LOCATION ERNEM MTEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Lithic Argiustolls
TYPICAL PEDON: Ernem very stony loam, in rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 3 inches; grayish brown (10YR 5/2) very stony loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; slightly hard, very friable, sticky, plastic; many fine roots; many fine pores; 10 percent stones, 15 percent cobbles, 5 percent pebbles; mildly alkaline (pH 7.6); clear wavy boundary. (3 or 4 inches thick)
Bt1--3 to 7 inches; grayish brown (10YR 5/2) very stony heavy clay loam, dark brown (10YR 3/3) moist; moderate medium prismatic structure parting to strong very fine blocky; hard, friable, sticky, very plastic; thin continuous clay films on faces of peds; many fine roots; many fine pores; 25 percent stones, 10 percent cobbles, 10 percent pebbles; mildly alkaline (pH 7.6); clear wavy boundary. (4 to 6 inches thick)
Bt2--7 to 12 inches; brown (10YR 5/3) very stony heavy clay loam, dark brown (10YR 4/3) moist; strong medium prismatic structure parting to strong very fine blocky; hard, friable, sticky, very plastic; thin continuous clay films on faces of peds; many fine roots; many fine pores; 25 percent stones, 10 percent cobbles, 10 percent pebbles; mildly alkaline (pH 7.6); abrupt irregular boundary. (2 to 8 inches thick)
Bk--12 to 15 inches; light gray (10YR 7/2) very stony clay loam, brown (10YR 5/3) moist; moderate medium prismatic structure parting to very fine blocky; hard, friable, sticky, plastic; common fine roots; common fine pores; 25 percent stones, 10 percent cobbles, 10 percent pebbles; common fine and medium soft masses of lime; strongly effervescent; moderately alkaline (pH 8.2); abrupt wavy boundary. (2 to 4 inches thick)
R--15 inches; indurated sandstone.
TYPE LOCATION: Cascade County, Montana; 100 feet west and 10 feet south of the NE corner of sec. 36, T. 22 N., R. 1 E.
RANGE IN CHARACTERISTICS:
Soil temperature: 42 to 47 degrees F. Mollic epipedon thickness: 7 to 14 inches Moisture control section: approximately between the depths of 4 and 12 inches Control section: 35 to 50 percent clay and 35 to 60 percent rock fragments Depth to Bk horizon: 9 to 18 inches Depth to bedrock: 10 to 20 inches Phases: nonstony NOTE: Mollic epipedon includes all or part of the Bt1 horizon.
A horizon - Hue: 7.5YR, 10YR, 2.5Y Value: 4 or 5 dry, 2 or 3 moist Chroma: 2 or 3 Texture, less than 2 mm: loam or clay loam Clay content: 15 to 40 percent Rock fragments: 5 to 60 percent - stones and cobbles, 0 to 40 percent; pebbles, 5 to 25 percent 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, less than 2 mm: clay loam or clay Clay content: 35 to 50 percent Rock fragments: 35 to 60 percent - stones and cobbles, 5 to 45 percent; pebbles, 5 to 35 percent Reaction: pH 7.4 to 8.4
Bt2 horizon - Hue: 7.5YR, 10YR, 2.5Y Value: 5, 6, or 7 dry; 4 or 5 moist Chroma: 2 or 3 Texture, less than 2 mm: clay loam or clay Clay content: 35 to 50 percent Rock fragments: 35 to 60 percent - stones and cobbles, 5 to 45 percent; pebbles, 5 to 35 percent Reaction: pH 7.4 to 8.4 NOTE: This horizon may be lacking in some profiles.
Bk horizon - Hue: 7.5YR, 10YR, 2.5Y Value: 5, 6, or 7 dry; 4 or 5 moist Chroma: 2 or 3 Texture, less than 2 mm: clay loam or clay Clay content: 35 to 50 percent Rock fragments: 35 to 60 percent - stones and cobbles, 5 to 45 percent; pebbles, 5 to 35 percent Reaction: pH 7.4 to 8.4
COMPETING SERIES: These are the Raton and Sinnigam series. The Raton soils have formed in materials derived from basalt and have influence from ash, cinders, and other volcanic materials. They have a neutral reaction throughout the profile and have 15 to 20 inches of precipitation. The Sinnigam soils do not have a Bk horizon and are extremely stony in the Bt2 horizon.
GEOGRAPHIC SETTING: The Ernem soils are on uplands. Elevations are 3,000 to 4,000 feet. Slopes are 0 to 45 percent. These soils formed in material derived from consolidated sandstone. The climate is characterized by long, cold winters; moist springs; and warm, dry summers. Mean annual precipitation is 10 to 14 inches. Mean annual temperature is 40 to 45 degrees F. The frost-free period is 105 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately slow permeability.
USE AND VEGETATION: Ernem soils are used mainly as rangeland. Potential native vegetation is mainly western wheatgrass, needleandthread, Sandberg bluegrass, and fringed sagewort
DISTRIBUTION AND EXTENT: Ernem soils are of limited extent in north-central Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Cascade County, Montana, 1975.
REMARKS: Soil Interpretation Records: MT0037, MT0140. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from soil surface to 7 inches (A, Bt1 horizons); an argillic horizon from 3 to 12 inches (Bt1, Bt2 horizons); a lithic contact at 15 inches; a particle-size control section from 4 to 12 inches (Bt1, Bt2 horizons). Lithic Argiborolls feature a mollic epipedon more than 7 inches thick, an argillic horizon at least 3 inches thick, a lithic contact between 10 and 20 inches. Ernem soils have an ustic moisture regime bordering on aridic and have a frigid temperature regime.