in single and binary mixtures of Fe- and Al-oxide minerals using XANES. Environmental Science and Technology. 39:2152-2160.
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