Geoscience Reference
In-Depth Information
Many qualifiers only apply to a few cases. For example,
glacic
(systematically containing ice) obviously pertains to few soils of the
world. Thus the possible terminological combinations are not infinite.
The system is relatively simple, because the WRB defines the list of
prefixes and suffixes that can be applied to each RSG.
Figure 4.1 summarizes the ideas we have presented here.
39 diagnostic horizons
Definition
of 32
Reference
Soil Groups
(RSG)
14 diagnostic properties
12 diagnostic materials
157 major qualifiers (prefixes/
suffixes), if necessary
combined and refined by
'specifiers'
Definition of
the
lower level
Fig. 4.1
Principles of organization and use of the WRB, 2006 edition.
Many of the diagnostic horizons of the WRB are identical to those of
Soil Taxonomy examined later.
They are arranged in alphabetical order in Table 4.3, from left to
right, then top to bottom.
The diagnostic horizons
Table 4.3
The diagnostic horizons of the WRB.
Horizon
Simplified definition
Horizon
Simplified definition
Albic
White, depleted of iron
Anthraquic
Anthropic, compact, more
or less hydromorphic
Anthric
Cultivated
Argic
Clay-enriched B
Calcic
With accumulations
Cambic
Differentiated from the parent
of CaCO
3
material, this is the (B) of certain
authors
Cryic
Permanently frozen
Duric
Indurated by silica
Ferralic
With 1/1 clay minerals,
Ferric
Rich in segregations of iron, or
Fe and Al
mottles, not indurated
Folic
Organic material in
Fragic
Non-indurated but compacted,
aerated environment
prismatic structure
Fulvic
Brown; poorly crystallized
Gypsic
With accumulation of CaSO
4
minerals with organo-
mineral complexes
Table 4.3 Contd...
