LOCATION SLOCUM             MT+CO WY
Established Series
Rev. DES-JAL
01/2001

SLOCUM SERIES


The Slocum series consists of very deep, somewhat poorly drained soils that formed in loamy alluvium. These soils are on low stream terraces and floodplains. Slopes are 0 to 15 percent. Mean annual precipitation is about 23 inches, and mean annual temperature is about 42 degrees F.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive Aquic Haplocryolls

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

A--0 to 14 inches; dark gray (10YR 4/1) fine loam, black (10YR 2/1) moist; moderate medium crumb structure; soft, friable, moderately sticky and moderately plastic; many very fine roots and interstitial pores; neutral (pH 6.9); clear wavy boundary. (10 to 15 inches thick)

Bw--14 to 24 inches; light brownish gray (10YR 6/2) clay loam, very dark grayish brown (10YR 3/2) moist; common fine brown stains around root channels; weak medium and coarse blocky structure; hard, firm, moderately sticky and moderately plastic; many very fine roots; many very fine pores; slightly alkaline (pH 7.6); clear wavy boundary. (5 to 15 inches thick)

Bg--24 to 33 inches; light brownish gray (10YR 6/2) silty clay loam, very dark gray (10YR 3/1) moist; many fine distinct brown redox concentrations; weak medium and coarse blocky structure; hard, friable, slightly sticky and slightly plastic; common fine roots; many fine and very fine pores; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 10 inches thick)

Cg--33 to 60 inches; gray (10YR 5/1) clay loam, very dark gray (10YR 3/1) moist; massive; hard, friable, moderately sticky and moderately plastic; water table at 33 inches; moderately alkaline (pH 8.2); clear wavy boundary.

2Cg--60 to 65 inches; gray (10YR 5/1) very fine sandy loam, very dark gray (10YR 3/1) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; moderately alkaline (pH 8.2).

TYPE LOCATION: Judith Basin County, Montana; 1,400 feet west and 600 feet south of the E 1/4 corner of sec. 22, T. 19 N., R. 9 E.

RANGE IN CHARACTERISTICS:

Soil temperature - 35 to 42 degrees F.
Mollic epipedon thickness - 10 to 15 inches.
Depth to seasonal high water table - 24 to 42 inches.

A horizon - Hue: 10YR or 2.5Y
Value: 3, 4, or 5 dry; 2 or 3 moist
Chroma: 1 or 2
Texture: loam, silty clay loam, or clay loam
Clay content: 15 to 35 percent
Reaction: pH 6.6 to 7.3

Bw horizon - Hue: 10YR or 2.5Y
Value: 4, 5, or 6 dry; 3 or 4 moist
Chroma: 1 or 2
Texture: clay loam or loam
Clay content: 20 to 35 percent
Reaction: pH 7.4 to 7.8

Bg horizon - Hue: 10YR or 2.5Y
Value: 4, 5, or 6 dry; 3 or 4 moist
Chroma: 1 or 2
Texture: silty clay loam or clay loam
Clay content: 27 to 35 percent
Reaction: pH 7.9 to 8.4

Cg horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 1 or 2
Texture: clay loam or loam
Clay content: 20 to 35 percent
Reaction: pH 7.9 to 8.4

2Cg horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 1 or 2
Clay content: 10 to 20 percent
Reaction: pH 7.9 to 8.4

COMPETING SERIES:

Gallatin (MT) - has horizons of secondary carbonate accumulation.
Outlet (ID) - has horizons of secondary carbonate accumulation.

GEOGRAPHIC SETTING:

Landform - low stream terraces and floodplains.
Elevation - 4,500 to 7,000 feet.
Parent material - noncalcareous alluvium from mixed sources.
Climate - long, cold winters; cool, moist springs; short summers.
Mean annual precipitation - is 15 to 30 inches.
Mean annual temperature - 38 to 46 degrees F.
Mean annual summer temperature - 54 to 59 degrees F.
Frost-free period - 50 to 70 days.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained; moderate permeability.

USE AND VEGETATION: Slocum soils are used mainly for hay and pasture. Potential native vegetation is mainly northern reedgrass, tufted hairgrass, basin wildrye, and some conifer and deciduous trees.

DISTRIBUTION AND EXTENT: Slocum soils are widely distributed and inextensive.

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

SERIES ESTABLISHED: Ravalli County (Bitteroot Valley area), Montana, 1952.

REMARKS: Soil Interpretations Record: MT0245. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the surface to 14 inches (A horizon); a cambic horizon from 14 to 33 inches (Bw, Bg horizons); a lithologic discontinuity at 60 inches (2Cg horizon); a particle-size control section from 10 to 40 inches (A, Bw, Bg, Cg horizons). Slocum soils have a cryic temperature regime and an ustic moisture regime bordering on udic.


National Cooperative Soil Survey
U.S.A.