Submitted to: American Society of Agronomy
Publication Type: Abstract Only
Publication Acceptance Date: 7/15/2004
Publication Date: 10/31/2004
Citation: Bundy, L.G., Studnicka, J.S., Powell, J.M. 2004. Manure handling and extraction procedure effects on determination of water-extractable phosphorus in manures [abstract]. American Society of Agronomy. Paper No. 4522. Interpretive Summary:
Technical Abstract: This study evaluated manure water-extractable phosphorus (WEP) measurements as a predictor of soluble phosphorus (P) in runoff following land application of manures. Water-extractable P concentrations were obtained with several methods and compared with dissolved reactive phosphorus (DRP) concentrations in simulated rainfall runoff following land applications of the same manures. Sample pretreatments prior to extractions were fresh (no pretreatment), frozen and thawed, and dried and ground manure. Water extraction ratios ranged 1:100 to 1:1000 with shaking times of one and two hours. Manure pretreatment, extraction ratio, and shaking time had significant effects on measured WEP concentrations with the 1:1000 extraction ratio and one hour shaking time, WEP increased in the order: dried and ground > fresh > frozen and thawed. WEP concentrations were significantly related to runoff DRP concentrations for all methods tested, but the 1:1000 ratio and one hour shaking time showed the best relationship (r2 = 0.97). Manure WEP measurements using the optimum extraction procedure have potential for predicting the risk of soluble P losses in runoff.