The contribution of volume scattering from the subsurface stratum of soil or snow to the backscattered radar signal decreases rapidly with increasing moisture content as compared to the contribution by rough-surface scattering. In order to obtain an evaluation of the relative importance of volume scattering of moist strata, a heterogeneous two-component mixture of water inclusions in a dry background medium is assumed and the formulation of the distorted Born approximation according to Tsanget al.is applied. Computed permittivities and backscatter cross-sections are compared with experimental data of situations with modest moisture content. From there, conclusions on the relative portion of volume scattering and on shape and size of the effectively-scattering water inclusions can be drawn.