Abstract:Soil organic C plays a key role in carbon cycle and carbon storage in the natural ecosystem.The soil carbon stocks under native vegetations in China were estimated by making use of 2 440 profiles from the second national soil survey and the vegetation map (14 000 000) of China,and map the distribution of soil carbon density under native vegetations.With the aid of a simplified vegetation classification system,the digitalized vegetation map units were sorted into 6 categories and 26 types of vegetation.The median carbon stocks of the soils in China are 8.23 kg m-2 in 0~100 cm soil layer,and 2.67 kg m-2 in 0~20 cm topsoil.The difference in the soil carbon density among vegetation categories is prominent.The soil carbon density in 0~100 cm under forests,scrubs,deserts,steppes,meadows and croplands is 11.59,7.25,3.14,5.29,14.90 and 8.07 kg m-2,re spectively.On the basis of vegetation types,the total soil carbon stocks were calculated at 69.38 Gt in 0~100 cm and 23.81 Gt in 0~20 cm.In 0~100 cm,the soil carbon stock under forests (17.39 Gt) was the highest,accounting for 25% of the total in China despite the fact that the forest soil amounted to only 15.81% of the total territory of the country.Under croplands,it was 14.69 Gt or 21.2%,a little higher than the percentage (19.18%) of the soil in area.Though the soil under the vegetation of meadows and swamps was low (8.64%) in percentage in area,its carbon storage amounted to 12.22 Gt or 17.63%.The soil carbon stocks under steppes were 14.69 Gt or 10.76% of the total,lower than the percentage (14.86%) of the soil in area,and it was 3.93 Gt or only 5.66% under deserts,much lower than the percentage (13.17%) of the soil in area.