LOCATION CULP TXEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, thermic Vertic Argiustolls
TYPICAL PEDON: Culp clay loam--cropland.
(Colors are for dry soil unless otherwise stated.)
Ap--0 to 7 inches; dark grayish brown (10YR 4/2) clay loam,
very dark grayish brown (10YR 3/2) moist; moderate coarse blocky structure; hard, friable; few smooth pebbles of quartz up to about 1/2 inch in diameter; neutral; clear smooth boundary. (5 to 14 inches thick)
B21t--7 to 18 inches; dark grayish brown (10YR 4/2) sandy
clay loam, very dark brown (10YR 2/2) moist, with few fine faint brown mottles; moderate coarse blocky structure; hard, firm,
plastic; common clay films on faces of peds; few smooth pebbles of quartz up to about 1/2 inch in diameter; slightly acid; gradual smooth boundary. (5 to 12 inches thick)
B22t--18 to 44 inches; dark brown (10YR 4/3) sandy clay, dark brown (10YR 3/3) moist, with coarse distinct mottles of dark
grayish brown (2.5Y 4/2); strong coarse blocky structure; very
hard, extremely firm, plastic; prominent clay films on faces of
peds; few fine black concretions; few smooth pebbles of quartz up
to about 1/2 inch in diameter; mildly alkaline; gradual smooth boundary. (10 to 28 inches thick)
B23t--44 to 57 inches; mottled light olive brown (2.5Y 5/4),
dark grayish brown (2.5Y 4/2) clay loam; strong coarse blocky structure; very hard, extremely firm, plastic; common clay films
on ped faces; many fine calcium carbonate concretions and a few
black concretions; few smooth pebbles of quartz up to about 1/2
inch in diameter; moderately alkaline; calcareous; gradual wavy boundary. (10 to 20 inches thick)
B3ca--57 to 73 inches; mottled light yellowish brown (2.5Y
6/4), olive yellow (2.5Y 6/6), and brownish gray (10YR 4/2), clay loam; strong coarse blocky structure; very hard, very firm,
plastic; common calcium carbonate concretions and masses of soft lime; few black concretions; few smooth pebbles of quartz up to
about 1/2 inch in diameter; strongly alkaline; calcareous; clear smooth boundary. (10 to 18 inches thick)
C--73 to 99 inches; mottled yellow (10YR 8/8), and light gray (10YR 7/1) clay loam; strong fine platy structure; hard, firm, plastic; moderately alkaline and calcareous.
TYPE LOCATION: Hill County, Texas; about 6 miles southwest of Hillsboro and 2 miles southeast of Peoria. About 1 mile southeast from Peoria on gravel road, 0.5 mile east, then south on field
road to lower end adjacent to pasture. Site is 100 feet northeast
of pasture in cropland.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 50 to more than 80 inches. Pebbles throughout the pedon range from few to common and some pedons have a few pebbles on the surface that
range up to about 2 inches in size.
The A horizon ranges up to 14 inches thick and has dry colors of
dark grayish brown (10YR 4/2), very dark grayish brown (10YR 3/2), dark brown (10YR 4/3; 3/3). Texture is loam, sandy clay loam, or clay loam and the horizon is neutral or mildly alkaline.
Average clay content of the upper 20 inches of the Bt horizon
ranges from 35 to 50 percent. The lower Bt horizons are clay,
sandy clay loam, or clay loam and they are mildly or moderately alkaline. Few to common hard concretions and soft masses of
calcium carbonate are in the lower B2t horizons, mainly below a
depth of 40 inches.
The B21t horizon has base colors of very dark gray (10YR 3/1),
dark gray (10YR 4/1), dark grayish brown (10YR 4/2), very dark grayish brown (10YR 3/2), dark brown (10YR 3/3; 7.5YR 3/2), dark reddish brown (5YR 3/2), and dark reddish gray (5YR 4/2) with mottling of reddish yellow (5YR 6/6), dark reddish gray (5YR 4/2), reddish brown (5YR 4/3), dark brown (7.5YR 4/2), brown (7.5YR 5/4; 10YR 5/3), and light yellowish brown (10YR 6/4). This horizon is clay, sandy clay loam, or clay loam and ranges from neutral
through moderately alkaline. The matrix of the B22t horizon is
olive (5Y 4/3), dark grayish brown (2.5Y 4/2), very dark grayish brown (10YR 3/2), brown (10YR 5/3), and yellowish brown (10YR 5/4, 5/6) with many to common coarse mottles of red, yellow, gray, and brown. The B23t horizon has common to many medium to coarse
mottles of olive, brown, yellow, or gray.
The B3ca horizon is mottled olive, yellow, gray, or brown.
The C horizon is mottled brown, yellow, gray, and olive. It is mildly alkaline or moderately alkaline and calcareous.
COMPETING SERIES: These are the
Abilene,
Anocon,
Blanket,
Blum,
Bonham,
Brewer,
Chatt,
Crockett,
Durant,
Frankirk,
Lofton,
Tabler, and
Wilson series. Abilene, Blanket, Brewer, and Frankirk soils
lack vertic properties and have unmottled Bt horizons. Anocon and Blum soils lack vertic properties. Bonham soils have a udic
moisture regime. Chatt soils lack argillic horizons. Crockett, Durant, Tabler, and Wilson soils have montmorillonitic mineralogy. Lofton soils lack mottles in the Bt horizon.
GEOGRAPHIC SETTING: Culp soils are on nearly level to gently
sloping uplands. Slopes range from 0 to 3 percent and are plane
to convex. They formed in loamy and clayey sediments on old high terraces of the Blackland Prairie. The climate is moist subhumid. Mean annual rainfall ranges from 28 to 35 inches. Mean annual temperature ranges from 64 degrees to 69 degrees F. Thornthwaite
P-E indices range from 48 to 62.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing
Blum,
Chatt,
Crockett, and
Wilson series and the
Houston Black,
Lamar,
Lewisville, and
Venus series. Houston Black soils contain intersecting slickensides and have montmorillonitic mineralogy. Lamar, Lewisville, and Venus soils do not have thick dark surfaces
or argillic horizons.
DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is
slow and permeability is slow.
USE AND VEGETATION: Mostly cropped to cotton, grain sorghum,
corn, and small grain. Native vegetation is mainly mid and tall grasses such as big bluestem, little bluestem, indiangrass, and switchgrass
DISTRIBUTION AND EXTENT: Central Texas, mainly on old high
terraces within the Blackland Prairie. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Hill County, Texas; 1975.
REMARKS: These soils were formerly classified in the Reddish
Prairie great soil group and included in the Bonham series.