| Phyllostachys edulis is an important economic and ecological bamboo species with the widest distribution and the largest area in China.Moso bamboo forest is a typical stand of different age structure.As the rising labor costs,the high cost of traditional selective operation greatly compress the benefits of bamboo resource cultivation,limit on bamboo farmer's enthusiasm.Therefore,this study of the method of simulated mechanization harvesting to strip cutting of moso bamboo forest,the moso bamboo forest with different cutting strp width as the research object,based on Illumina Hi Seq 2500 sequencing platform,using 16 s r RNA V3-V4 sections,ITS1 primer to high-throughput sequencing of soil bacteria and fungi.The community composition,function and diversity characteristics of soil bacteria and fungi in bamboo forest were obtained.By analyzing the response characteristics,functional prediction characteristics and phylogenetic characteristics of soil nutrients and enzyme activity after strip logging,the influence mechanism of strip logging on the soil microbial community structure of bamboo forest was explored.The results show that:(1)A total of 17 phylum,40 class,85 order,126 family,195 genus,213 species were obtained for bacteria,and 10 phylum,27 class,58 order,96 family,138 genus,117 species were obtained for fungi.Among the dominant bacterial flora,only the Actinobacteria increased significantly in the 3m cutting zone.There was no significant effect of strip cutting on the dominant fungal flora.(2)The Ace index of soil bacteria in 3m and 9m cutting zones significantly increased after strip cutting,and Chao1 index in 3m cutting zones significantly increased.Shannon and Simpson diversity index changed irregularly,and there was no significant difference between different cutting zones,indicating that strip logging had a significant impact on the abundance and quantity of bacteria,but had no significant impact on the species diversity of bacteria.There was no significant change in the Alpha diversity index of soil fungi and the Beta diversity of soil bacteria and fungi.The function diversity of KEGG,COG and Bug Base of soil bacteria and FUNGuild function grouping of fungi were not significantly changed.(3)In the bacterial groups with high abundance,Actinobacteria were positively correlated with total phosphorus(p<0.01),Firmicutes were positively correlated with total phosphorus and available nitrogen(p<0.05),Actinobacteria were negatively correlated with catalase and N/P,and Planctomycetes were negatively correlated with available nitrogen(p<0.05).Total phosphorus,rapidly available nitrogen,catalase and N/P are the main driving factors for the change of bacterial community structure in soil.(4)In the abundance of higher fungi taxa,Basidiomycota and available nitrogen content is significantly negative correlation(p<0.01).Rozellomycota and C/N very significant positive correlation(p<0.01),Rozellomycota and p H,organic matter,catalase,phosphatase,urease,C/p was significantly positive correlation(p<0.05).Rozellomycota and total potassium significantly negative correlation(p<0.05).Ascomycota and total nitrogen content,N/P was significantly positive correlation(p<0.05).Mortierellomycota and soil organic matter and C/P,N/P was significantly negative correlation(p<0.05).Soil p H,rapidly available nitrogen,phosphatase and urease are the main driving factors of fungal community change.(5)The Ace index of bacteria was significantly positively correlated with total phosphorus(p<0.05),and Chao1 index was significantly positively correlated with total phosphorus(p<0.01).The Ace and Chao1 index of fungi were negatively correlated with N/P(P <0.01),while the Chao1 index was positively correlated with total phosphorus and available potassium(P<0.05).There were 725 correlation relationships among bacteria genera and 361 among fungi.The network correlation of bacteria was more complex than that of fungi,and the bacterial community was more stable than that of fungi in response to the interference of strip cutting.(6)Net Relatedness Index(NRI),Nearest Taxon Index(NTI)of bacteria and fungi are greater than zero,that soil bacteria and fungi community belong to phylogenetic clustering in the reservation and the cutting zone,maintaining mechanism of microbial community structure in conformity with the niche theory,the environmental factor to determine the microbial community structure.Strip logging has no significant effect on NRI and NTI of soil bacteria and fungi in bamboo forests,and the phylogeny of bacteria and fungi still tend to cluster.After strip logging,the NTI of soil bacteria and fungi decreased,and the phylogenetic distance between the related species of soil microorganisms became longer,and the ecological niche was also differentiated.The above results reflect the response characteristics and mechanism of the soil microorganisms in moso bamboo forest to the interference of strip logging.In the early recovery stage of moso bamboo forest after strip logging,it has no significant influence on the species composition,function,diversity and phylogenetic characteristics of the subsurface soil microbial community,except that the bacterial abundance significantly increases at 3m and 9m cutting zone.The structure of the soil bacteria community was most similar in the 9m cutting zone,and the structure of the fungus community was most similar in the 12 m cutting zone,indicating that the stability of the soil microbial community in the 9m and 12 m cutting zone was relatively good after strip cutting.In the process of short-term recovery after strip cutting,the cutting zone width has not reached the moderate disturbance degree of soil microbial community.According to the existing research results of productivity index and soil property change characteristics of bamboo forest after strip cutting,it is better to set the cutting width of 6?9m.If strip cutting is used to manage bamboo forest in a short period of time,9m cutting width can be set.The resilience and resistance of soil microbial community are strong,and the stability is high. |
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