LOCATION RALORE MTEstablished Series
TAXONOMIC CLASS: Clayey, smectitic, frigid, shallow Aridic Leptic Natrustalfs
TYPICAL PEDON: Ralore clay loam, in rangeland (colors are for dry soil unless otherwise noted).
A--0 to 2 inches; yellowish brown (10YR 5/4) loam, dark yellowish brown (10YR 4/4) moist; weak medium angular blocky structure parting to weak fine angular blocky; soft, very friable, slightly sticky and slightly plastic; many very fine roots; slightly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (2 to 4 inches thick)
Btn--2 to 7 inches; light yellowish brown (10YR 6/4) silty clay loam, yellowish brown (10YR 5/4) moist; strong fine prismatic structure parting to strong medium angular blocky; very hard, firm, sticky and plastic; many very fine roots; many very fine pores; many faint clay films on faces of peds and lining pores; slightly effervescent; very strongly alkaline (pH 9.1); clear smooth boundary. (4 to 9 inches thick)
Btkn--7 to 12 inches; pale brown (10YR 6/3) silty clay loam, brown (10YR 5/3) moist; moderate medium angular blocky structure; very hard, firm, sticky and plastic; many very fine roots; many very fine pores; common faint clay films on faces of peds; disseminated lime, common fine masses of lime; strongly effervescent; very strongly alkaline (pH 9.1); clear smooth boundary. (4 to 10 inches thick)
Byz--12 to 16 inches; light brownish gray (10YR 6/2) silty clay loam, grayish brown (10YR5/2) moist; hard, friable, sticky and plastic; common very fine roots; roots matted at the contact with the Cr horizon; few very fine pores; 10 percent soft shale fragments; few fine masses of gypsum and other salts; disseminated lime; slightly effervescent; strongly alkaline (pH 9.0); clear smooth boundary. (0 to 6 inches)
Cr--16 to 60 inches; light gray (10YR 6/1) semiconsolidated shale that crushes to silty clay loam, gray (10YR 5/1) moist; slightly alkaline (pH 7.4).
TYPE LOCATION: Rosebud County, Montana; 600 feet east and 2,300 feet south of the NW corner of sec. 29, T. 10 N, R. 42 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 40 to 47 degrees.
Moisture control section - between 4 and 12 inches, dry in all parts between four-tenth and five-tenths of the cumulative days per year when the soil temperature at a depth of 20 inches is 41 degrees F or higher.
Depth to Btkn horizon - 6 to 10 inches.
Depth to bedrock - 10 to 20 inches, mainly 12 to 18 inches.
A horizon - Hue: 10YR or 2.5Y
Value: 4, 5, or 6 dry; 4 or 5 moist
Chroma: 3 or 4
Texture: loam, silt loam, or silty clay loam
Clay content: 18 to 35 percent
Electrical conductivity: 0 to 2 mmhos/cm
Reaction: pH 7.8 to 9.0
Btn horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4
Texture: clay, clay loam, or silty clay loam
Clay content: 35 to 45
Electrical conductivity: 2 to 4 mmhos/cm
Sodium adsorption ratio: 13 to 20
Reaction: pH 7.9 to 9.6
Btkn horizon - Hue: 10YR or 2.5Y
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: clay, clay loam, or silty clay loam
Clay content: 35 to 45 percent
Calcium carbonate equivalent: 5 to 15 percent
Electrical conductivity: 2 to 4 mmhos/cm
Sodium adsorption ratio: 20 to 30
Reaction: pH 7.9 to 9.6
Byz horizon - Hue: 10YR, 2.5Y, or 5Y
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Calcium carbonate equivalent: 1 to 15 percent
Electrical conductivity: 4 to 8 mmhos/cm
Sodium adsorption ratio: 20 to 40
Reaction: pH 7.9 to 9.6
Cr horizon - semiconsolidated shale or semiconsolidated interbedded shale and siltstone
COMPETING SERIES:
There are no competing series.
GEOGRAPHIC SETTING:
Landform - sedimentary plains; hills.
Elevation - 1,900 to 3,500 feet.
Slope- 0 to 30 percent.
Parent material - semiconsolidated shale or semiconsolidated interbedded shale and siltstone.
Climate - long cold winters; moist springs; warm summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual temperature - 38 to 45 degrees.
Frost-free period - 100 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Ralore soils are used mainly for rangeland. Potential native vegetation is mainly western wheatgrass, prairie junegrass, blue gramma, forbs, and shrubs.
DISTRIBUTION AND EXTENT: Ralore series is of moderate extent in eastern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Custer County, Montana 1995; proposed Rosebud County, Montana 1994.
REMARKS: Soil interpretation record: MT1553. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the surface to 2 inches (A horizon); a natric horizon from 2 to 12 inches (Btn, Btkn horizons); a horizon of secondary calcium carbonate accumulation from 7 to 12 inches (Btkn horizon); a horizon of gypsum accumulation from 12 to 16 inches (Byz horizon); a particle-size control section from 2 to 12 inches (Btn, Btkn horizons).