Soil moisture variations in response to precipitation in different vegetation types: A multi‐year study in the loess hilly region in China

Abstract

AbstractVegetation restoration has been widely implemented as an effective approach to the control of soil erosion. However, severe soil desiccation is likely to occur if vegetation types and local precipitation conditions are not accounted for. In this study, an abandoned farmland and three typical vegetation types, including a natural shrubland, a plantation of black locust, and a natural oak secondary forest, were investigated to determine the characteristics of soil moisture in different hydrological years. The responses of soil moisture to precipitation were analysed at different timescales. Higher soil water contents were observed either in wet years or for natural vegetation types. The temporal response of soil moisture to precipitation was largely dependent on the timescale. At monthly scale, shallow soil moisture (0–100 cm) varied consistently with precipitation, whereas on interannual scale, precipitation is positively related to soil moisture along the whole profiles. Black locust and oak lands consumed more soil moisture than the shrubland, and severe soil desiccation developed in deep soil layers in the black locust plantation. The shrubland showed steeper regression slopes than other types for both the changes in soil water storage over time (ΔSWSt) versus the growing season precipitation and the difference in soil water storage with the abandoned farmland (ΔSWSv) versus the growing season precipitation, suggesting its higher adaptability to precipitation changes in this region. The results indicate that the shrubland develops optimal water use strategies through coevolution with local conditions and should be given precedence in vegetation restoration initiatives in this region.