Assessment of the impact of different vegetation patterns on soil erosion processes on semiarid loess slopes: Effect of vegetation patterns on runoff and soil erosion on loess slopes

Soil erosion hinders the recovery and development of ecosystems in semiarid regions. Rainstorms, coupled with the absence of vegetation and improper land management, are important causes of soil erosion in such areas. Greater effort should be made to quantify the initial erosion processes and try to find better solutions for soil and water conservation. In this research, 54 rainfall simulations were performed to assess the impacts of vegetation patterns on soil erosion in a semiarid area of the Loess Plateau, China. Three rainfall intensities (15mmh(-1), 30mmh(-1) and 60mmh(-1)) and six vegetation patterns (arbors-shrubs-grass -A-S-G-, arbors-grass-shrubs -A-G-S-, shrubs-arbors-grass -S-A-G-, shrubs-grass-arbors -S-G-A-, grass-shrubs-arbors -G-S-A- and grass-arbors-shrubs -G-A-S-) were examined at different slope positions (summits, backslopes and footslopes) in the plots (33.3%, 33.3%, 33.3%), respectively. Results showed that the response of soil erosion to rainfall intensity differed under different vegetation patterns. On average, increasing rainfall intensity by 2 to 4 times induced increases of 3.1 to 12.5 times in total runoff and 6.9 to 46.4 times in total sediment yield, respectively. Moreover, if total biomass was held constant across the slope, the patterns of A-G-S and A-S-G (planting arbor at the summit position) had the highest runoff (18.34Lm(-2)h(-1)) and soil losses (197.98gm(-2)h(-1)), while S-A-G had the lowest runoff (5.51Lm(-2)h(-1)) and soil loss (21.77gm(-2)h(-1)). As indicated by redundancy analysis (RDA) and Pearson correlation results, a greater volume of vegetation located on the back- and footslopes acted as effective buffers to prevent runoff generation and sediment yield. Our findings indicated that adjusting vegetation position along slopes can be a crucial tool to control water erosion and benefit ecosystem restoration on the Loess Plateau and other similar regions of the world. Copyright (c) 2018 John Wiley & Sons, Ltd.