Distribution of Phosphorus Species in Dairy Manure.
(S08-he305059-oral)
Authors:
Z. He* - USDA-ARS
T.S. Griffin - USDA-ARS, Orono, ME C.W. Honeycutt - USDA_ARS, Orno, ME
Abstract:
The chemical composition of manure P is a key factor determining its potential bioavailability and susceptibility to runoff. The distribution of P forms in 13 dairy manures was investigated with sequential fractionation coupled with orthophosphate-releasing enzymatic hydrolysis. A large portion of manure P was H2O extractable, varying from 1,400 to 6,810 mg inorganic P (Pi) kg-1 DM and 130 to 1,660 mg organic P (Po) kg-1 DM. In the NaHCO3 fraction, Pi varied between 740 and 4,200 mg P kg-1 DM, and Po varied between 340 and 1,550 mg P kg-1 DM. In the NaOH fraction, Pi fluctuated around 200 mg P kg-1 DM, and Po ranged from 130 to 630 mg P kg-1 DM. Phytate-like P was present as the major hydrolysable Po in all three fractions (26 to 605 mg kg-1 DM). Although the concentrations of P species varied significantly in these manures, correlations among some P forms with total manure P were observed. For example, H2O-extracted Pi was correlated with total manure P (r =0.79), and
NaOH-extracted Po was correlated to total manure P (r =0.91). We also demonstrated that P released by a single extraction with sodium acetate (100 mM, pH 5.0) was equal to the summed amount of H2O-, NaHCO3-, and NaOH-extractable P fractionated sequentially. Thus a single extraction by sodium acetate buffer could provide an efficient evaluation of plant available P in animal manure, while the sequential fractionation approach provides more detailed characterization of manure P.
Speaker Information: Zhongqi He, USDA-ARS, USDA-ARS, New England Plant, Soil, and Water Lab,, Orono, ME 04401; Phone: (207) 581-3373; E-mail: [email protected]
Session Information: Wednesday, November 5, 2003, 1:25 PM-4:00 PM Presentation Start: 1:30 PM
Keywords: manure P; dairy manure; organic P; phosphatase
