U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska


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Published in Communications in Soil Science and Plant Analysis, 38: 1879–1895, 2007. DOI: 10.1080/00103620701435639


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