Analysis on the influence of rainfall characteristics on soil and water loss in rocky desertification region

Abstract

To study the influence of rainfall on soil and water loss in karst rocky desertification region, the characteristics and correlations of rainfall, runoff and sediment yield were analyzed under 56 erosive rainfalls from April 2018 to August 2019 in Guanling–Huajiang rocky desertification region of southwestern China. The results showed that the erosive rainfall is mainly rainfall in the study area, and rainstorm’s frequencies and accumulated rainfall were the most in the five erosive rainfalls. Increasing vegetation coverage or reducing bedrock bare rate could effectively reduce the amount of soil and water loss in runoff plots. The rainfall-runoff depth in the runoff plot linearly increased with the increase of rainfall. With the increase of the rainfall kinetic energy, the sediment yield modulus increased approximately linearly, and the relevance of rainfall-sediment yield was weaker than that of rainfall runoff. With the increase of surface runoff, soil loss first increased and then gradually stabilized. The runoff sediment carrying capacity gradually increased with the decrease of vegetation coverage and the increase of bedrock exposure rate. These study results are expected to provide guidance for the control of soil erosion in karst rocky desertification region.