N-fixing tree species regulates the effects of tree richness on fine root decomposition

A 9-year tree species richness experiment with four species gradients (1, 2, 4, and 6 species) interacted with/without N-fixing tree species was conducted in subtropical forests. Fine root traits and decomposition rate, soil microbial biomass, soil extracellular enzymatic activity, and changes in SOC based on an in situ microcosm incubation were measured to determine the effects of tree species richness and N-fixing tree species on fine root decomposition and SOC storage.