|Senwo, Zachary - A&M UNIVERSITY|
|Mankolo, Regine - A&M UNIVERSITY|
Submitted to: Organic P Workshop
Publication Type: Abstract Only
Publication Acceptance Date: July 15, 2004
Publication Date: August 15, 2004
Citation: He, Z., Senwo, Z., Mankolo, R., Honeycutt, C.W. 2004. Distribution of phosphorus species in poultry litter characterized by sequential fractionation coupled with phosphatase hydrolysis. Organic P Workshop. August 16-19, 2004. Wageningen, The Netherlands. Page 18. Technical Abstract: The chemical composition of phosphorus in manure significantly impacts its transport and potential bioavailability. Increased knowledge of manure P chemistry is therefore required to optimize recycling of manure P and minimize the adverse environmental effects of animal manure application to cropland. In this study, the distribution of P forms in 15 poultry litters was investigated with sequential fractionation coupled with orthophosphate-releasing enzymatic hydrolysis. Manures were first sequentially fractionated into H2O-soluble, NaHCO3-soluble, NaOH-soluble, and HCl-soluble P. Fractions were then incubated in 100 mM sodium acetate (pH 5.0) with 1) potato acid phosphatase, 2) potato acid phosphatase and nuclease P1, and 3) both enzymes plus wheat germ acid phosphatase to identify and quantify simple labile monoester P, nucleotide P, and phytate (myo-inositol hexakisphosphate)-like P, respectively. The majority of P in the 15 poultry litters was distributed in H2O and HCl fractions (about 30%, and 40% of total manure P, respectively). In contrast, NaHCO3 and NaOH fractions contained only 10-20% of total manure P. However, P species in these fractions were different. Inorganic P accounted for 80% of P in H2O fractions, and 70% of P in NaHCO3 fractions. Only 5-15% of P in the two fractions was enzymatically hydrolysable organic P. In NaOH and HCl fractions, 50 to 90% of P was present in organic forms. Among them, 40-70% was phytate-like P and 10-30% was simple monoester P. Findings in this study indicate that poultry litter contained similar amounts of easily bioavailable P (H2O- and NaHCO3- extracted inorganic P and hydrolyzable organic P) and stable P (NaOH- and HCl-extracted P). These properties must be considered when developing sustainable P management practices for poultry litter.