Introduction
Soil carbon (C) sequestration by terrestrial vegetation, as one of the main approaches for greenhouse gas (GHG)
mitigation, has long been identified by the Inter-govern mental Panel on Climate Change . Terrestrial ecosystems associated with land use and soil management play an important role in the global C budget . For example, the current global terrestrial sink for C is estimated to hold 550-700 Pg of C in vegetation and 1200-1600 Pg in soil organic matter. Soil is the largest terrestrial C pool, constitutes at 2500 Pg of total C (organic and inorganic) within one meter depth . This soil C pool is approximately two-thirds of the total C in ecosystems . The former is about 3.3-fold greater than the atmospheric C pool (760 Pg), and 4.5-fold greater than the biotic C pool (560 Pg) . In addition, soil organic carbon (SOC) pools have the slowest turnover rates in general terrestrial ecosystems , therefore C sequestrated in soils has
a great potential to mitigate CO2 emission to the atmosphere .