充分供水条件下点源入渗参数影响因素及其简化模型

以非饱和土壤水分运动理论为基础,建立了充分供水条件下点源入渗的土壤水分运动数学模型,并应用SWMS-3D软件对模型进行了求解,模拟并分析了充分供水条件下多种典型土壤的点源入渗特性及其影响因素。结果表明,充分供水条件下点源入渗累积入渗量曲线符合Philip模型;在相同土壤质地、容积密度下,吸渗率与稳渗率随着膜孔直径的增大而增大;稳渗率随灌溉水深的增大而略有增大。基于Philip模型,提出了包含膜孔直径、灌溉水深的充分供水条件下点源入渗简化模型。并利用黄土高原典型土壤的室内试验资料与已有文献资料对简化模型进行了验证。验证结果表明,所建简化模型能较简单地确定吸渗率和稳渗率,可较准确地反映充分供水条件下点源入渗特点。

Influencing Factors of Point Source Infiltration Parameters and Simplified Model Under Adequate Water Supply

Based on the theory for water movement in non-saturated soil,a mathematical model of point source infiltration under adequate water supply was established and solved by using SWMS-3Dsoftware.The point source infiltration characteristics were simulated with several typical soils under adequate water supply.According to the simulation results,the infiltration characteristics and related affecting factors was analyzed.It was shown that the cumulative infiltration curve can be well described using Philip model.With same soil texture and bulk density,the sorptivity(A)increased with film hole diameters.The steady infiltration rate(S)increased with film hole diameter and slightly increased with irrigation depth.Furthermore,the simplified infiltration model was proposed for point source infiltration under adequate water supply,including film hole diameter and irrigation depth as parameters.The simplified model was then tested by infiltration experiments using typical soils from Loess Plateau and experimental data reported in the studies of the other researchers.It was concluded that the simplified infiltration model accurately reflects the point source infiltration characteristics under adequate water supply and can therefore be applied readily to determine the sorptivity and steady infiltration rate.