Distribution and Storage of Soil Organic Carbon in Hainan Island

Organic carbon data from 8713 surface soil samples and 2197 deep soil samples were used to calculate organic carbon density at the depths of 0～20 cm,0～100 cm,and 0～180 cm of the soil in Hainan Island.The results are 2.86 kg·m-2,9.48 kg·m-2,and 13.72 kg·m-2,respectively,almost the lowest level,as compared to those in other typical domestic areas in China.Regional soil organic carbon density map shows that the distribution of soil organic carbon has close relationship to the landscape type,the high-value areas are in the mountains,hills,volcanic platforms,followed by plains,while coastal areas the lowest.Statistics shows that soil organic carbon density of different land use types and soil types also have significant difference.The soil organic carbon density level of types of land use range in following order:garden landwoodlandother landarable land,and soil organic carbon is mainly stored in woodland,arable land.Soil organic carbon density level of types of soil are in following order:yellow soilred soillateritepaddy soildry red soil,and soil organic carbon is mainly stored in laterite,red soil,paddy soil.According to the statistics,in Hainan Island,soil at the depth of 0～180 cm reserves 478.13Mt organic carbon.