Abstract: This paper studied the variation pattern of soil alkaline phosphatase activity and its relationships with soil physical and chemical properties at four different stages of vegetation succession in a typical karst peak-cluster depression of northwest Guangxi, China. Succession stage and soil depth had significant effects on the soil alkaline phosphatase activity, but slope position had less effects. During the succession of original forest- secondary forest, bush forest- grass, and with the increase of soil depth, the soil alkaline phosphatase activity decreased, and had significant difference among different soil layers. The soil alkaline phosphatase activity had significant positive correlations with soil pH and soil organic matter, total N and P, available N, P, and K, silt, and sand contents, and significant negative correlations with soil bulk density and soil total K and clay contents. The canonical correspondence analysis (CCA) showed that succession stage and bare rock rate had primary effects on soil alkaline phosphatase activity, while slope gradient, slope position, and slope direction also had great effects on it.

Key words: Artificial mangroves, Sonneratia apetala, Sonneratia caseolaris, Kandelia candel, Community dynamics, Species-diversities