Improvements in soil quality with vegetation succession in subtropical China karst.

Abstract

Secondary vegetation succession can alter soil functions and quality. However, data on changes to soil quality at different stages of vegetation succession in karst areas of southwest China is limited. This study aimed to evaluate the effects of different vegetation succession on soil quality and further to identify the factors that influencing soil quality. Secondary forest, shrub, grass, and cropland (as a reference) were selected and sampled in the subtropical karst of southwest China. Soil quality index (SQI) was developed by two methods of Total Data Set (TDS) and Minimum Data Set (MDS). Based on principal component analysis (PCA), soil organic carbon, silt, available phosphorous, available potassium, soil thickness, and soil water content were identified as the most representative indicators for the MDS. Both methods showed that the highest SQI values were observed in secondary forest, followed by shrub and grass, and the cropland values were the lowest. This showed vegetation succession significantly influenced on soil physiochemical properties and thus on soil quality. MDS could adequately represent TDS to quantify the effects of vegetation succession on soil quality since similar SQI results were derived from the two methods (R2\xa0=\xa00.68, P\xa0<\xa00.01). The influencing factors explained about 75% of the total variation in SQI using a generalized linear model. Vegetation types accounted for the largest proportion of the SQI variability followed by restoration time, indicating these factors significantly affect soil quality during vegetation succession. In general, vegetation succession significantly influenced soil properties, and also has long-term and positive effects on soil quality during vegetation restoration. This study helps to understand the changes in soil quality during vegetation succession and provides guidance for the sustainable management of revegetation in subtropical karst regions in China.