Planosol

thumb|Haplic Planosol profile near Abiy Addi in [[Ethiopia]] thumb|right|400px|Distribution of Planosols thumb|Soil profile of a Eutric Planosol A Planosol in the World Reference Base for Soil Resources is a soil with a light-coloured, coarse-textured, surface horizon that shows signs of periodic water stagnation and abruptly overlies a dense, slowly permeable subsoil with significantly more clay than the surface horizon. In the US Soil Classification of 1938 used the name Planosols, whereas its successor, the USDA soil taxonomy, includes most Planosols in the Great Groups Albaqualfs, Albaquults and Argialbolls.

==Occurrence== These soils are typically in seasonally waterlogged flat lands. They occur mainly in subtropical and temperate, semi-arid and subhumid regions. Planosols are formed mostly in clayey alluvial and colluvial deposits. Geological stratification and/or a pedogenetic process of destruction and removal of clay has resulted in the relatively coarse-textured, light-coloured surface soil abruptly overlying finer textured subsoil; impeded downward percolation of water causes temporarily reducing conditions with a stagnic colour pattern, at least close to the abrupt textural change.