Effects of litter and root inputs on soil microbial community structure in subtropical natural and plantation forests

Aims

Soil microorganisms play a pivotal role in forest ecosystems geochemical cycle, yet their responses to variations in aboveground and belowground carbon inputs remain insufficiently understood. Variations in plant-derived carbon inputs are expected to influence microbial community structures. This study aims to investigate how changes in these carbon inputs affect the composition and diversity of soil microbial communities across different forest ecosystems in the subtropics forest.

Methods

Natural forest and plantation of Castanopsis carlesii in the subtropics were selected, with three 20 m × 20 m plots established in each forest. Six treatments were applied in a randomized complete block design, with aboveground litter excluded using nylon nets and root exclusion achieved by trenching. Soil microbial community structure under each treatment was analyzed using high-throughput amplicon sequencing.

Results

Litter and root treatments significantly altered microbial community composition and diversity. Bacterial communities, dominated by Acidobacteria, Proteobacteria, and Actinobacteria, showed no significant structural changes in response to treatments but were influenced by forest type. In contrast, fungal communities, dominated by Basidiomycota and Ascomycota, exhibited reduced diversity under root exclusion and litter treatments in natural forests. Soil properties such as moisture, temperature, DOC, and DON were key drivers of microbial community structure and diversity.

Conclusion

These results underscore the role of ecological niche differences between forest forests and alterations in soil chemical properties induced by litter and root inputs in shaping soil microbial communities. These findings offer insights into the mechanisms governing nutrient cycling and soil carbon dynamics in subtropical forest ecosystems.