Effects of Tillage Erosion on Soil Redistribution in a Purple Soil with Steep Sloping Terraces

This study sought to contribute to the understanding of soil redistribution by tillage erosion, the extent and causes of soil erosion and the contribution of tillage erosion to total soil erosion on the sloping terraces. The total soil erosion derived from caesium-137 (¹³⁷Cs), while tillage erosion was assessed using tillage erosion model within four sloping terraces. Tillage erosion rates were estimated at 77.34, 38.67, 28.84, 24.60 t ha^-1 yr^-1 for Terraces A, B, C, D, respectively, while the total soil erosion rates were 90.93, 52.80, 44.75 and 37.41 t ha^-1 yr^-1 on Terraces A, B, C and D, respectively. The contribution of tillage erosion to the total erosion were 85.05%, 73.23%, 64.43% and 65.75% on Terraces A, B, C, D, respectively, indicating that tillage erosion could be a dominant process of soil erosion. To prove the truth of soil erosion rates derived from tillage erosion model, high resolution digital elevation models (DEMs) were also used to assess tillage erosion rates on the one of sloping terraces. Mean soil flux rate due to tillage erosion which obtained by the DEMs was 25.02 t ha^-1 yr^-1 on Terrace C, suggesting that the tillage erosion models is a reliable method to investigate rates and patterns of tillage erosion on the sloping terraces. This study indicates that tillage erosion redistributes soil in amounts that dwarf the effect of water erosion on the steep sloping terraces. Therefore, the results of our study confirm that tillage erosion is one of the important soil redistribution processes on the sloping terraces.