Soil Organic Carbon Dynamics And Validation Of InTEC Model In China's Subtropical And Temperate Zones

Soil is an important component and plays a leading role in global carbon cycling.Therefore, the study on terrestrial soil carbon cycling mechanism and responses to global change are an important foundation of predicting CO₂ content and global change. The study of soil carbon cycling is yet not fullest part in the research of carbon cycling in terrestrial ecosystem., It products greater error in predicting soil carbon pool. The complexity of soil in spaitial and temporal scale makes lots of problems that soil carbon cycling faced need to solved. The model of soil carbon cycling is important in carrying out simulating and predicting soil carbon cycling and is a effect tool synthesizing different factors and their interactions. The paper tries to introduce the Integrated Terrestrial Ecosystem C-budget model(InTEC model), analyzes the structure, modifies its parameters of soil carbon pools and simulates dynamics of soil organic carbon in China's subtropical and temperate zone.Soil sampled are obtanined from Liping county located in Guizhou province,Yujiang county in Jiangxi province, Changbai Mountains in Jilin province,Qilian Mountains in Gansu province and Ejina banner in Inner Mongolia. We sampled sixteen treatment according to different soil types and forest vegetation in Liping,nine treatment from forest and cropland soil,fifteen and twelve treatment according to its horizontal and vertical distribution and different soil and vegetantion in Changbai Mountains and Qilian Mountains respectively, nine from Ejina banner.two or three layers were sampled in every treatment in term of soil developed layer.The decomposition dynamics of soil organic carbon shows that there are different decomposition rate under different bands,vegetation and soil types.the gross trendency is there is a faster decomposition rate in the beginning incubation period than in the later period and in the surface soil than in the subsoil, the content of the first week evolved amounts comprised 15 to 49.52% of the gross evolved amounts,the decomposition date in Liping is higher than in Yujiang,in Changbai Mountains than in Qilian Mountains.The decomposition date under different soil and vegetation types decrease in the order of mixed forest,shrubs,broadleaf forest,chinese redpine,tea-oil tree in Liping county;The effect of age is mature Chinese fir>mid-aged Chinese fir>young Chinese fir,and of landuse is forest soil>cropland in Yujiang county;The effect of different soil types is swamp soil>plasma soil>tephra soil,and of different vegetations is mixed forest>Meiren pine forest>larch forest, and of different vegetations and soil types is silver fir forest of brown conifer soil>mixed forest of dark-brown soil>birch forest of tephra soil in Changbai Mountains; The decomposition date decrease in the order of mature spruce,original spruce,original Chinesefir under same soil types, in the order of sub-alpine meadow soil, forest dark-brown soil,mountain forest-grassland soil,alpine meadow soil,grey-calcreted soil under different soil and vegetation bands in Qilian Mountains;The effect of different vegetation is poplar forest landcoverd 45% areas> poplar forest landcoverd 15% areas>red willow>ole tree of thousand yesars in Ejina banner.Soil organic carbon pool is divided into three pools-active, slow and passive pool according to different turnover time. The three pools complies with first-order model Csoc=Ca exp(-kr t)+Cs exp(-ks t)+Cr exp(-kr t),We can simulate the soil active carbon pool and its decomposition rate,soil slow carbon pool and its decomposition making use of this first-order model. The content of active carbon pool from different vegetations accounts to percent 0.55-7.35% of total soil organic carbon and the mean residue time is 47days; slow pool, percent 47.86-70.55%, 21 years in Liping county; The content of active carbon pool from forest soil and cropland soil accounts to percent 0.99-2.89% ,0.56-2.43% of total soil organic carbon and the mean residue time is 15,7days respectively; slow pool, percent 17.14-55.46%,49.86-81.67%, 12,11 years r...