以川中丘陵区紫色土为研究对象, 采用圆盘张力入渗法, 测定坡耕地和林地土壤在5个水头下(0、-1、-3、-6、-9cm)的导水率曲线, 并对比分析野外圆盘张力入渗法和环刀土样室内降水头法测得的土壤饱和导水率的差异。结果表明, 土壤稳定入渗率和非饱和导水率随负压绝对值的增大而降低, 且坡耕地的变化幅度大于林地。野外圆盘张力入渗法测得的饱和导水率明显高于环刀土样降水头法的测定值。基于研究结果, 推荐使用圆盘张力入渗法测定导水率曲线和饱和导水率。

Using a disc tension infiltrometer,infiltration experiments were conducted to measure soil hydraulic conductivity curve under different tensions(0,-1,-3,-6,-9cm)and different land uses on purple soils of hilly southwestern Sichuan,China.The differences of saturated hydraulic conductivity determined by both disc tension infiltrometer experiment in the field and falling head method on soil ring samples in the laboratory were comtrasted and analyzed.The results showed that the soil infiltration rate decreased quickly with increasing absolute value of applied tension,which was more significant in cultivated soils than in forest soils.The observed values of Ksusing the disc tension infiltrometer were higher than those obtained using the falling head method on soil ring samples.Therefore,the use of a disc tension infiltrometer for determination of hydraulic conductivity curve at or near saturation and saturated conductivity is recommended in this study.