Water characteristic functions of 351 undisturbed soil cores taken at three profiles on a two-dimensional regular grid with a spacing of 0.15 m are shown to vary linearly and nonlinearly in space. To describe their heterogeneity, linear and nonlinear scaling factors are independently derived with soil horizons as separate similarity classes. Their estimated empirical distributions are different, and the spatial statistics show a comparable integral scale only in the horizontal direction (~0.15 m). In the vertical direction, nonlinear scaling factors exhibit an integral scale of ~0.2 m, and linear scaling factors exhibit a pure nugget effect. On a small sample subset, other soil material properties (e.g., texture) were also analyzed. In a multiple linear regression between those material properties and scaling factors the organic carbon content is a significant deterministic factor at the site. ¿ 2000 American Geophysical Union