ARS | Publication request: EFFECTS OF DRYING ON PHOSPHORUS DISTRIBUTION IN POULTRY MANURE

Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 11, 2006
Publication Date: July 1, 2007
Citation: Waldrip Dail, H.M., He, Z., Erich, M.S., Honeycutt, C.W. 2007. Effects of drying on phosphorus distribution in poultry manure. Communications in Soil Science and Plant Analysis. 38:1879-1895

Interpretive Summary: Manure samples are frequently dried prior to laboratory analysis. Drying has the capacity to alter manure characteristics. Thus, evaluation of the effect of different drying processes on the distribution of phosphorus (P) fractions in animal manure may improve accuracy of manure analysis and data comparison. Phosphorus fractions in air-dried, oven-dried, and freeze-dried samples of three poultry manures were analyzed and compared to undried manures. Findings in this study indicate that drying can transform manure P from one form to another. Particularly, we found that high-temperature drying increased the amount of water soluble P in all three tested manures. Our results indicate that the method of sample drying should be considered when comparing data from different laboratories.

Technical Abstract: Laboratory drying may alter manure phosphorus (P) distribution. We examined effects of freeze-, air (22oC)-, and oven (65oC)-drying on sequentially fractioned poultry manure P. Higher drying temperatures resulted in lower percent dry matter. Increased H2O- and decreased NaHCO3-extractable P with drying provided evidence that drying increases poultry manure P solubility. Labile fractions were predominantly inorganic P (Pi), whereas NaOH- and HCl-fractions had significant amounts of organic P (Po). Drying altered H2O- and NaHCO3-extractable Pi, but had no effect on Po in these fractions. This work suggests that the variations due to drying effects should be taken into consideration when evaluating manures for P availability or when comparing data in which different drying methods have been utilized.