LOCATION SINNIGAM MT+ND
Established Series
Rev. WDB-JAL-EMM
04/2014
SINNIGAM SERIES
The Sinnigam series consists of shallow, well drained soils that formed in material weathered from non-calcareous argillaceous sandstone, siltstone and shale. These soils are on bedrock-floored plains and hills. Slopes are 0 to 50 percent. Mean annual precipitation is about 17 inches, and mean annual temperature is about 42 degrees F.
TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive, frigid Lithic Argiustolls
TYPICAL PEDON: Sinnigam very stony clay loam, in grassland (colors are for dry soil unless otherwise noted).
A1--0 to 2 inches; dark grayish brown (10YR 4/2) very stony loam, very dark brown (10YR 2/2) moist; dark gray (10YR 4/1) coating on peds; strong very fine granular structure; slightly hard, very friable, moderately sticky and slightly plastic; many fine and very fine roots and few medium roots; many fine and very fine pores and common medium pores; 25 percent channers and cobbles, 5 percent stones; neutral (pH 7.3); clear wavy boundary. (1 to 4 inches thick)
A2--2 to 6 inches; dark grayish brown (10YR 4/2) very stony loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; hard, very friable, moderately sticky and slightly plastic; many fine and very fine roots and common medium roots; many fine and very fine pores and common medium pores; 35 percent channers and cobbles, 15 percent stones; neutral (pH 7.2); clear wavy boundary. (combined thickness of A horizons is 4 to 10 inches thick)
Bt1--6 to 11 inches; brown (7.5YR 5/2) very stony clay loam, dark brown (7.5YR 3/2) moist; strong fine and very fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many fine and very fine roots and few medium roots; many fine and very fine pores and common medium pores; continuous faint coating of unstained sand grains on faces of peds; many distinct brown (7.5YR 4/2) clay films on faces of peds; 35 percent channers and cobbles, 15 percent stones; neutral (pH 6.8); clear wavy boundary. (3 to 7 inches thick)
Bt2--11 to 17 inches; brown (7.5YR 5/4) extremely stony clay, brown (7.5YR 4/4) moist; strong fine and very fine subangular blocky structure; very hard, friable, moderately sticky and moderately plastic; many fine and very fine roots and few medium roots; many fine and very fine pores and few medium pores; many distinct brown (7.5YR 4/2) clay films on faces of peds; 50 percent channers and cobbles, 25 percent stones; slightly acid (pH 6.4); abrupt wavy boundary. (2 to 7 inches thick)
R--17 inches; fractured hard sandstone; some weathering in upper few inches and with a root mat formed at contact; clay films on some fragments in upper 3 inches.
TYPE LOCATION: Cascade County, Montana; 340 feet west and 1,920 feet north of the SE corner of sec. 31, T. 18 N., R. 6 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 and 12 inches or between 4 inches and the lithic contact.
Mollic epipedon thickness - 7 to 12 inches and includes all or part of the argillic horizon.
Depth to bedrock - 10 to 20 inches.
A1, A2 horizon
Hue: 7.5 YR or 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3; dry or moist
Texture: loam, silt loam, or clay loam
Clay content: 20 to 35 percent
Rock fragments: 5 to 50 percent--0 to 30 percent stones and cobbles, 5 to 45 percent gravel or channers
Reaction: pH 6.1 to 7.8
Bt1 horizon
Hue: 10YR, 7.5YR, 5YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3; dry or moist
Texture: clay loam, clay, silty clay loam, or silty clay
Clay content: 35 to 50 percent
Rock fragments: 35 to 70 percent--5 to 35 percent stones and cobbles, 20 to 70 percent gravel or channers
Reaction: pH 6.1 to 7.8
Bt2 horizon
Hue: 10YR, 7.5YR, 5YR
Value: 4, 5 or 6 dry, 4 or 5 moist
Chroma: 2, 3, or 4; dry or moist
Texture: clay loam, clay, or silty clay loam, or silty clay
Clay content: 35 to 50 percent
Rock fragments: 35 to 70 percent--5 to 50 percent stones and cobbles, 15 to 70 percent gravel or channers
Reaction: pH 6.1 to 7.8
COMPETING SERIES:
Ratonwest (NV) - has periods of maximum precipitation from July through October.
GEOGRAPHIC SETTING:
Landform - bedrock-floored plains and hills.
Elevation - 3,000 to 6,000 feet.
Slope - 0 to 50 percent.
Parent material - clayey materials derived from the non-calcareous argillaceous sandstone, siltstone, and shale.
Climate - long, cold winters; moist springs and summers.
Mean annual precipitation - 15 to 19 inches, most of which falls during spring and early summer.
Mean annual temperature - 39 to 45 degrees F.
Frost-free period - 85 to 135 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: Sinnigam soils are used mainly as rangeland and for dryland crops. Potential native vegetation is mainly bluebunch wheatgrass, Idaho fescue, rough fescue, and western wheatgrass.
DISTRIBUTION AND EXTENT: Sinnigam soils are widely distributed in the areas bordering the mountain front in central Montana. They are of moderate extent. MLRAs 54, 58A, 43B, and 46
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Carbon County area, Montana, 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from the soil surface to a depth of 11 inches (A1, A2, Bt1 horizons)
Argillic horizon - from a depth of 6 inches to 17 inches
Particle-size control section - from the top of the argillic to the lithic contact (Bt1, Bt2 horizons) or from the soil surface to a depth of 14 inches if the lithic is at 14 inches (A1, A2, Bt1, Bt2 horizons).
Soil interpretation records: MT0126, MT0191.
Sinnigam soils have an ustic moisture regime and a frigid temperature regime.
National Cooperative Soil Survey
U.S.A.