Abstract: | A modification based on capillary flow type was proposed for three theoretical infiltration equations accounting for the physical properties of the soil. The equations were (a) Green and Ampt, (b) Fletcher, and (c) Fok and Hansen. The derived modified equations were tested by computer programs on four undisturbed field soils on which the mass infiltration and soil properties had been measured. Of the three equations, (b) exhibited the best adherence to the data points and (a) and (c) were reasonably good. In general, the types of relations revealed by the field measurements were such as would tend to linearize if the log of the mass infiltration was plotted against the log of time. The breaks exhibited by some of the soils could be explained by changes in the soil properties at that point. |