LOCATION DOBY MTEstablished Series
TAXONOMIC CLASS: Clayey, smectitic, shallow Ustic Haplocryolls
TYPICAL PEDON: Doby clay loam - native grass. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; dark grayish brown (10YR 4/2) clay loam, very dark brown (10YR 2/2) moist; moderate very fine granular structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine roots; 20 percent soft shale fragments; neutral (pH 6.8); abrupt smooth boundary.
A2--2 to 5 inches; gray (10YR 5/1) clay, very dark gray (10YR 3/1) moist; moderate very fine granular structure; hard, friable, moderately sticky and moderately plastic; many very fine roots; 20 percent soft shale fragments; neutral (pH 6.8); clear smooth boundary. (Combined thickness of A horizon is 4 to 7 inches)
Bw--5 to 13 inches; gray (10YR 5/1) clay, very dark gray (10YR 3/1) moist; moderate medium prismatic structure parting to moderate medium and fine subangular blocky; very hard, firm, moderately sticky and very plastic; many very fine roots; 20 percent soft shale fragments; slightly alkaline (pH 7.4); clear irregular boundary. (5 to 10 inches thick)
C--13 to 19 inches; gray (10YR 5/1) shaly clay, very dark gray (10YR 3/1) moist; thick platy structure; extremely hard, extremely firm, moderately sticky and moderately plastic; many very fine roots in fractures and cleavage planes; 60 percent shale; slightly alkaline (pH 7.6); clear wavy boundary. (5 to 10 inches thick)
Cr--19 to 60 inches; gray (10YR 5/1) semiconsolidated shale, very dark gray (10YR 3/1) moist.
TYPE LOCATION: Glacier County, Montana; 2,300 feet east and 330 feet south of NW corner of sec. 17, T.30N., R.11W.
RANGE IN CHARACTERISTICS:
Soil temperature - 36 to 45 degrees F.
Moisture control section - between 4 and 12 inches.
Depth to Cr horizon - 10 to 20 inches.
A horizons - Hue: 10YR or 2.5Y
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1 or 2
Clay content: 30 to 40 percent
Rock fragments: 0 to 15 percent pebbles or channers
Reaction: pH 6.6 to 7.8
Bw horizon - Hue: 10YR or 2.5Y
Value: 4, 5 or 6 dry, 3 or 4 moist
Chroma: 1, 2, 3 or 4
Texture: clay or silty clay
Clay content: 40 to 55 percent
Rock fragments: 0 to 25 percent pebbles or channers
Reaction: pH 6.6 to 8.4
C horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 1 or 2
Texture: clay or silty clay
Clay content: 40 to 55 percent
Rock fragments: 0 to 35 percent pebbles or channers
Reaction: pH 6.6 to 8.4
COMPETING SERIES:
Yankeeboy (CO) - has a udic moisture regime.
GEOGRAPHIC SETTING:
Landform - sedimentary plains and hills.
Elevation - 4,600 to 7,500 feet
Slope - 2 to 60 percent
Parent material - material derived from semiconsolidated shale.
Climate - long, cold winters; cool, moist springs; warm summers.
Mean annual precipitation - 15 to 24 inches.
Mean annual temperature - 34 to 43 degrees F.
Frost-free period - 50 to 70 days.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Used mainly for range. Vegetation is rough and Idaho fescue, prairie rose, and shrubby cinquefoil.
DISTRIBUTION AND EXTENT: This series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Glacier County (Blackfeet Reservation-Cut Bank Area), Montana, 1969.
Remarks: Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the surface to 13 inches (A1, A2 and Bw horizons); a particle-size control section from 10 to 19 inches (Bw and C horizons); a paralithic contact at 19 inches (Cr horizon). Doby soils have a cryic temperature regime and an ustic moisture regime.