Abstract:Based on the daily observation data of three runoff communities (tea, mulberry and red taro) in soil and water conservation test station of Huoshan county from 2016 to 2017, this study quantitatively analyzed the law and dynamic changing characteristics of runoff and sediment yield under the conditions of soil moisture content and natural rainfall. The results showed that: (1) April to July was the peak period of runoff, during which the yield of each community accounted for 76% (mulberry), 57% (tea) and 70% (red taro) of the annual yield. The inhibition effect of three crops on the runoff and sediment yield was ranked as tea > mulberry > red taro.(2) The changes of the soil moisture content under different crops were similar, showing a "W" type for the annual change. The average water contents of the surface soil were ranked as tea > mulberry > red taro, which was consistent with the effect of crop inhibition on runoff and sediment yield. The stability of soil moisture was the strongest in autumn and the weakest in summer. Mulberry trees stabilized soil moisture best throughout the year. (3) The grey correlation degrees between rainfall parameters and soil water content were as follows duration > mean rainfall intensity > I30 > I60 > rainfall. Rainfall erosivity had the greatest influence on runoff in crop plots. In terms of sediment yield, the maximum contribution variable of sediment yield in tea land and red taro land was I30, and the maximum contribution variable of sediment yield in mulberry land was rainfall.