利用生物地球化学模型进行土壤有机碳演变模拟现已成为研究热点。以往的模拟中国农田土壤有机碳演变的研究所采用的土壤数据比例尺较小，忽视了土壤属性的空间异质性，所估算的结果存在着较大的不确定性。此外，在模型验证方面，也仅仅根据田间长期定位观测结果对模型进行验证，缺少区域尺度上的验证。本项目以中国旱地农田土壤为研究对象，整合Century模型和中国1：100万土壤数据库以及气象、作物、耕作管理等GIS数据，以充分体现土壤属性空间异质性的“旱地农田-土壤图斑”为模拟单元，主要研究：1）模拟了1985~2015年中国旱地农田土壤有机碳演变规律和空间分布；2）运用2000年1000多个实测点数据对模拟结果进行区域验证；3）同时深入探讨了土壤有机碳演变的土类差异和区域差。研究结果对于实现我国农业可持续发展和制定固碳减排政策制定具有重要意义。

At present, biogeochemical models are often used to simulate dynamics of soil organic carbon (SOC). However, previous model applications at national scale were primarily limited to small mapping scale, which largely ignored the spatial heterogeneity of soil properties, resulting in greater uncertainty for SOC estimates. In terms of modeling verification, the modelling results were only validated with field scale studies, and long-term static observational data, due to lack of availably spatio-temporal soil data at the regional scale. Therefore,.this study focuses on modeling SOC dynamics for dry farmland soils of China. The Century model was integrated with a 1 : 1 000 000 soil database of China and GIS databases of weather, crop and agricultural management practice. Then based onthe dry farmland-soil polygons extracted by using spatial overlay analysis of the 1 :1000 000 soil database and the 1 : 1 000 000 landuse database of China, SOC dynamics and its spatial distribution from 1985 to 2015 for dry farmland of China were simulated by the Century model which was one of the most extensively used and well validated SOC models worldwide and the modeled results were validated at regional scale using more than 1 000 measured data in the year 2000. Meanwhile, variation among soil group and regional variation of SOC dynamics were discussed..The results is of great significance in realizing the sustainable development of agriculture and making the strategy of carbon sequestration in cropland soils of China.