Soils of the European Union - European Soil Portal - Europa

4.17 PlanosolGeographical distributionDespite of their fairly widespread geographical distribution throughout the continent, Planosols have a relatively smallshare (< 0.5%; < 20,000 km 2 ) among the soil types of the European Union.Three different subgroups contribute to the Planosol coverage of the European Union. However, Haplic units only accountfor a very small area (Table 4.17, Figure 4.17)Table 4.17 Area of the second level units of PlanosolsUnits in the Reference Soil Groupin the EUCodes ofsoil unitsArea in the EUkm 2Dystric Planosol PLdy 9379Eutric Planosol PLeu 9434Haplic Planosol PLha 167Dystric Planosols are dominant in 56 soil units, associated to 150 and have inclusions in 48 throughout the continent. Themost typical profiles can be found in Austria. Main areas of Eutric Planosols include regions in Estonia, Austria andBulgaria but further eight counties contain this unit among their soil resources. Haplic planosols are inclusions in 40 soilassociations, all in southern regions of England.0.88%49.70% 49.42%PLdyPLeuPLhaGlobal referenceFigure 4.17 Share of the second level soil units in the area of PlanosolsPlanosol areas of the earth can be found mainly in subtropical and temperate regions with clearly alternating wet and dryseasons. Their global coverage is estimated at around 1.3 million km 2 .Planosols are soils with bleached, light-coloured, eluvial surface horizons that show signs of periodic water stagnation andabruptly overly dense, slowly permeable subsoil with significantly more clay than the surface horizon. They developmostly on clayey alluvial and colluvial deposits, predominantly in flat lands but can also be found in the lower stretches ofslopes, in a strip intermediate between uplands, e.g. with Acrisols or Luvisols, and lowland (plain or basin) areas, e.g. withVertisols.Planosols have typically a weakly structured surface horizon over a horizon showing evidence of stagnating water. Thetexture of these horizons is markedly coarser than that of deeper soil layers; the transition is sharp and conforms to therequirements of an `abrupt textural change'. The finer textured subsurface soil may show signs of clay illuviation; it is onlyslowly permeable to water.Most Planosols are poor soils and are therefore not used as cropland but utilized for extensive grazing and forestry.Planosols were formerly known as pseudogley soils and today are dealt under different levels of classification hierarchiesin national and international classification systems.44