Data from: Microbial necromass carbon drives soil organic carbon accumulation during long-term vegetation succession

This dataset presents data on plant- and microbial-derived carbon (C) from long-term vegetation succession sequences on the Loess Plateau. It includes three files: “Plant lignin phenols.xlsx”, “Microbial necromass carbon.xlsx”, and “Soil chemical and biological properties.xlsx”. These data were obtained from field surveys and laboratory analyses to assess the contribution of plant- and microbial- derived C to soil organic carbon (SOC) during vegetation succession. The results showed that a unimodal distribution of total lignin phenols along succession, peaking at 100 years. Vegetation succession significantly increased microbial-derived C, including microbial necromass C (MNC) and glomalin-related soil proteins (GRSP). The contribution of MNC to SOC was high and increased significantly with vegetation succession, whereas the proportion of plant-derived C and GRSP in SOC consistently decreased. In addition, the distribution of lignin phenols is determined by the quality and abundance of plant litter input to the soil, and the increase in microbial-derived C is closely associated with microbial metabolism mediated by environmental factors. However, the C turnover pathway from microbial necromass to persistent SOC formation, as inferred from the nonlinear response of the MNC accumulation coefficient, requires 90–100 years to achieve a stable contribution to soil C sequestration. These findings further highlight the critical role of the microbial C pump in SOC formation and accumulation, providing new insights on sustainable soil C sequestration practices during ecological restoration.