LOCATION BIG TIMBER MTEstablished Series
TAXONOMIC CLASS: Clayey, mixed, superactive, frigid, shallow Entic Haplustolls
TYPICAL PEDON: Big Timber clay loam, native grass. (Colors are for dry soil unless otherwise noted.)
A--O to 3 inches, reddish brown (5YR 5/3) clay loam, dark reddish brown (5YR 3/3) moist; weak fine granular structure; slightly hard, friable, moderately sticky and moderately plastic; strongly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (2 to 6 inches thick)
Bw--3 to 6 inches, weak red (2.5YR 4/2) clay loam, dark reddish brown (2.5YR 3/3) moist; moderate very fine angular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; 5 percent clay shale fragments; strongly effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (1 to 4 inches thick)
C1--6 to 18 inches, weak red (2.5YR 5/2) clay, dark reddish brown (2.5YR 3/4) moist; slightly hard, friable, moderately sticky and moderately plastic; 10 percent clay shale fragments; strongly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (O to 20 inches thick)
Cr--18 to 60 inches, reddish very fine grained sandstone, siltstone and clay shale; common threads of lime segregation on lower side of shale fragments and a few threads of lime in old root channels; moderately alkaline (pH 8.0).
TYPE LOCATION: Judith Basin County, Montana 1100 feet west and 350 feet north of the SE corner of sec. 32, T.18N., R.18E.
RANGE IN CHARACTERISTICS:
Soil Temperature - 40 to 47 degrees F.
Mollic epipedon thickness - 7 to 10 inches
Depth to paralithic contact - 10 to 20 inches
A horizon - Hue: 7.5YR, 5YR or 2.5YR
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3
Clay content: 27 to 35 percent
Rock fragments: 0 to 30 percent pebbles
Calcium carbonate equivalent: 1 to 5 percent
Reaction: pH 7.4 to 8.4
Bw horizon - Hue: 7.5YR, 5YR or 2.5YR
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3
Texture: clay loam, clay or silty clay
Clay content: 35 to 50 percent
Rock fragments: 0 to 30 percent pebbles
Calcium carbonate equivalent: 5 to 10 percent
Reaction: pH 7.4 to 8.4
C1 horizon - Hue: 7.5YR, 5YR or 2.5YR
Value: 4, 5 or 6 dry; 3, 4 or 5 moist
Chroma: 2, 3 or 4
Texture: clay loam, clay or silty clay
Clay content: 35 to 50 percent
Rock fragments: 0 to 30 percent pebbles
Calcium carbonate equivalent: 5 to 10 percent
Reaction: pH 7.4 to 8.4
COMPETING SERIES:
There are no competing series.
GEOGRAPHIC SETTING:
Landform - hills
Eelevation - 3,200 to 5,000 feet.
Parent material - material weathered from shale and interbedded sandstone and shale.
Mean annual precipitation - 12 to 18 inches.
Mean annual temperature - 38 to 45 F.
Fost-free period - 105 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: Used mainly as native range. Vegetation is mainly bluebunch wheatgrass, needleandthread grass, and Sandberg bluegrass.
DISTRIBUTION AND EXTENT: Central Montana and adjacent portionS of Wyoming. Big Timber soils are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Judith Basin Area, Montana, 1963.
REMARKS: Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the surface to 7 inches (mixed) (A and Bw horizons); a paralithic contact at 18 inches (Cr horizon). Big Timber soils have an ustic moisture regime and a frigid temperature regime.