华东地区农田土壤有机碳动态模拟研究——模型的验证与灵敏度分析

以建成的农田土壤有机碳动态模拟模型为基础,增加土壤pH值影响函数,利用3组土壤pH值迥异的长期定位试验数据对模型进行验证。这些定位试验在地理位置、气象条件、农作方式和土壤性质等方面都具有较大差异。结果表明:修正后的模型可以较好地模拟不同pH值条件下土壤有机碳的变化趋势,模拟值和观测值间的线性相关系数(r2)为0.96(n=137);模型输入参数的敏感程度为温度>外源有机碳>土壤pH值>难分解组分初值>降水>土壤粘粒。

Modeling Farmland Soil Organic Carbon Dynamics in Eastern China: Model Validation and Sensitivity Analysis

The effect of pH on soil organic carbon(SOC) was added into a preliminary model that simulates farmland SOC turnover.The modified model was further validated against independent observations from three long-term field experiments with various climates,soils,cropping systems and agricultural managements.Model validation shows a fairly good agreement between the simulated and the observed changes in SOC,yielding a correlation coefficient r~2 of 0.96(n=137).Model sensitivity analysis indicated that the most and the least sensitive factors are temperature and soil clay content,respectively.The sensitive significance of the model to input parameters is in descending order of temperature,quantity of incorporated organic carbon,soil pH,initial value of resistant organic matter,precipitation and soil clay.