Soil organic carbon storage and its spatial distribution in Gansu Province

Based on 37 soil type,281 soil profiles and the area of all kinds soil type from the Second Gansu Soil Survey,and 1:300 000 soil chart in Gansu Province,we estimated its soil organic carbon storage by using GIS to analyzes its spatial distribution.The results showed that in this province,soil organic carbon storage was about 39.87×108t accounting for 4.47% of the total in China.The top five soil types in organic carbon storage were cryo-sod soil,frost-sod soil,peat soil,cinnamon soil and cryo-calc soils.Totally taking up 39.67% of that in Gansu.The organic carbon density was the highest in peat soil(208.53kg·m-2).In this province,soil organic carbon density was about 17.62kg·m-2 on average,being higher than that(9.60kg·m-2) in this country.The organic carbon density was the lowest in Skeleton soils(0.73kg·m-2).In general,the density of soil organic carbon in Gansu Province mostly varied from 0～15kg·m-2.