Geoscience Reference
In-Depth Information
The Americans grouped separately the diagnostic surface horizons or
Diagnostic Epipedons
(Table 4.9). These horizons are characterized by
names that are abbreviated if necessary.
The abbreviations are important because they serve to construct the
name of the soils. For example, there is a
Suborder
called 'Folist' that
goes back to the root 'Fol' of 'Folistic' defined in Table 4.9.
Epipedons (diagnostic surface horizons)
Table 4.9
Diagnostic surface horizons (epipedons).
Epipedon
Abbreviation
Simplified definition
Anthropic
Anthr
with traces of modification by man
Folistic
Fol
(from
L.
folia =
leaf), aerated medium, more than
15 cm, more than 8% organic C
Histic
Hist
(from
L.
histos =
tissue), wet medium, more than
20 cm, more than 8% organic C
Melanic
Melan
(from Gr.
melas =
black), black, more than 6%
carbon; exhibits (or is associated with) andic
properties
Mollic
Molli
Humiferous, dark, calcareous or non-acid, base
saturation > 50%, more than 10 cm thick
Ochric
Ochr
(from Gr.
ochros =
pale), very low C, poor in
CaCO
3
, light-coloured
Plaggen
Plag
More than 50 cm, man-made, typical signs
(pottery, spade cuts)
Umbric
Umbr
10 cm or more, dark coloured, base
saturation < 50%
The explanations given in Table 4.10 are brief and sometimes difficult to
understand. But they will be clear to the reader who would have gone
through the entire topic and will return to this chapter to get help in
classifying the soils.
Diagnostic subsurface horizons
Table 4.10
Diagnostic subsurface horizons (approximately equivalent to B
horizons).
Horizon
Abbreviation Simplified definition
Agric
agr
(Latin
ager =
field), illuvial below a cultivated
horizon, coatings of silts, clay and humus
Albic
alb
(L
. albus =
white), eluvial, aerated, often
overlying an illuvial horizon
Table 4.10 Contd...
