Abstract:
With the continued development of ecological civilization on the Loess Plateau, cultivated land on the very gentle slopes has become the most significant area affected by local production activities, its soil erosion should be paid enough attention.Based on this, indoor simulated rainfall test is adopted to study the sheet erosion characteristics and the variation rules of hydrodynamic parameters of the two soils (Ansai soil and Suide soil) under the condition of 90 mm/h rainfall intensity, two slopes (2.5° and 5°) and two slope lengths (5 m and 10 m). The results show that, compared with the Ansai soil, the Suide soil has a shorter runoff production time, a faster runoff increasing rate, a higher runoff with sediment content, and is prone to rill erosion. The average runoff and sediment content of Ansai soil ranged from 2.76 to 8.61 L/min and 0.80 to 9.26 g/L before runoff stabilization, and from 3.76 to 11.69 L/min and 0.46 to 2.88 g/L after runoff stabilization. The average runoff and sediment content of Suide soil before and after runoff stabilization was 3.94 to 12.75 L/min, 2.13 to 10.64 g/L and 4.51 to 15.02 L/min, 1.20 to 4.51 g/L, respectively. The relationship between sediment content and runoff can be characterized by a linear descent function with sediment content as a constant. In contrast, the Reynolds number and runoff power increase linearly with runoff with a clear and stable behavior. The runoff velocity and Froude number show a clear trend of increasing with runoff, but the fluctuations are large. The runoff shear force shows a large dispersion with runoff. Overall, for sheet erosion, Reynolds number and runoff power are the most suitable hydrodynamic parameters to characterize soil erosion, followed by runoff velocity and Froude number, and runoff shear force. The above results can provide a theoretical reference for optimizing soil erosion model parameters.
