冬小麦不同深度灌水条件下土壤水分运动数值模拟

冬小麦深度灌水可以促进根系深扎,提高水分利用率。为了定量计算深度灌水条件下土壤水分动态,根据冬小麦不同深度灌水试验,用土壤水分运动方程的源项模拟不同深度灌水,建立了冬小麦不同深度灌水条件下土壤水分运动模型,采用有限差分法求解。利用不同深度灌水冬小麦试验数据对模型进行验证,结果表明模型计算的土壤含水率与实测土壤含水率的动态变化趋势一致,二者显著相关,相关系数在0.90以上,模型平均绝对误差最大值为0.023 cm3/cm3,平均相对误差最大值为8.22%,均方根误差最大值为0.03 cm3/cm3。所建模型具有较高的模拟精度,可用于模拟不同深度灌水条件下冬小麦土壤水分分布与动态变化。

Numerical Simulation of Soil Moisture Movement under Different Depths Irrigation for Winter Wheat

In northern China, drought and shortage of water resources are very serious and have seriously affected the production of winter wheat. Choosing a reasonable irrigation method to improve the deep soil water use efficiency is of great significance to water saving and efficiency increase of winter wheat. The deep irrigation of winter wheat can promote deep rooting and improve water use efficiency. In order to quantitatively calculate soil moisture dynamics under deep irrigation conditions, the soil water movement models under different depths irrigation of winter wheat was established based on different depths irrigation experiments of winter wheat and the source terms of soil moisture equations were used to simulate different depths of irrigation. The model was solved by the finite difference method. The model was validated by the experimental data of winter wheat at different depths of irrigation. The results showed that the soil water content calculated by the model was in accordance with the dynamic change trend of the measured soil moisture content. The simulated and measured soil moisture contents were significantly related, the correlation coefficient was greater than 0.90, the maximum absolute error of the model was 0.023cm3/cm3, the maximum of the average relative error was 8.22%, and the maximum value of the root mean square error was 0.3cm3/cm3. Therefore, the model had higher simulation accuracy and can be used to simulate the distribution and dynamic changes of soil moisture in winter wheat under different irrigation depths.