Response of the winter soil moisture of different vegetation types to rainfall events in karst slope land

Understanding the response of soil moisture of different vegetation types to rainfall in karst regions in winter is significant for implementing various ecological restoration projects. However, at present, the related research is mainly focused on non-winter seasons, and only few research exist on winter seasons. Therefore, in this study, four types of vegetation – grassland, arable land, shrubland, and forestland – were selected as sample plots in the Guanling County of southwestern Guizhou, China. The magnitude, time, and speed responses of soil moisture of the vegetation types to rainfall were calculated using the time-series data of soil moisture of different vegetation types. The results showed that the response of soil moisture differed between different vegetation types in winter and non-winter seasons in karst areas. Among the four vegetation types, soil moisture response magnitude to rainfall in grassland and arable land had a similar distribution pattern along different soil depths, whereas, in scrubland and forestland, it decreased gradually along the soil depth. In addition, compared with other vegetation types, for grassland soil moisture, the response magnitude, response duration, and response speed to rainfall are the largest, longest, and fastest, respectively. Our study used quantitative indices to illustrate the response of soil moisture to rainfall for different vegetation types under a humid climate in a mid-subtropical zone on sloped, pure limestone land. The results of this study provide a scientific basis for the implementation of ecological restoration projects in karst areas.