Effects of vegetation on the distribution of soil water in gully edges in a semi-arid region

Abstract

Gully bank is an important part of the eroded gully and is an ecologically fragile zone. Vegetation and soil water play critical roles for regulating the hydrological process of gully banks and preventing the soil collapse of gully edge in arid and semi-arid areas. However, the effects of different vegetation on the distribution of soil water in the gully edge are still unknown in semi-arid areas. In this study, the variation in soil water content (SWC) was studied at distances of 0.5 m (D0.5), 2.0 m (D2.0), and 3.5 m (D3.5) from the gully edge in a shrubland (SL), bare land after removal of shrubs (SBL), grassland (GL), and bare land after removal of grasses (GBL). The results showed that SWC reduced with proximity to the gully edge in SBL and GBL. Soil water storage in both SL and GL was higher at D0.5 than at D2.0 and D3.5. In both dry and wet seasons, SWC in SL was significantly lower than that in GL at all locations (P < 0.05). Compared with SBL, the SWC in SL in the wet season significantly reduced 15.42%, 27.56%, and 27.73% at D0.5, D2.0, and D3.5, respectively (P < 0.05). Our findings suggest that grasses should be considered as a suitable choice for revegetation in gully banks to prevent excessive soil water depletion by shrubs and reduce the risk of soil collapse in the gully edge. These findings provide insights into the effects of different vegetation types on soil hydrological processes in gully edges.