Abstract: Double component model was used to simulate the soil organic carbon dynamics after changing landuse pattern in hilly red soil region of subtropical China, and investigation and monitoring data were used to evaluate it.The model distinguished soil organic carbon into two compartments, i.e.newly formed organic carbon and native organic carbon.The transformation of each kind of organic carbon was described by the first-order kinetics function, and the changing process of soil organic carbon storage in four landuse patterns of masson pine forest, slash pine forest, citrus orchard and pasture since natural subtropical soils being reclaimed for 10 years was simulated.The results show that this method fits to simulate the dynamic process of soil organic carbon storage during the early stage of changing landuse patterns with different soil types.

Key words: Hilly red soil region, Change of landuse pattern, Soil organic carbon, Simulation, dynamic ecological security pattern, ecological network, betweenness centrality index, correlation length-percentage of importance of omitted patches, Qingdao City