不同地下水埋深土壤水分入渗规律研究

Study on Soil Water Infiltration Law under Different Water Tables

【目的】分析农田土水势的分布对作物的生长状况和农田水分循环的影响。【方法】采用观测室内层状长土柱(土柱长L=335 cm)在上边界条件为薄层积水、下边界控制不同地下水埋深时的水分入渗及蒸发过程的试验,分析了不同地下水埋深时土水势与零通量面的变化特征。【结果】入渗率随时间总的变化趋势是减小,入渗率随时间的变化一般经历3个阶段:迅速减小、缓慢减小和稳定阶段;累积入渗量随时间增加,与时间呈幂拟合关系;入渗初始阶段湿润锋运移速率较快,之后随着时间的推移,湿润锋运移速率逐渐减小,至某一时间后趋于稳定。【结论】湿润锋运移距离与时间的平方根呈线性关系.

【Objective】In order to analyze the influences of the distribution of soil water potential on total field water cycle and the growth condition of crops.【Method】A long soil column with length of 335 centimeters was used to observe the process of water infiltration and evaporation,in which the upper surface boundary condition was thin hydrops and the lower boundary condition was different ground water table.【Result】The research results are as follows:The infiltration rate was decreasing with time,which went through three periods:decreasing rapidly,decreasing slowly and being stable.The cumulative infiltration was increasing with time and had a power relation with time.3.In the initial period of infiltration,the transport velocity of wetting front was very fast.With the passage of time,the velocity decreased gradually and became stable to some time.【Conclusion】The transport distance of wetting front had a linear relation with the square-root of time.