Path analysis of soil enzyme activity and soil properties of Chinese fir plantations.

The Chinese fir (Cunninghamia lanceolata) plantations in Dagang Mountain of Jiangxi Province, eastern China, were selected to study the relationship between soil physicochemical properties and soil enzyme activity with path analysis method. The influence degree and the mechanisms of soil properties on soil enzyme activity were also explored. Results showed that the variation characteristics of soil enzyme activity were affected by soil properties. The variation characteristics of soil cellulose enzyme activity were determined directly by soil available nitrogen and indirectly by soil readily available potassium to a certain extent. The content of organic matter played a very important role in the βglucosidase enzyme activity. Total porosity became main affecting factor of soil invertase activity because of its strong direct effect and indirect effects with other soil properties. The content of soil available nitrogen and field moisture capacity were dominant factors of polyphenol oxidase activity by determining most of its variation. Compared with correlation analysis and stepwise regression analysis, path analysis can objectively and comprehensively assess the influences of soil properties on soil enzyme activity.