Abstract:

【Objective】 In present study, the structure of soil microbial community, activities of soil-enzyme and changes of fertility in different Ageratina adenophora invaded areas were analyzed for understanding the impacts of alien invasive plant on soil ecosystem. 【Method】 Soil samples were taken from different communities: heavily-invaded area, medium-invaded area, newly-invaded area, non-vegetation area, single-native-plant area, and multi-native-plants area, which are within similar ecological situations, soil biota were analyzed by traditional cultural methods, soil enzyme activities and fertilities were measured using the traditional chemical-factor analyzing methods. 【Result】 Compared to non-vegetation and native-plant soils, it was most noticeable that A. adenophora increased soil organic carbon, NO3--N, NH4+-N, available P, available K content and the activities of urase, phosphatase and invertase. NH4+-N content in the heavily-invaded soil was 53.00 mg?kg-1, which was 14.1, 9.9, and 5.9 times as that in the non-vegetation, multi-native-plants and single-native–plant soils, respectively. The activities of urase in the heavily-invaded soil was 2.87, which was 2.9 and 3.9 times more than that in the multi-native-plants and non-vegetation soils, respectively. The quantity of soil fungi, azotobacteria and ammonia oxidizing bacteria were most abundant in the heavily-invaded area. 【Conclusion】The results indicate that A. adenophora changed soil microbial communities, especially the soil nutrition cycling and soil enzyme related soil microbe groups, probably creating a favorable soil environment which is of benefit to itself. The invasion-induced changes of soil microbial community and physical and chemical properties may be used by A. adenophora to expand rapidly in invasive ranges.

Key words: biological invasion, Ageratina adenophora, activity of soil enzyme, soil fertility, soil microbial community