Effects of Distributions of Grass Strips on Soil Erosion in Spoil Tips

The spatial distribution pattern of vegetation is of great significance to the prevention and control of soil erosion in spoil tips. The objective of this study was to evaluate the effects of spatial distributions of grass strips on soil erosion in spoil tips. A field runoff plot (20 m long, 1 m wide, and 0.5 m deep) was used for inflow simulation experiments under four inflow rate patterns (even, rising, falling, and rising-falling) and five grass strip patterns (patterns I-V). Results showed that the runoff reduction benefit (RRB) and soil loss reduction benefit (SLRB) of grass strip patterns were 12.23-49.62% and 12.92-80.54%, respectively. The optimal grass strip pattern was when the grass strips were distributed on a slope in bands (pattern V). In this pattern, the soil and water conservation effects were best, with RRB and SLRB of 43.87% and 58.09%, respectively. The grass strip patterns exhibited a significant time-limited effect on controlling soil erosion. The maximum amount of soil loss reduction for patterns II, III, IV, and V was 93.02, 84.30, 65.86, and 98.26 kg, respectively. Soil loss reduction caused by decreasing runoff (SRR) for grass strip patterns was the main factor controlling erosion. The efficiency coefficient of soil loss reduction caused by decreasing runoff for pattern V was higher than that for the other patterns. The grass strip pattern V (i.e., grass strips were distributed on a slope in bands) should be considered a priority in the prevention of soil erosion in spoil tips. This study can guide the configuration of vegetation control measures for soil and water loss in spoil tips.