Effect of Grass Cover on the Change of Overland Flow Energy in the Slope-gully Side Erosion System

摘要

It' s significant for understanding the soil loss reducing mechanism of grass cover to study the changeable process and characteristics of overland flow energy with different grass cover and spatial distributions in the slope-gully side erosion system. The objective of this study is to reveal preliminarily the laws of spatial and temporal distribution of rill flow energy in the slope-gully side erosion system under grass cover by scouring experiments. Five grass cover degrees, three spatial locations of grass and two water inflow rates were applied to a 0.5 by 8 m soil bed in scouring experiments. Results showed that both the potential energy and kinetic energy are smaller for the hillslope with grass cover, and the variation is smoother than that without grass cover. During the scouring experiments, the consumption of runoff energy on all different segments on the sloping surface reduced first and then kept stable, and it increased significantly with increasing downslope distance. It' s practical to disclose the soil loss reducing mechanism of grass by analyzing the variance of overland flow energy.