非饱和土壤水分运动参数的测定(一)

应用能量观点研究非饱和土壤水分运动,测定土壤水分特征曲线不仅是研究土壤物理性质的重要环节,也是间接测定参数容水度C(θ)的重要方法。经5年试验:(一)不同质地土壤水分特征曲线不同,曲线坡度也不一样。粘土大于砂壤土;(二)在低吸力条件下,干容重愈大,曲线愈靠近座标轴右边;(三)土壤干湿过程不同,水分特征曲线也不同,测定水分特征曲线在生产上有实用价值。

Determining Parameter of Unsaturated SoiI Water Motion

Using the conception of energy to determine soil water chracter curve and to study unsaturated soil water mo-tion is not only an important Iink of studying the physicaI puality. but also an important method todeterminewatere con-taining parameter indirectIy. Tensiometer method is used commonly. The principle is: water potentiaI outside the instru-ment is the same as it is inside, and the number showed in negativediaI of tensiometer is matric potentiaI. The particular method was: clay and sand sampIes seIected in test tube(inside diameter is 23cm, height is 30cm.)were determined, and a water cheracter curve from moisture to dryand from dry to moisture was obtained. The experimental result of five years is: 1.)The watercharacter curves of defferent soil are different, and the curve slopeis different, curve slope of clay is bigger than of sand. 2.) Under the condition of low suction, the bigger the dry capacity is, the nearer the curve to the right of axis. 3.)The courses of soil to be dried or moistened are different, the water character curves are different.Determining water character curve is very useful for production practice.