The effects of three micro-catchment practices on erosion and runoff dynamics for a typical soil slope on the Loess Plateau of China

摘要

Three micro-catchment measures that are named fish-scale pits (FSPs), artificial digging (AD), and contour plowing (CP) for soil erosion prevention are widely used in the Loess Plateau. To clarify the effectiveness of these measures in intercepting runoff and reducing erosion and the mechanism of water flow movement, intermittent simulated rainfall events was carried out in the 15 degrees slopes with FSPs, AD, CP, and control slope (CK). The results demonstrated the following. (1) For cumulative rainfall &83 mm, three measures effectively intercepted runoff and reduced sediment compared with the CK. The runoff and sediment reduction effect of three measures gradually disappeared when cumulative rainfall increased to 83, 99, and 108 mm, and the sediment generation of the three measures successively exceeded that of the CK and was more than two times higher. (2) Laminar or transition flow occurred for the CK, and the flow pattern changed from subcritical to supercritical at 101 mm of cumulative rainfall. For three measures, the flow patterns became turbulent within a short time but remained subcritical. (3) A correlation analysis showed that the soil detachment rate, hydraulic shear stress, and stream power in the micro-catchment measures can be described using linear functions, which reduced the rill erodibility and enhanced the soil's resistance to concentrated flow erosion. This research has important guiding significance on the rational and effective implementation of micro-catchment practices to prevent severe soil erosion and increase water storage for crop production on the Loess Plateau of China.