土壤碳库是陆地碳库生态系统的主体，在全球碳平衡中具有重要的作用。通过开展珠江三角洲经济区多目标区域地球化学调查，获得了土壤全碳及有机碳数据，采用“单位土壤碳量”方法计算土壤碳储量，显示珠江三角洲经济区土壤有机碳总体分布：表层（0~0.2 m）土壤有机碳为9.71×107 t，碳密度为2271.34 t/km2；中层（0~1.0 m）土壤有机碳为3.71×108 t，碳密度为8666.05 t/km2；深层（0~1.8m）土壤有机碳为5.87×108 t，碳密度为13722.73 t/km2。对比其他地区，珠江三角洲土壤碳密度处于较低水平。分析了土壤、土地利用、地貌类型与成土母质对区域土壤碳库的影响程度，不同土壤单元有机碳储量分布特征。与第二次土壤普查比较，20年期间珠江三角洲表层土壤有机碳总体减少0.22×108 t，损失幅度达19.20%，仅惠州等地区有所增加。不同生态系统土壤有机碳减少程度不同。%Soil carbon stocks are the main terrestrial ecosystem carbon pool, it has an important role in the global carbon balance. We have got the whole soil carbon and organic carbon data of the Pearl River Delta Economic Zone by conducting multi-target regional geochemical survey. Using the USCA (Unit Soil Carbon Amount) method, soil carbon storage in Pearl River Delta Economic Zone was calculated. Results show that topsoil (0~20 cm) organic carbon storage is 9.71×107 t with carbon density of 2271.34t/km2;subsoil (0~100 cm) organic car-bon storage is 3.71×108 t, with carbon density of 8 666.05t/km2;and deep soil ( 0~180 cm) organic carbon stor-age is 5.87 ×108 t,with carbon density of 13 722.73t/km2. Compared to other regions, the Pearl River Delta soil carbon density at is a low level. Analyzing of factors of soils, land use, landforms and soil parent material impact on soil carbon pool area, the different soil organic carbon storage unit distribution. Compared with the second na-tional soil survey, surface soil organic carbon in the Pearl River Delta during 20 years overall reduction of 0.22 × 108 t, a rate of 19.20 percent loss, only Huizhou and other regions increased. There have also been different de-creases in soil carbon density under various ecosystems and land use types.
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