Lab 2
Soil Properties and Profiles
Activities for Today
 Texture: Determine texutral classes by feel, and identify
textures of unknown samples;
 Soil Color: Understand terminology of the Munsell color
system (hue, value, chroma) and use it to determine soil
color;
 Learn the nomenclature for master horizon suffixes, and
transition horizons, and use them in labeling horizons on a
monolith or soil profile description.
Soil Texture
 Textural classes of soils
are named on their
predominant feel and
correspond to
percentages of sand,
silt, and clay.
Soil Texture
 Sandy textures- feel gritty
 Silty textures- feel smooth, soft, and floury
 Clay textures- stiff, waxy, and plastic
How to Texture
 Golf-ball-sized amount of soil in your hand
 Soil needs to be moist but not wet(add water
slowly)
 Knead the soil in your hand, between your thumb
and fingers.
 Ribbon (?)/ Gritty, waxy, smooth
How To Texture
<1” (weak)
ribbon; not
stiff, waxy
1-2”
(moderate)
ribbon
> 2” ribbon; v.
stiff, waxy
Very gritty
SAND/
LOAMY
SAND
SANDY
LOAM
SANDY CLAY
LOAM
CLAY
Intermediate
gritty vs.
smooth
-------
LOAM
CLAY LOAM
CLAY
--------
SILT LOAM
SILTY CLAY
LOAM
CLAY
Makes NO
ribbon
Very smooth;
little grit
Soil Color
 Dark brown to black- ( A
horizon) top soils,
humus- decomposed
organic material. A few
percent of humus gives a
brownish color and up to
5% the soil becomes
black.
Soil Color
 Reds and Yellows- (B
horizons) iron oxide
formed during
weathering,
 Fe+3 is well oxidized
(well-drained)
Soil Color
 Grey colors are caused
by reduced Iron (Fe+2 )
 Water has excluded
oxygen from diffusion
into soil
 Other pigments are
leached out from
horizons (humus, iron
oxides)
Soil Color Determination
Hue- is the dominant spectral color of the entire
page of chips. 10YR- all chips on the page are
composed of 10 parts of yellow(Y) to 1 part red(R).
Value – lightness or darkness of the color. 8- light
color and 2 – dark color (high humus content)
Chroma- brightness or dullness of a color chip. 1dull (grayish/waterlogged) and 8 bright (oxidation)
Munsel Color Chart
10YR 5/3
Hue
Value
Chroma
Soil Color
 Matrix color- main or
background color
 Mottles – other colors
within the matrix
 Redoximorphic features-
reduction of Fe and
oxidation of Fe.
Grey Mottles
Soil Structure
Horizon Designations
 O Horizon: organic debris
a – Highly decomposed litter
e – intermediate , partially decomposed litter
i - slightly decomposed, identifiable litter
A Horizon: contains humus
p – plowed, shown by sharp boundary with horizon
below ( abrupt transition)
b – buried, A-type horizon found buried in profile
E horizon: light-colored, leached; NO suffixes
Horizon Designations
 B Horizon: material moved INTO
h- illuvial humus present
t- clay inc. compared to A; clay films
w- NO clay increase; blocky structure
*g- gleyed(chroma ≤ 2)
C Horizon: weathered parent material
r- hard to dig; almost R
*g – gleyed (chroma ≤ 2)
“types” of B
horizons: only
1 in each
profile
Horizon Designations
 Suffixes that are number are used to indicate
different parts of the same horizon. Bt-Bt1, Bt2
 Transition horizon- occurs between two master
horizons that have the properties of both.
“AE” transition layer is between A and E
horizons, more like an A than an E.
O: leaf litter at top
either “a”, “e”, or “i”
A: topsoil (humus)
add “p” if abrupt
E: same texture as A; often light color
Transition horizons: either EB or BE
B horizon
either “t”, “w”, or “h”; add “”g”
Transition (maybe)
C horizon: add “g” or “r” if necessary
R: cant dig it….
Soil Profile
_ 0-1”
_ _1”-6”
10YR 3/4
_ _6”-13”
10YR 6/3
_ 13”-25” 2.5YR 4/6
_ 25”-35” 5YR 5/6
_ _35”-47”
_ _47+”
hardwood leaves and twigs
sandy loam
granular
sandy loam
granular
clay
blocky
clay loam
blocky
saprolite
massive
hard gneiss and schist
Soil Profile
Oi_ 0-1”
_A_1”-6”
10YR 3/4
_E_6”-13” 10YR 6/3
_Bt 13”-25” 2.5YR 4/6
_BC 25”-35” 5YR 5/6
_C_35”-47”
_R_47+”
hardwood leaves and twigs
sandy loam
granular
sandy loam
granular
clay
blocky
clay loam
blocky
saprolite
massive
hard gneiss and schist
___--0 to 8 inches; reddish brown (5YR 4/4) loam; moderate medium granular
structure; friable; many fine roots; common fine pores; common fine black
concretions; slightly acid, abrupt smooth boundary. (2 to 11 inches thick)
___--8 to 17 inches; yellowish red (5YR 4/6) clay; moderate medium subangular blocky
structure; firm, sticky, plastic; common fine roots; few fine pores; many fine black
concretions; common distinct clay films on faces of peds; slightly acid; gradual wavy
boundary.
