Page 43 - World Reference Base for Soil Resources of Thailand
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Land Development Department Library
Arenosols
Definition
Arenosols have a texture that is coarser than sandy loam to a depth of at least 100 cm
from the surface, or to a plinthic, pertroplinthic or salic horizon and having less than 35%
(by volume) of rock fragments. Ochric, yermic, albic, plinthic, petroplinthic, or salic horizons are
the only diagnostic horizons found in Arenosols.
Distribution
Arenosols occur on deep aeolian, marine, lacustrine and alluvial sands. The total extent
is approximately 5.6 billion rais, mainly desert regions of Africa, and in Western Australia and
South America. They are frequently associated with Leptosols, Regosols, Calcisols, Solonchaks,
and Podzols.
In Thailand, these soils cover countrywide about 6.4 million rais, mostly distributing in
the northeast, east, and south.
Formation
Arenosols are developed from the parent materials with coarse texture. A weak
accumulation of organic matter characterizes the surface orchic horizon in semi-arid areas. In the
humid tropics, under intensive vegetation, cheloviation contributes an extremely deep albic horizon
developing well below the depth, which would classify these soils to inclusion with the Podzols.
Profile features
In the humid tropics, Arenosols may give the thick albic horizon of the “giant podzol”
(Albic Arenosol) to a depth of 12 m. Other profiles may overlie plinthic or petroplinthic horizons and
are much shallower.
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