Soil microbial community characteristics under different vegetation types at the national nature reserve of Xiaolongshan Mountains, Northwest China

Abstract

Microorganisms provide ecosystem services, such as decomposition and mineralization processes in forest soils. Quercus aliena var. acuteserrata and Larix kaempferi are the main natural forest and planted forest, respectively, in the national nature reserve of the Xiaolongshan Mountains of China. Understanding the composition and structure of soil microbial communities under these two typical vegetation types is critical for achieving effective management and sustainable utilization of the forest vegetation in the Xiaolongshan Mountain region. In this study, we analysed and compared the soil microbial communities of the Q. acuteserrata natural forest and L. kaempferi planted forest using high-throughput sequencing technology, and cultivated land soil samples were selected as controls. The results indicated that soil nutrient contents and stoichiometric ratios (organic carbon to total nitrogen ratio (C:N), organic carbon to total phosphorus ratio (C:P) and nitrogen to phosphorus ratio (N:P)) were higher in the natural forest than in the planted forest and were lowest in the cultivated land. The soil bacterial community in the Q. acuteserrata natural forest had lower diversity indices than that in the L. kaempferi planted forest and cultivated land, and the soil fungal community in the Q. acuteserrata natural forest had higher diversity indices than that in the cultivated land. Proteobacteria was more abundant in the natural forest soil with higher nutrient levels, and Acidobacteria was more abundant in the plantation forest soil with lower nutrient levels. Ascomycota abundance was lowest in the natural forest, and Basidiomycota abundance was lowest in the plantation forest. Microbial composition was sensitive to soil nutrients and the stoichiometric ratio, which explained 82.67% and 70.72% of the total variations in the soil bacterial and fungal community composition, respectively. There were significant differences in soil microbial community composition and structure between the natural forest and planted forest, and these changes were influenced by soil nutrient conditions. Total phosphorus (TP) may be an important factor regulating microbial community structure in different vegetation soil types.