LOCATION CHISCA ALEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, thermic Vertic Hapludalfs
TYPICAL PEDON: Chisca loam--on a convex 10 percent slope under
mixed hardwoods and pine at an elevation of about 560 feet.
(Colors are for moist soil.)
A1--0 to 2 inches; dark grayish brown (10YR 4/2) loam; weak
medium granular structure; friable; many fine roots; about 2
percent by volume of fine and medium angular sandstone gravel; few wormcasts; very strongly acid; clear smooth boundary.
A2--2 to 5 inches; yellowish brown (10YR 5/4) loam; weak
medium granular structure; friable; common fine roots; about 2 percent by volume of fine and medium angular sandstone gravel; few wormcast; strongly acid; abrupt smooth boundary. (Combined
thickness of the A horizon is 2 to 9 inches thick.)
Bt1--5 to 13 inches; yellowish red (5YR 4/6) clay; strong
medium angular and subangular blocky structure; firm, slightly plastic; few fine and medium roots; thin continuous distinct clay films on faces of some peds; about 2 percent by volume of medium angular, sandstone gravel; few old cracks filled with brown loam; very strongly acid; clear smooth boundary.
Bt2--13 to 23 inches; red (2.5YR 4/6) clay; many medium
distinct strong brown (7.5YR 5/6) mottles; strong medium angular
and subangular blocky structure; very firm, plastic; few fine and medium roots; thin continuous distinct clay films on faces of most peds; about 1 percent by volume of fine and medium angular
sandstone gravel; common pressure faces; very strongly acid;
gradual smooth boundary. (Combined thickness of the Bt horizon is
15 to 34 inches thick.)
BC--23 to 32 inches; red (2.5YR 4/6) clay; many large
prominent light brownish gray (10YR 6/2) and few medium distinct strong brown (7.5YR 5/6) mottles; weak coarse angular and
subangular blocky structure; very firm, plastic; few fine and
medium roots; thin continuous faint clay films on faces of some
peds; common pressure faces; few nonintersecting slickensides;
very strongly acid; gradual smooth boundary. (0 to 16 inches
thick.)
C1--32 to 44 inches; mottled red (2.5YR 5/6); light brownish
gray (10YR 6/2), and strong brown (7.5YR 5/6) clay; massive; very firm; many intersecting and nonintersecting slickensides forming wedge-shaped aggregates; strongly acid; clear smooth boundary.
C2--44 to 55 inches; light olive brown (2.5Y 5/4) clay;
common medium distinct light gray (10YR 7/1) mottles; few shale fragments; massive; very firm; many intersecting slickensides
forming wedge-shaped aggregates; medium acid. (Combined thickness
of the C horizon is 0 to 25 inches thick.)
Cr--55 to 65 inches; mottled brown and gray, weathered,
fractured shale; shale rock structure; hard; moderately alkaline; calcareous.
TYPE LOCATION: Colbert County, Alabama; about 3 miles south of Tuscumbia, 1 mile south on Frankford Road from its intersection
with U. S. Highway 72 and 0.4 mile east on Henderson Point Road;
site is 75 feet south of road, 1,800 feet east and 2,640 feet
south of NW corner of sec. 20, T. 4 S., R. 11 W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 20 to 50 inches and depth to soft alkaline shale bedrock ranges from 40 to
60 inches. In some pedons thin layers of channery limestone
overlie the shale bedrock. Reaction of the A, Bt, and BC or CB horizons is extremely acid to strongly acid except where the
surface layer has been limed. The C horizon is very strongly acid
to moderately alkaline. The Cr horizon is neutral to moderately alkaline.
The A horizon has hue of 10YR or 2.5Y, value of 3 to 5, and chroma
of 2 to 6. Texture is silt loam, loam, fine sandy loam, sandy
loam, silty clay loam, clay loam, gravelly silt loam, gravelly
loam, gravelly fine sandy loam, or gravelly sandy loam.
Some pedons have an E or BE horizon less than 5 inches thick with
hue of 7.5YR to 2.5Y, value of 4 to 6, and chroma of 4 to 6.
Texture is the same as the A horizon.
The upper part of the Bt horizon has hue of 2.5YR to 7.5YR, value
of 4 or 5, and chroma of 4 to 8. The lower part of the Bt horizon has hue of 2.5YR to 7.5YR, value of 4 or 5, and chroma of 4 to 8
with common to many mottles in shades of red, gray, or brown; or
it is mottled in varying shades of yellow, brown, red, and gray. Texture of the Bt horizon is clay. Some pedons have a thin layer
of silty clay or silty clay loam in the upper part of the Bt
horizon.
The BC or CB horizon, where present, has hue of 2.5YR to 2.5Y,
value of 4 to 6, and chroma of 4 to 8 with common to many mottles
in varying shades or red, gray, or brown; or it is mottled in
varying shades of yellow, brown, red, or gray. Texture is clay.
The C horizon, where present, has hue of 10YR to 5Y, value of 5 to
7, and chroma of 1 to 6 with common to many mottles in varying
shades or red, gray, or brown; or it is mottled in varying shades
of yellow, brown, red, or gray. Texture is clay or silty clay. Percent by volume of cobbles, channers, or flagstones of limestone range from 0 to 10 percent, percent by volume of gravel or
channery of shale range from 0 to 50 percent.
The Cr horizon is weathered alkaline shale. Some pedons contain channers or flagstones of limestone.
COMPETING SERIES: These are the
Oktibbeha and
Vaiden series in the same family and the
Conasauga and
Firestone series in closely
related families. Oktibbeha and Vaiden soils are underlain by
marly clay or marl. Conasauga and Firestone soils are underlain
by alkaline shale at depths of less than 40 inches.
GEOGRAPHIC SETTING: Chisca soils are on gently sloping to strongly sloping uplands and ridges of limestone valleys and sloping to
steep hillsides of the Appalachian Plateau. Slopes range from 2
to 45 percent. The soils formed in residuum weathered from
alkaline shale and limestone.
GEOGRAPHICALLY ASSOCIATED SOILS: These are
Barfield,
Capshaw,
Chenneby,
Colbert,
Leesburg,
Talbott, and
Tupelo series. Barfield and Talbott soils are on similar landforms but have limestone
bedrock at depths of less than 40 inches. Capshaw, Colbert, and Tupelo soils are on slightly lower to lower landforms, are
underlain by limestone bedrock, and have a control section with
less than 60 percent clay. Chenneby soils are on flood plains and
do not have an argillic horizon. Leesburg soils are on adjacent colluvial slopes and have a control section with less than 35
percent clay.
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability; medium to rapid runoff.
USE AND VEGETATION: Most of the Chisca soils are used for woodland. Forests are mixed hardwoods and pines. Some areas are used for pasture and hay. Small areas are used for cultivated crops.
DISTRIBUTION AND EXTENT: Limestone valleys adjacent to the Appalachian Plateau in Alabama and possibly Georgia and Tennessee. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES PROPOSED: Colbert County, Alabama, 1981. The series is
named for a small community in Colbert County.
REMARKS: Chisca soils were formerly included in the Colbert and Talbott series. Chisca soils on steep slopes were formerly
included in miscellaneous land types.
ADDITIONAL DATA: Data are available on 5 pedons in Colbert County.