Abstract: Focused on soil organic carbon （SOC） content in rubber plantations with different stand age， the soil organic carbon distribution at temporal and spatial scales had been analyzed in Mengla， Xishuangbanna. It was shown that SOC content of 10， 20， 30 a rubber plantation was 951-1088， 736-788， 878-931 g.kg-1， respectively， and organic carbon storage decreased as 10 a>30 a>20 a. SOC content gradually decreased with the increasing depth of soil layers， and there was no significant difference in SOC content in 0-45 cm soil layer of 20 a， 30 a rubber plantation. SOC content in the same soil layer differed significantly among rubber plantations with different stand age. But， the majority of SOC concentrated in 0-30 cm soil layer， especially in 0-15 cm soil layer. SOC storage in the surveyed rubber plantations were 4750-6641 t·hm-2， and exhibited similar trend in different soil layers and different stand age plantations as SOC content. Compared with rubber plantations in Danzhou， Hainan Province， the SOC storage in rubber plantations in Xishuangbanna was larger， while， the variation of SOC in depth was less in Xishuangbanna.

Key words:  rubber plantations, stand age, soil organic carbon