Characterization of phosphorus in fresh and composted manures of different livestock

Abstract

The characterization of phosphorous (P) from animal manure is important for sustainable nutrient management. P fractions in fresh and composted animal manure was compared for the release of phosphorous fraction to determine heavy metals (Fe, Zn, Mn, Ni, and Hg). Composted and fresh animal manure were collected from four different sources: buffalo (BF), cow (CW), goat (GT), and poultry (PL). The P fraction was determined by using the Hadley sequential fractionation method. The P was step-wise fractionated into water-soluble extracted P (H2O-P), plant available (NaHCO3-P), Al associated (NaOH-P), and Ca associated (HCl-P). The overall P fractions extracted by reagents varied in the order HCl > NaOH > NaHCO3 > H2O. The metal concentration varied as follows: Fe > Hg > Mn > Zn > Ni. The highest P content was found in composted PL manure whereas the minimum was observed in fresh PL. Consequently, the composed animal manure could be an economical P source to be used as fertilizer.