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This article in JEQ

  1. Vol. 37 No. 2, p. 477-485
    Received: June 1, 2007

    * Corresponding author(s): jseiter@udel.edu
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XANES Spectroscopic Analysis of Phosphorus Speciation in Alum-Amended Poultry Litter

  1. Jennifer M. Seiter *,
  2. Kristin E. Staats-Borda,
  3. Matthew Ginder-Vogel and
  4. Donald L. Sparks
  1. Environmental Soil Chemistry Group, Dep. of Plant and Soil Sciences, and the Center for Critical Zone Research, Univ. of Delaware, 152 Townsend Hall, Newark, DE 19717


Aluminum sulfate (alum; Al2(SO4)3·14H2O) is used as a chemical treatment of poultry litter to reduce the solubility and release of phosphate, thereby minimizing the impacts on adjacent aquatic ecosystems when poultry litter is land applied as a crop fertilizer. The objective of this study was to determine, through the use of X-ray absorption near edge structure (XANES) spectroscopy and sequential extraction, how alum amendments alter P distribution and solid-state speciation within the poultry litter system. Our results indicate that traditional sequential fractionation procedures may not account for variability in P speciation in heterogeneous animal manures. Analysis shows that NaOH-extracted P in alum amended litters is predominantly organic (∼80%), whereas in the control samples, >60% of NaOH-extracted P was inorganic P. Linear least squares fitting (LLSF) analysis of spectra collected of sequentially extracted litters showed that the P is present in inorganic (P sorbed on Al oxides, calcium phosphates) and organic forms (phytic acid, polyphosphates, and monoesters) in alum- and non-alum–amended poultry litter. When determining land application rates of poultry litter, all of these compounds must be considered, especially organic P. Results of the sequential extractions in conjunction with LLSF suggest that no P species is completely removed by a single extractant. Rather, there is a continuum of removal as extractant strength increases. Overall, alum-amended litters exhibited higher proportions of Al-bound P species and phytic acid, whereas untreated samples contained Ca-P minerals and organic P compounds. This study provides in situ information about P speciation in the poultry litter solid and about P availability in alum- and non-alum–treated poultry litter that will dictate P losses to ground and surface water systems.

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Copyright © 2008. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyAmerican Society of Agronomy, Crop Science Society of America, and Soil Science Society of America