Catena   2015 年 129 卷

2015.06.01

Secondary forests with little understory vegetation and litter accumulation are facing a serious threat of erosion in the red soil region of southern China. To quantify the soil loss and develop prediction equations, 30 field rainfall simulation experiments were conducted with two rainfall intensities and five slope gradients in a 20-year-old Pinus massoniana forest. The results show that under the higher rainfall intensity, the runoff generation from the forest floor was high, even on gentle slopes. During simulated rainstorms, the initial soil losses increased rapidly and reached the peak value nearly at the same time as the peak runoff. Then soil loss decreased and runoff leveled out. Soil losses were significantly correlated with rainfall intensity, slope steepness and runoff rate. Further regression between soil loss as a dependent variable and runoff coefficient on different slopes verified that there exist interactions between slope and runoff factors in affecting soil loss. Stream power, which reflects the effect of both slope steepness and runoff rate can provide a more precise estimation (R