Submitted to: Soil Science Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/13/2007
Publication Date: 11/4/2007
Citation: He, Z., Honeycutt, C.W., Cade-Menun, B.J., Senwo, Z.N., Tazisong, I.A. 2007. Transformation of Organic P Forms of Poultry Litter in Soil Identified by Enzymatic Hydrolysis and P-31 NMR Spectroscopy. Soil Science Society of America Annual Meeting. CD-ROM Interpretive Summary:
Technical Abstract: Identification of the various phosphorus (P) forms in poultry litter coupled with knowledge of their transformations once added to soil will improve our understanding of long-term P roles in eutrophication. In this study, P in a poultry litter (PL) and a pasture soil with a 20-year history of PL application, was sequentially extracted with H2O, 0.5 M NaHCO3, 0.1 M NaOH, and 1 M HCl. After appropriate dilution and adjustment to pH 5.0, the fractions were incubated in the presence of orthophosphate-releasing enzymes. Parts of the enzymatically-treated and -untreated fractions were freeze dried for P-31 NMR analysis. NMR analysis demonstrated that the majority of enzymatically-untreated NaOH and HCl fractions were organic forms of P. These stable organic P forms could be subjected to enzymatic hydrolysis after being applied to soil, which was indeed supported by the soil P data. Compared to non-litter applied soil, 20-years of applying PL increased both labile and stable inorganic P pools in soil. However, repeated application of PL did not lead to significant build-up of hydrolyzable organic P in NaOH and HCl fractions, indicating that the stable (hydroxide and acid extractable) organic P must have been degraded to other forms. Degradation of stable PL organic P, as observed in this study, may be an important mechanism for maintaining a balance between labile and immobile P in soils.