Response of surface-soil quality to secondary succession in karst areas in Southwest China: Case study on a limestone slope

Abstract

Karst areas are fragile ecological environments facing serious soil quality problems. It is crucial to understand the surface-soil quality for ensuring the secondary succession of vegetation. In this study, four plots located on the same hill slope were selected, representing the four secondary succession stages of arable land, grassland, shrubs, and secondary forest, respectively. The surface-soil quality during secondary succession is assessed using the minimum dataset method. The results show that secondary succession decreased soil bulk density and total potassium content (P < 0.05), whereas soil organic matter, saturated hydraulic conductivity, overall porosity, and total nitrogen increased (P < 0.05). However, pH and capillary porosity are relatively stable. Non-capillary porosity and total phosphorus content first decreased and then increased. In addition, the mean soil quality indices increased and the difference in surface-soil quality between stages decreased with vegetation succession (P < 0.05). Improvement in surface-soil quality is most obvious in the early stages of secondary succession, and natural vegetation restoration can solve the land degradation problem. This study is not only helpful in understanding the changes in surface-soil quality during the secondary succession but also provides a theoretical basis for selecting ecological restoration methods in karst regions.