Mixed-species afforestation promotes soil organic carbon by shaping fine root vertical distribution and morphology

A field experiment was conducted in three even-aged and similarly managed plantations (Castanopsis hystrix monoculture, Pinus massoniana monoculture, and C. hystrix-P. massoniana mixed plantation) in subtropical China. We measured species-specific fine root biomass, root morphological traits, particulate organic C (POC), and mineral-associated organic C (MOC) across different soil depths to assess how fine root vertical distributions and changes influence SOC in different plantations.