AbstractCorresponding values of flow velocity and moisture gradient were calculated for water flow in unsaturated soil, using a graphical analysis of moisture profiles obtained during horizontal absorption of water into air‐dry Salkum silty caly loam. Plots of flow velocity vs. moisture gradient were straight lines through the origin at the higher moisture contents, but Darcy proportionality did not hold at the lower moisture contents.The observed deviations were of the same type as found in earlier studies for plots of flow velocity vs. hydraulic gradient for water‐saturated materials containing clay, and could be fitted by a modified flow equation developed previously for the water‐saturated materials. Physically, the non‐Darcy behavior is tentatively attributed to non‐Newtonian liquid effects caused by clay‐water interaction.Consideration of diffusion‐type analysis from the stand‐point of non‐Darcy behavior shows that the diffusivity D becomes a function of moisture gradient w as well as moisture content θ. This provides a way of accounting for the nonuniqueness of D(θ) recently reported in the literature.