Cutans: their definition, recognition, and interpretation.

Summary The term cutans is proposed for a broad group of pedological features, including so-called‘clay skins’, associated with the surfaces of the skeleton grains, peds, and various kinds of voids within soil materials. The chief differentiating characteristics of cutans are the kind of surface with which they are associated, the mineralogical nature of the cutanic material, and the fabric of the cutans themselves. Cutans can be interpreted on the basis of their characteristics in terms of the genetic processes of soil formation, and classified into simple and compound groups, each of which can be sub-divided into illuviation, diffusion, and stress types, composed of particular materials. The effects of cutans on profile development and plant growth may be considerable and their characteristics may dominate the characteristics of the soil material.