Characteristics of Phosphorus Runoff Losses and Influencing Factors in Three Cultivated Soils

Black soil, fluvo-aquic soil and red soil were the main cultivated soil types in China. A simulated rainfall experiment was conducted to study the effects of different rainfall intensity and phosphorus levels on phosphorus concentration and loss in the above-mentioned 3 kinds of soil types. The results show that:(1)The TP content in black soil, fluvo-aquic soil and red soil runoff ranged from 0.143 to 1.220 mg·L^-1, and the TDP content ranged from 0.035 to 0.474 mg·L^-1. The TP and TDP concentrations in different soil types were in the order of fluvo-aquic soil > red soil > black soil.(2) The concentration of phosphorus in runoff mainly depended on the content of available phosphorus in the surface soil. There was an exponential relationship between TP loss and soil phosphorus level. (3) The concentrations of TP and TDP in black soil, fluvo-aquic soil and red soil runoff increased with the rainfall intensity. There was a linear relationship between total phosphorus loss and rainfall intensity in different soil runoff. The linear relationship of fluvo-aquic soil was the best, followed by black soil and red soil. (4) The main form of phosphorus loss from surface runoff was granular.