Assessment of soil organic and carbonate carbon storage in China

Although the Kyoto Protocol does not require commitments from developing countries, carbon inventories are essential and required for further assessing the potential roles developing countries can play in mitigating the accumulation of CO2 in the atmosphere. Here we present estimates of terrestrial carbon pools as soil organic carbon and carbonate carbon in soils of China by using inventory data from the National Soil Resource Survey and Chinese Academy of Sciences. The total soil organic carbon and carbonate carbon in soils of China for a depth of 100 cm were estimated to be 83.8 Pg and 77.9 Pg C, respectively, and for whole soil profile was estimated to be 147.9 Pg and 234.2 Pg, respectively, with the sum of overall carbon storage 382.1 Pg. Terrestrial soil carbon storage and density (both organic carbon and carbonate carbon) in soils of China vary with and are modulated by bioclimatic conditions (temperature and precipitation/evaporation). The temperate regions have sequestered more terrestrial carbon in soils than the tropical and subtropical regions. This study suggests that terrestrial carbon in China is mainly sequestered in soil pool instead of aboveground forest biomass. Management practices of soils of China to stabilize and reduce carbon release from soil will play an important role in global carbon cycles.