Effects of soil surface roughness on sheet erosion and change under different rainfall conditions

To further determine the effects of soil surface roughness on sheet erosion, changes of soil surface roughness were obtained under the single and continuous rainfall intensities based on the artificial rainfall simulation experiments. The results showed that under the rainfall intensity of 0.67 mm/min, the runoff amount and sediment yield of each slope decreased firstly, and then the stable change with the increasing soil surface roughness. Soil surface roughness declined for other artificial management practices except for hoeing cropland, opposite to the changes of contrast slope. Under the rainfall intensity of 1.63 mm/min, the runoff amount and sediment yield of each slope decreased with the increasing soil surface roughness. Soil surface roughness decreased for the slope of digging cropland and contour tillage, consistent to the changes of contrast slope. While soil surface roughness increased for the slope of hoeing cropland and raking cropland, opposite to the changes of contrast slope. Under the continuous rainfall intensity, the runoff amount and sediment yield of artificial management practices decreased gradually with the increasing soil surface roughness, and were lower than those of the contrast slope at the first and second rainfall. The changes of runoff amount and sediment yield were comparatively complex, and sediment yields of the slope with artificial management practices were higher than those of contrast slope at the third rainfall. The results will provide theory basis for posing the erosion nature of roughness, and at the same time, it will serve for harnessing soil and water loss of the slope farmland in Loess Plateau.