Effects of different terrace protection measures in a sloping land consolidation project targeting soil erosion at the slope scale

Abstract

Land consolidation of sloped areas using terrace construction is undertaken to improve water conservation, control soil erosion and enhance soil fertility. The subsequent soil and water conservation effects of this practice have received much attention. Quantitatively analyzing the effects of protective measures on soil erosion will have significant practical applications. In this study, changes in soil and water conservation were compared under 64 scenarios of varying terrace protection measures (coverage series) and six configurations (high, medium and low grass coverage combinations). These scenarios were simulated using the process-based soil erosion WEPP model and considered the physical constraints and conditions of typical land consolidation projects. Results showed large differences in soil loss and sediment yield in scenarios of different grassland coverage. Sediment yield was found to have a strong correlation with rainfall intensity. Compared to unstructured slopes, the sediment trapping rate of terraced slopes increased with grassland coverage but negligible variation was found with change in rainfall intensity. The results of different spatial configuration scenarios of high, medium and low grass coverage indicated that protective measures worked best when located at the lowest position along slopes.