Abstract:In order to reveal the characteristics of soil active organic carbon and carbon pool allocation under different vegetations in Jinyun Mountain in Chongqing, broad-leaved forest, coniferous forest, mixed forest, bamboo forest and wild grassland were taken as research objects. The contents of soil organic carbon (SOC), microbial biomass carbon (MBC), dissolved organic carbon (DOC) and easily oxidized organic carbon (ROC) in each soil layer within 0-100 cm were measured, and the changing characteristics of soil organic carbon storages (SOCS) were also studied and compared. The results showed that the content and distribution ratio of SOC and active organic carbon components were significantly affected by vegetation type and soil depth. The average content of SOC in 0-100 cm soil layer was in order of bamboo forest (16.74 g/kg) > broad leaved forest (12.62 g/kg) > grassland (11.14 g/kg) > mixed forest (8.16 g/kg) > coniferous forest (5.98 g/kg), and decreased with increasing soil depth under all vegetation types. The contents of MBC and ROC in bamboo and broad-leaved forests were significantly higher than those in mixed and coniferous forests, and both declined with the increasing soil depth under all vegetation types, showing the significant surface aggregation effect. Except for grassland, soil carbon pool management indexes under other 4 vegetation types decreased with increasing soil depth, and were the highest in the surface layers (0-20 cm soil layer). Among different vegetation types, the proportion of DOC in bamboo forest was the smallest in each soil layer, with an average value of 0.1% for the whole soil profile. The correlation analysis showed there were extremely significant correlation between MBC, ROC, SOC and SOCS. Therefore, MBC and ROC can be used as an important indicator to evaluate the dynamic changes of soil carbon pool in the study area.