Seasonal Dynamics of Soil Organic Carbon and Microbial Communities Under Distinct Viburnum Species

Study on soil organic carbon and microbial communities in different Viburnum stands to provide data support for optimizing urban landscape plant configuration. This experiment took four Viburnum species (Viburnum dilatatum, Viburnum keteleeri, Viburnum corymbiflorum, Viburnum rhytidophyllum) as research subjects, with surrounding grassland as control, and investigated seasonal changes (spring, summer, autumn) in soil organic carbon and microbial communities. Results showed: Soil organic carbon content in different Viburnum stands was higher than grassland, indicating planting Viburnum in urban landscapes aids soil carbon sequestration. Total PLFA in different Viburnum stands differed significantly, with Viburnum keteleeri having the highest total PLFA, notably exceeding other treatments during spring and autumn. Planting Viburnum keteleeri significantly increased subsurface soil G⁺, G⁻ bacteria, fungi, and actinomycetes contents. Compared with grassland, microbial community increases under Viburnum keteleeri followed: fungi (68.11%) ＞ actinomycetes (61.67%) ＞ G⁻ bacteria (52.77%) ＞ G⁺ bacteria (40.07%) ＞ mycorrhizal biomass (25.00%). Planting Viburnum keteleeri more effectively improved soil microbial community structure—particularly fungi and actinomycetes—compared to Viburnum dilatatum, Viburnum rhytidophyllum, and Viburnum corymbiflorum. Conclusion: Different Viburnum stands significantly differ in influencing soil organic carbon and microbial communities; planting Viburnum keteleeri better enhances soil organic carbon content while elevating total soil microbial biomass and richness.