Abstract:

The variation of soil enzyme activities under a Karst forest was studied by comparing soil enzyme activity and soil nutrient content under different vegetation types and different ages of Zanthoxylum planispinum var. dingtanensis forest in Beipan River Karst gorge district. The Z. planispinum var. dingtanensis forest was the phase of the forest succession. The results indicated that, with increase of degradation intensity, the soil enzyme activity declined. The soil enzyme activity was in an order of forest>shrubbery(Z. planispinum var. dingtanensis forest)>bush>grassland. The soil enzyme activity declined obviously in the process of degradation. The soil enzyme activity of sucrase, amylase, proteinase, urease, phosphates, polyphen oxidase in the forest was higher than bush and grassland's. The Z. planispinum var. dingtanensis forest was on the mid of this process. Fertilization was able to stave off the soil's degeneration in short time. However the long-term effect of fertilization needs to be inspected.

Key words: soil enzyme activity, vegetation types, Karst, Beipang River