Abstract: The path analysis was used to analyze the soil physicochemical factors and 5 kinds of soil enzyme activities under the Pinus sylvestris var. mongolica plantation with 10-60 year stand ages in the Zhanggutai area of Liaoning Province. The results showed that the 5 kinds of soil enzyme activities in the study area were significantly correlated with most soil physicochemical factors, so the soil enzyme activities could be used to characterize the comprehensive soil fertility in this region. The main factors affecting the different soil enzyme activities were different, and the main factors affecting the sucrose enzyme were the contents of organic matter, clay and available phosphorus as well as pH value. The main factors affecting the protease were the contents of alkali-hydrolyzed nitrogen, available potassium and soil moisture. The main factors affecting the phosphatase were the contents of total phosphorus, available potassium and powder. The main factors affecting the catalase were the pH value, bulk density and contents of total phosphorus and total potassium. The main factors affecting the urease were the pH value and the contents of clay, total nitrogen and soil moisture. Compared with the simple correlation analysis, the path analysis could be used to better understand the relationship between soil enzyme activity and soil physicochemical factors. It is expected to provide a basis for soil improvement under Pinus sylvestris var. mongolica plantation through studying the main factors affecting soil enzyme activity.

Key words: Pinus sylvestris var. mongolica, plantation, soil enzyme, enzyme activity, affecting factor, path analysis, Liaoning Province