Geoscience Reference
In-Depth Information
Table 4.11
Specific diagnostic characteristics of mineral soils.
Characteristic
Abbreviation
Simplified definition
Abrupt textural
Large increase in clay content over a short
change
distance
Albic materials
alb
(L.
albus =
white) material depleted of colouring
agents (clay, iron) and the colour of which is
that of sands and silts composing it
Andic soil
and
Contains allophanes, imogolite, ferrihydrite,
properties
Al-humus complexes (amorphous in the broad
sense); characterized by volcanic glass, the
presence of which does not lead to
classification of the soil as an Andisol
Anhydrous
(Gr.
anudros =
waterless), characterizes the cold
conditions
deserts with no liquid water
Coefficient of
Also called COLE; defined at the level of an
Linear Extensibility
aggregate by:
(Lm - Ld)/Ld
where Lm = length when moist (33 kPa tension)
Ld = length when dry
Durinodes
duri
(L.
durus =
hard), concretions with concentric
structure, more or less indurated, of size >
1 cm, silica-based
Fragic soil
frag
(L.
fragilis =
fragile), characterize a fragipan
properties
that does not have the required thickness or
size of constituents for satisfying the definition
of this diagnostic horizon (MUCH USED)
Identifiable secondary
Characterizes different forms of secondary
carbonates
carbonates: masses, nodules, concretions,
coatings
Interfingering of albic
Albic material penetrating more than 5 cm, in
materials
the form of fingers, in an argillic or natric hori-
zon below, representing in all less than 15%
by volume of the invaded part of the horizon
Lamellae
Illuvial horizons less than 7.5 cm thick separ-
ated by eluvial horizons, the lamellae correspon-
ding to a cambic or argillic horizon (banded
B in French)
Linear Extensibility
The COLE multiplied by the thickness of the
horizon, a measure of the potential of the soil
to swell and shrink
Table 4.11 Contd...
