Effect of phosphate fertilizer and manure on properties of phosphorus sorption and desorption in soils with different phosphorus levels

The effect of phosphate fertilizer and manure on properties of phosphorus sorption and desorption was studied on soils with different phosphorus levels. Parameters of sorption and desorption were obtained from Langmuir isotherm by incubating experiment. The results showed that maximum P sorption (Qm) and max buffering capacity (MBC) of soil phosphorus were decreased while readily desorbable phosphorus (RDP) increased with the increase of soil phosphorus levels. Qm and MBC of phosphorus in soil were decreased while readily desorbable phosphorus and desorption ratio were increased in soils after applying phosphate fertilizer and manure. Olsen-P had positive correlation with readily desorbable phosphorus and desorption ratio, but negative correlation with Qm and MBC. The main conclusions were that readily desorbable phosphorus could be increased by increasing phosphate fertilizer or soil phosphorus levels. The MBC of soil phosphorus was decreased while phosphorus desorption rate increased with increasing rate of phosphate fertilizer and manure. The Qm and MBC were mainly effected by soil phosphorus levels and application rate of P.