Abstract: [Objective] In this study, we investigated the degradation of soil quality under different degrees of tourist disturbance, in order to understand the impacts of tourist activities on soil, to inform management on restoring soil quality, to provide basic data and theoretical basis for the scenic spot of eco-tourism planning and management.[Method] We investigated the properties of soil close to the main trail at a scenic spot in the park. Specifically, we selected three trails around 3 m in width. Along each trail, we established 3 plots away from the edge of the trail. The first plot was 1 m away from the edge, which represents high disturbance region. The second plot was 3 m away from edge, which represent middle disturbance region. The third plot was the control located at 7 m away from the edge. In each plot, we collected soil samples from different soil layers to determine density, water content, water holding capacity, pH value, total nitrogen, available phosphorus and enzyme indices of the soil. Factor analysis, principal component analysis (PCA) and the variation partition analysis were conducted to determine the contribution of each factor to the soil quality. Finally, the soil quality under different tourism disturbances was calculated by summing up the indices.[Result] The results showed that,with the increasing level of tourist disturbance, the water content, porosity and moisture content of the soil decreased whereas the bulk density and pH value increased, and the impacts of all these soil properties in the 0-5 cm layer was greater than those in the 5-15 or 15-25 cm layer. For soil nutrients, carbon-nitrogen ratio tended to increase while soil organic matter, total nitrogen and available phosphorus all decreased with increasing intensity of tourist disturbance; Soil urease, acid phosphatase, invertase, catalase activity of the tourist disturbed area were lower than those of the control plots, soil quality decreased at the same time; With the increase of depth of the soil layers, soil quality appeared to increase first and followed by a decrease. As the control plots were not interfered, their soil qualities of topsoil were the best, and the soil quality in deeper layers was getting worse.[Conclusion] Among them, soil organic matter, total nitrogen, invertase activity had larger contributions to the soil quality under the tourism disturbance, which could be used as indicators of soil health in this scenic spot. Therefore, we can monitor dynamically soil organic matter by investigating enzyme and organic matter content. On the other hand, we should also control the ecological environmental capacity by controlling the number of tourists in both temporal and spatial dimensions to ensure the sustainable development of scenic area and ecological benefits.

Key words: human trampling, physical and chemical soil properties, soil enzyme activity, factor analysis, integrated soil quality index