žEMėS ūKIO MOKSLAI. 2008. T. 15. Nr. 3. P. 29–35 © Lietuvos mokslų akademija, 2008 © Lietuvos mokslų akademijos leidykla, 2008 Properties of deluvial soils in Poland and Lithuania and propositions for their classification Ieva Baužienė 1 , Marcin Świtoniak 2 , Przemysław Charzyński 3 1 Department of Landscape Geography and Cartography, Institute of Geology and Geography, T. Ševčenkos 11, LT-4324 Vilnius, Lithuania E-mail: ieva.bauziene@geo.lt 2 Department of Soil Science, Institute of Geography, Faculty of Biology and Earth Sciences, Nicolaus Copernicus University, 87-100 Torun, Gagarina str. 9, Poland E-mail: swit@umk.pl 3 Department of Landscape Geography, Institute of Geography, Faculty of Biology and Earth Sciences, Nicolaus Copernicus University, 87-100 Torun, Gagarina str. 9, Poland E-mail: pecha@geo.uni.torun.pl e 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 weather- ing down the slope and its accumulation. e 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 fiſth 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 clas- sification 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. Key words: erosion, deluvial soils, colluvic material, texture, organic carbon, soil clas- sification, WRB INTRODUCTION e term ‘deluvial’ is applied to deposits formed as a result of geodynamic processes in hilly and undulating landscapes by the natural and technogenic movement of topsoil or products of weathering down the slope and their accumulation. e concept of deluvium and deluvial soils was used by famous Russian scientists A. P. Pavlov, V. V. Dokuchaev (Доку- чаев, 1950; Павлов, 1888) and others. Instead of diluvium, the concept of colluvium is used in most European countries and in the American soil science. At first, the concept of deluvium (colluvium) was used for the definition of mainly water erosion sediments, but aſter World War II the intensification and mechanization of agriculture led to a high acceleration of erosion. Tillage erosion on arable land can represent up to 50% of total sediment transport (van Oost et al., 2000). erefore, in scientific literature of the early 20th century, the notion ‘deluvial processes’ was used for the definition of the processes that have formed silt-rich surface sediments in extraglacial zones of the Pleistocene period. Recently, it has been proposed to call these sediments as loess and loess-derived material (Švedas, 2003). us, the definition of sediments in the extraglacial zones of the Pleistocene period as ‘deluvial’ is an inaccuracy. Investigations concerning formation and characteristics of deluvial soils are very important for understanding the human impacts on geomorphic processes in agricultural landscapes and the geomorphic evolution. e common occurrence of deluvial soils is the main reason for their distinguishing as distinct units (on different levels of classification) in many regional soil classification systems. Deluvial soils had been part of national soil classification systems of Poland and Lithuania (until 1999). In France and Germany, soils on similar deposits are distin- guished as colluvisols (Почвенный…, 2000). Human-modified soils in the modern Russian soil classifica- tion are classified into a common unit with natural soils in the