非饱和土壤水分运动参数的确定——以昆明红壤土为例

应用数学物理方法对降雨入渗、产流等水量转化关系模拟时,土壤水分运动参数即土壤水分特征曲线、扩散率、导水率是必不可少的数据,影响和控制着水及溶质在土壤和地下水中的分布和运移速度,是描述和研究土壤水运移的关键参数.以昆明地区红壤为例,利用离心机测定土壤水分特征曲线、水平土柱测定扩散率并计算出导水率,利用VG公式拟合土壤水分特征曲线,通过指数经验公式拟合土壤水体积分数与扩散率、导水率的关系,结果表明具有显著的相关性.在参数确定过程中,充分考虑了颗粒粒径、干容重等影响,得到了最优的土壤水分运动参数,为相关研究提供一定的参考.

Parameters of unsaturated soil moisture movement: a case study of red soil in Kunming

Water dynamic parameters such as soil water characteristic curve,unsaturated diffusivity and hydraulic conductivity are required in theoretical simulation of rainfall in filtration,runoff and other relationship of water transformation.Distribution and migration rate of water and solute in soil and groundwater are key parameters to investigate soil water transport.For red soil in Kunming for example,soil water characteristic curve is ascertained by centrifugation,and fitted in Valentin-Guiochon equation.Unsaturated diffusivity is determined by Horizontal Column,hydraulic conductivity is calculated.Relationships between volumetric water content,diffusivity and hydraulic conductivity are fitted by exponentially empirical formula.With fully considered grain diameter,dry density and other factors,optimal parameters of soil water movement are obtained,these being useful references in related research.