Net Phosphorus Extractability from Soils Amended with Cattle Manure. (S11-schwartz131384-poster)
Authors:
R.C. Schwartz* - USDA-ARS T.H. Dao - USDA-ARS
Abstract:
Soils amended with animal wastes increase environmental risks associated with elevated concentrations of dissolved phosphorus in runoff. The objective of this study was to determine the influence of beef cattle manure characteristics and P application rate on net extractability of P. A Pullman silty clay loam (fine, mixed, superactive, thermic Torrertic Paleustoll) was amended with monocalcium phosphate (MCP) and four sources of beef manure at differing stages of maturity. Soil was amended at rates of 0, 31.25, 62.5, 125, and 250 mg total P kg-1 soil and incubated for 63 days. Extractable P in incubated soils was determined using the Mehlich 3 (M3-P), Olsen (O-P) and Texas A&M (TAM-P) extractants, and with deionized water (W-P). Extractable P increased linearly with application rate (P less than 0.0001) for all sources and extractants, with slight (P less than 0.05) negative and positive quadratic responses for M3-P and TAM-P, respectively. Net extractable P ranged from 6% to 79% of P application rate and differed widely among P sources. Extractable M3-P and TAM-P increased with increasing age of manures. The efficiency with which P was extracted in manures relative to MCP differed significantly among all extractants. Differences in extractability among manures imply that management of manure P may have to consider manure characteristics in addition to edaphic and climatic factors.
Speaker Information: Robert Schwartz, USDA-ARS, PO Drawer 10, Bushland, TX 79012; Phone:
806-356-5762; E-mail: [email protected]
Session Information: Wednesday, November 5, 2003, 3:30 PM-5:30 PM Presentation Start: 3:30 PM (Poster Board Number: 1315)
Keywords: Soil test phosphorus; Manure management; Manure application rate; Water quality
