The term deluvial is applied to a deposit formed as a result of geodynamic processes in hilly and undulating landscapes by natural and technogenic movement of topsoil or products of weathering down the slope and its accumulation. The properties and distribution of deluvial soils are important for agriculture history, soil erosion and water protection.

Deluvial soils are part of national soil classification systems of Poland and until 1999 of Lithuania. In Poland, deluvial soils are one of two orders within the fifth division – alluvial and deluvial soils. Later (Mažvila ir kt., 2003; 2006), deluvial soils in Lithuania have been groused in one unit with Cambisols and Fluvisols. In France and Germany, the soils on similar deposits are distinguished as Colluvisols.

Deluvial soils are mapped, and it is necessary to distinguish them in the first level of classification and to formulate the diagnostic properties of deluvial horizon or deluvial material.

Propositions for the diagnostic properties of Colluvisols are given on the base of selected properties of deluvial soils in Poland and Lithuania: thickness of more than 30 cm, very fine stratification and irregular distribution of organic carbon, organic carbon content more than 0.5% (of any thicker than 30 cm part of deluvial layer) as well as location on the bottom part of slope in hilly and undulating landscape.

Keywords: erosion, deluvial soils, colluvic material, texture, organic carbon, soil classification, WRB