Phosphate fertilizer addition increases the movement distance and content of the acid soil inorganic phosphorus fractions at green manure microsites

To investigate the movement and content of the acid soil Pi fractions at different distances from the green manure (GM) application site at a GM microsite, an incubation experiment was conducted. Stylosanthes GM (10 or 40 ton/ha) was applied with or without phosphate fertilizer (monocalcium phosphate, MCP) at a concentration of 44 kg/ha P, which was laid on the surface in soil cylinders. The GM/fertilizer and soil were incubated for 14 and 28 d. The results indicated the movement distance and content of the Pi fractions (Al-, Fe-, and Ca-associated Pi as well as occluded P) in the acid soil microsite were significantly increased after the addition of MCP; however, the movement distances of the Pi fractions were all less than 3 mm after incubation for 28 d. This information will improve the efficiency of combined P and GM use and decrease the environmental load due to P pollution caused by GM and phosphate fertilizer.