Impacts of changes in vegetation on saturated hydraulic conductivity of soil in subtropical forests

Saturated hydraulic conductivity (K-s) is one of the most important soil properties that determines water flow behavior in terrestrial ecosystems. However, the K-s of forest soils is difficult to predict due to multiple interactions, such as anthropological and geomorphic processes. In this study, we examined the impacts of vegetation type on K-s and associated mechanisms. We found that K-s differed with vegetation type and soil depth, and the impact of vegetation type on K-s was dependent on soil depth. K-s did not differ among vegetation types at soil depths of 0-10 and 20-30 cm, but was significantly lower in managed forest types (mixed evergreen broad-leaved and coniferous forests, bamboo forests, and tea gardens) than native evergreen broadleaf forests at a depth of 10-20 cm. Boosted regression tree analysis indicated that total porosity, non-capillary porosity, and macro water-stable aggregates were the primary factors that influenced K-s. Our results suggested that vegetation type was a key factor that influences hydraulic properties in subtropical forest soils through the alteration of soil properties, such as porosity and macro water-stable aggregates.