Storage and distribution of soil organic carbon in different age-group Chinese fir plantations

A comparative investigation was made to study storage and distribution of soil organic carbon in Chinese fir plantation ecosystems of three age-group in 0 ~ 60 cm soil layer in Fushou Forest Farm. The results show that:(1) the profile SOC declined along with the soil depths increased in three age-group fir plantation, the storage of SOC in 0 ~ 20 cm soil layer was highest from 29.07 g·kg-1 to 35.27 g·kg-1, being from 1 to 2 times as much as those in 20 ~ 30 cm and from 3 to 4 times as much as those in 30 ~ 45 cm, respectively. However, the storage of SOC in 45 ~ 60 cm soil layer was lowest from 5.03 g·kg-1 to 6.68 g·kg-1.(2) the average storage of SOC in 0 ~ 60 cm soil layer and carbon density decreased first and increased afterwards, the average storage of SOC varied in the order of mature(16.65 g·kg-1) young(14.78 g·kg-1) middle-aged(13.36 g·kg-1) and the carbon density varied in the order of mature(79.59 t·hm-2) young(64.78 t·hm-2) middle-aged(64.74 t·hm-2).(3) the storage of SOC were from 86% to 91% of the total storage of SOC in 0 ~ 45 cm, the soil organic carbon mainly concentrated from 0 to 45 cm soil layer.