Phosphorus loss with runoff from a side bleaching paddy soil under continual P application in Taihu Lake Region

A field experiment was conducted to estimate quantitatively P loss from rice fields applied with different rates of P fertilizer.The ground parts of the crop removed about 47.5 kg·hm^-2 P from the paddy field.The quantities of P loss with runoff and the amounts of P enrichment in the （0-10） cm surface soil were linearly related to the rates of P application.The loss of total P with runoff ranged from 1.3 to 5.1 kg·hm^-2 and increased with the P application rate.It could be concluded that although excessive P application would increase the risk of P loss with runoff from the paddy field,the amount of P loss in the side bleaching paddy soil was low at the present local P application rate,and that the application rate of 50 kg·hm^-2 P during the rice growth season in the side bleaching paddy soil was acceptable.