Effects of parent material on soil hydraulic properties in subtropical hilly area of Southern China

Abstract

The parent materials play an important role in soil hydrologic properties. However, in subtropical hilly areas with complex geological conditions, it appears that there is a lack of full understanding about the effect of parent material on soil water-holding and erosion resistance, which can be helpful for agricultural production and conservation of soil and water. In this study, five red soils developed from shale (Ds), quartz sandstone (Dqs), argillaceous nodular limestone (Danl), argillaceous limestone (Dal), and limestone conglomerate (Dlc) in subtropical China were selected. Soil properties, soil water-retention curves (SWRCs), water-stable aggregate fractions, and soil erodibility factor (K) were tested and calculated. The results showed that there are significant differences in soil texture among soils developed from different parent materials, soils with higher clay content have stronger water-holding capacity, and the average water-holding capacity of the five soils followed the order Dal > Danl > Ds > Dlc > Dqs. Furthermore, the erosion resistance of soil is closely related to the clay content and the stability of soil aggregates, and the sequence of average K-value among the five soil types is as follows: Danl > Dal > Dlc > Ds > Dqs. Partial least squares regression revealed that the stability of aggregates has a more significant influence on soil erodibility than the clay content. Therefore, soils with higher mean weight diameter (MWD) and geometric mean diameter (GMD) are more resistance to erosion. This paper evaluated the distinctions in basic properties and hydraulic properties between different parent materials under similar climatic conditions, elevations and vegetation in subtropical hilly area of Southern China, which can serve as a scientific foundation for soil and water conservation in the environments characterized by complex geological conditions.