中文摘要：

以现有的农田土壤有机碳动态模拟模型（Soil-C）为基础，针对湿地垦殖的特点及土壤有机碳的物理属性，将原模型中土壤有机碳单一分室改进为轻组和重组两分室进行模拟，并利用较大时空差异的土壤有机碳测定数据对模型进行了验证。结果表明，改进后的模型能较好地模拟湿地垦殖对土壤有机碳的影响，模拟值与观测值具有良好的一致性，原模型对垦殖湿地土壤有机碳变化的模拟能力较弱。

英文摘要：

The conversion of wetland to cropland is believed to induce soil organic carbon （SOC）loss. To simulate the changes in SOC due to marshland conversion, an existing model （Soil-C）was modified in this paper. Soil-C was originally developed to simulate SOC dynamics in cropland, in which SOC was simply viewed as a mono-eomponent. Modification to the original model was made by splitting SOC pool into two components of light fraction （LF）and heavy fraction （HF）. Decomposition of LF and HF pool was simulated by a first-order kinetics equation, and the first-order decay rate was positively correlated to SOC density. The modified and the original model were validated against independent data sets with temporal and spatial difference. Model validation indicated that the modified model is capable of simulating the changes in LF and HF pool and can well capture the changes in SOC when the marshland was converted into cropland. A further simulation suggested that significant SOC loss occurred in the early several years after marshland conversion was greatly attributed to a rapid decomposition of LF pool with higher first-order decay rates, while the original model could not capture the signal due to a lower first-order decay rate.