Abstract: [Objective] This study aimed to reveal the response characteristics of soil microbial community structure to different disturbance types in Masson pine (Pinus massoniana) plantation, and to explore the microbial mechanism of soil quality change, and to evaluate the effects of different tree removal disturbance types on underground ecosystems. [Method] Four different treatments of shrub removal (SR), light disturbance (LD) (removal of non-Masson pine tree with DBH>4 cm, i.e. 15% of basal area removed), heavy disturbance (HD) (removal of Masson pine tree with DBH>17.9 cm, i.e. 70% of basal area removed), and control (CK) were conducted in a P. massoniana plantation. The topsoil of 0-10 cm was collected in all plots on July 13, 2015, and Illumina Miseq high-throughput sequencing method was used to analyze the response characteristics of soil microbial community composition and structure under different disturbances. And the response mechanism of microbial was preliminarily explored by combining similarity and phylogenetic index. [Result] 1) Proteobacteria, Acidobacteria and Actinobacteria were the dominant bacteria in the soil of P. massoniana plantation, and Basidiomycota, Ascomycota and Zygomycota were the dominant fungi. Significant differences in the relative abundance of bacterial communities were tested at the phylum level, and the result showed that the relative abundance of Bacterioids, Beaproteobacteria, DeltaProteobacteria and Gammaproteobacteria were significantly different (P < 0.05). The soil microbes with different interference types were compared with the control plot. Compared with Control (CK), the relative abundance of Proteobacteria, Betaproteobacteria, Deltaproteobacteria and Gammaproteobacteria in LD was significantly decreased, and the relative abundance of Bacterioids and Deltaproteobacteria in HD was significantly lower (P < 0.05), but there was no significant change at the level of phylum and class in SR plots. 2) The results of principal component analysis showed that the soil microbial (bacterial and fungal) community structure could be distinctly separated in different disturbed plots, and the non-parametric multivariate analysis of variance (PMANOVA) showed that there were significant differences between the bacterial and fungal community structure in different disturbed plots (P < 0.05). The community structure of soil microorganisms in different disturbed plots except SR plots was significantly different from that in control plots (P < 0.05), and there was significant difference in the fungi community structure between the disturbed plots and the control (P < 0.05). 3) Compared with CK, the similarity of bacteria decreased significantly in LD and HD (P < 0.05). Also, the similarity of fungi was significantly different in SR, LD and HD (P < 0.05). 4) The analysis based on the zero model showed that only the changes of Phylogenetic abundance and Phylogenetic diversity of soil microbial communities with LD reached a significant level (P < 0.05). [Conclusion] The disturbance of P. massoniana plantation significantly affected the composition and structure of soil microbial community, and the disturbance reduced soil nutrient availability; the disturbance significantly reduced the similarity of soil microbial community, resulting in the decline of soil microbial community stability; In addition, the disturbance changed the Phylogenetic diversity of soil microorganism, that is, the nutrient content and niche diversity of soil microorganism was changed, which reduced the stability of the ecosystem. Both LD and HD significantly reduced soil quality, resulting in a decrease of soil nutrient content, therefore, LD and HD in Masson pine plantations should not be used.

Key words: Masson pine plantation, forest management, Illumina Miseq sequencing, forest soil