The phenomenology of flow and transport in soil at a given scale is considered to be a consequence of the underlying heterogeneity of material properties at the smaller scale.

In this contribution, various attempts to get a quantitative relation between subscale structure and large scale behavior are discussed and evaluated. At the pore scale the (size) distribution function of pores and their topology greatly determines the large scale hydraulic and transport behavior. Analogously, at the larger scale, the distribution function of different materials and their topology are found to be the constitutive properties.

A quantitative understanding of the relation between the subscale structure and transport processes in soil opens promising links to other related disciplines as pedology, soil biogeochemistry and soil management.