中文摘要：

将土壤供水头压力控制为负值，测定了垂直入渗、毛管上升和水平入渗3种情况下的土壤吸水过程，发现随供水吸力的增加，垂直入渗、毛管上升和水平入渗过程中湿润蜂前进速度和入渗速度的相对差异变小。将入渗速率等于潜在蒸发速率时的湿润厚度定义为临界湿润厚度，计算了潜在蒸散率为5mm／d时不同负水头下壤土的临界湿润厚度；确认了垂直、毛管和水平入渗下湿润蜂位置与入渗量的关系，将湿润蜂位置-累计入渗量曲线的斜率，即已湿润土体内入渗水分所占的容积百分数定义为湿润系数，提供了所测壤土的湿润系数-负水头曲线；建立了负水头供水过程中土壤含水量空间分布模型；观察到湿润锋含水量与供水吸力间的依赖关系。

英文摘要：

Hydraulic head of supply water is maintained at negative values and vertical infiltration, capillary rise, and horizontal infiltration processes were observed. With increasing water supply tensions, relative differences of vertical infiltration, capillary rise, and horizontal infiltration processes in infiltration rates and wetting front movement speed decreased. The wetting depth at which infiltration rate is equal to potential evapo-transpiration rate is defined as critical wetting depth, and critical wetting depths at different negative hydraulic heads were obtained for the studied loamy soil by setting potential evapo-transporation rate at 5 mm/d. Linear relationships between wetting depth and cumulative infiltration amount for vertical infiltration, capillary rise, and horizontal infiltration were validated. The slope of wetting depth-cumulative infiltration, i. e. , percentage of wetted soil volume occupied by infiltrated moisture, was defined as wetting coefficient, and the relationships between wetting coefficient and supply hydraulic head were provided for the studied loamy soil. A model describing soil moisture profile for vertical infiltration, capillary rise, and horizontal infiltration under negative supply hydraulic head was provided. The reliance of wetting front water content on supply hydraulic head was also demonstrated.