Geoscience Reference
In-Depth Information
Table 4.13 Contd...
Isofrigid
- the same subdivisions are found but without
great difference in temperature between summer
and winter
Isomesic
- same as above
Isothermic
- same as above
Isohyperthermic
- same as above
Sulfidic
Contains sulphides
Sulfuric
Contains sulphates
Table 4.14
Key for determining the Orders of Soil Taxonomy (with very
approximate equivalents in WRB language).
Order
Suffix WRB equivalent Brief definition
Gelisols
els
Cryosols
(Gr.
gelid
= very cold) Have permafrost
on the surface or at least within 200
cm depth (
immature soils of high altitudes
and latitudes
)
Histosols
ists
Histosols
(Gr.
histos
= tissues) Present a thick
(>40 cm or more than 2/3 of the soil
thickness if it is thin) organic horizon,
accumulation related to the current or older
presence
of water (
peats and highly organic
soils
)
Spodosols
ods
Podzols
(Gr.
spodos
= ash) Present a spodic horizon
Andisols
ands
Andosols
(Japanese
ando
= black) Have andic
properties (
typical soils of volcanic regions if
the environment is humid and cool or cold
).
Order introduced in the 4th edition.
Oxisols
ox
Ferralsols
(from oxide) Present an oxic horizon (less
than 10% weatherable minerals in the
50-200
m
m fraction, presence of
sesquioxides of Fe
2
O
3
or Al
2
O
3
type, cation
exchange capacity less than 16 cmol (+) kg
-1
clay or presence of a kandic horizon:
fine texture, relative enrichment in clay, low
cation exchange capacity
Vertisols
erts
Vertisols
(L.
vertos
= to turn
⇒
shrinking soils) Present
slickensides or at least peds with oblique
faces, more than 30% clay and shrinkage
cracks during the dry period (
Vertisols of dry
Mediterranean or subtropical climates
)
Table 4.14 Contd...
