Vegetation variation regulates soil moisture sensitivity to climate change on the Loess Plateau

Soil moisture is a key component of global hydrological cycles and is closely linked to climate and vegetation. However, exactly how vegetation affects the response of soil moisture to climate remains unclear. In this study, soil moisture sensitivity was investigated as an indicator of soil moisture response to climate change (including temperature and precipitation). Twenty years of data from the GLEAM (Global Land Evaporation Amsterdam Model), meteorological station, and remote sensing of the Loess Plateau of China were used to estimate the impact of the vegetation regulatory action on soil moisture sensitivity. The results show that soil moisture sensitivity to both temperature and precipitation exhibits distinct spatiotemporal patterns. With increasing Enhanced Vegetation Index (EVI), soil moisture sensitivity to temperature decreased at first and increased subsequently, while that to precipitation decreased continuously, reaching a stable value. The overall level of soil moisture sensitivity to both temperature and precipitation in the Loess Plateau was declining. Specifically, vegetation variation contributed 23.78% and −78.57% of the soil moisture sensitivity to precipitation in the surface and root zone, respectively, which is higher than it contributed to the soil moisture sensitivity to temperature (11.4% and 17.23%). The results of this study provide a scientific basis for the effective implementation of the 'Grain for Green' Program and the sustainable management of water resources on the Loess Plateau.