LOCATION HINTERLAND MTEstablished Series
TAXONOMIC CLASS: Clayey, smectitic, frigid Aridic Lithic Argiustolls
TYPICAL PEDON: Hinterland clay loam, in rangeland (colors are for dry soil unless otherwise noted).
A--0 to 3 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots; many fine and very fine pores; neutral (pH 6.8); clear smooth boundary. (2 to 7 inches thick)
Bt1--3 to 6 inches; brown (10YR 4/3) clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure parting to moderate fine subangular blocky; hard, firm, sticky and plastic; many very fine roots; many fine and very fine pores; many distinct clay films on faces of peds; neutral (pH 6.6); clear smooth boundary. (1 to 4 inches thick)
Bt2--6 to 12 inches; brown (10YR 4/3) channery clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure parting to moderate fine subangular blocky; hard, firm, sticky and plastic; many very fine roots; many very fine pores; many distinct clay films of faces of peds; 20 percent sandstone channers; neutral (pH 6.6); clear smooth boundary. (3 to 10 inches thick)
R--12 inches; hard fractured sandstone with thin clay skins on surface of rock fragments in the upper 6 inches.
TYPE LOCATION: Musselshell County, Montana; 200 feet north and 2,600 feet west of the SE corner of sec. 32, T. 11 N., R. 25 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 and 12 inches, dry in all parts between four-tenths and five-tenths of the cumulative days per year when the soil temperature at a depth of 20 inches is 41 degrees F or above. Is not dry in the moisture control section during June and the first half of July.
Mollic epipedon thickness - 7 to 12 inches.
Particle-size control section - 35 to 45 percent clay.
Depth to bedrock - 10 to 20 inches.
A thin transition BC horizon that has up to 80 percent coarse fragments and that may have some lime crusts on the undersides is allowed.
A horizon - Hue: 7.5YR, 10YR, 2.5Y
Value: 2 or 3 moist
Chroma: 2 or 3
Texture: loam or clay loam
Clay content: 20 to 35 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles; 0 to 10 percent channers or pebbles
Reaction: pH 6.6 to 7.8
Bt1 horizon - Hue: 7.5YR, 10YR, 2.5Y
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3
Texture: clay loam or silty clay loam
Clay content: 27 to 40 percent
Rock fragments: 0 to 15 percent--0 to 5 percent stones and cobbles; 0 to 10 percent pebbles or channers
Reaction: pH 6.6 to 7.8
Bt2 horizon - Hue: 7.5YR, 10YR, 2.5Y
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 2, 3, or 4
Texture: clay loam or clay
Clay content: 35 to 50 percent
Rock fragments: 15 to 35 percent--0 to 5 percent stones and cobbles; 15 to 30 percent pebbles or channers
Reaction: pH 6.6 to 7.8
COMPETING SERIES: There are no competing series in the same family.
GEOGRAPHIC SETTING:
Landform - bedrock-floored sedimentary plains and hills.
Elevation - 2,200 to 5,200 feet.
Slopes- 0 to 35 percent.
Parent material - residuum or colluvium derived from hard sandstone.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual air temperature - 39 to 45 degrees F.
Frost-free period - 95 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: Hinterland soils are used mainly for rangeland. Potential native vegetation is mainly bluebunch wheatgrass, green needlegrass, and western wheatgrass.
DISTRIBUTION AND EXTENT: Hinterland soils are moderately extensive in central Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Musselshell County, Montana, 1996.
REMARKS: Soil interpretation record: MT1462.
Diagnostic horizons and features recognized in this pedon are: mollic epipedon - after mixing the top 7 inches (A, part of Bt horizon); argillic horizon - from 3 to 12 inches (Bt1 and Bt2 horizons); particle-size control section - from the surface to 12 inches (A, Bt1, Bt2 horizons); lithic contact - at a depth of 12 inches (R horizon). Hinterland soils have a frigid temperature regime and an ustic moisture regime that borders on aridic.