Soil nutrient variation impacted by ecological restoration in the different lithological karst area, Shibing, China

Abstract

To carry out differentiated ecological restoration activities and formulate appropriate environmental conservation strategies for karst regions with different underlying bedrocks, it is essential to investigate the impact of ecological restoration and lithological differences on soil nutrients. The Karst world heritage site in Shibing, Guizhou province, China was selected as the study site. Here, we determined pH and nutrient differences in soil profiles of dolomite and limestone areas with ecological restoration activities. The results showed that (1) the main controlling factors of the topsoil were different from those of the core and bottom soils. (2) The topsoil was more sensitive to ecological restoration. Soil organic carbon, total nitrogen, and available nitrogen contents in the topsoil samples from the post-agricultural succession areas were significantly higher than those in the cultivated areas (P < 0.05), and were at 2.04–3.99, 1.62–4.07, and 1.52–3.18 -fold, respectively. (3) The core and bottom soils were mainly affected by the differentiated dissolution between the dolomite and limestone areas. The available nitrogen in the core and bottom soils were significantly lower in the dolomite area than in the limestone area (P < 0.05), and were 76.5% and 40.8% lower, respectively. Total phosphorus, available phosphorus and pH in the bottom soil were significantly higher in the dolomite area than in the limestone area (P < 0.05), and were 1.12, 1.86, and 2.63-fold, respectively. (4) Shrub recovery played a major role in the rapid accumulation of soil carbon and nitrogen in the dolomite area. Consequently, shrub development is very critical in the early stages of ecological restoration of dolomite areas following agricultural abandonment.