Study on the phosphorus enrichment and bioavailability in runoff sediments of slope farmland

The enrichment and its bioavailability of phosphorus in runoff sediments were studied by a simulated rainfall experiment and regress analysis. The results showed that runoff sediments had an obvious enrichment effect on phosphorus and its enrichment coefficient (EC) was 1.33~1.43. The inorganic phosphorus was the main phosphours forms in runoff sediments, accounting for 75.23% of total phosphorus (TP). Different binded phosphorus enrichmench and bioavailability was different. Among different forms of phosphorus, phosphorus binded with iron (Fe-P) made the greatest contribution to the content of bioavailable phosphorus in runoff sediments, followed by the organic phosphorus (Org-P).