Page 50 - E-BOOK English
P. 50
Cambisols
Definition
Cambisols have a cambic or a mollic horizon overlying a subsoil with a base saturation
of < 50%.
Distribution
Cambisols worldwide cover more than 9,375 million rais, especially in the temperate
regions. Associated soils include Gleysols, Leptosols, Fluvisols, Acrisols, and Ferralsols.
In Thailand, Cambisols regionwide distribute about 6 million rais, dominated in the
northeast, particularly in Roi Et, Yasothon, and Amnat Charoen provinces.
Formation
The subsurface horizon of Cambisols has been changed in colour and structure so that
it is clearly different from the parent material. The primary soil-forming process responsible for
the cambic horizon is in situ alteration. Free carbonates are typically removed from the profile,
and wetting/drying cycles create the colour and structural differences.
48
