[Responses of runoff and soil loss from biological soil crustal slope to rainfall intensity under simulated rainfall]

Biological soil crust (biocrust) is a common surface cover on the rehabilitated slope land in Hill Loess Plateau. We investigated the responses of runoff and soil loss from biological soil crustal slope to rainfall intensity by using simulated rainfall trial. The results showed that the runoff and soil loss from biocrust slopes increased sharply at the beginning stage of rainfall and then became stable during 10 to 18 min. Compared to bare soil slope, the initial runoff generation time of biological soil crustal slope was significantly increased. The presence of biocrust could significantly decrease runoff and sediment by 21%-78% and 77%-95%, respectively. Rainfall intensities affected soil erosion of biocrust slopes mainly via affecting runoff. The transition from insignificant to significant correlation between runoff and soil loss from biological soil crustal slopes and rainfall intensities was observed with the increases of rainfall intensities. Once the rainfall intensity was higher than 1.5 mm·min^-1, there was a significant decrease in the function of biocrust to decrease runoff and soil loss with the increases of rainfall intensities. Our results laid the foundation for the model simulation of runoff and soil loss from biocrust slopes under rainfall conditions.