Distribution of 14 C and 13 C in Forest Soils of the Dinghushan Biosphere Reserve

We report here first results on the bulk soil organic carbon (SOC), apparent radiocarbon ages and δ 13 C characteristics of the tropical and subtropical forest soil in Dinghushan Biosphere Reserve (DHSBR). The forest oxisol in Dinghushan has developed during the Holocene. The δ 13 C variation curves in all three profiles may be divided into two sections. The upper section from 0 to 40 cm has δ 13 C values varying from −27.4 to −24.1‰, −27.5 to −22.2‰, and −24.4 to −20.1‰. in the Wukesong, Qingyunsi and Kengkou profiles, respectively. The lower section, including the 40–160 cm horizons, has a uniform δ 13 C. The mean δ 13 C values of the soil organic carbon could be used not only to discriminate between C 3 and C 4 plants, but also to distinguish between coniferous and broad-leaf plants.