运用农业生态系统生物地球化学模型 (DNDC) ,估算北方农牧交错带内蒙古自治区耕地土壤C储量并研究其平衡状况结果表明 ,该区耕地 0～ 3 0cm土层土壤有机碳储量约为 4662 2 .6万t ,目前土壤有机碳库处于严重负平衡 ,年净损失有机碳 13 3 5万t。指出干旱半干旱农牧交错区应推行免耕、休耕等保护性耕作措施以助于土壤有机碳的积累 Using the model of biogeochemical biogeochemistry (DNDC) in the agroecosystem to estimate the C reserves of the soil in the ecotone between agriculture and animal husbandry in Northern China and the study on its balance, the results show that the soil organic carbon storage in the 0 ~ 300 cm soil layer is 4662 2. At present, the soil organic carbon pool is in a serious negative balance with an annual net loss of 13.35 million t of organic carbon. It is pointed out that conservation tillage such as no-tillage and fallow should be promoted to promote the accumulation of soil organic carbon in the arid and semi-arid agro-pastoral ecotone