COUPLING RELATIONSHIPS BETWEEN PLANT COMMUNITY AND SOIL CHARACTERISTICS IN CANYON KARST REGION IN SOUTH-WEST CHINA

Plant community characteristics in Canyon Karst region in southwest China and analyze the coupling relationships between plant communities and soil properties in different ecosystems have been explored. Eighteen plots (20 x 20 m) in six ecosystems (paddy field, dry land, grassland, shrubbery, artificial forest, and secondary forest) in canyon karst region in south-west China are established. The species composition and diversity characteristics of above mentioned ecosystems were investigated. To find the relationships between vegetation and soil properties, principal component analysis (PCA) and canonical correlation analysis (CCA) were carried out. Forty indices of plant communities and soil properties were chosen. The results showed that with the development of vegetation community succession, species diversity value of the herb layer was larger than that of the shrub. The maximum value of species diversity mainly appeared in the secondary forest. The Canyon Karst Region had high landscape heterogeneity, and different ecosystems had different dominant factors. Species diversity was the dominant factor in karst fragile ecosystems, followed soil microbes and large particle aggregate organic carbon. CCA elucidated a close relationship between species diversity and soil properties (organic carbon, total nitrogen (total P), available nitrogen, Al2O3, Fe2O3, bacteria, actinomycetes and soil microbial diversity). Thus, in vegetation improvement and management practices, it is necessary to consider the heterogeneity of each factor as well as the relationship between vegetation and soil factors.