Soil Horizons Flashcards
O
Layer of organic material that has undergone physical and chemical breakdown. Usually top-most layer. Common in forests and absent in grasslands. Dark in color.
A
Layer beneath the O horizon that is dominated by mineral particles but have darkened due to the accumulation of organic material.
E
Layer beneath A and above B horizon that is lighter in color than both layers above and below it. These are areas of intense weathering, or elluviation, that are devoid of organic matter, clay, and iron/aluminum Usually occur in forests and rarely in grasslands.
B
Layer beneath A and sometimes E that consists largely of silicate clays and iron/aluminum oxides that have washed in, or illuviated, from the above layers.
C
Unconsolidated material underlying the solum, below the zone of greatest biological activity. In dry regions, gypsum and carbonates may be concentrated.
R
Consolidated rock with little evidence of weathering.
a
Highly decomposed organic matter
b
Buried soil horizon
c
concretions or nodules
co
Coprogenous Earth
d
Dense, unconsolidated material
di
diatomaceous earth
e
intermediately decomposed organic matter
f
frozen soil
ff
Dry Permafrost
g
strong gleying (mottling)
h
illuvial accumulation of organic matter
i
slightly decomposed organic matter
j
Jarosite (yellow sulfate mineral)
jj
cryoturbation (frost churning)
k
accumulation of carbonates
kk
engulfment of carbonates (>50% of soil by mass)
m
cementation or induration
n
accumulation of sodium
o
accumulation of iron and aluminum oxides
p
plowing or other human disturbance
q
accumulation of silica