ABSTRACT Partial analysis in the form of limiting analytical solutions is applied to the problem of infiltration into a semi-infinite column at constant initial moisture content. It is found as a result of such an analysis that: (a) the solutions for realistic assumptions concerning the soil moisture characteristics are bounded reasonably closely by an upper limit corresponding to constant diffusivity and ultimate infiltration rate equal to saturated conductivity and a lower limit corresponding to constant diffusivity and zero conductivity; (b) for both of the limiting cases of zero horizontal conductivity and infinite horizontal conductivity, the values of average sorptivity are insensitive to the form of the statistical distribution of spatial non-homogeneity; (c) the average sorptivity is less than the corresponding sorptivity based on the average scale parameter of a spatially variable soil and the average ultimate rate of infiltration is greater than the corresponding ultimate rate based on the average scale parameter.