Transfer and accumulation of phosphorus in the calcareous purple soil in a long-term fertilizer experiment

Experiments of transport and accumulation of phosphorus in soils was conducted in order to find effective ways to manage and control phosphorus and non-point pollution in crop fields. Different fertilizations were treated in calcareous purple soils in a 25-year rice-wheat rotation field. Factors, such as total phosphours in the soil profile, transport and accumulation of Olsen phosphours (Olsen p), and patterns change over time, were studied. Results showed in the soil, phosphorus was detected at 100 cm, and Olsen p was at 40 cm down to the ground. The application of organic or inorganic P not only increase the depth of P detected in the ground, but also the quantity of P measured in the ground. Meanwhile, Olsen-p was also detected at 60 cm down to the ground with the application of organic or inorganic P treatment. After 25 years treatment, the annual accumulation rate in the plough layer was measured as 0.033 g/kg for total P, and 2.56 mg/kg for Olsen-P for the MNPK treatment. The result suggests that P application rates should be reduced accordingly in order to save the amount of phosphate fertilizer used and to increase the efficiency in the crop field.