Evolutionary characteristics and main influencing factors of loess erosion in Xindiangou small watershed based on watershed geomorphic entropy

The geomorphic evolution of the Xindiangou small watershed on the Loess Plateau in China is influenced by many factors, resulting in very complex evolutionary characteristics of erosion, morphology, and development. Since 1952, a number of soil and water conservation projects have been implemented in the watershed, especially the large-scale project of returning farmland to forest and grass since 1999, which has significant impact on the erosion characteristics of the loess. This paper takes a unique perspective of the watershed geomorphic system and its watershed geomorphic entropy (WGE) and clarifies the geomorphic erosion characteristics of the Xindiangou small watershed. The results show that in the past 45 years, the entropy change of WGE of this watershed has generally shown the characteristics of entropy decrease and local entropy increase. The watershed is dominated by erosion in general, but due to the large-scale implementation of various soil and water conservation projects, especially the Project of Returning Farmland to Forests and Grasslands (RFFG), the landform erosion intensity has been greatly reduced and local increase in the entropy change of WGE has appeared. These projects have achieved good ecological effects after 11 years of implementation.