It is vital to estimate soil organic carbon density(SOCD)and its storage more accurately on natural secondary Pinus tabulaeforims forest land at Huoditang valley in Qinling mountains so that carbon balance of whole forest ecosystem could be better understood.

Based on a soil database from the soil sampling of Jiangxi by GPS in 2006, topsoil organic carbon density was calculated.

The soil organic carbon density and storage of Chongqing municipality was estimated based on the data of 1411 soil profile of Chongqing from the second soil survey of China, using the soil map (1∶250000), land use status quo map and district map of Chongqing.

Changes of soil active organic carbon pool under different land use types;

Reponses of soil labile organic carbon to different harvest methods and land use patterns after cutting were measured in Maoershan Experimental Forest Farm of northeast forestry university.

The results suggests that after partial cut with greater intensity in short-term,the amount of soil labile organic carbon will increase,but after forestation following clear cutting it will decrease in the temperate second growth of northeast China.

All of the above illuminated that short-term no-tillage could bring distinct changes of active soil organic carbon; Moreover (qCO2) and CPMI could indicate the changes of soil organic carbon pool more sensitively than other indices, which could be used as the important indicators for evaluating soil quality.

The research focused on active soil organic carbon(ASOC) in the processes of rocky desertification.