ferrallitic

Ferrallitic is an adjective used in soil science to describe soils, horizons, or landscapes formed by ferrallitization, a weathering process characteristic of humid tropical climates in which silica and base cations are leached and iron and aluminium oxides and hydroxides accumulate.

Ferrallitic soils typically occur under intense rainfall, warm temperatures, and long soil development periods. They exhibit thick, deeply weathered profiles with a surface to subsoil layer rich in iron and aluminum sesquioxides, giving red or ochre colors. Base saturation is low, structure may be poor, and nutrient availability is often limited, especially for calcium, magnesium, potassium. Carbon contents can be variable; iron/aluminum oxide coatings may create durable horizons.

In agricultural and soil-ecology contexts, ferrallitic horizons are often associated with lateritic soils and, in some classification systems, correspond to ferralsols or oxic horizons. However, the exact usage varies; some older or regional classifications use ferrallitic to describe a broader set of intensely weathered, oxide-rich tropical soils, while modern schemes emphasize ferralsol and related oxidic soil groups.

Distribution includes tropical regions of Africa, South America, Southeast Asia, and parts of Oceania where high rainfall and long weathering produce lasting sesquioxide-rich profiles.