LOCATION SHOOK MTEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Pachic Haplocryolls
TYPICAL PEDON: Shook coarse sandy loam, in rangeland. (Colors are for dry soil unless otherwise noted.)
A--O to 8 inches, very dark grayish brown (10YR 3/2) coarse sandy loam, black (10YR 2/1) moist; moderate medium granular structure; slightly hard, very friable, nonsticky and nonplastic; common fine and very fine roots; slightly acid (pH 6.4); clear smooth boundary. (6 to 12 inches thick)
Bw1--8 to 16 inches, brown (10YR 4/3) coarse sandy loam, dark brown (10YR 3/3) moist; moderate medium and coarse subangular blocky structure; hard, friable, slightly sticky and nonplastic; common fine and very fine roots; neutral (pH 6.6); gradual smooth boundary. (5 to 9 inches thick)
Bw2--16 to 28 inches, brown (10YR 4/3) coarse sandy loam, dark brown (10YR 3/3) moist; weak coarse subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; common fine and very fine roots; 10 percent pebbles; neutral (pH 6.8); gradual smooth boundary. (10 to 17 inches thick)
BC--28 to 36 inches, brown (10YR 5/3) very gravelly coarse sandy loam, brown (10YR 4/3) moist; weak fine subangular blocky; few fine and very fine roots; 50 percent pebbles; neutral (pH 6.8).
Cr--36 to 60 inches; decomposing granite bedrock (grus).
TYPE LOCATION: Ravalli County, Montana.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 36 to 41 degrees F.
Mollic epipedon thickness - 16 to 30 inches.
A horizon - Value: 3 or 4 dry, 2 or 3 moist
Chroma: 1, 2 or 3
Texture: loam, sandy loam or coarse sandy loam
Clay content: 5 to 27 percent
Rock fragments: 5 to 15 percent pebbles
Reaction: pH 5.6 to 7.3
Bw horizons - Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3
Texture: sandy loam or coarse sandy loam
Clay content: 5 to 15 percent
Rock fragments: 0 to 35 percent pebbles
Reaction: pH 6.1 to 7.3
BC horizon - Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 or 3
Clay content: 0 to 10 percent
Rock fragments: 15 to 50 percent pebbles
Reaction: pH 6.1 to 7.3
COMPETING SERIES:
Coutis (WY) - is very deep.
Earcree (ID) - is deep or very deep.
Gardners Fork (UT) - is very deep.
Grayhead (CO) - is deep.
Hailman (UT) - is deep.
Naz (ID) - is deep or very deep.
Razorba (CO) - is very deep.
Skyway (CO) - moderately deep to a lithic contact.
GEOGRAPHIC SETTING:
Landform - mountains
Elevation - 5000 to 7000 feet
Slope - 4 to 60 percent
Parent material - residuum or colluvium from granite
Mean annual precipitation - 15 to 25 inches
Mean annual temperature - 34 to 40 degrees F.
Frost-free period - 30 to 70 days
DRAINAGE AND PERMEABILITY: Well drained; moderately rapid permeability.
USE AND VEGETATION: These soils are used mainly for rangeland. The principal native vegetation is rough fescue, green needlegrass, indian ricegrass, Idaho fescue, needleandthread, and shrubs.
DISTRIBUTION AND EXTENT: Western Montana. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Bitterroot Valley Area, Montana, 1952.
REMARKS: Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the surface to 28 inches (A and Bw horizons); a paralithic contact at 36 inches (Cr horizon); a particle-size control section from 10 to 36 inches (part of the Bw1, the Bw2, and the BC horizons). Shooksoils have an ustic moisture regime and a cryic temperature regime.