基于保水剂应用的土壤水分运移模型构建方法及源汇项求解

The Construction Method for Soil Water Transport Model and Its Source-sink Term Solving Based on the Application of Superabsorbent Polymers

保水剂作为一种重要的非工程节水材料,已在旱地农业生产中得到了广泛应用,但适用于保水剂应用条件下的土壤水分运移模型还不多见。本文对保水剂应用条件下的土壤水力参数进行了重新定义,将非饱和扩散率D(θ)及非饱和导水率K(θ)分别表示为时变函数形式D(θ,t)和K(θ,t),在前人研究的基础上,对保水剂施入土壤中的时间和试验进行时间进行了统一,提出了适用于保水剂应用条件下的土壤水分运移模型构建方法及其源汇项求解方法,同时设置了数值试验对源汇项求解方法进行了检验。结果表明:时间步长、土壤层状性及边界条件对源汇项求解方法稳定性的影响较小,而时间间隔、水力参数、测试误差和仪器精度对稳定性的影响较大。

As important materials used in non-engineering water saving ,superabsorbent polymers（SAP） are widely applied in dryland agriculture .However ,there are few reports on soil water transport model under the condition of superabsorbent polymers applica‐tion .In this paper ,soil hydraulic parameters D（θ） and K（θ） were redefined by time-varying function D（θ,t） and K（θ,t） ,respec‐tively .On the basis of previous studies ,the residence time of SAP in the soil and the duration of the experiment were harmonized . The construction method and its source sink solving method working for SAP application was proposed ,and numerical testing was carried out to examine the source-sink term solving method .The results show that the time step ,layering of soil and boundary condi‐tions had little effects on the stability of the solving method ,but time interval ,hydraulic parameters ,test errors and instrument pre‐cision had an obvious effect on the stability .