The relative contributions of slope gradient and vegetation cover on erosion characteristics of riparian slopes along the lower Yellow River, China

Abstract

Slope gradient and vegetation cover play key roles in soil erosion process. Exploring the effects of slope gradient and vegetation cover on runoff and sediment yielding characteristics is therefore of great importance for minimizing soil erosion. In this work, based on field scouring experiments on the riparian slopes of the lower Yellow River, China, variation in total runoff, accumulative runoff sediment concentration, erosion sediment yield, and sediment particle size composition under four slope gradients (5°, 10°, 15°, 20°) and three vegetation cover levels (0%, 15%, 30%) were analyzed. Runoff and sediment yield were greatly influenced by slope gradient at steep slope gradients (15° and 20°), while they were mainly affected by vegetation cover at medium slope gradients (5° and 10°). The main enriched particle size of the eroded sediment showed a trend of first increasing and then decreasing with the increasing slope gradient. There was an interaction between slope gradient and vegetation cover, the effect of vegetation cover on erosion sediment yield weakened gradually with increasing slope gradient (at medium slope gradients of 5° and 10°), while the effect of slope gradient increased at steep slope gradients (15° and 20°).