Aspect-induced differences in soil erosion intensity in a gullied hilly region on the Chinese Loess Plateau

摘要

Slope aspect exerts important influence on soil erosion intensity and geomorphologic evolution of land surfaces. Using a digital elevation model (DEM 2 m x 2 m resolution) the gully development intensity in the Wangjiagou catchment on the Chinese Loess Plateau is found to vary as a function of aspect-induced differences in topoclimate. The sunny slopes (i.e., SW, S, and SE aspects) have higher gully erosion intensity than that on the shady slopes (i.e., NE, N, and NW aspects), indicating that south-facing slopes experience faster geomorphic evolution. Variations in process activity can be explained in large part by aspect-induced differences in soil temperature, soil moisture and transpiration, wind force, vegetation coverage and land use pattern on different slope aspects. Lower vegetation coverage and more intensive agricultural activity cause increased erodibility on the sunny slopes. Wind-driven rainstorms can partly explain the higher soil erosion intensity for the sunny slopes, while the impact of mass movement on different slopes is minor. The combination of these factors leads to different soil erosion intensities and geomorphic evolutions on different slopes in the hilly loess region of the Chinese Loess Plateau.