Soils of the European Union - European Soil Portal - Europa

4.9 FluvisolsGeographical distributionFluvisols cover areas over 220,000 km 2 , thus more than 5% of the total land area of the European Union. Fluvisols arepresent in nearly all regions, forming dominant soil reference group in 1,532 cases, being associated soil in 704 and asinclusions in 997 soil associations (of the continental scale assessment).Seven different subgroups contribute to the Fluvisol coverage of the European Union, with Eutric Fluvisols and CalcaricFluvisols having the largest shares, together covering more than 90% of the Fluvisol lands. (Table 4.9, Figure 4.9)Table 4.9 Area of the second level units of FluvisolsUnits in the Reference Soil Groupin the EUCodes ofsoil unitsArea in the EUkm 2Calcaric Fluvisol FLca 97224Dystric Fluvisol FLdy 6600Eutric Fluvisol FLeu 108733Gleyic Fluvisol FLgl 7854Haplic Fluvisol FLha 65Mollic Fluvisol FLmo 936Thionic Fluvisol FLti 257Apart from Italy and the Central-North and North Easter quarter of the EU, Calcaric Fluviols occur in all of its regions.Dystric Fluvisols are less frequent; however they are present throughout the continent. Eutric Fluviols, the mostwidespread soil unit has its largest continuous coverage in the Po plain in Italy. Gleyic Fluvisols are characteristic for riverbasins in Poland. Haplic and Thionic Fluvisols are associated to other Fluvisols in southern England while the Mollictypes can be found in Slovakia.0.03% 0.42% 0.12% FLca3.54%FLdyFLeuFLglFLhaFLmo43.86%49.05%FLti2.98%Global referenceFigure 4.9 Share of the second level soil units in the area of FluvisolsFluvisols are common in periodically flooded areas such as alluvial plains, river fans, valleys and tidal marshes, on allcontinents and in all climate zones. They occupy some 3.5 million km 2 worldwide, of which more than half are in thetropics.Fluvisols are young soils that have fluvic soil properties. For all practical purposes this means that they receive freshsediment during regular floods (unless the land was empoldered) and (still) show stratification and/or an irregular organicmatter profile. Fluvisols in upstream parts of river systems are normally confined to narrow strips of land adjacent to theactual riverbed. In the middle and lower stretches, the flood plain is wider and has the classical arrangement of levees andbasins, with coarsely textured Fluvisols on the levees and more finely textured soils in basin areas further away from theriver. Fluvisols show layering of the sediments rather than pedogenic horizons. Their characteristics and fertility depend onthe nature and sequence of the sediments and length of periods of soil formation after or between flood events.Common international names of Luvisols include Alluvial soil, Fluvents (Soil Taxonomy) and Auenböden (Germany).28