Feasibility of phosphate fertilizer to immobilize cadmium in a field conditions

摘要

Contrary to our expectations, soil Cd extractability and Cd concentrations in radish dry matter increased significantly with increasing fused and superphosphate (FSP) application in the field. To determine the effect of FSP on Cd immobilization, FSP was mixed with the selected soil at a rate of 0, 200, 400, 800, and 1600mg (P)·kg<'-1> and then incubated for 8 weeks. As observed in the field study, exchangeable Cd concentrations increased slightly with a FSP addition of 400mg (P)· kg<'-1> and thereafter significantly decreased with higher application rates. Soil pH and negative charge decreased with 400mg (P)·kg<'- 1> FSP addition and then significantly increased with further increasing application. Based on these results, FSP might be applied at a very high rate (>800mg (P)·kg<'-1>) to decrease Cd extractability in the selected field. The feasibility of FSP to reduce Cd extractability in the field is very low.