Phosphorus Speciation in Manure and Manure-Amended Soils Using XANES Spectroscopy

Phosphorus Speciation in Manure and Manure-Amended Soils Using XANES Spectroscopy
S. Sato, D. Solomon, C. Hyland, Q.M. Ketterings, and J. Lehmann, NSLS Science Highlights, February 9, 2006

Department of Crop and Soil Sciences, Cornell University, Ithaca, NY
It is important to know what inorganic phosphorus (P) species are being formed in soils subjected to high, long-term poultry-manure application in order to understand P accumulation and release patterns. Phosphorus K-edge XANES spectra of fresh manure showed no evidence of crystalline P minerals, but did exhibit a dominance of soluble calcium phosphates (CaP) and free and weakly bound phosphates. Soils with a short-term manure history contained both Fe-associated phosphates and soluble CaP. Long-term application resulted in a dominance of CaP and a transformation from soluble to more stable CaP species. However, none of the amended soils showed the presence of crystalline CaP. Maintaining a high pH is therefore an important strategy that can be used to minimize P leaching in these soils.