Effects of ryegrass canopy and roots on the distribution characteristics of eroded sediment particles during heavy rainfall events on steep loess‐cinnamon slopes in Zhangjiakou, China

Abstract

AbstractTo evaluate the effects of ryegrass (Lolium perenne) canopy and roots on eroded sediment particle distribution characteristics, simulated rainfall tests were implemented on grass caopy, roots, and bare slopes. The grass coverage density were 0, 20, 40, and 60%. The results showed that ryegrass canopies mainly contributed to runoff reduction and ryegrass roots primarily contributed to erosion reduction. With increasing rainfall duration, smaller particles (clay and fine silt particles) increased and larger particles (coarse silt and sand particles) decreased in the eroded sediment on the grass slope while the opposite trend was observed for the roots and bare slopes. Moreover, the clay and sand particles were eroded as aggregates and most silt particles were transported in the form of primary particles. Compared to the original soil, larger particles in the eroded sediment mainly occurred on the grass slopes because smaller particles were intercepted by the grass canopies, while smaller particles primarily occurred in the eroded sediment of the root slopes because grass roots inhibited soil erosion. These results illustrate that grass cover can prevent the loss of small particles in the topsoil and avoid soil coarsening, which provides guidance for the comprehensive control of soil erosion.