Andosols are soils of active volcanic areas. They exhibit unique soil properties that place them apart from other soils. The term ‘andosol’ is derived from Japanese, ‘an’ meaning dark, and ‘do’ connotating soil (Figure A22). Andosols are also found outside active volcanic regions when environmental conditions favor their formation. Andosols have a limited extent (1–2%) of Earth's land surface, but many such areas are densely populated.
Andosol in Iceland. The profile is about 190 cm thick. Many distinct tephra layers are evident, disturbed by cryoturbation. Basaltic and andesidic tephras are dark, but thin light colored rhyolitic tephras are also seen near the middle and near the bottom of the profile. The soil contains considerable carbon in most horizons, also at depth.
The discussion of this entry follows the terminology of the World Reference Base for Soil Resources (WRB, FAO, 1998). Andosols are termed slightly different, or andisols according to ...