Entisols

Entisol
Entisol profile showing little or no evidence of pedogenic horizon development
Used in	USDA soil taxonomy

In USDA soil taxonomy, entisols are defined as soils that do not show any profile development other than an A horizon. An entisol has no diagnostic horizons, and most are basically unaltered from their parent material, which can be unconsolidated sediment or rock. Entisols are the second most abundant soil order (after inceptisols), occupying about 16% of the global ice-free land area.

In Australia, most entisols are known as rudosols or tenosols, whilst arents are known as anthroposols. In the FAO soil classification, because of the diversity of their properties, suborders of entisols form individual soil orders (e.g. fluvisols, lithosols).

Most fossil soils before the development of terrestrial vegetation in the Silurian are entisols, showing no distinct soil horizons. Entisols have been abundant in the paleopedological record ever since then, though, unlike other soil orders (oxisols, ultisols, gelisols for instance) they do not have value as indicators of climate - though orthents might in some cases be indicated of an extremely old landscape with very little soil formation (as in Australia today).