EGU21-9872, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-9872
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Experimental study on dynamic mechanism of sheet erosion processes on steep grassland in the loess region of China

Qi Guo1,3 and Zhanli Wang1,2
Qi Guo and Zhanli Wang
  • 1State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China
  • 2State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China
  • 3University of Chinese Academy of Sciences, Beijing, China

Sheet erosion has been the major erosion process on steep grassland since the Grain-for-Green project was implemented in 1999 in the Loess Plateau with serious soil erosion, in China. Quantifying sheet erosion rate on steep grassland could improve soil erosion estimation on loess hillslopes and provide scientific support for effectively controlling soil erosion and rationally managing grassland. Simulated rainfall experiments were conducted on grassland plot with vegetation coverage of 40% under complete combination of rainfall intensities of 0.7, 1.0, 1.5, 2.0 and 2.5 mm min-1 and slope gradients of 7°, 10°, 15°, 20° and 25°. Results showed that sheet erosion rate (SE), varying from 0.0048 to 0.0578 kg m-2 min-1, was well described by binary power function equation (SE = 0.0026 I1.306S0.662) containing rainfall intensity and slope gradient with R2 = 0.940. The logarithmic equation of shear stress (SE = 0.084 + Ln (τ)) and the power function equation of stream power (SE = 1.141 ɷ1.073) could be used to predict sheet erosion rate. Stream power (R2 = 0.903) was a better predictor of sheet erosion than shear stress (R2 = 0.882). However, predictions based on flow velocity, unit stream power, and unit energy were unsatisfactory. The stream power was an excellent hydrodynamic parameter for predicting sheet erosion rate. The sheet erosion process of grassland slope was also affected by the raindrop impact except the dynamic action of sheet flow. The combination of stream power and rainfall kinetic energy (KE) among different rainfall physical parameters had the most closely relationship with the sheet erosion rates, which is also better than the stream power only, and a binary power function equation (SE = 0.221 ω0.831KE0.416) could be used to predict sheet erosion rate on grassland slope with R2 = 0.930. The study results revealed the dynamic mechanism of the sheet erosion process on steep grassland in the loess region of China.

How to cite: Guo, Q. and Wang, Z.: Experimental study on dynamic mechanism of sheet erosion processes on steep grassland in the loess region of China, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9872, https://doi.org/10.5194/egusphere-egu21-9872, 2021.