LOCATION AMESHA                  MT

Established Series
Rev. DES-KTS-RJS
03/2011

AMESHA SERIES

The Amesha series consists of very deep, well drained soils that formed in calcareous alluvium or colluvium derived from mixed sources. These soils are on stream terraces, alluvial fans, fan remnants, hills or escarpments. Slopes are 0 to 60 percent. Mean annual precipitation is about 12 inches, and mean annual air temperature is about 42 degrees F.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Aridic Calciustepts

TYPICAL PEDON: Amesha loam, cultivated (colors are for dry soil unless otherwise noted).

Ap--0 to 4 inches; light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; 5 percent gravel; disseminated calcium carbonate; strongly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (4 to 8 inches thick)

Bk1--4 to 10 inches; very pale brown (10YR 7/3) loam, brown (10YR 5/3) moist; weak medium prismatic structure; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; many fine tubular pores; 5 percent gravel; common fine masses of calcium carbonate; continuous distinct calcium carbonate casts on undersides of gravel; violently effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 10 inches thick)

Bk2--10 to 28 inches; very pale brown (10YR 8/3) loam, very pale brown (10YR 7/3) moist; weak coarse blocky structure; hard, friable, slightly sticky and slightly plastic; common fine and very fine roots; few fine tubular pores; 5 percent gravel; many large masses of calcium carbonate; continuous distinct calcium carbonate coatings on gravel; violently effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (0 to 18 inches thick)

Bk3--28 to 49 inches; very pale brown (10YR 8/3) loam, pale brown (10YR 6/3) moist; weak coarse blocky structure separating to weak fine platy; hard, friable, slightly sticky and slightly plastic; few very fine roots and pores; 5 percent gravel; few masses of calcium carbonate; continuous distinct calcium carbonate coatings on gravel; violently effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (12 to 27 inches thick)

BCk--49 to 74 inches; very pale brown (10YR 8/3) loam, pale brown (10YR 6/3) moist; massive; hard, friable, slightly sticky and slightly plastic; 15 percent gravel; common faint calcium carbonate coatings on gravel; disseminated calcium carbonate; violently effervescent; moderately alkaline (pH 8.2).

TYPE LOCATION: Broadwater County, Montana; 1,200 feet east and 1,100 feet north of the SW corner of sec. 25, T.4N., R.1E.

RANGE IN CHARACTERISTICS:
Average annual soil temperature - 40 to 47 degrees F.
Depth to secondary carbonate accumulation - 4 to 8 inches
Control section - 10 to 18 percent clay and 15 to 50 percent fine sand or coarser

Note: Some pedons may have a BC horizon with soil properties similar to the BCk horizon.

Ap horizon
Hue: 10YR, 2.5Y or 5Y; dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 or 3; dry or moist
Texture: loam, sandy loam or silt loam
Clay content: 10 to 25 percent
Rock fragments: 0 to 40 percent--0 to 25 percent gravel, 0 to 20 percent cobbles
Calcium carbonate equivalent: 1 to 10 percent
Reaction: pH 7.4 to 8.4

Bk1 horizon
Hue: 10YR, 2.5Y or 5Y; dry or moist
Value: 5 to 8 dry; 4 to 6 moist
Chroma: 2 or 4; dry or moist
Texture: loam, sandy loam or silt loam
Clay content: 10 to 18 percent
Rock fragments: 0 to 15 percent--0 to 15 percent gravel, 0 to 5 percent cobbles
Calcium carbonate equivalent: 15 to 30 percent
Reaction: pH 7.9 to 8.4

Bk2 horizon
Hue: 10YR, 2.5Y or 5Y; dry or moist
Value: 6 to 8 dry; 5 to 7 moist
Chroma: 2 or 3; dry or moist
Texture: loam, sandy loam or silt loam
Clay content: 0 to 18 percent
Rock fragments: 0 to 15 percent--0 to 15 percent gravel, 0 to 5 percent cobbles
Calcium carbonate equivalent: 15 to 35 percent
Reaction: pH 7.9 to 8.4

Bk3 horizon
Hue: 10YR, 2.5Y or 5Y; dry or moist
Value: 6 to 8 dry; 5 to 7 moist
Chroma: 2 or 3; dry or moist
Texture: loam or sandy loam
Clay content: 10 to 18 percent
Rock fragments: 0 to 15 percent--0 to 15 percent gravel, 0 to 5 percent cobbles
Calcium carbonate equivalent: 15 to 35 percent
Reaction: pH 7.9 to 8.4

BCk horizon
Hue: 7.5YR, 10YR, 2.5Y or 5Y; dry or moist
Value: 6 to 8 dry; 5 to 7 moist
Chroma: 2 to 4; dry or moist
Texture: loam, sandy loam or fine sandy loam
Clay content: 10 to 18 percent
Rock fragments: 0 to 35 percent--0 to 30 percent gravel, 0 to 5 percent cobbles
Calcium carbonate equivalent: 10 to 25 percent
Reaction: pH 7.9 to 8.4

COMPETING SERIES:
Kalsted (MT) - have greater than 50 percent fine or coarser sand in the particle-size control section
Lakebench (CO) - have hues of 7.5YR or redder.
Redbull (WY) - is deep to paralithic contact

GEOGRAPHIC SETTING:
Landform - stream terraces, alluvial fans, fan remnants, hills or escarpments
Elevation - 3,500 to 6,500 feet
Slope - 0 to 60 percent
Parent material - calcareous alluvium or colluvium derived from mixed sources
Climate - cool with long, cold winters; moist springs; and warm summers
Mean annual precipitation - 10 to 14 inches
Mean annual temperature - 38 to 45 degrees F.
Frost-free season - 70 to 120 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed.

DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.

USE AND VEGETATION: Used mainly for nonirrigated and irrigated crops, pasture, and hay. The potential native vegetation is bluebunch wheatgrass, needleandthread, western wheatgrass, rough fescue, forbs, and shrubs.

DISTRIBUTION AND EXTENT: Valleys in western Montana. These soils are of moderate extent. MLRA 43B, 44B, 46 and 48A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Broadwater County Area, Montana, 1971.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to 4 inches (Ap horizon)
Calcic horizon - from 4 to 49 inches (Bk1, Bk2, Bk3 and BCk horizons)
Particle-size control section - from 10 to 40 inches (Bk2 and part of Bk3 horizons)

Amesha soils have a frigid temperature regime and an ustic moisture regime that borders on aridic.

ADDITIONAL DATA:
Lincoln Laboratory Data S70MT-7-3.
Soil interpretations records: MT0528, MT0791, MT0656, MT1052, and MT0909.

Classification changed from Borollic Calciorthids to Haplocalcidic Ustochrepts in 1994. Changed to Aridic Calciustepts in 1998.

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National Cooperative Soil Survey
U.S.A.