Ferralsols

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.

Clayey Ferralsol derived from basalt, China; residual iron gives the soil its dark reddish brown colour (Rhodi-Geric Ferralsol; ISRIC reference soil CN 018)

Ferralsol with accumulation of plinthite in the lower part of the profile, Brazil (Endoplinthic Ferralsol)