LOCATION GREENOUGH MT+COEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Udic Haplustalfs
TYPICAL PEDON: Greenough silt loam, forested (colors are for dry soil unless otherwise noted).
Oi--0 to 2 inches; undecomposed and slightly decomposed forest litter.
E--2 to 10 inches; light brownish gray (10YR 6/2) silt loam, dark grayish brown (10YR 4/2) moist; weak, very fine granular structure; soft, very friable, nonsticky and slightly plastic; many fine, medium, and coarse roots; many very fine pores; 10 percent pebbles, moderately acid (pH 6.0); clear wavy boundary. (7 to 16 inches thick)
E/Bt--10 to 24 inches; E part (80 percent) is light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist which interfingers into the B part; B part (20 percent) is light brownish gray (2.5Y 6/2) silt loam, grayish brown (2.5Y 5/2) moist; texture mixed is silt loam; weak fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine, medium, and coarse roots; many very fine pores; 10 percent pebbles; slightly acid (pH 6.2); clear wavy boundary. (14 to 27 inches thick)
Bt1--24 to 51 inches; light brownish gray (2.5Y 6/2) silt loam, grayish brown (2.5Y 5/2) moist; weak medium and coarse subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine roots; common very fine pores; common faint clay films on faces of peds and in pores; 10 percent pebbles; neutral (pH 6.6); gradual wavy boundary. (7 to 15 inches thick)
Bt2--51 to 60 inches; light brownish gray (2.5Y 6/2) gravelly silt loam, grayish brown (2.5Y 5/2) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few fine roots; few faint clay films on faces of peds and in pores; 30 percent pebbles; neutral (pH 6.8).
TYPE LOCATION: Missoula County, Montana; 3,000 feet north and 1,300 feet west of the SE corner of sec. 35, T. 13 N., R. 15 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 46 degrees F.
Moisture control section - between 4 and 12 inches.
A BC horizon is allowed.
E horizon - Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 2 or 3
Clay content: 5 to 20 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles, 0 to 10 percent pebbles
Reaction: pH 5.6 to 6.5
E/Bt horizon - Hue: E part 10YR or 2.5Y; B part 10YR or 2.5Y
Value: E part 6, 7, or 8, B part 6 or 7 dry; E part 4, 5, or 6, B part 4 or 5 moist
Chroma: E part 2, 3, or 4; B part 2 or 3
Clay content: 5 to 20 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles, 0 to 10 percent pebbles
Reaction: pH 6.1 to 7.3
Bt horizons - Hue: 10YR or 2.5Y
Value: 6, 7, or 8 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: silty clay loam or silt loam
Clay content: 18 to 32 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles, 0 to 10 percent pebbles
Reaction: pH 6.1 to 7.3
Below 49 inches the rock fragments range from 0 to 35 percent.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - stream terraces; hills.
Elevation - 3,200 to 4,500 feet.
Slope - 4 to 35 percent.
Parent material - alluvium and colluvium from tertiary sediments.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 16 to 22 inches.
Mean annual temperature - 40 to 44 degrees F.
Frost-free period - 70 to 100 days.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: Greenough soils are used for timber production, woodland grazing, homesite development, and recreation. The native vegetation is ponderosa pine and Douglas-fir with an understory of pinegrass, common snowberry, and dwarf huckleberry.
DISTRIBUTION AND EXTENT: The Greenough soils are of moderate extent in western Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: St. Regis-Ninemile Area, Montana, 1970.
REMARKS: Soil interpretation record: MT0151. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the soil surface to 24 inches (E, E/Bt horizons); an albic horizon from 2 to 10 inches (E horizon); a glossic horizon from 10 to 24 inches (E/Bt horizon); an argillic horizon from 24 to 60 inches (Bt1, Bt2 horizons); a particle-size control section from 24 to 44 inches (Bt1 horizon). Greenough soils have a frigid temperature regime and an ustic moisture regime.