Date Full Report Received06/05/2007
Date Abstract Report Received06/05/2007
InvestigationInstitution: Oklahoma State University
Primary Investigator: Shiping Deng
Co-Investigators: Jeff Hattey
Funded ByNational Pork Board
Annual swine effluent application in western Oklahoma for 11 consecutive years did not lead to significant accumulation of soil phosphorus. Similar trend was shown in a century-old field experiment in central Oklahoma. Although phytate is the main phosphorus form in animal feeding stuff, it has little nutritional value for monogastric animals and was suspected to be responsible for high P levels in animal manures. Laboratory studies showed that phytate added to soil did not remain in the solution and had limited mobility in soil columns that were constructed with acidic or alkaline soil. Therefore, solution phosphorus levels in soils were not increased appreciably by the addition of phytate to soil and manure-phosphorus would have limited mobility in the environment. Application of manure, however, enhanced soil biological activities and the capacity of soil to retain or cycle nutrients. Long-term manure application in central and western Oklahoma sustained agricultural production and did not result in P accumulation to levels close to those in inorganic P fertilizer-treated soils.