Diversity of soil microbial in Pinus massoniana secondary forest under different logging intensities and vegetation restoration years

This study adopted a space-for-time substitution method and the secondary Pinus massoniana forest suffering from Bursaphelenchus xylophilus. in the subtropical region was selected as the research object. Two cutting methods(moderate logging ML and heavy logging HL) and three natural recovery periods(0 a, 5 a, 15 a) were set up The high-throughput sequencing technology was used to analyze the diversity of soil microbial communities and their relationship with soil nutrients. The results showed that the available nutrients in 0-10cm soil layer, such as organic matter and alkali hydrolyzed nitrogen, significantly increased with the restoration years. Additionally, both the logging intensity and restoration years jointly influenced the organic matter content in the 10-20cm soil layer. The richness and diversity of soil bacteria and fungi were significantly affected by the interaction between the logging intensity and the restoration years, and they increased with the extension of the restoration period. There are 1581 species of bacteria belonging to 35 phyla, 87 classes, 178 orders, 217 families, and 357 genera in the secondary forest soil of Pinus massoniana, while there are 1578 species of fungi belonging to 5 phyla, 36 classes, 111 orders, 277 families, and 750 genera.The main dominant bacterial phyla included Acidobacteria and Proteobacteria, while the dominant fungal phyla were Ascomycota and Basidiomycota. Rapidly available potassium was a key factor affecting the characteristics of the microbial community, while organic matter, available phosphorus, and rapidly available potassium were positively correlated with bacterial diversity indices. Alkali hydrolyzed nitrogen was the main factor affecting the variation of deep soil fungi. In conclusion, moderate logging and natural restoration contribute to increasing soil nutrient content and microbial diversity, promoting positive succession and soil fertility maintenance in forest ecosystems.