LOCATION GALLATIN MT+WYEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive Aquic Haplocryolls
TYPICAL PEDON: Gallatin loam, native hay (colors are for dry soil unless otherwise noted).
A1--0 to 4 inches; very dark gray (10YR 3/1) loam, black (10YR 2/1) moist; moderate medium subangular blocky structure parting to moderate medium granular; slightly hard, friable, nonsticky and slightly plastic; many very fine and common roots; few vesicular pores; neutral (pH 6.6); clear smooth boundary.
A2--4 to 14 inches; very dark grayish brown (10YR 3/2) loam, black (10YR 2/1) moist; moderate medium subangular blocky structure parting to moderate medium granular; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common fine vesicular pores; neutral (pH 6.6); gradual wavy boundary. (Combined thickness of the A1 and A2 horizons is 14 to 30 inches.)
AB--14 to 23 inches; dark grayish brown (10YR 4/2) sandy clay loam, very dark grayish brown (10YR 3/2) moist; moderate coarse and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; common fine vesicular pores; slightly alkaline (pH 7.4); gradual wavy boundary. (0 to 10 inches thick)
Bw--23 to 28 inches; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; few fine faint yellowish brown (10YR 5/6) redox concentrations, dark yellowish brown (10YR 4/4) moist; moderate coarse and fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; few very fine roots; few fine vesicular pores; slightly alkaline (pH 7.8); gradual wavy boundary. (5 to 15 inches thick)
Bk--28 to 36 inches; grayish brown (2.5Y 5/2) clay loam, dark grayish brown (2.5Y 4/2) moist; many medium distinct light olive brown (2.5Y 5/4) redox concentrations, olive brown (2.5Y 4/4) moist; massive; very hard, firm, moderately sticky and moderately plastic; common medium soft masses of lime; strongly effervescent, slightly alkaline (pH 7.8); gradual wavy boundary. (5 to 15 inches thick)
Bkg--36 to 60 inches; light gray (5Y 6/1) gravelly clay loam, gray (5Y 5/1) moist; many medium prominent olive yellow (2.5Y 6/6) redox concentrations, light olive brown (2.5Y 5/6) moist; massive; extremely hard, firm, moderately sticky and moderately plastic; common medium soft masses of lime; strongly effervescent, moderately alkaline (pH 8.4).
TYPE LOCATION: Teton County, Montana; about 2,400 feet west and 500 feet south of the NE corner of sec. 4, T. 24 N., R. 8 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 40 to 47 degrees F.
Mollic epipedon thickness - 16 to 30 inches.
Depth to seasonal high water table - 24 to 42 inches.
A1 and A2 horizons - Hue: 10YR or 2.5Y
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 1 or 2
Clay content: 18 to 27 percent
Rock fragments: 0 to 15 percent pebbles
EC: 0 to 2 mmhos/cm
SAR: 0 to 13
Reaction: pH 7.0 to 7.6
AB horizon - Hue: 10YR or 2.5Y
Value: 4, 5, or 6 dry; 3, or 4 moist
Chroma: 1 or 2
Texture: sandy clay loam, loam, or clay loam
Clay content: 27 to 35 percent
Rock fragments: 0 to 15 percent pebbles
EC: 0 to 2 mmhos/cm
SAR: 0 to 13
Reaction: pH 7.0 to 7.6
Bw horizon - Hue: 10YR or 2.5Y
Value: 4, 5, or 6 dry; 3, or 4, moist
Chroma: 2 or 3
Texture: sandy clay loam, loam, or clay loam
Clay content: 27 to 35 percent
Rock fragments: 0 to 15 percent pebbles
EC: 0 to 2 mmhos/cm
SAR: 0 to 13
Reaction: pH 7.2 to 7.8
Bkg1 horizon - Hue: 2.5Y or 10YR
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: sandy clay loam or clay loam
Clay content: 27 to 35 percent
Rock fragments: 0 to 15 percent pebbles
EC: 0 to 2 mmhos/cm
SAR: 0 to 13
Reaction: pH 7.4 to 8.4
Bkg horizon - Hue: 2.5Y, 5Y or 10YR
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 1 or 2
Texture: loam, clay loam or sandy clay loam
Clay content: 18 to 35 percent
Rock fragments: 0 to 20 percent pebbles
Reaction: pH 7.4 to 8.4
COMPETING SERIES:
Outlet (ID) - has a calcic horizon; mollic epipedon is less than 16 inches thick.
Slocum (MT) - does not have horizon of secondary carbonate accumulation.
GEOGRAPHIC SETTING:
Landform - valley bottoms and stream terraces.
Elevation - 5,000 to 6,500 feet.
Slope - 0 to 15 percent.
Parent material - alluvium derived mainly from sedimentary rocks.
Climate - long, cold winters; moist springs; warm summers. Mean annual precipitation - 15 to 19 inches.
Mean annual temperature - 38 to 45 degrees F.
Frost-free period - 30 to 70 days.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow permeability.
USE AND VEGETATION: Gallatin soils are used mainly as rangeland and pasture. Potential native vegetation is mainly tall reedgrass, manna grass, tufted hairgrass, sedges, cottonwood, and willows.
DISTRIBUTION AND EXTENT: Gallatin soils are of moderate extent in western Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Gallatin County, Montana, 1905.
REMARKS: Soil Interpretation Records: MT0637 and MT0724. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the soil surface to 23 inches (A1, A2 and AB horizons); a cambic horizon from 23 to 28 inches (Bw horizon); carbonate accumulations from 28 to 60 inches (Bk and Bkg horizons); a gleyed horizon from 36 to 60 inches (Bkg horizon); a particle-size control section from 10 to 40 inches (A2, AB, Bw, and Bk horizons).
Gallatin soils have a cryic temperature regime and an ustic moisture regime.