LOCATION GRANTSDALE MTEstablished Series
TAXONOMIC CLASS: Coarse-silty over sandy or sandy-skeletal, mixed, superactive, frigid Calcic Haploxerolls
TYPICAL PEDON: Grantsdale loam, cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 9 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; slightly hard, very friable, nonsticky, and nonplastic; many very fine, fine, and medium roots; common fine and medium pores; neutral (pH 6.8); clear smooth boundary. (7 to 10 inches thick)
Bw--9 to 17 inches; pale brown (10YR 6/3) loam, brown (10YR 5/3) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, nonsticky, and nonplastic; common very fine, fine, and medium roots; common fine pores; neutral (pH 7.1); gradual smooth boundary. (7 to 10 inches thick)
Bk--17 to 32 inches; light gray (2.5Y 7/2) loam, grayish brown (2.5Y 5/2) moist; weak medium and coarse subangular blocky structure; slightly hard, very friable, nonsticky, and nonplastic; few fine roots; common fine pores; disseminated lime; strongly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (6 to 20 inches thick)
2BCk--32 to 36 inches; light gray (2.5Y 7/2) very gravelly loamy sand, grayish brown (2.5Y 5/2) moist; single grain; loose, nonsticky, and nonplastic; few fine roots; thin lime coats on underside of gravel; 50 percent gravel, 10 percent cobbles; strongly effervescent; moderately alkaline (pH 8.2); gradual smooth boundary. (0 to 6 inches thick)
2C--36 to 60 inches; light brownish gray (10YR 6/2) very gravelly loamy sand, dark grayish brown (10YR 4/2) moist; single grain; loose, nonsticky, and nonplastic; 50 percent gravel, 10 percent cobbles; slightly effervescent; slightly alkaline (pH 7.5).
TYPE LOCATION: Missoula County, Montana; 2,450 feet south of the NE corner of sec. 35, T. 12 N., R. 20 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 45 to 47 degrees F.
Moisture control section - approximately between the depths of 8 and 24 inches.
Mollic epipedon thickness - 7 to 16 inches
Depth to calcic horizon - 14 to 20 inches
Base saturation - 50 to 100 percent
Ap horizon - Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3 dry or moist
Texture: loam or silt loam
Clay content: 10 to 18 percent
Reaction: pH 6.1 to 7.3
Bw horizon - Hue: 10YR or 2.5Y dry or moist
Value: 4, 5, or 6 dry; 3 or 4 moist
Chroma: 2 or 3 dry or moist
Texture: loam, very fine sandy loam, or silt loam
Clay content: 10 to 18 percent
Reaction: pH 6.1 to 7.3
Bk horizon - Hue: 10YR or 2.5Y dry or moist
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2 or 3 dry or moist
Texture: loam, very fine sandy loam, or silt loam
Clay content: 10 to 18 percent
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.8 to 8.4
2BCk, 2C horizons - Hue: 10YR or 2.5Y dry or moist
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2 or 3 dry or moist
Texture: loamy sand or sand
Clay content: 5 to 10 percent
Rock fragments: 35 to 70 percent--5 to 20 percent cobbles; 30 to 50 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform- alluvial fans and stream terraces in intermountain valleys.
Elevation - 2,400 to 3,500 feet.
Slope - 0 to 4 percent.
Parent material - alluvium.
Climate - long, cold winters; moist springs; warm, dry summers.
Mean annual precipitation - 11 to 17 inches, much of which falls as snow and as spring rain.
Mean annual temperature - 43 to 45 degrees F.
Frost-free season - 90 to 125 days.
GEOGRAPHICALLY ASSOCIATED SOILS:
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability in the upper 32 inches and rapid in the lower part.
USE AND VEGETATION: Grantsdale soils are used for irrigated and dryland crops and for urban development.
DISTRIBUTION AND EXTENT: Grantsdale soils are of moderate extent in mountain valleys of western Montana. MLRA 44A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Bitterroot Valley Area, Montana, 1951.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from the soil surface to 9 inches (Ap horizon);
Cambic horizon - from 9 to 17 inches (Bw horizon);
Calcic horizon - from 17 to 36 inches (Bk and 2BCk horizon);
Particle-size control section - from 10 to 40 inches.
Grantsdale soils have a frigid temperature regime and a xeric moisture regime.
Soil Interpretation Record: MT0548.