Reference soil Ecuador 06:
Ferralsols occur in tropical and subtropical regions of the world, mainly on old and stable land surfaces.
Characteristics
Soils having a ferralic horizon (strongly weathered horizon with low-activity clays and very low amounts of weatherable minerals) between 25 and 200 cm from the soil surface. They lack a nitic horizon (a horizon with strongly developed, nut-shaped structure) and do not have a layer which fulfils the requirements of an argic horizon and which has, in the upper 30 cm, 10 percent or more water-dispersible clay.
Road cut observations show different (completely weathered) parent materials like conglomerate, clay(stone?),.. The subsoil shows a weak yellowish mottling probably due to redox processes. The soil shows clear narrow cracks when dry. The soil is well structured which agrees with the classification as Nitosol. If the morphology is not taken into account it will come out as ferric Acrisol.
WRB 2006
Vetic Acric Ferralsols (Alumic Clayic ) |
20-150 | argic horizon |
18-150 | ferralic horizon |
WRB 1998
Acric Veti Alumic Ferralsols |
18-150 cm | ferralic horizon |
20-150 cm | argic horizon |
0-18 cm | ochric horizon |
FAO-UNESCO-ISRIC 1974
Dystric Nitosols |
- | ferric horizon |
0-42 cm | ochric A horizon |
20-150 cm | argillic B horizon |
Local classification
Classification information | Suelo Rojo |

USDA-SCS (1975) | Paleudult perudic clayey isohyperthermic |
Napo, Francisco de Orellana, 12km S of Coca