Ferralsols

 
Distribution of Ferralsols (FAO, GIS) (click to view larger picture)

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.

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

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