Coupling relationship between vegetation and soil in the early stage of ecological restoration after earthquake: a case study of Weizhou Town in Wenchuan County and Hanwang Town in Mianzhu City of Sichuan Province, southwestern China

  Objective  Studying the coupling and coordination relationship between vegetation and soil in the early stage of restoration in different climate regions of the Wenchuan earthquake-affected areas can provide a basis for promoting the ecological restoration and the coordinated development of vegetation-soil system in the disaster disturbed area.

  Method  In this study, the treated area and undestroyed area of the arid-valley climate region and the subtropical monsoon climate region (AT and AU, ST and SU) were selected as the research objects. We measured twenty-one indexes covering plant and soil, analyzed the main influencing factors and the weights of twenty-one indicators of the four ecosystems in the two climate regions by principal component analysis, and constructed the corresponding model of vegetation-soil coupling coordination degree.

  Result  SU’s D, comprehensive indexes of vegetation and soil were all significantly higher than the other three vegetation-soil systems. AT and ST were both soil lagging development type of primary coordinated development, AU and SU were synchronous development type of vegetation and soil of primary and intermediate-level coordinated development, respectively. The influencing factors of the arid-valley climate region were relatively simple: the main influencing factors of AT were soil organic carbon, total nitrogen, available nitrogen and available phosphorus, and those of AU were plant carbon, nitrogen, potassium and magnesium. The influencing factors of the subtropical monsoon climate region were vegetation-soil influencing factors coexisting: the main influencing factors of ST were species richness, biomass, soil total nitrogen and available nitrogen, and those of SU were vegetation coverage, plant phosphorus, soil available potassium and bacteria.

  Conclusion  The climate and type of ecological restoration had certain influence on the coupling status of vegetation and soil. The coupling status of vegetation-soil in SU was significantly better than the other three ecosystems. The soil environments of AT and ST were both poor, indicating that nutrient condition of treated areas did not recover to the pre-earthquake level after treatment for seven years.