Water and gas transfer in porous media like soils are determined by their porous network, described by their
structure. In soil, the horizon is usually considered to be elementary and homogeneous functioning system in
the description of gas and water functioning. However, in some cases, a horizon is heterogeneous, and its
structure is defined by the 3D arrangement of Elementary Pedological Volumes (EPVs). The horizon needs to
be described in three dimensions to improve the characterisation of the structure and, consequently, the
prediction of its hydraulic functioning. The aim of this study was to determine the feasibility of describing the
3D structure of a heterogeneous albeluvic tonguing soil horizon composed of a juxtaposition of silty white and
clayey ochre EPVs, using 3D electrical resistivity tomography (ERT). Electrical measurements were compared
with geostatistical analyses from soil photographs. We demonstrated that the resistivity of the white EPVs was
greater than that of the ochre EPVs. In addition, the general soil structure and organisation of the soil horizon
could be derived from the electrical resistivity data. We proposed a method to discretise the soil electrical
resistivity into a binary system that corresponded to white and ochre volumes. Finally, a 3D representation of
the soil structure was created that could be used to improve soil hydraulic models