Distribution of¹⁴C and¹³C in forest soils of the dinghushan biosphere reserve

We report here first results on the bulk soil organic carbon (SOC), apparent radiocarbon ages and δ¹³C characteristics of the tropical and subtropical forest soil in Dinghushan Biosphere Reserve (DHSBR). The forest oxisol in Dinghushan has developed during the Holocene. The δ¹³C variation curves in all three profiles may be divided into two sections. The upper section from 0 to 40 cm has δ¹³C 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 δ¹³C. The mean δ¹³C values of the soil organic carbon could be used not only to discriminate between C₃ and C₄ plants, but also to distinguish between coniferous and broad-leaf plants.