利用CENTURY模型研究东北黑土有机碳的动态变化Ⅰ．自然状态下土壤有机碳的积累

应用CENTURY模型，对自然状态下的黑土有机碳库进行了模拟．结果表明，在自然状态下，黑土有机碳库经历了一个由快到慢的增长过程，经过长时间积累，趋向于稳定状态．0～20cm表层土壤有机碳总量最后稳定在7914．72～11672．78g·m^-2．黑土有机碳从北向南总的趋势是逐渐降低．达到稳定状态时，活性土壤有机碳库、慢分解土壤有机碳库和惰性土壤有机碳库分别占土壤全碳的3．36％～4．62％、50．54％～55．47％和36．47％～41．95％，可见慢分解和惰性组分库的增长对土壤有机碳库的积累起到了重要作用．模型模拟结果与已发表的实测结果比较接近，可以为进一步研究开垦后黑土有机碳变化提供依据．

Dynamics of organic C in black soil of Northeast China,simulated by CENTURY model I.Accumulation of soil organic carbon under natural conditions

By using CENTURY model, this paper simulated the dynamics of organic carbon and its fractions, including active, slow and passive pools, in black soils under natural condition at Nenjiang, Beian, Hailun and Harbin in Heilongjiang Province and at Gongzhuling in Jilin Province. The results showed that soil organic carbon had increased for a long time, and tended to reach the steady state. In the steady state, soil organic carbon reached 7914.72-11672.78 g x m(-2), which decreased from north to south in geperal. The active, slow and passive fractions were 3.36%-4.62%, 50.54%-55.47% and 36.47%-41.95% of soil organic carbon pool, respectively, which indicated that slow and passive fraction were the main body of soil organic carbon in native ecosystem. The simulated results were in agreement with some observed results, which can be used as the original data in the study on the dynamics of soil organic matter after cultivation.