Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Amendment Effects on Soil Test P after Long-Term Applications of Animal Manures

Authors
item Brauer, David
item Aiken, Glen
item Pote, Daniel
item Livingston, Stanley
item Norton, Lloyd
item Way, Thomas
item Edwards Jr, James

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 18, 2005
Publication Date: September 1, 2005
Citation: Brauer, D.K., Aiken, G.E., Pote, D.H., Livingston, S.J., Norton, L.D., Way, T.R., Edwards Jr, J.H. 2005. Amendment effects on soil test P after long-term applications of animal manures. Journal of Environmental Quality. 34:1682-1686.

Interpretive Summary: Applications of animal manures have increased soil test P values in many parts of the United States, and thus increased the risk that soil P will be transferred to surface water and decrease water quality. To continue farming in these areas, landowners need tools to reduce the risk of P moving off agricultural land. A field experiment was conducted near Kurten, TX to evaluate the effectiveness of soil amendments for reducing soil test P values. Gypsum applications of 5,000 pounds per acre were most effective in reducing soil test values for P, whereas a soil amendment made from waste paper was ineffective. These results are of interest to landowners who apply animal manure to fields for crop and forage production, and agricultural and natural resource professionals who advise landowners.

Technical Abstract: Applications of animal manures have increased soil test P values in many parts of the United States, especially where concentrated animal feeding operations dominate, and thus increased the risk that soil P will be transferred to surface water and decrease water quality. To continue farming in these areas, landowners need tools to reduce the risk of P moving off agricultural land. A field experiment was conducted near Kurten, TX to evaluate the effectiveness of soil amendments for reducing soil test P values. The site has received manure applications from dairy and egg laying operations for over 40 years. The soil is a Zulch fine sandy loam (thermic Udertic, Paleustalfs) with Bray 1 P values exceeding 1,000 mg P/kg soil (dry wt). Soils were amended annually for 3 years (1999 to 2001) with 1.5 and 5 Mg gypsum/ha, 1.4 Mg alum/ha or 24.4 Mg/ha a waste paper product high in Al. Additions of gypsum significantly reduced soil dissolved reactive P values; whereas additions of either alum or waste paper had little effect. Bray 1 P values were unaffected by soil amendment treatments. A laboratory study was conducted to determine the fate of added aluminum phosphate in three Zulch series soils differing in soil test P values and in Gilpin silt loam soil (mixed mesic, Typic Hapludult). Only 17% of the aluminum phosphate added to the Zulch series soil with the highest levels of soil test P was recovered in the aluminum phosphate fraction as compared to 76% for the Gilpin silt loam. These results suggest that the effectiveness of alum and waste paper to reduce soil dissolved reactive P is affected by chemical characteristics of the soil and its effect on the stability of aluminum phosphates.

Last Modified: 12/18/2014
Footer Content Back to Top of Page