2008 Joint Annual Meeting (5-9 Oct. 2008): Phosphorus Removal in Forage Production Systems That Utilize Animal Excrements.
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693-14 Phosphorus Removal in Forage Production Systems That Utilize Animal Excrements.



Tuesday, 7 October 2008
George R. Brown Convention Center, Exhibit Hall E
J. Clemn Turner, Oklahoma State University, 810 W 7th Ave, Stillwater, OK 74074-4506 and Jeffory Hattey, Oklahoma State University, Oklahoma St. Univ., 368 Ag Hall Plt & Soil Sci Dep, Stillwater, OK 74078-6028
Land application of swine effluent (SE) can provide essential plant nutrients for forage crop production, but phosphorus (P) additions can potentially be detrimental to the environment.  A multi-year study was conducted to evaluate the P balance from surface applied SE under several forage species in the semi-arid southern Great Plains.  Swine effluent and urea nitrogen (UN) was applied to supply 0, 56, 168, and 504 kg N ha-1 annually.  Soil P was measured initially in 1997 prior to any SE applications, then again in 2001 and 2006.  Soil P levels decreased from removal of forage biomass at a rate of 4.65 mg kg-1 yr-1 (r2=0.9416) at all N loading rates.  The significance of P removal over time extended dramatically, indicating that differences among treatments were increasing.  Phosphorus levels decreased in UN treatments from the lack of P additions; however in SE treatments, P levels were reduced at the lowest SE loading rates then raised slightly at the high N loading rates, due to the increased P loading from SE additions.  It was observed that at the 168 kg N ha-1 loading rate that P additions were almost equivalent to P removal from the biomass removal; suggesting that forage productions systems may adequately minimize and offset P risks associated with current environmental concerns.
See more of: Nutrient Availability and Environmental Risk from Land Application (Posters)
See more of: S08 Nutrient Management & Soil & Plant Analysis