一维代数模型在重度盐碱土微咸水灌溉中的适用性

Applicability of one dimensional algebraic model in brackish water irrigation of severe saline-alkali soil

为了验证一维代数模型对微咸水在重度盐碱土入渗的适用性,以重度盐碱土为研究对象,设置不同矿化度水平(2,3,4,5 g/L)的微咸水进行室内垂直一维积水入渗试验.利用湿润锋和入渗率、湿润锋和累积入渗量之间的关系推求模型参数,对入渗历时和土壤剖面含水率进行数值模拟,采用符合度指数和均方根误差评价模型适用性.结果表明,入渗历时的均方根误差RMSE均小于6.7 min,入渗历时模型的符合度指数D均超过0.99;含水率的均方根误差RMSE小于3.5%,含水率模型的符合度指数D均在0.90以上;说明一维代数模型能够有效地描述微咸水在重度盐碱土中的入渗过程,对入渗结束后土壤剖面上水分分布情况具有较高的模拟精度.

In order to verify the applicability of one dimensional algebraic model in brackish water irrigation of severe saline - alkali soil, one dimensional infiltration experiments are conducted in laboratory on saline -alkali soil with different levels of mineralization degree （2, 3, 4 and 5 g/L）. The model parameters are decided by means of experimental relationships between infiltration rate and wetting front as well as cumulative infiltration. Then infiltration time history and moisture content of soil profile are simulated numerically with the model. The root mean squared error （RMSE） and the index of agreement （D） are chosen to evaluate the applicability of the model. The results show that all the RMSE of infiltration time is less than 6.7 rain; all the than 0.99. All the RMSE of water content is 〈 3.5% ; D produced by infiltration time model is more all the D produced by water content model exceeds 0. 90. This process of severe suggests that one dimensional algebraic model can effectively describe the infiltration saline - alkali soil, this model also can simulate water distribution in soil profile more accurately after an infiltration ends.