World’s Soil Resources

6 | Soils with accumulation of moderately soluble salts
DURISOLS (Durids)
Durisols may develop in arid and semi-arid conditions when a dissolution and accumulation of silica leads
to the formation of a cemented hardpan that restricts the rooting depth of soils. These soils form mainly in
alluvial and colluvial deposits in level or slightly sloping alluvial plains, terraces and piedmont plains. Stable
landscapes occur where the Durisols have been eroded down to their resistant duripan, the material of which
is often used in road construction. Durisols in low-lying areas may suffer from salt accumulation (Figure A 22).
The duripan may range in thickness from 10 cm to more than 4 metres. There are two main types of duripans:
those which are massive, and those with a platy or laminated structure that are coated with amorphous opal
or microcrystalline silica.
Durisols are known to be relatively extensive in Australia, South Africa, Namibia and the drier parts of the
southern United States. Minor extents have been observed in South America and Kuwait. No estimate of their
global extent is available (FAO, 2014). The agricultural use of Durisols is mostly limited to extensive grazing.
Arable cropping is limited to areas where irrigation water is available.
Status of the World’s Soil Resources | Main Report Annex | Soil groups, characteristics,
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distribution and ecosystem services