LOCATION SOBOL OKEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, thermic Aquic Hapludalfs
TYPICAL PEDON: Sobol loam--in native range. (Colors are for moist soil unless otherwise stated.)
A--0 to 18 cm (0 to 7 inches); dark grayish brown (10YR 4/2) loam; moderate medium and fine granular structure; friable; many roots of all sizes; neutral; clear smooth boundary. [8 to 28 centimeters (3 to 11 inches) thick]
BA--18 to 36 cm (7 to 14 inches); dark grayish brown (2.5Y 4/2) clay loam; moderate medium granular structure; firm; many roots of all sizes; moderately acid; clear smooth boundary. [0 to 20 centimeters (0 to 8 inches) thick]
Bt1--36 to 64 cm (14 to 25 inches); coarsely mottled red (2.5YR 4/6), strong brown (7.5YR 5/6), and gray (10YR 5/1) clay; moderate fine and medium blocky structure; very firm; common fine roots; few fine fragments of shale; clay films on faces of peds; slightly acid; gradual smooth boundary. [10 to 36 centimeters (4 to 14 inches) thick]
Bt2--64 to 76 cm (25 to 30 inches); gray (10YR 5/1) clay; many medium distinct yellowish brown (10YR 5/6) redox concentrations; weak medium blocky structure; very firm; few fine roots; about 5 percent by volume of shale fragments less than 76 mm in diameter; patchy clay films on faces of peds; slightly alkaline; abrupt irregular boundary. [0 to 46 centimeters (0 to 18 inches) thick]
Cr--76 to 89 cm (30 to 35 inches); gray shale, tilted 20 degrees from horizontal.
TYPE LOCATION: Pushmataha County, Oklahoma; 853 meters (2,800 feet) east and 152 meters (500 feet) north of the southwest corner of sec. 23, T. 3 S., R. 16 E.
RANGE IN CHARACTERISTICS: Solum thickness and depth to shale bedrock ranges from 51 to 102 Centimeters (20 to 40 inches).
A horizon:
Hue: 10YR
Value: of 4 or 5
Chroma: of 1 to 3.
Redoximorphic features: where present, are in shades of gray or brown.
Texture: loam, silt loam, clay loam, stony loam, stony silt
loam or stony clay loam.
Coarse fragments: sandstone and shale, 0 to 30 percent by volume. 0 to 10 percent by volume is less than 76 mm in diameter and 0 to 20 percent by volume is more than 76 mm in diameter.
Reaction: slightly acid to strongly acid.
BA horizon:
Hue: 10YR or 2.5Y
Value: 4 or 5
Chroma: 2 to 6
Redoximorphic features: where present, are in shades of brown, red, or gray
Texture: clay loam or silty clay loam
Sandstone and shale fragments: less than 76 mm in diameter make up 0 to 10 percent by volume
Reaction: Slightly acid to very strongly acid.
Bt1 horizon:
Hue: 7.5YR to 5Y
Value: 4 to 6
Chroma: 1 to 6.
Coarse mottles in shades of red, yellow, brown, gray, and olive.
Texture: clay or silty clay.
Sandstone and shale fragments: less than 76 mm in diameter make up 0 to 10 percent by volume
Reaction: slightly acid to very strongly acid.
Bt2 horizon and where present, BC, horizon:
Hue: 7.5YR to 5Y
Value: 4 to 6
Chroma: 1 to 6
Redoximorphic features: in shades of red, yellow, brown, gray, and olive.
Texture: clay or silty clay and gravelly analogs.
Shale fragments: less than 76 mm in diameter make up 0 to 30 percent by volume
Reaction: moderately acid to moderately alkaline
Cr horizon:
Color: olive or gray
Parent material: shale, tilted 20 degrees to 90 degrees from the horizontal, fractured and cracks are more than 4 inches apart.
COMPETING SERIES: These are the
Grubbs and
Tupelo series.
Grubbs and Tupelo soils are of the same family, and have sola greater than102 centimeters (40 inches).
GEOGRAPHIC SETTING:
Landscape: very gently sloping to strongly sloping sideslopes and ridge crests in the valleys of the Ouachita Mountains.
Parent material: weathered from shale of Pennsylvanian age.
Mean annual temperature: ranges from 16 to 18 degrees C (61 degrees to 64 degrees F)
Mean annual precipitation ranges from 107 to 142 centimeters (42 to 56 inches)
Thornthwaite annual P-E indices: greater than 64.
Slopes: 2 to 20 percent.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Clebit,
Pickens,
Tuskahoma,
Yanush, and
Wister series.
Clebit, Pickens, and Tuskahoma soils: have sola less than 51 centimeters (20 inches) thick over bedrock.
Clebit and Pickens soils: have loamy-skeletal control sections
Tuskahoma soils: have an abrupt textural change
Yanush soils: have a loamy-skeletal control sections and sola more than 152 centimeters (60 inches) thick.
Wister soils: have sola more than 102 centimeters (40 inches) thick and have an abrupt textural change.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage: moderately well drained
Runoff: moderate to rapid
Saturated hydraulic conductivity: moderately low
Episaturation: 0.5 to 1.5 feet for short periods during winter and spring.
USE AND VEGETATION:
Use: tame pasture and native range for beef cattle.
Native vegetation: big bluestem, little bluestem, indiangrass, and switchgrass
Trees: winged elm, post oak, blackjack oak, and eastern red cedar
DISTRIBUTION AND EXTENT: Ouachita Mountains (MLRA 119), in valleys of southeastern Oklahoma and west central Arkansas.
The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Pushmataha County, Oklahoma; 1977.
REMARKS: These soils were previously included in the Eram series.
Modified format by LEK on 9/2006 to include metric conversions and change permeability to saturated hydraulic conductivity