Effects of invasion of elsholtzia densa Benth. on soil properties and soil bacterial diversity in alpine meadow of Qinghai-Tibet plateau.
Objective: The present paper aimed to explore the expansion mechanism of ELshatia densa Benth., a common weed species of degraded alpine meadow and farmland ecosystem in Qinghai-Tibet Plateau.; Method: The community characteristics of E. densa invading patches and control patches were investigated, and the Miseq high-throughput sequencing technology combined with soil nutrient and extra-cellular enzyme activity determination was adopted.; Result: The changes of community coverage and plant diversity index of E. densa inva-ded patches were not significant, but the total biomass decreased and leguminous plants were excluded. A total of 33 bacteria were detected from the tested soil, including 30 from rhizosphere soil and 27 from non-rhimphere soil. Shannon-winner index, Simpson index and Chaol index are respectively 9.22, 0.99 and 3024.91 in rhizosphere soil and 9.09, 0.99 and 2707.58 in non-rhizosphere soil. Actinobacteria, Proteobactetia Bacteroidetes, Firmicutes, Acidobactetia and Ganmatimonadetes are the dominant phylum of soil bacteria. Among them, the rhizosphere soil has the highest proportion of Proteobacteria, while the non-rhizosphere soil has the highest proportion of Actinobacteria. Compared with non-rhizosphere soil, the contents of organic matter, total phosphorus, total potassium, total nitrogen, available phosphorus and available nitrogen increased significantly (P-40.05), but the available potassium decreased significantly (PE0.05). Among them, a-vailable phosphorus increased the most, which was 6.88 times that of non-rhizosphere soil, followed by organic matter and total nitrogen con-tent. The activities of urease, sucrase cellulose and polyphenol oxidase increased significantly (Pt.c0.05), while the changes of acid phosphatase were not significant.; Conclusion: I Changing soil characteristics and bacterial diversity is one of the mechanisms of E. densa expansion.