Submitted to: Trade Journal Publication
Publication Type: Trade Journal
Publication Acceptance Date: September 4, 2004
Publication Date: September 15, 2004
Citation: Griffin, T.S., Honeycutt, C.W., He, Z. 2004. Cca advantage ceu module: changes in soil phosphorus from manure application. AG Professional. Technical Abstract: Manure and fertilizer phosphorus (P) sources vary in their contributions to soil P pools. By incubating soil+ manure mixtures in the lab under constant temperature and moisture conditions, we are able to evaluate changes in soil P concentration for 84 days following application of fertilizer or manure (beef, dairy, poultry, or swine), and also evaluate interactive effects of P rate, P source and background P level on these soil P pools. Changes in soil P over time followed amendment (100 mg total P kg-1) of a sandy loam soil (pH 5.8). Water soluble P (WSP), CaCl2-extractable P (CaCl2-P), and modified Morgan P (MMP) declined to less than 2 parts per million (PPM) of soil within 21 days of application; P extracted by anion exchange membrane (AEMP) and Mehlich-III (M3P) also declined rapidly due to the high level of exchangeable aluminum (Al) and iron (Fe) in this soil. Ninety days after application, all soil P pools exhibited linear increases in concentration, regardless of P source. Fertilizer P was more efficient at increasing CaCl2-P and M3P. Manure P sources generally had a greater effect on MMP, where poultry manure was more efficient than all other sources. Efficiency of P sources at increasing soil test P concentration varied from less that 1% for rapidly available P pools (CaCl2-P) to nearly 50% for more recalcitrant P (M3P). The amount of soluble P increased rapidly when soil P saturation exceeded 25%. Manure and fertilizer P contribute to different soil P pools, and these differences are magnified at high application rates and high background soil P levels. This information helps us better manage manure and soil P.