Classification of alluvial soils - problematic issues on the examples from South Baltic Lakelands, north Poland

Abstract

Alluvial soils constitute a group of soils that is very diverse in terms of their genesis and what is the effect of it -most of properties, e.g. organic carbon content, features connected with ground or stagnating water, development of B horizons or texture. It is also refl ected in their systematic position. Currently, the Polish Soil Classifi cation (PSC, 2019) distinguishes as many as 3 types of soils developed from fl uvic materials: ordinary, chernozemic and brown alluvial soils. Some of soils with alluvial sediments strongly infl uenced by water but without diagnostic horizons can be also classifi ed as gleysols or stagnosols. The aim of the article was to check the criteria and to verify completeness of units in the rank of types and subtypes for distinguishing alluvial soils in latest version of Polish Soil Classifi cation (PSC, 2019). The study was carried out in area covered by Vistulian glaciation in Northern Poland. 87 profi les to the maximum depth of 210 cm were studied. 18 pedons belong to chernozemic alluvial soils, the most common type (48) was classifi ed as brown alluvial soils, ordinary alluvial soils occurred 11 times. Moreover, 7 pedons with fl uvic material were classifi ed as gleysols. Other 3 soils represented organic and colluvial soils. Based on the conducted research some changes in Polish Soil Classifi cation have been proposed. They are regarding the minimum thickness of fl uvic materials for classifying alluvial soils, the revision of the humus subtype, the introduction of the type of gleyzemic alluvial soils in gleyzemic order or subtype of alluvial soils in type of gleysols and subtype of waterlogged soils in chernozemic alluvial soil type. The article also addresses important issues of the origin and classifi cation of B horizons in the studied soils, and confi rmed signifi cant usefulness of soil-agricultural maps in determining the places of occurrence of alluvial soils.