ORGANIC-CARBON STORAGE IN SOILS OF SOUTHEAST CHINA

Studies on the quantities and distribution of soil organic carbon in d ifferent soil types and soils under different landuses can help to mee t our knowledge gaps in estimating the amount of carbon stored in glob al soils, and provide a scientific basis for assessing the magnitude o f management practices on carbon storage. This study was intended to e stimate the organic carbon density, distribution and mass in soils of southeast China based on the latest data available. Of the five landus es in southeast China, soils under natural forests have the highest or ganic carbon density of 11.84 kg m(-2), to a depth of about 100 cm, fo llowed by paddy soils (9.72 kg m(-2)), fruit land soils (7.99 kg m(-2) ) and upland soils (6.38 kg m(-2)) in order. Soils under natural spars e scrub and grass have the lowest organic carbon density, only about 3 .88 kg m(-2). The organic carbon density in different soil types, vari es from 3.14 to 30.98 kg m(-2), with the major zonal soils of latosols , latosolic red soils, red soils, yellow soils and yellow-brown soils having a density between 8.62 and 16.64 kg m(-2). Based on this study, the organic carbon stored in soils of southeast China is about 10.6 G t, constituting about 0.67-0.76% of the world total and about 2.1% of the organic carbon in tropical soils.