Characteristics of slope runoff and sediment yield on karst hill-slope with different land-use types in northwest Guangxi

Due to shortage of long-term observation data, law of soil and water loss on hillslope is not clear in karst regions of southwest China, which heavily influences the progress of comprehensive control of rock desertification and soil and water loss. Based on five-year observation data from thirteen big runoff plots with projected area more than 1000 m2 (20 m width), surface runoff and soil erosion on dolomite hillslope with different land uses were investigated from 2006 to 2010 in the karst peak-cluster depression area of northwest Guangxi in China. The results showed that annual rainfall varied from 1300 to 2000 mm during the observation periods, and whether in rainy or normal year, event runoff coefficients were less than 5% on hillslope with different land uses, which indicated that surface runoff was very low and all rainwater almost infiltrated into soils on karst hillslope. Surface soil erosion modulus on hillslope had great differences among different land uses, but soil erosion were mostly weak (<30 t/km2·a), and even only 0-5 t/km2·a. Vegetation and land-use types had relatively small effects on surface runoff but human disturbance would increase soil erosion and sediment yield on hillslope. This paper provides a reference for vegetation rehabilitation and soil and water loss control on karst hillslope.