Effects of the Gully Land Consolidation Project on soil erosion and sediment yield on the Loess Plateau, China

Land consolidation can increase the area of arable land and improve the ecology and environment and is widely used worldwide. The Gully Land Consolidation (GLC), as a special type of land consolidation, significantly impacts soil erosion. The purpose of this study was to investigate the effect of the GLC on soil erosion and sediment yield under different rainfall events and hydrological years in the Xingshuyaozi watershed on the Chinese Loess Plateau, where the GLC area accounted for 10.36% of the watershed. A computer model integrated with the Chinese soil loss equation (CSLE) and the continuity equation of sediment was used. Sediment connectivity before and after the GLC was compared to illustrate the effect of the GLC on sediment yield. The results showed that the reduction in soil loss increased with increasing rainfall amount, and the reduction rate of soil erosion was over 50%. The GLC had the greatest effect on soil erosion in wet years. The GLC effectively decreased sediment at the outlet of the watershed, with over 99% of the sediment being trapped. The reduction efficiency of soil erosion and sediment yield decreased in order of wet year, normal year and dry year. The decreased soil erosion and sediment yield resulted from the significantly lowered slope gradients and sediment connectivity after the GLC. These results indicate that the GLC is an effective soil and water conservation measure. These results can provide technical support for the application of the GLC and policymaking.