___--17 to 25 inches; yellowish red (5YR 4/8) clay; common fine distinct brownish
yellow (10YR 6/6) mottles; moderate medium subangular blocky structure; firm,
sticky, plastic; few fine roots; few fine pores; common black concretions; common
distinct clay films on faces of peds; slightly acid; gradual wavy boundary. (Combined
thickness of the Bt horizon is 12 to 35 inches.)
___--25 to 36 inches; yellowish red (5YR 4/8) clay loam; common medium faint reddish
yellow (7.5YR 6/6) and common fine distinct yellowish brown (10YR 5/4) mottles;
weak subangular blocky structure; firm, sticky, plastic; few fine black concretions;
common fine lenses of gray clayey saprolite; slightly acid; gradual wavy boundary. (3
to 15 inches thick)
___--36 to 60 inches; mottled yellowish red (5YR 4/8), reddish yellow (7.5YR 6/6) and
yellowish brown (10YR 5/4) highly weathered saprolite that has a sandy clay loam
texture; massive; friable; many black and gray minerals; slightly acid
___--0 to 8 inches; reddish brown (5YR 4/4) loam; moderate medium granular
structure; friable; many fine roots; common fine pores; common fine black
concretions; slightly acid, abrupt smooth boundary. (2 to 11 inches thick)
___--8 to 17 inches; yellowish red (5YR 4/6) clay; moderate medium subangular blocky
structure; firm, sticky, plastic; common fine roots; few fine pores; many fine black
concretions; common distinct clay films on faces of peds; slightly acid; gradual wavy
boundary.
___--17 to 25 inches; yellowish red (5YR 4/8) clay; common fine distinct brownish
yellow (10YR 6/6) mottles; moderate medium subangular blocky structure; firm,
sticky, plastic; few fine roots; few fine pores; common black concretions; common
distinct clay films on faces of peds; slightly acid; gradual wavy boundary. (Combined
thickness of the Bt horizon is 12 to 35 inches.)
___--25 to 36 inches; yellowish red (5YR 4/8) clay loam; common medium faint reddish
yellow (7.5YR 6/6) and common fine distinct yellowish brown (10YR 5/4) mottles;
weak subangular blocky structure; firm, sticky, plastic; few fine black concretions;
common fine lenses of gray clayey saprolite; slightly acid; gradual wavy boundary. (3
to 15 inches thick)
___--36 to 60 inches; mottled yellowish red (5YR 4/8), reddish yellow (7.5YR 6/6) and
yellowish brown (10YR 5/4) highly weathered saprolite that has a sandy clay loam
texture; massive; friable; many black and gray minerals; slightly acid
Ap--0 to 8 inches; reddish brown (5YR 4/4) loam; moderate medium granular structure;
friable; many fine roots; common fine pores; common fine black concretions; slightly
acid, abrupt smooth boundary. (2 to 11 inches thick)
Bt1--8 to 17 inches; yellowish red (5YR 4/6) clay; moderate medium subangular blocky
structure; firm, sticky, plastic; common fine roots; few fine pores; many fine black
concretions; common distinct clay films on faces of peds; slightly acid; gradual wavy
boundary.
Bt2--17 to 25 inches; yellowish red (5YR 4/8) clay; common fine distinct brownish yellow
(10YR 6/6) mottles; moderate medium subangular blocky structure; firm, sticky,
plastic; few fine roots; few fine pores; common black concretions; common distinct
clay films on faces of peds; slightly acid; gradual wavy boundary. (Combined thickness
of the Bt horizon is 12 to 35 inches.)
BC--25 to 36 inches; yellowish red (5YR 4/8) clay loam; common medium faint reddish
yellow (7.5YR 6/6) and common fine distinct yellowish brown (10YR 5/4) mottles;
weak subangular blocky structure; firm, sticky, plastic; few fine black concretions;
common fine lenses of gray clayey saprolite; slightly acid; gradual wavy boundary. (3
to 15 inches thick)
C--36 to 60 inches; mottled yellowish red (5YR 4/8), reddish yellow (7.5YR 6/6) and
yellowish brown (10YR 5/4) highly weathered saprolite that has a sandy clay loam
texture; massive; friable; many black and gray minerals; slightly acid