The Changes of Soil Bacteria Community Characteristics Under Different Stages of the Expansion of Phyllostachys edulis

The Cunninghamia lanceolata forest(S), Phyllostachys edulis-C. lanceolata mixed forest formed by the expansion of P. edulis into C. lanceolata forest(H) and P. edulis forest formed by the long-term expansion of P. edulis(M) were targeted in Fengyang Mountain, Zhejiang Province. High-throughput sequencing was used to measure the composition of the bacterial community, and the relationship between soil bacterial community diversity and soil physical and chemical properties were analyzed. The results showed that the Operational Taxonomic Units(OTUs) and diversity index of soil bacterial communities were not different between the C. lanceolata forest and P. edulis-C. lanceolata mixed forest, but the OTUs and diversity index of soil bacterial communities in P. edulis forest were significantly higher than those in other forests. The numbers of unique OTUs were 759, accounting for 24.8% of the total OTUs of soil bacteria in P. edulis forest. The abundance of soil bacterial groups in bamboo forest changed greatly. The abundance of acidothermus, norank_f__norank_o__Elsterales, norank_f__Xanthobacteraceae and HSB_OF53-F07 genera decreased significantly, and a large number of new groups with abundance less than 1% appeared. The soil pH value and available phosphorus content of P. edulis forest increased significantly. The diversity index of soil bacterial communities was positively correlated with soil pH and available phosphorus, negatively correlated with soil bulk density, but weakly correlated with soil organic carbon. Following the protracted expansion of P. edulis into C. lanceolata forests, the soil acidification within the forested land was considerably mitigated. Consequently, the OTUs and diversity index of soil bacteria in the P. edulis, resulting from this expansion, were notably higher than those observed in the C. lanceolata forest and the P. edulis-C. lanceolata mixed forest. The expansion of P. edulis into C. lanceolata forest is beneficial to the improvement of soil bacterial diversity, which provides a reference for the evaluation of ecological function and ecological control under long-term expansion of P. edulis forest.